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dimethyl sulfate

Product name dimethyl sulfate
Synonyms methyl sulfate
sulfuric acid dimethyl ester
GOST no data
CAS 77-78-1

Dimethyl sulfate (CH3)2SO4 is a colorless, clear, oily, odorless liquid. It has a good solubility in ethanol, diethyl ether, tetrahydrofuran (THF), dioxane, acetone, arenes. It is boundedly soluble in carbon disulfide, aliphatic hydrocarbons. Dimethyl sulfate is only slightly soluble in water (2.8% by mass, decomposes upon dissolving). As an active methylating agent it liquid dimethyl sulfate reacts violently with ammonia and amines yielding methylated products mixture. Tertiary amines react to form quarternary ammonium salts. Dimethyl sulfate easily methylates alcohols, phenols, mercaptanes, carboxylic acids in the presence of alkaline metal alcoholate or alkaline solution in alcohol as a catalyst. It methylates CH-acids in aprotic solvents. The mechanism that typically occurs with dimethyl sulfate is a SN2 reaction.

Dimethyl sulfate is likely carcinogenic, and is considered toxic. Dimethyl sulfate is absorbed through the skin, mucous membranes, and gastrointestinal tract. Delayed toxicity allows potentially fatal exposures to occur prior to development of any warning symptoms.


  • by distillation of methyl hydrogen sulfate at 150-160°C. Methyl hydrogen sulfate is produced by interaction of methanol with 60% oleum in 1:4 proportion by mass. By-product of this reaction, dimethyl ether is also used to manufacture dimethyl sulfate:

    SO3 + CH3OH --> CH3SO4H
    CH3SO4H --> (CH3)2SO4 + H2SO4

  • By the reaction of dimethyl ether with oleum:

    SO3 + CH3OCH3 --> (CH3)2SO4


    Dimethyl sulfate is used:

  • as a methylating agent in laboratory synthesis and in chemical industry;
  • as an intermediate in making quarternary ammonium salts and bases which used as detergents, surfactants, fabric softeners, pharmaceuticals and so on;
  • to methylate carboxylic and mineral acids, alcohols, thioalcohols;
  • with DNA for the base-specific cleavage of guanine by rupturing the imidazole rings present in guanine. This process can be used to determine base sequencing, cleavage on the DNA chain;
  • as an intermediate in manufacturing pesticides, insecticides, dyes, rubber chemicals, photographic chemicals, water treatment chemicals, flavors and others;

  • Manufacturer(s) no data
    Chemical structure of dimethyl sulfate

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