Diethyl phthalate (DEP, phthalic acid diethyl ester) is clear oily liquid. Soluble in ethanol, chloroform; almost insoluble in water.
Diethyl phthalate is produced by the reaction of phthalic anhydride with ethanol in the presence of concentrated sulphuric acid as a catalyst. After neutralization with water alkali metal hydroxides or carbonates, the excess ethanol is recovered and recycled and phthalates are purified by vacuum distillation.
Diethyl phthalate is used as plasticizer for cellulose esters, vinyl polymers, rubbers;
As a fixative in fragrances to improve the stability and other characteristics of the main ingredients;