Method for catalyzing hydrodeoxygenation of guaiacol to prepare cyclohexanol

Abstract

The invention discloses a method for catalyzing hydrodeoxygenation of guaiacol to prepare cyclohexanol. According to the method, the cyclohexanol is prepared through a one-step hydrogenolysis method,in which decalin liquor of guaiacol is catalyzed through supported catalyst x percent-Ru-y percent-MnO / g-CNTs; the catalyst takes multiwalled carbon nanotube subjected to mixed acid treatment as a carrier, and is formed by loading Ru-MnO on the carrier; in neutral liquid phase, guaiacol is subjected to one-step hydrogenolysis to produce cyclohexanol; the maximum selectivity of principal product cyclohexanol can reach 85.84 percent; the percent conversion reaches 99.38 percent, that is, the yield reaches 85.31 percent. The method has the advantages that the process route is simple, reaction equipment and operation method are simple, the reaction condition is mild, the reaction time is short, the catalyst is simple and available, the cost is low, the stability is good, products are pure, separation and extraction are easy, the expected economic benefit is very noticeable, and the method has great significance when being applied to industrial production.

Description

technical field [0001] The invention relates to the preparation of cyclohexanol, in particular to an acid-modified carbon nanotube loaded Ru and MnO bimetallic catalyst and a method for catalyzing the direct hydrogenolysis of guaiacol to generate cyclohexanol in one step. Background technique [0002] The survival of human beings is inseparable from energy, and the exploration of new energy sources for sustainable development has always been the focus and focus of the scientific community. Biomass energy, as a sustainable green energy, has been favored by scientific researchers in recent years. Plants contain a large amount of lignin, and the degradation of lignin can produce a large amount of alcohols or phenols, which can alleviate the pressure of non-renewable fossil energy, and has great research value. As a kind of lignin degradation product, the content of guaiacol is as high as 60%, and it is typical. Because the molecule contains not only benzene ring, phenolic hyd...

AI Technical Summary

Problems solved by technology

In the decahydronaphthalene solution with a mass fraction of 1% guaiacol, the reaction temperature is 120°C, and the hydrogen pressure is 2.0MPa. After continuous reaction for 2 hours, the conversion rate of reactants and the selectivity of cyclohexanol reach 100. %, and this high selectivity is attributed to the unique pore structure of the core-shell. Although this result is superior, the mass fraction of guaiacol used is only 1%, and the concentration is very low, so as to use a large amount of solvent At the expense of decahydronaphthalene, it has a great dependence on the amount of solvent. If the mass fraction of guaiacol is kept extremely low in each experiment, a large amount of solvent will be wasted, and the industrialization cost of this technology will increase sharply. Therefore, even if it can be The ideal selectivity is obtained, but the cost of separating the product is very high. Even if the selectivity of cyclohexanol is stably maintained at 100%, the content of the product cyclohexanol in the reaction solution is still extremely low (about 1%) , which hinders further separation and collection, and the processing cost is more likely to be higher than the purification of products with low purity, so the economic benefit is not ideal

In 2016, Professor Boonyasuwat (Catal Letter, 2013, 143:783-791) of the United States and Professor Ishikawa (Applied Catalysis B: Environmental, 2016, 182:193-203) of Japan both proposed to target the moderate concentration (10%~40%) ) hydrogenation experiment of guaiacol is the most suitable catalytically active metal is Ru instead of Ni, and the by-products are inevitable, so far the highest yield of its improved technology has not been able to break through 76%

Xu Xiwei from South China Agricultural University [CN 105461498A] invented a Fe-Ni bimetallic catalyst loaded on a molecular sieve for the gas-phase hydrogenation experiment of guaiacol on a fixed bed, at normal pressure and temperature between 250 and 400 °C The total yield of the product BTX (benzene, toluene, xylene) can reach 19.83%. This method reduces the loss of carbon atoms and the consumption of hydrogen, but the yield is too low and the required reaction temperature is too high

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