Preparation of 4-Vinylphenol Using pHCA Decarboxylase in a Two-Solvent Medium

An efficient synthesis of 4-vinylphenol (4-VP) from para-hydroxycinnamic acid (pHCA) that uses the enzyme para-hydroxycinnamic acid decarboxylase (PDC) in a two-phase aqueous−organic solvent has been developed. The 4-VP titer and catalyst productivity (17 g L-1; 1010 g 4-VP isolated g-1 catalyst) greatly exceed those for intact cells expressing PDC or calcium alginate bead-immobilized PDC-expressing cells in an aqueous buffer (5 g L-1; 4.4 to 64 g of isolated 4-VP per gram of catalyst). In this two-phase reaction design, the organic solvent (e.g., toluene) enabled continuous extraction of 4-VP into the organic phase and either its recovery as a crystalline solid with low color or its direct conversion to 4-acetoxystyrene.