Method for producing polymer grade ethylene glycol and co-producing methyl glycolate

Abstract

The invention discloses a method for producing polymer grade ethylene glycol and co-producing methyl glycolate, which comprises the following steps that: feed gas produced by taking coal, natural gas or residual oil as a raw material is subjected to purification treatment to obtain carbon monoxide and hydrogen through pressure varying absorption; the carbon monoxide, the hydrogen and auxiliary raw materials, namely industrial methanol, oxygen and nitrogen oxide are subjected to processes such as nitrosation reaction, carbonylation reaction, hydrogenation reaction, rectification separation, tail gas purification treatment and the like to obtain the ethylene glycol and the methyl glycolate; and the yield proportion of the ethylene glycol and the glycollic acid can be adjusted by controlling the hydrogenation reaction and the rectification process. In the method, the carbonylation reaction is performed on a Pd / alpha-Al2O3 catalyst added with two additives, and the carbonylation reaction is performed on a Cu-SiO2 or Cu-Cr2O3 or Cu-Zn-Al methanol catalyst, wherein the conversion ratio of the CO and the H2 is over 99.9 percent; and the selectivity is over 98 percent. Compared with the prior method for producing the ethylene glycol and the methyl glycolate, the method has the characteristics of low cost and high benefit.

Description

technical field [0001] The invention relates to a large-scale production of CO and H using coal, natural gas or residual oil as raw materials. 2 Process for the production of ethylene glycol (EG) and methyl glycolate (MG) from synthesis gas. Background technique [0002] Ethylene glycol is an important chemical industry raw material, widely used in the synthesis of polyester, surfactants, antifreeze and explosives, etc. The world consumes 20 million tons of ethylene glycol every year, which is the second largest synthetic product after methanol Alcohols. Methyl glycolate is an important fine chemical product used in the production of glycolic acid, etc. At present, the production method of ethylene glycol mainly adopts the oxidation of ethylene to ethylene oxide, and then hydrolyzes ethylene oxide to obtain an aqueous solution of ethylene glycol, and then obtains ethylene glycol through rectification. This method has a large consumption of raw materials and high energy con...

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Problems solved by technology

[0013] 1. Most of the currently disclosed methods are patents related to the synthesis of dimethyl oxalate, and the hydrogenation of dimethyl oxalate to ethylene glycol has not been considered. At the same time, most of the patents for the hydrogenation of dimethyl oxalate are catalyst patents

[0014] 2. Some patents have systematically disclosed processes such as raw material gas purification, methyl nitrite generation cycle, and dimethyl oxalate synthesis. The raw material gas purification uses ZnO desulfurizer, and the index is export total sulfur -6 (v / v), this relative noble metal catalyst requires total sulfur -6 As far as (v / v) is concerned, its sulfur content seriously exceeds the standard, which will inevitably poison the catalyst and shorten its life; H in high-content CO gas 2 Catalyzed removal using catalysts loaded with platinum group metals, but the selectivity of the catalyst was not mentioned, and CO and O were not mentioned 2 The CO raw material loss caused by the side reaction

[0015] 3. Another patent discloses a method for synthesizing dimethyl oxalate and producing dimethyl carbonate as a by-product. The selectivity of the synthetic catalyst fails to reach more than 99%, which increases the difficulty of product separation and purification

[0016] 4. The technical route of producing ethylene glycol through dimethyl oxalate, its actual application value depends on whether the product ethylene glycol can reach the polymerization grade, which is not mentioned in the current published methods and literatures

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