Study On Direct Synthesis Of Ethyl Acetate From Ethanol Over Mo-Based Catalyst

Among the different technical routes for ethyl acetate production, the direct synthesis from ethanol has drawn more and more attention because of its less corrosion, low toxicity and cost.In this work, the novel MoS₂/C supported catalyst and the related technology for one-step synthesis of ethyl acetate from ethanol were developed. The promoter effect of Cu on the performance of catalyst was investigated. The technological conditions were optimized and the possible reaction mechanism was discussed.The results showed that the addition of Cu could improve the selectivity of ethyl acetate (EA) and inhabited the formation of acetaldehyde. When the Cu loading was 5% based on the MoS₂ weight, the selectivity for EA could reach to 48%. The adding sequences of promoter may also influence the catalytic properties. The prior addition of Cu could enhance the activity. The XRD characteristic of the catalyst showed that the new Cu-Mo-S phase with molar ratio of 0.67:6:9.15 was formed. Under the optimized reaction conditions of temperature 290℃and ethanol space velocity 0.6h^-1, the ethanol conversion was 86% and EA selectivity was 48%.The study on the formation mechanism of EA showed that there was two steps dehydrogenation in the reaction. The first step was ethanol dehydrogenation to acetaldehyde, and the second one was the addition-dehydrogenation of ethanol with acetaldehyde to EA. Starting from acetaldehyde alone, EA could not be formed on this catalyst, which denied the EA formation mechanism via condensation and disproportionation of acetaldehyde. The major byproducts ethylene and propylene were converted from ethanol, but difficultly from the conversion of acetaldehyde.