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  Subjects -> CHEMISTRY (Total: 841 journals)
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CHEMISTRY (593 journals)                  1 2 3 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
2D Materials     Hybrid Journal   (Followers: 8)
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26)
ACS Catalysis     Full-text available via subscription   (Followers: 34)
ACS Chemical Neuroscience     Full-text available via subscription   (Followers: 18)
ACS Combinatorial Science     Full-text available via subscription   (Followers: 23)
ACS Macro Letters     Full-text available via subscription   (Followers: 23)
ACS Medicinal Chemistry Letters     Full-text available via subscription   (Followers: 39)
ACS Nano     Full-text available via subscription   (Followers: 233)
ACS Photonics     Full-text available via subscription   (Followers: 11)
ACS Synthetic Biology     Full-text available via subscription   (Followers: 21)
Acta Chemica Iasi     Open Access   (Followers: 2)
Acta Chimica Sinica     Full-text available via subscription   (Followers: 1)
Acta Chimica Slovaca     Open Access   (Followers: 1)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access  
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Adsorption Science & Technology     Full-text available via subscription   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 50)
Advanced Science Focus     Free   (Followers: 3)
Advances in Chemical Engineering and Science     Open Access   (Followers: 55)
Advances in Chemical Science     Open Access   (Followers: 13)
Advances in Chemistry     Open Access   (Followers: 14)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Enzyme Research     Open Access   (Followers: 9)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 19)
Advances in Nanoparticles     Open Access   (Followers: 15)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Science and Technology     Full-text available via subscription   (Followers: 12)
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 2)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 68)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 14)
American Journal of Chemistry     Open Access   (Followers: 26)
American Journal of Plant Physiology     Open Access   (Followers: 14)
American Mineralogist     Hybrid Journal   (Followers: 14)
Analyst     Full-text available via subscription   (Followers: 40)
Angewandte Chemie     Hybrid Journal   (Followers: 224)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 213)
Annales UMCS, Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 3)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 3)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 4)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 8)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 15)
Anti-Infective Agents     Hybrid Journal   (Followers: 3)
Antiviral Chemistry and Chemotherapy     Hybrid Journal  
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Spectroscopy     Full-text available via subscription   (Followers: 23)
Applied Surface Science     Hybrid Journal   (Followers: 28)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 1)
Atomization and Sprays     Full-text available via subscription   (Followers: 4)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 2)
Avances en Quimica     Open Access   (Followers: 1)
Biochemical Pharmacology     Hybrid Journal   (Followers: 10)
Biochemistry     Full-text available via subscription   (Followers: 295)
Biochemistry Insights     Open Access   (Followers: 6)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9)
Bioinspired Materials     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 2)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 1)
Biomacromolecules     Full-text available via subscription   (Followers: 19)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 4)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 119)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 97)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 2)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 2)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 3)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 3)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 10)
Canadian Mineralogist     Full-text available via subscription   (Followers: 3)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 66)
Catalysis for Sustainable Energy     Open Access   (Followers: 7)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysts     Open Access   (Followers: 8)
Cellulose     Hybrid Journal   (Followers: 7)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 1)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 13)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 70)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 23)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 3)
Chemical Research in Toxicology     Full-text available via subscription   (Followers: 19)
Chemical Reviews     Full-text available via subscription   (Followers: 175)
Chemical Science     Open Access   (Followers: 22)
Chemical Technology     Open Access   (Followers: 16)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemical Week     Full-text available via subscription   (Followers: 8)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 57)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 26)
ChemInform     Hybrid Journal   (Followers: 8)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 6)
Chemistry & Biology     Full-text available via subscription   (Followers: 30)
Chemistry & Industry     Hybrid Journal   (Followers: 5)
Chemistry - A European Journal     Hybrid Journal   (Followers: 142)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 15)
Chemistry and Materials Research     Open Access   (Followers: 18)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry International     Hybrid Journal   (Followers: 2)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Materials     Full-text available via subscription   (Followers: 258)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 9)
Chemistry World     Full-text available via subscription   (Followers: 22)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
Chemosensors     Open Access  
ChemPhysChem     Hybrid Journal   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal  
CHIMIA International Journal for Chemistry     Full-text available via subscription   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 10)
Chromatographia     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Cogent Chemistry     Open Access  
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 10)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 7)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 18)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comprehensive Chemical Kinetics     Full-text available via subscription   (Followers: 2)
Comptes Rendus Chimie     Full-text available via subscription  
Comptes Rendus Physique     Full-text available via subscription   (Followers: 1)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 9)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 2)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 5)
Crystal Structure Theory and Applications     Open Access   (Followers: 3)
CrystEngComm     Full-text available via subscription   (Followers: 12)
Current Catalysis     Hybrid Journal   (Followers: 2)
Current Metabolomics     Hybrid Journal   (Followers: 5)
Current Opinion in Colloid & Interface Science     Hybrid Journal   (Followers: 9)
Current Research in Chemistry     Open Access   (Followers: 8)
Current Science     Open Access   (Followers: 58)
Dalton Transactions     Full-text available via subscription   (Followers: 22)
Detection     Open Access   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Dislocations in Solids     Full-text available via subscription  
Doklady Chemistry     Hybrid Journal  
Drying Technology: An International Journal     Hybrid Journal   (Followers: 4)
Eclética Química     Open Access   (Followers: 1)
Ecological Chemistry and Engineering S     Open Access   (Followers: 4)
Ecotoxicology and Environmental Contamination     Open Access  
Educación Química     Open Access   (Followers: 1)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5)
EJNMMI Radiopharmacy and Chemistry     Open Access  
Elements     Full-text available via subscription   (Followers: 2)
Environmental Chemistry     Hybrid Journal   (Followers: 8)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 4)
Environmental Science & Technology Letters     Full-text available via subscription   (Followers: 5)
Environmental Science : Nano     Partially Free   (Followers: 1)
Environmental Toxicology & Chemistry     Hybrid Journal   (Followers: 17)

        1 2 3 | Last

Journal Cover Biomass Conversion and Biorefinery
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   Partially Free Journal Partially Free Journal
   ISSN (Print) 2190-6815 - ISSN (Online) 2190-6823
   Published by Springer-Verlag Homepage  [2353 journals]
  • Thermochemical valorization of camelina straw waste via fast pyrolysis
    • Authors: H. Hernando; J. Fermoso; I. Moreno; J. M. Coronado; D. P. Serrano; P. Pizarro
      Pages: 277 - 287
      Abstract: Abstract The present work investigates the thermochemical valorization of camelina straw, which is a waste generated during the harvesting of Camelina sativa, an oilseed crop for the production of biodiesel or hydrotreated vegetable oil (HVO). In particular, it is focused on obtaining bio-oil via thermal or catalytic fast pyrolysis, which would be the first stage on a sequence of chemical processes for biofuel production. The catalytic interference of the inorganic matter present in the biomass was studied by preparing a batch of de-ashed camelina straw by washing with diluted nitric acid. Chemical analysis revealed this treatment effectively removed alkaline (K and Na) and alkaline earth (Ca and Mg) metals. Pyrolysis of de-ashed camelina straw led to higher mass and energy yields of bio-oil in water-free basis (bio-oil*), but with higher oxygen concentration. Catalytic pyrolysis over HZSM-5 was also studied in both raw and de-ashed feedstocks. This catalyst promoted mainly decarbonylation and decarboxylation reactions of the pyrolysis vapors, leading to much higher gas yields and lower of bio-oil*, but with better quality. Catalytic pyrolysis of untreated camelina straw exhibited a synergetic effect between both the inorganic matter and the external HZSM-5 catalyst, so that bio-oil* yield was the lowest (20 wt%) due to an extensive deoxygenation (18 wt% oxygen content), which resulted in the highest HHV obtained (37.3 MJ/kgdb). Significant differences were also found on the molecular composition of the bio-oils* with larger proportion of anhydro sugars when the biomass was de-ashed, while HZSM-5 strongly promoted the formation of oxygenated aromatics and aromatic hydrocarbons.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0262-x
      Issue No: Vol. 7, No. 3 (2017)
       
  • Biomass catalytic fast pyrolysis over hierarchical ZSM-5 and Beta zeolites
           modified with Mg and Zn oxides
    • Authors: Héctor Hernando; Inés Moreno; Javier Fermoso; Cristina Ochoa-Hernández; Patricia Pizarro; Juan M. Coronado; Jiří Čejka; David P. Serrano
      Pages: 289 - 304
      Abstract: Abstract Hierarchical ZSM-5 and Beta zeolites, loaded with MgO and ZnO, have been explored for the catalytic fast-pyrolysis of eucalyptus woodchips. These materials exhibit a high dispersion of the MgO or ZnO phases, which is probably due to the presence of a hierarchical porosity with both micro- and mesopores in the zeolitic supports. The incorporation of these metal oxides led to a significant reduction in the textural properties and to changes in the acidic properties of the parent zeolites. Thus, a decrease in the concentration of Brønsted acid sites was observed, which was accompanied by the generation of additional Lewis acid sites with medium strength. In addition, the incorporation of metal oxide promotes the formation of significant amount of basic sites, especially for the samples loaded with MgO. Catalytic fast pyrolysis experiments of eucalyptus woodchips were performed in a fixed bed reactor at 500 °C and atmospheric pressure under a nitrogen flow. In comparison with non-catalytic fast pyrolysis, the use of zeolitic catalysts caused a decrease in the bio-oil* (water free basis bio-oil) production due to enhanced formation of gases, as well as coke deposition on the catalyst. However, the quality of the bio-oil* was enhanced since the catalysts were able to decrease its oxygen content. In this way, h-ZSM-5-based catalysts showed a clearly deeper deoxygenation degree compared to those having h-Beta as support, with very low content of anhydro sugars and the formation of a significant amount of aromatics. Regarding the effect of the metal oxide phase, MgO-loaded samples provided bio-oil* with enhanced energy yields and lower oxygen content, probably due to the adequate balance of Lewis acid and basic sites. Likewise, significant differences were observed among the catalysts regarding the deoxygenation pathways and the compounds families present in the bio-oil*.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0266-6
      Issue No: Vol. 7, No. 3 (2017)
       
  • Towards first-principles based kinetic modeling of biomass fast pyrolysis
    • Authors: Arturo Gonzalez-Quiroga; Kevin M. Van Geem; Guy B. Marin
      Pages: 305 - 317
      Abstract: Abstract Biomass conversion to chemicals and fuels through fast pyrolysis shows great potential but requires a more fundamental approach for its deployment. To this end, molecular-based kinetic modeling is starting to play a central role in the prediction of the molecular composition of bio-oil. A molecular-level representation of biomass provides the start point for the generation of detailed pyrolysis reaction networks for both the condensed and the gas phases. Significant progress has been made for cellulose, glucose-based carbohydrates, and lignin, together with the incorporation of the catalytic effects of minerals. Ab initio techniques are widely used to discriminate between reaction mechanisms and to calculate kinetic parameters. Automatic kinetic model generation is expected to play an even more important role in fast pyrolysis as it does already today. Experimental techniques enabled to obtain intrinsic kinetics and to decouple the timescales between reaction kinetics and analytic techniques. This greatly benefits the improvement of detailed kinetic models. The prospects for achieving a first-principles based kinetic model of biomass fast pyrolysis are promising. However, significant work is still needed to couple condensed- and gas-phase reaction networks.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0251-0
      Issue No: Vol. 7, No. 3 (2017)
       
  • Bio-oil upgrading via vapor-phase ketonization over nanostructured FeO x
           and MnO x : catalytic performance and mechanistic insight
    • Authors: Eleni Heracleous; Dong Gu; Ferdi Schüth; James A. Bennett; Mark A. Isaacs; Adam F. Lee; Karen Wilson; Angelos A. Lappas
      Pages: 319 - 329
      Abstract: Abstract In this study, nanostructured FeO x and MnO x were prepared by two synthetic routes, nanocasting and hydrothermal, and evaluated for bio-oil upgrading via vapor-phase ketonization. Catalytic performance measurements in the ketonization of representative model compounds, acetic and propionic acid, at 335 °C showed high activity for the hydrothermal MnO x and nanocast FeO x (conversion >90%) with high selectivity to the respective ketones. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies followed by temperature-programmed thermogravimetric analysis (TGA) and MS showed that the reactive intermediates are bidentate acetate species that desorb as acetone over FeO x and unreacted acetic acid over MnO x (in contradiction to its associated catalysis). Powder X-ray diffraction and X-ray photoelectron spectroscopy analysis of used samples revealed that MnO2 was reduced to MnO during reaction. The relative surface concentrations of adsorbed acetate for the used MnO x catalysts (from DRIFTS) correlated with their corresponding acetic acid conversion (from ketonization studies), indicating that MnO is the active phase for acetic acid ketonization, with MnO2 a precursor which is reduced in situ at temperatures >300 °C. Vapor-phase ketonization of the aqueous phase of a real thermal bio-oil, produced from the fast pyrolysis of lignocellulosic biomass, was demonstrated successfully over MnO x prepared by the hydrothermal route, highlighting this as an attractive approach for the upgrading of pyrolysis bio-oils.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0268-4
      Issue No: Vol. 7, No. 3 (2017)
       
  • On the influence of Si:Al ratio and hierarchical porosity of FAU zeolites
           in solid acid catalysed esterification pretreatment of bio-oil
    • Authors: Amin Osatiashtiani; Begoña Puértolas; Caio C. S. Oliveira; Jinesh C. Manayil; Brunella Barbero; Mark Isaacs; Chrysoula Michailof; Eleni Heracleous; Javier Pérez-Ramírez; Adam F. Lee; Karen Wilson
      Pages: 331 - 342
      Abstract: Abstract A family of faujasite (FAU) zeolites with different Si:Al ratio, and/or hierarchical porosity introduced via post-synthetic alkaline desilication treatment, have been evaluated as solid acid catalysts for esterification pretreatments of pyrolysis bio-oil components. Acetic acid esterification with aliphatic and aromatic alcohols including methanol, anisyl alcohol, benzyl alcohol, p-cresol and n-butanol was first selected as a model reaction to identify the optimum zeolite properties. Materials were fully characterised using N2 porosimetry, ICP, XRD, XPS, FT-IR, pyridine adsorption, NH3 TPD, In-situ ATR and inverse gas chromatography (IGC). IGC demonstrates that the surface polarity and hence hydrophobicity of FAU decreases with increased Si:Al ratio. Despite possessing a higher acid site loading and acetic acid adsorption capacity, high Al-content FAU possess weaker acidity than more siliceous catalysts. Esterification activity increases with acid strength and decreasing surface polarity following the order FAU30>FAU6>FAU2.6. The introduction of mesoporosity through synthesis of a hierarchical HFAU30 material further enhances esterification activity through improved acid site accessibility and hydrophobicity. Methanol was the most reactive alcohol for esterification, and evaluated with HFAU30 for the pretreatment of a real pyrolysis bio-oil, reducing the acid content by 76% under mild conditions.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0254-x
      Issue No: Vol. 7, No. 3 (2017)
       
  • Hydrodeoxygenation of phenolics in liquid phase over supported MoO 3 and
           carburized analogues
    • Authors: Rune Lødeng; Chanakya Ranga; Tapas Rajkhowa; Vaios I. Alexiadis; Hilde Bjørkan; Svatopluk Chytil; Ingeborg H. Svenum; John Walmsley; Joris W. Thybaut
      Pages: 343 - 359
      Abstract: Abstract Catalytic hydrodeoxygenation (HDO) of mono-aromatic components of increasing structural and chemical complexity, represented by phenol (−OH), anisole (−OCH3), and guaiacol (−OH + −OCH3), was performed in a down-flow trickle-bed reactor. ZrO2 supported Mo oxide with nominal loadings of 7, 15, and 25 wt% Mo were prepared and carburized analogues were synthesized at two thermal severity levels in a mixture of 20% CH4 in H2. HDO performance was compared with ZrO2 and Al2O3 supported CoMo-oxide reference catalysts. Performance was studied in the temperature range 573–648 K and a pressure of 6 MPa at liquid hourly space velocities (LHSVs) of 0.25–4.9 greactant/gcat, h at a H2/phenolic molar ratio of ca. 108. The intermediate Mo loading oxide catalysts showed superior performance. The parent Mo oxides were also more active than their carburized analogues and dominating hydrogenolysis pathways gave similar products and distribution. Carburization caused structural changes by reduction of MoO3 and formation of minor amounts of surface carbon. The weak hydrogenation activity did not change significantly. Reaction pathways were elucidated and ca. 100% selectivity to non-oxygenates in a wide conversion range was obtained from phenol. Anisole HDO was proceeding with ca. 85% selectivity to non-oxygenates. Structural complexity of guaiacol was causing even less efficient deoxygenation with a selectivity to non-oxygenates of only 5–10%. Catalysts were characterized by, N2-BET, CO-chemisorption, ICP-OES, XRD, TPR, XPS, (S)TEM-EDX, combustion-IR, and correlated to kinetic performance.
      PubDate: 2017-09-01
      DOI: 10.1007/s13399-017-0252-z
      Issue No: Vol. 7, No. 3 (2017)
       
  • Optimization of endoglucanase production from Trichoderma harzianum strain
           HZN11 by central composite design under response surface methodology
    • Authors: Zabin K. Bagewadi; Sikandar I. Mulla; Harichandra Z. Ninnekar
      Abstract: Abstract The utilization of abundantly available lignocellulosic biomass requires an efficient cellulolytic enzyme system. Evaluation of an efficient microbial system is a crucial part for the development of useful enzyme production in an industrial process. The present study reports the production of cellulolytic enzymes from various lignocellulosic biomasses by Trichoderma harzianum strain HZN11 characterized by 18S rDNA sequencing. The organism revealed a well-balanced cellulolytic complex of enzyme production (endoglucanase 30.32 U g−1, exoglucanase 15.08 U g−1, FPase 5.56 U g−1, cellobiase 17.92 U g−1, β-glucosidase 11.21 U g−1, and xylanase 1740 U g−1) from sweet sorghum bagasse under solid-state fermentation. Statistical optimization by Plackett–Burman design constituting of 12 experimental runs at two levels of seven independent variables revealed the significant effect of four variables, namely, protease peptone, lactose, MgSO4·7H2O, and K2HPO4 on endoglucanase production at 95% confidence level with R 2=97.68%. Response surface methodology using central composite design was employed with 31 experimental runs at 5 levels with 4 significant independent variables. The responses in the form of contour and 3D plots showed significant interaction effects. Significant interactions existed between the variables at p < 0.05 with R 2=97.3%. The model generated through these designs was validated giving a 2.31-fold increase in endoglucanase production. The isolated T. harzianum strain HZN11 produced an efficient pool of cellulolytic enzymes which is essential for efficient hydrolysis of biomass. The strain HZN11 also possessed a significant capability of cellobiase production which is usually deficient in other strains. Higher yields of endoglucanase could be employed for bioethanol production.
      PubDate: 2017-08-30
      DOI: 10.1007/s13399-017-0285-3
       
  • Methyl β -cyclodextrin as a booster for the extraction for Olea europaea
           leaf polyphenols with a bio-based deep eutectic solvent
    • Authors: Vassilis Athanasiadis; Spyros Grigorakis; Stavros Lalas; Dimitris P. Makris
      Abstract: Abstract A novel deep eutectic solvent (DES) with optimised composition was used to evaluate the effect of methyl β-cyclodextrin (CD) on the efficiency of polyphenol extraction from Olea europaea leaves (OLLs). The process developed was based on a 23 full-factorial design and response surface methodology to assess the simultaneous effect of CD concentration (C CD), liquid-to-solid ratio (R L/S ) and temperature (T). Under optimised conditions (C CD = 9%, R L/S = 40 mL g−1, T = 51 °C), the yield in total polyphenols (Y TP) was 116.65 ± 3.60 mg gallic acid equivalents per g dry weight. This value was significantly higher than that determined for the extraction performed with 60% aqueous ethanol. The extraction kinetics also showed that the extraction rate was slowed down in the presence of CD, yet the higher extraction capacity of the DES/CD medium was confirmed. Characterisation of the extracts obtained with DES/CD and DES by means of liquid chromatography-mass spectrometry demonstrated that there was no selective extraction of any particular polyphenol, suggesting that CD acted merely as an extraction booster.
      PubDate: 2017-08-24
      DOI: 10.1007/s13399-017-0283-5
       
  • Characterization of fat and biodiesel from mango seeds using 1 H NMR
           spectroscopy
    • Authors: Emmanuel Damilano Dutra; Thaysa Araujo de Lima; Jéssica Laís de Oliveira Souza; Joanna Gabriela Vicente Silva; Kátia Aparecida da Silva Aquino; Fabiana da Silva Aquino; Clecio Souza Ramos; Rômulo Simões Cezar Menezes
      Abstract: Abstract The investigation of processes to use oil-rich organic wastes to generate biodiesel is an important research area nowadays. In this respect, quantifying oil/fat and biodiesel with less labor demanding analytical tools such as proton nuclear magnetic resonance (1H NMR) can provide faster and more accurate acquisition of the chemical quality parameters of the organic samples. In the present study, the fat obtained from mango seed kernel (MSK) and its biodiesel were investigated using 1H NMR spectra to identify its physicochemical parameters. The results indicate that MSK fat shows high oxidative stability, and the biodiesel produced from MSK fat was compatible with European (EN 14214) and Brazilian (RANP 07/08) standards. The 1H NMR technique was efficient for providing the chemical parameters of MSK fat and its biodiesel without the need of any pretreatment. In addition, complementary analysis was performed to determine the MSK biodiesel quality.
      PubDate: 2017-08-24
      DOI: 10.1007/s13399-017-0286-2
       
  • Special thematic issue in “Biomass Conversion and Biorefinery”
           “Advances in catalytic biomass fast pyrolysis and bio-oil upgrading”
    • Authors: Eleni Heracleous; Angelos Lappas; David Serrano
      PubDate: 2017-08-23
      DOI: 10.1007/s13399-017-0284-4
       
  • Dilute acid hydrolysis of p -cresol-impregnated wood meal
    • Authors: Tomoyuki Hata; Hiroshi Nonaka
      Abstract: Abstract Dilute acid hydrolysis is typically conducted on wood to hydrolyze cellulose and hemicellulose into their compositional sugars, furfurals, or organic acids. However, lignin obtained in this process, also called hydrolysis lignin, cannot be generally used as a functional material. To overcome uncontrolled self-condensation of lignin, wood meal was impregnated with a small amount of p-cresol, and then, acid hydrolysis was performed with 1.1% sulfuric acid at 180 °C for 60 min. The cresol hardly changed the main products in the hydrolysate: glucose, formic acid, and levulinic acid. Much larger amount of lignin was extracted from the hydrolysis residue with tetrahydrofuran or by soda cooking than in the process without p-cresol impregnation. It seemed that the impregnated p-cresol was covalently bonded to lignin during acid hydrolysis and successfully prevented the self-condensation of lignin molecules, contributing improvement of the solubility of the resultant lignin in organic solvents or aqueous sodium hydroxide. Our hydrolysis process balances the valorization of carbohydrate with that of lignin.
      PubDate: 2017-08-23
      DOI: 10.1007/s13399-017-0282-6
       
  • Investigation of the textural and adsorption properties of activated
           carbon from HTC and pyrolysis carbonizates
    • Authors: Catalina Rodríguez Correa; Chatri Ngamying; Dietmar Klank; Andrea Kruse
      Abstract: Bamboo was converted into a microporous activated carbon (AC) following either a one- or a two-step activation process with KOH. The main objective was to analyze the influence of the carbonization process (pyrolysis and hydrothermal carbonization (HTC)) and mixing method of KOH (dry mixing or impregnation) on the AC textural properties as well as on the adsorption capacity of water-soluble pollutants and hydrogen (H2) storage. The highest AC yields were obtained after a two-step activation process. These ACs presented the largest surface areas (2000–2500 m2 g−1) and the best adsorption capacities not only in aqueous media but also of H2. The type of carbonization process did not have a significant effect on yield and adsorption capacities, but it did affect the surface area and pore size distribution. HTC led to ACs with a larger total pore volume than ACs from pyrolysis, but the microporous surface area was smaller. KOH impregnation led to slightly but significantly higher yields than mixing KOH dry; yet, the textural and adsorption properties were not significantly improved. KOH impregnation led to slightly but significantly higher yields than mixing KOH dry; yet, the surface area and pore size distribution as well as adsorption properties were not significantly improved. H2 adsorption capacity was highest for ACs from impregnated hydrochar, followed closely by ACs from pyrochars. Graphical abstract ᅟ
      PubDate: 2017-07-29
      DOI: 10.1007/s13399-017-0280-8
       
  • Analysis of pyrolysis characteristics and kinetics of Euphausia superba
           shell waste using TG-FTIR and distributed activation energy model
    • Authors: Yuhui Ma; Jing Wang; Yushan Zhang
      Abstract: Abstract Pyrolysis of Euphausia superba shell waste (ESW) was investigated by using a thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer (TG-FTIR). The kinetic parameters of pyrolysis reactions were obtained via the distributed activation energy model (DAEM). Experimental results showed that the temperature at which the highest weight loss rate occurred increased from 280 to 315 °C as the heating rate increased from 5 to 30 °C min−1. Almost all the volatiles were evolved between 300 and 350 °C, while CH4 and aliphatic C–H were also produced at higher-temperature regions. A large amount of CO2 was generated above 650 °C by the decomposition of carbonates, and it can be further reduced to CO by ESW char. CO2 was the main non-condensable product, and ketones were the dominating condensable products. The activation energy of pyrolysis reactions increased from 79 to 392 kJ mol−1 for conversion rates 0.13 to 0.54. The linear relationship between the natural logarithm of the frequency factor and activation energy was also established. The activation energy approximately followed Gaussian distribution, and the mean activation energy was 162 kJ mol−1.
      PubDate: 2017-07-25
      DOI: 10.1007/s13399-017-0281-7
       
  • Characteristics of hydrochar and hydrothermal liquid products from
           hydrothermal carbonization of corncob
    • Authors: Kamonwat Nakason; Bunyarit Panyapinyopol; Vorapot Kanokkantapong; Nawin Viriya-empikul; Wasawat Kraithong; Prasert Pavasant
      Abstract: Abstract Corncob (CC) was converted to renewable fuel resource by hydrothermal carbonization (HTC). HTC was performed by varying process temperature (160–200 °C), residence time (1–3 h), and biomass to water ratio (BTW) (1:5 to 1:15). The properties of hydrochar were significantly enhanced where the fixed carbon and carbon content of hydrochar increased at about 24.9 and 83.7% from original contents in CC, respectively. The calorific values and yield of hydrochar were between 19.3–23.5 MJ/kg and 50.1–58.6%. The optimal condition for the production of hydrochar as solid fuel was determined at 200 °C, 3 h residence time, and BTW of 1:5 with maximum energy yield of 68.74%. In addition, hydrothermal liquid was characterized where volatile fatty acid, furfural, furfuryl alcohol, and hydroxymethylfurfural were the most abundant compositions with their highest yields of 17.3, 11.5, 7.9, and 5.1%, respectively. Process temperature was the most influencing variable on product properties and characteristics. The results suggested that corncob has high potential as a source for solid fuel and valuable platform chemicals.
      PubDate: 2017-07-22
      DOI: 10.1007/s13399-017-0279-1
       
  • Exploring the stability and reactivity of Ni 2 P and Mo 2 C catalysts
           using ab initio atomistic thermodynamics and conceptual DFT approaches
    • Authors: Ángel Morales-García; Junjie He; Pengbo Lyu; Petr Nachtigall
      Abstract: Abstract The stability and reactivity of Mo2C and Ni2P surfaces with different terminations are systematically investigated by means of ab initio atomistic thermodynamics and conceptual DFT approaches as a function of the chemical potential (μ). Five surfaces labeled as (001)-Mo-1, (110)-Mo/C, (001)-Ni3P2, (001)-Ni3P2-P, and (001)-Ni3P1 emerge as the most stable ones for Mo2C and Ni2P catalysts depending on μ C and μ P, respectively. The Fukui function, a reactivity descriptor, reveals that the metal atoms interact preferentially with nucleophilic adsorbates such as H2S. Here, our study predicts that a high concentration of C and P atoms on the surface reduces the catalytic activity where nucleophilic species are involved. The qualitative agreement between the nucleophilic Fukui function (f +) and the adsorption energies indicates that the Ni2P catalyst is, in general, more reactive than Mo2C catalyst. This study may help to improve and optimize the catalytic processes, such as the hydrogenations HDO and HDS, where Mo2C and Ni2P catalysts are involved.
      PubDate: 2017-07-12
      DOI: 10.1007/s13399-017-0278-2
       
  • Alkaline hydrogen peroxide pretreatment of lignocellulosic biomass: status
           and perspectives
    • Authors: Emmanuel Damilano Dutra; Fernando Almeida Santos; Bárbara Ribeiro Alves Alencar; Alexandre Libanio Silva Reis; Raquel de Fatima Rodrigues de Souza; Katia Aparecida da Silva Aquino; Marcos Antônio Morais Jr; Rômulo Simões Cezar Menezes
      Abstract: Abstract Lignocellulosic biomass is a renewable and abundant resource that is suitable for the production of bio-based materials such as biofuels and chemical products. However, owing to its complex chemical composition, it requires a process that enhances the release of sugars. Pretreatment is an essential stage in increasing the efficiency of enzymatic hydrolysis of lignocellulosic biomass. The most widely used pretreatment methods operate at high temperatures (160–290 °C) and pressures (0.69 to 4.9 MPa) and generate biological growth inhibitors such as furfural and hydroxymethylfurfural (HMF). Thus, there has been a growing need to adopt new approaches for an effective pretreatment that operates at ambient temperature and pressure and reduces the generation of inhibitors. Among these methods, alkaline hydrogen peroxide (AHP) is notable because it is effective for a wide range of lignocellulosic biomass concentrations, and can provide a high degree of enzymatic hydrolysis efficiency. However, few results have been discussed in the literature. Given this, the aim of this study was to investigate the use of alkaline hydrogen peroxide (AHP) as an oxidative pretreatment agent to improve the efficiency of enzymatic hydrolysis for different types of biomass and examine the key areas of the pretreatment. Finally, there is a discussion of the challenges facing a large-scale application of this method.
      PubDate: 2017-07-06
      DOI: 10.1007/s13399-017-0277-3
       
  • One-vessel saccharification and fermentation of pretreated sugarcane
           bagasse using a helical impeller bioreactor
    • Authors: Raul Alves de Oliveira; Leda Maria Fortes Gottschalk; Suely Pereira Freitas; Elba Pinto da Silva Bon
      Abstract: Abstract The effect of Tween® 80 and the cellulase load, on the enzymatic hydrolysis of hydrothermally pretreated sugarcane bagasse (HPSB), was evaluated in shake flask experiments, using experimental design. The optimized conditions were further applied in a second set of shake flask experiments to study the effect of the biomass load. The overall optimum parameters, e.g., 6.9% Tween® 80, 15 FPU/g glucan, and 150 g/L (dry HPSB), were used in hydrolysis experiments carried out in a laboratory-scale bioreactor equipped with a helical impeller. After a 48 h reaction time, 60% of the HPSB glucan content was hydrolyzed into glucose. The same bioreactor and hydrolysis conditions were used for one-vessel saccharification and fermentation experiments as follows: 150 g/L (dry HPSB) was hydrolyzed at 50 °C and 150 rpm for either 24 or 48 h, followed by the bioreactor’s temperature and mixing decrease to 30 °C and 90 rpm for ethanol fermentation by Saccharomyces cerevisiae. Experiments resulted in ethanol yields of 48 or 52%, for hydrolysis time of 24 or 48 h, respectively, taking into account the HPSB glucan content. The best ethanol productivity, for the overall process of 0.51 g/L.h, was achieved for the 24 h hydrolysis time.
      PubDate: 2017-06-29
      DOI: 10.1007/s13399-017-0272-8
       
  • Hydrothermal carbonization of food waste: simplified process simulation
           model based on experimental results
    • Authors: Kyle McGaughy; M. Toufiq Reza
      Abstract: Abstract Hydrothermal carbonization (HTC) was performed on homogenized food waste (FW) in a batch reactor at 200, 230, and 260 °C for 30 min. Solid product, called hydrochar, was characterized by means of ultimate analysis, proximate analysis, higher heating value (HHV), and ash content. On the other hand, liquid products were analyzed by inductively coupled plasma (ICP), total carbon, and pH. HHV of FW was increased from 25.1 to 33.1 MJ kg−1 by HTC. Ash content is less than 3% for hydrochars as well as the raw FW. Fixed carbon increased from 18.8 to 22.4% with the increase of HTC temperature. Fuel characteristics indicate hydrochar as a potential solid fuel and carbon storage. Therefore, a simplified simulation model was created for a continuous process that performs HTC of 1 t of FW per day. It was determined that HTC of food waste has potential to be a viable process for the production of solid fuel, primarily due to ease of drying product char.
      PubDate: 2017-06-28
      DOI: 10.1007/s13399-017-0276-4
       
  • Catalytic hydroprocessing of lignin β-O-4 ether bond model compound
           phenethyl phenyl ether over ruthenium catalysts
    • Authors: B. Gomez-Monedero; J. Faria; F. Bimbela; M. P. Ruiz
      Abstract: Abstract The catalytic hydroprocessing of phenethyl phenyl ether (PPE), a model compound of one of the most significant ether linkages within lignin structure, β-O-4, has been studied. Reactions were carried out using two ruthenium-based catalysts, supported on different materials: 3.8 wt.% Ru/C and 3.9 wt.% Ru/Al2O3. Aiming at studying the reaction mechanism, experiments were carried out at 150 °C and 25 bar in H2 atmosphere, with varying feed to catalyst mass ratios and reaction time. Differences between the relative importance of the steps of the mechanism were observed when using those two catalysts. The most significant finding was the predominance of the cleavage of Cβ-O bonds compared to the cleavage of the Caryl-O when using Ru/Al2O3 as catalyst; whereas with Ru/C, the two routes were nearly equivalent. It has been observed that the kinetic model describes the general tendencies of consumption and formation of the different products, but some over/under estimation of concentrations occurs. Finally, the effect of temperature was also explored by carrying out reactions at 100 and 125 °C, observing that decreasing temperature from 150 to 125 or 100 °C favored the dimer hydrogenation route versus the hydrogenolysis of the ether bonds.
      PubDate: 2017-06-24
      DOI: 10.1007/s13399-017-0275-5
       
  • Mono-, bi-, and tri-metallic Ni-based catalysts for the catalytic
           hydrotreatment of pyrolysis liquids
    • Authors: Wang Yin; Robbie H. Venderbosch; Songbo He; Maria V. Bykova; Sofia A. Khromova; Vadim A. Yakovlev; Hero J. Heeres
      Abstract: Abstract Catalytic hydrotreatment is a promising technology to convert pyrolysis liquids into intermediates with improved properties. Here, we report a catalyst screening study on the catalytic hydrotreatment of pyrolysis liquids using bi- and tri-metallic nickel-based catalysts in a batch autoclave (initial hydrogen pressure of 140 bar, 350 °C, 4 h). The catalysts are characterized by a high nickel metal loading (41 to 57 wt%), promoted by Cu, Pd, Mo, and/or combination thereof, in a SiO2, SiO2-ZrO2, or SiO2-Al2O3 matrix. The hydrotreatment results were compared with a benchmark Ru/C catalyst. The results revealed that the monometallic Ni catalyst is the least active and that particularly the use of Mo as the promoter is favored when considering activity and product properties. For Mo promotion, a product oil with improved properties viz. the highest H/C molar ratio and the lowest coking tendency was obtained. A drawback when using Mo as the promoter is the relatively high methane yield, which is close to that for Ru/C. 1H, 13C-NMR, heteronuclear single quantum coherence (HSQC), and two-dimensional gas chromatography (GC × GC) of the product oils reveal that representative component classes of the sugar fraction of pyrolysis liquids like carbonyl compounds (aldehydes and ketones and carbohydrates) are converted to a large extent. The pyrolytic lignin fraction is less reactive, though some degree of hydrocracking is observed.
      PubDate: 2017-06-03
      DOI: 10.1007/s13399-017-0267-5
       
 
 
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