Theoretical Aspects of the Reaction of Ethanol and Dimethyl Ether Conversion to 1,3-Butadiene

Resumo

In the synthesis of 1,3-butadiene from dimethyl ether (DME) on a Zn-Al₂O₃ catalyst, it has been found that the yield of the target product is 20% lower relative to the conversion of ethanol. However, the results of thermodynamic calculations showed an equal probability of the conversion of ethanol and DME and the same temperature dependence of the equilibrium composition of the reaction products. Using calculation by the quantum-chemical method of density functional theory DFT B3LYP/6-31(d), it has been established that dehydration and dehydrogenation of DME proceeds with a lower activation energy. The interaction of ethanol and DME molecules with the Zn₄O₄ cluster has been considered. It has been shown that interacting with zinc oxide, the ethanol molecule is to a greater extent subject to degradation due to the polarity of the OH bond in the molecule. It has been found that the catalytic system based on zinc oxide is not sufficiently active to ensure the effective reaction of DME conversion to 1,3-butadiene, unlike the case of ethanol.