Study On Catalytic Process Of1,3-Butadiene Formation From Ethanol

1,3-Butadiene has many uses in industry, which is used to create synthetic rubber,and butadiene is also a feedstock for numerous plastic products. Butadiene in theworld is mainly extracted from the C4fraction in the by-product of naphtha crackingto ethylene. Although this method is high purity and low cost, the development islimited by oil resources. With the development of bioethanol, it is valuable to producebutadiene from ethanol. In this work, the preparation of MgO/SiO₂catalyst, operationconditions and process of ethanol to butadiene were studied. The main results were asfollows:The research studied the preparation method, calcined temperature and MgOcontent of the MgO/SiO₂catalyst, while the structure and acidic-basic properties ofthe catalysts were characterized by X-ray diffraction （XRD）, temperatureprogrammed desorption （TPD） and transmission electron microscopy （TEM）. Theresults showed that the preparation method of wet-kneading was better; and the bestcalcined temperature was773K; and when MgO content was80wt%, the catalyst hadthe highest selectivity.The optimized reaction conditions were as follows: reaction temperature was693K, the W.H.S.V was1.8h-1, concentration of ethanol in the feed was95%, theethanol conversion was67%and the butadiene selectivity could be52%.The study on the formation process of butadiene showed that the process ofethanol to butadiene was as follows: firstly, ethanol is dehydrogenated to formacetaldehyde; a coupling of acetaldehyde forms acetaldol, and then dehydrated toform croton aldehyde. Then ethanol is involved a second time in a hydrogen transferreaction with croton aldehyde. Finally, croton aldehyde was dehydrated to formbutadiene.