Method for synthesizing Alpha-tetralone through 4-phenylbutyric acid in catalytic way

Abstract

The invention provides a method, which is characterized in that in a fixed bed device, solid acid is used as a catalyst, 4-phenylbutyric acid is used as a raw material and is dissolved into 1,2-dichlorobenzene according to a certain solid-to-liquid ratio, mixed liquid continuously flows through a catalyst layer after being gasified, the reaction is carried out on a catalyst, and the Alpha-tetralone can be continuously produced. The method solves the problem that in the existing intermittent liquid phase reaction system, the catalyst is easily inactivated and cannot be cyclically used. The gas-solid phase reaction has the advantages that the contact time between reactants and catalysts can be regulated so that the reaction condition is optimized, products generated in the reaction process are continuously separated in the reaction process, and the positive direction proceeding of the reaction is favorably realized. In addition, because the fixed bed catalytic mode is adopted, generated products leave the catalytic bed layer in time in the reaction process, the reaction can be continuously operated, the on-line regeneration can also be carried out when the catalyst is inactivated, and the production efficiency is greatly improved.

Description

technical field [0001] The invention relates to a method for synthesizing α-tetralone. Specifically, it uses solid acid as a catalyst and 4-phenylbutyric acid as a raw material to continuously flow catalyze the synthesis of α-tetralone from 4-phenylbutyric acid. Hydronaphthalene method. Background technique [0002] α-tetralone (α-tetralone, also known as tetralone, 1-tetralone) is a white crystalline powder at low temperature, and a yellow liquid at room temperature. Odorless, sour taste, soluble in benzene and ethanol, insoluble in chloroform. Density 1.096, melting point 5-6°C, boiling point 127°C (13mmHg), refractive index 1.5675-1.5695, flash point 130°C. [0003] α-tetralone is an important synthetic intermediate. It can be used in the synthesis and preparation of various chiral food additives and nutritional additives. Such as the separation process of new functional nutritional additive L-carnitine and some chiral drugs. It is also used as sour agent, biochemica...

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Problems solved by technology

Literature (Cui, D.M, et al., Synthesis of 1-tetralones by intramolecular Friedel-Crafts reaction of 4-arylbutyric acids using Lewis acid catalysts. Tetrahedron Letters, 2003.44 (21): p.4007-4010.) reported in M (OTf) 3 (M is Bi, Ga, rare earth metals such as In) under catalysis, the reaction of synthesizing α-tetralone by 4-phenylbutyric acid, but the cost of this class catalyst is higher and is difficult to obtain in a large amount, makes its suitability for industrialized production limit

Literature (Hiroki, K., et al., Efficient synthesis of 1-tetralones from 4-arylbutyric acids by combined use of solid acid catalysts and microwave irradiation. Chemistry Letters, 2008.37 (3): p.320-321.) reported Beta The application of molecular sieves in this F-C reaction liquid solid phase and microwave conditions, and achieved a good catalytic effect, but the reaction is intermittent

[0009] Most of the catalysts involved in the above methods are traditional liquid acid catalysts, and most of the systems used are liquid phase reaction systems, which have problems such as polluting the environment, complex processes, difficult separation of catalysts, and difficulty in reusing.

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