Method for preparing benzaldehyde by toluene oxidation

Abstract

The invention discloses a preparation method of benzaldehyde. According to the method disclosed by the invention, by taking toluene as a raw material, a metal as well as a metal oxide loaded on a carrier as a catalyst, peroxide as a co-catalyst, oxygen as an oxygen source and methanol as a reaction solvent, the reaction time is 1-80 hours, the reaction temperature is 25-120 DEG C, the pressure is 0.1-6.0MPa, the conversion rate can reach 10-50% and the selectivity can reach 60-90%. The method disclosed by the invention has the advantages of simple process, low cost, environmental friendliness, low energy consumption, high authenticity of benzaldehyde, easily separable and reusable catalyst and the like.

Description

technical field [0001] The invention relates to a method for preparing benzaldehyde, in particular to a method for preparing benzaldehyde by oxidation of toluene. Background technique [0002] Benzaldehyde exists widely in the plant kingdom, especially in Rosaceae plants, mainly in the form of glycosides in the bark, leaves or seeds of plants, such as amygdalin in bitter almonds. Benzaldehyde occurs naturally in essential oils such as bitter almond oil, ageratum oil, hyacinth oil, and ylang ylang oil. It is also sometimes called bitter almond oil. As an important chemical raw material, benzaldehyde is used to produce lauric aldehyde, lauric acid, phenylacetaldehyde and benzyl benzoate, etc. It can also be used to determine ozone, phenol, alkaloids and methylene reagents next to carboxyl groups. As a special top-note fragrance, it is used in trace amounts in floral fragrance formulations. [0003] There are three main types of traditional industrial production methods of b...

AI Technical Summary

Problems solved by technology

This method requires acetic acid as a solvent, and consumes a large amount of hydrogen peroxide, resulting in a large amount of waste water and complicated processes.

Therefore, although the reaction conditions of this method are mild, it is difficult to realize industrial production

In 2014, Wei Deng et al. used metal porphyrin complexes to catalyze the oxidation of toluene. When the conversion rate of toluene reached 41%, the selectivity of benzaldehyde was only 28.61%. This method used expensive metal complexes. Catalysts, more by-products, increased production costs, and caused greater pollution

In summary, the existing technology has many shortcomings such as complex process, serious pollution, high cost, high energy consumption, and low selectivity of benzaldehyde.