Patent ID: 9126902
Filing Date: 2015-09-08
Classification: C07C

Abstract:
1. A method for preparing 3,5-bis(cyanato)benzoate esters, comprising: preparing a mixture 3,5-dihydroxybenzoic acid and at least one aliphatic and/or aromatic alcohol (ROH), wherein R is an aliphatic and/or aromatic component of said aliphatic and/or aromatic alcohol; heating said mixture in the presence of an acid catalyst; removing unreacted alcohol by distillation; purifying said 3,5-dihydroxybenzoate ester (I) from said mixture: treating said ester (I) with cyanogen halide in the presence of at least one base and at least one solvent; isolating a 3,5-bis(cyanato)benzoate ester (II) from said treated ester (I): and purifying said 3,5-bis(cyanato)benzoate ester (II) to attain a cyanate ester monomer capable of forming thermally cured resins.