Method for preparing lactic acid through catalyzing glycerol by supported copper catalyst

Abstract

The invention relates to the technical field of lactic acid preparation and particularly relates to a method for preparing lactic acid through catalyzing glycerol by a supported copper catalyst. According to the method, the selectivity of lactic acid can reach 70-90%, and the conversion ratio of glycerol can reach 72-100%. The method is characterized in that reaction is carried out on glycerol which serves as a raw material in a high-pressure reactor under anaerobic and alkali source provided alkaline conditions in the presence of supported copper oxide which serves as a catalyst, thereby obtaining lactic acid, wherein a support of the supported copper oxide catalyst contains metal oxides, including MgO, ZrO2, TiO2, CeO2 and ZnO, activated charcoal or hydroxyapatite; the supported copper catalyst is easy to prepare, low in cost and relatively long in service life. The method has the advantages that the reaction temperature and reaction pressure are low, the catalyst activity is high, the selectivity is good, the reaction rate is high, and the process flow is safe and environmental-friendly and the like, so that the industrial prospect is good.

Description

technical field [0001] The invention relates to the technical field of lactic acid preparation, in particular to a method for preparing lactic acid from glycerin catalyzed by a supported copper catalyst. Background technique [0002] Lactic acid, the chemical system is named 2-hydroxypropanoic acid (2-Hydroxypropanoic acid). Since the carbon atom at the alpha position of the carboxyl group in the lactic acid molecule is an asymmetric carbon atom, lactic acid has two kinds of optical activity: left-handed (L-type) and The dextrorotatory (D-type) enantiomer; lactic acid was first discovered in yoghurt by Scheele in 1850, hence the name of lactic acid; lactic acid is one of the three recognized organic acids in the world, widely present in the human body, animals and The metabolism of microorganisms also exists in all aspects of people's lives. [0003] Lactic acid is an organic acid with a wide range of uses, mainly used in the food and pharmaceutical industries. In the brewi...

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Problems solved by technology

[0004]Glycerin is a by-product in the production of biodiesel. For every ten tons of biodiesel produced, one ton of glycerin is produced. With the increase of biodiesel production year by year, glycerin The output is also very large, using glycerin to produce a series of chemicals and chemical intermediates, with the characteristics of renewable and zero carbon dioxide emissions, and glycerin is rich in active hydroxyl groups, which can be easily replaced to synthesize special chemicals, so glycerin's Development and utilization have great prospects; recent studies have found that the use of glycerol to prepare lactic acid not only develops new uses of glycerin, but also provides a sustainable source of raw materials for lactic acid; it can be seen from literature reports that there are fermentation methods and chemical synthesis methods for the preparation of lactic acid from glycerol. Chemical synthesis methods include noble metal aerobic catalysis and high-temperature hydrothermal anaerobic oxidation; while fermentation and noble metal aerobic catalysis have the disadvantages of high cost, low glycerol reaction concentration and long reaction time; high-temperature hydrothermal anaerobic oxidation Higher requirements on reaction temperature and reaction pressure; Debdut Roy et al. used industrially produced Cu / SiO2, CuO / Al2O3 and Cu2O can effectively reduce the reaction temperature, but the reaction temperature, reaction time and lactic acid selectivity need to be improved