Dimer acid esters by simultaneous dehydration and polymerization of technical methyl ricinoleate

Filtrol 13 may be used to dehydrate methyl ricinoleate with simultaneous dimerization and polymerization of the linoleate esters formed. Hydrolysis of the ester group is avoided by the use of xylene as an azeotroping solvent and the preferred method of reaction is the dropwise addition of the ester to a stirred suspension of catalyst in xylene. Products prepared by this technique had a dimer/polymer ratio of about 5 when the yield was 50%. The acid value of the polymer was 7 and of the recovered monomer 3–4.