Catalysis and Petrochemistry最新文献

{"title":"New promising proton conducting electrolyte for high-temperature fuel cells based on hydrophobic guanidine salt","authors":"S. Rogalsky, O. Tarasyuk, V. Povazhnyi, T. Cherniavska, S. Makhno","doi":"10.15407/kataliz2021.32.086","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.086","url":null,"abstract":"Guanidine salts are promising proton conductors due to the high content of dissociable protons in guanidinium cation that ensure an efficient proton transfer along hydrogen-bonded network formed by proton donor and proton acceptor sites. However, the high melting point of most guanidine salts is a serious drawback for their application as proton conducting electrolytes. Reducing the symmetry of guanidinium cations by the substitution of hydrogen atoms on alkyl radicals reduces the melting points but also leads to decreased proton conductivity. In this study, monosubstituted guanidine salt, N-butylguanidinium bis(trifluoromethylsulfonyl)imide (BG-TFSI), has been synthesized by a simple two-step method. It is water immiscible room temperature protic ionic liquid. The structure of BG-TFSI was confirmed by nuclear magnetic resonance spectroscopy, as well as infrared spectroscopy. According to thermal gravimetric analysis data, the ionic liquid has the thermal degradation point (5% weight loss) of 348 °C which indicates its excellent thermal stability for use in high-temperature fuel cells. The ionic conductivity of BG-TFSI determined by the electrochemical impedance method was found to be 9·10-4 S/cm at room temperature. This value increased by almost one order of magnitude above 100 °C thus reaching an acceptable level for use in fuel cells. The activation energy Ea calculated from the Arrhenius plot for BG-TFSI is found to be 16.4 kJ/mol which is similar to those reported for other guanidine salts. Based on the obtained results one can assume that the proton transport in BG-TFSI is dominated by Grotthus-type (hopping) mechanism. The results of this study indicated that BG-TFSI is a promising proton conducting electrolyte for fuel cells operating at elevated temperatures in water-free conditions. The hydrophobicity of the ionic liquid is an important advantage since it can prevent its leaching from the polymer electrolyte membrane during the operation of a fuel cell.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85494798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of organic materials nature on petrol removal from water surfacee","authors":"I. Bacherikova, S. Grinenko, L. Kuznetsova, V. Zazhigalov, O.V. Bacherikov","doi":"10.15407/kataliz2021.31.075","DOIUrl":"https://doi.org/10.15407/kataliz2021.31.075","url":null,"abstract":"The properties of some organic materials in the removal of oil from water area were studied. It was shown that available materials as technical wool and sintepon can be used as effective sorbents for petroleum removal from water area. The sample mechanical wringing of these sorbents permits to return the part of adsorbed oil for its next use. The dependence of sorption properties (the adsorbed petroleum mass, specific oil adsorption, return of the oil and selectivity of petroleum removal) and petroleum removal from the number of absorption-release cycles was established. It was established that quantity of adsorbed oil decreases in other next step of removal but mass of oil returned increases in the process of mechanical wringing. The regeneration of these adsorbents by flushing in gasoline permits to obtained the initial properties in oil removal from water area. The sorption elements in the form of bags from linen with these materials were prepared. The dependence of the amount of oil removed by these sorption elements from the time of oil clearing of the water area process was determined and the optimal parameters of petroleum removal were established. It was shown that sorption elements on the base of these materials have adsorption capacity equal to 14-16 g of petroleum/g sorbent at selectivity of petroleum removal more than 70 % and oil recovery degree more than 80 % and the possibility their reusable use on oil spill response. The obtained positive results of oil removal from water area permit to propose in extreme cases of oil spills the available industrial products as jerseys, blankest, jackets etc. use successfully for petroleum spill response. The hydrophobization of these elements permits to improve their properties in oil removal from water area. As results of sorption elements modification the increase of adsorbed oil mass and specific petroleum removal at simultaneous increase of returned oil quantity for its next use and oil removal selectivity were established. It was established that synthesized sorption elements not inferior in properties known industrial sorbents for oil removal from water area.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77172940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of physico-chemical parameters of surface-active systems components for minimization of evaporation of hydrocarbon liquids","authors":"O. Spaska, AV.L. Chumak, M. Maksymyuk, V. Rudenko, O.I. Kosenko, E. V. Polunkin, O.O. Gaidai","doi":"10.15407/kataliz2021.31.084","DOIUrl":"https://doi.org/10.15407/kataliz2021.31.084","url":null,"abstract":"Highly efficient stable aerated hydrophilic compositions containing fluorotensides and ultralight microdisperse systems using gas-filled glass, aluminosilicate and polymer microspheres have been developed. Designing the compositions of PAS based on the surface activity of surfactants, their solubility in water and the ability to bind water and the formation of hydrogen bonds between the components. The main condition for the stability of the coating when mixing the components - the chemical interaction between them and the formation of a system that does not dissolve in hydrocarbons and does not break down in terms of use. The best film-forming characteristics necessary for the operation of the coating (simultaneous reduction of surface tension and film formation) active substances (FPAR), the non-polar part of the molecules of which contains a fluorocarbon chain, so they are insoluble in hydrocarbons, well soluble in water and easily distributed on the surface of hydrocarbon liquids, creating a protective film. The choice of co-surfactants was based on the ability to stabilize hydrophilic films on the surface of hydrocarbons not only at favorable HLB, but also at the lowest, although higher than the critical concentration of micelle formation (CCM), concentrations for forming a mixed adsorption layer of increased strength. This surfactant was water-oil-soluble twin-80, which will significantly increase the hydrophilic part and enhance the stability of the PAS and the stability of the aerated system. The introduction of glass microspheres into the components of the system has significantly enhanced its strength and stability. In the study of the stability and gas permeability of the developed surfactant systems, it was found that the insulating ability of the coating increases with increasing hydrophilic-lipophilic balance of the system and due to chemical interaction between the carboxyl group of fluorotenside and hydroxyl groups of surfactants.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"114 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79447181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alkaline synthesis of fatty acids iso-propyl esters","authors":"S. Zubenko, S. Konovalov, B.A. Denysiuk, L. Patrylak","doi":"10.15407/kataliz2021.32.032","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.032","url":null,"abstract":"Fatty acid alkyl esters are widely used products. Most of them are used as renewable transport fuel named “biodiesel”. Production of fatty acid iso-propyl esters mainly based on acid process, but using of alkaline catalysts may give good yields also. Alkaline catalysts have some advantageous such as low corrosivity and higher reaction rate. In current work the effectivity of potassium hydroxide and treated potassium hydroxide solution as catalyst for transesterification was compared. It was shown that using of KOH solution in iso-propyl alcohol after special treatment gives almost twice higher yields (95-96 %) from refined sunflower oil triglycerides than over KOH under the same conditions. Yield of fatty acids iso-propyl esters from wasted frying oil stabilized after 1-1.5 hours of reaction over both catalysts. Using 1.8 and 2.0 % treated catalyst at 90 °C leads to yield of about 86-88 % at 9:1 alcohol-to-oil ratio. Reaction temperature has significant impact on a yield wich decreases with temperature reduce in the range from 30 to 90 °C. During reaction proceeding the alkali saponification and thus loss the catalytic activity, which displayed in stopping the yield rising. The lower yield of esters from wasted oil comparing to the refined oil may be caused by presence of heavy polymerized triglycerides components formed during frying. Such components cannot be fully converted into monoalkylesters and gives also the oligomerized esters, which is not visible in standard gas chromatographic analysis of biodiesel. Indirect confirmation of the presence of such compounds in wasted frying oil sample is the sufficiently larger mass of the cube residue in vacuum distillation. For refined oil amount of such residue was only 5.4 %, while for wasted oil it was three time higher (14.9 %). In case of wasted frying oil as raw stuff, even after full conversion and effective self-separation conventional purification methods (like water washing or dry washing with adsorbents) may not provide the necessary purity of resulted biodiesel due to the presence of heavy oligomeric admixtures. In such cases vacuum distillation should be included as necessary final purification stage.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90453426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanochemystry as advanced methodology in green chemistry for applied catalysis","authors":"V. Zazhigalov, K. Wieczorek-Ciurowa, O. Sachuk, I. Bacherikova","doi":"10.15407/kataliz2021.31.001","DOIUrl":"https://doi.org/10.15407/kataliz2021.31.001","url":null,"abstract":"In this survey we have assessed how mechanochemistry techniques comply with the aims of Green Chemistry to minimise the use of environmentally damaging reactants and unwanted by-products. In the publications the preparation of vanadium-phosphorus oxides as industrial catalysts for maleic anhydride production from n-butane and perspective catalysts of phthalic anhydride manufacture by direct n-pentane oxidation were analyzed. It is shown that mechanochemical activation and synthesis reduces the amount of harmful waste used in the production of the catalyst and increases its effectiveness. Improvement of a catalyst’s properties, help limit production of harmful emissions such as carbon oxides and hydrocarbons. It was established that mechanochemical treatment can by successfully used in the process of industrial vanadium-phosphorus oxide catalysts modification or in the process of introduction in its composition of additives which lead to increase of activity and selectivity of hydrocarbons oxidation. The possibility of the mechanochemistry use in the vanadium-titanium oxide catalysts preparation which are the base catalysts in industrial phthalic anhydride production from o-xylene was determined. It was established that mechanochemical treatment of the vanadium and titanium oxides mixture permits to delete the nitrogen oxides emission in atmosphere and prepared catalysts demonstrate the same phthalic anhydride yield but at low reraction temperature. Catalysts, manufactured by mechanochemical treatment (on the base of molybdenum oxide), provide new techniques for producing compounds as exemplified by the direct oxidation of benzene to form phenol which can replace industrial two-step process from cumene or proposed process of benzene oxidation by N2O. Mechanochemistry treatment could produce catalysts which eliminated the need to use highly toxic nitrogen oxides as reducing agents. The article describes activating Cu-Ce-O catalysts which reduce the temperature of the process for removing carbon monoxide from exhaust gases and as a method for purifying hydrogen u sed in fuel cells. Finally, there is a description of mechanochemically treated catalysts, containing metals and supported on stainless steel supports which are used to remove aromatic hydrocarbons from water sewers.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77689141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fuel-grade sunflower oil butyl esters: synthesis, purification, oxidation stability","authors":"S. Konovalov, S. Zubenko, L. Patrylak, A. Yakovenko","doi":"10.15407/kataliz2021.32.040","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.040","url":null,"abstract":"Current paper deals with production, purification and oxidative stability enhancement of fuel-grade sunflower oil butyl esters as more ecological alternative of methyl esters as biodiesel. The oil feedstock, used in this study, included refined sunflower oil (acid value – 0.05 mg KOH/g; 25.3 % of oleic and 61.2 % of linoleic acids) and wasted frying high-oleic sunflower oil (acid value – 1.20 mg KOH/g; 6.1 % of linoleic and 81.7 % of oleic acids). Butanolysis was carried out using potassium butoxide, obtained from KOH and alcohols via original patent-pending method, under mild reaction conditions (alcohol-to-oil molar ratio – 4.5-5.0, 15°C, 1.4-1.6 %еq. KOH of butoxide, 20-30 min). High molar yield of butyl esters (93-96 %) was achieved, while glycerol and vast majority of alkaline catalyst formed the separate reaction products phase mainly in the course of reaction. Ester enriched phases were purified in order to obtain fuel-grade butanol-based biodiesel. Samples after removing of butanol under vacuum followed by water washing and drying were characterized by not enough high butyl esters content (about 94-95 %), as well as higher than allowed content of unconverted glycerides. Vacuum distillation as final purification step allowed fitting butyl esters samples composition within the requirements for biodiesel fuel. Distilled samples contained about 99 % of butyl esters, 0.4-0.5 % of monoglycerides and almost no n-butanol, glycerol, di- and triglycerides. Oxidative treatment (110°C, 6 h, air bubbling) revealed the high oxidation stability of the sample, originated from wasted high-oleic oil, due to the predominance of oleic acid in its fatty acid composition. The sample, obtained from refined sunflower oil (mainly linoleic acid in fatty acid composition), demonstrated very low stability. Addition of at least 2000 mg/kg of antioxidant 2,6-di-tert-butyl-4-methylphenol was shown to be able to improve this characteristic to the level of biodiesel requirements.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"170 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72887013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Active centers of redox catalysts","authors":"G. Kosmambetova","doi":"10.15407/kataliz2021.32.009","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.009","url":null,"abstract":"The development of representations about the active site structure of solid-phase catalysts, ranging from the work of H. Taylor to a modern understanding of the complex and multi-level structure of catalytic systems, is considered. The main types of active centers of catalysts for redox processes of deep, selective, and preferential conversion are analyzed. It is shown that for each type of reaction, regardless of the chemical nature of the catalyst components, the structure of the active center is characterized by certain common features and determines the direction of conversion. Particular attention is paid to the structure of active sites formed by the type of an isolated active center (\"Single Site Isolation\"), which allows achieving high selectivity of catalytic processes in the direction of target products obtaining and implementation of new reactions. In particular, the reaction of methane oxidative carbonylation to acetic acid was first carried out in a gas phase using molecular oxygen as an oxidant and catalysts whose active centers were presented by isolated Rh3+ ions in the composition of rhodium selenochloride. A separate type of active center is presented by atoms located on the grain boundaries of crystallites, which arise as a result of interfacing interaction between catalyst components: support, active component, modificator, as well as grain boundaries between homogeneous nanocrystallites in agglomerated systems. It is shown that an important role in the manifestation of catalytic properties plays the availability of an active center for reagents, caused by the spatial structure of catalysts. Zeolites, organometallic compounds (MOF), mesostructural oxides in which active centers are located inside the cavity channels are examples of such catalytic systems. The main strategy of research in the field of advanced catalysts is aimed at developing methods for the synthesis of catalytic materials, which provide formation as the maximum number of active centers, so their availability for reagents and subsequent conversion to target products. Designing such systems is a complex task, based on establishing a correlation between composition, structure, and size characteristics of catalytic materials.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84958665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New HPPOa technology for propylene oxide production: from laboratory reactor to commercial pilot installation","authors":"I.V. Shchutskyi, V. Brei, M. Sharanda, Y.V. Kas’kov, О.Yu. Dagaev, I.M. Pidsadyuk, A. Mylin, Y.O. Mykhailenko, O.Yu. Zienchenko","doi":"10.15407/kataliz2021.32.001","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.001","url":null,"abstract":"The development of HPPOa technology on production of propylene oxide from propylene and hydrogen peroxide with the use of acetonitrile as a solvent instead of methanol is shortly described. Laboratory studies included the development of a new catalyst and its testing in a flow fixed bed (4-10 cm3) reactor at 40-550C/3.0 MPa. Proposed TIS-1 catalyst was synthesized using dispersed Newsil 115 silica instead of traditional TEOS for TS-1 zeolite obtaining. Silica Ludox 40 and starch were used in the synthesis of TIS-1 catalyst also. On the basis of determined molar composition of reaction 60% H2O2 - propylene- 85% acetonitrile mixture and a load on catalyst the HPPOa (hydrogen peroxide to propylene oxide in acetonitrile) technology for a pilot installation with capacity of 2000 t/y has been developed. The main equipment – 3 reactors, 6 distillation columns, absorber, heat exchangers were made in Ukraine by Techinservice Manufacturing Group Ltd. At the beginning 2019, the construction of HPPOa installation at the olefin plant of Karpatnaftochim Ltd in Kalush began. The first start of this installation took place in June 2020. That is, in a very short time, 3 years after the start of laboratory tests. Technological HPPOa scheme includes epoxidation of propylene, preliminary separation of the product mixture, purification of propylene oxide, propylene compression, purification of propylene from propane, absorption of propylene with acetonitrile, regeneration of acetonitrile. The installation is a rather complex engineering system, some elements of which operate under both high (30 atm) and low (0.1 atm) pressure at temperatures from -30 to 1500C. Now the installation is brought to design capacity with the production of commercial propylene oxide with a polymer purity of 99.95% without the use of traditional ammonia and hydrazine. Fully automated installation is serviced by 4 operators working in two shifts. Consumption of 100% H2O2 and propylene per 1 ton of propylene oxide consists 0.68 and 0.75 tons, respectively. Ltd ”Karpatnaftochim” intends to build a facility for production of propylene oxide with a capacity of 130,000 tons per year using HPPOa technology.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"12 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91481926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Homogeneous catalytic oxidation of toluene under the ultrasonic action","authors":"S. Melnyk, V. Reutskyi, Y. Melnyk","doi":"10.15407/kataliz2021.32.063","DOIUrl":"https://doi.org/10.15407/kataliz2021.32.063","url":null,"abstract":"The regularities of toluene catalytic oxidation with molecular oxygen catalyzed by cobalt (II) acetate in a liquid phase under the ultrasonic action have been researched. It was found a close relationship between the temperature and pressure of the oxidation process. The relationship determines the reaction rate, the reaction products composition, and the toluene limiting conversion value. It was found that the ratio between a sonochemical reaction rate and a toluene oxidation reaction rate without ultrasonic action increases with increasing the reaction temperature both at the process initial stage and higher values of hydrocarbon conversion. Simultaneously, an increase in the rate of toluene oxidation reaction under the ultrasonic action was detected only at a temperature of 430–438 K and a pressure of 0.4 MPa. Under all other conditions the rate of sonochemical reaction is lower than the toluene oxidation rate without ultrasonic action. An extreme reaction rate dependence of the homogeneous catalytic toluene oxidation on pressure at constant temperature was revealed. It is established that the reaction rate decreases with pressure increasing under the ultrasonic action more significantly the higher the reaction temperature is. In general the sonochemical reaction rate is lower than the rate of catalytic toluene oxidation. It was shown that ultrasound affects the concentrations of all reaction products. The relationship between the product concentrations obtained in the sonochemical reaction and in the toluene oxidation reaction without ultrasonic treatment depends on temperature and pressure. It is established that the main changes in the quantitative composition of oxidation products are to increase/decrease the benzoic acid and benzyl alcohol concentrations under the ultrasonic action. The decrease in the sonochemistry reaction rate of toluene catalytic oxidation at the reaction initial stage and its simultaneous increase at higher values of hydrocarbon conversion, as well as changes in the reaction products selectivities, and the ultrasonic effect on the toluene limiting conversion indicate that the cavitation affects on the changes in the regularities of catalyst-intermediate complexes transformations.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"3 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83614565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Side-chain Alkylation of Toluene with Methanol, Modification and Deactivation of Zeolite Catalysts of the Reaction","authors":"Y. Voloshyna, O. Pertko","doi":"10.15407/kataliz2021.31.017","DOIUrl":"https://doi.org/10.15407/kataliz2021.31.017","url":null,"abstract":"The review deals with main aspects of the toluene methylation reaction on basic catalysts. The side reactions of decomposition of methanol to CO and H2 on strong basic sites and ring alkylation of toluene on Lewis acid sites (cations of high polarizing ability) hinder obtaining high yields of the target products – styrene and ethylbenzene. Both types of sites are necessary for the course of the target reaction. So optimizing their strength and quantity is an important prerequisite for the selectivity of the side-chain alkylation catalysts. The advantage of fojasite-based systems for this reaction was confirmed by the works of many researchers. However, the possibilities of use of zeolites of other structural types and representatives of a new generation of molecular sieves are being studied, as well as ways of modifying such materials to increase their catalytic efficiency. The main direction of modification is to regulate the balance of acidity and basicity. Effective charge of framework oxygen atoms, which determines basicity of zeolite framework, increases due to the introduction of guest compounds into the catalyst, and this effect is more significant than influence on basicity of ion exchange for cations of elements of low electronegativity. However, the role of this method of modifying in increasing the selectivity remains crucial due to potentiality to decrease the Lewis acidity of cations. Compounds of other elements and transition metals also are used for modification, as well as promotion with metallic copper and silver. Techniques are applied, but not widely, to deprive the external surface of crystallites of active sites. This method of modification is effective for slowing down their deactivation by coke. Acid sites, in particular BAS, are most often distinguished among the sites responsible for coke formation. The mechanism of coke formation in the absence of such centers is also proposed. On the whole, this issue not fully disclosed and requires a deeper study.","PeriodicalId":9649,"journal":{"name":"Catalysis and Petrochemistry","volume":"2015 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88917186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}