23327746-DK1288-Appendix

AppendixAppendix

A. FUNDAMENTAL CONSTANTS, BASIC ANDDERIVED SI UNITS

A.1 Fundamental Constants

A.2 Fundamental SI Units

Physical quantity Symbol Unit name Symbol

Length l meter m

Mass m kilogram kg

Time t second s

Electric current I ampere A

Thermodynamic

temperature

T Kelvin K

e electron (proton) charge, 1.6022 10�19 coulomb (C)

F Faraday constant, 96,485Cmol�1

NA Avogadro number, 6.022 1023mol�1

kB Boltzmann constant, 1.3807 10�23 joule/kelvin (J K�1)R molar gas constant, 8.314 JK�1mol�1 (0.08206 L atm mol�1 K�1)vM molar volume of ideal gas, 0.02241m3mol�1

715

Copyright © 2004 by Taylor & Francis Group, LLC

A.3 Derived SI Units as Used in Chemistry

B. SYMBOLS USED IN CHEMICAL REACTIONFORMULAS

Attempts have been made to adhere to the following set of abbreviations forthe reacting species to simplify their identification:

Ionic charges are omitted, when not necessary for understanding.Other abbreviations commonly used:

Physical quantity Symbol Unit name, symbol, explanation

Physical mass (weight) m(w) gram, g; mA is weight of pure substance A

Molar mass M molecular weight in atomic mass units (amu)

Amount of substance n moles, mol; nA =mAMA

1 mol =NA molecules

Volume V liter, L, or dm3 (SI-unit is m3)

Concentration c or [ ] molarity, M, mol L�1, or mol dm�3

Density r g/cm3 = 103 kg/m3 (SI unit is kg/m3)

Pressure P megapascal, MPa; 1 atm= 0.1013MPa; 1 bar =

0.1MPa

Temperature T 8C degrees Celsius; 0 T8C= 273.15K

Energy E joule (watt seconds, Ws) J; 1 kilocalorie

(Kcal) = 4.187 J; 1 electron volt (eV) =

1.602 2 10�19 J corresponds to 96.485 kJ

mol�1

M metal ion (central atom)

A (preferably lipophilic) extractant anion (anion of HA)

L (preferably hydrophilic) ligand in aqueous phase (monobasic)

X any (likely noncomplexing) anion in aqueous phase

B uncharged donor molecule (adduct former)

S organic solvent molecules (solvating or nonsolvating)

A, B, C for various solutes in general

Az� anion in general, charge z� (may be omitted)

Cz+ cation in general, charge z+ (may be omitted)

Cn+An� electrolyte in general, with n+ atoms of C and n� atoms of A in

a neutral salt (e.g., NaCl or NaClO4).

e, and ne for electrolyte and nonelectrolyte, respectively


Physical state:

Gaseous (g)Solid (s)Liquid (l), not recommended in this textAqueous [i.e., dissolved in water (aq)]Organic [i.e., dissolved in organic solvent (org); not recommended (s)]Water (w), to specifically refer to water molecules

B.1 Abbreviations for Organic Compounds

AA: acetylacetone; 2,4-pentanedioneBA: benzoylacetoneDCTA: 1,2-diaminocyclohexane tetraacetic acidDBP: dibutyl phosphoric acidDTPA: diethylenetriamine pentaacetic acidDEHPA: di-2-ethylhexyl phosphoric acidPC88A: (and Ionquest 801) 2-ethylhexyl phosphonic acid 2-ethylhexyl esterEDTA: ethylene diaminetetraacetic acidFAA: hexafluoroacetylacetoneHIBA: a-hydroxyisobutyric acidLIX64: o-hydroxybenzophenone oximeNTA: nitrilotriaminoacetic acidTTA: thenoyltrifluoroacetoneTOA: trioctylamine; Aliquat-336 is mainly TOATDA: tridecylamine; Adogen 464 is C8–C10 amineTLA: trilaurylamine; C12

TBP: tributyl phosphateTOPO: trioctylphosphine oxideRNH+

3: organic primary ammonium ionR2NH+

2: organic secondary ammonium ionR3NH+: organic tertiary ammonium ionR4N

+: organic quaternary ammonium ionR: organic radical in general

Protolytic compounds are written as monobasic acids (e.g., HA), butthe proton may be excluded as an abbreviation (e.g., TTA or EDTA). Forexample, in the text HTTA and TTA may mean the same if not specified, asby the reaction HTTA ! H++TTA�.


C. TERMINOLOGY FOR SOLVENTEXTRACTION EQUILIBRIA

Most chapters in this book use the following symbols, which follow IUPACrecommendations (see Refs. 1–4) where such recommendations are avail-able.

C.1 Reference to Aqueous and Organic Phases

In the reaction below a metal ion Mn+ reacts with n ligand anions L� toform an uncharged complex MLn. If the ions dissolve only in the aqueousphase, and the metal complex and undissociated acid HL dissolve only inthe organic phase, IUPAC allows the reaction to be written in four differentways:

Mnþ(aq)þ nHL(org)ÐMLn(org)þ nHþ(aq) Kex (C.1a)

Mnþaq þ nHLorg ÐMLn;org þ nHþaq Kex (C.1b)

Mnþ þ nHL(org)ÐMLn(org)þ nHþ Kex (C.1c)

Mnþ þ nHLÐMLn þ nHþ Kex (C.1d)

Kex is the overall extraction constant [2]. Different authors favor differentnotations, all being used here (as in other literature). For example, the con-centration of HL in the organic phase may be written ½HL�, [HL]org, or [HL]o,and in the aqueous phase [HL] (with no index), [HL]aq or [HL]a. Freiser andNancollas [2] recommend against the combination [HL]o/[HL]a, whichinvites confusion.

Total concentration of species A in a phase is indicated either by [A]t,[A]tot, or cA. ‘‘Original’’ value (e.g., total weight of substance, volume, con-centration, or such, in the beginning of an experiment) may be indicated byan upper index 0 (e.g., [A]0 or cA

0. Total concentration and original con-centration may mean the same.

C.2 IUPAC Terminology

IUPAC prefers ‘‘liquid–liquid distribution’’ or ‘‘liquid–liquid extraction’’rather than ‘‘solvent extraction.’’ We justify our preference for ‘‘solventextraction’’ by its more common usage. IUPAC defines the following terms:

Distribution ratio is the ‘‘total analytical concentration of a substancein the organic phase to its total analytical concentration in the aqueousphase, usually measured at equilibrium.’’ Symbol D. D shall be defined and,preferably, specified by an index; if the distribution of mercury is measured,the distribution ratio is written D(Hg) or DHg. The term ‘‘partition ratio’’ isnot used for the distribution ratio.


Distribution constant is symbolized by KD. Thus for

A(aq)Ð A(org);KD;KD(A);KD;A;KDA; or KDR ¼ ½A�org=½A�aqMAz(aq)ÐMAz(org);KD;KD(MAz);KDMAz; or KDC ¼ ½MAz�=½MAz�

In this book we prefer a suffix to the index to identify if the distributionconstant refers to the neutral reagent (or extractant) or to the unchargedmetal complex (i.e., KDR and KDC, respectively).

Extraction equilibria (including adduct formation) must be defined bytext, for example,

Mnþ þ nHA(org)þ aS(org)ÐMAnSa(org)þ nHþ Kex

Recovery factor is defined as the percentage (R%), or fraction R, of thetotal quantity of a substance extracted under specified conditions. (In ourtext we also use percentage extraction, E%.)

Solvent is ‘‘a liquid phase (usually an organic liquid) or the solution ofan extractant in an organic diluent which is used to extract a substance fromanother liquid (usually aqueous).’’

Diluent is ‘‘an inert (organic) solvent used to improve the physicalproperties (density, viscosity, etc.) or the extractive properties (e.g., selec-tivity) of the extractant. The diluent has negligible extractant properties forthe substance to be extracted.’’

Extractant is ‘‘the reagent which forms a complex or other adduct inthe solvent with the substance which partitions across the phase boundary ofthe extraction system. The extractant (extracting agent) may also partition.’’

Extract is ‘‘the separated phase (usually organic) containing the sub-stance extracted from the other phase.’’

Stripping is ‘‘the process of back-extraction of the distribuend from theextract (usually into the aqueous phase).’’

Distribuend is ‘‘the substance that is distributed between two immis-cible liquids or liquid phases.’’

C.3 Complex Formation in Aqueous Solutions

The nomenclature used in this book is presented in section 3.1. It should benoted [2] that ‘‘For polynuclear complexes and complexes with several kindsof ligands, it may sometimes be practicable to use b with . . .multiple sub-scripts. Their general meaning must then be defined very clearly with a fullreaction formula. . . . Strict standardization in this field has not yet beenachieved.’’


C.4 Other Equilibrium ConstantsCommonly Used in This Text

D. FORMULA STRUCTURES

Structural formulas of a number of commonly used extractants, and sometypical chelate compounds.

QM distribution ratio of M between nonaqueous and aqueous phase

DM distribution ratio of M between organic solvent and aqueous phase

(e.g., DLa for distribution of element La)

Ki stepwise formation constant for ith complex (e.g., MLi)

Kex overall extraction constant

Ka acid dissociation (concentration) constant; pKa =�log Ka

Kal first acid dissociation constant for multibasic acid

Kadl first adduct formation constant (organic phase)

KDx distribution constant for x (specified); for example, x =R, or =HA,for undissociated extractant (reagent), = C for neutral

(e.g., metal-containing) complex

Ksp solubility product

Kw ionic product of water

bn overall complex formation, or stability, constant for formation of nthcomplex (e.g., MLn).

P thermodynamic distribution constant

sAC solubility of AC in moles or grams per liter (mL�1 or gL�1)Kass association constant for ion pair formation

KBS Bunsen coefficient for solubility of gas in a liquid

1. Dinonylnaphtylsulfonic acid 2. Benzoic acid

3. Salicylic acid 4. Isopropyltropolone


5. b-Diketones:(a) ketoform; (b) enol form; (c) enolate ion;

(d) acetylacetone, 2,4-pentanedione, HAA: R =R0 =CH3;

(e) trifluoroacetylacetone, HTFA: R =CH3, R0 =CF3;

(f) benzoylacetone, HBA: R =CH3, R0 =C6H5;

(g) thenoyltrifluoroacetone, HTTA: R = formula (g), R0 =CF3;(h) bis-acetylacetonatocopper(II) complex; and

(i) dibenzoylmethane: R =R0 =C6H5.

6. 8-Hydroxoquinoline, oxine 7. 1-Nitroso-2-naphthol


8. Oxime: R and R0 are different long-chained

and branched aliphats or aromates

9. N-Phenylbenzo-hydroxamic acid

10. N-Nitrosophenylhydroxylamine

(ammonium salt is cupferron)

11. (a) Amide R=R0 =R@= alkyl; and(b) carbamoylphosphinate: R1 =R2 = alkyl, R = phosphinate

12. Carbamoylmethylene phosphonate 13. Dialkyl phosphonate


14. Di(2-ethylhexyl) phosphoric acid, HDEHP, D-2EHPA; R is C8H17:

(a) monomeric form;

(b) dimeric form;

(c) M(HA2)3 complex formed with M(III); and

(d) UO2(HA2)2 complex.

15. Tributylphosphate, TBP 16. Trioctyl phosphine oxide, TOPO

17. Methyl isobutyl ketone, MIBK, hexone 18. o-Phenanthroline


REFERENCES

1. Hogfeldt, E. Stability Constants of Metal-Ion Complexes. Part A: Inorganic

ligands; IUPAC Chemical Data Series No 22; Pergamon Press: New York, 1982.

2. Freiser, H.; Nancollas, G. H. Compendium of Analytical Nomenclature. Definitive

Rules 1987; IUPAC; Blackwell Scientific Publications (www.IUPAC.com/

publications): Oxford, 1987.

3. McNaught, A. D.; Wilkinson, A. IUPAC Compendium of Chemical Terminology,

2nd Ed.; Blackwell Science, 1997.

4. IUPAC. Quantities, Units and Symbols in Physical Chemistry, 2nd Ed.; Blackwell

Science, 1993.

19. Dialkyl dithiophosphonic acid 20. Diethyl dithiocarbamate

21. Crown ethers:

(a) dicyclohexyl-18-crown-6, DC18-C6; and

(b) 15-crown-5, 15-C5


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23327746-DK1288-Appendix