- Jamie Callan, James Allan, Charles L. A. Clarke, S. Dumais, David A. Evans, Mark Sanderson, ChengXiang Zhai. 2007. Meeting of the MINDS. Abstract: This invention relates to a process for the synthesis of ortho-sulfobenzoic acid anhydride which comprises heating a 2-sulfohalide benzoate in the presence of a catalytic amount of a Friedel-Crafts catalyst. Especially preferred in the practice of this invention is the reaction of ortho-carbomethoxybenzenesulfonyl chloride in the presence of a zinc or iron halide to produce ortho-sulfobenzoic acid anhydride.
