Method for preparing linalool from dehydrolinalool through selective hydrogenation

Abstract

The invention discloses a method for preparing linalool from dehydrolinalool through selective hydrogenation. The method is characterized in that dehydrolinalool and a solvent are mixed and the liquid mixture passes through a fixed bed catalyst layer in a hydrogen atmosphere and undergoes a hydrogenation reaction, wherein the solvent is C2-C4 fatty alcohol; a solvent ratio is 1: (0.5 to 1.2); a liquid hourly space velocity is in a range of 2.0 to 2.5h*r<-1>; catalyst carriers are Al2O3 particles; a particle size is in a range of 3 to 5 millimeters; and active components comprise Pd, Pb and Bi. The method comprises the following steps that the active components of Pd, Pb and Bi are loaded on the catalyst carriers through immersion and high-temperature calcination to form catalyst precursors; sodium ethylene diamine tetracetate is adsorbed on the catalyst precursors through an immersion method; and catalyst finished products are obtained through reduction activation treatment in a hydrogen atmosphere. The method for preparing linalool from dehydrolinalool through selective hydrogenation has the advantages that preparation is convenient; a preparation cost is low; other deep hydrogenation side reaction inhibition processes are avoided; a conversion rate and product selectivity reach ideal levels; and a space-time yield is obviously improved.

Description

technical field [0001] The invention relates to a method for selectively hydrogenating acetylenic bond-containing compounds to prepare corresponding ethylenic bond-containing compounds, in particular to the use of Al as a carrier 2 o 3 , the active component includes the supported fixed-bed catalyst of metal Pd, Pb and Bi, the method for preparing linalool by the selective hydrogenation of dehydrolinalool. Background technique [0002] Linalool has high economic value, and it can be used as a raw material for the preparation of high-grade spices or essences, and is also an important intermediate for the synthesis of vitamin E and vitamin A. The preparation of linalool from the separated products of petroleum C5 fractions via 6-methyl-5-hepten-2-one and dehydrolinalool is an important process route for artificially synthesizing linalool at present. The main and side reactions of dehydrolinalool through selective hydrogenation to linalool are shown in the following formulas ...

AI Technical Summary

Problems solved by technology

However, the fixed-bed catalyst bed formed by such a material and a carrier with such a structural shape obviously cannot obtain an ideal catalyst load, which directly affects the space-time yield. For the technical solution disclosed in the above-mentioned Chinese patent 96110670.0, the space-time yield is only 0.31hr -1

Increasing the reaction residence time seems to be able to properly compensate for this defect. For example, the technical solution disclosed in the above-mentioned Chinese patent 00131057.7 adopts a two-stage series connection method to complete the entire hydrogenation process, and the space-time yield reaches 1.01hr. -1 However, this obviously leads to a great increase in the complexity of the production equipment and operation process

In addition, adding a certain amount of CO to hydrogen to inhibit the occurrence of deep hydrogenation and ensure the long-term stability of catalyst performance also has obvious defects, which further increases the complexity of production equipment and operating processes.

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