The present invention relates to an improved process of manufacturing high purity Vanillin, which is used for variety of industrial applications. The process includes the reaction of Guaiacol & Glyoxalic Acid under alkaline conditions, recovery of un-reacted Guaiacol, Oxidative decarboxylation, neutralization, extraction & isolation of Crude Vanillin, selective removal of Ortho - Vanillin & crystallization of Crude Vanillin. The Vanillin so prepared has atleast 99% purity. The process ensures minimization of Cannizzaro reaction, enhancing Para selectivity to yield Para - Hydroxy Methoxy Mandelic Acid recovering & recycling of un-reacted Guaiacol recovering, reactivating & recycling of Copper Oxide used as catalyst
