ATHIAS — An information system for abiotic transformations of halogenated hydrocarbons in aqueous solution

Chemosphere, Vol.17, No.2, pp 331-344, Printed in Great Britain

1988

0045-6535/88 $3.00 + .O0 Pergamon Journals Ltd.

ATHIAS - AN INFORMATION SYSTEM FOR ABIOTIC TRANSFORMATIONS OF HALOGENATED HYDROCARBONS IN AQUEOUS SOLUTION Waltraud EUenrieder and Martin Reinhard EnvironmentalEngineering and Science Civil Engineering Department Stanford University, Stanford, CA 94305

ABSqllACT The kinetic data for the transformation reactions of haloaliphatic compounds in water have been critically reviewed. The kinetic constants have been compiled in ATHIAS, a microcomputer based Lotus 1-2-3 worksheet which also contains literature citations, compound characteristics and reaction products. For facile data evaluation, the worksheet has been equipped with programs (i) for rapid retrieval of data normalized to standard conditions, and (ii) for interactive data evaluation under user-specified temperature and pH conditions.

INTRODUCTION Halogenated aliphatic hydrocarbons may be transformed in pure aqueous solution either via hydrolysis to alcohols or via elimination to alkenes [1- 5]. Transformation rates vary greatly and depend on substrate structure, temperature, and pH. The reported data have been compiled and reviewed [1,6- 9]. Most transformation rates are very slow at environmental temperatures (T = 5-30oc) with half-lives of months to years. Reliable measurement of such slow reactions is difficult, even under controlled laboratory conditions. Therefore, rates have generally been measured at elevated temperatures where reactions are faster. To estimate environmental half-lives from high temperature data, equations describing the temperature-dependence of the rate constants must be known. Similarly, reaction rates may depend on solution pH in the environmentallyrelevant pH range (pH 6 to 9) and rate laws that consider pH-dependence must be known to calculate half-lives at specific pH values. The retrieval of kinetic data and the correction for environmental conditions are time-consuming tasks. Rate data have been measured over a wide range of temperature and pH conditions. Different mathematical equations of varying complexity have been developed to describe the dependence of transformation rates on temperature and pH.

331

332

To facilitate the retrieval and estimation of environmentalhalf-lives for halogenated aliphatic compounds, we have developed the microcomputer-based information system ATH]AS (Abiotic Transformations of Halogenated Hydrocarbons In Aqueous Solution), which integrates a conventional data base containing kinetic constants and equations with easy-to-use system functions. These system functions permit the user to access and evaluate the data rapidly and interactively. Specifically, ATHIAS has been designed to serve the following purposes: (i) storage and convenient retrieval of compound characteristics, (ii) storage of equations describing reaction rates and half-lives as a function of temperature and solution pH, (iii) display of reaction rates and reaction products under standard conditions (pH 7 and 25oc), and (iv) interactive computation of reaction rates and half-lives at any other specified pH or temperature. The system includes kinetic data that have been reported since 1960. The data base was developed for aliphatic halocarbons CmHnXo (X = F, C1, Br, I) and is limited to data measured in strictly aqueous buffer solutions.

MECHANISTIC CONSIDERATIONS Transformation Pathways The reactions considered here include nucleophilic substitution with the water molecule or the hydroxide ion as the nucleophile (also referred to as hydrolysis), and elimination of HX with the water molecule or the hydroxide ion as the base (also known as dehydrohalogenation). If the water molecule is the dominant nucleophile or base, the process is termed neutral, if the hydroxide ion is the dominant nucleophile or base, the process is termed basepromoted. Acid promotion has not been observed, i.e. the hydronium ion has not yet been found to react with halogenated aliphatic hydrocarbons in aqueous solution [ 1]. Scheme I

R ~. R'-C-X R. /

SN1/SN2 + H20/OH-

R ,~ I= R ' - C - O H R. /

+ HX

Scheme II

.9.x

,x ~" R- C R -' H CHII-

/

s.1 .2

R-C-C-R'

~ R-

H~

SN~S~/J + H20/OH'~X ~ El/E2

H

R'

H

÷ R'

X'

%.Z

R'

333

Hydrolysis of a monohalogenated aliphatic hydrocarbon compound (Scheme I) may proceed via one of two basic mechanisms. For a unimolecular, two-step nucleophilic substitution reaction (SN1), the halogen atom is first cleaved off in the rate limiting step and the resulting carbonium ion reacts with H20 or OH- in a rapid second step [10,11]. Alternatively, a one step bimolecular nucleophilic substitution reaction (SN2) may take place in which the scission of the carbon-halogen bond and the formation of the carbon-oxygen bond occur in one concerted step [ 10,11]. Nucleophilie substitution of haloaliphatic compounds generally follow the SN2 mechanism, except for the sterically- hindered tertiary halocarbons, such as tertiary butylchloride. In addition to hydrolysis, halogenated aliphatic hydrocarbons may react via elimination of HX to form an alkene (Scheme II) [2-5,12]. As with the SN1 reactions, elimination reactions may proceed via either a two step unimolecular mechanism (El) or a one-step bimolecular one (E2). In El, the halogencarbon bond is cleaved off in the initial rate-limiting step. The second step is a fast abstraction of a beta proton from the resulting carbonium ion by a base (H20 or OH-) [10,11]. In the bimolecular E2 reaction, the cleavage of the carbon-halogen bond and abstraction of the beta-proton occur in a concerted, one-step process [10,11]. Eliminations of HX from haloaliphatic compounds generally follow the E2 mechanism. In general, hydrolysis is more rapid than elimination for compounds having a low number of halogens. Conversely, elimination rates increase as the number of beta halogens increases [13].

Rate L a w s

Both nucleophilic substitution and elimination reactions are generally first order with respect to the substrate concentration:

-d[RX]/dt = k [RX]

(1)

where k represents the rate constant for nucleophilic substitution or elimination, k S or k E, respectively. Hence, for substrates which react via both substitution and elimination simultaneously, the overall rate constant k o v , is

kov = k S + kE

(2)

Both nucleophilic substitution and elimination may react via the neutral or the base-promoted process. Therefore, the rate laws include two terms, one for the neutral and one for the base-promoted process:

s

k S = k B [OH-]+k~

(3)

kE = k eB [OH-] + kN

(4)

334

where k S and kE are the overall rate constants for nucleophilic substitution and elimination, respectively, k~ and kB are second-order rate constants for the base-catalyzed nucleophilic substitution and elimination reactions, and k~ and kN are the pseudo-first-order rate constants for the neutral nucleophilic substitution and elimination reactions. Neutral reactions are pseudo-first- order because the water concentration remains constant. By considering Kw = [H+] [OH-], where Kw is the autoprotolysis constant of water, the overall rate equations (3) and (4) for nucleophilic substitution and elimination may be written as functions of pH:

k S = kB Kw/10-pH + k~q

(5)

k E = kB Kw/10-PH + kN

(6)

Hence, five constants must be known in order to compute the transformation by nucleophilic substitution and elimination (Scheme II) as a function of pH at constant temperature. Additional terms need to be considered if more than two different products are formed. Transformations may be dominated either by the neutral or the base- promoted process, depending on the relative magnitude of kN and kB[OH-]. By setting kN equal to kB[OH-], we may calculate the pH value where both processes are equally fast. This pH value, termed INB, is obtained from

INB = log[kN / kB Kw]

(7)

Thus, if the solution pH is below INB, the neutral process is dominant, and the rate is independent of pH. Conversely, if the solution pH is above INB, the base-promoted process is dominant and the rate increases with the hydroxide ion concentration. Generally, INB is compound dependent. However, for nucleophilic substitution of most halocarbons, INB is above the environmental pH range (pH 6 - 9). Thus under environmental conditions, rates of these reactions are generally pH-independent. For some elimination reactions, however, such as the dehydrohalogenation of 1,1,2-trichloroethane [3], 1,1,2,2-tetrachloroethane [4], and 1,2-dibromo-3-chloropropane [2], INB lies within the pH-range 5-7. For these compounds, then, rates are dependent upon pH under environmental conditions.

335

The parameters k N, k B and Kw of Equations 5 and 6 are all functions of temperature, leading to increasing reaction rates with increasing temperature. The following Equations (8-10) have been used to describe the temperature- dependence of k:

log k = log A - EA/2.303 R T

(8)

(the Arrhenius Equation) where k is the rate constant ([1/sec] for unimolecular constant, [l/mol sec] for bimolecular constant), A is the pre-exponential factor, EA is the Arrhenius activation energy [kJ/mol] [14], R is the universal gas constant [kJ/deg mol] and T the temperature [K];

log k = -A / T + B log T + C

(9)

where A, B and C are experimentally determined constants [15]; and

log k = -A H*/R T + A S*]R + log T + 10.32

(10)

where A H*(T2) = A H*(T1) + A Cp (T2 - T1) A S*(T2) = A S*(T1)- A Cp 2.303 log (T1/T2)

A H*(T2) is the enthalpy of activation [kJ/mol] at temperature T2, A S*(T2) the entropy of activation [kJ/deg mol] at temperature T2 and A Cp the heat capacity [kJ/deg mol]. A H*(T1) is the enthalpy of activation at a known reference temperature and A S*(T1) the entropy of activation at a known reference temperature. Equation 9 is a purely empirical equation, whereas Equation 10 is based on transition state theory [14].

336

THE INFORMATION SYSTEM ATHIAS Description of ATHIAS ATHIAS has been created as a Lotus 1-2-3 worksheet [16]. A 1-2-3 worksheet is organized as a table of columns and rows designated by letters and numbers, respectively. The intersections of the columns and rows are called cells. Cells are the smallest units of the worksheet and are identified by their column/row coordinates. Four different kinds of data may be stored in cells: text, numbers, mathematical formulas and instructions written in the

1-2-3 macro command language [ 17,18]. ATHIAS consists of two separate parts: (i) a data base containing compound characteristics, data and functions describing pH-.and temperature- dependence of the reaction rates and half-lives, reaction products and literature references; and (ii) programs written in the 1-2-3 macro command language called system functions. System functions have been designed to lead the user through a series of clearly specified, self-guided steps to retrieve and evaluate data listed in the data base. Knowledge of the familiar Lotus operations is the only pre requisite for the use of ATHIAS.

The dam base The data base of ATHIAS is located in the upper-left comer of the worksheet and covers columns A through BS and rows 1 through 150, a total of 9900 cells. The data base is organized as indicated in Table 1. Table 1.

Information summarized in the database of ATHIAS and corresponding columns CATEGORY

COLUMNS

INFORMATION

Compound Characteristics

A-F

Compound-name, number, flag for recommended value, formula and CAS registry number;

Substitution

G - AI

literature values of ks and k~; temperature-functions of kl~ and k~, comment, references; pH-functions of kg and INB, comment, references;

S,k~ , kS and tla

calculated values of k N

at 25 °C and pH 7;

substitution product; Elimination

AJ - BL

literature values of k~ and k~ ; temperature-functions of kl~ and k~, comment, references; pH-functions of k~ and INB, comment, references; calculated values of kl~I , k~, k E and tit 2 at 25 °C and pH 7; elimination product;

Substitution and

BM - BQ

Elimination Literature Reference

calculated value of kov of substitution and elimination at 25 °C and pH 7;

BR - BS

reference number and full literature references;

337

Rows contain information pertaining to one particular compound, given in column A. Different studies of the same compound are listed in subsequent rows. Each column contains one specific item of information, as indicated by the column heading in the top cell of the column. Columns A through F contain compound-specific information, i.e., name, entry-number, flag indicating a recommended value, molecular formula and CAS registry number. Columns G through AI, AJ through BL and BM through BQ contain the kinetic data for nucleophilic substitution, elimination and overall process, respectively. The kinetic data summarized in the data base are stored as mathematical equations describing the temperatureand/or pH-dependence of the particular rate-constant (see Equations 2-10). However, when using ATHIAS, only numerical results are displayed. Mathematical equations are invisible to the user. If available the temperature-dependence described in the original literature reference was implemented. Otherwise, an Arrhenius relationship (Equation 8) was used, assuming an activation energy of 100 kJ/mol. This value is typical for aqueous reactions of haloaliphatic compounds [8]. To calculate the value of Kw at different temperatures, the Robinson equation [19] was used. Presently, ATHIAS contains kinetic data on 58 compounds with up to five different sets of literature values per compound. These compounds are listed in Table 2. Table 2.

Summary of compounds listed in ATHIAS

Methyl Chloride Methylene Chloride Chloroform Ethyl Chloride Vinyl Chloride 1,2-Dichloroethane 1,1,1 -TricNoroethane 1,1,2-Trichloroethane 1,1,2-Trichloroethylene 1,1,1,2-Tetrachloroethane 1,1,2,2-Tetrachloroethane Pentachloroethane i-Propyl Chloride Allyl Chloride 1,2,3-Trichloropropane 2,2-Dichloropropane t-Butyl Chloride cis1,4-Dichloro-2-butene trans1,4-Dichloro-2-butene t-Pentyl Chloride Hexachlorocyolopentadiene 1,2,3-Trichlorobenzene 1,2,4-Trichlorobenzene Benzyl Chloride Dichloromethylbenzene Benzotrichloride p-Methylbenzylohloride

Methyl Bromide Ethyl Bromide 1,2-Dibromoethane n-Propyl Bromide i-Propyl Bromide Allyl Bromide 1,2-Dibromopropane 2,2-Dibromopropane 1,3-Dibromopropane 2,3-Dibromo-l-propene 2CI,2-Bromopropane 2-Bromo-3-chloro-1 -propene 1,2-Dibromo-3-chloropropane i-Butyl Bromide t-Butyl Bromide neo-Pentyl Bromide Cyclopentyl Bromide n-Hexyl Bromide 3-Bromohexane Cyclohexyl Bromide n-Heptyl Bromide Benzyl Bromide p-Methylbenzylbro mide o-Methylbenzylbromide n-Bromopropylbenzene

Methyl Iodide Ethyl Iodide i-Propyl Iodide Allyl Iodide Methyl Fluoride t-Butyl Fluoride

338

The reported studies vary greatly in detail and scope. In general limited data are available on pH- and temperature-dependence, and relatively few studies have identified products and established mass balances. Moreover, rate constants reported by different investigators often differ significantly. For compounds with multiple entries, we have identified "recommended" data by comparing the quality of the experimental protocols. The following criteria have been applied to compare the quality of reported data: (1) Data measured under environmental conditions (with respect to temperature, pH, ionic strength) have been preferred over those data which have been measured under conditions significantly different from those encountered in the environment. (2) Studies where the rates of product formation were reported have been preferred over those where only an overall reaction rate was reported. (3) Studies which report the degree of control over reaction conditions (e.g., error limits for temperature or pH) have been preferred over those where such information has not been provided.

The System Functions System functions are programs written in 1-2-3 macro command language for (i) facile and rapid information retrieval and (ii) interactive data evaluation. The system functions are stored in the worksheet area outside the data base and are automatically invoked during loading of the worksheet into Lotus. The system functions are hierarchically organized (Figure 1). Self-explanatory menus and/or on-screen instructions describing available system functions are displayed at every level of operation. Each system function can be invoked either by entering the corresponding menu command or a keystroke described on the screen.

lsT~.'rlEX,TI I I

PRIWrlENVmONt~Em'ALQurr

[

[.u.~u,,o.

I

I

~.....,,o.

I

I

''"M"

"''1/

I

.oT.

I

I

I T~M"~"ATO"+"IOOT+O'TIITEM"~"ATU"++O~IQu'TIIT~""~"~U"+"I "OT+ uIT I

Figure 1. Hierarchical organization of the menus and on-screen instructions in ATHIAS

QUIT

I

339

System

Functions

for Data

Retrieval

System functions for information retrieval provide access to information stored in the data base. This procedure corresponds to the traditional use of tables which display fixed values for standardized conditions. System functions for data retrieval may be used to access the following information: names of compounds included in ATHIAS,

-

- CAS registry number for a specified compound, - half-life and reaction rates under standard conditions (25°C and pH 7) - reaction products of a specified compound, -

flags for recommended data, and

-

literature reference for kinetic data.

An example for retrieval of the information and literature references of 1,1,1-trichloroethane is displayed in Figure 2.

NAME l,l,l-Trichloroethane MARK FLAG 52 53 54 56 57 * 61

MARK 52 52 53 54 54 56 56 57 57 61 61

tl/2 S [y] 4.7E-~1 4.5E-~1 6.8E-~1 1.7E+~ 1.2E+Ofl 9.1E-01

REG-NUM 71-55-6 tl/2

E[y]

8.7E+~0 4.8E+0~ 217E÷0~

tl/2

S+E [ y ] PRODUCTS 4.7E-~1 A c e t i c Acid 4.5E-~I &.8E-~I PRODUCT E 1.4E+00 1 , 1 - D i c h l o r o e t h y l e n e 9.&E-01 &.8E-~I

REFERENCE W.L. DILLING,N.B. TERFERTILLER,G.J. KALLOS,ENV. SCI. TECH. 9,833 (1975) R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. J . OF CHEM. KIN. V I , 777 (1974) R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. J . OF CHEM. KIN. V I , 777 (1974) W. MABEY,T.MILL,V.BARICH,18&TH ACS-MEETING,AUG28-SEP2,WASHINGTON DC(1983) R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. 3. OF CHEM. KIN. V I , 777 (1974) T.M. VOGEL,P.L. MCCARTY,JOURNAL OF CONTAMINANT HYDROLOGY, 1, 299 (1987) R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. J . OF CHEM. KIN. V I , 777 (1974) T. MILL, W. HAAG, PERSONAL COMMUNICATION R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. J . OF CHEM. KIN. V I , 777 (1974) P.V. C L I N E , J . J . DELFINO,194TH ACS-MEETING,AUG30-SEP4,NEW ORLEANS LA(1987) R.WALRAEVENS,P.TROUILLET,A.DEVOS,INT. J . OF CHEM. KIN. V I , 777 (1974)

Figure 2. Display for 1,1,1-Trichloroethane including full references

340

Information is retrieved from the system by entering a compound name. If the chosen compound is listed in the data base, the system displays the CAS registry number, the compound-number (listed in the column MARK), the recommended citation (signaled by a star in the column FLAG), and the listed half-lives and transformationproducts for substitution and/or elimination at the standard conditions 25oc and pH 7.

System Functions for Interactive Data Evaluation

System functions for interactive data evaluation provide the possibility to select a particular set of kinetic data to calculate rate constants and half-lives for a particular compound at user specified temperature and/or pH conditions. System functions for interactive data evaluation provide the following computational capabilities: - neutral, basic and overall rate constants for nucleophilic substitution and/or elimination and if applicable the

overall reaction in the temperature range 5°-30°C at pH 7; neutral, basic and overall rate constants for nucleophilic substitution and/or elimination and if applicable the overall reaction in the temperature range 5°-30oc at any pH specified; or neutral, basic and overall rate constants for nucleophilic substitution and/or elimination and if applicable the overall reaction at any specified temperature and any specified pH. The capabilities of the system functions for evaluating data and the resulting displays are illustrated in Figures 3 through 5 using 1,1,1-trichloroethane as an example. In Figure 3 the evaluation of the temperature-dependence for 1,1,1-trichloroethane is shown. The temperature-dependence is calculated in steps of 5oc in the environmentally relevant temperature range 5o- 30oc. Displayed are the neutral, basic and overall rate constants for substitution and elimination. The basic rate constant for elimination is not displayed because of a lack of literature data. Additionally the overall rate for both substitution and elimination and the half-life in years is displayed. Name: T [C] 5.00 10.00 15.00 20.00 25.00 30.00 kN(T) E [l/s] 1.5E-10 3.7E-10 8.7E-I~ 2.0E-~9 4.&E-09 1.0E-08

l,l,l-Trichloroethane pH 7.00 7.00 7.00 7.~0 7.00 7.00 kB(T) E [I/mol s]

kN(T) S [l/s] 5.9E-10 1.5E-09 3.5E-09 8.1E-09 1.8E-08 4.0E-08 kH E [l/s] 1.5E-10 3.7E~10 8.7E~10 e.OE-09 4.&E-09 1.0E-08

kB(T) S [1/mol s] 2.4E-09 5.1E-~9 1.1E-08 2.eE-e8 4.3E-08 8.4E-08 tl/2 E [y] 1.5E+02 &.OE+01 2.5E+01 1.1E+01 4.8E+00 2.2E+0~

kH S [l/s] 5.9E--10 1.5E-09 3.5E-09 8.1E-09 1.8E-08 4.0E-08 kH S+E [l/s] 7.4E-10 1.8E-09 4.4E-09 1.0E-08 2.3E-08 5.0E-08

tl/2 S [y] 3.7E+01 1.5E+01 6.3E+~ ~.7E+00 1.eE+~ 5.5E-01 tl/2

S+E [y] 3.0E+~I 1.2E+01 5.~E+0~ 2.eE+~ 9.bE-01 4.4E-~1

Figure 3. Rate constants and half-life of 1,1,1-Trichloroethane in the temperature range 5o-30oc at pH 7

341

In Figure 4 the results of the calculation of the pH-dependence is shown. The pH dependence is calculated in steps of 5°C in the temperature range 5 °- 3 0 o c at a selected pH (5.5). The neutral, basic and overall rate constants for substitution, elimination and the overall rate constant for both substitution and elimination and the half-life in years are displayed at the pre set temperatures and at the chosen pH.

Name:

1,1,1-Trichloroethane

T [C] 5.00 10.00 15.00 20.00 25.00 3~.00

pH 5.50 5.50 5.50 5.50 5.50 5.50

kN
kB(pH) E El/s]

kN(T) S [l/s] 5.9E-10 1.5E-09 3.5E-09 8.1E-09 1.8E-08 4.0E-08

kB(pH) S [l/s] 1.4E-18 4.&E-18 1.5E-17 4.bE-17 1.4E-I& 3.gE-1&

kH S [l/s] 5.9E-10 1.5E-09 3.5E--09 8.1E-09 1.8E-08 4.0E-08

ti/2 S [y] 3.7E+~I 1.5E+01 &.3E+00 2.7E+00 1.2E+0~ 5.5E-01

kH E [I/s] 1.5E-10 3.7E-10 8.7E-10 2.0E-09 4.&E-09 1.0E-08

tl/2 E [y] 1.5E+02 b.OE+OI 2.5E+01 1.1E+01 4.8E+00 2.2E+00

kH S+E [l/s] 7.4E-10 1.8E-09 4.4E-09 1.0E-08 2.3E-08 5.0E-08

t l / 2 S+E [y] 3.0E+01 1.2E+01 5.0E+~0 e.2E+~O 9.&E-01 4.4E-01

Figure 4. Rate constants and half-life of 1,1,1-Trichloroethane in the temperature range 5o-30oc at pH 5.5

In Figure 5 the calculated rate constants and half-life at a specified temperature and pH are shown. Upon entering a chosen temperature and pH - in this case 6 0 o c and pH 9 - the corresponding rate constants are calculated and displayed. Name: T [C] 60.00 kN(T) E [l/s] 6.805E-07

1,1~l-Trichloroethane pH 9.00

kB(pH) E [l/s]

kN(T) S [l/s] 2.7E-06 kH E [l/s] &.8E-07

kB(pH) S [l/s] 2.9E-10

kH S [l/s] 2.7E-06

tl/2 E [y] 3.2E-02

kH S+E [I/s3 3.4E-O&

Figure 5. Rate constants and half-life of 1,1,1-Trichloroethane at 6 0 o c and pH 9

tl/2 S £y] 8.1E-03 tl/2

S+E [y] b.5E-03

342

SUMMARY The described microcomputer-based system ATHIAS combines a Lotus 1-2-3 data base with functions that permit both data retrieval and data evaluation. The data base of ATHIAS contains (i) compound characteristics, (ii) kinetic data for the abiotic decomposition of halogenated aliphatic compounds in aqueous solution, (iii) the mathematical equations for the temperature- and pH-dependence of the rate data and (iv) literature citations. Furthermore, the quality of the literature data has been evaluated, and recommended data flagged for each compound. Easy-to-use system functions are incorporated in ATHIAS for rapid data retrieval and data evaluation. These system functions provide a tool to access rapidly the stored information at standard conditions (25°C and pH 7) and to calculate the listed kinetic data at any specified condition (any temperature any pH). The system is menu-driven and provides self-explanatory on-screen instructions at every level of operation. Knowledge of the familiar Lotus instructions is the only prerequisit for using the system.

To date, the data base in ATHIAS contains data for 58 different haloaliphatic compounds. The system may be updated by adding new data in seperate rows of the data base. ATHIAS is designed to include up to 250 entries. The system can be used on IBM - PC, XT, AT or compatible microcomputers with 512 K memory and LOTUS 1-2-3 version 2.01 installed [16]. ATHIAS is available from the Software Distribution Center, Office of Technology Licensing, 350 Cambridge Ave, Suite 250, Stanford University, Palo Alto, CA 94306.

ACKNOWLEDGEMENTS Work described in this report has been supported in part by the R.S. Kerr Environmental Research Laboratory of the U.S.E.P.A in Ada, Oklahoma, through CR-812462 (Marvin Piwoni, P.O.), by a grant from the Shell Companies Foundation, and by the Deutsche Forschungsgemeinschaft through a scholarship to W. E. The authors thank Dr. Phil Howard, Syracuse Research Corporation, Syracuse, NY for providing a printout of CHEMFATE. This report has not been reviewed by EPA and so does not necessarily reflect the views of EPA, and no official endorsement should be inferred.

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Mabey, W. and T. Mill. 1978. Critical Review of Hydrolysis of Organic Compounds in Water Under Environmental Conditions. J. Phys. Chem. Ref. Data 7:383-415.

2.

Burlinson, N.E., L.A. Lee

and D.H. Rosenblatt. 1982. Kinetics and Products of Hydrolysis of 1,2-

Dibromo-3-chloropropane. Env. Sci. Technol. 16:627-632.

343

3.

Mabey W., V. Barich and T. Mill. 1983. Hydrolysis of Polychlorinated Alkanes. Proceedings, 186th ACSMeeting, Washington DC, August 28 - September 2, pp. 359-361.

4.

Haag W.R., T. Mill and A. Richardson. 1986. Effect of Subsurface Sediment on Hydrolysis Reactions. Proceedings, 192nd ACS-Meeting, Anaheim, CA, September 7-12, pp. 248-253.

5.

Vogel T.M. and

M. Reinhard. 1986. Reaction Products and Rates of Disappearance of Simple

Bromoalkanes, 1,2-Dibromopropane, and 1,2-Dibromoethane in Water. Env. Sci. Technol. 20:992-997. 6.

Callahan M.A., M.W. Slimak, N.W. Gabel, I.P. May, C.F. Fowler, J.R. Freed, P. Jennings, R.L. Durfee, F.C. Whitmore, B. Maestri, W.R. Mabey, B.R. Holt and C. Gould. 1979. Water-Related Environmental Fate of 129 Priority Pollutants Volume II. EPA-440/4-79-029a. U.S. Environmental Protection Agency, Washington, DC.

7.

Howard P.H., G.W. Sage and A. Lamacchia. 1982. The Development of an Environmental Fate Data Base. J. Chem. Inf. Comput. Sci. 22:38-44.

8.

Lyman W.J., W.F. Reehl and D.H. Rosenblatt. 1982. Handbook of Chemical Property Estimation Handbook, McGraw-Hill, New York, NY, pp. 7.1-7.48.

9.

Neely W.B. 1985. Hydrolysis. In W.B. Neely and G.E. Blau, eds., Environmental Exposure from Chemicals, Vol I. CRC Press, Boca Raton, FI, pp. 157-173.

10.

March J. 1985. Advanced Organic Chemistry, Reactions, Mechanisms and Structure. Wiley, New York, NY.

11.

Carey F.A. and R.J. Sundberg. 1984. Advanced Organic Chemistry, 2nd ed., Part A. Plenum Press, New York, NY.

12.

Walraevens R., P. Trouillet and A. Devos. 1974. Basic Elimination of HC1 from Chlorinated Ethanes. Int. J. Chem. Kinetics 7:777-786.

13.

Vogel T.M., C.S. Criddle and P.L. McCarty. 1987. Transformations of halogenated aliphatic compounds. Env. Sci. Technol. 21:722-736.

14.

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(Received in Germany 21 October 1987; accepted ii November 1987)