III International Conference

PP-II-123The analysis of the hydrocarbons C 5+ formed in the presence of zeolites Beta and TsVN(Si/Al ratio is 32) showed that their fractional compositions did not correspond to themolecular-mass distribution typical for products of classical Fischer–Tropsch polymerization.In these cases molecular-mass distribution had maximum at C 9 –C 14 hydrocarbons. In othercases fractional compositions corresponded well to molecular-mass distribution ofpolymerization processes. This phenomenon can be explained by heavier aluminum presencein zeolites Beta and TsVN (Si/Al ratios are 40 and 32 respectively). Shift of synthesisproducts to the area of heavier hydrocarbons can be successfully explained by olefinsformation in the result of hydrocracking of polymerization products over the acid centers.These olefins can be oligomerizated, or create additional centers of chain growth.Comparison of group compositions of hydrocarbons produced over Co-Beta andCo-ZSM-12 catalysts showed that C 5+ isoparaffines content was two times higher over Co-Beta, than over Co-ZSM-12, while C 5+ olefins and n-paraffines were 2–3.5 less abundant overCo-Beta, than over Co-ZSM-12. That clarifies the contribution of acid centers.391