Method for synchronously preparing biodiesel and glycerol carbonate by using alkali-earth oxide as catalyst

Abstract

The invention relates to a method for synchronously preparing biodiesel and glycerol carbonate by using alkali-earth oxide as a catalyst, which comprises the following steps: adding natural grease, dimethyl carbonate and methanol into a reaction kettle, adding solid alkali powder into the reaction kettle while stirring, heating while stirring, cooling to room temperature, filtering the reaction product, and washing with dimethyl carbonate until the filter residue is white, thereby obtaining a filtrate; evaporating the filtrate to remove excessive dimethyl carbonate and methanol under reduced pressure to obtain a light yellow liquid which is a biodiesel crude product; extracting the biodiesel crude product with equal volume of methanol 2-4 times, wherein the residue is purified biodiesel; and merging the methanol solutions, and evaporating to remove methanol to obtain the glycerol carbonate. The calcium oxide used as the catalyst has the advantages of low price and high catalytic activity; the calcium oxide has lower solubility in organic solvents than other alkaline catalysts, and thus, can be easily removed by filtration separation after reaction; and thus, the invention has the advantages of lower technical difficulty and lower processing cost.

Description

technical field [0001] The invention relates to the technical field of biodiesel preparation, in particular to a method for synchronously preparing biodiesel and glycerol carbonate catalyzed by alkaline earth metal oxides. Background technique [0002] At present, my country's diesel consumption is about 90 million tons per year, largely dependent on imports. It is estimated that my country's diesel demand in 2012 will exceed 100 million tons. The sales price of biodiesel is about 5,000 yuan / ton. If the mixing ratio of diesel and biodiesel is 80:20 (that is, the B20 standard), the annual demand for biodiesel in my country is 18 million tons, and the total potential market is 90 billion yuan. . At present, my country's actual output has not exceeded 1 million tons per year. According to the national plan, it will reach 15 million tons by 2020. [0003] The in-depth development of glycerol, a by-product of the biodiesel industry, is also an important factor in promoting the ...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the above-mentioned shortcoming of the prior art, the object of the present invention is to provide the method for the simultaneous preparation of biodiesel and glycerol carbonate by solid base catalysis, and convert glycerol into carbonate while preparing biodiesel, which can solve the problem of traditional biodiesel production. Glycerin residue problem, and high value-added glycerol carbonate can be obtained at the same time. The catalyst used has strong alkalinity and high catalytic efficiency. At the same time, it has low solubility in the reaction system and is not easy to saponify with raw materials and products. Improvement, so that multiple steps such as separation and deep processing of biodiesel and its by-products are highly integrated, which is conducive to upgrading the biodiesel preparation process and improving the economic benefits of the biodiesel industry