ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Zinc catalyst recycling in the preparation of (all-rac)-α-tocopherol from trimethylhydroquinone and isophytol
Juraj Gömöry, Milan Králik, and Alexander Kaszonyi
Zentiva, a.s., Nitrianska 100, 920 27 Hlohovec, Slovakia
Department of Organic Technology, Slovak University of Technology, Radlinského 9, 812 37 Bratislava, Slovakia
Abstract: Recycling of ZnCl2 as a catalyst in the cyclocondensation of trimethylhydroquinone and isophytol to all-rac-α-tocopherol was studied. ZnCl2 was recycled at over 98 % efficiency in required purity by repeated extraction of the reaction streams with water, followed
by switching of solvent to butyl acetate and then back to water. Recycled ZnCl2 had no negative effect on the yield of all-rac-α-tocopherol (maintaining over 90 %) at nearly total conversion of isophytol and only a 3 % molar excess of trimethylhydroquinone.
Keywords: all-rac-α-tocopherol – trimethylhydroquinone – isophytol – ZnCl2 – catalyst recycling – mechanism
Full paper is available at www.springerlink.com.
Chemical Papers 65 (4) 427–436 (2011)
Sunday, November 28, 2021