Dimethyl Sulfate

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dimethyl sulfate

[‚dī′meth·əl ′səl‚fāt]
(organic chemistry)
(CH3)2SO4 Poisonous, corrosive, colorless liquid, boiling at 188°C; slightly soluble in water, soluble in ether and alcohol; used to methylate amines and phenols. Also known as methyl sulfate.

Dimethyl Sulfate


the dimethyl ester of sulfuric acid, (CH3)2SO4; a colorless liquid. Melting point, −31.4°C; boiling point, 188. 6°C; density, 1.3283 g/cm3 (20°C); index of refraction n20D. 1.3874. Highly toxic. Dimethyl sulfate is slightly soluble in water (2.8 percent), has limited solubility in hydrocarbons, and is completely miscible with alcohols and ethers. When treated with water it gives methyl sulfate and methanol or methyl ether plus sulfuric acid. In organic synthesis it is used as a methylating agent, for example:

ROH + (CH3)2SO4 → ROCH3


KCN + (CH3)2SO4 → CH3CN

Dimethyl sulfate is made, for example, by distilling a mixture of CH3OH and 60-percent oleum.