756-80-9

Basic information

• Product Name: Dimethylphosphorodithioate
• Synonyms: dimethyldithio;dimethyldithiophosphate;dimethylphosphodithionate;kwasdwumetylo-dwutiofosforowy;kyselinao,o-dimethyldithiofosforcna;METHOTHIOACID;AURORA KA-1662;DMPTA
• CAS NO: 756-80-9
• Molecular Formula: C₂H₇O₂PS₂
• Molecular Weight: 158.18
• EINECS: 212-053-9
• Mol File: 756-80-9.mol

Chemical Properties

• Boiling Point: 65℃
• Flash Point: 71.2oC
• Appearance: /
• Density: 1.29
• Vapor Pressure: 0.627mmHg at 25°C
• Refractive Index: 1.535
• Storage Temp.: -20°C
• PKA: -0.10±0.30(Predicted)
• Water Solubility: 226g/L at 20℃
• CAS DataBase Reference: Dimethylphosphorodithioate(CAS DataBase Reference)
• NIST Chemistry Reference: Dimethylphosphorodithioate(756-80-9)
• EPA Substance Registry System: Dimethylphosphorodithioate(756-80-9)

Safety Data

• Hazardous Substances Data: 756-80-9(Hazardous Substances Data)

Usage

Uses

Used in Pesticide Industry:
Dimethylphosphorodithioate is used as a pesticide intermediate for the preparation of organophosphorus pesticides such as dimethoate and malathion. It plays a crucial role in the development of these pesticides, which are widely used in agriculture to protect crops from pests and ensure a stable food supply. Dimethylphosphorodithioate's chemical properties make it an effective building block for creating potent and widely used pesticides.

Flammability and Explosibility

Flammable

InChI:InChI=1/C2H7O2PS2/c1-3-5(6,7)4-2/h1-2H3,(H,6,7)/p-1

Synthetic route

methanol (67-56-1) → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With pyridine; dmap; tetraphosphorus decasulfide; dimethylsulfide at 25 - 55℃; under 40 Torr; for 1h; Pressure; Temperature; Large scale;	97%
With tetraphosphorus decasulfide In chloroform for 10h; Heating;	88%
With tetraphosphorus decasulfide In toluene at 40℃; for 11.5h; Reflux; Inert atmosphere;	86%

ammonium O,O-dimethyl dithiophosphate → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
	96.8%

dimethyl S-methyl phosphorodithioate (2953-29-9) + isopropyl alcohol (67-63-0) → dimethyl thiophosphite (5930-72-3) + thiophosphoric acid O-isopropyl ester O',O''-dimethyl ester (75511-31-8) + thiophosphoric acid O-isopropyl ester O',S-dimethyl ester (75511-33-0) + O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
In acetonitrile Product distribution; Mechanism; Quantum yield; Irradiation; var. of solvent, conc., competition with MeOH, further with triplet sensitizers;	A n/a B 66% C 19% D n/a

dimethyl S-methyl phosphorodithioate (2953-29-9) → O,O-dimethyl phosphorodithioic acid (756-80-9)

[(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester (121-75-5) + water (7732-18-5) + acetone (67-64-1) → diethylmalate (7554-12-3) + O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
at 0 - 30℃; Rate constant; pH 9 bis pH 11.Hydrolysis;

methyl iodide (74-88-4) → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With sodium hydroxide; dithioorthophosphoric acid; tetraethylammonium iodide In dichloromethane at 20℃; for 0.5h;

S-2-ethylthioethyl O,O-dimethyl phosphorodithioate (640-15-3) + thiophenolate (13133-62-5) → (2-ethylsulfanyl-ethylsulfanyl)-benzene + dithiophosphoric acid S-(2-ethylsulfanyl-ethyl) ester O-methyl ester + methyl-phenyl-thioether (100-68-5) + O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With tetraborate buffer; sodium chloride In methanol at 25℃; pH=9.20; Kinetics; Further Variations:; Temperatures;

S-2-ethylthioethyl O,O-dimethyl phosphorodithioate (640-15-3) → dimethylthiophosphoric acid (1112-38-5) + 2-(ethylsulfanyl)ethanol (110-77-0) + 2-ethylsulfanyl-ethanethiol (26750-44-7) + O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With tetraborate buffer; sodium chloride In methanol at 25℃; pH=9.20; Kinetics; Further Variations:; Temperatures; Reagents;

methanol (67-56-1) + tetraphosphorus decasulfide (15857-57-5) → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
In methanol react. of methanol with P4S10;;

O,O'-Dimethyldithiophosphoric acid ammonium salt (1066-97-3) → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With sulfuric acid In dichloromethane at -25 - 25℃; pH=< 2.0;

[(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester (121-75-5) → O,O-dimethyl phosphorodithioic acid (756-80-9)

Conditions	Yield
With 1-butyl-3-methylimidazolium alanine acid salt In acetonitrile at 25℃; Kinetics; Microwave irradiation; Green chemistry;

mesoxalodinitrile 2-chlorophenylhydrazone (55653-03-7) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {[(2-chloro-phenyl)-hydrazono]-cyano-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

2-[(2-nitrophenyl)hydrazono]malononitrile (55653-13-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {cyano-[(2-nitro-phenyl)-hydrazono]-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

2-[(2,5-Dichloro-phenyl)-hydrazono]-malononitrile (1208-17-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {cyano-[(2,5-dichloro-phenyl)-hydrazono]-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

4-nitrophenylhydrazonopropanedinitrile (3722-12-1) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {cyano-[(4-nitro-phenyl)-hydrazono]-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

O,O-dimethyl phosphorodithioic acid (756-80-9) + 2-phenylhydrazonomalononitrile (306-18-3) → [cyano-(phenyl-hydrazono)-thioacetyl]-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

O,O-dimethyl phosphorodithioic acid (756-80-9) + 2-[(4-chlorophenyl)hydrazono]malononitrile (946-76-9) → {[(4-chloro-phenyl)-hydrazono]-cyano-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

O,O-dimethyl phosphorodithioic acid (756-80-9) + 2-[(2-Methoxy-phenyl)-hydrazono]-malononitrile (1208-10-2) → {cyano-[(2-methoxy-phenyl)-hydrazono]-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	99%

triisopropylgallium (54514-59-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → O,O'-dimethyldithiophosphatodiisopropylgallane

Conditions	Yield
In benzene byproducts: i-propanol; stoich. amt. of org. compd. soln. addn. dropwise to Ga-compd. soln. over5 min, mixt. stirring under light vac. for 12 h, solvent vac. removal,; elem. anal.;	99%

triisopropyl indium (17144-80-8) + O,O-dimethyl phosphorodithioic acid (756-80-9) → O,O'-dimethyldithiophosphatodiisopropylindane

Conditions	Yield
In benzene byproducts: i-propanol; stoich. amt. of org. compd. soln. addn. dropwise to Ga-compd. soln. over5 min, mixt. stirring under light vac. for 12 h, solvent vac. removal,; elem. anal.;	99%

O,O-dimethyl phosphorodithioic acid (756-80-9) + Diethyl maleate (141-05-9) → [(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester (121-75-5)

Conditions	Yield
With hydrogenchloride In water at 10 - 40℃; for 8h; Reagent/catalyst; Green chemistry;	98%
With triethylamine; hydroquinone
With hydroquinone In water at 53℃; for 8h;
at -30 - -25℃; Inert atmosphere;
With triethylamine; hydroquinone

allylisocyanate (1476-23-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → O,O-dimethyl-S-(N-allylcarbamoyl) dithiophosphate

Conditions	Yield
In tetrachloromethane	98%

dodecane+O,O-dimethyl-dithiophosphoric acid + O,O-dimethyl phosphorodithioic acid (756-80-9) + Diethyl maleate (141-05-9) → [(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester (121-75-5)

Conditions	Yield
With sodium hydrogencarbonate In dodecane	98%

Ti(O-t-Am)4 (10585-26-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → bis(tert-amyloxy)bis(O,O'-dimethyl dithiophosphato)titanium(IV)

Conditions	Yield
In dichloromethane byproducts: C2H5C(CH3)2OH; room temp., 4 h (pale yellow soln.); solvent pumped off; elem. anal.;	98%

titanium(IV) isopropylate (546-68-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → diisopropoxybis(O,O'-dimethyl dithiophosphato)titanium(IV)

Conditions	Yield
In dichloromethane byproducts: (CH3)2CHOH; room temp., 4 h (pale yellow soln.); solvent pumped off; elem. anal.;	98%

2-[(3-methoxyphenyl)-hydrazono]malononitrile (1208-93-1) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {cyano-[(3-methoxy-phenyl)-hydrazono]-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	97%

diphenylguanidine (102-06-7) + O,O-dimethyl phosphorodithioic acid (756-80-9) → N,N'-Diphenyl-guanidine; compound with dithiophosphoric acid O,O'-dimethyl ester (135672-74-1)

Conditions	Yield
In chloroform for 0.25h; Ambient temperature; other diorganyldithiophosphoric acids;	96%
In chloroform for 0.25h; Ambient temperature;	96%

carbonyl cyanide m-chlorophenylhydrazone (555-60-2) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {[(3-chloro-phenyl)-hydrazono]-cyano-thioacetyl}-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	96%

Propargylic aldehyde (624-67-9) + O,O-dimethyl phosphorodithioic acid (756-80-9) → 3-(dimethoxyphosphinothioylthio)acrolein (95601-21-1)

Conditions	Yield
In tetrachloromethane at 25℃; for 16h;	95%

N-(2,2,2-trichloroethylidene)acetamide (26404-44-4) + O,O-dimethyl phosphorodithioic acid (756-80-9) → O,O-dimethyl S-(1-acetamido-2,2,2-trichloroethyl) phosphorodithioate (75320-60-4)

Conditions	Yield
In benzene	95%

hexamethyldisilathiane (3385-94-2) + O,O-dimethyl phosphorodithioic acid (756-80-9) → O,O-dimethyl dithiophosphoric acid S-trimethylsilyl ester (18135-34-7)

Conditions	Yield
at 50℃; for 0.5h;	95%

O,O-dimethyl phosphorodithioic acid (756-80-9) → dimethyl chlorothiophosphate (2524-03-0)

Conditions	Yield
With chlorine; iron In water at 50℃; for 6h;	94.3%
With chlorine at 30 - 40℃; for 3h; Temperature; Green chemistry;	92.1%
With chlorine; benzene
With chlorine In tetrachloromethane at 0℃; Inert atmosphere;
With chlorine; benzene

O,O-dimethyl phosphorodithioic acid (756-80-9) + tin(ll) chloride → C2H7Cl2O3PSSn

Conditions	Yield
In ethanol at 5℃; Inert atmosphere;	93.5%

tris[triphenylphosphinegold(I)]oxonium tetrafluoroborate (53317-87-6) + O,O-dimethyl phosphorodithioic acid (756-80-9) → (CH3O)2P(SAuP(C6H5)3)2(1+)*BF4(1-) = [(CH3O)2P(SAuP(C6H5)3)2](BF4)

Conditions	Yield
With NaBF4 In dichloromethane (N2); excess (EtO)2P(S)SH; stirring (1 h); crystn. (CHCl3, layering with Et2O); elem. anal.;	92%

O,O-dimethyl phosphorodithioic acid (756-80-9) + 2-[2-(2-methylphenyl)hydrazono]malononitrile (55653-08-2) → [cyano-(o-tolyl-hydrazono)-thioacetyl]-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	91%

diallyl(dimethyl)silane (1113-12-8) + O,O-dimethyl phosphorodithioic acid (756-80-9) → me2Si{pr-2-SPS(Ome)2}2

Conditions	Yield
In not given addn. of HSPS(OCH3)2 to a 5-10% excess of (CH3)2Si(CH2CHCH2)2;;	90%

tetramethyl ammoniumhydroxide (75-59-2) + O,O-dimethyl phosphorodithioic acid (756-80-9) → {N(CH3)4}(1+)*{CH3OPOCH3S2}(1-)={N(CH3)4}{CH3OPOCH3S2}

Conditions	Yield
In water; toluene	90%

O,O-dimethyl phosphorodithioic acid (756-80-9) + 2-[2-(3-methylphenyl)hydrazono]malononitrile (3722-14-3) → [cyano-(m-tolyl-hydrazono)-thioacetyl]-thiophosphoramidic acid O,O'-dimethyl ester

Conditions	Yield
With sodium ethanolate In benzene at 20℃; Addition;	90%

Upstream product

• 67-56-1 methanol 
• 2953-29-9 dimethyl S-methyl phosphorodithioate 
• 67-63-0 isopropyl alcohol 
• 121-75-5 [(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester 
• 7732-18-5 water 
• 67-64-1 acetone 
• 74-88-4 methyl iodide 
• 640-15-3 S-2-ethylthioethyl O,O-dimethyl phosphorodithioate 
• 13133-62-5 thiophenolate 
• 15857-57-5 tetraphosphorus decasulfide 
• 1066-97-3 O,O'-Dimethyldithiophosphoric acid ammonium salt 

Downstream Products

• 118019-48-0 disulfidothiophosphoric acid S-S-(2,4-dinitro-phenyl ester)-O,O'-dimethyl ester 
• 3700-89-8 dimethoxythiophosphorylsulfanyl-succinic acid dimethyl ester 
• 109439-89-6 disulfidothiophosphoric acid O,O'-dimethyl ester-S-S-(2-nitro-phenyl ester) 
• 107-56-2 O,O-diisopropyl hydrogen phosphorodithioate 
• 640-15-3 S-2-ethylthioethyl O,O-dimethyl phosphorodithioate 
• 2253-43-2 O_.O-Dipropyl-dithyophosphat 
• 121-75-5 [(dimethoxyphosphinothioyl)thio]-butanedioic acid, diethyl ester 
• 109440-07-5 disulfidothiophosphoric acid O,O'-dimethyl ester-S-S-(4-nitro-phenyl ester) 
• 3700-91-2 dimethoxythiophosphorylsulfanyl-succinic acid dipropyl ester 
• 3700-90-1 dimethoxythiophosphorylsulfanyl-succinic acid diisopropyl ester 
• 5114-31-8 dithiophosphoric acid S-(4-chloro-phenyl ester)-O,O'-dimethyl ester 
• 117880-74-7 disulfidothiophosphoric acid S-S-(4-chloro-2-nitro-phenyl ester)-O,O'-dimethyl ester 
• 18547-52-9 bis-(2-dimethoxythiophosphorylsulfanyl-propyl)-methyl-phenyl-silane 
• 2524-03-0 dimethyl chlorothiophosphate 

Relevant articles and documents

Kinetic Study of the Homogenous Methanolysis of Tetraphosphorus Decasulphide

The rate of homogenous methanolysis of pure P4S10, dissolved is CS2, has been measured at 0, 15, 25, and 35 deg C for various MeOH:P4S10 molar ratios.The sole product detected was (MeO)2PS2H.At not too low concentrations, the reaction is virtually first order in and second order in , owing probably to an autocatalytic process.The multistep reaction is kinetically controlled by the initial attack on P4S10; this is tentatively explainedby the rigidity and geometry of the P4S10 molecule and/or by the spontaneous formation of reactive dithioxophosphoranes ZP(=S)2 P(S)S-> from all alcoholysis intermediates.Calculaed activation parameters are discussed.Novel data on the solubility of P4S10 are reported.

Malathion hapten, artificial antigen and preparation method thereof (by machine translation)

The synthetic steps of the invention, are simple and convenient, raw materials are easily available (I), the reaction conditions are mild, and the preparation method of the malathion hapten n＝1-9. can be applied to a rapid detection method for establishment of malathion and a detection requirement, for developing the malathion residues; of the malathion artificial antigen, are shown, through, of the present invention can induce the production, of malathion phosphorus as a starting material, and the preparation method of the human immunogen immunized animal, can be applied to laboratory and factory production . The invention, discloses a method, for rapidly detecting malathion and a, preparation method of the artificial antigen. (by machine translation)

Microwave-assisted nucleophilic degradation of organophosphorus pesticides in propylene carbonate

Propylene carbonate is becoming a suitable green alternative to volatile organic solvents in the study of chemical reactions. In this study, an efficient method for nucleophilic degradation of five organophosphorus pesticides, fenitrothion, malathion, diazinon, parathion, and paraoxon, using propylene carbonate as a solvent is proposed. The effect of changing the nature of the nucleophile and the influence of microwave (MW) heating were investigated. A screening of temperatures (50 °C-120 °C) was performed under microwave heating. The pesticide degradation was followed by 31P NMR, and the extent of conversion (%) was calculated by the integration of phosphorus signals. Keeping in mind that recently it has been reported that some ionic liquids play a nucleophilic role, in this work we report for the first time the degradation of organophosphorus pesticides by using an amino acid-based ionic liquid such as Bmim[Ala] as a nucleophile and a bio-based solvent (propylene carbonate) as a reaction medium in combination with microwave heating. This journal is

Synthesizing method of O,O-dimethyl phosphorodithioate

The invention belongs to the technical field of chemical synthesis, and particularly relates to a synthesizing method of O,O-dimethyl phosphorodithioate. The synthesizing method of the O,O-dimethyl phosphorodithioate has the advantages that on the basis of existing technical method, a proper catalyst is further screened, added into a methanol solution and dripped into a sulfide mother liquid, so that the content and yield of the target product are further increased; the whole methanol dripping process is performed under the micro-negative pressure condition, so that the step of dripping the methanol to react can be performed at lower temperature of 25 to 35 DEG C, and the reaction product of hydrogen sulfide can escape out at micro-negative pressure of 30 to 50mmHg, so as to effectively accelerate the reaction to perform along the positive direction.

Z-Selective ring opening of vinyl oxetanes with dialkyl dithiophosphate nucleophiles

Dialkyl dithiophosphates selectively ring open vinyl oxetanes in excellent yields under mild reaction conditions to form useful allylic thiophosphate products with high Z-selectivity. The Royal Society of Chemistry 2013.

Dialkyl (alkylene) dithiophosphate adducts of anhydrous stannous chloride: Synthesis, characterization, and biological activities

Dialkyl (alkylene) dithiophosphate adducts of stannous chloride were synthesized by the reaction of anhydrous tin(II) chloride (SnCl2) and dialkyl (alkylene) dithiophosphoric acid in a 1:1 molar ratio, under anhydrous reaction conditions, below 5 °C in a closed vessel. The newly synthesized adducts were characterized by physicochemical and spectroscopic techniques [FT-IR, NMR (1H, 31P, and 119Sn), and mass spectrometry]. Coordination modalities have indicated a donor-acceptor interaction between sulfur and tin(II) moieties, where tin(II) acts as a Lewis acid. The adducts were found to have significant antibacterial activity against Escherichia coli and Pseudomonas aeruginosa, and antifungal activity against Aspergillus niger and Candida albicans. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

PROCESS FOR THE PREPARATION OF MALATHION AND ITS INTERMEDIATE

The present invention relates to the improved process for the preparation of highly pure form of S-[1,2-(dicarbethoxy)-ethyl]O,O-dimethyl phosphorodithioate having formula (I). The compound of formula (I) has adopted name "Malathion". The present invention also relates to the novel process of preparing intermediate O,O- dimethyldithiophosphoric acid of formula (II), which is useful in the preparation of Malathion. The Malathion prepared by the process of this invention is highly storage stable and toxic impurities are much lower than any other commercial preparation available for the pharmaceutical purpose.

An efficient synthesis of O,O- di propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) oxime and its analogues: A potential marine toxin

An efficient method for the synthesis of Ptychodiscus brevis toxin O,O- di n-propyl (E)-2-[1-methyl 2-oxopropylidene]phosphorohydrazidothiolate (E) oxime (TG-1) and its analogues has been developed using thermally stable and recyclable silica gel and Na2SO4 as a condensing agent and water scavenger, respectively. The compounds were evaluated against fish Rasbora daniconius by determining the LC50 and LC90 values. The results of biological evaluation showed that these compounds have high degree of toxicity. Copyright Taylor & Francis Group, LLC.

Process for Preparing Malathion for Pharmaceutical Use

The present invention provides a process for preparing a highly pure form of malathion having a reduced level of toxic impurities. In addition, the malathion prepared by the process of this invention is storage stable. The level of toxic impurities in the malathion, e.g., isomalathion, O,O,S-trimethyl phosphorodithioate (MeOOSPS), O,O,S-trimethyl phosphorothioate (MeOOSPO), O,S,S-trimethyl phosphorodithioate (MeOSSPO), malaoxon, isomalathion, diethyl fumarate, methyl malathion, dimethyl malathion, O,O-methyl,ethyl-S-(1,2-dicarboethoxy)ethyl-phosphorodithioate are lower than that of any other commercial preparation of malathion that may be used for pharmaceutical purposes.

Reaction of thiometon and disulfoton with reduced sulfur species in simulated natural environment

The reactions of thiometon and its ethyl analogue, disulfoton, with reduced sulfur species [e.g., bisulfide (HS-), polysulfide (S n2-), thiophenolate (PhS-), and thiosulfate (S2O32-)] were examined in well-defined aqueous solutions under anoxic conditions. The role of reduced sulfur species was investigated in the abiotic degradation of thiometon and disulfoton. Experiments at 25°C demonstrated that HS-, Sn2-, PhS-, and S2O32- promoted the degradation of thiometon to a great extent while only Sn2- and PhS- showed a small accelerating effect in the degradation of disulfoton. Reactions were monitored at varying concentrations of reduced sulfur species to obtain the second-order rate constants. The reactivity of the reduced sulfur species decreased in the following order: Sn 2- > PhS- > HS- ≈ S2O 32-. Transformation products were confirmed by standards or characterized by gas chromatography mass spectrometry. The results illustrate that multiple pathways occur in the reactions with reduced sulfur species, among which the nucleophilic attack at the α-carbon of the alkoxy group was the predominant pathway. Activation parameters of the reaction of thiometon and disulfoton with HS- were also determined from the measured second-order rate constants over a temperature range. ΔH≠ values indicated that the reactivity of thiometon toward HS- was much greater than for disulfoton. Nucleophilic attack at the alkoxy group was more important for thiometon than disulfoton. When the measured second-order rate constants at 25°C are multiplied by [HS-] and ∑[S n2-] reported in saltmarsh porewaters, predicted half-lives show that reduced sulfur species present at environmentally relevant concentrations may present an important sink for thiometon in coastal marine environments.