Purification process for epoxypropane

Abstract

The invention provides a method for purifying propylene oxide, and relates to a method for separating methanol, methyl formate and aldehyde in the propylene oxide through extracting and rectifying by continuously operated reactions, wherein, the aldehyde can be formaldehyde, acetaldehyde and propionaldehyde. The method comprises the following steps of: adding an alkaline solution containing ammonia or aminium salt above a feeding point of crude propylene oxide; and a reflux ratio of a condensate liquid selected to return a reactive rectification tower to the purified propylene oxide as a product is between 1 and 5, thereby the content of the methanol in the propylene oxide is less than 600ppm, the content of the methyl formate is less than 100ppm, and the content of the aldehyde is less than 100ppm.

Description

Technical field [0001] The invention relates to a method for purifying propylene oxide, in particular to a method for separating methanol, methyl formate and aldehydes in propylene oxide through reactive extraction rectification in continuous operation. Background technique [0002] Under the action of a catalyst, propylene and hydrogen peroxide react in a methanol solution to form a dilute propylene oxide solution. The solution is removed from the propylene and unreacted hydrogen peroxide contained in it through one or more steps, and obtained for reactive extraction and rectification. In the crude propylene oxide, the methanol content is 20% to 70%, the methyl formate is higher than 300ppm, and the aldehyde is higher than 500ppm. [0003] Through simple rectification, after the propylene oxide purity reaches more than 98%, the relative volatility of methyl alcohol and propylene oxide is close to 1, in order to further reduce the content of methanol needs very large reflux ...

AI Technical Summary

Problems solved by technology

[0009] In the above-mentioned methods, either the purification effect is not ideal, or only a single substance is separated, and satisfactory results cannot be achieved.