Preparation method of canthaxanthin

The invention discloses an efficient and environment-friendly process for preparing canthaxanthin, beta carotene is used as a raw material, an oxidation reaction is carried out under the action of a catalyst to generate a canthaxanthin crude product, and the catalyst is a transition metal modified alkaline earth metal oxide. Compared with the prior art, the method has the following advantages: (1) according to the process, a traditional oxidation reaction and an isomerization reaction are coupled, the canthaxanthin crystal can be obtained through one-step operation, the total yield of oxidation and isomerization in series is greater than 85%, the total purity of the obtained crystal is greater than 97%, and the total trans content is higher than 92%; (2) compared with the traditional synthesis process, the production capacity of the canthaxanthin obtained by the method is greatly improved; and (3) the process is a solvent-free system, inorganic salt water liquid required by the traditional process is not used