Study On Preparation And Catalytic Performance Of MgO-Ta-SiO₂ Catalysts For The Conversion Of Ethanol To 1,3-Butadiene

1,3-Butadiene is an important raw material in chemical industry and is widely used in the production of polybutadiene,synthetic rubber,ABS rubber and other industrial products.At present,the main sources of 1,3-butadiene in industry are the by-products of petroleum to ethylene route,and the dehydrogenation of C4 by-products such as butene and butane.In recent years,due to economic and environmental costs of petroleum and the increased awareness of environmental protection,there is an urgent need to develop an environmentally friendly and sustainable 1,3-butadiene production route.The increasing maturity of bio-ethanol technology has made the ethanol to 1,3-butadiene route,once again obtained the attentions.And the development of catalysts for the ethanol to 1,3-butadiene route has become one of the hot topics.In this work,MgO-SiO₂ and MgO-Ta-SiO₂ catalyst with Ta loading was prepared via impregnation method with silica gel as carrier,and the influence of preparation conditions on catalyst structure and performance was investigated.The influence of reaction conditions like WHSV,reaction temperature,ethanol to acetaldehyde molar ratio in feed on the performance of MgO-Ta-SiO₂ catalyst was studied.On the basis,the stability of MgO-Ta-SiO₂ catalyst was investigated.Experimental research showed that for the MgO-SiO₂ catalyst prepared with impregnation method,Mg O was dispersed well on the carrier.A certain amount of Mg-O-Si structures could be formed,which provided the reaction sites for MPV reaction and aldol condensation reaction.MgO-Ta-SiO₂ catalyst combined the advantages of MgO-SiO₂ and Ta-Si O₂ catalysts,and showed better catalytic activity because of the suitable acid-base properties.The suitable acid sites promoted the MPV reaction,while inhibiting the dehydration side reaction of ethanol.The appropriate basic sites not only promoted the aldol condensation process,but also inhibited the excessive condensation of acetaldehyde to generate excessive heavy components.The reaction conditions of ethanol to 1,3-butadiene reaction performed on MgO-Ta-SiO₂ catalyst were optimized.Under optimal reaction conditions,the total conversion was 41.34%,and the selectivity of the target product 1,3-butadiene was 72.56%.The catalytic stability of MgO-Ta-SiO₂catalyst was investigated in a 100 h-long-term activity evaluation,the results showed that the catalyst had good stability.