Tag Archives: zeolite
In nowadays the chemical composition of modern motor fuels must be tightly regulated. This trend motivate the development of the process of sulfuric acid alkylation, which aimed at obtaining a high-octane components of gasoline – alkylate.
The catalyst for getting alkylbenzene is sulfuric of hydrofluoric acid. By the using these acids, we can get the production of high quality alkylate, with good selectivity and yield. But a significant disadvantage of liquid homogeneous catalysts is their corrosive activity and aggressiveness. These acids can be the reason of corrosion, equipment spoiling, leaks and humans burns.
This article describe the analysis of analytical systems (ionic liquids and zeolites), which can replace traditional homogeneous catalyst. Solid catalytic systems and ionic liquids are increasing yield, quality and safety at the workplace, because they don`t have liquid aggressive catalyst`s disadvantages.
The paper considers the potential dangers of sulfuric acid alkylation process and their impact on the life and health of personnel. This article considers the technological scheme of sulfuric acid alkylation process and the chemistry of the main reaction of getting alkylate. Methods for improving the safety of operation of the installation are proposed.
An analysis of pros and cons is made for heterogeneous catalysts and ionic liquids, which are an alternative substitute for sulfuric acid. The technological scheme of the alkylation process is described in the case of using solid catalysts.
This paper is dedicated to synthesis of MOR-type zeolite specimens in Na- and H-form of high phase purity and having crystallinity degree of nearly 100% with molar ratio of SiO2/Al2O3 = 15-24 in deep-decationated form, and investigation of their properties. To obtain chemically homogeneous silica-alumina hydrogel, mixing of crystal-forming components was implemented with reaction mass being continuously stirred. The stirring was still continuing during the process of crystallization. Crystallization was conducted at a temperature of 150-160 ºС. The compositions of oligomers were quantified by high-performance liquid chromatography. The conversion of the initial olefin, its composition and amount of its isomers, the amount of low molecular weight oligomers (with a molecular weight less than the dimers) as well as the number of dimer were measured by gas-liquid chromatography. The dimer fraction was extracted by reaction mixture distillation under reduced pressure and analyzed by nuclear magnetic resonance (NMR) ¹H, ¹³C, IR- and mass spectrometry methods. By method of temperature-programmed ammonia desorption it was found that with zeolite module increasing there was an increase in strength of zeolite acid sites. For evaluation of catalytic properties of the derived H-form of MOR-type zeolite specimens with various modules, model reaction of a-methylstyrene dimerization was used. It was found that with zeolite module increasing there was an increase in cyclic dimers formation selectivity from 20 to 52%. The α-methylstyrene conversions on MOR-type zeolite specimens were investigated at a temperature of 80 ºС with a 10% catalyst in nitrogen atmosphere. The catalyst was calcinated prior to the reaction at a temperature of 300 ºС during 2-3 hours with rare gas current in the reaction flask. Implementation of the method developed makes it possible to expand the raw materials base, simplify the synthesis and reduce the cost of powdery mordenite type zeolite.
For the first time the synthesis method of powdery mordenite type zeolite based on crystallization of metakaolin in sodium silicate solution at temperature 150 °C for 14 hours is developed. The zeolite having 100 % crystallinity degree crystallized from the reaction mixture (RM) with the composition 2,9Na2О • Аl2О3 • 12SiО2 • 300H2O. Previously 10 wt. % crystal seed was introduced in RM, crystallization was carried out under continuous stirring. Implementation of the developed method allows to extend the raw materials base, simplify the synthesis and reduce the cost of powdery mordenite type zeolite.