Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia

CATALYTIC CONVERSION OF ETHANOL INTO BUTADIENEOrdomsky V.V., Sushkevich V.L., Ivanova I.I.Department of Chemistry, Moscow State University, Moscow, Russiaiiivanova@phys.chem.msu.ruPP-42Butadiene is a major product of the petrochemical industry and an importantbuilding block for many industrial products. The main applications of butadiene areconnected with production of synthetic rubbers. The traditional approach forbutadiene production (over 95%) based on extraction from heavy steam crackers.However, the increase of the cost of oil extraction force to search ways of butadieneproduction from the recovery resources like ethanol.The first process of butadiene production from ethanol (Lebedev process) wasdeveloped and commercialized in the Soviet Union in the 1930s. This processinvolved two steps: dehydrogenation of ethanol to acetaldehyde and conversion ofacetaldehyde into butadiene. The second step was carried out over basic catalystcontaining magnesium oxide. However, acetaldehyde conversion was 35 to 37% perpass and the maximum yield of butadiene was only 60 to 64%. In addition, the lifetime of the catalysts between regenerations was very short (1-2 days).In the present work different basic, acidic and acid-base catalytic systems werestudied in the synthesis of butadiene from ethanol. It was found out that the processcan be carried out in one step. Introduction of the metal such as copper to acid-basebifunctional catalyst was shown to give positive effect on the conversion of ethanoland selectivity in butadiene. Investigation of the reaction mechanism and active sitesshowed that first stage of the process can proceed via direct reaction of ethanol intocrotonaldehyde on metal-acid-base site pairs without the intermediate formation ofgas phase acetaldehyde. This leads to decrease of the rate of futher condensation ofcrotonaldehyde and formation of heavy products like in the case of two step process.The study of model reaction of crotonaldehyde with ethanol pointed that the reductionof crotonaldehyde intermediate product by alcohol proceeds via Meerwein–Pondorf–Verley (MPV) mechanism over the Lewis acid sites of the catalyst.The best catalytic performance was obtained over multifunctional catalyst whichallowed for the direct transformation of ethanol into butadiene with the conversion ofethanol 44%, the yield of butadiene of 84% and high stability of work at relatively lowtemperature (325°C).131