Home – Home – Jornals – Chemistry for Sustainable Development 2023 number 2

New methods of zeolite HZSM-5 modification with bismuth compounds are proposed. The choice of bismuth as a modifying agent is due to the systematisation and generalisation of the available literature data and experimental results of studying the chemistry and synthesis of bismuth compounds of various compositions. Phases in the resulting bismuth-containing zeolite systems were identified by X-ray phase analysis, and the state of bismuth in chemical compounds was determined. The number and strength of acid sites in the original and modified samples were determined by the method of temperature-programmed desorption of ammonia. The catalytic activity of zeolites was studied in the process of hydrogen-free processing of straight-run gasoline fraction of oil into high-octane gasolines. The effect of modification methods and process temperature on the structural-group hydrocarbon composition, the yield of gaseous and liquid reaction products was studied, and the octane numbers of the resulting gasolines were determined. It is shown that over the bismuth-containing zeolite catalysts, in comparison with unmodified zeolite, the yield of the target product, high-octane gasoline containing a smaller amount of aromatic hydrocarbons, increases, which makes it more environmentally friendly. It has been established that the production of high-octane gasolines that meet modern requirements for motor fuels is possible over modified zeolites within a wider process temperature range. Based on the studies performed, Methods for modifying the HZSM-5 zeolite with bismuth are proposed on the basis of the studies performed. The proposed methods make it possible to improve the efficiency of the catalyst in the process of upgrading the straight-run gasoline fraction of oil.