Process for the preparation of C10-C30-alkenes by partial hydrogenation of alkynes on fixed-bed palladium-supported catalysts

摘要

A process for the preparation of alkenes by partial hydrogenation of alkynes in the liquid phase at temperatures of 20 to 250 ° C and hydrogen pressures from 0.3 to 200 bar on palladium-fixed-bed support catalysts obtained by heat treatment of the support material in the air, cooling, applying a palladium compound and optionally additionally for doping purposes other metal ions, molding and processing to monolithic catalyst elements are available, which is characterized in that A) alkynes employing having 10 to 30 carbon atoms, as starting compounds, B) applying the palladium compound and optionally the other metal ions by impregnating the annealed and cooled support material with a palladium salts and optionally other metal ion-containing solution and subsequent drying on the support material and C) that is added to the hydrogenation 10 to 2000 ppm Kohlenmomoxid (CO) or can be a corresponding amount of CO in the liquid phase, resulting from slight decomposition of an added to the reaction mixture compound which eliminates CO under the reaction conditions.; Particularly advantageously, the process is designed, if one carries out the partial hydrogenation in a tubular reactor in a downflow or upflow mode with product recycling at cross-sectional loadings of from 20 to 500 m ³ / m ² * h. Particularly suitable method for the preparation of 3,7,11,15-tetramethyl-1-hexadecen-3-ol (isophytol), 3,7,11-trimethyl-1-dodecen-3-ol is (tetrahydronerolidol), 3 , 7,11-trimethyl-1,4-dodekadien-3-ol, 3,7,11-trimethyl-1,6-dodekadien-3-ol (dihydronerolidol), 3,7-dimethyl-oct-1,6- dien-3-ol or 3,7-dimethyl-oct-1-en-3-ol from the corresponding alkynes.