15
19 Effect of LAB composition on LAS performance Chlorina1ion Paraffin Chlomparaffin LAB (high 2-phenyllhigh dialkyhelralin) + Aiel} catalyst benzene L inear alkylbenzene sulfonate (LAS) continues 10 be the most widely used surfactant in the world. Currently. on a global basis. more than four billion pounds of lin- ear alkylbenzene (LAB). the feedstock used 10 make LAS. are consumed annually. In addition. several new plants are under construction in the world today. The popularity of LAS is simple to explain: LAS has an exceptional cost- performance profile. and has proven human safety and environmental acceptability. However. there is some uncenainty related to LAS in terms of understanding how variations in struc- rure impact performance. There are two reasons for this confusion: (a) for- mulations have become more concen- trated. which effectively magnifies differences in the formulatability among commercial products. and (b) new technologies have been devel- oped to manufacture LAB which have a greater variation in composition. The purpose of this article is to clarify how commercial LABs can vary in composition. and how these variations affect the performance of LAS. Introduction The LAB molecule consists of a linear paraffin chain attached to a benzene ring (Figure I). Commercial LAB. however. con- sists of a blend of LAB molecules that vary in terms of paraffin chainlength, Dehydrogenalion Paraffin I SURFACTANTS & DETERGENTS This article was prepared for INFORM by Michad F. Cox and Dewey L. Smith, Condea Vista Co.. 12024 Visla Parke Dr.. Austin. TX 78726. ........ position of the benzene ring along the paraffin chain, and concentration of a coproduct called dialkyltetralin. These variations in composition remain intact when LAB is sulfonated to form the finished surfactant, LAS. The most important factor in terms of LAB composition is average molecular weight. Increasing the average molecular weight increases surface activity and solution viscosi- ty, but decreases water solubility and water hardness tolerance. The inverse is true when average motecu- tar weight is decreased. Optimal average molecular weight depends largely on use conditions (such as temperature, water hardness, and concentration). The second-most important factor in relating LAB composition to LAS performance is the concentration of dialkyltetralin (OAT). OAT sulfonates readily and completely to form dialkyltetralin sulfonate (OATS). OATS aCIS as a surfactant. a hydrcrrope, and a viscosity modifier. Consequently, high OAT-containing LAB (with 6-10% OAT) is preferred for LAS intended for liquid formula- tions because less (or no) additional hydrotrope is required to achieve desired solubility and viscosity. Because OATS is nearly as surface- active as LAS itself, the presence of OAT in LAB has little effect on LAS performance. The distribution of phenyl isomers contained within a commercial LAB Figure 1. Linear alkylbenzene (one po .. l- ble Isomer ot dodecylbenzene) LAB (low 2-phenylllow diaJkyhetraJin) HFcalalyst Olefin (-,""',...,,...,.,.. + Solid alkylation benzene catalysl LAB (high 2-phenylllow dialkyltetralin) LAB (high 2-phenylllow dialkylteuaJin) Figure 2. Commereial processes tOl" LAB production INFORM. Vol. 8. no. I (January 199n

LAB Comp and LAS Performance

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Page 1: LAB Comp and LAS Performance

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Effect of LAB composition on LAS performance

Chlorina1ionParaffin • Chlomparaffin • LAB (high 2-phenyllhigh dialkyhelralin)

+ Aiel} catalystbenzene

Linear alkylbenzene sulfonate(LAS) continues 10 be the mostwidely used surfactant in the

world. Currently. on a global basis.more than four billion pounds of lin-ear alkylbenzene (LAB). the feedstockused 10 make LAS. are consumedannually. In addition. several newplants are under construction in theworld today.

The popularity of LAS is simple toexplain: LAS has an exceptional cost-performance profile. and has provenhuman safety and environmentalacceptability. However. there is someuncenainty related to LAS in terms ofunderstanding how variations in struc-rure impact performance. There aretwo reasons for this confusion: (a) for-mulations have become more concen-trated. which effectively magnifiesdifferences in the formulatabilityamong commercial products. and (b)new technologies have been devel-oped to manufacture LAB which havea greater variation in composition.

The purpose of this article is toclarify how commercial LABs canvary in composition. and how thesevariations affect the performance ofLAS.

IntroductionThe LAB molecule consists of a linearparaffin chain attached to a benzenering (Figure I).

Commercial LAB. however. con-sists of a blend of LAB molecules thatvary in terms of paraffin chainlength,

DehydrogenalionParaffin I

SURFACTANTS & DETERGENTS

This article was prepared forINFORM by Michad F. Coxand Dewey L. Smith, CondeaVista Co.. 12024 Visla ParkeDr.. Austin. TX 78726. ........

position of the benzene ring along theparaffin chain, and concentration of acoproduct called dialkyltetralin. Thesevariations in composition remain

intact when LAB is sulfonated to formthe finished surfactant, LAS.

The most important factor interms of LAB composition is averagemolecular weight. Increasing theaverage molecular weight increasessurface activity and solution viscosi-ty, but decreases water solubility andwater hardness tolerance. Theinverse is true when average motecu-

tar weight is decreased. Optimalaverage molecular weight dependslargely on use conditions (such astemperature, water hardness, andconcentration).

The second-most important factorin relating LAB composition to LASperformance is the concentration ofdialkyltetralin (OAT). OAT sulfonatesreadily and completely to formdialkyltetralin sulfonate (OATS).OATS aCIS as a surfactant. ahydrcrrope, and a viscosity modifier.Consequently, high OAT-containingLAB (with 6-10% OAT) is preferredfor LAS intended for liquid formula-tions because less (or no) additionalhydrotrope is required to achievedesired solubility and viscosity.Because OATS is nearly as surface-active as LAS itself, the presence ofOAT in LAB has little effect on LASperformance.

The distribution of phenyl isomerscontained within a commercial LAB

Figure 1. Linear alkylbenzene (one po .. l-ble Isomer ot dodecylbenzene)

LAB (low 2-phenylllow diaJkyhetraJin)HFcalalyst

Olefin (-,""',...,,...,.,..+ Solid alkylation

benzene catalysl

LAB (high 2-phenylllow dialkyltetralin)

LAB (high 2-phenylllow dialkylteuaJin)

Figure 2. Commereial processes tOl" LAB production

INFORM. Vol. 8. no. I (January 199n

Page 2: LAB Comp and LAS Performance

20

SURFACTANTS & DETERGENTS

"'~~----;::::=:===;-]• CII-Avg. LAS

• C1rAvg. LAS

... C13-Avg. LAS

Coocenlnltion of LAS [Jog C (gIL)] (increases from lefllo right)

Figure 3. Surface tension (at 2S"C, with 0.01 M N~O.,to buffer ionic strength).I.functlon of concentration for C,,-average LAS, C1z-lIVI!ntge LAS, and C13-eYeflIge LAS

8000

700l

6000

"5000'"l4000

" 300l

200l

100l

0II 12

Average LAS carbon chainlenglh

Figure 4. The effect 01 molecular weight on viscosity (25% LAS, 30·C, shear rete ..5 •• e-1)

also can influence solubility and vis-cosity, because it affects the way LASmolecules pack together in solution. Ahigher concentration of the 2- and 3-phenyl isomers generally improvesLAS solubility. Although the effect ofphenyl isomer distribution is smaller inmagnitude compared to the effect ofOATS, it can be significant. particular-ly when LAS concentration is high. orin the presence of high ionic strength.

Although understanding the rela-tionship between LAB compositionand LAS performance is important inobtaining maximum cost-effective-ness. such understanding also is diffi-cult because several variables areinvolved. and the effect of these vari-ables depends on the conditions underwhich the LAS is being used.

Why variations occurManufacture of LAB is accomplishedby connecting a paraffin chain 10 abenzene molecule. Chemically, this isachieved through the Friedel-Craftsalkylation of benzene withchloropar affins or olefins and analkylation catalyst. Although manypossible catalysts could be used, onlythree are used commercially: alu-minum chloride (AlCI). hydrofluoricacid (HF), and a newly patented solidalkylation catalyst (patent numberU.S. 5196574). Commercial routesused to manufacture LAB are illustrat-ed in Figure 2.

Commercial LAB can vary interms of average molecular weight.DAT content, and phenyl isomer dis-tribution.

-0

Il

Table 1Solubility (cloud polntl') 01 LASas a function of average carbonchalnlength (15% of LAS with1% sodIum sulfate)

Cloud point("C)2.5

20.563.4

Cu-Avg. LASCtrAvg. LASCu-Avg. LAS

" Teml"'",.ure •• which IO'I> ~Iu';""$ 01" LAS .urn

ckludy (. \ovI'er cloud poin •• empenlun: ~ \(I.

hi&hn"..-.e« KJ!ubili.y)

Average molecular weightCommercial LAB is produced fromthe alkylation of benzene with variousblends of Cw• c., CI2, Cn. and CI4linear chloroparaffins or olefins. Dif-ferent average molecular weightLABs are available. normally averag-ing in the 232 (CII) to 260 (Cn)molecular weight range. This specificmolecular weight range provides bothacceptable solubility and surfaceactivity.

Increasing molecular weight above260 produces a LAS with better sur-face activity but very low water solu-bility. Decreasing molecular weightbelow 232 produces a very solubleLAS which has poor surface activity.The effect of LAB molecular weighton surface activity and water solubili-ty is shown in Figure 3 and Table I.

LAS molecular weight also has asignificant influence on LAS solutionviscosity, as shown in Figure 4. This iswhy high molecular weight LAS slur-ries usually have high viscosities, andare more difficult to handle in com-parison to low molecular weight LASslurries.

Optimal LAS molecular weight isdetermined by the conditions underwhich the LAS will be used. LASreacts with water hardness ions (calci-um and magnesium) to form insolublesalts. This interaction can effectivelyremove LAS from the wash liquor.lowering its concentration and effec-tiveness. Lower molecular weightLAS is much less sensitive to waterhardness than higher molecularweight LAS. and is therefore normal-ly used in formulations that do not

INFORM, Vol. 8, no. 1 (January 199n

Page 3: LAB Comp and LAS Performance

.-------------------------------------------------------------21

contain ingredients which controlwater hardness (builders). This is whyCII LAS is typically used in unbuiltlaundry liquids and dish washing liq-uids.

The effect of LAS molecularweight on detergency performance isillustrated in Figure 5. As shown. opti-mal detergency performance underlow water hardness (50 ppm) condi-tions is obtained with a higher molec-ular weight LAS. while a shorter car-bon chain length is best under highwater hardness conditions. Overallperformance decreases with increas-ing water hardness because waterhardness ions interact with soils andsolution components in addition 10LAS.

The effect of LAS molecularweight on foam stability (dishwashingperformance) is shown in Figure 6.Again. optimal performance isobtained with a high molecular weightLAS under low water hardness ccndi-nons. and with a low molecularweight LAS under high water hard-ness conditions. Note that. contrary towhat is observed in detergency. over-all foam performance increases withincreasing water hardness becausewater hardness ions help stabilizeLAS at the air-water interface (helpstrengthen the foam). This is whymanufacturers sometimes add mugne-sium salts to dishwashing liquid for-mulations.

Another factor related to molecularweight which can affect performanceis carbon chain distribution. Carbonchain distribution (the relative distri-bution of CI(). CII' C12• C13• and CI4homologs) affects LAS performanceproperties by determining averagemolecular weight. but it also canaffect performance if it changes therelative concentration of the lesserperforming (or better performing)homologs. For example. C\O LAS andCI4 LAS are good surfactants. but CI4LAS is not very soluble. and CIO LASis not very surface active. If the car-bon chain distribution were "peaked"so that average molecular weightremained the same but the ccncenca-tions of C\O LAS and Cl4 LAS weresignificantly reduced. then perter-mance would be enhanced because theconcentration of the better performing

'"75

s I--a1l~,70,'a

""il "~!!.",60! I-& I-g 55

~~SO

9

Permanem press

-,

- - ..- --..

_e-. 50 ppm water hardness-.... - 150 ppm water hardness--b- 300 ppm water hardness

1\ 14

homologs (CII• CU, and Cn) wouldbe increased.

In practice, varying the distributionof homologs requires more specializedparaffin feeds, which naturally wouldincrease manufacturing costs. Howev-er. variations do occur and should betaken into account when selecting anLAB.

In summary. LAB (or LAS) molec-ular weight is by far the most impor-

10

·l:I~

12 13 I'LAS carbon chaintength

75,-------------------,~"170

'a

j 65

!!.

160 t-

~ I-K. _ 50 ppm water hardness-g 55 -I50ppmwotcrhardnc:ss

Jt 5OL- L- L- ~L-_-I>-~JL_pp_m__ w_·_"1'_h._ro_.,.__ __l

9 10 II 12 13 14 15

~------..-------.-------~------~- _ ..- - - ... - - ..

Conoo

LAS carbon chainlcngth

Agure S. Detergency performance 01 LAS homologa, ea meaaured by Vllta LabMethod 303·91 (high 2·phenyl/hlgh OATS-type LAS at SO,150, and 300 ppm waterhardneaa; 16% LASI3O% sodium trtpo/ypholphate (STPP)llo% 11Iieateformutatlon; 0.15% concentratlon, l00"F, .. bumfduataoltl

..

tant factor to consider when formulat-ing with LAS. Other variations incomposition play significant but sec-ondary roles.

OAT levelAlkylation normally results in a singleattachment between the paraffin chainand a benzene molecule. Sometimes,however. attachment can occur twiceto form OAT or dialkylindane. The

tNfORM.Vol. 8. no. 1 (January 199n

Page 4: LAB Comp and LAS Performance

22

SURFACTANTS & DETERGENTS

,~" 2-Phenyl J2 18

" , 3-Phenyl 20"

,4-Pheny\ 17 20,, 5-Phenyl

"24,, 6-Phenyl " 18,, 7-Pheny\ I I,

b

13 14 "

-0-.0 ppm water hardness__ - 50 ppm water hardness-/:r- 150 ppm water hardness

Table 2Phenyl isomer distribution for "hIgh 2-phenyl" and "low 2-phenyl" ell aver-age LAB

Phenyl Isomer High 2·phenyl

distribution

Low 2-phen)"

distribution

zs

],20 • ,e / -,

~ /

0. /~ / ,,0 rs ,~ " .-E ,,00 .-0 ,• ,,~10 ,e .<>'• ~------

-e

s, 10 " 12

structure of these coproducts is shownin Figure 7.

Levels of OAT and dialkylindaneare detennined primarily by the alkyl-arion process itself. The chloroparaf-fin/Aiel] process produces alkylatethat contains 6-8% OAT, while theolefin/HF. olefin/AleI3• andolefin/solid alkylation catalyst pro-cesses produce alkylate generally hav-ing less than 1% OAT. Levels ofindane in all processes are low. gener-ally below the ability to measurethem.

OAT readily sulfonates to formOATS. A misconception is that OATSdoes not contribute to performance.OATS, however, is nearly as surface-active as LAS itself (Figure 8). Theonly difference between LAB andOAT is a second attachment betweenthe alkyl chain and the benzenemolecule. This second attachmentmakes the molecule more rigid. whichenhances its ability to affect solubilityand viscosity without significantlyreducing its surface activity.

OATS acts as a "structure breaker."which improves water solubility andlowers viscosity (Figures 9. 10). Thisis why chioroparaffin/AlCI3 LAS ispreferred for liquid formulations: it iseasier to formulate, and less expensivein terms of hydrotrope COSI. becauseof the presence of OATS.

Although OATS has a significamimpact on solubility and viscosity.its presence does nOI have a signifi-cant effect on performance becauseit is surface active (Figures 11 and12).

us carbon chainlcngth

Figure 6. Foam ltabillty (dllhwalhlng performance) of LAS homolog' (formulatIon ..24% LASi6% lauryl3-mole ether lutfalei'l% laury1 myristyl mono-elhanolamlde; at 0, 50,and 150 ppm walar hardnallj. Plales soiled with vegetable shortening; hand dlshwash-Ing lasl performed with 0.05% formulations USing Vista Lab Method 311·92.

oDialkyhndnnc(one of many possible isomers)

Dialkyhetralin(one of many possible isomers)

Figure 1. TWo possible coproduct structures

es

60

E ss~~ 50:s.~-e•~

40

,~as

30

zs-3 _2.5

... C12 LAS• COATS

_1.5

LogC (gIL)

-I -'1.5

Figure 8. Surface tension venus log (C) of C12 OATS and e12 LAS

INFORM. Vol. 8. no. 1 (Jonuary 1997)

Page 5: LAB Comp and LAS Performance

23

Table 3low 2-phenyl distribution of CII-and Cu' average LAB

Phenyl isomer CII" CU'everage a,-erage

2-Phenyl 18 I.3-Phenyl I. "4-Phenyl 20 "S-Phenyl 2' 226-Phenyl 18 237.Phenyl I "

Phenyl isomer distributionDuring the alkylation process, thebenzene molecule can end up attached10 any carbon along the alkyl chain(with the exception of the terminalmethyl groups), Two possible isomersare illustrated in Figure 13.

The "phenyl isomer distribution"refers to the relative concentration ofLAB molecules in which the benzenegroup is attached to the second carbonof the alkyl chain. the third carbon ofthe alkyl chain. the fourth carbon. andso forth. The phenyl isomer distribu-tion obtained during alkylation isdependent almost solely on the alkyla-tion catalyst. Alel3 and the propri-etary solid alkylation catalyst givewhat is normally called a "high 2·phenyl" distribution, while HF gives a"low 2-phenyl" distribution, The "2-phenyl" designation is used simply todistinguish between the two majortypes of alkylute (Table 2).

Phenyl isomer distribution isaffected by carbon chain distributionor average molecular weight. A highermolecular weight means that the aver-age chain length of the alkyl chain islonger, which means that more iso-mers are available. For example, a CII

LAB molecule has five possible iso-mers (2-phenyl, 3-phenyl, a-phenyl, 5-phenyl, and 6-phenyl), while a CoLAB molecule has six possible iso-mers (2-phenyl. j-phenyl. a-phenyl. 5-phenyl. e-phenyt. and 't-pbenyl).Increasing the molecular weight there-fore results in a broader distributionsince more isomers are possible. Thisis illustrated in Table 3.

5Or;:=:::::::;::=-=:::::;---~_A-. High 2·phcnyllhigh

DATSCI1 LAS...... _ High 2·phenyl/low

OATS CI1 LAS....... Low 2·phcnylllow

OATS CI1 LAS

~~~.~

----- -

._10 L_---' __ ---'__ ---'-__ --'--__ --'--_---l10 " 20

LAS concentration ('lo..,-..,...--. wIodIlOto_"'LAS ......-,. (a_-pc.-......,.....,_ ...........- ........,.)

Figure 9. LASaolubillty«:Ioud point) II. function of (:onc:enlnltion(2% salt Iddecf)

7~h===~;=~==~----------~_A-. High 2.phenyllhigh

OATS CI1 LAS......_ High 2-phenyl/low

DATSCII LAS

....... Low 2·phcnyl/lowDATSC11 LAS

6000 i

//

3000 -

~L,-------W~------~3L,-------l~c-------.L,C------150LAS coocentllnion ('lo)

Figure 10. VlSCOltty venul percenllge LAS(30"C. shear rate", 10 sec-1)

Under practical use concentrations.when LAS is dissolved in water, mostof the LAS aggregates into micelles.and the remainder stays in solution asindividual molecules called

Phenyl isomer distribution has littleeffect on performance (Figures I I,12) except with respect to water solu-bility and formulatability in liquidproducts.

INFORM. VOl. 6. no. 1 (Jonuory 1997)

Page 6: LAB Comp and LAS Performance

24

J

SURFACTANTS & DETERGENTS

Table 4CompoSition 0' commercial LAB

Property AICIJ-calalyzed HF-catalyzed Solid-calalyxedalkylation alkylation alkylation

Average carbonchain C11-C1) CII-C13 CI:,-CJ3

Percentage 2-phenyJ 27-30 15-24 21-30

Percentagedialkyllctrni inlindane 6-10" <I <I

Q<I\1, irolcfi"' .... uJQi;~ad 01ch~1IJ.

LAS carbon chainlength

Flgur. II. Detergency performance 01 LAS homolog., .1 measured by Vllta Lab Method303-91 [high 2-phenyllhlgh OATS-type LAS VI. low 2'phanyll1ow OATS-type LAS II ISO ppmwlt.r hardn ... ; 16% LASI3O% STPPflO% eiueete formulation; 0.15% concentration, lOO"F,.. bum/dult 80U)

as

i; 20

~•-a~0

"~E•0•~10e•-e ,,

-,... High 2-phenyl/highDATS LAS

10 " 12 IJ 14 "LAS carbon chainlcnslh

Rgur.,2. Foam Itllbility (dlahw •• hlng perlor~nc:.lof LAS I'Iomologl, a. measured byVista LIb Method 311-92.. (formulation" 24% LASJ6'l1oLauryl3-mo1e ether lulf.tel2% 'aurylmyrIlty1 mono-elnanolamlne; high 2-phenyllhigh DATs-type LAS, and low 2-phenylllowDATS-type LAS)

, 6 4 2

4 6 s J

2-Phenyt isomer

J s 6 4 2

5·Phenyl isomer

Figure 13. Two po .. lble phenyl isomers

monomers. As the solution is cooled.the monomers precipitate individuallyas their solubility limit is reached. Thetemperature at which each monomerprecipitates depends on its inherentsolubility and concentration. Themonomer concentration. in turn.depends on the composition of themicelle. It is possible to calculate thecomposition of the micelle and fromthis. the concentration of eachmonomer.

From each monomer concentrationand its inherent solubility. it is possi-ble to predict the temperature at whichthe solubility will be exceeded. Exper-imentally. it is found that a high 2-phcnyl LAS distribution has a highersolubility than a low 2-phenyl LASdistribution. This is why high 2-phenyl LAS is preferred for liquid for-mulations.

The bottom lineIt is important to understand howLAB composition can vary. and howthese variations can affect perfor-mance. The composition of commer-cial alkylates is given in Table 4.

The impact of compositional vari-ables is somewhat dependent on theapplication. In general, molecularweight is the major factor since it con-trols both surface activity and solubili-ty. A high OATS content and/or a high2-phenyl isomer distribution makes iteasier and less costly to formulate aliquid product. •

INFORM. VOl. 8. no. 1 (Jonuory 1997)

Page 7: LAB Comp and LAS Performance

28

SURFACTANTS 8. DETERGENTS

Current environmental issues for surfactantsThe most complete and desirable pro-cess for determining the environmen-tal acceptability of commercially usedsurfactants is commonly referred to asrisk assessment. In this process. fieldmonitoring studies are done to deter-mine concentrations of a surfactant inenvironmental compartments of inter-est. such as wastewater treatmentplant effluents, surface waters, sedi-ments. or soils. It also is possible toestimme environmental concentrationsby applying models which predict thefate of chemicals in the environment.The measured or predicted field con-centrations then are compared withthe concentrations of the surfactantknown to be toxic to organisms Jivingin the affected environmental com-partrncnrs. If the measured concentra-tions are less than the toxic levels, amargin of safety exists, and the surfac-tant is considered to be environmen-tally acceptable at current use levels.

Even though this approach is themost desirable process for determin-ing the environmental acceptability ofsurfucumts. it is expensive in terms oftime, manpower. and money. At times,evaluations have been made withoututilizing the whole risk assessmentprocess, thus resulting in misconcep-tions and erroneous conclusions thatpersist in the marketplace. These are:(a) claims that oleochemical-basedsurfactants are environmentallypreferable to petrochemical-based sur-Iactants: (b) claims thai surfactantswhich don't manifest anaerobicbiodegradation in certain tests wil1accumulate and harm the environ-ment: and (c) undue reliance on labo-ratory biodegradation screening testresults for estimating the environmen-tal fute of surfactants.

Environmental acceptability of sur-IactantsOver the last several years. claimshave been made that oleochemical-based surfactants are environmentallypreferable to petrochemical-based sur-factnnts. For example, papers makingsuch claims were given at the 3rdCESIO International SurfactantsCongress in London, United King-

TIre fol/owing article was written by AII~n M. Ni~/srnof Condra Visfa Co., 12024 Vista PaTh! Dr.. AlISlin,TX 78726.

dom. in 1992. and at the 3rd WorldConference on Detergents in Mon-treux. Switzerland. in 1993 (1-3).

These claims are based, in part,upon results from laboratory biodegra-darien test results in which differencesin biodegradation rates have beenobserved. Because of the significantbusiness and political implications ofsuch claims. two major studies toevaluate these claims were undertakenby the European surfactant industry(4.5) and the Dutch government (6).

The first approach taken was toexamine the environmental impact ofproducing surfactants by doing a LifeCycle Inventory (LCI). An Lei con-sists of determining the amount ofenergy and raw materials consumed 10produce a surfactant and its feedstocksas well as quantitating the amounts ofatmospheric, waterborne, and solidwaste emissions intrinsic to these pro-cesses. This study was very thoroughin that all of the commercially impor-tant oleochemical- or petrochemical-based surfuctunts were analyzed (4.5).A summary of this massive study isshown in Table I. which depicts anoverview of the total resource require-ments and environmental releasesinvolved only in production of thesesurfactants (data are from Tables 2, 3,and 4 of Reference 5). An evaluationof the requirements and releasesoccurring during torrnutauon intodetergent products was not included inthis study. The surfactanrs are listed inthe left-hand margin. with a notationof whether they are derived frompetrochemicals (Pc). oleochemicals(Oc). or a combination of both. The

information presented includesrequirements for raw materials. con-sumption of energy. and atmospheric.waterborne. and solid waste releases.All data are normalized to the produc-tion of 1000 kilograms of the surfnc-rant.

These results show no clear differ-ences in the overall amounts of energyand raw materials consumed or emis-sions produced between the oleo-chemical- or petrochemical-based sur-factants. Since there is no agreementwithin the scientific community as tohow to rate the environmental impactof the emissions and consumptions, noimpact assessment was done. Howev-er, the overall conclusion from thestudy is that the potential impact fromproducing either oleochcmical- orpetrochemical-based surfactantsappears to be about the same. Thisconclusion is clearly stated in theabstract of the summary paper for thisstudy (5): "Based on the findings. nounequivocal technical rationale existsfor claiming overall environmentalsuperiority. neither for production ofindividual surfactants nor for the vari-ous options for sourcing from petro-chemical and oleochemicaVagricultur-al feedstocks and minerals. The valueof the study lies in allowing each man-ufacturer to assess opportunities forimproving the environmental profileof its surfactants and intermediates."

The second approach, mandatedby the Dutch government (6) andsupported by the surfactant industry.particularly the Dutch Soap Associa-tion (NVZ). consisted of an exhaus-tive risk assessment for the four

INFORM. Vol. 8. no. 1 (January 1997)

Page 8: LAB Comp and LAS Performance

29

Table 1Overview of total resource requirements and environmental releases

Surfactant" Requirements geteeses

Raw materials Energy Atmospheric Waterborne Solid waste(kg/JOoo kg) consumption (kgllOOO kg) (kg/JOoo kg) (kg/lOoo kg)

(GJflOOO kg)

LAS p, 1040 61 1661 5 65

AS Pc 1091 73 2604 7 81oe 2077 57 1684 26 75

AE, p, 1310 73 2335 5 68oe 2167 67 2024 2. 96

Sao. oe 2167 50 4451 .5 144SAS Pc 1013 52 1261 2 64

AE, Pc 1448 83 2366 6 67oe, Pc 2401 73 2044 28 66

AE, Pc 1570 7. 2281 6 64Oc,Pe 2264 72 2062 21 64

AEII Oc,Pe 2064 82 2299 11 63APG oe 2060 63 2015 35 142

a Pc. pelnxhrmical; Oc *oleochcmi<:al; 0.:, Pc = derived from borh p"tro- and olt:ochcnlicak

major surfuctnnts used in The Nether- o«. 30, 1995, Minister of Public MTR values for the four ingredientslands: linear alkylbenzcnc sulfonate Housing, Physical Planning. and (listed in Table 2) turn out 10 be in the(LAS). alcohol cthoxylates (AE), Environmental Management (VROM) same order of magnitude for LAS.alcohol ether sulfates (AES), and Margaretha de Boer wrote: "A very AE, and AES. The MTR of soupsoap. This study. which took over extensive inventory was made by the appears to be clearly lower. This canfive years to complete, consisted of detergent industry of the available be explained by the absence of chron-four phases: (a) collection and evalu- ecoroxicologtcat data of these four ic toxicological data for this sub-arion of published and unpublished ingredients. These data were subsc- stance. However, the tentnnvc resultsdata from laboratory and field tests quently evaluated by RIVM (National of a chronic study with soap indicatefor environmental fate and effects of Institute of Public Health and Envi- that the toxicity of soap is comparablethese surfactants, (b) estimation of ronmental Protection), after which, in to that of LAS, AE, and AES. Thisenvironrnentul concentrations by the consultation with industry. the Maxi- means that the MTR of soap is pre-use of accepted modeling techniques, mum Tolerable Risk level (MTR) for sumably higher than listed in the(c) actual field monitoring of LAS, surface waters was determined. The table.AE, AES, and soap in wastewatertreatment plant effluents and down-stream receiving waters in The Table 2Netherlands, and (d) calculation of Maximum tolerable risk (MTR) level and negligIble risk levels (VR) for surfacesafety margins between surfactant waters of four detergent Ingredientslevels in the environment and theireffects on the organisms living there. Ingredjente MTK (]Jg/L)b VR (]Jg/L)bDutch government officials conclud- LAS 250 2.5ed that these four surfactants (based AE 110 1.1on oleochemicals and on petrochemi- AES 400 4.0cals) were acceptable at current use Sao, 27 2.7levels. and further analysis was notrequired. " Valucs .., forCu ~s. CuEOu "E, (),,,EOu AES.

In the official letter to the chair- b VaIuo:s fordi ...",h-..1 .......... in .....race"'"Mer$.man of the Dutch Parliament dated

INfORM. Vol. 8. no. 1 (Jonuory 1997)

Page 9: LAB Comp and LAS Performance

30

SURFACTANTS & DETERGENTS

Table 3Removal of LAS from a German (Edewechterdamnl sludge-only landfill

Age (years) LAS concentration(mglkg)

9160861031701560245

Deposition period

19861983-19851979-19831975-19791972-1975

0.51-33-7

7-1111-14

rent use levels.The above studies demonstrate the

value of utilizing all the 1001s avail-able instead of relying solely on labo-ratory biodegradation tests to arrive atimponant conclusions concerning theenvironmental acceptability of surfac-rants.

"For the research to the actualexposure in the aquatic environment.in a cooperation between NVZ. RLZA(National Institute of Surface Waterand Wastewater Management).RIVM, and the University of Amster-dam. a monitoring study was per-formed on the concentrations of thefour ingredients in influents and efflu-ents of seven sewage treatment plants.Subsequently, modeling was used tomake an estimate of the concentra-tions of the substances in surfacewaters. From this monitoring study, itbecomes clear that the removal of thesubstances in sewage treatment plantsis almost complete (99.1-99.8%). Asa consequence, the expected concen-trations in the surface waters (PEC)close to the plants are low, about afactor of 100 below MTR level.Therefore, it can be concluded fromthis risk assessment that the environ-mental risks for the use of these sub-stances in (luundry and cleaning)L&C products are acceptable by dis-posal to normal-functioning sewagetreatment plants. Assuming that thisis the case in The Netherlands, Iappraise the usage of these substancesas acceptable in every respect."

All of the ecotoxlcologtcat datawere normalized to LAS: C11.6: AE:C\J.3 EO:S.2 AE5: Ct2.S E03.4 sincethese are representative of the com-mercial surfactants present in theaquatic environment in The Nether-lands (6).

Other evaluations done by theEuropean Union for laundry detergentecolabel (7) and the British govern-ment (8) confirm the general conclu-sion thai currently used surfactarusincluding those derived either frompetrochemicals or oleochermcals arenot a threat to the environment at cur-

Significance of 'anaerobic'biodegradabilityThere has been concern that surfac-tants will accumulate and persist ifbiodegradation is limited in anaerobicenvironments. This concern has result-ed in requirements for anaerobicbiodegradability in certain ecolabelprograms in Europe and Scandinavia(7,9). These are the result of anincomplete evaluation of existing dataas well as the fact that no overall riskassessment evaluation has been donefor chemicals in anaerobic environ-ments.

Strictly anaerobic environments aremuch less prevalent in nature than aer-obic or microaerophilic environments,and they typically house a minor por-tion of the total volume of surfacmmsreleased to the environment. Anaero-bic habitats also playa transitory rolein the biodegradation of surfactantssince these reach the environment ascomponents of domestic and munici-pal wastewater and are extensivelyexposed to aerobic conditions before.during, and after wastewater treatment(10).

The anaerobic biodegradation testmethod most commonly required inthe ecolabel programs is found in theEuropean Chemical Industry Ecologyand Toxicology Centre's(ECETOC's) Technical Report No.28 (11). This method consists ofplacing the surfactant in a sealed bot-

tie with a nutrient medium andsewage sludge and then measuringthe gaseous products of anaerobicbiodegradation with time. Thismethod only simulates the environ-ment found in anaerobic digestorsused in wastewater treatment plantsin which sludge from the process isexposed to anaerobic digestion in aclosed tank. The ECETOC methoddoes not simulate what is happeningin other so-called anaerobic environ-ments such as landfills. sediments,and flooded soils. In these actualenvironmental compartments. expo-sure to oxygen occurs often by vari-ous mechanisms such as diffusion ofgaseous oxygen. exposure to waterwith dissolved oxygen. physical dis-ruption by air or water movements,and action of the biological popula-lion. More evidence that exposure tooxygen is occurring in these compart-ments is that aerobic and facultativeanaerobic as well as strictly anaero-bic bacteria can be cultured fromthese environments (12).

The fate of LAS in so-called anaer-obic environments illustrates the erro-neous conclusions which can beformed if one only considers theresults from laboratory anaerobicbiodegradation tests such as the ECE-TOC No. 28 test method. The initialstep in biodegradation of LASrequires oxygen (13) so LAS fails theECETOC No. 28 lest; however, thereare examples which demonstrate thatLAS is nOI accumulating in "anaero-bic" environments such as sedimentsor landfills.

Table 3 is a summary of LAS anal-ysis done in a German sludge-onlylandfill. This landfill is from 8-10meters deep and has been in operationsince 1972. It receives digested sludgefrom the Edewechterdamm wastewa-ter treatment plant, which treatswastewater from the city of Bremen.The samples were taken in PVC lin-ers. dried. pulverized, extracted, andanalyzed. Samples were taken at dif-ferent depths in order to analyzesludges of different ages. as noted inTable 3. It was possible to calculatethe approximate ages of the sludgesamples by evaluating the sludge

INFORM,VOl.8, no. 1{January t99n

(t;onlinu~donpog~32)

Page 10: LAB Comp and LAS Performance

32

SURFACTANTS & DETERGENTS

.1

Ij

--6- Me.. un:d ""ter (IIIVL)

..... COk:uJ ...... lledi nl (111"1)

~ Meuured Kdi nl (jI.fl)

Sampling location in ,,,....{tm)

FIgure 1. Calculated and measured dlsappearal'lC8 of linear alkylbenzane sulfonate (LAS)In river water and aedlmenla

(continued/rom page 30)

deposition records of the wastewatertreatment plant. Over a 14-year peri-od, the concentration of LAS in thesludge decreased by >97% (14).

Another striking example of thebiodegradation of LAS in a so-calledanaerobic environment is shown inFigure I. taken from the work of lar-son and colleagues (15). This studywas carried out downstream of theRapid City, South Dakota. USA,wastewater treatment plant which dis-charges into Rapid Creek. RapidCreek is a mountain stream whoseflow is regulated by the Pacrola Damsome 32 kilometers upstream ofRapid City. It flows 100 kilometersdownstream from Rapid City to theCheyenne River. The only discharge

into Rapid Creek comes from theRapid City wastewater treatmentplant, a trickling filter plant. Monitor-ing sites were at 0.8, 12, 25. and 48kilometers downstream of the plant.During the fall sampling period, grabwater samples were collected frommidchannel and sediment samplesfrom nearshore locations. The datareported here came from a samplingexercise in which the samples werecollected in a time sequence based onflow velocity. so that a single volumeelement of water could be followeddownstream. The samples wereimmediately frozen. shipped to thelaboratory, extracted, and analyzed.The major point of this figure is thatthere is a large difference when acomparison is made between the con-centrations of LAS measured in the

8r.odfORi So.>.p W""'''. Lid.Chn,cr. 011 4QL. En8bnd024+'-M'lIOO

BRADFORDOri(!inal Rr;odford So..p Wor .... Inc.......,.., .....a,...;ck. RI 0".!89~USA(<fOI) 821-2141

For inlormation circle' 134

sediment versus those calculated to bein the sediment if no biodegradationwere to occur. Notice the large differ-ence at the 12- and 25-kilometer sam-pling points .

Takada and coworkers (16) studiedthe fate of LAS in sediments of theTokyo Bay system. They measured theconcentrations of LAS in the riversfeeding the bay, the upper and lowerestuaries, and the bay itself. Theyfound that >99.99% of the LAS dis-charged to the rivers was removed bythe time it was transported to the bay.

The final example is a worst casesituation. In northern Wisconsin,USA, near a small town called Sum-mit Lake is a laundromat operation.The discharge from the laundromatgoes into a natural depression whichhas resulted in the fonnation of a per-manent pond and wetland ecosystemshown in Figure 2. Although the pondsystem has been exposed to high con-centrations of detergent chemicals formore than 25 years, significant con-centrations of LAS have not beendetected in any of several monitoringwells drilled in the area. Work wasdone to show that soil collectedbeneath the laundromat pond still hadLAS biodegradation capabilities eventhough it was assumed that the soilwould have been anaerobic.

The removal of LAS with soildepth beneath the laundromat pond isshown in Figure 3 as LAS decreasedfrom >200 ~g/g to <2 Ilg/g over a ver-tical distance of less than 3 meters(17). The samples were collected bydrilling to various depths, and coreswere removed with specialized sam-pling apparatus to avoid cross contam-ination. The samples were frozen,shipped to the laboratory, extracted.and analyzed for LAS.

These four examples demonstratethat a surfactant such as LAS thatwould fail the ECETOC No. 28 test isbeing biodegraded and removed in so-called anaerobic environments such assediment. landfills, and deep soils.Therefore, this test method does notsimulate many of the anaerobic envi-ronments of the world.

Laboratory work by Larry Brittonand colleagues (18.19) provides anexplanation why LAS degrades inthese apparently anaerobic environ-

INFORM. \-tlI. 8. no. 1 (January 199n

Page 11: LAB Comp and LAS Performance

33

Monitoring well

./ u!

Laundromat24 wasters

Algal-bacterial mat

./Laundromat pond

Clay Organic flocClay

Sandy vadose zone

,,~,

Groundwater \.IIble--H---------------~--------------~~~~Groundwater flow

~~---;.....Agure 2. Sen-matlc dlagrlm showlng the maJOI'"environmental eonlpertmentl 01 the Summit lake Laundromat pond system

ments. In the test (test set-up shownin Figure 4), 75 mL sediment slurrywas placed in a vessel with small-bore Teflon tubing distributedthrough it. The lest vessels were 150-mL glass serum bottles with greybutyl rubber septa. The amount ofaeration going to the sediment wasregulated by controlling the flow rateof oxygen through the tubing. Oxy-gen was introduced into the test ves-sels by diffusion through Teflon-typepolytetrafluroethylene (PTFE) tubingof various lengths. Each flask was fil-led with a 2-mL high-densitypolyethylene centrifuge tube contain-ing I.5 mL of 0.25 M KOH to trapany CO2 produced by the sedimentmicroorganisms. {l4C] - benzenering-labeled CI2 LAS was added at 5ppm (I x 106 dpm). In this experi-ment. the flow rate of oxygen wasreduced to the point that the rate ofoxygen consumption by the sedimentwas greater than the rate of oxygencoming into the system or. in otherwords. the environment would be

called anaerobic even though oxygenwas still coming into it. Even in thisapparent anaerobic environment.LAS underwent complete biodegra-dation and mineralization (conversioninto CO2), The results are illustratedin Figure 5.

Furthermore, additional studies bySalanitro and Diaz (20) have demon-strated that the concentrations of sur-factants required by the ECETOC No.28 test method are toxic to sludge anddo nor reflect the levels actually foundin anaerobic digester sludge.

Based on the pattern of use. themajor environmental compartmentsexposed to surfactants are primarilyaerobic. Chronic exposure to anaero-bic conditions is limited and not like-ly to significantly impact environ-mental concentrations. To illustratethe importance of aerobic biodegra-dation in controlling the environmen-tal fate of surfactants, a mass balancefor LAS can be constructed for theUnited States. In the United States.75% of LAS is treated in municipal

wastewater treatment systems andabout 25% in on-site treatment sys-tems such as septic tank systems. Ofthe fraction going 10 municipal treat-ment systems. -77% is removed bymineralization and 22% is sorbed tosludge which is disposed of via incin-eration. addition to soils. or landfills.LAS associated with sludge contin-ues to undergo extensive aerobicbiodegradation in surface soils and,as discussed earlier, will undergoslow but significant biodegradation inlandfills. Of the fraction going 10septic tanks, only 5% is mineralized.22% is sorbed to sludge, and theremaining 73% is discharged to sub-surface soils where extensive aerobicbiodegradation has been confirmed.The septic tank sludge is disposed ofin municipal treatment systems orapplied to soils where continued aer-obic biodegradation occurs. The netresult is that over 99% of the LASadded 10 the environment has beenremoved by aerobic mechanisms( 10).

INFORM. Vol. 8. no. 1 (JonUOf)' 1997)

Page 12: LAB Comp and LAS Performance

34

SURFACTANTS & DETERGENTS

test compounds during the tests. Thesetradeoffs can lead to potential falsepositive or negative results.

For example, surfactant concentra-tions in most standard biodegradationleSIS range from JO to 100 mgIL sothat simple analytical procedures forthe surfactants can be utilized. Unfor-tunately, these concentrations may betoxic to the natural bacterial popula-tions used in the tests. Many times Ihisis due 10 the fact thai the environmen-tal concentration of the surfactant maybe orders of magnitude lower that thetest concentrations. Larson and hiscolleague (21,22) demonstrated thiseffect with LAS in river die-away testsutilizing Ohio River water in whichthe natural concentration of LAS wasmeasured to be 50 ~gILbut tests weredone at 5, 10, 20, 40, and 80 mglL.Not surprisingly. no activity was notedat 20. 40. and 80 mgIL because of tox-icity. Biodegradation occurred at 5and JO mgIL but only after lag limesof al least four days. Only when therests were done at 50 Ilg/L didbiodegradation begin immediately(21.22).

A second critical issue is the use of"acclimated" and "nonacclirnated'microorganisms in the tests. Asdescribed above. if microorganismsare exposed to certain levels of a sur-factant in the environment but testedat much higher concentrations in thetest method without being acclimatedto the higher concentration, negativeresults will likely be observed even ifit is biodegradable at environmentalconcentrations. However, many timesthe microorganisms can "acclimate"to the higher test concentrations anddemonstrate adequate biodegradationeven at the unrealistically high testconcentrations. An important exampleof this is encountered in doing the pre-sumptive test for LAS in the ASTMTest Method 0-2667-89. "StandardTest Method for Biodegradability ofAlkylbenzene Sulfonate" (23). Thismethod states that the test must bedone at 30 mglL. It has been docu-mented (24) that only in very concen-trated row sewage could 30 mgIL LASbe encountered in the environment. Itis very clear that when this method

[continued on pag~36)

'"o

Agure a. Decrease In LAS concentrations as a lunction 01 depth In soli samples collectedbeneath the laundromat pond system

+--0, +--0,Initial JlWlCof~I with N2to create anxrobic conditiom

4111 NIUTOWbon:. ihin·,,-all PTFE tubing

4111 Stir bar

150 mL seplum sealed serum bottle

Figure 4. Oxygen diffusion lest vessel

The risk assessment approachteaches us several facts about surfac-tarns. such as LAS, which may notpass a laboratory anaerobic test: (a)aerobic conditions dominate in theenvironment, and aerobic biodegra-dation accounts for >99% removalof LAS; (b) many environmentswhich were assumed to be anaerobicactually do have oxygen penetratingthem which allows for aerobicmetabolism to continue: and (c) thetrace quantities of LAS which maybe found in strict anaerobic environ-ments such as deep and undisturbed

Undue reliance on screeningbiodegradation testsTo understand the significance ofresults from laboratory biodegradationtests. it is important to remember thaievery biodegradation test is a series oftradeoffs between an attempt to simu-late some environmental compartment(such as a surface water) and the prac-tical concerns of setting up the testand analyzing the disappearance of

sediments are well below those lev-els having adverse ecotoxicotogicnlimpacts.

INFORM. Vol. 8. no. I {January 199n

Page 13: LAB Comp and LAS Performance

36

SURFACTANTS Be DETERGENTS20.000

18.000 f-

~ 6,000

0,000

~'000 -"""'"00 20 <0 60 OJ "'0 '20 ,<0 '60

16.000

~ 14,000

-; 12.000

110.000

e 8.000

Time(houn)

Agure 5. Minefllilution 01LAS under Manaeroblc~conditions (oxygen cGnlumptlongrealer than oxygen diffusion)

(continued from IKlge 34)was developed in the 1960s, this con-centration was selected because ofanalytical considerations, and this isnot an environmentally realistic con-

centration. Also, recent experience hasdemonstrated thai negative resultsusually occur with this test if this con-centration is used. However. someyears ago it was demonstrated that

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INFORM. Vol. 8. no. 1 (January 1997)

with enough time. activated sludgecultures could be acclimated to 30mg/L LAS so that positive resultswould be obtained (Allen M. Nielsen,Condea Vista Company, unpublishedreport).

To correct this problem, theASTM subcommittee E47.06 hasrevised Method D-2667 and changedthe concentration from 30 mgfL to10 mg/L. Data developed by the sub-committee confirmed that thischange would alleviate the problemso that reliable positive results couldalways be obtained with the refer-ence materials. The revised methodis in publication.

The best approach to doing labora-tory biodegradation tests is a tieredapproach as recommended by theDECD Expert Group on Degradationand Accumulation (25). The objectiveof this approach is to provide a systemwhich allows for preliminary screen-ing of chemicals, using relatively sim-ple tests. in order to identify thosechemicals for which more detailedand more costly studies are needed.The screening tests are then followedby more definitive but consequentlymore complex and costly tests. Thethree tiers are: ready biodegradability,inherent biodegradability, and simula-tion tests.

The ready biodegradability testsare designed to provide limited oppor-tunity for biodegradation in water-based media using "nonacclimated"microbial populations. If a positiveresult is obtained, it can be assumedthat the test chemical will rapidlybiodegrade in the environment. How-ever, as stated by the Expert Group,"A negative result does not necessarilymean that the chemical will not bebiodegraded under relevant environ-mental conditions, but that it will benecessary to progress to the next levelof testing."

The inherent biodegradability testsare designed to assess whether thechemical has any potential forbiodegradation. These tests allow forprolonged exposure of the test com-pounds to microorganisms, higherconcentrations and diversities ofmicroorganisms, rich media, andother conditions which may favorbiodegradation. Positive results indi-

Page 14: LAB Comp and LAS Performance

cate that the chemical will not persistin the environment. In those caseswhere a more accurate estimate ofenvironmental concentration isrequired to ensure that undue risk tothe environment does not occur. itmay be necessary to proceed to thenext level and do simulation tests. Anegative result will normally meanthat further work on biodegradabilityis not necessary and that persistencemay be assumed.

Simulation tests are designed toprovide evidence of the rate ofbiodegradation under some environ-mentally relevant conditions. Thesetests are more expensive because theyusually entail extensive research andmay require \t4CJ_ radiolabeled testcompounds.

Furthermore, even if the very bestsimulation possible is used. as a gen-eral rule the results from laboratorytests underestimate what happens innature (15.26).

In summary. screening biodegra-dation tests underestimate thebiodegradation potential of manycompounds including surfactantsbecause of the use of unacclimatedmicrobial populations and unrealisti-cally high test concentrations. Fur-thermore. even if the best simula-tions of the environmental compart-ment of interest are done. these labo-ratory tests will almost alwaysunderestimate the biodegradationcapabilities of the real world. There-fore. the use of screening levelbiodegradation tests to make deci-sions concerning the environmentalfate of a surfactant will likely begrossly overconservanve and elimi-nate useful surfacrants from the mar-ketplace.

Finally. it is evident that the rigidapproach to decision-making basedonly on laboratory test results is notthe best. The best approach is to mea-sure or estimate the levels of a surfac-tant in the environment and comparethat 10 the levels at which it causeseffects on biological occupants of theenvironmental compartment in ques-tion.

AcknowledgmentsThis paper was presented at the 1stSeminar and Exposition on Surfac-

tams. HOUSEHOLD '96. Brazil.Sao Paulo, Brazil, held June 24-25.1996.

ReferencesI. Yamane. L Detergent Raw Mate-

rials and Ecologies in Japan, Pro-ceedings of the 3rd CESIO Inter-national Surfoctoms Congress &Exhibitioll-A World Market, Ple-nary Lectures. A & B. London.United Kingdom. June 1-5. 1992.pp. 15-38.

2. Hovetmann. P.. The Basis ofDetergents: Basic Oleochemicals.Proceedings of the 3rd WorldConference on Detergents: Glob-al Perspectives. edited by ArnoCahn. AOCS Press. Champaign.IL, 1994. pp. 117-122.

3. Satsuke. T.. Methyl Ester Sul-fcnares: A Surfactant Based onNatural Fats, Ibid .. pp. 135-140.

4. Tenside Surfactant Detergents32(2).-82-193 (1995).

5. Stalmans M.• H. Berenbold. J.L.Bema, L. Cavalli. A. Dillarstone.M. Franke. F. Hirsinger. D.Janzen. K. Kosswig. D. Postleth-waite. T. Reppert. C. Renta. D.Scharer. K.-P. Schick. W. Schul.H. Thomas. and R. Van Sioten,European Life-Cycle Inventoryfor Detergent Surfactant Produc-tion. Ibid.:84-109 (1995).

6. Feijtel, T.C.J .. and E.1. van dePlassche. Environmental RiskCharacterization of 4 Major Sur-foctonts Used in TIle Netherlands,Report 679101-025. NationalInstitute of Public Health andEnvironmental Protection andDutch Soap Association. Septem-ber 1995.

7. The Commission of the EuropeanCommunities. Commission Deci-sion of 25 July 1995. Establishingthe Ecological Criteria for theAward of the Community Ecolabelto Laundry Detergents. Officialloumal of the European Comma-nates. Sept. 13. 1995, pp. 14-30.

8. United Kingdom Department ofthe Environment. 2nd Report ofthe Technical Comminee onDetergents and the En"ironmellf.1994, pp. 53-60.

9. Nordic Environmental Labeling,Environmental Labeling of Deter-

37

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DynamicPropertiesof InterfacesandAssociationStructuresV. Pillai and D.O. Shah, editors

In recent years. dynamic structuresof amphiphites have generatedtremendous research activities dueto their wide ranging technologicalapplications. Therefore, this mono-graph should be of great interest toresearchers both in academia andindustry. The book also includes areview on "Dynamics of organizedassemblies of amphiphiles in solu-lion" by Dr. R. Zana. It containscurrent stare-of-the-an informationon fundamental aspects. properties.technological applications. andmethods to study dynamics of inter-faces and assoctenon structures. aswell as valuable references on allthese topics.

This monograph should be "crylise/ill (0 novices as well as expertsworking on dynamic properties ofintufaces Qild association struc-'"res im'ol"jng surfactants a"damphiphilic polymers.

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SURFACTANTS & DETERGENTS

gents for Textiles. Detergents0613.1. Feb. 2. 1996.

10. Birch. R.R., W.E. Gledhill, R.J.Larson, and A.M. Nielsen. Roleof Anaerobic Biodegradability inthe Environmental Acceptabilityof Detergent Materials. Proceed-ings of the 3rd CESIO Interna-tional Surfoaants Congress &£r:hibitiOll-A \Vorld Markel. Ses-sions £. F & LCA Seminar, Lon-don, United Kingdom, June 1-5,1992, pp. 26-33.

II. European Chemical IndustryEcology and Toxicology Centre(ECETOC), Evaluation ofAnaerobic Biodegradation, Tech-nical Report No. 28. Brussels,June 1988.

12. Pfennig, N., Formation of Oxy-gen and Microbial ProcessesEstablishing and MaintainingAnaerobic Environments, In

Strategies of Microbial Life illExtreme Environments. edited byM. Shilo. Dahlem Konferenzen,Berlin, 1979, pp. 137-148.

13. Schobert. P., Basic Principles ofLAS Biodegradation. TensideSurfactant Detergents 26(2):86-94 (1988).

14. Marcomini. A .• F. Cecchi, and A.Sfrisco, Analytical Extraction andEnvironmental Removal of Alkyl-benzene Sulphonates. Nonylphe-nol and NonylphenolMonoerhoxytate from DatedSludge-Only Landfills. Environ.Tech. 12:1047-1054(1991).

15. Larson. R.J .. T.M. Rothgeb. R.J.Shimp, T.E. Ward. and R.M. Ven-tullo. Kinetics and Practical Sig-nificance of Biodegradation ofLinear Alkylbenzene Sulfonate inthe Environment. J. Am. OilChem. Soc. 70:645-657 (1993).

16. Takada. H., R. Ishiwatari, andN. Ogura. Distribution of lin-ear Alkylbenzenes (LABs) andLinear Alkylbenzene Sul-phonates (LAS) in Tokyo BaySediments. Estuarine. Coastaland Shelf Science 35:141-156(1992).

17. Larson. R.J .. T.W. Federle. R.J.Shimp. and R.M. Ventullo.Behavior of Linear AlkylbenzeneSulfonate (LAS) in Soil Infiltra-

uon and Groundwater. TensideSurfactant Detergents 26(2),116-121(1989).

18. Britton. L.N .. and A. M. Nielsen.Relevance of AnaerobicBiodegradability Testing to Envi-ronmental Fate. Abstract I02P.First SETAC World Congress,Ecotosicology and Environmen-tal Chemistry-A Global Per-spective. Lisbon. Portugal. March28-31. 1993.

19. Heinze. J.. and L.N. Britton.Anaerobic Biodegradation: Envi-ronmental Relevance, Proceed-ings of the 3nl World Conferenceon Detergents: Global PerSIJeC-rives, edited by Arno Cahn.AOCS Press. Champaign, IL.1994. pp. 235-239.

20. Satanuro. J.P .. and L.A. Diaz.Anaerobic Biodegradability Test-ing of Surfactants, Chemospilere30(5),813-830 (1995).

21. Larson. R.J., Comparison ofBiodegradation Rates in labora-tory Screening. Studies withRates in Natural Waters, ResidueReviews 85: 159-171 (1983).

22. Larson. R.J.. and R.L. Perry. Useof the Electrolytic Respirometerto Measure Biodegradation inNatural Waters. \Valer ResearchIH97-702 (1981).

23. ASTM Designation: D 2667-89.Standard Test Method forBiodegradability of AlkylbenzeneSUlfonate. Annual Book of ASTMStandards, Vol. 11.05, ASTM.West Conshohocken. Pennsylva-nia.

24. Painter. H.A., and T.F. Zabel.Review of the EnvironmentalSafety of LAS. WRc Report CO/659-M/I/EV 8658, The Euro-pean Centre of Studies on LinearAlkylbenzene and Derivatives(ECOSOL). 1988.

25. OECD Guidelines for Testing ofChemicals. Section 3: Degrodo-non and Accumulation. Summaryof Consideration, Paris, May 12.1981. pp. \-5.

26. Schroder. F.R.. Concentrarions ofAnionic Surfactants in ReceivingRiverine Water, Tenside Surfac-tallt Oetergents 32(6):492-497(1~5). •