Method for preparing cyclopentanol from cyclopentene through indirect hydration method

Abstract

The invention relates to a method for preparing cyclopentanol from cyclopentene through an indirect hydration method. The method comprises steps that: liquid phase cyclopentene and acetic acid are subject to an addition reaction with a fixed-bed catalyst, such that cyclopentyl acetate is obtained, wherein the catalyst is sulfonic cation exchange resin with a mass exchange capacity of 3-5.5mmol / g;the product of the addition reaction is processed through rectification separation, such that refined cyclopentyl acetate is obtained; the refined cyclopentyl acetate is subject to an ester exchange reaction with methanol under the existence of a catalyst CaO, such that cyclopentanol and methyl acetate are produced; the produced methyl acetate is removed during the reaction process; the product of the ester exchange reaction is filtered, such that the catalyst is removed; and the obtained product is processed through rectification separation, such that the product cyclopentanol is obtained. The method provided by the invention provides substantial positive effects. The addition reaction and the ester exchange reaction have relatively high conversion rate and selectivity, and an average overall yield reaches approximately 80%. More importantly, no substance with high acidity and corrosivity is appeared in the reaction system during the whole reaction process. The raw materials which are not reacted can easily be recovered and reused, and almost no environment pollution is caused.

Description

technical field [0001] The invention relates to a method for preparing cyclopentanol, in particular to a method for preparing cyclopentene through addition reaction with acetic acid and further through transesterification. Background technique [0002] Cyclopentanol is an important fine chemical raw material. It can be used not only for the preparation of the important fragrance intermediate cyclopentanone, but also for the manufacture of antibacterial and antiallergic drugs with higher value. It is one of the most important industrial production methods to obtain cyclopentanol through hydration reaction from the cyclopentene obtained by separating the C5 fraction produced by the by-product of petroleum cracking to ethylene, which includes two processes of indirect hydration and direct hydration. The advantage of direct hydration is that the process route is simple, and the pollution is small and friendly to the environment, but the disadvantage is that the single-pass conve...

AI Technical Summary

Problems solved by technology

The advantage of direct hydration is that the process route is simple, and the pollution is small and friendly to the environment, but the disadvantage is that the single-pass conversion rate of the reaction is very low. Although the selectivity can reach about 98%, the ideal reaction yield cannot be obtained due to the too low conversion rate. Rate

Chinese patent ZL200410017401.4 introduces an improved method for preparing cyclopentanol by direct hydration of cyclopentene. The single-pass conversion rate is significantly improved under the premise of ensuring high selectivity, but the single-pass yield still cannot exceed 10%.

The indirect hydration process in the prior art is generally that cyclopentene is first sulfonated with sulfuric acid to generate cyclopentyl sulfate, and then cyclopentyl sulfate is hydrolyzed with water to generate cyclopentanol, and sulfuric acid is produced as a by-product. There is a high concentration of sulfuric acid in the system, so the requirements for corrosion resistance of equipment are extremely high, the investment and maintenance costs of production equipment are expensive, and sulfuric acid is difficult to recycle and reuse, resulting in very serious pollutant emissions

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