| abstract |
The present invention relates to novel processes for the manufacture of chroman derivatives such as α-tocopherol (TCP) and alkanoates thereof, especially α-tocopheryl acetate (TCPA), whereby at least one step of the processes is carried out in the presence of a Lewis acid or a mixture of a Lewis acid with a Bronsted acid as the catalyst under pressure, preferably at an absolute pressure of at least 1.1 bar. As starting materials for the manufacture of TCP and its alkanoates either a mixture of 2,3,5-trimethylhydroquinone (TMHQ) or 2,3,6-trimethylhydroquinone-1-alkanoate (TMHQA) and a compound selected from the group consisting of phytol (pH), isophytol (IP) and (iso)phytol derivatives or 2-phytyl-3,5,6-trimethyl-hydroquinone (PTMHQ)/3-phytyl-2,5,6-trimethylhydroquinone-1-alkanoate (PTMHQA) and/or an isomer thereof are used. Suitable Lewis acids are indium(III) salts and scandium(III) salts. Suitable acid mixtures are iron/iron(II) chloride/hydrogen chloride and zinc(II) chloride/hydrogen chloride. |