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141.
Alberto Albis Ever Ortiz Andrés Suárez Ismael Piñeres 《Journal of Thermal Analysis and Calorimetry》2014,115(1):275-283
The Amazonian rain forest is the source of several numbers of species in the world, some of those vegetal species have been carried to different places due to their utility. One of those species is the Thehobroma grandiflorum, pulp and seeds of which have several usages in the food industry, but the shell has no extensive use. One of the possibilities due to the nature of the material is the pyrolysis process for obtaining valuable products. Thermal analysis was studied for the biomass thermochemical conversion process under TG/MS techniques. Three different heating rates were used for the thermochemical process. A variety of hydrocarbon and oxygenated products with industrial importance were obtained. The kinetics of the evolved species was studied under three different models. DAEM model fit the thermogravimetric data with good agreement. The parameters obtained for the model agreed with the studied intensities of the MS data. Those ones that did not fit were due to possible gas-phase reactions between the compounds obtained. 相似文献
142.
The Reductive Dehydration of Cellulose by Solid/Gas Reaction with TiCl4 at Low Temperature: A Cheap,Simple, and Green Process for Preparing Anatase Nanoplates and TiO2/C Composites 下载免费PDF全文
Sandrine Plumejeau Dr. Matthieu Rivallin Prof. Stephan Brosillon Prof. André Ayral Dr. Laurent Heux Prof. Bruno Boury 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17262-17268
Metal oxides and metal oxide/carbon composites are entering the development of new technologies and should therefore to be prepared by sustainable chemistry processes. Therefore, a new aspect of the reactivity of cellulose is presented through its solid/gas reaction with vapour of titanium(IV) chloride in anhydrous conditions at low temperature (80 °C). This reaction leads to two transformations both for cellulose and titanium(IV) chloride. A reductive dehydration of cellulose is seen at the lowest temperature ever reported and results in the formation of a carbonaceous fibrous solid as the only carbon‐containing product. Simultaneously, the in situ generation of water leads to the formation of titanium dioxide with an unexpected nanoplate morphology (ca. 50 nm thickness) and a high photocatalytic activity. We present the evidence showing the evolution of the cellulose and the TiO2 nanostructure formation, along with its photocatalytic activity. This low‐temperature process avoids any other reagents and is among the greenest processes for the preparation of anatase and also for TiO2/carbon composites. The anisotropic morphology of TiO2 questions the role of the cellulose on the growing process of these nanoparticles. 相似文献
143.
Rebeca Infante Dr. Javier Nieto Prof. Dr. Celia Andrés 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(14):4375-4379
A highly efficient enantioselective addition of Me2Zn to α‐ketoesters, assisted by a chiral perhydro‐1,3‐benzoxazine ligand, is described. This novel catalytic system offers homogeneous elevated enantioselectivities in the preparation of α‐hydroxyesters that bear a quaternary stereocenter, with a minor dependence on electronic and steric effects when aromatic, heteroaromatic, or aliphatic α‐ketoesters are employed. The catalyst can be recovered and reused without loss of activity. 相似文献
144.
Viviana Heguaburu Hugo do Carmo Florencia Parpal María Eugenia Amorós Andrés González 《Tetrahedron letters》2017,58(18):1738-1741
The synthesis of 3-hydroxy-2-hexanone and 2,3-hexanediol, two components of the aggregation pheromone of several cerambycid species, is disclosed in here. Starting from 2-hexanone, through an α-hydroxylation using (diacetoxyiodo)benzene, 3-hydroxy-2-hexanone is obtained in good yield. Further reduction of this compound, gives 2,3-hexanediol in excellent yield. A study of the α-hydroxylation reaction of several alkylketones using an hypervalent iodine reagent is also disclosed in here. The synthesis of optically active compounds (R)- and (S)-3-hydroxy-2-hexanone was achieved starting from 2-hexanone with nitrosobenzene and l- and d-proline respectively, in several reaction media. 相似文献
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Ray L. Frost Yunfei Xi Ricardo Scholz Andrés López Fernanda M. Belotti Mário L. S. C. Chaves 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1526-1534
Abstract The metal lithium is very important in industry, including lithium batteries. An important source of lithium besides continental brines is granitic pegmatites as in Australia. Lithiophilite is a lithium and manganese phosphate with chemical formula LiMnPO4 and forms a solid solution with triphylite, its Fe analog, and belongs to the triphylite group that includes karenwebberite, natrophilite, and sicklerite. The mineral lithiophilite was characterized by chemical analysis and spectroscopic techniques. The chemical is: Li1.01(Mn0.60, Fe0.41, Mg0.01, Ca0.01)(PO4)0.99 and corresponds to an intermediate member of the triphylite-lithiophilite series, with predominance of the lithiophilite member. The mineral lithiophilite is readily characterized by Raman and infrared spectroscopy. 相似文献