Solid-acid alkylation catalysts based on modified type Y zeolites in polycation-decationized forms

Abstract

Industrial procedures for the production of alkylate are associated with use of dangerous and toxic liquid catalysts. Developments are being made worldwide to convert the alkylation process to solid-acid catalysts. These catalysts are characterized, however, by a short service life. The potential for improvement in the operational properties of solid-acid catalysts by the introduction of small amounts of promoters to the reaction is examined.Throughout the world, the portion of alkylate in the overall consumption of components has reached 25% in automotive gasolines, and more than 60% in aviation gasolines. The volume of alkylate production exceeds 70 million tons/year abroad, and a total of 0.5 million tons/year in Russia. According to forecasts for the next several years, use of alkylate in the United States will double [1].The operational and ecological properties of alkylate satisfy requirements set forth in modern European and American standards for fuel utilized by automotive internal-combustion engines. Industrial procedures for its production are associated with use of such dangerous and toxic liquid catalysts as sulfuric or hydrofluoric acid, requiring use of equipment for neutralization of the acid, vessels for washing of the product, and tanks for storage of the fresh and spent acid. Hydrofluoric acid is again more dangerous by the fact that it is capable of forming stable aerosols during an emergency leakage. In this connection, the development of an alkylation procedure using catalysts devoid of deficiencies inherent to liquid acid catalysts is one of the promising problems. Some of these catalysts may become new heterogeneous catalysts that are developed on a zeolite base. Manifesting high selectivity, activity, stability, and capability of regeneration, which are required for successful alkylation [2], zeolites ensure the production of high-quality alkylate.Type NaY zeolites are inactive in the alkylation process. Only essentially complete ion exchange of Na + ions for NH 4 + , Ca 2+ , and RZ 3+ cations with intermediate stages of calcination at 570-600°C merely results in their manifestation of Lewis and Bronsted acid centers, which are required for the formation of

Characterisation of nanocrystalline sulfated titania modified with transition metals and aluminum as solid acids for esterification

“…www.prkm.co.uk Solid acids, and particularly solid superacids, can be used instead of conventional catalysts in organic transformations [2]. It has been observed that the solid superacids are useful catalysts for the isomerisation [3,4], alkylation [5][6][7], amidation [8], oligomerisation [9], esterification [10][11][12][13][14][15] and the hydrolysis of cellulose [16,17]. Different kinds of solid superacid have been developed: (i) mounted acids which were obtained by fixation of a liquid acid such as SbF 5 on supports with high surface area; (ii) combined acids which were obtained by the combination of aluminum halides with metal salts such as CuCl 2 or CuSO 4 ; (iii) sulfate-promoted metal oxides such as SO 4…”