Recovery of dimethyl sebacate from an isomeric mixture of C.sub.12 esters

In the process of producing dimethyl sebacate by contacting, in a reaction inert solvent, methyl penta-2,4-dienoate at a temperature of 30.degree. to 150.degree. C. under an inert atmosphere with a catalytic amount of a homogeneous palladium (II) complex of the formula ##STR3## wherein Q is phosphorous or arsenic;

• R is alkyl, trichloroalkyl, tribromoalkyl or trifluoroalkyl having from 1 to 6 carbon atoms or aryl having 6 to 12 carbon atoms and R' is alkyl, aminoalkyl or alkoxy having 1 to 6 carbon atoms or aryl or aryloxy having 6 to 12 carbon atoms and hydrogenating resulting reaction mixture at a hydrogen pressure of from 1 to 50 atmospheres and at a temperature of from 30.degree. to 100.degree. C. in the presence of a catalytic amount of a hydrogenation catalyst which converts unsaturated ester to saturated ester, the improved method of recovering dimethyl sebacate from said reaction mixture containing hydrogenated methyl penta-2,4-dienoate, reaction inert solvent, dimethyl sebacate, other dimethyl esters of C.sub.10 -dicarboxylic acids, an ester of a C.sub.15 -tricarboxylic acid and other minor heavy by-products which comprises removing hydrogenated methyl penta-2,4-dienoate and reaction inert solvent by fractional distillation at reduced pressure, separating the ester of the C.sub.15 -tricarboxylic acid and other minor heavy by-products by distilling off the dimethyl ester of the C.sub.10 -dicarboxylic acids including dimethyl sebacate at reduced pressure and stepwise recrystallizing dimethyl sebacate from resulting mixture of the esters of the C.sub.10 -dicarboxylic acids using a solvent selected from the group consisting of acetone, diethyl ether, tetrahydrofuran, alkanols having 1 to 4 carbon atoms, aromatic hydrocarbons having 6 to 12 carbon atoms, alkanes and alkenes having 5 to 8 carbon atoms and a mixture of one of said solvents which is miscible with water, and water.