Objectives of the Solubility Data Series

Mark Salomon

MaxPower, Inc.

141 Christopher Lane

Harleysville, PA 19438

mark.salomon@maxpowerinc.com

Foreword by A.S Kertes appearing in SDS

Volumes 1-53 (1979-1993).

“If the knowledge is

undigested or simply wrong,

more is not better.”

Presentation Outline

• Introduction to the IUPAC Solubility Data Project

and the IUPAC-NIST Solubility Data Series.

• Format for compilation data sheets.

• Format for critical evaluations

• Examples of smoothing equations used in

regression analyses of data for gas/liquid,

liquid/liquid and solid liquid systems.

• References quoted for this review.

Sources of Solubility Data

• Primary Sources: peer reviewed literature; sheer volume of data

overcomes the capacity of 2o and 3o services to respond

effectively. Some articles in which solubilities are not the main

objective can contain briefly measured, sometimes qualitative

values which find their way into subsequent literature

proliferating the literature with “undigested or wrong” data.

• Secondary Sources: review articles often more specialized and

limited in scope of literature cited, no indication if material has

been excluded by design or less than thorough literature search,

lack detailed analyses of numerical data.

• Tertiary Sources: handbooks, reference books, proprietary

company reports are generally uncritical, limited in literature

survey, neglect error limits and lack references which users might

wish to check.

•

The Solubility Data Project and the Solubility Data

Series

• The IUPAC Solubility Data Project (SDP) addresses the above problems by producing the Solubility Data Series (SDS) in which all available published literature to date on solubility data from all available literature sources for a specific solute/solvent system are precisely detailed on Compilation(data) sheets providing information on materials, experimental methods and errors. Where sufficient literature data exist, contributors to the SDS provide Critical Evaluationscomparing literature data to determine their merits. Data can be classified as rejected when qualitative or incorrect, recommended when agreement between different authors exists, or tentative when sufficient literature comparisons cannot be made.

• Details on preparing Compilations and Critical Evaluations are presented in the following slides.

General Format for Compilations (Data Sheets)

Components:

List of components: formulas, CAR

numbers

Original Measurements:

Citation to the primary source of data

Variables:

Temperature, pressure, concentrations

Prepared by:

Name of Compiler

Experimental Values

Experimental data exactly as they appear exactly in the literature and

converted to various convenient units where appropriate.

Auxiliary Information

Method/Apparatus/Procedure:

Experimental apparatus and methods used to determine solubilities.

Source and Purity of Materials:

Estimated Error:

Either from the primary source or estimated by the compiler.

General Format for Critical Evaluations

Components:List of components: formulas, CAR

numbers

Evaluator:

Name of Evaluator and date of

evaluation

Based on data in the compilations, the Evaluator discusses the data in

terms of experimental methods, purity of materials, reproducibility and

precision or accuracy. If sufficient data exist by different authors, the

Evaluator will produce a set of data based on weighted averages or an

appropriate smoothing equation with estimated standard deviations.

The data in this set are designated as either Recommended or

Tentative. Data that are judged to be of low precision or in error are

either rejected or designated as Doubtful.

Graphical plots of Recommended or Tentative data are given where

appropriate.

Examples of Smoothing Equations used in Critical Evaluations

(mole fraction bases for binary gas/liquid & solid/liquid systems)

1ln 1 ( ) / (1 ) A B Cln Drv v r r v rx x v r r r x T T T

1 = A B Cln DY T T T

Clarke and Glew’s variation* of the van’t Hoff equation for solubilities at constant

pressure is used extensively in the Critical Evaluations;

The solubility function Y is formulated either in mole fraction or molality units. Mole

fraction units are useful for solubilities over the entire composition range from very

dilute solutions, including hydrates, to the melting point of the anhydrous solid in

which case the above equation takes the form (Counioux, Cohen-Adad, Lorimer).

For gas solubilities as a function of pressure at constant temperature,

the following equation has been used (Battino et al.)

2

0 1 2ln A ln / MPa A / MPa A / MPax P P P

*E.C.W. Clarke and D.N. Glew, Evaluation of thermodynamic functions from equilibrium

constants, Trans. Faraday Soc., 62, 539 (1966).

Examples of Smoothing Equations used in Critical Evaluations

(molality bases for binary solid/liquid systems)

A second and equivalent form of the function Y is useful when hydrates are the solid

phase in which case the above equation takes the following form (Counioux, Cohen-Adad, Lorimer, Mioduski et al.)

1 = A B Cln DY T T T

1

0 0ln( / )-( / -1) = A B Cln Dm m m m T T T

Where m0 = 1/rM2 is the molality of a binary salt solvate with M2 the molar mass of the

solvent. This equation is particularly useful to accurately confirm and predict metastable solubilities

before and after congruent melting points. Other complex methods involving equations for

activity coefficients are used providing additional experimental data exist. For example, the

solubilities of the alkaline earth carbonates MgCO3 and BeCO3 utilized the equation

23

2 2 2s c 1 w

1 2

2 M HCO

CO CO CO41 1lg lg lg lg lg lg

mol kg 3 3 atm atm atm

f f fK K K as ca b d T

K T

where Ks is the solubility constant of MCO3, Kc is the solubility constant of CO2, K1 and K2

are the first and second acid dissociation constant of CO2/carbonic acid, f(CO2) is the

fugacity of CO2, and the values are activity coefficients (De Visscher et al.).

Very Old Solubility StudiesSolubilities published even in the first half of the 19th century often compare favorably

with values measured recently and sometimes constitute the only source of data.

Compilations based on these publications not only are possible sources of reliable data

but also are sources for the history of science and technology. Example of a

compilation for NaCl + H2O published in 1885 where solubilities were determined to

be Recommended with experimental methods and purity of materials comparable to

modern standards is summarized in the following 3 slides.

Example of a compilation for NaCl + H2O published in 1885

A / Bln( / ) C DfY T T T T

From R. Cohen-Adad and J.W. Lorimer, Solubility Data Series, Volume 47. For the critical evaluation

of the binary NaCl-water system, 481 data sets fitted by least squares, and after rejecting outliers,

409 data points fitted to the 4-parameter equation to produce a set of Recommended and

Tentative solubilities as a function of temperature.

where Tf is a reference temperature (melting point of the solid phase). Selected results for

data reported by Raupenstrauch in 1885 are shown below.

Examples of Smoothing Equations used in Critical Evaluations

(mole fraction bases for liquid/liquid systems)

(1/3)

1 c,1 1 c 2 c 3 cln ln ( / 1) (1 / ) (1 / )x x b T T b T T b T T

(1/3)

2 c,1 1 c 2 c 3 cln ln(1 ) ( / 1) (1 / ) (1 / )x x c T T c T T c T T

For binary systems where Tc is the upper critical solution

temperature and xc,1 is the corresponding critical mole

fraction, the solubility of liquid 1 in liquid 2 analyzed by

(Góral et al., SDS vol 91) utilized the following equation

The solubility of liquid 2 in liquid 1 is given by

For ternary systems, experimental data were correlated

using the NRTL equation (Góral et al., SDS vol 101 based on

the notation of Renon and Prausnitz, AIChE J. 14, 135 (1968))

åå

å=

3

3

3

R i

k

kki

j

jjiji

i

E

xG

xG

xT

Gt

Future of the SDP

At the present time, 103 SDS volumes have been published and new volumes are in various stages of completion. A number of volumes are quite large and thus have been published in parts in JPCRD bringing the total number of SDS publications to 136.

New contributors to the SDS are warmly welcome, and inquiries can be sent to the following:

• Clara Magalhães, Chair of the Subcommittee on Solubility and Equilibrium Data (SSED). Email: mclara@ua.pt

• Earle Waghorne, SSED secretary. Email: earle.waghorne@ucd.ie

• Mark Salomon, SDS Editor-in-Chief. Email: marksalomon@comcast.net

• Additional information on volumes in preparation is available at the IUPAC web site.

Much of this review was taken liberally from the following publications.

• H.L. Clever, The IUPAC Solubility Data Project. A Brief History:1972-2001. Chem.

Intern., 26, No.3, May-June 2004.

• R. Battino, T.R. Rettich and T. Tominaga, The Solubility of oxygen and ozone in liquids; J.

Phys. Chem. Ref. Data, 12, 163-178 (1983).

• R. Cohen-Adad and J.W. Lorimer, Alkali Metal and Ammonium Chlorides in Water and

Heavy Water (Binary Systems), Solubility Data Series, Volume 47, Pergamon Press, 1991.

• G.T. Hefter and R.P.T. Tomkins, Eds., The Experimental Determination of Solubilities,

Wiley Series in Solution Chemistry, Chichester, UK 2003.

• J.-J. Counioux and R. Tenu, J. Chim. Phys, 78, 815 and 823 (1981).

• R. Cohen-Adad, Pure Appl. Chem., 57, 255 (1985).

• R. Cohen-Adad, J. W. Lorimer, S. L. Phillips, and M. Salomon, A Consistent Approach to

Tabulation of Evaluated Solubility Data: Application to the Binary Systems RbCl-H2O and

UO2(NO3)2-H2O, J. Chem. Inf: Comput. Sci. 35, 675-696 (1995).

• T. Mioduski, C. Guminski and D. Zeng, IUPAC-NIST Solubility Data Series. 87. Rare

Earth Metal Chlorides in Water and Aqueous Systems. Part 1 Scandium Group (Sc, Y, La),

JPCRD 37, 1765 (2008).

• A. De Visscher et al., IUPAC-NIST Solubility Data Series. 95 . Alkaline Earth Carbonates

in Aqueous Systems. Part 1. Introduction, Be and Mg. JPCRD 41, 13105 (2012).

• M. Góral, D. G. Shaw, A. Maczynski and B. Wisniewska-Goclowska, IUPAC-NIST

Solubility Data Series. 91. Phenols with Water. Part 1. C6 and C7 Phenols with Water and

Heavy Water, JPCRD 40, 033102 (2011).