Patent ID: 7102028

Claim:
A method for producing 3,5-di-tert-butyl-4-hydroxybenzoic acid comprising: (1) providing 2,6-di-tert-butylphenol which may contain up to 0.5% by weight of 3,3′,5,5′-tetra-tert-butyl-4,4′-dihydroxybiphenyl; (2) reacting sodium methoxide with an excess amount of the 2,6-di-tert-butylphenol, which is excess of sodium methoxide, to give sodium 2,6-di-tert-butylphenolate; and (3) reacting the sodium 2,6-di-tert-butylphenolate obtained in step (2) with carbon dioxide to give 3,5-di-tert-butyl-4-hydroxybenzoic acid.