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  Subjects -> MATHEMATICS (Total: 955 journals)
    - APPLIED MATHEMATICS (82 journals)
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    - MATHEMATICS (706 journals)
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MATHEMATICS (706 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 4)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 3)
Academic Voices : A Multidisciplinary Journal     Open Access   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 7)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 15)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 27)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 11)
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: 6)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
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: 6)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 18)
Advances in Decision Sciences     Open Access   (Followers: 3)
Advances in Difference Equations     Open Access   (Followers: 3)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 2)
Advances in Materials Sciences     Open Access   (Followers: 14)
Advances in Mathematical Physics     Open Access   (Followers: 3)
Advances in Mathematics     Full-text available via subscription   (Followers: 10)
Advances in Numerical Analysis     Open Access   (Followers: 4)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 6)
Advances in Pure Mathematics     Open Access   (Followers: 5)
Advances in Science and Research (ASR)     Open Access   (Followers: 4)
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: 11)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Al-Jabar : Jurnal Pendidikan Matematika     Open Access  
Algebra and Logic     Hybrid Journal   (Followers: 5)
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: 11)
Algorithms Research     Open Access   (Followers: 1)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
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: 6)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 8)
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: 11)
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: 12)
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)
ANZIAM Journal     Open Access   (Followers: 1)
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: 11)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 6)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 6)
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 Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 3)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 2)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
Armenian Journal of Mathematics     Open Access  
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 20)
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: 4)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access   (Followers: 1)
Baltic International Yearbook of Cognition, Logic and Communication     Open Access   (Followers: 1)
Basin Research     Hybrid Journal   (Followers: 5)
BIBECHANA     Open Access   (Followers: 2)
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: 21)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 11)
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: 1)
Bulletin of Symbolic Logic     Full-text available via subscription   (Followers: 2)
Bulletin of the Australian Mathematical Society     Full-text available via subscription   (Followers: 1)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 4)
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)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
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: 1)
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: 4)
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Combinatorics and Optimization     Open Access  
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 2)
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: 8)
Compositio Mathematica     Full-text available via subscription   (Followers: 1)
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: 5)
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: 8)
Concrete Operators     Open Access   (Followers: 5)
Confluentes Mathematici     Hybrid Journal  
Contributions to Game Theory and Management     Open Access  
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  
Current Research in Biostatistics     Open Access   (Followers: 9)
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 10)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 29)
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: 3)
Differentsial'nye Uravneniya     Open Access  
Discrete Mathematics     Hybrid Journal   (Followers: 8)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae - General Algebra and Applications     Open Access  
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Diskretnaya Matematika     Full-text available via subscription  
Dnipropetrovsk University Mathematics Bulletin     Open Access  
Doklady Akademii Nauk     Open Access  
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Eco Matemático     Open Access  
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Differential Equations     Open Access  
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: 4)

        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  [2352 journals]
  • Methane pyrolysis on deposited resistive MeO x /carborundum catalysts,
           where MeO x is MgO, CaO, MgO/Al 2 O 3 , MgO/ZrO 2 , CaO/Al 2 O 3 , and
           CaO/ZrO 2
    • Authors: S. S. Sigaeva; V. L. Temerev; N. V. Kuznetsova; P. G. Tsyrul’nikov
      Pages: 277 - 282
      Abstract: Thermostable oxide catalysts (Al2O3, ZrO2, MgO, and CaO) deposited onto a resistive support (carborundum) are investigated for oxygen-free methane pyrolysis. Adding MgO, ZrO2, and Al2O3 to pure carborundum considerably improves methane conversion and selectivity toward acetylene. In contrast, the deposition of СаO reduces the total activity of deposited catalysts. The maximum selectivity toward acetylene (23.6%) is achieved on MgO/SiC catalyst with methane conversion of 68% at T = 1290°C. Examination of the MgO/SiC sample shows that the catalyst retains its catalytic characteristics without decomposition (methane conversion, ≈69%; selectivity toward acetylene, ≈22%) for more than 4 h of operating in methane pyrolysis (15% СН4 in nitrogen) at a temperature of 1300°С as a result of there being no carbon corrosion of the carborundum resistive support, in comparison to the metal catalysts.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040080
      Issue No: Vol. 9, No. 4 (2017)
       
  • Prospects for the direct catalytic conversion of methane into useful
           chemical products
    • Authors: L. G. Pinaeva; A. S. Noskov; V. N. Parmon
      Pages: 283 - 298
      Abstract: The literature data on the direct catalytic conversion of methane into useful chemical products (Н2, С2+ hydrocarbons, methanol, formaldehyde, and higher oxygenates) were analyzed. Processes based on these reactions have not yet been commercialized. For each reaction, the catalytic systems were revealed on which the characteristics (primarily, the yield of the desired product) are maximum, and the degree of their approximation to the level at which commercialization is possible was determined. Currently, the most suitable processes for pilot and industrial production may be the syntheses of С2+ and alkylaromatic hydrocarbons by oxidative condensation (dimerization) of methane and by the reaction of methane with С3–С6 alkanes, respectively. The problem of fast deactivation of catalysts in the synthesis of hydrocarbons of the gasoline fraction by methylation of olefins can be solved due to significant progress in the development of new modifications of zeolites and aluminosilicates. The main limitations on the implementation of methane pyrolysis into carbon and H2 are the insufficient demand for the types of carbon materials produced and low strength characteristics of the available catalysts in the case of the process performed in the moving bed. For some products (methanol, formaldehyde), the yields are too low for commercialization, while for others (higher oxygenates) only the possibility of their production was shown.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040067
      Issue No: Vol. 9, No. 4 (2017)
       
  • Hydrodeoxygenation of methyl-substituted ketones using the composite
           loading of hydrogenation and dehydration catalysts
    • Authors: D. P. Ivanov; A. S. Kharitonov; L. V. Pirutko; A. S. Noskov; P. A. Abrashenkov; V. A. Golovachev; D. O. Kondrashev; A. V. Kleimenov
      Pages: 299 - 307
      Abstract: The hydrogenation/hydrodeoxygenation of methyl-substituted carbonyl compounds to preserve the isomeric structure of a product is one way of controlling its amount of oxygen and improving the chemical stability of motor fuel components. The integration of hydrogenation and dehydration catalysts in one reaction space is an bright example of processes that proceed on these catalysts and positively affect each other. In comparison with the hydrogenation Ni-catalyst, the transformation of 2,4-dimethyl-3-pentanone into 2,4-dimethylpentane over the same catalyst loaded jointly with a zeolite is accompanied by a several-fold increase in hydrogenation rate and operational stability. In the process, the complete hydrodeoxygenation of the parent ketone is observed. Such composite loading can be used to replace bifunctional catalysts.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040043
      Issue No: Vol. 9, No. 4 (2017)
       
  • Hydrooligomerization of unsaturated hydrocarbons as a basis of new
           technologies for the production of motor fuel compounds
    • Authors: T. R. Karpova; E. A. Buluchevskii; A. V. Lavrenov
      Pages: 308 - 316
      Abstract: A brief analysis is performed for the current state of processes for the production of motor fuels based on the consecutive oligomerization and hydrogenation reactions of unsaturated hydrocarbons. Some new butene hydrooligomerization catalysts based on the bifunctional NiO/В2O3–Al2O3, PdO/В2O3–Al2O3, and MoO3/В2O3–Al2O3 systems are considered. It is shown that the best process performance parameters (a 67 wt % yield of liquid С5+ products at a butene conversion of more than 90%) are achieved with PdO/В2O3–Al2O3 catalyst prereduced in a hydrogen medium. The possibility of acetylene hydrooligomerization on NiO/B2O3–Al2O3 catalyst is demonstrated in principle. It is established that the presence of nickel(II) cations chemically bonded to the surface of a support is of fundamental importance for both acetylene hydrooligomerization and ethylene oligomerization.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040055
      Issue No: Vol. 9, No. 4 (2017)
       
  • Characteristics and catalytic activity of platinum reforming catalysts
           based on aluminum oxide modified by organic acids
    • Authors: V. Yu. Tregubenko; I. E. Udras; T. I. Gulyaeva; A. S. Belyi
      Pages: 317 - 322
      Abstract: The effect of treating aluminum oxide with organic acids (acetic acid, oxalic acid) on the dispersity, composition, and catalytic properties of the platinum sites of reforming catalysts is investigated. It is established that due to the high number of support defects, a Pt/О х -Al2O3 sample prepared on the basis of aluminum oxide treated with oxalic acid solution has the the highest activity. The role the acid modification of a support plays in the formation of charged atoms of platinum, resulting in an increase of catalytic activity, is established.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040110
      Issue No: Vol. 9, No. 4 (2017)
       
  • A new n -alkane hydroisomerization catalyst modified with nanosized
           molybdenum carbides and its catalytic properties in diesel fraction
           hydroisomerization. I. Synthesis and physicochemical properties of
           different acidic supports for hydroisomerization catalysts
    • Authors: G. V. Echevskii; A. V. Toktarev; D. G. Aksenov; E. G. Kodenev
      Pages: 323 - 330
      Abstract: Hydroisomerization catalysts based on nanosized molybdenum carbides are developed. Such catalysts are resistant to sulfur compounds and can be used for the synthesis of waxy diesel fuels with the same characteristics as on platinum-containing catalysts. In the first part of this work, acidic supports with different types of porous structure and concentrations and strengths of Brønsted acidic sites (e.g., silicoaluminophosphate SAPO-31, zeolite ZSM-12, modified zeolite Beta, and desiliconized zeolite ZSM-5) are synthesized for a new type of catalysts. Their physicochemical properties are studied by means of adsorption, temperature- programmed desorption of ammonia (TPD-NH3), nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM).
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040031
      Issue No: Vol. 9, No. 4 (2017)
       
  • Bacterial degradation of ecotoxic dehydroabietic acid
    • Authors: K. M. Cheremnykh; V. V. Grishko; I. B. Ivshin
      Pages: 331 - 338
      Abstract: The possibility of biodegrading dehydroabietic acid (С20Н28О2, САS: 1740-19-8, abieta-8,11,13- trien-18-oic acid) (DAA), a toxic tricyclic diterpenoid, accumulated in the waste waters of the pulp and paper industry is studied using actinobacterial strain Dietzia maris IEGM 55Т. Cells of the strain Dietzia maris IEGM 55Т are shown to be resistant to DAA (MIC, 390 mg/L). The strain is not able to use DAA as its sole source of carbon and energy. DAA (500 mg/L) decays almost completely in 7 days when the bacteria are preliminarily grown with n-hexadecane. The DAA effect on the viability and respiratory activity of the bacteria is studied. Analysis of the antimicrobial activity shows that extracts of the obtained metabolites are not toxic, in contrast to the initial substrate. The resulting data expands our views on the catalytic activity of actinobacteria and their impact in decontaminating natural ecosystems that contain ecotoxicants.
      PubDate: 2017-10-01
      DOI: 10.1134/s207005041704002x
      Issue No: Vol. 9, No. 4 (2017)
       
  • Biocatalytic production of extracellular exopolysaccharide dextran
           synthesized by cells of Leuconostoc mesenteroides
    • Authors: N. A. Stepanov; O. V. Senko; E. N. Efremenko
      Pages: 339 - 343
      Abstract: Results are presented from studies and a comparative analysis of the production of the commercially important product dextran from sucrose using fed-batch cultivated cells of the Leuconostoc mesenteroides subsp. dextranicum B-5481 bacterium either immobilized in a polyvinyl alcohol (PVA) cryogel or in the form of a suspension. It is shown that under identical process conditions, the concentration of dextran is 1.2 times higher when using immobilized cells instead of free cells. The high productivity of dextran formation (4.2 g/(L h)) under the conditions of fed-batch cultivation of the immobilized cells and the ability of these cells to function without losing their metabolic activity for at least five operating cycles are demonstrated. The productivity of the developed biocatalyst is 5 times higher than that of Weissella confusa cells immobilized in a calcium alginate gel and 34 times higher than that of Leuconostoc mesenteroides KIBGE HA1 cells immobilized in a polyacrylamide gel. The molecular weight of the dextran samples produced by the immobilized L. mesenteroides B-5481 cells is half that of the polymer produced by the free cells, expanding the range of possible applications of the polysaccharide with no additional hydrolysis.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040109
      Issue No: Vol. 9, No. 4 (2017)
       
  • Highly concentrated populations of Aureobasidium pullulans cells in
           biocatalytic pullulan production processes
    • Authors: O. V. Senko; E. N. Efremenko
      Pages: 344 - 348
      Abstract: Results are presented from studies and a comparative analysis of highly concentrated populations of free and immobilized Aureobasidium pullulans Y-4137 cells in the biocatalytic processes of pullulan production in glucose-containing media. The possibility of effectively using the developed biocatalyst in the form of immobilized cells is demonstrated. The process characteristics are determined for pullulan production from hydrolysates of various sources of renewable feedstocks (Jerusalem artichoke tubers, aspen wood, Chlorella vulgaris microalgal biomass, and potato pulp) under the action of the catalyst. It is established that A. pullulans cells immobilized in a polyvinyl alcohol (PVA) cryogel consume glucose 1.5 times faster and accumulate a 1.7 times higher concentration of the target polysaccharide in the medium than free cells. The immobilized cells can function for at least 15 operating cycles with a slight (no more than 10%) reduction in their metabolic activity. Analysis of the obtained data confirms that cell immobilization in a PVA gel for the production of pullulan allows us to shorten the duration of operating cycles in similar processes by a factor of 1.4 while reaching a comparable yield of the target product.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040079
      Issue No: Vol. 9, No. 4 (2017)
       
  • Preparation and properties of new biocatalysts for the degradation of
           nonstarch plant polysaccharides
    • Authors: A. P. Sinitsyn; E. A. Rubtsova; I. A. Shashkov; A. M. Rozhkova; O. A. Sinitsyna; E. G. Kondrat’eva; I. N. Zorov; D. A. Merzlov; D. O. Osipov; V. Yu. Matys
      Pages: 349 - 356
      Abstract: Recombinant strains of Penicillium verruculosum are developed that produce the homologous endoglucanase 2 (Eg2) and the P. canescens heterologous xylanase E (XylE). The recombinant strains are used to obtain new biocatalysts, i.e., enzyme preparations (EPs) that are substantially enriched with Eg2 and XylE. These preparations are highly active with respect to nonstarch plant polysaccharides (NPSes): cellulose, β-glucan, and xylan. The qualitative and quantitative compositions of the new EPs are studied by protein chromatography. It was shown that the EPs contained (in terms of total protein content) ~16–17% Eg2, 48–63% XylE, and 17–30% cellobiohydrolases, while the EP obtained using the recipient strain contained 1.4% Eg2, ~60% cellobiohydrolase and no XylE. The optimum pH values for cellulase (with respect to carboxymethylcellulose, CMC) and the xylanase activity of the EPs are 4.0 and 5.5, respectively. The EPs exhibit the abovementioned activities within a wide range of pH (3 to 7). The EPs exhibit CMC-ase and xylanase activities in the temperature range of 20–80°С with maxima at 60 and 70°C, respectively. The xylanase activity of the new EPs is virtually uninhibited by protein inhibitors of rye.
      PubDate: 2017-10-01
      DOI: 10.1134/s2070050417040092
      Issue No: Vol. 9, No. 4 (2017)
       
  • Pyrolysis of methane on oxide catalysts supported by resistive fechral and
           carborundum
    • Authors: S. S. Sigaeva; V. L. Temerev; N. V. Kuznetsova; P. G. Tsyrul’nikov
      Pages: 181 - 188
      Abstract: Catalysts on resistive supports, namely, on the thermally stable metal alloy fechral (FeCrAl) and carborundum (silicon carbide SiC) were studied in the pyrolysis of methane into acetylene. The active components chosen for deposition on carborundum were oxides corresponding to those present on the surface of the heat-treated fechral alloy: iron, chromium, and aluminum oxides, as well as zirconium and silicon oxides. The deposition of oxides on carborundum leads to an increase in methane conversion compared to the starting carborundum. The maximum acetylene selectivity was obtained using the ZrO2/SiC and Al2O3/SiC catalysts. In contrast, the deposition of the same oxides on fechral leads to a decrease in the activity and acetylene selectivity compared with those of the starting heat-treated fechral. On the other hand, the deposition of oxides on fechral results in an increase in the temperature range of the catalyst operation and its stability over time. In the case of carborundum, the deposition of oxides does not affect these characteristics. The study of the starting supports fechral and carborundum and supports with metal oxides showed that high acetylene selectivity correlates with the formation of carbon fibers on the catalyst surface. These fibers mainly form on the surface of alumina, zirconia, and silica.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030114
      Issue No: Vol. 9, No. 3 (2017)
       
  • Kinetics of vapor-phase dehydration of glycerol into acrolein on the BAO-1
           heterogeneous catalyst
    • Authors: S. M. Danov; A. L. Esipovich; A. S. Belousov; A. E. Rogozhin; E. A. Kanakov
      Pages: 189 - 197
      Abstract: The vapor-phase dehydration of glycerol on the heterogeneous catalyst 0.5B2O3/γ-Al2O3 (BAO-1) was studied. The kinetic model of the process was developed based on the data obtained in a differential reactor. To evaluate the kinetic constants of the generalized mathematical models of the kinetics of vapor-phase dehydration of glycerol, we used the differential evolution method implemented in the Mathematica 5.0 program. The calculated activation energy of the target reaction of acrolein formation was 50.18 ± 0.11 kJ/mol. The adequacy of the obtained equations was assessed using the Fisher test. The optimum conditions of the vaporphase dehydration of glycerol were determined using the proposed kinetic equations (reaction temperature 330°C, glycerol concentration in the supply stream 30%, and catalyst load 0.0338 L/(gcat min). The obtained data may be used in calculations for large units for acrolein production by glycerol dehydration.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030047
      Issue No: Vol. 9, No. 3 (2017)
       
  • A new alkylate production process
    • Authors: S. N. Khadzhiev; I. M. Gerzeliev; O. S. Vedernikov; A. V. Kleymenov; D. O. Kondrashev; N. V. Oknina; S. E. Kuznetsov; Z. A. Saitov; M. N. Baskhanova
      Pages: 198 - 203
      Abstract: A new technology for alkylation on solid AlkiRAN-GPN catalyst with process performance characteristics and an attained material balance competitive with existing sulfuric and hydrofluoric acid alkylation technologies is presented. Data on the effect such parameters as temperature, pressure, iso-butane: olefin ratio, and feedstock hourly space velocity (FHSV)) have on the process’s performance characteristics are given, and their optimum values are recommended. It is shown that using a sectioned reactor at a constant inlet iso-butane: olefin ratio ensures a higher internal ratio of these components and an increase in the total concentration of alkylate in the reaction products at a specified internal iso-butane: olefin ratio. This also lengthens the period of catalyst interregeneration with no losses in the process’s productivity and selectivity. The use of a zeolite based on faujasite in the rare-earth element–calcium form (REECaHY) and ultrastable zeolites as catalysts is substantiated. Higher values of olefin conversion and the alkyl gasoline yield are observed when these zeolites are used. To test the new technology, a demonstration plant of iso-butane alkylation with olefins on heterogeneous catalysts with an alkylate production capacity of 1 t/day is constructed. The results from studies are to be used in developing the basic design of an industrial plant. The construction of the first industrial plant of alkylation on a heterogeneous catalyst with an alkyl gasoline production capacity of 100000 t/year is planned at AO Gazprom Neft Moscow Oil Refinery.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030059
      Issue No: Vol. 9, No. 3 (2017)
       
  • Hydroprocessing of straight run diesel mixed with light cycle oil from
           fluid catalytic cracking, using sulfide NiMo catalyst on
           zeolite-containing supports
    • Authors: G. A. Bukhtiyarova; E. N. Vlasova; P. V. Aleksandrov; A. V. Toktarev; Yu. V. Patrushev; A. S. Noskov; D. O. Kondrashev; V. A. Golovachev; A. V. Kleymenov; P. A. Abrashenkov; S. E. Kuznetsov; V. V. Galkin
      Pages: 212 - 220
      Abstract: It is proposed that the sulfide NiMo system supported on alumina-SAPO-31 composite (NiMo/Al2O3-SAP catalyst) be used to obtain high-quality diesel fuel from a mixture of straight run diesel (SRGO) and light cycle oil (LCO) produced by fluid catalytic cracking (FCC). It is shown that the use of this catalyst ensures the synthesis of diesel fuel of higher quality upon hydroprocessing a feedstock with 30 wt % LCO, compared to the traditional sulfide NiMo/Al2O3 or CoMo/Al2O3 catalysts. It is found that the content of aliphatic hydrocarbons is raised in the products of hydrotreatment, compared to the initial feedstock. This confirms the ability of NiMo/Al2O3-SAP catalyst to facilitate the reaction of ring opening. Using the proposed catalyst should improve the quality of diesel fuels obtained via the hydroprocessing of LCO-containing feedstock.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030035
      Issue No: Vol. 9, No. 3 (2017)
       
  • Catalytic steam cracking of heavy crude oil with molybdenum and nickel
           nanodispersed catalysts
    • Authors: O. O. Mironenko; G. A. Sosnin; P. M. Eletskii; Yu. K. Gulyaeva; O. A. Bulavchenko; O. A. Stonkus; V. O. Rodina; V. A. Yakovlev
      Pages: 221 - 229
      Abstract: The catalytic steam cracking (CSC) of heavy crude oil with high amount of sulfur (4.3 wt %) and high-boiling fractions (>500°C) is studied using Mo and Ni nanodispersed catalysts under static conditions (in an autoclave) at 425°C. Experiments on thermal cracking, steam cracking, and catalytic cracking without water are performed to compare and identify the features of CSC. The relationship between the composition and properties of liquid and gaseous products and process conditions, the type of catalyst, and water is studied. Using Ni catalyst in CSC raises the H: C ratio (1.69) in liquid products, compared to other types of cracking, but also increases the yield of coke and gaseous products, so the yield of liquid products falls. When Mo catalyst is used in CSC, low-viscosity semi-synthetic oil with a higher H: C ratio (1.70) and the lowest amount of sulfur in liquid products (2.8 wt %) is produced. XRF and HRTEM studies of the catalyst-containing solid residue (coke) show that under CSC conditions, nickel is present in the form of well-crystallized nanoparticles of Ni9S8 15–40 nm in size, while molybdenum exists in two phases: MoO2 and MoS2, the ratio between which depends on the conditions of the transformation of heavy crude oil. The findings indicate that CSC is a promising process for improving heavy crude oil.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030084
      Issue No: Vol. 9, No. 3 (2017)
       
  • Catalyst for selective hydrotreating of catalytic cracking gasoline
           without preliminary fractionation
    • Authors: K. A. Nadeina; V. Yu. Pereima; O. V. Klimov; G. I. Koryakina; A. S. Noskov; D. O. Kondrashev; A. V. Kleymenov; O. S. Vedernikov; S. E. Kuznetsov; V. V. Galkin; P. A. Abrashenkov
      Pages: 230 - 238
      Abstract: A new CoMo catalyst for selective hydrotreating of FCC gasoline has been developed; the catalyst is intended for the production of hydrotreated gasoline with up to 10 ppm of sulfur and with a research octane number decreased by less than 1.0. The new catalyst allows hydrotreating of FCC gasoline without its preliminary separation into the light and heavy fractions. The hydrotreating conditions were as follows: hourly space velocity 2.2 h–1, temperature 270°C, pressure 2.5 MPa, H2/feed = 150 m3/m3. The high degree of hydrodesulfurization at minimum decrease in the octane number is achieved due to the high activity of the developed catalyst in hydrodesulfurization of the sulfur-containing components of the feedstock and conversion of reactive high-octane olefins of FCC gasoline into less reactive derivatives with high octane numbers. The catalyst is a CoMoS phase deposited on a support containing amorphous aluminosilicate and γ-Al2O3. The method for the preparation of the catalyst is adapted to the equipment of Russian plants and feedstocks. The parameters of hydrotreating using this catalyst ensure the hydrotreating of FCC gasoline to a residual sulfur content of less than 10 ppm with minimum redesign of the equipment currently available at Russian refineries.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030096
      Issue No: Vol. 9, No. 3 (2017)
       
  • Development and introduction of a highly efficient catalyst for the
           butane–butylene fraction oligomerization process for the production of a
           high-octane automobile gasoline compound
    • Authors: D. O. Kondrashev; A. V. Andreeva
      Pages: 239 - 246
      Abstract: The main stages in developing a technology for the production of high-silica ZSM-5 zeolite-based catalyst for the butane–butylene fraction (BBF) oligomerization process are described. The application of a new zeolite surface modification procedure allows the attainment of higher selectivity and target product yields (compared to familiar analogs) and the synthesis of more branched (and thus more high-octane) oligomers at lower pressures. The introduction of promoting metal Ga raises the target gasoline fraction yield by 0.9%, compared to the unpromoted catalyst. Comparative pilot tests of industrial (BAK-70U) and the developed (Ga-ZSM-5/Al2O3) BBF oligomerization catalysts are performed under the following conditions: pressure, 1.5 MPa; initial working temperature, 300°C; feedstock hourly space velocity (FHSV), 1.5 mL BBF/(mL cat h). It is shown that using modified ZSM-5 based catalyst results in a gasoline fraction yield 7% higher than with BAK-70U. The higher quality of the oligomerizate obtained on Ga-ZSM-5/Al2O3 is observed throughout the period of tests (191 h): MON is 2 points higher, and the concentration of gums is 50% lower. The results from these studies and tests are used for the development and industrial implementation of a technology for the production of the KOB-1 zeolite oligomerization catalyst: 2.5 t of industrial catalyst has been produced by September of 2016 at the industrial facilities of ZAO Redkino Catalyst Plant. The next important stage in the implementation of the Gazprom Netf innovative development strategy in oil refining is a pilot run of the new oligomerization catalyst in the combined industrial MTBE–oligomerizate production plant of Gazprom Neft Moscow Oil Refinery. The introduction of the KOB-1 catalyst at the Gazprom Neft Oil Refinery will be an important step in improving the efficiency of technologies for the production of high-margin products, especially compounds of commercial automobile gasoline.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030072
      Issue No: Vol. 9, No. 3 (2017)
       
  • Nickel–molybdenum and cobalt–molybdenum sulfide hydrogenation and
           hydrodesulphurization catalysts synthesized in situ from bimetallic
           precursors
    • Authors: N. N. Petrukhina; I. A. Sizova; A. L. Maksimov
      Pages: 247 - 256
      Abstract: Unsupported nickel–molybdenum and cobalt–molybdenum sulfide catalysts are synthesized via the in situ decomposition of water-soluble bimetallic precursors in a hydrocarbon feedstock using nickel–molybdenum and cobalt–molybdenum complexes with citric, oxalic, succinic, glutaric, and tartaric acids as precursors. The sulfide catalysts are characterized by means of transmission electron microscopy and X-ray photoelectron spectroscopy. The catalyst activity in the hydrogenation of bicyclic aromatic hydrocarbons and the hydrodesulfurization of dibenzothiophene is studied. The effect the composition of the precursor solution in the hydrocarbon feedstock emulsion has on the activity of the resulting catalyst is determined. It is shown that the activity reaches high values even after 1 h of reaction. The hydrogenation of mono-, di-, and trimethylnaphthalenes and ethylnaphthalene is studied. The optimum promoter-to-molybdenum ratio (0.25: 1) is found. It is shown that the catalyst activity does not fall during recycling, due to the elimination of the negative effect of water contained in the emulsion, which results in oxidation of the catalyst surface. After the second reaction cycle, the catalyst particles are longer and have a greater number of MoS2 layers than the respective parameters of the catalyst particles after the first cycle. XPS shows that the content of oxygen on the catalyst’s surface falls during recycling, while the fraction of metals in the sulfide environment and the sulfur in the sulfide state grows.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030102
      Issue No: Vol. 9, No. 3 (2017)
       
  • Preparing bioethanol from oat hulls pretreated with a dilute nitric acid:
           Scaling of the production process on a pilot plant
    • Authors: O. V. Baibakova; E. A. Skiba; V. V. Budaeva; G. V. Sakovich
      Pages: 257 - 263
      Abstract: The full cycle of bioethanol production from pretreated oat hulls is scaled for a pilot plant. The one-stage pretreatment of oat hulls with a dilute nitric acid at atmospheric pressure is scaled for a 250-L reactor. The total amount of hydrolysable polysaccharides in the resulting substrate is 87.2%. Using the commercially available enzyme preparations CelloLux-A and BrewZyme BGX and the industrial strain BKPM Y-1693 of Saccharomyces cerevisiae yeast, the process of enzymatic hydrolysis and alcoholic fermentation is successfully scaled for a 63-L reactor. The scaling factor is 1: 400. Bioethanol is obtained with a high yield of 17.9 daL/t. After rectification, the test sample of bioethanol meets the standards for high-purity alcohol from food raw materials according to the mass concentration of aldehydes, esters, and by the content of methanol.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030023
      Issue No: Vol. 9, No. 3 (2017)
       
  • New methods for the one-pot processing of polysaccharide components
           (cellulose and hemicelluloses) of lignocellulose biomass into valuable
           products. Part 2: Biotechnological approaches to the conversion of
           polysaccharides and monosaccharides into the valuable industrial chemicals
           
    • Authors: K. N. Sorokina; Yu. V. Samoylova; A. V. Piligaev; Uthandi Sivakumar; V. N. Parmon
      Pages: 264 - 269
      Abstract: Part 2 of the review discusses modern processes for biotechnological conversion of lignocellulosic biomass into the valuable chemicals. It also recognizes the new approaches toward the development of more efficient enzymes for the depolymerization of biomass and the properties of the microorganisms employed in the fermentation of the biomass-derived sugars. Various biotechnological approaches to the fermentation of the depolymerized biomass products are described, including SHF, SSF, NSSF, SSFF, SSCF, and CBP. It is demonstrated that that the main tendencies for development of the new technologies for biotechnological biomass processing are the application of genetic engineering, synthetic biology and reduction of the number of processing steps. Application of one-pot processing of lignocellulosic biomass is promising for development of the new and efficient manufacturing technologies for production of valuable chemicals.
      PubDate: 2017-07-01
      DOI: 10.1134/s2070050417030126
      Issue No: Vol. 9, No. 3 (2017)
       
 
 
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