Registration Dossier

Environmental fate & pathways

Hydrolysis

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Administrative data

Endpoint:
hydrolysis
Type of information:
other: handbook
Adequacy of study:
supporting study
Study period:
1993
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data

Data source

Reference
Reference Type:
publication
Title:
Environmental fate constants for organic chemicals under consideration for EPA's hazardous waste identification projects
Author:
Kollig, HP et al.
Year:
1993
Bibliographic source:
EPA/600/R-93/132

Materials and methods

Principles of method if other than guideline:
Assessment of a potential risk posed to humans by man-made chemicals in the environment requires the prediction of environmental concentrations of those chemicals under various environmental reaction conditions. Whether mathematical models or other assessment techniques are employed, knowledge of equilibrium and kinetic constants (fate constants) is required to predict the transport and transformation of these chemicals.
In May 20, 1992, Federal Register, EPA proposed two approaches for amending its regulations under Resource Conservation and Recovery Act (RCRA) for hazardous waste identification. The proposed rule is called the Hazardous Waste Identification Rule (HWIR). The first proposed approach established Concentration-Based Exemption Criteria (CBEC) for listed hazardous wastes, waste mixtures, derivatives, and media (including soils and ground-water) contaminated with certain listed hazardous wastes for exiting RCRA Subtitle C management requirements. The second proposed approach is referred to as the Expanded CHaracteristics Option (ECHO). It established "characteristic" levels for listed hazardous wastes, waste mixtures, derivatives, and media (including soils and ground-water) contaminated with certain listed hazardous wastes for both entering and exiting RCRA Subtitle C via an expansion of the number of toxic constituents in the Toxicity Characteristics (TC) rule.
The purpose of this rulemaking was to take an initial step towards defining wastes that do not merit regulation under Subtitle C and that can and will be safely managed under other regulatory regimes. For establishing exemption criteria, the Agency selected 200 chemical constituents. For all organic compounds on the HWIR list, EPA’s Office of Solid Waste (OSW) requested that the Environmental Research Laboratory-Athens (ERL-Athens):
a) identify those that do not hydrolyse.
b) identify those that do hydrolyse and list the products of degradation including hydrolysis rate constants for parents and intermediates obtained either through laboratory experiments, literature searches, or pathway analyses.
c) obtain sorption data as the organic-carbon-normalized sediment-water partition coefficient either through laboratory experiments, literature searches, or computational techniques.
d) to the extent that current scientific knowledge will permit, identify those that will be subject to other important degradation reactions and identify products of these reactions including rate constants.
For compounds identified as having no hydrolysable functional group (NHFG), hydrolysis will not occur by abiotic reaction pathways in the pH range of 5 to 9 at 25 °C. The compounds identified as having non-labile functional groups (NLFG) will not hydrolyse to any reasonable extent. Although a molecule with a non-labile functional group contains one or more heteroatoms, they react so slowly over the pH range of 5 to 9 at 25 °C, that their half-lives are greater than 50 years, if they react at all.
GLP compliance:
no

Test material

Radiolabelling:
no
Remarks:
not applicable, theoretical evaluation only

Study design

Analytical monitoring:
no
Remarks:
not applicable, theoretical evaluation only
Positive controls:
no
Negative controls:
no

Results and discussion

Transformation products:
not measured
Dissipation DT50 of parent compound
Remarks on result:
not measured/tested
Remarks:
not applicable, theoretical evaluation only
Details on results:
Selected groups of chemicals and their ability to hydrolyse:

Halogenated Aliphatics

Simple halogenated aliphatics
Hydrolysis of the simple halogenated aliphatics (halogen substitution at one carbon atom) is generally pH independent, resulting in the formation of alcohols by nucleophilic substitution with water. Under environmental conditions the most comment hydrolysis process for halogenated aliphatics is the nucleophilic substitution. Although a number of the simple halogenated aliphatics are susceptible to base-mediated hydrolysis, this method of substitution doesn’t contribute to the overall hydrolysis rate under environmental conditions.
The halogenated methanes, except for the trihalomethanes (i.e. chloroform), hydrolyse by direct nucleophilic displacement by water (SN2 mechanism). An increase in the number of halogen substituents on carbon increases the hydrolysis half-life because of the greater steric bulk about the site of nucleophilic attack. The type of halogen substituent also affects reactivity. For example, hydrolysis data indicate that the stability in water decreases in order from fluorinated aliphatics through chlorinated aliphatics to brominated aliphatics (F > CI > Br).
In contrast to the halogenated methanes which have hydrolysis half-lives on the order of years, the hydrolysis half-lives for allylic and benzylic halides are on the order of minutes to hours. The hydrolysis of these chemicals occurs through an indirect nucleophilic displacement by water (SN1 mechanism). The dramatic increase in reactivity is due to the structural features of these compounds that allow for delocalisation, and thus, stabilisation, of the carbonium ion intermediate.

Polyhalogenated aliphatics
For the polyhalogenated ethanes and propanes in addition to the nucleophilic substitution reactions, degradation of these compounds can occur through the base-mediated loss of HX. Depending on structure type, elimination or dehydrohalogenation may be the dominant reaction pathway at environmentally relevant pHs. This process often results in the formation of halogenated alkenes, which can be more persistent and of more concern than substitution products. For a number of the polyhalogenated aliphatics, both neutral and base-mediated hydrolysis will occur at ambient environmental pH and that the relative contributions of these processes will be dependent on the degree and pattern of halogen substitution. The rates of dehydrohalogenation reactions will be dependent on the strength of the C-X bond being broken in the elimination process. Accordingly, it is expected that the ease of elimination of X will follow the series Br > Cl > F.

Epoxides
The hydrolysis of epoxides is pH dependent and can occur through acid-, neutral-, or base-promoted processes. Because the acid and neutral processes dominate over ambient environmental pH ranges, the base-mediated process can often be ignored. The products resulting from the hydrolysis of epoxides are diols, and to a lesser extent, rearrangement products.

Organophosphorus Esters
Mechanistic studies of organophosphorus esters have demonstrated that hydrolysis occurs through direct nucleophilic displacement at the central phosphorus atom and does not involve formation of a pentavalent intermediate with H2O or HO-. Accordingly, hydrolysis rates for phosphorus esters will be sensitive to electronic factors that alter the electrophilicity of the central phosphorus atom and steric interactions that impede nucleophilic attack. An interesting feature of the hydrolytic degradation of phosphorus esters is that carbon-oxygen or carbon-sulfur cleavage may also occur. It is generally observed that base-mediated hydrolysis favors P-O cleavage, and that neutral and acid catalysis favors C-O or C-S cleavage. As a result, hydrolysis mechanisms and product distribution for the organophosphorus esters will be pH dependent.

Carboxylic Acid Esters
Hydrolysis of carboxylic acid esters results in the formation of a carboxylic acid and an alcohol. The two most common mechanisms for hydrolysis are involving acyl-oxygen bond cleavage by acid catalysis (AAC2) and base mediation (BAC2). Hydrolysis via the AAC2 mechanism involves initial protonation of the carbonyl oxygen. Protonation polarises the carbonyl group, removing electron density from the carbon atom and making it more electrophilic and thus more susceptible to nucleophilic addition by water. The base-mediated mechanism (BAC2) proceeds via the direct nucleophilic addition of HO- to the carbonyl group. Base mediation occurs because the hydroxide ion is a stronger nucleophile than water. Although neutral hydrolysis of carboxylic acid esters does occur, the base-mediated reaction will be the dominant pathway in most natural waters. Generally, acid hydrolysis will dominate in acidic waters with pH values below 4.

Amides
Hydrolytic degradation of amides results in the formation of a carboxylic acid and an amine. In general, amides are much less reactive towards hydrolysis than esters. Typically, half-lives for amides at ambient environmental conditions are measured in hundreds to thousands of years. This observation can be explained by the ground-state stabilization of the carbonyl group by the electron donating properties of the nitrogen atom. This stabilization is lost in the transition state leading to the formation of the tetrahedral intermediate. The result is that the hydrolysis of amides generally requires base or acid catalysis, both of which can compete at neutral pH.

Carbamates
A carbamate is hydrolysed to an alcohol, carbon dioxide, and an amine. Carbamates are susceptible to acid, neutral and base hydrolysis, although at environmental conditions base hydrolysis will dominate. Carbamates hydrolyse in an analogous manner to carboxylic acid ester and amide hydrolysis.

Nitriles
Nitriles are hydrolysed to give a carboxylic acid and ammonium ion. Hydrolysis occurs through the intermediate amide. Base-mediated hydrolysis appears to be the dominant hydrolysis pathway at pH 7.

Any other information on results incl. tables

 

No.

Substance

Hydrolyses?

Notes

1

Acenaphthene

No

Does not hydrolyse – no hydrolysable functional group present.

2

Acetone

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

3

Acetonitrile

No

Resistant to hydrolysis. Hydroxide or hydronium is required to facilitate hydrolysis. Hydrolysis proceeds through the intermediate amide to the final product, acetic acid.

4

Acetophenone

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

5

Acrolein

Yes

Undergoes a rapid addition of water across the double bond (Michael addition) to yield 3-hydroxy-1-propanal.

6

Acrylamide

Yes

An intermediate in the hydrolysis of acrylonitrile to acrylic acid. At high concentrations of hydroxide, acrylamide polymerizes. The end product of hydrolysis is acrylic acid.

7

Acrylonitrile

Yes

Hydrolyses to acrylic acid through the intermediate acrylamide.

8

Aldrin

No

All aldrin chlorine atoms are either protected from nucleophilic attack (bridgehead carbon) or are non-reactive (on the sp2 carbon). Aldrin has been designated the assignment of NLFG.

9

Aniline

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

11

Aramite

Yes

The sulfite bond in Aramite is very susceptible to hydrolysis. Initial hydrolysis of Aramite proceeds with cleavage of either of two sulfoxide bonds. This initial hydrolysis yields four products, two alcohols and two hydrogen sulfites.

14

Benz[a]anthracene

No

Does not hydrolyse – no hydrolysable functional group present.

15

Benzene

No

Does not hydrolyse – no hydrolysable functional group present.

16

Benzidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

17

Benzo[b]fluoranthene

No

Does not hydrolyse – no hydrolysable functional group present.

18

Benzo[a]pyrene

No

Does not hydrolyse – no hydrolysable functional group present.

19

Benzotrichloride

Yes

Hydrolysis proceeds through nucleophilic substitution of chlorine by H2O. The halohydrin formed by this displacement is unstable and reacts further to yield benzoic acid.

20

Benzyl alcohol

No

Does not hydrolyse – no hydrolysable functional group present.

21

Benzyl chloride

Yes

Hydrolysis occurs through nucleophilic displacement of chlorine by H2O. Hydrolysis is not mediated by hydroxide.

23

Bis(2-chloroethyl)ether

Yes

Hydrolysis occurs through nucleophilic displacement of chlorine with H2O. The monochloroether formed by this reaction will undergo a second substitution by H2O to yieldbis(2-hydroxyethyl)ether and intramolecular displacement of chlorine to yield dioxane.

24

Bis(2-chloroisopropyl)ether

Yes

Instable with half-life of minutes.

25

Bis(2-ethylhexyl)phthalate

Yes

Hydrolyses by nucleophilic attack of HO-at the ester carbonyl group to give 2-ethylhexyl hydrogen phthalate and 2-ethylhexanol. The monoester will undergo further base-mediated hydrolysis to o-phthalic acid and 2-ethylhexanol.

26

Bromodichloromethane

Yes

Hydrolysis occurs initially by proton abstraction followed by formation of the carbene, which reacts with HO-to form carbon monoxide and the mineral acids.

27

Bromomethane

Yes

Hydrolysis proceeds through nucleophilic substitution of bromine by H2O to yield methanol and hydrobromic acid.

28

Butanol

No

Does not hydrolyse – no hydrolysable functional group present.

29

Butyl benzyl phthalate

Yes

Butyl benzyl phthalate is a mixed ester formed by condensation of phthalic acid with two different alcohols. The hydrolysis mechanism is the same as described forbis(2-ethyl-hexyl)phthalate (No. 25) with the two resulting monoesters undergoing further hydrolysis to o-phthalic acid and the corresponding alcohols.

30

2-sec-Butyl-4,6-dinitrophenol

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

32

Carbon disulfide

Yes

Hydrolysis occurs by nucleophilic attack of HO-. The initial hydrolysis product is carbonyl sulfide, which reacts further with H2O or HO-to give carbon dioxide and hydrogen sulfide.

33

Carbon tetrachloride

Yes

Hydrolysis occurs by reaction with H2O to yield carbon dioxide and the mineral acid.

34

Chlordane

Yes

Hydrolysis proceeds by nucleophilic substitution of chlorine by HO-to give 2,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano-1H-indene, which will not be susceptible to further hydrolysis.

35

p-Chloroaniline

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

36

Chlorobenzene

No

Does not hydrolyze to any reasonable extent; however, it may undergo other abiotic transformation processes.

37

Chlorobenzilate

Yes

Hydrolysis is analogous to the phthalate esters and proceeds through nucleophilic attack of HO-at the ester carbonyl. The resulting acid is stable in the ionic form, but the protonated form that would exist at acidic pH values will decarboxylate with concurrent oxidation to yield carbon dioxide andp,p'-dichlorobenzophenone.

38

2-Chloro-1,3-butadiene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

39

Chlorodibromomethane

Yes

Hydrolysis occurs initially by proton abstraction followed by formation of the carbene, which reacts with HO-to form carbon monoxide and the mineral acids.

40

Chloroform

Yes

Hydrolysis occurs initially by proton abstraction followed by formation of the carbene, which reacts with HO-to form carbon monoxide and the mineral acid.

41

Chloromethane

Not assessed

Chloromethane has a negative boiling point and exists in a gaseous state at room temperature. Its hydrolysis pathway has not been addressed.

42

2-Chlorophenol

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

43

3-Chloropropene

Yes

Neutral hydrolysis occurs through the formation of the allylic carbonium ion, which reacts with H2O to give 3-hydroxypropene and the mineral acid.

45

Chrysene

No

Does not hydrolyse – no hydrolysable functional group present.

47

o-Cresol

No

Does not hydrolyse – no hydrolysable functional group present.

48

m-Cresol

No

Does not hydrolyse – no hydrolysable functional group present.

49

p-Cresol

No

Does not hydrolyse – no hydrolysable functional group present.

50

Cumeme

No

Does not hydrolyse – no hydrolysable functional group present.

51

Cyanide

Yes

Hydrolyses by nucleophilic attack of H2O resulting in carbon dioxide and ammonia.

52

2,4-Dichlorophenoxyacetic acid

No

Does not hydrolyse to any reasonable extent.

53

DDD

Yes

The reaction of DDD occurs by the elimination of chlorine (dehydrochlorination) to give 2,2-bis(4-chlorophenyl)-1-chloroethene (DDMU). This process will occur by reaction with either H2O or HO-.

54

DDE

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

55

p,p'-DDT

Yes

The reaction ofp.p’-DDT occurs in a manner analogous to DDD. The reaction products resulting from dehydrochlorination are DDE and the mineral acid.

56

Diallate

Yes

Hydrolyses by nucleophilic attack of H2O and HO-at the carbonyl group resulting in the formation of diisopropylamine andcis- andtrans-2,3-dichloro-2-propene-1-thiol.

57

Dibenz[a,h]anthracene

No

Does not hydrolyse – no hydrolysable functional group present.

58

1,2-Dibromo-3-chloropropane

Yes

1,2-Dibromo-3-chloropropane is subject to both neutral and base-mediated hydrolysis. Neutral hydrolysis occurs initially by nucleophilic displacement of either chlorine or bromine.

59

Dibromomethane

No (QSAR)

Dibromomethane should not hydrolyse to any reasonable extent. QSAR model computations have indicated that the half-life of this halogenated methane is several thousand years.

60

1,2-Dichlorobenzene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

61

1,4-Dichlorobenzene

No

Does not hydrolyse to any reasonable extent, however, it may undergo other abiotic transformation processes.

62

3,3'-Dichlorobenzidine

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

63

Dichlorodifluoromethane

Not assessed

Dichlorodifluoromethane has a negative boiling point and exists in a gaseous state at room temperature. Its hydrolysis pathway has not been addressed.

64

1,1-Dichloroethane

Yes

The reaction of 1,1-dichloroethane occurs by both nucleophilic substitution and dehydrochlorination. The reaction products resulting from nucleophilic substitution by H2O and HO-are acetaldehyde and HCl, whereas dehydrochlorination gives vinyl chloride and the mineral acid.

65

1,2-Dichloroethane

Yes

The reaction of 1,2-dichloroethane by H2O and HO-occurs by both nucleophilic substitution and dehydrochlorination. Hydrolysis by nucleophilic substitution will lead to the formation of 2-chloroethanol and HCl, whereas dehydrochlorination results in vinyl chloride and the mineral acid. 2-Chloroethanol will react further producing ethylene oxide, which will hydrolyse by reaction with H2O to yield ethylene glycol.

66

1,1-Dichloroethylene

No

Does not hydrolyse to any reasonable extent.

67

cis-1,2-Dichloroethylene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

68

trans-1,2-Dichloroethylene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

69

Dichloromethane

Yes

Hydrolysis of dichloromethane occurs by nucleophilic substitution with H2O (neutral hydrolysis) resulting in the displacement of chlorine with HO-. The resulting chlorohydrin is a transient intermediate that immediately loses chlorine to yield formaldehyde, the final hydrolysis product.

70

2,4-Dichlorophenol

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

71

1,2-Dichloropropane

Yes

The reaction of 1,2-dichloropropane with H2O or HO-will proceed through competing reaction pathways (nucleophilic substitution and dehydrohalogenation). Nucleophilic substitution will occur at the primary carbon resulting in the formation of 2-chloropropanol. This intermediate will degrade by intramolecular nucleophilic displacement of the chlorine atom by the adjacent hydroxyl group resulting in the formation of propylene oxide. Propylene oxide will undergo predominantly neutral hydrolysis to give 1,2-dihydroxypropane. Base-mediated elimination of chlorine will result in the formation of 1-chloro-l-propene, which will be stable to further hydrolysis.

72

1,3-Dichloropropene

Yes

Hydrolysis will occur by reaction with H2O through nucleophilic substitution resulting in the formation of 3-chloro-2-propene-1-ol.

73

Dieldrin

Yes

Hydrolysis will occur through nucleophilic substitution with H2O at the epoxide moiety resulting in the formation of the diol. The diol will be stable to further hydrolysis.

74

Diethyl phthalate

Yes

The base-mediated hydrolysis will initially result in formation of the monoester, which will undergo further hydrolysis to o-phthalic acid. The hydrolysis of the monoester will occur at a rate approximately half that of the parent compound.

75

Diethylstilbestrol

No

Does not hydrolyse – no hydrolysable functional group present.

76

Dimethoate

Yes

Hydrolysis may occur through either reaction with H2O (neutral hydrolysis) or reaction with HO (base-mediated hydrolysis).

77

3,3'-Dimethoxybenzidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

78

7,12-Dimethylbenz[a]anthracene

No

Does not hydrolyse – no hydrolysable functional group present.

79

3,3'-Dimethylbenzidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

80

2,4-Dimethylphenol

No

Does not hydrolyse – no hydrolysable functional group present.

81

Dimethyl phthalate

Yes

Hydrolyses by nucleophilic attack of HO-at the ester carbonyl group resulting in methyl hydrogen phthalate and methanol, which can undergo further base-mediated hydrolysis to o-phthalic acid.

82

1,3-Dinitrobenzene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

83

2,4-Dinitrophenol

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

84

2,4-Dinitrotoluene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

85

2,6-Dinitrotoluene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

86

Di-n-butyl phthalate

Yes

The reaction pathway for the hydrolysis of di-n-butyl phthalate is identical to that described previously for dimethyl phthalate (#81).

87

Di-n-octyl phthalate

Yes

The reaction pathway for the hydrolysis of di-n-octyl phthalate is identical to that described previously for dimethyl phthalate (#81).

88

1,4-Dioxane

No

Does not hydrolyse – no hydrolysable functional group present.

89

2,3,7,8-TCDDioxin

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

90

2,3,7,8-PeCDDioxins

No

Does not hydrolyse to any reasonable extent; however, they may undergo other abiotic transformation processes.

91

2,3,7,8-HxCDPioxins

No

Does not hydrolyse to any reasonable extent; however, they may undergo other abiotic transformation processes.

92

2,3,7,8-HpCDPioxins

No

Does not hydrolyse to any reasonable extent; however, they may undergo other abiotic transformation processes.

93

OCDD

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

94

Diphenylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

95

1,2-Diphenylhydrazine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

96

Disulfoton

Yes

Neutral hydrolysis can occur at two sites resulting in the formation of phosphorus diesters, which will hydrolyse through the phosphate monoester to eventually give phosphoric acid and hydrogen sulfide. As with dimethoate, base-mediated hydrolysis will occur by nucleophilic attack of HO-at the central phosphorus atom resulting in 2-thioethylethylthioether and O,O-diethylphosphorothioic acid, which will hydrolyse further to phosphoric acid and hydrogen sulfide.

97

Endosulfan

Yes

Endosulfan, which is a mixture of thealpha(Endosulfan I) andbeta(Endosulfan II) isomers, will hydrolyse by nucleophilic attack of H2O or HO-at the sulfur atom resulting in the alpha and beta isomers of endosulfan diol. The ratio of thealphato thebetaisomers of endosulfan diol will reflect the ratio of Endosulfan I to Endosulfan II in the parent compound.

98

Endrin

Yes

Hydrolysis will proceed by nucleophilic attack of H2O at the epoxide moiety resulting in the formation of endrin diol, which will be stable to further hydrolysis.

99

Epichlorohydrin

Yes

Hydrolysis will occur initially by attack of H2O at the epoxide moiety resulting in the formation of 1-chloro-2,3-dihydroxypropane. Subsequently, loss of chlorine will occur through the intramolecular attack of HO-on the adjacent carbon to give 1-hydroxy-2,3-propylene oxide, which will undergo further hydrolysis by attack of H2O at the epoxide moiety to give glycerol.

100

2-Ethoxyethanol

No

Does not hydrolyse – no hydrolysable functional group present.

101

Ethyl acetate

Yes

Hydrolysis will occur by acyl-oxygen bond cleavage by H2O and acid catalysis and base mediation resulting in the formation of acetic acid and ethanol.

102

Ethylbenzene

No

Does not hydrolyse – no hydrolysable functional group present.

103

Ethyl ether

No

Does not hydrolyse – no hydrolysable functional group present.

104

Ethyl methacrylate

Yes

Hydrolysis will occur by the base-mediated cleavage of the acyl-oxygen bond resulting in methacrylic acid and ethanol.

105

Ethyl methanesulfonate

Yes

Hydrolysis will occur in a manner analogous to the hydrolysis of carboxylic acid esters. Nucleophilic attack of H2O at the carbon results in the formation of methylsulfonic acid and ethanol.

106

Ethylene dibromide

Yes

The reaction of ethylene dibromide proceeds by either nucleophilic substitution or dehydrohalogenation.

107

Famphur

Yes

The reaction pathways for the hydrolysis of famphur are similar to the organophosphorus esters. Both base and neutral hydrolysis can occur by nucleophilic attack at the phosphorus atom resulting in the formation of phosphorous diesters, which will hydrolyse through the phosphate monoester eventually to result in phosphoric acid and hydrogen sulfide, andp-(N,N-dimethylsulfamoyl)phenol.

108

Fluoranthene

No

Does not hydrolyse – no hydrolysable functional group present.

109

Fluorene

No

Does not hydrolyse – no hydrolysable functional group present.

110

Formic acid

No

Does not hydrolyse – no hydrolysable functional group present.

111

Furan

No

Does not hydrolyse – no hydrolysable functional group present.

112

2,3,7,8-TCDFuran

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

113

1,2,3,7,8-PeCDFuran

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

114

2,3,4,7,8-PeCDFuran

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

115

2,3,7,8-HxCDFurans

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

116

2,3,7,8-HpCDFurans

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

117

OCDF

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

118

Heptachlor

Yes

Hydrolysis will occur by nucleophilic substitution of H2O at the allylic-carbon-bearing chlorine resulting in the formation of 1-hydroxychlordene, which will be stable to further hydrolysis.

119

Heptachlor epoxide

Yes

Heptachlor will hydrolyse by nucleophilic attack of H2O at the epoxide moiety resulting in heptachlor diol. Further hydrolysis of the diol can occur by nucleophilic substitution of H2O at the chlorine-bearing carbon adjacent to the hydroxyl groups. The resulting triol will be stable to further hydrolysis.

120

Hexachlorobenzene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

121

Hexachlorobutadiene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

122

alpha-HCH

Yes

The reaction ofalpha-HCH occurs bytrans-dehydrochlorination of the axial chlorines resulting in the intermediate 1,3,4,5,6-pentachlorocyclohexene. This cylcohexene will react further with either H2O or HO-through sequential dehydrochlorination steps to give a mixture of the regioisomers, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene.

123

beta-HCH

No

Does not hydrolyse to any reasonable extent (NLFG). The six equatorial chlorines do not permit initial trans-dehydrochlorination to yield the intermediate pentachlorocyclohexene as occurs in thealpha- (#122.) andgamma-isomers (#132).

124

Hexachlorocyclopentadiene

Yes

Hydrolysis results in the formation of 1,1-dihydroxy-tetrachlorocylcopentadiene, which is an unstable product. Its degradation leads to the formation of polymers.

125

Hexachloroethane

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

126

Hexachlorophene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

127

lndeno[1,2,3-cd]pyrene

No

Does not hydrolyse – no hydrolysable functional group present.

128

Isobutyl alcohol

No

Does not hydrolyse – no hydrolysable functional group present.

129

Isophorone

No

Does not hydrolyse – no hydrolysable functional group present.

130

Kepone

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

132

gamma-HCH

Yes

The reaction pathway for the hydrolysis ofgamma-HCH (lindane) is identical to that described foralpha-HCH (#122).

134

Methacrylonitrile

Yes

Hydrolysis will occur by the acid-catalysed or base-mediated hydrolysis of the nitrile moiety to give methacrylic acid and ammonia.

135

Methanol

No

Does not hydrolyse – no hydrolysable functional group present.

136

Methoxychlor

Yes

The products formed during aqueous hydrolysis of methoxychlor are influenced by the pH of the system. Above pH 10, 2,2-bis(p-methoxyphenyl)-1-1-dichloroethylene (DMDE) is the only reported product. Below pH 10 a second product, anisoin, is observed. Anisoin is the major product formed by hydrolysis when the system is below pH 8; however, it is unstable and will oxidize to anisil. Hydrolysis is not an important pathway in further degradation of DMDE and anisil.

137

3-Methylcholanthrene

No

Does not hydrolyse – no hydrolysable functional group present.

138

Methyl ethyl ketone

No

Does not hydrolyse – no hydrolysable functional group present.

139

Methyl isobutyl ketone

No

Does not hydrolyse – no hydrolysable functional group present.

140

Methyl methacrylate

Yes

Hydrolysis proceeds through nucleophilic attack by HO-at the ester carbonyl to yield methacrylic acid and methanol.

141

Methyl parathion

Yes

Hydrolysis may occur through either reaction with H2O (neutral hydrolysis) or reaction with HO-(base-mediated hydrolysis). Nucleophilic substitution by H2O occurs in sequence at the two methoxy carbons to yield O-methyl-O-(p-nitrophenyl)-phosphorothioic acid (diester) and O-(p-nitrophenyl)phosphorothioic acid (monoester), respectively. Hydroxide-ion-mediated hydrolysis of methyl parathion proceeds through initial attack of the hydroxide ion on the phosphorus atom with displacement of the p-nitrophenylate ion. The phosphorothioic acid generated in each hydrolytic pathway will eventually degrade to phosphoric acid and hydrogen sulfide.

142

Naphthalene

No

Does not hydrolyse – no hydrolysable functional group present.

143

2-Naphthylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

145

Nitrobenzene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

146

2-Nitropropane

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

147

N-Nitroso-di-n-butylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

148

N-Nitrosodiethylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

149

N-Nitrosodimethylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

150

N-Nitrosodiphenylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

151

N-Nitroso-di-n-propylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

152

N-Nitrosomethylethylamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

153

N-Nitrosopiperidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

154

N-Nitrosopyrrolidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

155

Octamethyl pyrophosphoramide (OMPP)

Yes

Hydrolysis proceeds through cleavage of the P-O-P bond. OMPP is stable to attack by the hydroxide ion and the neutral water molecule, but is degraded under acidic conditions.

156

Parathion

Yes

Parathion is the ethyl analog of methyl parathion. The products formed and mechanisms of hydrolysis parallel those of methyl parathion (#141) but hydrolysis proceeds at a slower rate typical for triethyl phosphates compared to trimethyl phosphates.

157

Pentachlorobenzene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

158

Pentachloronitrobenzene (PCNB)

No

In an experiment, no disappearance of PCNB was observed after 33 days at pH 11 and 85 °C. PCNB has, therefore, been designated as NLFG.

159

Pentachlorophenol

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

160

Phenol

No

Does not hydrolyse – no hydrolysable functional group present.

161

Phenylenediamine

No

The three isomers don’t hydrolyse; however, it may undergo other abiotic transformation processes.

162

Phorate

Yes

Phorate is an analog of disulfoton. The products formed and mechanisms of hydrolysis parallel those of disulfoton. Phorate has a neutral hydrolysis rate of approximately 30 times that of disulfoton (#96).

163

Phthalic anhydride

Yes

Hydrolyses to o-phthalic acid in water. The hydrolysis occurs through nucleophilic attack of H2O at a carbonyl carbon.

164

Polychlorinated biphenyls

No

Does not hydrolyse to any reasonable extent.

165

Pronamide

No

TheN-substituted amide bond in pronamide, formed by reaction of a carboxylic acid and primary amine, is more resistant to hydrolysis than similar bonds formed with carboxylic acids and alcohols.

166

Pyrene

No

Does not hydrolyse – no hydrolysable functional group present.

167

Pyridine

No

Does not hydrolyse – no hydrolysable functional group present.

168

Safrole

No

Does not hydrolyse – no hydrolysable functional group present.

171

Strychnine

No

Does not hydrolyse to any reasonable extent.

172

Styrene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

173

1,2,4,5-Tetrachlorobenzene

No

Does not hydrolyse to any reasonable extent.

174

1,1,1,2-Tetrachloroethane

Yes

The hydrolysis pathway will proceed through competing pathways (nucleophilic substitution and dehydrohalogenation). Nucleophilic substitution will occur at the monochlorinated carbon with formation of trichloroethanol. Degradation of trichloroethanol will continue to yield glycolic acid (hydroxyacetic acid). Base-mediated elimination of chlorine from 1,1,1,2-tetrachloroethane will result in formation of 1,1,2-trichloroethylene.

175

1,1,2,2-Tetrachloroethane

Yes

Hydrolyses by the base-mediated elimination of chlorine to 1,1,2-trichloroethylene. This quantitative conversion occurs in the pH range of 5-9.

176

Tetrachloroethylene

No

Does not hydrolyse to any reasonable extent.

177

2,3,4,6-Tetrachlorophenol

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

178

Tetraethyl dithiopyrophosphate

Yes

The P-O-P bond is very labile to attack by hydroxide, even at concentrations of hydroxide present below pH 7. The resultingO,O-diethyl-phosphorothioic acid is hydrolysed to the final products phosphoric acid and ethanol.

180

Toluene

No

Does not hydrolyse – no hydrolysable functional group present.

181

2,4-Toluenediamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

182

2,6-Toluenediamine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

183

o-Toluidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

184

p-Toluidine

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

185

Toxaphene

Yes

It is a complex but reproducible mixture of chlorinated camphene (67-69% chlorine by weight). The mixture has been shown to contain at least 177 and up to 670 components. The degradation rate was determined by monitoring the loss of chlorine with time during hydrolysis rate studies.

186

Tribromomethane

Yes

Hydrolysis occurs initially by proton abstraction followed by formation of the carbene, which reacts with HO-to form carbon monoxide and the mineral acid.

187

1,2,4-Trichlorobenzene

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

188

1,1,1-Trichloroethane

Yes

Nucleophilic attack by H2O on the trichloro-substituted carbon yields acetic acid, while the hydroxide-ion-mediated elimination product is 1,1-dichloroethylene. The ratio of these products is pH dependent. Acetic acid is the major product at low values of pH, while the amount of 1,1-dichloroethylene, increases with increasing values of pH.

189

1,1,2-Trichloroethane

Yes

Hydrolysis will yield the substitution product, chloroacetaldehyde, and the base-mediated elimination product, 1,1-dichloroethylene. The most acidic hydrogen (dichloro-substituted carbon) is lost during elimination of chlorine to form 1,1-dichloroethylene rather than 1,2-dichloroethylene. The ratio of products will be determined by the pH of the system.

190

Trichloroethylene

No

Does not hydrolyse to any reasonable extent.

191

Trichlorofluoromethane

No

Does not hydrolyse to any reasonable extent based on other polyhalogenated methanes.

192

2,4,5-Trichlorophenol

No

Does not hydrolyse to any reasonable extent.

193

2,4,6-Trichlorophenol

No

Does not hydrolyse to any reasonable extent.

194

2,4,5-Trichlorophenoxyacetic acid

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

195

2-(2,4,5-Trichloro­phenoxy)propionic acid (Silvex)

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

196

1,2,3-Trichloropropane

Yes

By analogy to 1,2-dibromo-3-chloropropane (#58), the ultimate products of aqueous degradation are 2-chloro-3-hydroxy-1-propene and glycerol. The route to the substitution product, glycerol, proceeds through intermediate haloalcohols and halohydrins. The amount of the elimination product, 2-chloro-3-hydroxy-1-propene, will increase with increase in hydroxide ion concentration.

197

1,1,2-Trichloro-1,2,2-trifluoroethane

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

198

1,3,5-Trinitrobenzene

No

Does not hydrolyse; however, it may undergo other abiotic transformation processes.

199

Tris(2,3-dibromo­propyl)phosphate

Yes

Hydrolysis by nucleophilic attack of H2O on the C-O bond or hydroxide ion attack on phosphorus will yield the same products. The 2,3-dibromo-propanol can undergo hydroxide-ion-mediated elimination to yield 2-bromo-2-propen-1-ol or intramolecular displacement of bromine by the adjacent hydroxyl group to form epibromohydrin. The epibromohydrin is ultimately hydrolysed to the final product, glycerol. TheO,O-(2,3-dibromopropyl)phosphoric acid will hydrolyse further to yield phosphoric acid and 2,3-dibromopropanol.

201

Vinyl chloride

No

Does not hydrolyse to any reasonable extent; however, it may undergo other abiotic transformation processes.

202

Xylenes

No

Does not hydrolyse – no hydrolysable functional group present.

 

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable
Remarks:
theoretical evaluation only
Conclusions:
Under Section 301 of the Resource Conservation and Recovery Act (RCRA), EPA's Office of Solid Waste (OSW) has identified some 200 chemicals to be listed in a proposed rule called the Hazardous Waste Identification Rule (HWIR). This publication addresses the 189 organics listed in the HWIR. The environmental fate constants and the chemical hydrolysis pathways of these chemicals are listed. Chemical hydrolysis rate constants for parent compounds and products including structural presentation of the pathways are presented. A detailed list with all 200 compounds is formed with information if the substance undergoes hydrolysis or not. This list is a great tool to help prediction the hydrolysis properties and pathways of other organics substances containing the same or similar structures like the compounds listed in HWIR.