Study On Catalytic Performance Of Gold Catalyst For Selective Oxidation Of Ethanol

Ethyl Acetate, abbreviated as EA, is a kind of environmentally friendly industrial solvent, at the same time, it is also one of the synthetic flavor of edible spices. At present, the process of producing ethyl acetate, which is more mature in China, is acetic acid esterification method, but the catalyst used in this process which is highly corrosive is the concentrated sulfuric acid, and makes the equipment corrosion become more serious with the problems such as large environmental pollution and late treatment difficulties. On the contrary, the dehydrogenation of ethanoi with the development of new catalyst as the core, can be completed by using ethanoi as the only raw material, and the production of ethanol can be produced by the fermentation of crops, which isn’t entirely dependent on the non-renewable resources. Therefore, if a stable and efficient catalyst can be developed for promoting the industrialized production of the ethanol dehydrogenation reaction, the competitive position of the method of ethanol dehydrogenation in the production of ethyl acetate would be greatly increased.The work of this paper takes the layered double hydroxide (abbreviated as LDHs) of artificial synthesis and the Na montmorillonite (abbreviated as NaMMT) which is from the natural bentonite modified by purifying sodium as the carriers, using the prior research of the gold catalyst preparation method, obtained many gold catalysts supported on different kinds of layered supports, and the catalysts were used to catalyze the liquid phase oxidation of ethanol for the first time. This paper studies the effect of various factors on the catalytic activity, such as the type of carrier, the loading amount of gold, the amount of catalyst, the calcination temperature, the reaction conditions of ethanol liquid phase reaction (reaction temperature, reaction pressure, reaction time) and so on effect on catalytic activity.The research results show that:(1)According to the theoretical load of gold 2wt%, the gold nanoparticles are loaded on the LDHs carrier and NaMMT carrier to prepare the Au catalyst. The catalytic performances of the ethanol oxidation reaction in the liquid phase system are different.The NaMMT supported catalyst haven’t active. But the LDHs supported gold catalysts with three kinds of laminates have higher activity.(2)Used the 2wt%Au-MgAl-LDHs catalyst, which is prepared by supported the gold sol on LDHs, analyse the reaction optimized conditions (reaction temperature, reaction pressure and reaction time) through the single factor experiment and multi factor response surface methodology.The optimal reaction condition parameters which is obtained is that the reaction temperature is 128℃, the reaction pressure is 5 MPa and the reaction time is 7h. Under the optimum reaction conditions, the conversion rate of ethanol is 58%, and the selectivity of ethyl acetate is 87%.(3) The 2wt%Au-MgAl-LDHs catalyst still has high activity after repeated use.At the reaction condition of 128℃,5Mpa and 7h, when the catalyst has been used 4 times, its activity still can be 50% of the ethanol’s conversion rate, and 86% of selectivity of ethyl acetate,which shows that the catalyst has good stability in the selective oxidation system of the ethanol liquid phase.