| abstract |
A widely used process for the production of carotenoidsnby the Wittig reaction consists of the Wittig reaction in a polarnCarry out reaction medium in such a way that neither all reactantsnthe carotenoid thus produced was still significantly dissolved in the reaction mediumnare. A polar, toxicological is particularly suitable as the reaction mediumnharmless solvent (mixture), which when added water innof a quantity up to about 30 vol.% remains single-phase and the resultingnTriarylphosphine oxide is able to dissolve well. Lower alcohols and acetone thannsole solvents or as mixtures with one another and / or withnWater, are particularly suitable. Using this method it isnpossible to work much more concentrated, the regeneration of the solventnand to simplify the administration of law in general and to suchntoxicologically questionable solvents such as halogenated hydrocarbonsnto renounce. |