Method for efficiently preparing benzaldehyde by using air as oxidation agent to catalyze benzyl alcohol in alkali-free water phase system at room temperature

Abstract

The invention discloses a method for efficiently preparing benzaldehyde by using air as an oxidation agent to catalyze benzyl alcohol in an alkali-free water phase system at room temperature. According to the method, a precious metal Pt / metal oxide (zinc oxide, titanium oxide or reduced bismuth oxide) composite system is used as a catalyst, and the benzyl alcohol and the catalyst are dispersed into water and are then continuously stirred for 5-10h at low temperature in a dark place; the generation selectivity of the benzaldehyde can reach 99% or above, and the yield of the benzaldehyde is maintained within a range of 75-100% with the different types of carriers. The method has the positive effects that 1, a reaction can be carried out at the lower temperature such as room temperature 25 DEG C; 2, the cheap air is taken as the oxidation agent, so that the problem of environmental pollution caused by high valence metal such as chromium and manganese which are used as oxidation agents can be solved; 3, alkaline substances are not added into the reaction system as catalyst promoters; 4, the reaction process is basically free from a side reaction, and the generation selectivity of the benzaldehyde is maintained to be 99% or above; 5, equipment and operation technology of the reaction are simple.

Description

Technical field [0001] The invention belongs to the field of nano material preparation and organic green catalysis, and specifically relates to a method for catalytically converting benzyl alcohol to benzaldehyde in an alkali-free water phase system at room temperature using air as an oxidant. Background technique [0002] Benzaldehyde is an important organic chemical intermediate and has extremely important applications in fine chemical industries such as medicine, plastics, and flavors. Therefore, the preparation of benzaldehyde is a very important organic reaction. At present, the industrial production of benzaldehyde at home and abroad usually adopts benzyl chloride hydrolysis and toluene chlorination hydrolysis. The process flow is long and complicated, and the reaction is difficult to control. The product contains toxic chloride or chloride ions and emits corrosive gases and organic waste, which greatly limits the application of benzaldehyde in the pharmaceutical and perfum...

AI Technical Summary

Problems solved by technology

[0003] In view of the deficiencies in the prior art, the object of the present invention is to solve the problem of low selectivity caused by peroxidation in the preparation of benzyl alcohol from benzyl alcohol, aiming to provide a safe, green and efficient conversion route of benzyl alcohol to benzaldehyde, by utilizing Pt is loaded on the metal oxide carrier (zinc oxide, titanium oxide and reduced bismuth oxide), under the condition of non-alkali aqueous phase at room temperature, using air as the oxidant to effectively improve the selectivity of benzyl alcohol oxidation to benzaldehyde, the reaction system is both It does not involve toxic substances such as chromium and manganese as oxidants, does not involve organic reagents such as toluene and chloroform as solvents, and does not need to add alkaline substances as cocatalysts, which effectively reduces environmental pollution. It is a completely green catalytic conversion of benzene Pathway from Methanol to Benzaldehyde

Images