Process for synthesizing p-tertiary butyl benzaldehyde

Abstract

The invention discloses a method for synthesizing p-tert-butylbenzaldehyde. The method comprises the following steps: a normal atmosphere heterogeneous catalytic oxidation method is adopted; p-tert-butyltoluene as a raw material, sufficient oxygen as an oxygen source and n-hydroxyphthalimide as a free radical evocating agent in an acetonitrile solution react for 4 to 7 hours at a temperature between 50 and 70 DEG C under the condition of a catalyst to directly synthesize the p-tert-butylbenzaldehyde; and the catalyst is a cobalt-loaded mesoporous molecular sieve or a cobalt- and manganese-loaded mesoporous molecular sieve. The method use the cobalt-loaded mesoporous molecular sieve or the cobalt- and manganese-loaded mesoporous molecular sieve as the solid-phase catalyst; compared with the prior liquid-phase catalyst, the target product is easier to separate after reaction; a reactant can rapidly contact catalytic activity center; product molecules rapidly escape from a pore canal, thereby avoiding deep oxidation and improving the selectivity of aldehyde; in addition, micro n-hydroxyphthalimide as the free radical evocating agent is added to the system to trigger the chain transmission reaction of free radicals.

Description

(1) Technical field [0001] The invention relates to a method for selectively oxidizing p-tert-butyl toluene to synthesize p-tert-butyl benzaldehyde under mild conditions. (2) Background technology [0002] 4-tert-butylbenzaldehyde is an important intermediate in fine chemical products such as medicines, dyes, flavors and fragrances, and is in great demand in the synthesis of flavors and fragrances lyral. [0003] There are many synthetic methods of p-tert-butylbenzaldehyde, and the traditional synthetic methods include stoichiometric oxidation and benzyl chloride hydrolysis. The stoichiometric oxidation method is in MnO 2 , concentrated H 2 SO 4 Directly oxidize p-tert-butyltoluene to synthesize p-tert-butylbenzaldehyde under the influence of the action. This process has equipment corrosion and serious pollution, and generates a large amount of MnSO 4 Disadvantages such as difficulty in recovery, high production cost, and difficulty in product separation. Although the b...

AI Technical Summary

Problems solved by technology

The stoichiometric oxidation method is in MnO 2 , concentrated H 2 SO 4 Directly oxidize p-tert-butyltoluene to synthesize p-tert-butylbenzaldehyde under the influence of the action. This process has equipment corrosion and serious pollution, and generates a large amount of MnSO 4 Disadvantages such as difficult recovery, high production cost, and difficult product separation

Although the benzyl chloride hydrolysis process is mature, it has many reaction steps and low yield, and the product contains trace organic chlorine that is not easy to remove, which is carcinogenic, and produces a large amount of sodium chloride or calcium chloride wastewater in the subsequent treatment section , causing serious pollution to the environment

[0004] Chinese patents (CN1944368A, CN1315316 A) report that methyl p-tert-butylbenzoate is hydrogenated to synthesize p-tert-butylbenzaldehyde. This process (aromatic hydrocarbons are oxidized into carboxylic acids, and aromatic aldehydes are synthesized through esterification and hydrogenation) is complicated.

In the published literature reports, researchers are committed to using cheap and clean oxygen or hydrogen peroxide as the oxygen source, under the action of homogeneous Co-Br binary or Co-Mn-Br ternary composite catalysts, liquid phase direct oxidation of tertiary Butyltoluene synthesizes p-tert-butylbenzaldehyde, but halide ion is used as free radical initiator in the system, Br - Corrosion of expensive titanium equipment is severe, and the generated CH 3 Br(g) destroys the atmospheric ozone layer