December 2009 CLASSIFICATION DEFINITIONS 203 … of preparing alcoholic beverages includ-ing distillation. 532, ... FRACTIONAL DISTILLATION A separatory distillation operation in which

December 2009 CLASSIFICATION DEFINITIONS 203 - 1

December 2009

CLASS 203, DISTILLATION: PROCESSES, SEP-ARATORY

SECTION I - CLASS DEFINITION

GENERAL STATEMENT OF CLASS SUBJECTMATTER

This is the residual class for processes for separating aliquid mixture (distilland) by vaporizing and condensingat least a portion thereof to isolate in the condensed liq-uid (distillate) or in the unvaporized portion (residue) acomparatively pure compound which was present assuch in the original mixture. The original mixture maybe a solid under normal atmospheric conditions if it liq-uifies below the vaporization temperature.

To come within the purview of this class (203) the distil-land must have a boiling point above 0°C. under normalatmospheric pressure. Because the C4 hydrocarbonshave boiling points above and below 0°C., all C4 hydro-carbons are arbitrarily classified as having boilingpoints above 0°C.

Sublimination (see Glossary) is excluded from this class(203). See References to Other Classes, below.

When claims are presented which recite a specificchemical compound or mixture to be recovered, the enu-merated classifications set forth in Lines With OtherClasses must be consulted to see if such subject matteris provided for in other than Class 203.

SECTION II - LINES WITH OTHER CLASSESAND WITHIN THIS CLASS

LINES WITH CHEMICAL COMPOSITIONCLASSES

(1) Products whether claimed in terms of their composi-tion or claimed in terms of the process of making areclassified in the appropriate composition class even ifthe process merely recites a separatory distillation oper-ation.

(2) Processes including a chemical reaction and a sepa-ratory distillation operation are classified here onlywhen the chemical reaction merely facilitates the isola-tion by the separatory distillation operation of a preex-isting substance in the distilland. See Class 260,Chemistry of Carbon Compounds, Class 423, Chemistryof Inorganic Compounds, or Class 585, Chemistry ofHydrocarbon Compounds for a process of preparing a

compound and isolating it by a separatory distillationprocess.

(3) Processes including a separatory distillation step anda disparate physical separation step, such as extraction,are classified in this class (203) if the disparate separat-ing step follows the distillation step and the process isnot otherwise provided for. When the disparate separa-tion step precedes the distillation step, the process isgenerally provided for elsewhere.

See Class 260, Chemistry of Carbon Compounds(including Class 585, Chemistry of Hydrocarbon Com-pounds) or Class 423, Chemistry of Inorganic Com-ponds, for a process of extraction of a compound, eitheras a sole step or followed by isolating the compound bya separatory distillation process.

(4) Processes directed solely to a separatory distillationoperation are classified in this class (203) unless other-wise provided for:

(a) Processes for the distillation of metals, such as mer-cury or zinc are classified in Class 75, Specialized Met-allurgical Processes, Compositions for Use Therein,Consolidated Metal Powder Compositions, and LooseMetal Particulate Mixtures.

(b) Processes for distilling a mineral oil in which theproduct isolated is a pure compound are classified inthis class (203). However, when the distillation processproduces as the product a mineral oil, it is classified inClass 208, Mineral Oils: Processes and Products.

(c) Processes which include fermentation are classifiedin 435, Chemistry: Molecular Biology and Microbiol-ogy, even if such processes also include distillation.

(d) Processes for distilling fermented beverage to pro-duce a distilled beverage are classified in Class 426,Food or Edible Material: Processes, Compositions, andProducts, but processes for distilling a fermented bever-age to isolate alcohol are classified here (203).

(e) When a patent contains a Class 423, Chemistry ofInorganic Compounds, process claim and a Class 203,Distillation: Processes, Separatory, process claim, thepatent is classified in Class 423 and cross-referenced toClass 203.

PROCESSES INCLUDING EVAPORATION

Processes for evaporating without a condensing step aregenerally excluded from this class. For specific lines

203 - 2 CLASSIFICATION DEFINITIONS December 2009

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between the processes of this class and other processesincluding an evaporating step, see below.

This class (203) is distinguished from Class 34, Dryingand Gas or Vapor Contact With Solids, in that the mate-rial treated herein (203) is a liquid or a liquefiable solidfrom which volatile material is to be separated and con-densed or absorbed. The product recovered must be arelatively pure substance which existed as such in theoriginal material. The material of Class 34 is a solid orsemi-solid from which it is desired to remove a liquid,leaving the residue chemically unchanged.

Class 134, Cleaning and Liquid Contact With Solids,takes claimed combinations of work handling or sup-porting means or steps with means or steps to apply aliquid to the work, as by spraying or immersion, wheresaid liquid is distilled or evaporated, whether or not theresulting vapor is (1) directly contacted with the work or(2) condensed for reuse to contact the work. When onlythe liquid distillation subcombination or the vapor-phasework contact subcombination has been claimed, seeabove for the line between Class 203 and Class 34.

Class 62, Refrigeration, includes processes for separat-ing a mixture of substances having boiling points below0°C. (32°F) at atmospheric pressure by the steps ofvaporizing a component and condensing the vapor.When a patent includes species claims classifiable inClass 62 and Class 203, it is classified in Class 62 andcross-referenced to Class 203.

Class 95, Gas Separation: Processes, takes processes inwhich gas is removed from a liquid wherein the gas isnormally gaseous at a temperature of 0°C and a pressureof 760 mm Hg (e.g., hydrogen sulfide (H2S), carbonmonoxide (CO), carbon dioxide (CO2), etc.). The vola-tile need not be condensed. The line between Class 95and Class 203 is that a Class 203 operation requiresvaporizing and condensing a material which is normallya liquid, while Class 95 does not.

Class 159, Concentrating Evaporators, takes processesfor concentrating solids in solution or suspension byvolatilizing the liquid. It is distinguished from this class(203) by the fact that the volatile material is not con-densed.

Some additional classes which provide for processesthat include an evaporating step or a concentrating stepare: Class 23, Chemistry: Physical Processes; Class 127,Sugar, Starch, and Carbohydrates; Class 260, Chemistry,Carbon Compounds; Class 426, Food or Edible Mate-

rial: Processes, Compositions, and Products; Class 520,Synthetic Resins or Natural Rubbers; Class 585, Chem-istry of Hydrocarbon Compounds; Class 588, Hazard-ous or Toxic Waste Destruction or Containment.

CLASS 201, DISTILLATION: PROCESSES, THER-MOLYTIC, IS SUPERIOR TO CLASS 203.

SECTION III - REFERENCES TO OTHERCLASSES

SEE OR SEARCH CLASS:23, Chemistry: Physical Processes, subclass 294

For general sublimation processes see andClass.

62, Refrigeration, appropriate subclasses for pro-cesses and apparatus peculiar to removing heatfrom a substance.

75, Specialized Metallurgical Processes, Composi-tions for Use Therein, Consolidated MetalPowder Compositions, and Loose Metal Partic-ulate Mixtures, appropriate subclasses for aprocess of reducing an ore to the metallic stateor refining molten metal involving distillationor for a sublimination process.

75, Specialized Metallurgical Processes, Composi-tions for Use Therein, Consolidated MetalPowder Compositions, and Loose Metal Partic-ulate Mixtures, for the sublimation of metals.

95, Gas Separation: Processes, for processesinvolving steps resulting in separation of a gasfrom a fluid mixture comprising (a) a gas andsolid or liquid particles entrained therein, (b) aliquid and gas entrained therein, or (c) a plural-ity of gases.

99, Foods and Beverages: Apparatus, subclasses275+ for apparatus for preparing beverages.

106, Compositions: Coating and Plastic, appropri-ate subclasses for a coating composition whichmay be applied to surfaces of the distillationapparatus or utilized for making apparatus of aparticular composition.

122, Liquid Heaters and Vaporizers, appropriatesubclass for heating liquids, superheating orcooling the vapors generated and conservingthe heat in the liquid or vapor in a closed sys-tem.

134, Cleaning and Liquid Contact With Solids, sub-classes 1+ for a cleaning process, particularlysubclass 12 for a process including the step ofdistilling the treating agent and subclass 31 fora process including the step of condensing agas or vapor.


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159, Concentrating Evaporators, for apparatus andprocesses not more specifically provided forelsewhere, peculiar to the concentration of sol-ids held in solution or suspension by evapora-tion of the liquid containing them. See sub-classes 48.1+ for a process of concentrating byspraying and subclass 49 for a process of con-centrating by a filming operation. See also sub-classes 5+ for a film type evaporator.

210, Liquid Purification or Separation, appropriatesubclasses for a process for purifying or sepa-rating a liquid by (1) sorption or ionicexchange, (2) filtration, (3) liquid-liquidextraction, (4) purification by destruction orconversion of a constituent thereof.

261, Gas and Liquid Contact Apparatus, appropri-ate subclasses for apparatus adapted to producean intimate contact between gases and liquidsand see (2) Note under the class definition.

366, Agitating, subclasses 219+ for apparatus foragitating a liquid or a particulate material bymotion of the container, and subclasses 241+for a fixed container with movable stirringapparatus, particularly subclasses 262+ forpump type stirrers.

426, Food or Edible Material: Processes, Composi-tions, and Products, subclasses 11+ for pro-cesses of preparing alcoholic beverages includ-ing distillation.

532, Organic Compounds, appropriate subclassesfor general sublimation processes.

585, Chemistry of Hydrocarbon Compounds, sub-class 801 for general sublimation processes.

588, Hazardous or Toxic Waste Destruction or Con-tainment, subclasses 300 through 320 for dis-tillation process in the chemical destruction ofhazardous or toxic waste.

SECTION IV - GLOSSARY

AZEOTROPIC DISTILLATION

A separatory distillation of a liquid in which a substanceis added to the distilland mixture in order to assist sepa-ration of its components by forming with one or more ofthe components a mixture having a minimum boilingpoint. (The art has also used the term for a distillationprocess in which two substances in the starting materialare removed by their forming a minimum boiling mix-ture).

CONDENSATE

See “distillate” in the class definition.

CONVECTIVE DISTILLATION

A separatory distillation operation in which an inertvapor is passed through a heated liquid to reduce thepartial vapor pressure of the component in the liquiddesired to be recovered. It permits the separation of heatsensitive high boiling substances at temperatures belowtheir decomposition temperature. Steam distillation isthe most commonly used type of convective distillation.

DISTILLAND

For purposes of this class the liquid or liquefied materialwhich is undergoing a distillation operation.

DISTILLATE

The liquid product condensed from vapor during thedistillation operation.

EVAPORATION

The process of changing a solid or liquid into a vapor.This is the generic term for both sublumination andvaporization. It differs from “distillation” in that distilla-tion includes the additional step of condensing vaporproduced to a liquid.

EXTRACTIVE DISTILLATION

A separatory distillation in which a generally less vola-tile substance, often referred to as a solvent, is added tothe distillation column to preferentially remove somecomponent of the vapor by dissolving it. The added sub-stance and the dissolved component are removed belowthe point at which the less volatile substance is added tothe distillation column.

FLASH VAPORIZATION

The process in which the distilland is heated under pres-sure high enough to prevent ebullition (usually aboveatmospheric pressure) and the heated distilland is thenintroduced into a zone of lesser pressure resulting in thevolatilization of at least a position of the distilland.

FRACTIONAL DISTILLATION

A separatory distillation operation in which distillate iscollected over specific temperature intervals.


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MOLECULAR DISTILLATION

A high vacuum separatory distillation process for distill-ing high boiling, heat sensitive substances in which thedistance from the liquid surface to the condensing sur-face is less than the mean free path.

SEPARATORY DISTILLATION

A process of vaporizing at least a portion of a liquidmixture (distilland) and condensing at least a portion ofthe vapor to separate the liquid mixture into distinctparts. The substances recovered as products must havepreexisted in the original mixture.

STEAM DISTILLATION

A form of convective distillation in which the inertvapor passed through the heated liquid is steam. Theadding of water or steam to a distillation column or theadding of water to a distilland is not within the meaningof this term.

SUBLIMATION

A process in which a solid passes into the vapor statewithout liquefaction and the vapor returns to the solidstate without passing through the liquid phase.

THERMOLYTIC DISTILLATION

A distillation in which material found in the distillandundergoes chemical decomposition (thermolysis) toform different substances at least some of which are vol-atile at the temperature employed. The volatile sub-stances are recovered by condensation or sorption.

VAPORIZATION

The process of changing a liquid into a vapor. See“Evaporation”.

SUBCLASSES

1 WITH MEASURING, TESTING ORINSPECTING:This subclass is indented under the class defini-tion. Processes combined with the positivestep of visually, chemically or physically deter-mining some chemical or physical characteris-tic or property of the feed, vapor, residue orcondensate.

(1) Note. The chemical or physical charac-teristic must be positively stated in theclaim for the purpose of this andindented subclasses, e.g., measuring thetemperature. Heating to a specified tem-perature is not determining a characteris-tic within the purview of this andindented subclasses.

SEE OR SEARCH CLASS:73, Measuring and Testing, appropriate

subclasses for measuring and testingapparatus.

137, Fluid Handling, subclasses 2+ for aprocess in which a condition or char-acteristic of a fluent material is deter-mined and used to control the system.

162, Paper Making and Fiber Liberation, subclass 238 for a digester with auto-matic control means.

196, Mineral Oils: Apparatus, subclass 132for mineral oil vaporizing apparatusprovided with automatic control.

201, Distillation: Processes, Thermolytic, subclass 1 for a process directed tothermolytic distillation combined withmeasuring, testing or inspecting.

202, Distillation: Apparatus, subclasses151, 160, 193, 196, 206 for distillationapparatus having control devices andsee “SEARCH CLASS” under eachsubclass.

361, Electricity: Electrical Systems andDevices, appropriate subclasses forelectrical systems not otherwise clas-sified and see “SEARCH CLASS”under the class definitions for varioustypes of electrical systems.

436, Chemistry: Analytical and Immuno-logical Testing, subclasses 230+ for aprocess of chemically testing notcombined with a distillation process.

2 Of temperature or pressure:This subclass is indented under subclass 1.Processes directed to specifically determiningthe temperature and/or pressure of the feed,vapor, residue or condensate.

SEE OR SEARCH CLASS:73, Measuring and Testing, appropriate

subclasses for device for quantita-tively measuring temperature and


December 2009

700+ for a device for the direct mea-surement of pressure.

137, Fluid Handling, subclasses 2+ for aprocess of fluid handling in which oneor more characteristics or conditionsof a fluent material are determined,particularly subclass 14 for a processinvolving pressure control.

202, Distillation: Apparatus, subclass 160for a separatory distillation systemincluding a column provided withautomatic temperature and/or pressurecontrol, and see “SEARCH THISCLASS, SUBCLASS” and“SEARCH CLASS” thereunder forrelated fields of search.

374, Thermal Measuring and Testing, sub-classes 100+ for a device for quantita-tively determining temperature.

532, Organic Compounds, appropriate sub-classes for a process directed to tem-perature control.

585, Chemistry of Hydrocarbon Com-pounds, subclass 956 for a collectionof patents concerned with condition-responsive control procedures inhydrocarbon purification processes.

3 Of concentration:This subclass is indented under subclass 1.Processes including the steps of determiningthe concentration of the feed, vapor, residue orcondensate.

SEE OR SEARCH CLASS:73, Measuring and Testing, subclasses

32+ for apparatus for determiningdensity and/or specific gravity of aliquid.

137, Fluid Handling, subclasses 2+ for aprocess of fluid handling in which oneor more characteristics or conditionsof a fluent material are determined.

356, Optics: Measuring and Testing, sub-class 450 for interferometers and sub-classes 128+ for refractometers.

4 INCLUDING PURGING OF THE SYS-TEM:This subclass is indented under the class defini-tion. Processes combined with a step ofremoving a contaminant from the separatoryapparatus.

(1) Note. Usually a material, such as a gas,is passed through the apparatus toremove the contaminant.

SEE OR SEARCH CLASS:95, Gas Separation: Processes, sub-

classes 241+ for degasification of liq-uid.

134, Cleaning and Liquid Contact WithSolids, subclasses 1+ for a process ofseparating or removing adherentundesired matter from solid materialand subclasses 43+ for apparatus forcleaning by liquid contact.

137, Fluid Handling, subclasses 15.01through 15.26 for a process of clean-ing, repairing or assembling.

201, Distillation: Processes, Thermolytic, subclass 2 for a process of cleaningthe apparatus or removing adheringchar product.

5 SEPARATING ISOTOPES OR TAU-TOMERS:This subclass is indented under the class defini-tion. Processes directed to separating (1) theatoms of a given element or a compound con-taining said atoms according to the atomicweights of said atoms according to the atomicweights of said atoms or (2) a mixture contain-ing at least two tautomeric forms of a substanceinitially in a state of equilibrium.

(1) Note. A mixture of H2O and D2O is anexample of a feed mixture containinghydrogen atoms of different atomicweights.

(2) Note. Separating by distillation theketoenol forms of a compound is withinthe purview of this subclass.


classes 31+ for processes in which aplurality of gases is separated by mak-ing use of physical difference inweight.

423, Chemistry of Inorganic Compounds, subclass 580.1 for processes of pro-ducing water and subclass 580.2 forprocesses of producing heavy waterincluding a chemical reaction.


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6 ADDITION OF MATERIAL TO DISTIL-LAND TO INHIBIT OR PREVENT REAC-TION OR TO STABILIZE:This subclass is indented under the class defini-tion. Processes including adding an element ora chemical compound or mixture (of sub-stances) to the distilland or the vapor to inhibitor prevent formation of scale on the apparatusand/or to inhibit or prevent corrosion of theapparatus and/or to inhibit or prevent anunwanted reaction of the feed, vapor, residueor condensate.

(1) Note. The addition of a scale inhibitingmaterial to water being distilled or theaddition of a corrosion inhibiting mate-rial to an acidic material being distilledor the addition of a material which inhib-its the polymerization of an olefin at thetemperature of the distillation are non-limiting examples of the scope of thisand indented subclasses.

SEE OR SEARCH THIS CLASS, SUB-CLASS:86, for a separatory distillation process

including the use of a surface of a spe-cific composition which therebyinhibits or prevents an unwanted reac-tion.

SEE OR SEARCH CLASS:252, Compositions, subclasses 397+ for

compositions for preventing, inhibit-ing or reducing oxidation, chemicaldecomposition, or other chemicalchange.

260, Chemistry of Carbon Compounds, and its daughter Classes 530-570 for anonhydrocarbon organic compoundcontaining a stabilizer.

422, Chemical Apparatus and Process Dis-infecting, Deodorizing, Preserving, orSterilizing, subclasses 7+ for processof maintaining an environment nonde-structive to metal.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 1+ for a hydrocar-bon compound containing a stabilizer.

7 For scale inhibiting or corrosion preventing:This subclass is indented under subclass 6.Processes directed to adding a substance toinhibit or prevent corrosion of the apparatusand/or to inhibit or prevent scale formation.

SEE OR SEARCH CLASS:196, Mineral Oils: Apparatus, subclass 133

for a mineral oil vaporizer havingsome special feature of construction.

202, Distillation: Apparatus, subclass267.1 for apparatus in terms of thematerials of construction.

208, Mineral Oils: Processes and Products, subclass 47 for a process of treatingmineral oil including a step to preventor reduce corrosion or erosion of theapparatus employed in the processand see “SEARCH THIS CLASS,SUBCLASS” and “SEARCHCLASS” thereunder for related fieldsof search.

252, Compositions, subclasses 175+ forwater-softening or purifying or scale-inhibiting agents, and subclasses 387+for anti-corrosion agents.

8 For inhibiting or preventing a polymeriza-tion reaction:This subclass is indented under subclass 6.Processes directed to adding a substance toinhibit or prevent unwanted polymerization.

SEE OR SEARCH THIS CLASS, SUB-CLASS:30, for a separatory distillation process in

which a substance is added to cause adesired polymerization of at least onecomponent.

9 Of unsaturated hydrocarbon:This subclass is indented under subclass 8.Processes directed to inhibiting or preventingthe polymerization of an unsaturated hydrocar-bon.

10 WATER PURIFICATION ONLY:This subclass is indented under the class defini-tion. Processes of purifying water in which theonly material recovered as a product is water.


December 2009

SEE OR SEARCH CLASS:159, Concentrating Evaporators, sub-

classes 5+ for concentrating apparatusof the film type, subclasses 13.1+ forevaporating apparatus designed tomaintain the liquid being evaporatedin a film, and subclass 49 for an evap-orating process in which the liquid tobe concentrated is spread in a thinfilm.

165, Heat Exchange, appropriate sub-classes for a process of adding watervapor to air or removing water vaporfrom air.

202, Distillation: Apparatus, subclass 167for a separatory distillation apparatuswhich includes a still and a feed waterheater.

210, Liquid Purification or Separation, subclasses 600+ for a process of puri-fying a liquid not otherwise providedfor.

423, Chemistry of Inorganic Compounds, subclass 580.1 for processes of pro-ducing water and 580.2 for processesof producing heavy water including achemical reaction.

11 Under pressure or vacuum:This subclass is indented under subclass 10.Processes in which distillation is carried outunder a pressure greater than atmospheric orunder a vacuum.

SEE OR SEARCH THIS CLASS, SUB-CLASS:73+, for a plural distillation process in

which at least one distillation is underpressure or vacuum.

91+, for a single distillation process carriedout under pressure or vacuum.

12 DISTILLING TO SEPARATE ORREMOVE ONLY WATER:This subclass is indented under the class defini-tion. Processes in which only water isremoved from the feed mixture.

(1) Note. For purposes of this and indentedsubclasses water is the impurity of thedistilland which is to be removed. A pro-cess of removing other impurities as wellas water is excluded.

(2) Note. A plural distillation process of sep-arating only water by adding an extrane-ous liquid to the distilland to alter therelative volatility of water and the liquidbe dried in the initial distillation step andthen distilling a product of the initial dis-tilling operation to separate the extrane-ous liquid is classified here.

SEE OR SEARCH THIS CLASS, SUB-CLASS:10+, for a process in which the only mate-

rial recovered as a product is water.50+, for a process directed to adding a spe-

cific extraneous material to alter therelative volatility of a component of amixture.

SEE OR SEARCH CLASS:23, Chemistry: Physical Processes, sub-

class 306 for a process of concentrat-ing a solution of a liquid in a liquidnot otherwise provided for.

34, Drying and Gas or Vapor ContactWith Solids, appropriate subclasses,under “Processes” for a process forseparating a liquid from a solid.

62, Refrigeration, subclasses 93+ for aprocess of removing moisture fromair.

95, Gas Separation: Processes, appropri-ate subclasses for processes of remov-ing water from a gaseous fluidmixture. See particularly subclasses117+ for solid sorption processes toremove water from a gaseous fluidmixture and subclass 231 for pro-cesses of liquid contacting to removewater from a gaseous fluid mixture.

13 From nitric acid:This subclass is indented under subclass 12.Processes in which the liquid substance isaqueous nitric acid.

SEE OR SEARCH CLASS:423, Chemistry of Inorganic Compounds,

subclasses 390.1+ for producing nitricacid by a chemical reaction.


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14 From organic compound:This subclass is indented under subclass 12.Processes for separating water from an organiccompound.

(1) Note. Mixtures of organic substancesfrom which only water is separated by adistillation step are included in this andindented subclasses unless otherwiseprovided for.

SEE OR SEARCH CLASS:208, Mineral Oils: Processes and Products,

subclasses 187+ for a process forremoving water from mineral oils andsee “Note”, “SEARCH THIS CLASS,SUBCLASS” and “SEARCHCLASS” in subclass 187 for relatedprocesses for removing water fromorganic mixtures.

260, Chemistry of Carbon Compounds, appropriate subclasses for a processincluding removing water by distilla-tion combined with a step for forminga compound or extracting the com-pound from a natural source.

15 Organic acid:This subclass is indented under subclass 14.Processes in which the organic substance is anorganic acid.

(1) Note. The term “organic acid” includesorganic compounds which contain anacid function, e.g., boro, phosphor, sulfaor carboxylic group and see Class 260,Chemistry of Carbon Compounds, sub-class 500 “(1) Note”.

SEE OR SEARCH THIS CLASS, SUB-CLASS:14, for a separatory distillation process

for removing only water from salts oresters of organic acids.

16 Acetic:This subclass is indented under subclass 15.Processes in which the organic acid is aceticacid.

17 Aldehyde or ketone:This subclass is indented under subclass 14.Processes in which the organic substance is analdehyde or a ketone.

(1) Note. The terms “aldehyde” and“ketone” include those compounds hav-ing the structure R1COR2 wherein R1 ishydrocarbon and R2 is either hydrogenor hydrocarbon. See Class 568, OrganicCompounds, subclasses 303 and 420 andthe notes thereunder.

18 Alcohol:This subclass is indented under subclass 14.Processes in which the organic substance is analcohol.

(1) Note. For purposes of this and indentedsubclasses the term “alcohol” is limitedto a hydroxy group bonded to carbon.

19 Ethanol:This subclass is indented under subclass 18.Processes in which the alcohol is ethanol.

20 INCLUDING DEFOAMING OR INHIBIT-ING FOAM:This subclass is indented under the class defini-tion. Processes directed to defoaming or inhib-iting the formation of foam.

SEE OR SEARCH CLASS:95, Gas Separation: Processes, subclass

155 for processes of gas separationinvolving liquid contacting and theuse of a defoaming or antifoamingagent; subclass 157 for processes ofgas separation involving liquid con-tacting and defoaming the liquid; andsubclass 242 for defoaming a liquid,per se.

137, Fluid Handling, appropriate sub-classes for apparatus for controllingthe degree of foaming in a gascharged liquid.

201, Distillation: Processes, Thermolytic, subclass 9 for a process of surfacetreating the solid particles of thecharge to inhibit, reduce or preventfoaming during distillation.


December 2009

202, Distillation: Apparatus, subclass 264for distillation apparatus intended tobreak foam or inhibit foaming.

435, Chemistry: Molecular Biology andMicrobiology, subclass 266 for a fer-mentation process including the stepof treating the foam produced.

516, Colloid Systems and Wetting Agents;Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 115+ for pro-cesses of or compositions for or sub-combination compositions for thebreaking of or inhibiting of foam col-loid systems, when genericallyclaimed or when there is no hierarchi-cally superior provision in the USPCfor the specifically claimed art.

21 AND RECOVERING HEAT BY INDI-RECT HEAT EXCHANGE:This subclass is indented under the class defini-tion. Processes directed to recovering wasteheat by indirect heat exchange with (1) a dis-parate source or (2) a product of a distillationstep.

(1) Note. Heat generated by an engine whichruns a compressor used in the process isa disparate source of “waste heat” withinthe scope of this and indented sub-classes.

SEE OR SEARCH THIS CLASS, SUB-CLASS:100, for a digest of distillation processes

directed to specific type of heating.

SEE OR SEARCH CLASS:34, Drying and Gas or Vapor Contact

With Solids, subclasses 427 and 513for a process including conservingheat by indirect heat exchange.

62, Refrigeration, subclass 96 for a pro-cess in which heat from a gas beingcooled is transferred to a heatabsorber by indirect heat exchange,and subclass 113 for a process ofrefrigeration in which one function isin heat exchange relation with a sec-ond function.

165, Heat Exchange, appropriate sub-classes for heat exchange apparatus

and note Search Class under Classdefinition for related fields of search.

196, Mineral Oils: Apparatus, subclass 134for apparatus for vaporizing mineraloils including means for heat recoveryfrom the vapor or residuum.

202, Distillation: Apparatus, subclass 146for a horizontal retort with flueswherein the air and/or gas for com-bustion is heated by the waste prod-ucts of combustion by means of asingle-surface heater and subclass 150for a similar apparatus using a double-surface heater.

208, Mineral Oils: Processes and Products, subclass 365 for a process wherein themineral oil distilland is heated byindirect contact with a heated productof the distillation.

237, Heating Systems, appropriate sub-class for a heating system which mayuse the heat rejecting portion of arefrigeration system with additionalheating means.

261, Gas and Liquid Contact Apparatus, subclasses 158+ for apparatus forindirect interchange of heat betweencontact fluids.

22 Utilizing recovered heat for heating feed:This subclass is indented under subclass 21.Processes in which the feed is heated by therecovered waste heat.


With Solids, subclass 513 for a pro-cess of including the step of exchang-ing heat between the incoming andoutgoing gases.

196, Mineral Oils: Apparatus, subclass 134for mineral oil vaporizing apparatushaving means for preheating the oil bythe heat of the vapor or residue.

201, Distillation: Processes, Thermolytic, subclasses 14+ for a thermolytic dis-tillation process directed to using aconversion product as an indirectsource of heat for heating the feed.

202, Distillation: Apparatus, subclass 159for a distillation system including adevice for heating the feed with aproduct of the distillation step andsubclasses 177+ for a still system


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including a device for preheating thefeed with a product of the distillationstep.

23 Distillation residue as heat source:This subclass is indented under subclass 22.Processes in which distillation residue is thesource of recovered heat.


subclass 353 for a process whereinone component being distilled isheated by indirect heat exchange of acomponent of the process, usually bythe residue.

24 Compressed vapor as heat source:This subclass is indented under subclass 22.Processes in which compressed vapor is thesource of waste heat.

25 Utilizing recovered heat for heating the dis-tillation zone:This subclass is indented under subclass 21.Processes in which the distillation zone isheated by the recovered waste heat.

SEE OR SEARCH CLASS:202, Distillation: Apparatus, subclass 174

for multiple effect still series appara-tus, 187 for apparatus in which thestill and condenser are concentric and192 for apparatus to which the coolingliquid in the condenser passes to thestill to be distilled.

26 Compressed vapor as heat source:This subclass is indented under subclass 25.Processes in which the source of waste heat iscompressed vapor.

27 Utilizing recovered heat in subsequent stepin process:This subclass is indented under subclass 21.Processes in which the recovered waste heat isutilized in a step subsequent to the step inwhich the heat was produced.

28 WITH CHEMICAL REACTION:This subclass is indented under the class defini-tion. Processes including the step of producinga chemical reaction of a component of the mix-

ture being separated to facilitate separation ofthe desired substance in the original mixture.

(1) Note. To come within the purview of thisand indented subclasses a chemicalchange must occur which facilitates therecovery without chemical change of thedesired substance which was present inthe original mixture.


subclasses 46+ for a process of treat-ing mineral oil which results in achemical alteration of at least some ofthe hydrocarbon molecules thereof.

546, Organic Compounds, subclasses 134+for a general process of chemicallytreating a carbon compound not other-wise provided for.

588, Hazardous or Toxic Waste Destruc-tion or Containment, subclasses 300through 320 for the use of a chemicalreaction with distillation as part of aprocess of the destruction of hazard-ous or toxic waste.

29 Including step of adding catalyst or reactingmaterial:This subclass is indented under subclass 28.Processes directed to adding a catalyst or amaterial which reacts with a component of themixture to assist the separation of the desiredcomponent in the original mixture.

(1) Note. A chemical reaction for purposesof this and indented subclasses includessuch reactions as (1) forming hydrates,(2) adjusting of hydrogen ion concentra-tion, (3) polymerizing a component, (4)oxidizing or reducing a component orthe addition to the mixture being actedupon of an oxidizing or reducing agent,and (5) the forming of different sub-stances.

SEE OR SEARCH THIS CLASS, SUB-CLASS:50+, for adding a substance to alter the rel-

ative volatility of components of theincoming feed without specificallyproducing a new chemical compound.


December 2009

30 For polymerizing unwanted component:This subclass is indented under subclass 29.Processes in which the added material causesunwanted material in the feed to enter a reac-tion forming polymeric material.

SEE OR SEARCH CLASS:520, Synthetic Resins or Natural Rubbers,

subclasses 1+ for a process of poly-merizing, per se, and products result-ing therefrom.

530, Chemistry: Natural Resins or Deriva-tives; Peptides or Proteins; Lignins orReaction Products Thereof, sub-classes 211+ for a process polymeriz-ing, per se, and products resultingtherefrom.

554, Organic Compounds, subclasses 25through 29 for a process polymeriz-ing, per se, and products resultingtherefrom.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 502+ for olefinpolymerization processes; and sub-class 832 for a hydrocarbon purifica-tion process which involvespolymerization and depolymerization.

31 Oxidizing material:This subclass is indented under subclass 29.Processes directed to adding an oxidizing sub-stance.

(1) Note. This subclass is limited to incorpo-rating a substance which is stated to oxi-dize a part of the material being treatedor is a well-known oxidizing agent.

(2) Note. Nitric acid is classified here andcrossed to subclass 34.

SEE OR SEARCH CLASS:532, Organic Compounds, appropriate sub-

classes for a process of purification byan oxidative treatment of a particularcarbon compound.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 833+ for a purifi-cation process involving the additionof an oxidizing agent to a hydrocar-bon feedstock.

32 Reducing material:This subclass is indented under subclass 29.Processes directed to adding a reducing sub-stance.

(1) Note. This subclass is limited to incorpo-rating a substance which is stated toreduce a part of the material beingtreated or is a well known reducingagent, e.g., hydrogen.

SEE OR SEARCH CLASS:532, Organic Compounds, appropriate sub-

classes for a process of purifying by areductive treatment, of a particularcarbon compound.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 258+ and 841 forhydrogenative purification of hydro-carbons.

33 Inorganic salt containing oxygen in theanion:This subclass is indented under subclass 29.Processes in which the reactive material addedis a metal or ammonium salt of an inorganicoxygen containing acid.

(1) Note. This subclass takes acid, neutraland basic salts of oxygen containinginorganic acids, e.g., NaHSO4, Na2SO4,CuCO3, Cu(OH)2.

34 Acid:This subclass is indented under subclass 29.Processes in which the added material is anacid.

(1) Note. For purposes of this and indentedsubclasses the term “acid” includes inor-ganic compounds which contain hydro-gen as the cation and under subclass 15see (1) Note for definition of organicacids.

SEE OR SEARCH THIS CLASS, SUB-CLASS:33, for processes in which the reacting

material is a complex inorganic acidsalt, e.g., NaHCO3.


1December 2009

35 Phosphoric or sulfuric acid:This subclass is indented under subclass 34.Processes in which the acid is phosphoric orsulfuric.

36 Alkaline oxide or hydroxide:This subclass is indented under subclass 29.Processes in which the added material is analkaline oxide or an alkaline hydroxide.

(1) Note. This subclass is limited to theoxides and hydroxides of alkali metals,alkaline earth metals including magne-sium and the scandium group metals.

37 Alkali metal hydroxide:This subclass is indented under subclass 36.Processes in which the material is an alkalimetal hydroxide.

38 Organic material:This subclass is indented under subclass 29.Processes in which the added material isorganic.

(1) Note. To come within the purview of thissubclass an organic compound must beclearly disclosed to react with a compo-nent of the mixture being treated to forma new compound.

(2) Note. See class definition of Class 260,Chemistry of Carbon Compounds, forthe scope of the term “organic”.

(3) Note. A separatory distillation process ofadding an organic compound, such as analcohol or an acid, to form in situ anester which assists separation is classi-fied here and cross-referenced to theappropriate indented subclass under sub-class 57.

39 WITH DISPARATE PHYSICAL SEPARA-TION:This subclass is indented under the class defini-tion. Processes combined with subjecting thematerial being vaporized, the vapor, the distil-late or the residue to a disparate physical treat-ment to remove a substance.

(1) Note. A process merely including thestep of separating the immiscible layers

of the distillate, e.g., decanting, is notconsidered a disparate separation for thisand indented subclasses.

SEE OR SEARCH THIS CLASS, SUB-CLASS:50+, for a separatory distillation process

including the step of separating thedistillate layers in an azeotropic typedistillation and subclasses 76, 79, 83,85, 92+, and 95+, when the azeotro-ping agent is water only.


classes 293+ for a general physicalprocess not otherwise classified andunder subclass 293, see “SEARCHTHIS CLASS, SUBCLASS” and“SEARCH CLASS” for related fieldsof search.

95, Gas Separation: Processes, for pro-cesses of gas separation, per se.

201, Distillation: Processes, Thermolytic, subclasses 3+ for a process of physi-cal separating of a solid in theremoved by product mixture.

208, Mineral Oils: Processes and Products, subclass 369 for a process of distillingmineral oil involving some noncon-densation treatment of the volatilesevolved during distillation and sub-class 349 for a process in which theliquid condensate or the residueresulting from the distillation is sub-jected to a nonvaporizing treatment.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 802+ for hydro-carbon purification by plural serialdiverse separations.

40 Of entrained particles from a vapor or gas:This subclass is indented under subclass 39.Processes directed to removing entrained solidor liquid particles from gas or vapor in the dis-tillation operation.

SEE OR SEARCH CLASS:95, Gas Separation: Processes, for pro-

cesses, per se, of removing solid orliquid particles entrained in a gas.


December 2009

122, Liquid Heaters and Vaporizers, sub-class 492 for a device in the steamdome of a boiler for separating waterfrom steam.

137, Fluid Handling, subclasses 544+ forfluid handling apparatus includingmeans for separating solid materialfrom a fluid and see “SEARCH THISCLASS, SUBCLASS” and“SEARCH CLASS” under subclass544 for related fields of search.

202, Distillation: Apparatus, subclass 197for apparatus in which vapor depositsentrained solid or liquid particles.

209, Classifying, Separating, and Assort-ing Solids, subclasses 19 through 37 and 133+ for a process of using freesuspension in a gas or separating solidcomponents of a mixture.

41 Utilizing solid sorbent:This subclass is indented under subclass 39.Processes directed to material being treatedbeing acted upon with a solid sorbent to assistseparation of a desired product.

(1) Note. The sorbent must contact the dis-tilland during distillation or a product ofthe distillation step.


classes 90+ for processes, per se, ofgas separation utilizing solid sorption.

202, Distillation: Apparatus, subclass 200for distillation apparatus in which thevapor is passed through porous mate-rial or other porous material.

208, Mineral Oils: Processes and Products, subclass 310 for a process wherein amineral oil containing fluid is con-tacted with a solid sorptive material,and note “SEARCH THIS CLASS,SUBCLASS” and “SEARCHCLASS” thereunder.

210, Liquid Purification or Separation, subclasses 660+ for a process of puri-fying a liquid by sorption.

502, Catalyst, Solid Sorbent, or SupportTherefor: Product or Processes ofMaking, subclasses 60+ and 400+ fora sorbent composition.

42 Utilizing liquid sorption of component fromgas or vapor:This subclass is indented under subclass 39.Processes directed to extracting a componentfrom gas or vapor with a liquid.


classes 149+ for processes, per se, ofgas separation utilizing liquid contact-ing.

208, Mineral Oils: Processes and Products, subclass 311 for a process in whichmineral oil is mixed with a liquidwhich will form with a portion of theoil a liquid phase which is immisciblewith the rest of the oil and note“SEARCH THIS CLASS, SUB-CLASS” and “SEARCH CLASS”thereunder.

261, Gas and Liquid Contact Apparatus, appropriate subclasses for apparatusfor contacting a gas and a liquid.

532, Organic Compounds, appropriate sub-classes for a process including treat-ment for absorbing impurities.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 833+ for hydro-carbon purification by solvent extrac-tion.

43 Utilizing liquid-liquid extracting of distilla-tion product:This subclass is indented under subclass 39.Processes directed to extracting a liquid prod-uct of a distillation step with a liquid.

(1) Note. The extraction with a liquid musttake place subsequent to the vaporizationof the distilland. The liquid extractedmay be the initial distillate or residue ora product of a subsequent distillationoperation.


classes 306+ for process of concen-trating a liquid in liquid.

95, Gas Separation: Processes, subclass190 for processes, per se, of gas sepa-ration utilizing liquid contacting andseparation of liquid from the contactliquid by liquid-liquid extraction.


1December 2009

208, Mineral Oils: Processes and Products, subclasses 311+ for a process inwhich mineral oil is mixed with orcontacted with another liquid whichwill dissolve or is miscible with a por-tion or fraction of the oil and by sodoing forming a liquid phase which isimmiscible with another portion orfraction, particularly subclass 339 andunder subclass 311 see “SEARCHTHIS CLASS, SUBCLASS” and“SEARCH CLASS” for related fieldsof search.

210, Liquid Purification or Separation, subclasses 634+ for a process ofextracting a solute from a liquid solu-tion by contacting the solution with asecond liquid.

260, Chemistry of Carbon Compounds,and its daughter Classes 530-570appropriate subclasses for a process ofisolating or purifying a nonhydrocar-bon carbon compound including a liq-uid extraction step and for a processincluding extracting a carbon com-pound from a mixture.

423, Chemistry of Inorganic Compounds, appropriate subclasses for a process ofisolating or purifying an inorganiccompound by an extracting, leachingor dissolving step.

424, Drug, Bio-Affecting and Body Treat-ing Compositions, for a process ofproducing a composition of that classand which may include an extractionstep. See especially subclasses 123+,195.15-195.17, 520+, and 725-780.

426, Food or Edible Material: Processes,Compositions, and Products, sub-classes 425+ for extracting or using aliquid as an extracting medium.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 833+ for hydro-carbon purification by solvent extrac-tion.

44 Of distillate:This subclass is indented under subclass 43.Processes in which the extracted liquid is a dis-tillate.

45 And distilling raffinate phase:This subclass is indented under subclass 44.Processes directed to distilling the distillateafter it has been extracted with a liquid.

(1) Note. The raffinate phase is that part ofthe distillate which does not dissolve inthe extracting liquid during the liquidextraction step.

SEE OR SEARCH THIS CLASS, SUB-CLASS:74+, and 81+, for a plural separatory distil-

lation process in which the initial dis-tillate is distilled.

46 And distilling extractant phase:This subclass is indented under subclass 44.Processes directed to distilling the extractingliquid phase subsequent to the extraction step.

(1) Note. The extracting liquid phase is theliquid composed of the extracting liquidand the portion of the distillate solubletherein.

47 Utilizing removing solid from liquid:This subclass is indented under subclass 39.Processes directed to separating a solid mate-rial from a product of the distillation step.

SEE OR SEARCH CLASS:210, Liquid Purification or Separation,

subclasses 600+ for a process of sepa-rating a solid from a liquid, especiallysubclasses 702+ for an accretion orprecipitation process; and subclasses767+ for a skimming, settling, or fil-tration process.

48 By crystallizing:This subclass is indented under subclass 47.Processes directed to crystallizing a componentfrom a product of the distillation step.

(1) Note. The fact that the solid material iscrystalline must be stated in the claim.


classes 295+ for a process includingcrystallization and under subclass


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295, see “SEARCH CLASS” forrelated crystallization processes.

127, Sugar, Starch, and Carbohydrates, subclasses 58+ for a process of crys-tallizing sugar from a solution.

532, Organic Compounds, appropriate sub-classes for a process of physicallytreating an organic compound whichincludes the step of crystallizing.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 812+ for a hydro-carbon separation or purification pro-cess which includes chilling to form asolid.

49 CONVECTIVE DISTILLATION WITHNORMALLY GASEOUS MEDIUM, E.G.,AIR:This subclass is indented under the class defini-tion. Processes directed to passing through thematerial being distilled a normally gaseoussubstance.

(1) Note. A substance to be considered “nor-mally gaseous” must have a boilingpoint below - 10oC at atmospheric pres-sure. Air, ammonia, carbon dioxide,dimethyl ether and propane are someexamples of “normally gaseous” sub-stances.


class 307 for a process of concentrat-ing a solution of a liquid in a liquid inwhich the liquid being concentrated isdirectly contacted with the concentrat-ing medium (e.g., hot gases).

95, Gas Separation: Processes, sub-classes 263+ for degasification of aliquid by stripping with a gas.

202, Distillation: Apparatus, subclass 134for a retort having provision forinjecting a fluid for convective sepa-ration of the distillate.

208, Mineral Oils: Processes and Products, subclasses 356 and 362 for a processof distilling mineral oil in the pres-ence of an added gas or vapor, andsubclass 43 for a process of contactingtar with high temperature gas duringdistillation.

261, Gas and Liquid Contact Apparatus,appropriate subclasses for apparatusadapted to produce an intimate con-tact between gases and liquids, partic-ularly subclasses 121.1+ for devicesfor discharging gases beneath the sur-face of a liquid.

50 ADDING MATERIAL TO DISTILLANDEXCEPT WATER OR STEAM PER SE:This subclass is indented under the class defini-tion. Processes including the step of addingmaterial other than water or steam per se to thedistilland or distillation zone.

(1) Note. This subclass and indented sub-classes include azeotropic and extrac-tive distillations in which additionalmaterial other than water or steam aloneis added to alter the relative volatility ofcomponents of the distilland to assist thedistillative separation. Usually the mate-rial is added to the distilland or the distil-lation zone. Recycling all or part of aproduct of the distillation is not consid-ered adding an additional material forpurposes of this and indented subclasses.

(2) Note. The use of water or steam in addi-tion to the added material is within thescope of this and indented subclasses.

(3) Note. When two or more distinct speciesof added substance are claimed, thepatent is placed in the subclass first pro-viding for a species. When a speciesclaimed is not specifically provided for,the patent is placed in the generic sub-class (50 or 57) and cross-references tothe subclasses providing for the otherspecies.

(4) Note. See Class 260, Chemistry of Car-bon Compounds, class definitions, Defi-nition of Terms Employed in this Class,and appropriate subclasses for defini-tions of terms for organic compoundsused in this and indented subclasses.

SEE OR SEARCH THIS CLASS, SUB-CLASS:12+, for a process for reducing only the

water content of the distilland inwhich additional material assists the


1December 2009

distillative separation and subclasses76, 79, 83, 85, 92+, and 95+ for a sep-aratory distillation process in whichonly water or steam is the additionalmaterial added.

29+, for a separatory distillation process inwhich the added material reacts with acomponent of the material being sepa-rated or catalyzes a chemical reaction.

39+, for a distillation process in which anextraneous material is utilized toassist a disparate physical separationsuch as extraction or sorption.


subclasses 356 and 362 for a processof distilling mineral oil in the pres-ence of an added gas or vapor, andsubclass 313 for a process of distillingmineral oil in the presence of a selec-tive solvent. Under subclass 362 see“SEARCH THIS CLASS, SUB-CLASS” and “SEARCH CLASS” forrelated fields of search.

51 At least two materials:This subclass is indented under subclass 50.Processes in which plural materials are added.

(1) Note. Each of the added materials maybe repeatedly added to the distilland atdifferent points in the same distillationzone, for the purpose of this subclass.

(2) Note. When a series of distillations iscarried out and a different substance isadded in separate distillations, the pro-cess is treated as adding a single sub-stance and classified under subclass 50according to the claimed added sub-stance first appearing.

52 Mixtures of hydrocarbons:This subclass is indented under subclass 51.Processes in which a mixture of hydrocarbonsis added.

(1) Note. Benzine, gasoline and keroseneare examples of hydrocarbon mixtures.


subclasses 14+ for mineral oil mix-tures.

53 One material is water:This subclass is indented under subclass 51.Processes in which the additional materialcomprises water or stream and at least oneother substance.

(1) Note. For purposes of this and indentedsubclasses the plural component mix-ture added includes a solution, a suspen-sion, or water and at least one othersubstance added separately to produce acomplementary result.

54 A second material is aldehyde or ketone:This subclass is indented under subclass 53.Processes in which another substance com-prises an aldehyde or a ketone.

55 A second material is an alcohol:This subclass is indented under subclass 53.Processes in which the other substance com-prises an alcohol.

56 One additive an alcohol or ether:This subclass is indented under subclass 51.Processes in which the additional materialcomprises an alcohol or an ether and at leastone other substance.

57 Organic compound:This subclass is indented under subclass 50.Processes in which the additional material is anorganic compound.

(1) Note. See Class 260, Chemistry of Car-bon Compounds, Class Definitions, Def-initions of Terms Employed In ThisClass, and appropriate subclasses fordefinitions of terms used in this andindented subclasses.

SEE OR SEARCH CLASS:260, Chemistry of Carbon Compounds,

appropriate subclass for a particularnonhydrocarbon organic compound.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 16+ for a hydro-carbon compound per se, and sub-


December 2009

classes 864+ for hydrocarbonpurification involving use of anorganic agent.

58 Heterocyclic:This subclass is indented under subclass 57.Processes in which the organic compound isheterocyclic.

(1) Note. The term heterocyclic denotes thepresence of a ring whose members arecomposed of at least one carbon atomand one or more atoms of the elementstaken from the group consisting of nitro-gen, oxygen, sulfur, selenium and tellu-rium.

(2) Note. Carbohydrates and their deriva-tives unless shown to be acyclic are pre-sumed to be heterocyclic compounds.

SEE OR SEARCH THIS CLASS, SUB-CLASS:57, for a distillation process utilizing a

ring oregano boron or oregano phos-phorus compound.


subclasses 325+ for a process of frac-tionating mineral oil in which a het-erocyclic organic compound is aselective solvent.

59 Amine:This subclass is indented under subclass 57.Processes in which the organic compound is anamine.

(1) Compounds containing amino and otherfunctional groups are classified here andcross-referenced to the other functionalgroups appearing below.

60 Ester:This subclass is indented under subclass 57.Processes in which the organic compound is anester.

(1) Note. For purposes of this subclass theterm “ester” includes amide and nitrite.


which an organic acid or an alcohol isadded to form in situ an ester whichaids separation by changing the rela-tive volatility of components of thedistilland.

61 Acid:This subclass is indented under subclass 57.Processes in which the organic compound is anacid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:15, for the scope of the term “and”.

62 Aldehyde or ketone:This subclass is indented under subclass 57.Processes in which the organic compound is analdehyde or a ketone.

SEE OR SEARCH THIS CLASS, SUB-CLASS:17, for the meaning of “aldehyde” and

“ketone”.

63 Alcohol or ether:This subclass is indented under subclass 57.Processes in which the compound is an alcoholor an ether.

(1) Note. As used in this and indented sub-classes the term “alcohol” includes themonohydroxy and polyhydroxy organiccompounds such as: butanol, glycol,glycerol, sorbitol, cyclohexanol, phenol,(ROH).

(2) Note. As used in this and indented sub-classes the term “ether” includes organiccompounds in which the hydrogen of atleast one alcohol group has beenreplaced by a hydrocarbon radical.

SEE OR SEARCH THIS CLASS, SUB-CLASS:57, for a process using a mercaptan (thiol

alcohol) or an organic sulfide (thiolether) without other significantgroups.


1December 2009

59, for a process in which the added mate-rial is an amino alcohol.

64 Polyhydroxy alcohol or ether derivativethereof:This subclass is indented under subclass 63.Processes in which the compound is polyhy-droxy alcohol or an ether derivative thereof.

65 Hydroxy aromatic (e.g., Phenol):This subclass is indented under subclass 63.Processes in which the organic compound is ahydroxy aromatic, e.g., phenol, naphthol,cresol.

66 Methanol:This subclass is indented under subclass 63.Processes in which the alcohol is methanol.

67 Halogenated hydrocarbon:This subclass is indented under subclass 57.Processes in which the compound is a haloge-nated hydrocarbon.

(1) Note. Organic compounds which containonly carbon, hydrogen and halogen arehalogenated hydrocarbons.

SEE OR SEARCH CLASS:570, Organic Compounds, subclasses 101+

for compounds which contain halogenbonded to carbon.

68 Hydrocarbon:This subclass is indented under subclass 57.Processes in which the compound is a hydro-carbon.

(1) Note. For purposes of this and indentedsubclasses the term “hydrocarbon” islimited to compounds consisting of car-bon and hydrogen.

SEE OR SEARCH THIS CLASS, SUB-CLASS:12+, for a process of separating only water

in which a hydrocarbon is the azeotro-ping agent.

43+, for a process in which the extractingliquid is a hydrocarbon.

52, for a process of adding a mixture ofhydrocarbons to assist separation dur-ing distillation.


subclass 337 for a process of fraction-ating mineral oil using a hydrocarbonas a solvent.

585, Chemistry of Hydrocarbon Com-pounds, appropriate subclasses forcompounds which consist of carbonand hydrogen only.

69 Aromatic:This subclass is indented under subclass 68.Processes in which the hydrocarbon is aro-matic.

(1) Note. A compound consisting of carbonand hydrogen characterized by the pres-ence of a benzene nucleus is an aromatichydrocarbon.

SEE OR SEARCH CLASS:585, Chemistry of Hydrocarbon Com-

pounds, subclasses 16 and 18 for ahydrocarbon which contains a ben-zene nucleus.

70 Acyclic:This subclass is indented under subclass 68.Processes in which the hydrocarbon is acyclic.

(1) Note. A compound consisting of carbonand hydrogen and having an open chainstructure, only, is an acyclic hydrocar-bon.

SEE OR SEARCH CLASS:585, Chemistry of Hydrocarbon Com-

pounds, subclasses 16 and 18 for ahydrocarbon which is acyclic.

71 PLURAL DISTILLATIONS PERFORMEDON SAME MATERIAL:This subclass is indented under the class defini-tion. Processes directed to utilizing at leasttwo distilling operations to separate compo-nents present in the original mixture.

(1) Note. The second distilling operationmay be performed on all or a part of adistillate, a side stream or a residue fromthe initial distilling operation.


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(2) Note. For purposes of this and indentedsubclasses an operation is considered tobe a plural operation if (a) a part of a dis-tilland is removed by distillation and theresidue in the still is further distilledunder a different pressure or with theaddition or absence of water or steamand (b) two or more distillation systemsare used regardless as to whether there isan intermediate condensation.

SEE OR SEARCH THIS CLASS, SUB-CLASS:21+, for a plural distillation process in

which useful heat is recovered byindirect heat exchange.

43, for a plural distillation process inwhich a residue of a distillation opera-tion is extracted with a liquid.

44+, for a plural distillation process inwhich a distillate of a distillationoperation is extracted with a liquid.



159, Concentrating Evaporators, sub-classes 47.1+, for a process of con-centrating a liquid, and see “SEARCHCLASS” thereunder for related fieldsof search.

196, Mineral Oils: Apparatus, subclasses105+ for a plurality of interconnectedmineral oil vaporizers.

202, Distillation: Apparatus, subclasses154 and 155 for separatory distillationapparatus having plural columns and/or plural stills and subclass 173 for aplurality of stills so connected thateither the vapor or the residue of oneflows into the other.

208, Mineral Oils: Processes and Products, subclasses 354+ and 364+ for a pro-cess of distilling mineral oil whereinthe vaporization is carried out in aplurality of separate and distinct oper-ations.

72 One a filming distillation:This subclass is indented under subclass 71.Processes in which at least one distilling opera-tion is directed to introducing the distilland intothe vaporization zone by spreading it as a thinfilm over a surface.

(1) Note. The surface on which the distillandis spread may be liquid, solid or forami-nous.

SEE OR SEARCH THIS CLASS, SUB-CLASS:89, for a process involving a single distil-

lation operation in which the distil-land is spread as a thin film over asurface.


classes 5+ for concentrating apparatusof the film type including subclasses13.1+ for evaporating apparatusdesigned to maintain the liquid beingevaporated in a film and subclass 49for an evaporating process in whichthe liquid to be concentrated is spreadin a thin film.

196, Mineral Oils: Apparatus, subclass 128for vaporizing apparatus for distillingmineral oil in a thin film.

202, Distillation: Apparatus, subclass 236for separatory distillation apparatus inwhich the still has means for intro-ducing the distilland into the still inthe form of a spray or the distilland isintroduced into the still in the form ofa film.

208, Mineral Oils: Processes and Products, subclass 360 for a process of distillingmineral oil wherein the oil is spread asa thin film on a surface.

73 One a distillation under positive pressure orvacuum:This subclass is indented under subclass 71.Processes in which at least one distillationoperation is carried out under a pressure greaterthan atmospheric or under a vacuum.


1December 2009

SEE OR SEARCH THIS CLASS, SUB-CLASS:43, for a distillation separatory process in

which the initial residue is extractedwith a liquid.

91+, for a single distillation process carriedout at a pressure greater or less thanatmospheric pressure and see“SEARCH CLASS” under subclass91 for related fields of search.

SEE OR SEARCH CLASS:202, Distillation: Apparatus, subclass 205

for a separatory distillation systemprovided with means for producing avacuum therein.

74 Distillation of initial distillate:This subclass is indented under subclass 73.Processes in which at least a portion of the dis-tillate from the initial distillation operation issubjected to at least one subsequent distillationoperation.

SEE OR SEARCH THIS CLASS, SUB-CLASS:45, and 46, for a process of separatory

distillation including extracting a dis-tillate with an immiscible liquid.

75 And return of distillation product to a previ-ous distillation zone:This subclass is indented under subclass 74.Processes in which a product from a later distil-lation operation is returned in terms of the pro-cess to a distillation zone prior to thedistillation zone in which the product was pro-duced.

(1) Note. The prior distillation zone must bein the series of distillation operationswhich produced the product beingreturned.

(2) Note. The product returned may be all ora part of a product of a second or subse-quent distillation operation in a series.

SEE OR SEARCH CLASS:165, Heat Exchange, subclasses 104.21+

for apparatus in which liquid is vapor-ized at one zone, condensed at another

and the condensate is returned to thefirst zone.

196, Mineral Oils: Apparatus, subclass 99for mineral oil distilling apparatusincluding the combination of a vapor-izer, condensing means with meansfor returning a part or all of the con-densate to the vaporizer.

208, Mineral Oils: Processes and Products, subclass 355 for a process of subject-ing mineral oil to at least two distilla-tion operations in which either vapors,condensate, and/or residue from alater distillation zone is returned to anearlier distillation zone.

76 Including the addition of water or steam:This subclass is indented under subclass 74.Processes directed to adding water or steam toat least one distillation operation.

(1) Note. Water or steam is usually added tothe distillation operation to change therelative volatility of the components ofthe material being distilled.

77 Initial distillation under positive pressure orvacuum:This subclass is indented under subclass 74.Processes in which the initial distillation is car-ried out under a pressure greater than atmo-spheric or under a vacuum.

78 And returning distillation product to a pre-vious distillation zone:This subclass is indented under subclass 73.Processes in which a product from a later distil-lation operation is returned in term of the pro-cess to a distillation zone prior to thedistillation zone in which the product was pro-duced.


for mineral oil distilling apparatusincluding the combination of a vapor-izer, condensing means with meansfor returning a part or all of the con-densate to the vaporizer.

208, Mineral Oils: Processes and Products, subclass 355 for a process of subject-ing mineral oil to at least two distilla-tion operations in which either vapors,condensate, and/or residue from a


December 2009

later distillation zone is returned to anearlier distillation zone.



SEE OR SEARCH THIS CLASS, SUB-CLASS:95+, for a single distillation process in

which water is added and under sub-class 95, see “SEARCH CLASS” forrelated fields of search.

80 Initial distillation under positive pressure orvacuum:This subclass is indented under subclass 73.Processes in which the initial distillation is car-ried out under a pressure greater than atmo-spheric or under a vacuum.

SEE OR SEARCH THIS CLASS, SUB-CLASS:77, for a process including the step of dis-

tilling the initial distillate in which theinitial distillation is under a pressuregreater or less than atmospheric pres-sure.

81 Distillation of initial distillate:This subclass is indented under subclass 71.Processes directed to distilling all or a part ofthe distillate from the initial distillation opera-tion.

(1) Note. The term “distillate” includes theportion of the incoming feed which istaken off “overhead” or taken off as a“side stream”.



45, and 46, for a plural distillation processincluding extracting a distillate with a

liquid and distilling the raffinatephase or the extractant phase.

82 And returning distillation product to a pre-vious distillation zone:This subclass is indented under subclass 81.Processes including returning a product from asecond or subsequent distillation operation in aseries to an earlier distillation in the series.


for mineral oil distilling apparatusincluding the combination of a vapor-izer, condensing means with meansfor returning a part or all of the con-densate to the vaporizer.

208, Mineral Oils: Processes and Products, subclass 355 for a process of subject-ing mineral oils to at least two distilla-tion operations including returningvapor, condensate, and/or residuefrom a later distillation to an earlierdistillation zone.



84 And returning distillation product to a pre-vious distillation zone:This subclass is indented under subclass 71.Processes which includes returning a productfrom a later distillation operation to a distilla-tion zone prior to the distillation zone in whichthe product was produced.



75, 78, 82, for other plural distillationprocesses in which at least a portionof a product of a second or subsequentdistillation step is returned to a distil-lation zone prior to the one in whichthe product was produced and sub-


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class 98, in which a separated productof a single separatory distillationoperation is returned to the distillationzone.


for mineral oil distilling apparatusincluding the combination of a vapor-izing and condensing means withmeans for returning a part or all of thecondensate to the vaporizer.

208, Mineral Oils: Processes and Products, subclass 355 for processes in whichmineral oil is subjected to at least twodistillation operations in which eithervapors, condensate, and/or residuefrom a later distillation zone isreturned to an earlier distillation zone.




72, 76, 79, and 83, for other plural distil-lation processes in which water orsteam is added.

95+, for a single distillation process inwhich water or steam is added.

86 DISTILLATION IN APPARATUS ORELEMENT OF SPECIFIC MATERIAL:This subclass is indented under the class defini-tion. Processes directed to distilling in a sys-tem in which all or a part thereof is recited asbeing made of a specific material.

(1) Note. Processes within the purview ofthis subclass must recite only a singledistillation step in which the composi-tion of the system or a part thereof isrecited. For example, broadly distillingusing a glass column.

(2) Note. The mere recitation in a claim thatan apparatus is metal does not bring itwithin the purview of this subclass, butthe recitation in the claim that the col-

umn filling material is chrome steel ballsor beryl saddles does.

SEE OR SEARCH THIS CLASS, SUB-CLASS:6+, for a process of adding a material to

inhibit or prevent chemical changewhich may or may not function tocoat the system.

SEE OR SEARCH CLASS:55, Gas Separation, subclasses 522+ for

gas separation apparatus in which thecomposition of the apparatus isrecited.

106, Compositions: Coating or Plastic, appropriate subclass for a composi-tion for coating the surfaces of the dis-tilling apparatus.

196, Mineral Oils: Apparatus, subclass 133for a mineral oil vaporizing systemhaving some special feature of con-struction.

201, Distillation: Processes, Thermolytic, subclass 18 for a process of destruc-tive distillation utilizing apparatus ofa particular composition.

202, Distillation: Apparatus, subclasses267.1+, in which the apparatus isrecited in terms of the materials ofconstruction.

266, Metallurgical Apparatus, subclasses280+ for the lining construction formetallurgical receptacles.

520, Synthetic Resins or Natural Rubbers, subclasses 1+ for a synthetic resin or acomposition containing a syntheticresin for coating distilling apparatus.

87 WITH FRACTIONAL CONDENSATIONOF VAPOR OUTSIDE STILL:This subclass is indented under the class defini-tion. Processes directed to condensing thevapor evolved during the distillation step in aplurality of fractions.

(1) Note. To come within the purview of thissubclass a mixed vapor must be pro-duced which is separated into parts bycooling the vapor in a plurality of dis-tinct stages.


December 2009

SEE OR SEARCH CLASS:201, Distillation: Processes, Thermolytic,

subclass 30 for a thermolytic distilla-tion process in which the evolvedvapors are condensed in a plurality ofdistinct stages.

202, Distillation: Apparatus, subclass 199for apparatus in which vapor is passedthrough a condensate from itself tosurrender high boiling constituents.

208, Mineral Oils: Processes and Products, subclass 342 for a process includingfractionally condensing a mineral oilcontaining vapor mixture.

88 FLASH VAPORIZATION OF DISTIL-LAND:This subclass is indented under the class defini-tion. Processes directed to heating the distil-land under pressure high enough to preventebullition and the heated distilland is thenintroduced into a zone of lesser pressure result-ing in the volatilizing of at least a portion of thedistilland.


classes 2.1+ for a flash evaporator.202, Distillation: Apparatus, subclass 177

for a separatory still with a preheater.208, Mineral Oils: Processes and Products,

subclass 352 and 361 for a process ofseparating mineral oil wherein the dis-tilland is heated under pressure highenough to prevent ebullition and theheated distilland is then introducedinto a zone of lesser pressure.

89 FILMING OF DISTILLAND FOR VAPOR-IZATION:This subclass is indented under the class defini-tion. Processes directed to introducing the dis-tilland into the vaporization zone by spreadingit as a thin film over a surface.

(1) Note. The surface on which the distillandis spread may be liquid, solid or forami-nous.


classes 5+ for concentrating apparatusof the film type including subclasses

13+ for evaporating apparatusdesigned to maintain the liquid beingevaporated in a film and subclass 49for an evaporating process in whichthe liquid to be concentrated is spreadin a thin film.

196, Mineral Oils: Apparatus, subclass 128for vaporizing apparatus for distillingmineral oil in a thin film.

202, Distillation: Apparatus, subclass 236for separatory distillation apparatus inwhich the still has means for intro-ducing the distilland into the still inthe form of a spray or in the form of afilm.

208, Mineral Oils: Processes and Products, subclass 360 for a process of intro-ducing mineral oil into the vaporiza-tion zone by spreading it as a thin filmover a surface. See also “SEARCHCLASS” thereunder for related fieldsof search.

90 SPRAYING OF DISTILLAND INTOVAPORIZATION ZONE:This subclass is indented under the class defini-tion. Processes directed to spraying the distil-land into the vaporization zone.


which heated distilland under pressureis introduced into a zone of lesserpressure resulting in the volatilizationof at least a portion of the distilland.


classes 48.1+ for a process for con-centrating in which the liquid beingconcentrated is reduced to a spray;and subclasses 3+ for concentratingapparatus of the spray type.

202, Distillation: Apparatus, subclass 236for separatory distillation apparatus inwhich the still has means for introduc-ing the distilland into the still in theform of a spray.

208, Mineral Oils: Processes and Products, subclass 359 for a process of distillingmineral oil in which the distilland issprayed into the vaporization zone


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and see “SEARCH CLASS” thereun-der for related fields of search.

91 VAPORIZATION ZONE UNDER POSI-TIVE PRESSURE OR VACUUM:This subclass is indented under the class defini-tion. Processes in which distillation is carriedout under a pressure greater than atmosphericor under a vacuum.

(1) Note. The use of pressure varying fromatmospheric changes the relative volatil-ity of the components of the distillandthereby altering the composition of thevapor evolved.


With Solids, subclasses 402+ for aprocess of drying a solid involving theapplication of a vacuum.

196, Mineral Oils: Apparatus, subclass 114for mineral oil vaporizing apparatusoperated under vacuum.

201, Distillation: Processes, Thermolytic, subclass 35 for a process of applyingdifferential pneumatic pressure to thethermolytic conversion zone.

202, Distillation: Apparatus, subclass 205for separatory distillation apparatusprovided with means for producing avacuum therein and see “SEARCHCLASS” thereunder for related fieldsof search.

208, Mineral Oils: Processes and Products, subclasses 357 and 366 for a processof distilling mineral oil in which thevaporization zone is under a pressuregreater or less than atmospheric pres-sure and see “SEARCH CLASS”under subclass 357 for related fieldsof search.

588, Hazardous or Toxic Waste Destruc-tion or Containment, subclasses 300through 321 for the use of heat orvacuum in the destruction of hazard-ous or toxic waste.

92 Including the addition of water or steam:This subclass is indented under subclass 91.Processes directed to adding water or steam tothe distillation operation.


93 And returning product of distillation step todistillation zone: This subclass is indented under subclass 92.Processes directed to returning a product to thedistillation zone.


for mineral oil distilling apparatusincluding the combination of vaporiz-ing and condensing means with meansfor returning a part or all of the con-densate to the vaporizer.

94 And returning product of distillation step todistillation zone: This subclass is indented under subclass 91.Processes directed to returning a product of thedistillation operation to the distillation zone.

(1) Note. To be considered a product of dis-tillation for purposes of this subclass anoverhead vapor or side stream must becondensed to a liquid before beingreturned to the distillation zone. In otherwords to be considered a “product” thesubstance must be isolated outside thedistillation zone.


subclass 358 for a mineral oil distilla-tion process in which condensate orresidue is returned to the rectificationzone after having been removed there-from to assist in the separation pro-cess.

95 INCLUDING ADDITION OF WATER ORSTEAM:This subclass is indented under the class defini-tion. Processes directed to adding water orsteam to the distillation operation.



December 2009


and 127 for mineral oil vaporizingapparatus having means to inject gasor vapor into the vaporization zone.

208, Mineral Oils: Processes and Products, subclasses 348, 356 and 362+ for aprocess in which a gas or vapor isemployed to affect volatilization ofthe distilland.

588, Hazardous or Toxic Waste Destruc-tion or Containment, subclass 312wherein the use of water or steam isused in the destruction of hazardousor toxic waste.

96 To distillation column:This subclass is indented under subclass 95.Processes in which the water or steam is addedto the distillation column.

97 And returning product of distillation step todistillation zone:This subclass is indented under subclass 95.Processes in which a product of the distillationoperation is returned to the distillation zone.



for mineral oil distilling apparatusincluding the combination of vaporiz-ing and condensing means with meansfor returning a part or all of the con-densate to the vaporizer.

208, Mineral Oils: Processes and Products, subclass 358 for a mineral oil distilla-tion process in which condensate orresidue is returned to the rectificationzone after having been removed there-from to assist in the vaporization pro-cess.

98 AND RETURNING PRODUCT OF DIS-TILLATION STEP TO DISTILLATIONZONE:This subclass is indented under the class defini-tion. Processes directed to returning a productof the distillation operation to the distillationzone.


SEE OR SEARCH THIS CLASS, SUB-CLASS:165, Heat Exchange, subclasses 104.21+

apparatus in which liquid is vaporizedin one zone, condensed in another andthe condensate is returned to the firstzone.

196, Mineral Oils: Apparatus, subclass 99for mineral oil distilling apparatusincluding the combination of vaporiz-ing and condensing means and meansfor returning a part or all of the con-densate to the vaporizer.

208, Mineral Oils: Processes and Prod-ucts, subclass 358 for a mineral oildistillation process in which conden-sate or residue is returned to the recti-fication zone after having beenremoved therefrom to assist in thevaporization process.

99 MISCELLANEOUS SEPARATORY:This subclass is indented under the class defini-tion. Processes not otherwise provided for.

(1) Note. In this subclass are distillationcombinations not provided for above andnot provided for elsewhere.




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99, Foods and Beverages: Apparatus, subclass 78 for a process of preparinga beverage base in concentrated fromand see “SEARCH THIS CLASS,SUBCLASS” and “SEARCHCLASS” thereunder for related fieldsof search.

159, Concentrating Evaporators, sub-classes 47.1+ for a process of concen-trating a liquid, and see “SEARCHCLASS” thereunder for related fieldsof search.

208, Mineral Oils: Processes and Products, subclass 347 for a process of distillingmineral oil not otherwise providedfor.

264, Plastic and Nonmetallic Article Shap-ing or Treating: Processes, subclasses405+ for a process directed to apply-ing electrical or wave energy directlyto the work.

426, Food or Edible Material: Processes,Compositions, and Products, appro-priate subclasses for a process of pre-paring a beverage base inconcentrated form.

CROSS-REFERENCE ART COLLECTIONS

The following subclass represents at least a substantialcollection of patents found elsewhere in the classifica-tion of this class which merit isolation for search aidpurposes on specific types of heating.

100 PARTICULAR TYPE OF HEATING:This subclass is indented under the class defini-tion. Processes as provided for in this classwherein there is recited or disclosed a referenceto a special type of heating, such as separationof the vapor by the heating effect of sonicwaves of a specific frequency.


classes 29+ for processes of gas sepa-ration in which the separation iseffected or enhanced by use of soundwaves.

165, Heat Exchange, appropriate sub-classes for apparatus and processesfor the transfer of heat from one mate-rial to another and see “SEARCHCLASS” under the class definition forrelated fields of search.

196, Mineral Oils: Apparatus, subclasses120+ for mineral oil vaporizing appa-ratus having special means for heat-ing.

202, Distillation: Apparatus, subclass 234for distillation apparatus using radiantheat or electric heating elements.

210, Liquid Purification or Separation, subclass 738 for a process of separat-ing liquid mixtures using pulsations oroscillations.

432, Heating, subclasses 1+ for a processof heating or heater, operation notelsewhere provided for.

END

Documents

December 2009 CLASSIFICATION DEFINITIONS 203 … of preparing alcoholic beverages includ-ing distillation. 532, ... FRACTIONAL DISTILLATION A separatory distillation operation in which