Monomethyl sulfate

Sulfates having alkyl groups from methyl to pentyl have been examined. With methyl as an example, the hydrolysis rate of dimethyl sulfate iacreases with the concentration of the sulfate. Typical rates ia neutral water are first order and are 1.66 x lO " at 25°C and 6.14 x lO " at 35°C (46,47). Rates with alkaH or acid depend on conditions (42,48). Rates for the monomethyl sulfate [512-42-5] are much slower, and are nearly second order ia base. Values of the rate constant ia dilute solution are 6.5 X 10 L/(mol-s) at 100°C and 4.64 X 10 L/(mol-s) at 138°C (44). At 138°C, first-order solvolysis is ca 2% of the total. Hydrolysis of the monoester is markedly promoted by increasing acid strength and it is first order. The rate at 80°C is 3.65 x lO " ... 

The monoalkyl derivatives in salt form appear to have low toxicity. The monomethyl sulfate sodium salt has an approximate oral lethal dose greater than 5000 mg/kg of body weight for rats (129). Monododecyl sulfate sodium salt is widely marketed as a detergent and shampoo ingredient (oral LD q 1268 mg/kg for rats) (126). Both dimethyl sulfate and monomethyl sulfate occur in the environment in coal fly-ash and in airborne particulate matter (130). 

Numbers used in this cycle AG° for hydroxide plus monomethyl sulfate, assumed to be the same as for dimethyl sulfate estimated above AG° for ionization of monomethyl sulfate AG° for tautomerization of the anionic adduct, based on pK values estimated by the method of Branch and Calvin AG° for ionization of the apically protonated adduct, based on a pK estimated by the method of Branch and Calvin.)... 

Then from the free energy change for addition of hydroxide to monomethyl sulfate and the correction from methyl to p-nitrophenyl used above we get AG° = 18kcal/mol for... 

Most of the known salts without fused rings, on the other hand, are very unstable. Unfortunately, no quantitative studies have so far been carried out on the thermodynamic stability of the 1,3-dithiolium ion, and in view of the limited experimental data available it is impossible to draw any definite conclusions regarding the dependence of stability on the nature of the substituents. It is clear, however, that here the nature of the anion is of vital importance thus whereas 4-(p-methoxyphenyl)-isotrithionium iodide is stable, the pbenyl derivative can be isolated only as the monomethyl sulfate. 

During the polymerization of aromatic diacids and diesters with hydrazine in fuming sulfuric acid, aromatic oxadiazole units are formed first which are subsequently methylated by monomethyl sulfate or its homologues (derived from reaction of the diester with H2SO4) forming an aromatic N-methyl oxadiazolium polymer. This polymer is hydrolyzed during the spinning operation to the fiber polymer, i.e., p-/m-phenylene oxadiazole/N-methyl hydrazide copolymer. 

Chemical and Agrochemical Applications Mohsin [263] developed an IC-MS method using thermospray and electrospray interfaces for the analysis of organophosphorus and organosulfur compounds in an insecticide such as monomethyl phosphate, monomethyl sulfate, and dimethyl phosphate. All three compounds were separated on an lonPac ASH anion exchanger using a NaOH/ methanol mixture as an eluent. Mohsin used an Alltech lOOOHP suppressor to convert the eluent to water prior to entering the MS interface. The Alltech lOOOHP suppressor contains two packed-bed suppressor columns. One of the... 

After all the hydrogen peroxide is added, the reaction mixture is allowed to cool to room temperature and is then saturated with sodium chloride, after which it is extracted four times with 100-ml. portions of ether. The combined extracts are dried over sodium sulfate. The ether is removed by distillation on a steam bath, and the residue is then distilled under reduced pressure, Pyrogallol monomethyl ether is collected at 136-138°/22 mm. The yield is 38-44.5 g. (68-80%) of a colorless to light t11ow oil which solidifies on standing (Note 4). 

Pyrogallol monomethyl ether has been prepared by the methylation of pyrogallol with dimethyl sulfate or methyl iodide by the decarboxylation of 2,3-dihj droxy-4-methoxy-benzoic acid and by the methylation of pyrogallol carbonate with diazomethane and subsequent hydrolysis. The method described is taken from the improved procedure of Baker and Savage for the preparation of pyrogallol monomethyl ether from o-vanillin by oxidation with hydrogen peroxide. 

Eatough DJ, VF White, LD Hansen, NL Eatough, JL Cheney (1986) Identification of gas-phase dimethyl sulfate and monomethyl hydrogen sulfate in the Los Angeles atmosphere. Environ Sci Technol 20 867-872. 

A number of enzymes known as sulfuric ester hydrolases (EC 3.1.6) are able to hydrolyze sulfuric acid esters. They comprise arylsulfatase (sulfatase, EC 3.1.6.1), steryl-sulfatase (steroid sulfatase, steryl-sulfate sulfohydrolase, arylsulfatase C, EC 3.1.6.2), choline-sulfatase (choline-sulfate sulfohydrolase, EC 3.1.6.6), and monomethyl-sulfatase (EC 3.1.6.16). Whereas mono-methyl-sulfatase is highly specific and does not act on higher homologues, arylsulfatase has a broad substrate specificity and is of particular significance in the hydrolysis of sulfate conjugates of phenols, be they endogenous compounds, drugs, or their metabolites [167-169],... 

Note Acrylamide may contain the following impurities acetamide, acrylic acid, acrylonitrile, copper, formaldehyde, hydroquinone, methylacrylamide, hydroquinone monomethyl ether, peroxide, propanamide, and sulfate. When acrylamide is produced using a copper catalyt, copper salts may be added to aqueous solutions at concentrations >2 ppm (NICNAS, 2002). Commercial solutions 30-50%) are usually inhibited with copper salts to prevent polymerization. In addition, solutions containing oxygen will prevent polymerization. 

Dichlorobiphenvl. PCB-1016, PCB-1232, PCB-1242, PCB-1248, PCB-1254, PCB-1260 Monoisopropyl carbonate, see Chlornronham. Pronham Monomethyl phosphate, see Malathion Monomethyl phthalate, see Dimethyl phthalate Monomethyl p3uazole, see Difenzoguat methyl sulfate Monomethyl tetrachloroterephthalate, see Chlorthal-dimethvl... 

Okaya Y,s. Ahmed M. S., Pepinsky R. Vani> V. X-ray crystallographic study of room temperature modification of monomethyl aluminium sulfate alum. Z. Cryst. 1957 109 367. 

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