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  Subjects -> MATHEMATICS (Total: 864 journals)
    - APPLIED MATHEMATICS (68 journals)
    - GEOMETRY AND TOPOLOGY (19 journals)
    - MATHEMATICS (643 journals)
    - MATHEMATICS (GENERAL) (40 journals)
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    - PROBABILITIES AND MATH STATISTICS (75 journals)

MATHEMATICS (643 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 3)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2)
Academic Voices : A Multidisciplinary Journal     Open Access   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 6)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 20)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 9)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 4)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Decision Sciences     Open Access   (Followers: 4)
Advances in Difference Equations     Open Access   (Followers: 1)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 1)
Advances in Materials Sciences     Open Access   (Followers: 15)
Advances in Mathematical Physics     Open Access   (Followers: 6)
Advances in Mathematics     Full-text available via subscription   (Followers: 10)
Advances in Numerical Analysis     Open Access   (Followers: 3)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 5)
Advances in Pure Mathematics     Open Access   (Followers: 4)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2)
African Journal of Educational Studies in Mathematics and Sciences     Full-text available via subscription   (Followers: 5)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Afrika Matematika     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 7)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2)
Algebra Colloquium     Hybrid Journal   (Followers: 4)
Algebra Universalis     Hybrid Journal   (Followers: 2)
Algorithmic Operations Research     Full-text available via subscription   (Followers: 5)
Algorithms     Open Access   (Followers: 9)
Algorithms Research     Open Access  
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Mathematical Analysis     Open Access  
American Journal of Mathematics     Full-text available via subscription   (Followers: 6)
American Journal of Operations Research     Open Access   (Followers: 5)
American Mathematical Monthly     Full-text available via subscription   (Followers: 5)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 7)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access   (Followers: 1)
Analysis     Hybrid Journal   (Followers: 2)
Analysis and Applications     Hybrid Journal   (Followers: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4)
Analysis Mathematica     Full-text available via subscription  
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annales UMCS, Mathematica     Open Access   (Followers: 1)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Discrete Mathematics     Full-text available via subscription   (Followers: 6)
Annals of Mathematics     Full-text available via subscription  
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of the Alexandru Ioan Cuza University - Mathematics     Open Access  
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1)
Annals of West University of Timisoara - Mathematics     Open Access  
Annuaire du Collège de France     Open Access   (Followers: 5)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applications of Mathematics     Hybrid Journal   (Followers: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 4)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 1)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Numerical Analysis & Computational Mathematics     Hybrid Journal   (Followers: 5)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 2)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Arkiv för Matematik     Hybrid Journal  
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 17)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Journal of Current Engineering & Maths     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 6)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 1)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access  
Baltic International Yearbook of Cognition, Logic and Communication     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
BIBECHANA     Open Access  
BIT Numerical Mathematics     Hybrid Journal  
BoEM - Boletim online de Educação Matemática     Open Access  
Boletim Cearense de Educação e História da Matemática     Open Access  
Boletim de Educação Matemática     Open Access  
Boletín de la Sociedad Matemática Mexicana     Hybrid Journal  
Bollettino dell'Unione Matematica Italiana     Full-text available via subscription   (Followers: 1)
British Journal of Mathematical and Statistical Psychology     Full-text available via subscription   (Followers: 19)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 5)
Bulletin des Sciences Mathamatiques     Full-text available via subscription   (Followers: 4)
Bulletin of Dnipropetrovsk University. Series : Communications in Mathematical Modeling and Differential Equations Theory     Open Access   (Followers: 1)
Bulletin of Mathematical Sciences     Open Access   (Followers: 2)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Bulletin of the Malaysian Mathematical Sciences Society     Hybrid Journal  
Calculus of Variations and Partial Differential Equations     Hybrid Journal  
Canadian Journal of Science, Mathematics and Technology Education     Hybrid Journal   (Followers: 18)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CAUCHY     Open Access   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
CHANCE     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Annals of Mathematics, Series B     Hybrid Journal  
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Mathematics     Open Access  
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Collectanea Mathematica     Hybrid Journal  
College Mathematics Journal     Full-text available via subscription   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 1)
Communications On Pure & Applied Mathematics     Hybrid Journal   (Followers: 3)
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Complex Variables and Elliptic Equations: An International Journal     Hybrid Journal  
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Comptes Rendus Mathematique     Full-text available via subscription   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Concrete Operators     Open Access   (Followers: 4)
Confluentes Mathematici     Hybrid Journal  
COSMOS     Hybrid Journal  
Cryptography and Communications     Hybrid Journal   (Followers: 12)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 11)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 2)
Discrete Mathematics     Hybrid Journal   (Followers: 7)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Graph Theory and Applications     Open Access   (Followers: 2)
Electronic Notes in Discrete Mathematics     Full-text available via subscription   (Followers: 2)
Elemente der Mathematik     Full-text available via subscription   (Followers: 3)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Ensino da Matemática em Debate     Open Access  
Entropy     Open Access   (Followers: 4)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 4)
European Journal of Mathematics     Hybrid Journal   (Followers: 1)
European Scientific Journal     Open Access   (Followers: 2)
Experimental Mathematics     Hybrid Journal   (Followers: 3)
Expositiones Mathematicae     Hybrid Journal   (Followers: 2)
Facta Universitatis, Series : Mathematics and Informatics     Open Access  
Fasciculi Mathematici     Open Access  
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fixed Point Theory and Applications     Open Access   (Followers: 1)
Formalized Mathematics     Open Access   (Followers: 2)

        1 2 3 4 | Last

Journal Cover Catalysis in Industry
  [SJR: 0.182]   [H-I: 7]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 2070-0555 - ISSN (Online) 2070-0504
   Published by Springer-Verlag Homepage  [2335 journals]
  • Nontemplate sol–gel synthesis of catalytically active mesoporous
           titanosilicates
    • Authors: R. U. Kharrasov; M. R. Agliullin; R. R. Talipova; A. D. Badikova; B. I. Kutepov
      Pages: 287 - 292
      Abstract: A method for the nontemplate sol–gel synthesis of micro-mesoporous and mesoporous titanosilicates is developed using commercially available raw materials (a mixture of oligomer esters of orthosilicic acid (Ethylsilicate-40) and a water–alcohol solution of titanium(IV) ethoxide). The effect of the pH values of the reaction mixture on sol–gel synthesis is studied using the characteristics of the porous structure of titanosilicates. Samples of amorphous structure with different textural characteristics are obtained by varying the pH in the range of 3–10: specific surface area, 320–740 m2/g; micropore volume, 0.04–0.15 cm3/g; and mesopore volume, 0–0.92 cm3/g. It is shown that a sample of mesoporous titanosilicate obtained with alternating pH values has maximum catalytic activity in the oxidation reaction of 4-tert-butylphenol (TBP) in aqueous solutions of hydrogen peroxide. (Conversion of 4-tert-butylphenol, 45 wt %; selectivity of the formation of 4-tert-butylcatechol, 66 wt %. Conditions: 10 wt % of titanosilicate; TBP/H2O2 = 1/2; 75°C; 1 h).
      PubDate: 2016-10-01
      DOI: 10.1134/s207005041604005x
      Issue No: Vol. 8, No. 4 (2016)
       
  • Dehydrogenation of methanol over copper-containing catalysts
    • Authors: T. P. Minyukova; A. V. Khasin; A. A. Khassin; N. V. Shtertser; I. I. Simentsova; T. M. Yurieva
      Pages: 293 - 299
      Abstract: A comparative study of copper-containing catalysts with different chemical and phase compositions is performed to determine conditions for the implementation of the vapor phase and highly selective dehydrogenation of methanol to methyl formate or syngas. A thermodynamic analysis of the reaction is also performed. It is shown that Cu0 nanoparticles formed in the course of reductive activation reveal different selectivities with respect to the formation of methyl formate from methanol or its dehydrogenation with formation of syngas. By correctly selecting the catalyst composition and process conditions, high (90–100%) selectivity with respect to either methyl formate or syngas can be attained. Catalysts based on Cu–Zn hydrosilicate of the zincsilite type and on CuAlZn aurichalcite are highly selective in the process of methyl formate formation. An estimation based on experimental data shows that the productivity of Cu/SiO2 catalyst, the one most effective in dehydrogenation to syngas, is as high as 20 m3/h of syngas at a methanol vapor pressure of 1 atm, a temperature of 200°C, and a contact time of 0.5 s.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040073
      Issue No: Vol. 8, No. 4 (2016)
       
  • Synthesizing cyclic carbonates from olefin oxides and carbon dioxide. I:
           Catalysis with ionic liquids
    • Authors: A. V. Sulimov; A. V. Ovcharova; A. A. Ovcharov; T. A. Ryabova; G. M. Kravchenko; S. A. Lysanov
      Pages: 300 - 309
      Abstract: A review of catalytic systems based on ionic liquids used for promoting reactions between olefin oxides and carbon dioxide is presented. It is shown that ionic liquids based on imidazoles, pyridines, quaternary ammonium salts, and other compounds exhibit high activity in these processes and can serve as alternatives to conventional catalysts of cyclocarboxylation of olefin oxides under certain conditions. Specific features of the reactions between oxiranes and carbon dioxide in the presence of ionic liquids are considered, including reactions with the use of promoting additions based on metal salts. Mechanisms of the catalytic action of ionic liquids in syntheses of cyclocarbonates are described. Other works are critically analyzed to develop new lines in the catalysis of cyclocarboxylations of olefin oxides with ionic liquids.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040103
      Issue No: Vol. 8, No. 4 (2016)
       
  • A new method for producing substituted anthraquinones via diene synthesis
           
    • Authors: L. L. Gogin; E. G. Zhizhina; Z. P. Pai
      Pages: 310 - 315
      Abstract: The possibilities of developing catalytic processes for the synthesis of 2-methylanthraquinone from 1,4-naphthaquinone (NQ) and isoprene, and synthesizing 2,3-dimethylanthraquinone from NQ and 2,3-dimethylbutadiene in the presence of aqueous solutions of high-vanadium heteropoly acid (HPA) as a bifunctional catalyst are examined. Two methods for catalyst regeneration are discussed: oxidation with oxygen at \({P_{o{}_2}}\) = 0.3–0.4 MPa and with concentrated nitric acid at atmosphere pressure. It is shown that regeneration with nitric acid ensures deeper oxidation of the reduced catalyst. Complete restoration of the properties of the catalyst following regeneration offers the possibility of its repeated use in the processes discussed in this work.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040048
      Issue No: Vol. 8, No. 4 (2016)
       
  • Heterogeneous oligomerization of light alkenes: 80 years in oil refining
    • Authors: A. V. Lavrenov; T. R. Karpova; E. A. Buluchevskii; E. N. Bogdanets
      Pages: 316 - 327
      Abstract: Existing industrial technologies for the production of motor fuel compounds by the heterogeneous oligomerization of light С2–С4 alkenes are considered, along with ones promising for the practical use. Such basic types of systems used as heterogeneous catalysts in these processes as solid phosphoric acid, amorphous alumosilicates, zeolites, ion-exchange resins, anion-modified metal oxides, and nickel-containing catalysts, are described. Special attention is given to the dimerization of iso-butylene with the formation of iso-octene and its subsequent hydrogenation to iso-octane.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040061
      Issue No: Vol. 8, No. 4 (2016)
       
  • Investigating the process of heavy crude oil steam cracking in the
           presence of dispersed catalysts. II: Investigating the effect of
           Ni-containing catalyst concentration on the yield and properties of
           products
    • Authors: P. M. Eletskii; O. O. Mironenko; G. A. Sosnin; O. A. Bulavchenko; O. A. Stonkus; V. A. Yakovlev
      Pages: 328 - 335
      Abstract: The process of heavy crude oil (HCO) steam cracking under a batch regime at 425°C in the presence of Ni-containing nanodispersed catalyst (0.3–2.0 wt % with respect to Ni) is investigated. It is established that using this catalyst facilitates the upgrading of semi-synthetic oil produced from HCO: the Н: С ratio rises (in comparison to steam cracking with no catalyst), and the sulfur content and viscosity are reduced. The Н: С ratio in the liquid products grows slightly along with the catalyst content, but the yield of liquid products falls from 81 to 76% during the process with a simultaneous increase in the yield of coke and gaseous products (from 8 to 13 and from 2 to 4 wt %, respectively). Catalyst with coke residue is investigated by means of XRD and TEM. It is shown that nanosized particles of the Ni9S8 phase with sizes of 15–40 nm form from the catalyst precursor (Ni(NO3)2 · 6H2O) under the process conditions. The selection and investigation of catalytic systems for heavy crude oil cracking in the presence of superheated steam, along with optimization of the process conditions, are required to further enhance the efficiency of the upgrading process.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040036
      Issue No: Vol. 8, No. 4 (2016)
       
  • Stability of catalysts for the oxidative chlorination of methane
    • Authors: V. N. Rozanov; Yu. A. Treger; I. S. Silina
      Pages: 336 - 340
      Abstract: The effects on the stability of catalysts for the oxidative chlorination of methane due to evaporation of the active component (copper chloride) of the catalyst are studied. The volatility of copper chloride is shown to depend mainly on the catalyst composition and temperature. At a moderate 350°C in the reactor, the evaporation of copper chlorides after 5 h is 0.45% on a catalyst containing copper and potassium chloride and 0.72% on a catalyst containing lanthanum chloride. The stability of catalyst operation can be effectively maintained not only by decreasing the volatility of copper chloride, but also by feeding hydrochloric acid with dissolved copper chloride isolated from the reaction gas of methane oxychlorination at the outlet of the reactor (for the removal of reaction heat and the recycling of unconverted hydrogen chloride) back into the reactor.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040085
      Issue No: Vol. 8, No. 4 (2016)
       
  • Methanation of the carbon supports of ruthenium ammonia synthesis
           catalysts: A review
    • Authors: P. G. Tsyrul’nikov; K. N. Iost; N. B. Shitova; V. L. Temerev
      Pages: 341 - 347
      Abstract: The propensity of carbon support for methanation in a hydrogen-containing medium is a problem for active ruthenium ammonia synthesis catalysts, since this leads to the degradation of the support and the sintering of the active component. This review analyses some key works on approaches to methanation inhibition and their results to show that, on the whole, an algorithm for solving the methanation problem has been found, i.e., the graphitization of carbon supports at high temperatures (up to 2000°C) and the introduction of ruthenium promoters, specifically alkali (Cs, K) and alkali-earth (Ba) oxides, whose role is to modify the electron state of ruthenium and block the surface of a carbon support to prevent it from interacting with active hydrogen. The most efficient catalyst not liable to methanation up to 700°C and a hydrogen pressure of 100 atm has been found. The resulting analysis can be useful in selecting and preparing Me/C catalysts in which Me represents metals of the VIII Group and others.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040115
      Issue No: Vol. 8, No. 4 (2016)
       
  • Prospects for application of enzymatic interesterification of oils in the
           production of modified fats
    • Authors: Y. V. Samoylova; K. N. Sorokina; V. N. Parmon
      Pages: 348 - 353
      Abstract: This review discusses a recent state of research in the field of enzymatic biocatalysis in application for the production of modified food fats. Properties of biocatalysts for enzymatic interesterification both been currently under development and already applied in industry of vegetable oils are discussed. The main directions of research on development of new biocatalysts, including those based on the novel recombinant lipase enzymes, as well as the potential of targeted modifications in the composition of oils by optimization of the catalytic process are covered. The relevant analysis of the enzymatic interesterification of oils shows its potential for development of energy efficient and environmentally friendly processes for production of the high quality food products with the specified characteristics.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040097
      Issue No: Vol. 8, No. 4 (2016)
       
  • Mechanically activated enzymatic hydrolysis of yeast biomass
    • Authors: A. L. Bychkov; E. I. Ryabchikova; K. G. Korolev; T. F. Lomovskaya; O. I. Lomovskii
      Pages: 354 - 360
      Abstract: Experimental data obtained in studying processes that occur during the mechanoenzymatic hydrolysis of cell wall polymers of Saccharomyces cerevisiae yeast are presented. Special emphasis is placed on studying the reactivity of polymers contained in the supramolecular structure of cell walls, and on scaling the technology using pilot and industrial equipment. It is shown that mechanical treatment of yeast biomass allows us to alter the supramolecular structure of cell wall polymers and increase their reactivity in the enzymatic hydrolysis. Mechanical treatment disintegrates yeast cells and changes the supramolecular structure of polymers in their cell walls; the structural layers of a cell wall become disordered and diffused. A phenomenological model of mechanically activated enzymatic hydrolysis is proposed; the model is based on an autolocalization mechanism of the process. The domestic commercially available enzyme preparation CelloLux 2000 (OOO PA Sibbiopharm, Berdsk, Novosibirsk oblast) is used in this work. It is shown that changes in the supramolecular structure of yeast cell wall polymers occur during mechanically activated enzymatic hydrolysis. The yields of mannanoligosaccharides (1.1%) and mannanoproteins (2.7%) in the main extract are determined. Using pilot and industrial equipment at OOO PA Sibbiopharm, the technology is scaled and the production of a new mannanoligosaccharide product for animal husbandry is established. The pilot batch of the final product is effective against salmonellosis and is shown to increase the weight gain of experimental animals.
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040024
      Issue No: Vol. 8, No. 4 (2016)
       
  • Erratum to: “Hydrocracking of Vegetable Oil on Boron-Containing
           Catalysts: Effect of the Nature and Content of a Hydrogenation
           Component”
    • Authors: Yu. A. Chumachenko; A. V. Lavrenov; E. A. Buluchevskii; A. B. Arbuzov; T. I. Gulyaeva; V. A. Drozdov
      Pages: 361 - 361
      PubDate: 2016-10-01
      DOI: 10.1134/s2070050416040127
      Issue No: Vol. 8, No. 4 (2016)
       
  • Oxidation of methanol to formaldehyde in microchannel reactors: prospects
           and limitations
    • Authors: V. A. Chumachenko; E. V. Ovchinnikova; A. G. Gribovskii; L. L. Makarshin
      Pages: 199 - 204
      Abstract: Some features of the behavior of highly exothermic selective oxidation processes in a monolith microchannel reactor (MCR) are studied experimentally using the oxidation of methanol to formaldehyde on a Fe–Mo catalyst as an example. The process can be intensified considerably by intensively withdrawing heat from the reaction zone, operating at increased methanol concentrations of up to 12–12.5%, and using catalyst particles smaller than 0.25 mm to increase the useful product yield per unit of catalyst volume by 7–12 times, compared to multitubular reactors. The thermal operating mode of MCRs is close to the optimum theoretical regime for this class of processes, thereby making it easier to achieve high selectivity to formaldehyde. Due to the abovementioned reduction in the activity of Fe–Mo catalyst in MCRs, the prospects for using MCRs in this process must be estimated along with solving the problem of catalyst stability. The use of MCRs appears to be very promising and technologically sound when dealing with catalytic processes whose intensification is not accompanied by an appreciable reduction in activity.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030028
      Issue No: Vol. 8, No. 3 (2016)
       
  • Specifics of dimethyl ether synthesis from syngas over mixed catalysts
    • Authors: I. I. Lishchiner; O. V. Malova; A. L. Tarasov; S. V. Korobtsev; M. F. Krotov; B. V. Potapkin
      Pages: 205 - 212
      Abstract: Dimethyl ether (DME) synthesis from syngas over a mixture of a methanol synthesis catalyst (ZnO, 25.10 wt %; AuO, 64.86 wt %; Al2O3, 10.04 wt %) and a methanol dehydration catalyst (γ-A12O3) has been investigated for one-, two-, and three-layer catalyst beds. There is a common regularity for these three variants: with an increasing temperature, the total CO conversion decreases, the CO-to-methanol conversion decreases, and the CO-to-DME conversion increases. The largest values of DME selectivity and DME yield have been attained with the three-layer bed. The highest DME yield has been obtained at 250–285°C. Use of a mechanical mixture of the methanol synthesis catalyst and alumina makes it possible to efficiently obtain DME from syngas ballasted with nitrogen (20 vol %) at an H2/CO ratio of 1, which is unfavorable for methanol synthesis. The DME yield on the syngas input basis in this case with the ballast gas (nitrogen or CO2) taken into account can be about 10 wt %.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030077
      Issue No: Vol. 8, No. 3 (2016)
       
  • Effect of titanium–magnesium catalyst morphology on the properties of
           polypropylene upon propylene polymerization in a liquid monomer
    • Authors: I. I. Salakhov; A. Z. Batyrshin; S. A. Sergeev; G. D. Bukatov; A. A. Barabanov; M. A. Mats’ko; A. G. Sakhabutdinov; V. A. Zakharov
      Pages: 213 - 216
      Abstract: The effect of the particle size of an IK-8-21 domestic titanium-magnesium catalyst on the properties of polypropylene (PP) produced during the polymerization of propylene in a liquid monomer is studied. Catalysts with particle sizes of 20 to 64 μm are shown to have high activity and identical sensitivity to hydrogen and allow PP to be obtained with a narrow distribution of particles over size, high isotacticity, and close values of crystallinity, melting temperature, and physicomechanical properties. A slight decrease in the activity and bulk density of PP powder is observed when the average size of catalyst particles is increased from 20 to 43 μm. A more notable reduction in the activity and bulk density of PP powder is observed for catalyst with particle sizes of 62 to 64 μm. IK-8-21 catalyst is not inferior to its foreign analogues with respect to the properties of the resulting PP.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030107
      Issue No: Vol. 8, No. 3 (2016)
       
  • Investigating the process of heavy crude oil steam cracking over disperse
           catalysts. I: Selection of optimal steam cracking conditions without
           catalyst
    • Authors: P. M. Eletskii; O. O. Mironenko; S. A. Selishcheva; V. A. Yakovlev
      Pages: 217 - 223
      Abstract: The process of heavy crude oil steam cracking using semi-flow (with respect to water) and steadystate regimes at 425°C without catalyst is investigated. It is established that in the case of a semi-flow regime, water acts predominantly as a physical agent facilitating the distillation of hydrocarbon fractions and thus preventing their transformation into petroleum coke. A reduction in coke yield is observed for a steady-state regime in comparison to a semi-flow regime; the introduction of water results in enhanced conversion of the high-boiling fraction and an increased yield of light fractions in the composition of liquid products. Based on the obtained data, it is concluded that water plays a positive role during the conversion of heavy crude oil, and that the steam cracking process is promising for production of lighter synthetic and/or semi-synthetic oils.
      PubDate: 2016-07-01
      DOI: 10.1134/s207005041603003x
      Issue No: Vol. 8, No. 3 (2016)
       
  • Prospects for using Mo- and W-containing catalysts in hydroisomerization:
           A patent review. II: Catalysts based on molybdenum and tungsten carbides
    • Authors: G. A. Urzhuntsev; E. G. Kodenev; G. V. Echevskii
      Pages: 224 - 230
      Abstract: Patent information on the production of catalytic systems containing molybdenum and tungsten carbides and their application in the hydroisomerization of paraffinic hydrocarbons is reviewed. Analysis shows that modifying acid supports with molybdenum and tungsten carbides solves the problem of creating a stable catalyst for the hydroisomerization of paraffinic fractions. The resulting catalyst is resistant to sulfurcontaining impurities in hydroisomerization feedstock.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030120
      Issue No: Vol. 8, No. 3 (2016)
       
  • Endurance tests and kinetic experiment in a plug-flow reactor with a fixed
           catalyst bed
    • Authors: E. A. Karalin; A. V. Oparkin; A. G. Abramov; S. B. Pavlov; N. F. Murtazin; D. M. Appakova; D. V. Ksenofontov; N. P. Miroshkin; Kh. E. Kharlampidi
      Pages: 242 - 247
      Abstract: As an example of the liquid-phase hydrogenation of methyl-phenol ketone to 1-phenylethanol, variants of the construction of a pilot reactor are considered for performing long-term tests of heterogeneous catalysts of a fixed bed. Calculations for the reactor unit during hydrogenation on NTK-11 are presented as an example. It is shown that a cascade of three adiabatic reactors with a catalyst bed height of 4.5 m each is needed to ensure a residual reactant concentration below 1 wt %.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030041
      Issue No: Vol. 8, No. 3 (2016)
       
  • Upgrading the industrial process flowsheet for the dehydration of
           methylbutenes to isoprene. II: Analysis of plant test results and
           industrial implementation of the upgraded design
    • Authors: A. A. Lamberov; Kh. Kh. Gilmanov; R. R. Gilmullin; M. V. Nazarov; P. V. Urtyakov; Yu. Nekhidzha
      Pages: 248 - 256
      Abstract: Pilot tests of technology for the dehydration of methylbutenes to isoprene are performed in a tworeactor system with an additional supply of an overheated gas into the interreactor space. The tests are performed on a pilot plant with two adiabatic reactors. The total volume of the catalyst charge is 60 dm3, the temperatures are 565–620°С, the contact time is 0.18–0.25 s, the raw material is diluted with steam in a weight ratio of С5Н10: Н2О = 1.0: (6.0–30.0), and the excess pressure is 0.6–0.7 kgf/cm2. The dependence of the isoprene concentration in the contact gas on the heat energy supplied by the raw material and steam is determined under conventional conditions of the process and in a pseudo-isothermal mode via an additional supply of overheated gas into the interreactor space. It is shown that the isoprene yield is increased by 10–12% by using the upgraded mode. The conditions for conducting the industrial process are determined based on the obtained results. After upgrading the design, tests are performed at the synthetic rubber factory of PAO Nizhnekamskneftekhim on a plant for the dehydrogenation of methylbutenes in the reactor with a doublelayer catalyst bed (nine tons per layer). The patterns established during the pilot tests generally prove to be true, but the selectivity of the process is reduced due to a number of design flaws. Corrective measures are outlined. Comparison of the experimental results and the calculated values confirm the accuracy of the mathematical model.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030065
      Issue No: Vol. 8, No. 3 (2016)
       
  • Pretreatment of rice husk in a pilot scale mill for further enzymatic
           hydrolysis
    • Authors: E. M. Podgorbunskikh; A. L. Bychkov; O. I. Lomovskii
      Pages: 274 - 279
      Abstract: The effect of the mechanical activation of rice husk on the reactivity of its carbohydrates was studied. The activation was performed in a pilot-scale centrifugal roller mill. The mechanical treatment of the raw material led to an increase in its reactivity due to the increase in the specific surface area and amorphization of the crystalline regions of cellulose. The optimum process conditions of activation, leading to the preparation of a reactive product from rice husk, were determined: rotor frequency 1500 rpm, raw material feed rate 30 kg/h. The rice husk particles were ground to 45–50 μm under these conditions. These changes led to a sevenfold increase of the yield of low-molecular carbohydrates in the complete enzymatic hydrolysis of the material.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030090
      Issue No: Vol. 8, No. 3 (2016)
       
  • Lactic acid production using free cells of bacteria and filamentous fungi
           and cells immobilized in polyvinyl alcohol cryogel: A comparative analysis
           of the characteristics of biocatalysts and processes
    • Authors: O. V. Maslova; O. V. Sen’ko; N. A. Stepanov; E. N. Efremenko
      Pages: 280 - 285
      Abstract: The results from studies and a comparative analysis of process characteristics are presented for lactic acid (LA) production from glucose, performed under batch conditions of the long-duration use of different biocatalyst samples comprising cells of Lactobacillus сasei bacteria and Rhizopus oryzae filamentous fungi immobilized in polyvinyl alcohol (PVA) cryogel or applied as concentrated suspensions. It is established that for LA production, the bacteria and fungi must be used in the form of PVA-cryogel-immobilized cells because their half-life in this form is considerably longer than that of concentrated cell suspensions. After 200 h of the batch use of the same immobilized cell samples, the amounts of accumulated LA were similar for both fungal (920 ± 5 g) and bacterial (895 ± 5 g) biocatalysts. The fungal biocatalyst, however, was characterized by a twice higher rate of substrate conversion to product (0.92 g LA per 1 g glucose) than the bacterial biocatalyst. The half-life of the immobilized fungal biocatalyst was 80 days (96 working cycles), ten times longer than that of the bacterial biocatalyst. A comparison of our data and the literature data demonstrated the promise of using fungal cells immobilized in PVA cryogel to produce LA: the process based on their use is superior to all known processes in its main indicators, i.e., the rate of LA conversion to glucose and the maximum accumulated concentration of the product.
      PubDate: 2016-07-01
      DOI: 10.1134/s2070050416030089
      Issue No: Vol. 8, No. 3 (2016)
       
 
 
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