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Author Washington, J. W.
Sponsorship USDOE
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ENVIRONMENTAL SCIENCES ♦ ORGANIC COMPOUNDS ♦ HYDROLYSIS ♦ AQUIFERS ♦ REMEDIAL ACTION ♦ GROUND WATER ♦ WATER POLLUTION ♦ CHLORINATED ALIPHATIC HYDROCARBONS ♦ WATER CHEMISTRY ♦ TEMPERATURE DEPENDENCE ♦ BROMINATED ALIPHATIC HYDROCARBONS
Abstract Arrhenius parameters, 25 and 10 C rate constants for hydrolysis of most EPA 601/602 volatile organic compounds (VOCs), their hydrolytic progeny, and selected other VOCs are tabulated. Data include Arrhenius parameters for base-mediated hydrolysis of bromodichloromethane, bromoform, dibromochloromethane, and the acid-mediated hydrolysis of ethylene oxide which have not been published before. The average activation energy of the tabulated values, excepting epoxides, is 110, 100 joules per mole, which exceeds values reported previously as typical for VOCs. As a result of this high activation energy, the half-lives of VOCs typically are more than an order of magnitude longer at 10 than 25 C. These data are necessary for calculating hydrolysis rates accurately and, thus, for estimating remediation effectiveness when hydrolysis is being considered for remediation. Other things being equal, hydrolysis rates become much faster with increasing temperature and, for some VOCs, with increasing pH. The hydrolysis half-lives at 25 C and pH = 7 of many haloalkanes and halogenated alcohols are less than 100 years, many halomethanes, and halogenated aldehydes are less than 1,000 yr, and many haloalkenes and aromatic VOCs tend to exceed 1,000 yr. These data can be used to select temperature and pH conditions to impose on water to favor fast hydrolysis or, for branching degradation schemes, select the shorter lived or less toxic progeny. Moreover, these data are necessary to calculate the major hydrolysis progeny for any conditions. Also, these data can be used in forensic geochemical applications such as estimating original contamination composition, time since contamination occurred, distance to source, and whether nonaqueous-phase liquids persist. The main base-mediated hydrolytic degradation route of haloalkanes is induced to be dehydrohalogenation and the main progeny of these reactions are ethenes.
ISSN 0017467X
Educational Use Research
Learning Resource Type Article
Publisher Date 1995-05-01
Publisher Place United States
Journal Ground Water
Volume Number 33
Issue Number 3


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