Modified Cu/Zno-Al₂O₃ Catalyst Of Methanol And Carbon Dioxide Synthesis Of Dimethyl Carbonate

Dimethyl carbonate?DMC? is able to replace phosgene and becomes an important "green chemicals." Since it belongs to the green chemical raw material, so it attracts more and more attention, especially in recent years, especially DMC can be used as an additive for gasoline and diesel oil. Dimethyl carbonate?DMC? is an environmentally friendly organic synthesis intermediates, it can instead of dimethyl sulfate, methyl chloride and other toxic chemicals as methylating reagent, can also be used as carbonyl reagents instead of phosgene. In addition, DMC was added to the gasoline, not only improved the fuel octane number, but also reduced the waste gas pollution. CO₂ is one of the main gases that cause global greenhouse effect, and is also a potential carbon resource. Using CO₂ and CH3 OH as raw materials to synthesize two methyl carbonate?DMC? with double meanings of green chemistry and resource recycling. In this paper, the DMC reaction of the gas solid phase CO₂ and the direct synthesis of methanol was studied.1.La2O3-ZrO₂ is added to the Cu/ZnO-Al₂O₃, by co-precipitation method and potassium borohydride reduction to prepare the catalyst for a series of different flow ratio and to which joined HZSM5 molecular sieve, at the same time, explore maximum enhancement La2O3-ZrO₂ ratio of catalyst activity, and the use of XRD, TPD, BET on the catalyst structure were characterized. Through the characterization and testing, the optimum reaction conditions for direct synthesis of DMC from methanol and CO₂ were confirmed. The experimental results are as follows: in the case of all the addition of HZSM5, the catalyst showed the best activity when the ratio of La2O3-ZrO₂ was 2:1. At this time, the conversion of methanol can reach 8.99%, and the selectivity of DMC is 88.33%.2.Cu/ZnO-Al₂O₃-La2O3-ZrO₂ zeolite?HZSM5, HMCM56, HMCM22? were prepared by co-precipitation method in this study. Through the comparison of different catalysts, it was found that the catalytic activity of Cu/ZnO-Al₂O₃/La2O3-ZrO₂/HZSM-5 was the best of these three catalysts. To Cu/ZnO-Al₂O₃/La2O3-ZrO₂/HZSM-5 as catalyst, through the optimization of reaction conditions, determine the optimum reaction conditions are as follows: the reaction temperature is 503 K, carbon dioxide and methanol material ratio of 2:1, catalyst dosage was 1.0 g, reaction pressure was 1.0MPa. Under the reaction conditions, the conversion rate of methanol can reach 8.99%, and the selectivity of DMC is 88.33%.