Neural Network Aided Design Of Catalyst For Propane Ammoxidation

Acrylonitrile(ACN) is an important intermediate in organic polymerization. Nearly all of the ACN produced in the world today is produced by the Sohio process. Various recent changes in the petrochemical market have created two incentives for improving current acrylonitrile(ACN) technology based on propylene ammoxidation: I) the increase in the propylene prices provides the economic driving force to evaluate alternative lower cost feedstocks and ii) required new production capacities or substitution of old plants provides the opportunity to utilize new technology. The cost of propane feedstock is about 5-6 times less than the cost of propylene and thus the development of a process based on propane as the main material appears to be the more direct evolution of propylene ammoxidation process:C₃H₈+NH₃+O₂→CH₂CHCN + 4H₂O (H= -151.13kcal/mol)In recent years a large number of patents have been published. These patents involve mainly about the following catalytic systems V-P-Ox, Ga-Sb-Ox, VSb(W,Sn)Ox, Bi-Mo and bifunctional catalyst. But an review of these patents indicates the most promising one is VSb(W,Sn)Ox/SIAL catalyst.The kinetics of the direct synthesis of ACN from propane on VSb(W,Sn)Ox /SIAL mixed oxides indicate that ACN forms through two parallel pathways, one directly from propane and the second, which is the prevalent path, through the intermediate fonnation of propylene. The limiting factor in the formation of ACN is the relative slowness of the step of allylic oxidation to ACN of the intermediate propylene, and the high rate of propylene oxidation to carbon oxides. The active phase in the catalyst is VSbO₄ and α - Sb₂O₄. In literatures the best yield of ACN is about 40%. Some improvements of the catalyst is needed to increase the yield of ACN.Catalyst design largely depends on empirical and qualitative knowledges, rather than on theoretical and quantitative relationships. Therefore, artificial...