Method for preparing aromatic aldehyde by catalytic oxidation of toluene compound

Abstract

The invention discloses a method for preparing aromatic aldehyde by selective catalytic oxidation of a toluene compound through a transition metal modified MFI molecular sieve. The method comprises the following steps: under the catalytic action of the transition metal modified MFI molecular sieve, with bromide or molecular bromine as an initiator and with oxygen or air as an oxygen source, performing reaction on a substrate toluene compound, and adding a polar organic solvent in the reaction system. The preparation method of the aromatic aldehyde by catalytic oxidation has the advantages that the percent conversions of reactants are high and the selectivity of a target product is high. In addition, a catalyst is simple to prepare, easy to separate and long in service life; the reaction conditions are mild and environmental friendly, and the application prospect is good.

Description

【Technical field】 [0001] The invention relates to the field of catalytic organic synthesis, in particular to a method for preparing aromatic aldehydes by catalytic oxidation of toluene compounds. 【Background technique】 [0002] Aromatic aldehydes are important raw materials in the production of fine chemicals. As intermediates in medicine, dyes, spices, pesticides, etc., they have good market prospects. For example, nitrobenzaldehyde is the main raw material for the synthesis of new cardiovascular drugs such as nifedipine and nimodipine; o-chlorobenzaldehyde can be directly used as an electroplating whitening agent, and also as an intermediate for tear gas products; p-chlorobenzaldehyde can be used It is used in the synthesis of herbicide Maidi San, plant growth regulator paclobutrazol and uniconazole; p-bromobenzaldehyde is also the main intermediate in the industrial synthesis of benzene-containing compounds. [0003] In the industry, the chlorination and hydrolysis of to...

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Problems solved by technology

[0003] In the industry, the chlorination and hydrolysis of toluene compounds is mainly used to produce aromatic aldehydes. The method has the disadvantages of difficult to control the oxidation depth and serious equipment corrosion, and has brought serious environmental problems.

The traditional oxidation method of toluene compounds is to use heavy metal oxides such as potassium dichromate, potassium permanganate, chromium trioxide-pyridine, etc., and the reaction generates a large amount of heavy metal waste, which seriously pollutes the environment

[0004] From the perspective of environmental protection, using air or oxygen as a clean oxygen source to realize the green selective oxidation of side chain methyl groups of toluene compounds has received widespread attention and some progress has been made, but due to the air oxygen oxidation of toluene compounds generally requires At a higher temperature, the oxidation product aldehyde is easily further oxidized to the corresponding acid, and the selectivity of the reaction to aldehyde is poor

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