Catalytic Synthesis Of N-Butanol From Ethanol By Calcium Based Catalyst

N-butanol is an important chemical raw material and widely used in chemical, pharmaceutical, food and other fields, such as butyl acrylate, ethyl acetate, medicine and perfume extraction agent, printing ink dewaxing agent and solvent. In addition, n-butanol has high energy density, strong antiknock and show a huge market potential in the application of green renewable energy. The industrial production methods of n-butanol in the world mainly include fermentation, oxo-synthesis and aldehyde condensation which have some disadvantages such as large amount of raw material consumption, serious pollution, complex process route and difficult separation of products. However, the synthesis of butanol from ethanol, because of its advantages of little pollution, high atomic utilization rate and simple synthesis process, has attracted extensive interest. At present, the research about ethanol to n-butanol is mainly focused on the catalyst and synthesis mechanism. Generally, the catalysts in the literature include Mg/Al oxide catalysts, HAP catalysts and zeolite catalysts and the main synthetic mechanisms proposed are Guerbet mechanism and ?-H synthesis path. However, the yield of n-butanol is less than 20%.In the research of "calcium carbide and alcohol", the by-product n-butanol was found in the reaction of calcium carbide and ethanol. Through the characterization and analysis of solid products, the solid product is found to contain calcium ethoxide. Soybean oil and rapeseed oil has been used for the synthesis of biodiesel under ethanol calcium as a solid base catalyst. In order to expand the application of calcium based catalyst in the synthesis of n-butanol from ethanol and further improve the yield of n-butanol. In order to enrich the understanding of the reaction of calcium carbide and alcohol in the laboratory, this paper studies the reaction system of ethanol to n-butanol using calcium ethanol as catalyst. The experiments selected different types of calcium compounds with ethanol, compared and analyzed the product, studied condensation mechanism as well as main influence factor of ethanol to n-butanol. The results of this study show that:(1) Abundance of acid and alkali active sites on calcium based catalysts is key factor for the yield of n-butanol which means acid site catalyze dehydration of ethanol to ethylene, facilitates the synthesis of n-butanol and alkaline site catalyze dehydrogenation of ethanol and condensation of acetaldehyde, not facilitates the synthesis of n-butanol.(2) It can be concluded that the reaction path of calcium ethoxide with ethanol is related to the reaction temperature. In low-temperature stage (270-330'C), the reaction path follow the mechanism of Guerbet, namely ethanol dehydration into aldehyde and aldehyde condensation and hydrogenation. In the high temperature stage (330-390?), the main reaction path is uncertainty, but aldol condensation path is not the dominant mechanism which can be confirmed.(3) For the role of Ca2+, it was found that the metal ions have no the obvious function for the reaction of ethanol to n-butanol by the comparison between different ethoxide with ethanol.