Urethane(redirected from urethan)
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(also carbamate), NH2COOR, any of the esters of carbamic acid (H2NCOOH) that are unknown in the free state. Urethanes are colorless crystalline compounds. Unlike the acid, the esters are stable; thus, ethylurethane (H2NCOOC2H5; sometimes simply called urethane, from which the name of the entire class is derived) has a melting point of 49°C and a boiling point of 184°C.
Urethanes are prepared by, among other methods, reacting alcohols with urea [CO(NH2)2] or isocyanic acid (HNCO). N-substituted urethanes, formed from the reaction of isocyanates (RNCO) with alcohols and phenols, are used in the identification of phenols. Polyurethanes are widely used in industry in the form of rubbers, adhesives, varnishes, and fibers. Certain substituted urethanes are used as pharmaceuticals; examples include proserine methyl sulfate, carbachol, and propanidid.