Method for preparing ethylene glycol and 1,2-propylene glycol by carrying out selective hydrogenolysis on high-carbon polyalcohol

Abstract

The invention discloses a method for preparing ethylene glycol and 1,2-propylene glycol by carrying out selective hydrogenolysis on high-carbon polyalcohol. According to the method, xylitol or sorbitol is used as a raw materials, water is used as a solvent, and a reaction is performed for 1 to 8h at a temperature of 140 to 220 DEG C, under H2 pressure of 2 to 10MPa and under a condition that an alkali additive and a catalyst exist; the catalyst uses CuM alloy as an active phase, and copper content is 10 to 85wt%; M is one or two of Fe, Co, Ni, W and Mo, and has content of 2 to 20wt%; a carrier is one of silicon dioxide, aluminium oxide, HZSM5 and SBA-15, and has content of 10 to 70wt%. According to the method disclosed by the invention,poison element Cr and heavy metal are not involved, and high hydrogenolysis activity, high target dihydric alcohol selectivity and recycling stability for the high-carbon polyalcohol are achieved under a mild condition.

Description

technical field [0001] The invention relates to a method for preparing ethylene glycol and 1,2-propanediol by selective hydrogenolysis of high-carbon polyols. Background technique [0002] Ethylene glycol (EG) and 1,2-propanediol (1,2-PDO) are widely used bulk chemicals, mainly used as key monomer raw materials for the synthesis of unsaturated polyesters, and are also important organic solvents and synthetic intermediates body. Ethylene glycol can also be used as antifreeze, lubricant, plasticizer, nonionic surfactant, brake fluid, ink and photographic microfluidics, etc. 1,2-Propanediol is also used in the production of surfactants, plasticizers, emulsifiers and demulsifiers, etc. Because of its safety and low toxicity, it is widely used as hygroscopic agent, antifreeze agent, lubricant and antifungal agent in food, medicine and cosmetics industries. At present, ethylene glycol and 1,2-propanediol are mainly produced by the hydration route of ethylene oxide and propylene...

AI Technical Summary

Problems solved by technology

Chinese patent 101628852A discloses that Ru alloy catalyst can be used at 20 MPa H 2 Hydrolysis of xylitol under pressure at 260 °C yielded 28.4% and 47.6% selectivity to ethylene glycol and 1,2-propanediol, respectively, but no conversion or yield was reported

It should also be pointed out that Ru and Pd are noble metals, and their catalyst costs are relatively high, which is not conducive to large-scale industrial application.

[0004] Recently, Chinese patent CN 102731259A discloses the application of a Cu-based supported catalyst in the process of selective hydrogenolysis of xylitol and sorbitol to prepare 1,2-propanediol and ethylene glycol, although the catalyst can significantly suppress unnecessary C-C bond cleavage The generation of by-products such as methane, but because the catalyst uses metal Cu as the active phase, its hydrogenation activity is not high enough, and a large amount of by-products such as lactic acid and glycolic acid are generated during the reaction process (selectivity up to 20-30%), resulting in ethylene glycol and 1 , the total yield of 2-propanediol is only 50-60%

In addition, due to the sintering of active Cu and the serious carbon deposition on the surface of the catalyst during the reaction, the stability of the catalyst is not good.

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