Carbamates are organic compounds derived from carbamic acid (NH2COOH). The ester form, ethyl carbamate is obtained by esterifying the free carboxylic group with ethyl alcohol. Thus it has the structural formula NH2CO2C2H5 or its N-substituted analogs, viz. NHRCO2C2H5, or NR2CO2C2H5. Consequently ethyl carbamate has two functional groups, 1) an amine / substituted amine group and 2) an ester group. Carbamate esters are also called urethanes. These units have great tendency to polymerize through the formation of amide (-CONH-) linkages to form gigantic molecules known as polyurethanes, or high load-bearing rubber like foams.