Method of preparing thymol

Abstract

The invention provides a method for preparing thymol at normal pressure. The method adopts resordinol and isopropanol as raw materials, and the reaction is carried out in a fixed bed reactor, and a catalyst is filled into the reactor. The method is characterized in that the mol ratio of resordinol to isopropanol is between 1:1 and 1:6; the reaction temperature is between 200 and 350 DEG C; the reaction time is 4 to 7 hours; the reaction is carried out at the normal pressure; and the reactants are in a gas state, and the carrier gas is inert gas not taking part in the reaction. The catalyst is Gamma-Al2O3 which undergoes the following process: stirring and soaking Gamma-Al2O3 in sulphuric acid; filtrating, drying and roasting the Gamma-Al2O3; and then carrying out cooling, tabletting and sieving on the Gamma-Al2O3 to take 100 to 80 meshes of finished product for standby. The method solves the defects in the prior art, and has the characteristics that the reaction conditions are easily satisfied; and the reaction can be carried out at the normal pressure, and the method has little byproducts, good selectivity, long service life of the catalyst, and the like. The method has higher use value.

Description

technical field [0001] The invention relates to the field of chemical technology, in particular to a preparation method of thymol. technical background [0002] Thymol is a commonly used spice in industry, and it can also be used as an industrial fungicide and medicine. At the same time, it is also the primary raw material for the synthesis of many chemicals. [0003] The way that the synthesis of thymol usually adopts has: (1) take m-cresol, oleum and isopropanol as raw materials, sulfuric acid as catalyst, synthesize thymol through sulfonation and alkylation two-step reaction. The disadvantage of this method is that the reaction equipment is required to have high corrosion resistance, and the yield of thymol is low, and a large amount of waste acid is produced in the production process, which seriously pollutes the environment. (2) α-pinene can be catalyzed to oxidize to obtain verbenone, and then catalyzed to obtain thymol through catalytic cracking. The yield of this s...

AI Technical Summary

Problems solved by technology

Although this method technique is simple, and the productive rate of thymol is high, but the dehydrogenation catalyst that it uses, preparation process is complicated and life-span is short