Method for synthesizing o-hydroxy phenetole

Abstract

A method for synthesizing an O-hydroxy phenyl ether relates to a method for applying a novel catalyst to prepare the O-hydroxy phenyl ether, which is synthesized through a gas-phase alkylation betweenthe cathecol and the ethanol. The composition expirical formula of the active center of the catalysts is Al< 1 >PX; wherein, X is Cr, Mg, V or Zr, a is more than or equal to 0.9 and less than or equal to 1.5 and b is more than 0 and is less than or equal to 0.3; the aluminum nitrate is used as the aluminum source, the phosphoric acid, the ammonium dihydrogen phosphate and the ammonium phosphate or the ammonium phosphate are used as the phosphorous source and the nitrate, the zirconium oxychlorid and the ammonium metavanadate of Mg and Cr are used as the raw materials of X; the reaction between the catechol and the ethanol is carried out in a fixed bed reactor and the molar ratio of the ethanol to the catechol ranges from 2 to 7:1; the ratio of the mole number of the catechol tothat of the catalysts every hour ranges from 0.05 to 0.75 as Al, the reaction space velocity ranges from 0.1 to 1.5h<-1> as the volume of the liquid and the reaction temperature ranges from 533K to 593K. The catalysts adopted by the invention have simple compositions, the raw materials are simple and easy to be obtained and the specific surface area is larger; the invention delivers high yield andhigh stability for the target reaction.

Description

technical field [0001] The invention relates to a method for synthesizing o-hydroxyphenetole through the gas-solid phase alkylation reaction of catechol and ethanol, in particular to a method for preparing o-hydroxyphenetole with a novel catalyst. Background technique [0002] O-hydroxyphenethyl ether (ethyl wood phenol) is an important fine chemical intermediate and chemical raw material in spices, medicine, agriculture and other industries, and has a wide range of uses. [0003] As a raw material for synthetic perfume (vanillin), o-hydroxyphenethyl ether has a large demand and is very popular in the international market. Vanillin is a precious broad-spectrum high-grade spice, widely used in fixatives, odor-changing agents, flavoring agents, and in the production of cosmetics, soaps, cakes, candies, beverages, tobacco, and baked foods; As a fragrance additive, it is favored by the international fragrance industry for its small amount of addition and unique aroma. Its deman...

AI Technical Summary

Problems solved by technology

A variety of solid acid catalysts are used for this reaction, such as kaolin, oxides and mixed oxides, molecular sieves, phosphates, supported catalysts, etc., but most of these catalysts have the disadvantage of poor activity (selectivity or stability)

[0005] European patent (EP 0 509 927 A1) reported Al a P b Ti c Si d x e o f The reaction of catechol and ethyl (methyl) alcohol on the catalyst to synthesize guaiacol, there are two examples in the patent, under the reaction conditions of 553K, catechol / ethanol=1: 3.44 (mol), Al 1 P 1.1 Ti 0.1 Si 0.17 o 4.79 The conversion rate of catechol on the catalyst is 54.2%, and the selectivity of o-hydroxyphenethyl ether is 97.2%; Al 1 P 1.13 Ti 0.1 Si 0.17 K 0.1 o 4.97 The conversion rate of pyrocatechol on the catalyst is 40.1%, and the selectivity of o-hydroxyphenetole is 98.6%. In addition, the catalyst in this patent has the disadvantages of complex preparation method, many constituent elements, and small specific surface area.

[0006] Although catalysts such as Al-P-O, Al-P-Ti-O, and Al-P-Ti-Si-O have good conversion and yield, and the stability can reach about 200h, there are still problems of activity decline and carbon deposition. Phenomenon

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