Process for preparing 1,3-propanediol by hydrogenation of high-concentration methyl 3-hydroxypropionate

Abstract

The invention relates to a process for preparing 1,3-propylene glycol (1,3-PDO) by means of hydrogenating high-concentration 3-methyl lactate (3-MHP). The process comprises the following flow: gasifying 3-MHP and H2 in a mixed manner, feeding the mixed gas into a first hydrogenation reactor, feeding a hydrogenation product into a gas-liquid separator to separate mixed gas of a heavy component I, hydrogen and a light component I; feeding the mixed gas into a first separating tank to separate H2 out for recycling, and feeding a retaining liquid phase into a first rectification tower for separating into a light component II and a heavy component II; feeding the heavy component II and the heavy component I into a second hydrogenation reactor for further hydrogenating, feeding a hydrogenation product into a second separating tank for separating H2 out for recycling, feeding remaining components into a second rectification tower into a light component III and crude 1,3-PDO, and refining the crude 1,3-PDO to obtain a 1,3-PDO product; separating the light component II from the light component III to obtain methyl alcohol and n-propyl alcohol. In the entire process, the high-concentration 3-MHP is used for hydrogenating, so that the energy consumption of solvent separation is lowered. Meanwhile, by two-segment hydrogenation is performed, the yield of the 1,3-PDO is increased.

Description

technical field [0001] The invention relates to a process for preparing 1,3-propanediol (1,3-PDO) by hydrogenating high-concentration methyl 3-hydroxypropionate (3-MHP), and belongs to the field of hydrogenation of esters to alcohols. Background technique [0002] 1,3-PDO is an important organic chemical raw material, and it can be polymerized with terephthalic acid to obtain PTT polyester with excellent performance and broad market prospects. The industrialized routes mainly include: (1) the ethylene oxide method of Shell Company of the United States, see patents US770776, US5723389, and US5777182; (2) the acrolein method of Degussa, see patents US6232511, US6140543, etc.; (3) the United States The biological method of DuPont Company, see patent EP361082, DE3734764 etc. The first two methods all need to use 3-hydroxypropanal as an intermediate, which is unstable and easily forms oligomers and acetals. It brings difficulties to the hydrogenation process within a certain ra...

AI Technical Summary

Problems solved by technology

However, in hydrogenation, in order to improve the performance of the catalyst, a large amount of methanol and high-boiling point organics are added to the raw material, which causes great difficulties to the subsequent separation and purification

In the example of David-Samsung, there is no result of high-concentration 3-MHP hydrogenation, and there are no related patents for the subsequent separation

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