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Glycerol Etherification by tert-Butanol Catalyzed by Sulfonated Carbon Catalyst  [PDF]
Jidon Janaun,Naoko Ellis
Journal of Applied Sciences , 2010,
Abstract: The recent discovery of sulfonated carbon catalyst made from sugar attracts attention owing to its renewable source. The sulfonated carbon catalyst shows higher reactivity on esterification and transesterification reactions over the conventional solid acid catalysts such as nobic acid and amberlyst. These findings are remarkable because the sulfonated carbon catalyst has a surface area much smaller than any other solid acid catalysts tested for esterification and transesterification reactions. This study reports the characteristics of the sulfonated carbon catalyst and its reactivity on glycerol etherification by tert-butanol. Sulfonated carbon catalyst was prepared by sulphonation of the sugar char, prepared by pyrolyzing sugar (D-glucose) at 400°C for 15 h under nitrogen flow in a tube furnace. The catalyst was characterized by specific surface area, thermo-gravimetric analysis, FT-IR and total acidity, which showed that the sulfonated carbon catalyst has a surface area of less than 1 m2 g-1 and decomposed under inert gas at around 236°C. The catalyst has a total acidity of 4 mmol g-1, mainly contributed by -SO3 moiety as indicated by the FT-IR analysis. Etherification sample analyzed on GC-MS showed the presence of mono-glyceryl ethers isomers and di-glyceryl ether isomers; however, tri-glyceryl ether was not detected. The capability of the catalyst to promote the production of glyceryl ethers is a new application of the newly discovered sulfonated carbon catalyst; however, more experiments are required to elucidated catalyst reactivity, stability and selectivity under different reaction conditions. Di-glyceryl ethers are useful products in many applications such as biodiesel fuel additives.
Toughening of a Carbon-Fibre Composite Using Electrospun Poly(Hydroxyether of Bisphenol A) Nanofibrous Membranes Through Inverse Phase Separation and Inter-Domain Etherification  [PDF]
Kevin Magniez,Thomas Chaffraix,Bronwyn Fox
Materials , 2011, DOI: 10.3390/ma4111967
Abstract: The interlaminar toughening of a carbon fibre reinforced composite by interleaving a thin layer (~20 microns) of poly(hydroxyether of bisphenol A) (phenoxy) nanofibres was explored in this work. Nanofibres, free of defect and averaging several hundred nanometres, were produced by electrospinning directly onto a pre-impregnated carbon fibre material (Toray G83C) at various concentrations between 0.5 wt % and 2 wt %. During curing at 150 °C, phenoxy diffuses through the epoxy resin to form a semi interpenetrating network with an inverse phase type of morphology where the epoxy became the co-continuous phase with a nodular morphology. This type of morphology improved the fracture toughness in mode I (opening failure) and mode II (in-plane shear failure) by up to 150% and 30%, respectively. Interlaminar shear stress test results showed that the interleaving did not negatively affect the effective in-plane strength of the composites. Furthermore, there was some evidence from DMTA and FT-IR analysis to suggest that inter-domain etherification between the residual epoxide groups with the pendant hydroxyl groups of the phenoxy occurred, also leading to an increase in glass transition temperature (~7.5 °C).
Synthesis of Carbon Nanotubes of Few Walls Using Aliphatic Alcohols as a Carbon Source  [PDF]
Elsa G. Ordo?ez-Casanova,Manuel Román-Aguirre,Alfredo Aguilar-Elguezabal,Francisco Espinosa-Maga?a
Materials , 2013, DOI: 10.3390/ma6062534
Abstract: Carbon nanotubes with single and few walls are highly appreciated for their technological applications, regardless of the limited availability due to their high production cost. In this paper we present an alternative process that can lead to lowering the manufacturing cost of CNTs of only few walls by means of the use of the spray pyrolysis technique. For this purpose, ferrocene is utilized as a catalyst and aliphatic alcohols (methanol, ethanol, propanol or butanol) as the carbon source. The characterization of CNTs was performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The study of the synthesized carbon nanotubes (CNTs) show important differences in the number of layers that constitute the nanotubes, the diameter length, the quantity and the quality as a function of the number of carbons employed in the alcohol. The main interest of this study is to give the basis of an efficient synthesis process to produce CNTs of few walls for applications where small diameter is?required.
Novel Ni-Co-Mo-K Catalysts Supported on Multiwalled Carbon Nanotubes for Higher Alcohols Synthesis  [PDF]
Venkateswara Rao Surisetty,Janusz Kozinski,Ajay Kumar Dalai
Journal of Catalysts , 2013, DOI: 10.1155/2013/942145
Abstract: Alkali-promoted Ni-Co-Mo catalysts supported on multiwalled carbon nanotubes (MWCNTs) were prepared using 9?wt% K, 4.5?wt% Co, and 15?wt% Mo, whereas Ni content was varied from 0 to 6?wt%. The catalysts were extensively characterized and studied for higher alcohols synthesis from synthesis gas. Alkali-promoted trimetallic catalyst with 3?wt% Ni showed the highest total alcohols yield of 0.284?gm/(gm of cat./h), ethanol selectivity of 20%, and higher alcohols selectivity of 32% at 330°C and 9.0?MPa using gas hourly space velocity (GHSV) of 3.8?m3 (STP)/kg of catalyst/h and H2 to CO molar ratio of 1.25. 1. Introduction Ethanol has been used as an additive for reformulated gasoline as unleaded gasoline has become the standard, and short ether compounds (MTBE, ETBE, etc.) have been banned as gasoline octane continues to improve in North America [1]. The catalytic conversion of syngas to ethanol, and other higher alcohols, is generally recognized as an interesting route for the production of clean fuels and petrochemical feedstocks from coal, natural gas, and hydrocarbon wastes via gasification [2]. The catalysts for higher alcohol synthesis (HAS) are divided into two main groups based on the product distribution [3]. Alkali-doped high-temperature ZnCrO-based and low-temperature Cu-based catalysts produce mainly methanol and higher branched alcohols [4, 5]. Methanol synthesis catalysts modified with Fischer-Tropsch (FT) elements and modified Mo-catalysts are the second group of HAS catalysts. These catalysts yield a series of linear primary alcohols and gaseous hydrocarbons both with Anderson-Schulz-Flory (ASF) carbon number distribution [6, 7]. Comparatively, molybdenum-sulfide-based catalysts showed a high proportion of higher alcohols at lower pressure and high temperature. MoS2-based catalysts can tolerate sulfur and coke-buildup as a result of higher alcohols synthesis. When MoS2 is promoted with K2CO3, the same performance of the catalysts is achieved at a significantly lower temperature [8]. The alkali-promoted MoS2 catalysts promoted with Co showed high activity to alcohols and can also produce alcohols with a variable ratio of methanol to higher alcohols by changing the operating conditions [9, 10]. The CO hydrogenation was studied over K/Co/Mo/A12O3 and K/Co/Mo/SiO2 catalysts and found that all three elements are necessary for higher activity. Hydrocarbons and alcohols were produced in approximately equal amounts over both the catalysts [11]. Copromotion on alkali-modified MoS2 catalysts leads to the shrinking of MoS2 species, while Co exists
Preparation of Cyclic Urethanes from Amino Alcohols and Carbon Dioxide Using Ionic Liquid Catalysts with Alkali Metal Promoters  [PDF]
Shin-ichiro Fujita,Hiroshi Kanamaru,Hisanori Senboku,Masahiko Arai
International Journal of Molecular Sciences , 2006, DOI: 10.3390/i7100438
Abstract: Several ionic liquids were applied as catalysts for the synthesis of cyclicurethanes from amino alcohols and pressurized CO2 in the presence of alkali metalcompounds as promoters. A comparative study was made for the catalytic performanceusing different ionic liquids, substrates, promoters, and pressures. The optimum catalyticsystem was BMIM-Br promoted by K2CO3, which, for 1-amino-2-propanol, produced cyclicurethane in 40% yield with a smaller yield of substituted cyclic urea and no oligomericbyproducts. For other amino alcohols, cyclic urethanes, cyclic ureas, and/or undesiredbyproducts were produced in different yields depending on the substrates used. Possiblereaction mechanisms are proposed.
Etherification of glycerol with benzyl alcohol catalyzed by solid acids
Silva, Camila R. B. da;Gon?alves, Válter L. C.;Lachter, Elizabeth R.;Mota, Claudio J. A.;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009000200002
Abstract: in this work we present the results of glycerol etherification with benzyl alcohol, catalyzed by different solid acids. the mono-benzyl-glycerol ether was the main product in the reactions catalyzed by β zeolite and amberlyst-35 acid resin, whereas di-benzyl-ether was formed in higher yield with the use of p-toluene-sulfonic acid and k-10 montmorillonite as catalyst. niobic acid was inactive in this reaction. the porous structure of the zeolite impaired the formation of di and tri-benzyl-glycerol ethers.
Recent advances in the iron-catalyzed C-C bond formation via polar reactions of alcohols with carbon-centered nucleophiles
XiaoJie Shang,ZhongQuan Liu
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5123-1
Abstract: We summarized here the recent developments in the iron-catalyzed C-C bond formation via the polar reactions of alcohols with various carbon-centered nucleophiles. It is composed of three sections according to the categories of the C-centered nucleophiles such as C(sp3), C(sp2), and C(sp).
Atmospheric chemistry of alcohols
Grosjean, Daniel;
Journal of the Brazilian Chemical Society , 1997, DOI: 10.1590/S0103-50531997000500002
Abstract: the atmospheric chemistry of alcohols, which are widely used as motor vehicle fuels (e.g. ethanol in brazil) and as industrial solvents, has been reviewed with focus on kinetic data and on reaction mechanisms. oxidation of alcohols in the atmosphere involves their reaction with the hydroxyl radical (oh). alcohol-oh reaction rate constants are presented for 33 saturated alcohols including monofunctional and difunctional compounds. the corresponding atmospheric half-lives are one week for methanol and t-butyl alcohol, 2.5 days for ethanol, and 8-15 h for other alcohols. laboratory studies of alcohol-oh reaction products are described and reaction mechanisms are outlined. major products are formaldehyde from methanol, acetaldehyde from ethanol, acetone from 2-propanol, 2-butanone and acetaldehyde from 2-butanol and acetone and formaldehyde from t-butyl alcohol. the reaction of oh with alcohols involves h-atom abstraction from c-h bonds; h-atom abstraction from the o-h bond is negligible. the alkyl radicals (r) and a-hydroxyalkyl radicals thus formed react with oxygen. this reaction involves addition for alkyl radicals (r + o2 ro2) and h-atom abstraction for a-hydroxyalkyl radicals (e.g. ethanol + oh ch3choh, ch3choh + o2 ho2 + ch3cho). the reaction sequence ethanol acetaldehyde peroxyacetyl nitrate (pan, ch3c(o)oono2) is described and is relevant to urban air pollution in brazil. recommendation is made to carry out additional product studies in order to develop a better understanding of the atmospheric chemistry of alcohols and of their role in on urban and regional air quality.
Microstructure of neat alcohols  [PDF]
Aurelien Perera,Franjo Sokolic,Larisa Zoranic
Physics , 2007, DOI: 10.1103/PhysRevE.75.060502
Abstract: Formation of microstructure in homogeneous associated liquids is analysed through the density-density pair correlation functions, both in direct and reciprocal space, as well as an effective local one-body density function. This is illustrated through a molecular dynamics study of two neat alcohols, namely methanol and \emph{tert}-butanol, which have a rich microstructure: chain-like molecular association for the former and micelle-like for the latter. The relation to hydrogen bonding interaction is demonstrated. The apparent failure to find microstructure in water -a stronger hydrogen bonding liquid- with the same tools, is discussed.
Infrared Absorption Spectra of Monohydric Alcohols  [PDF]
Irina Doroshenko,Valeriy Pogorelov,Valdas Sablinskas
Dataset Papers in Science , 2013, DOI: 10.7167/2013/329406
Abstract: FTIR spectra of homologous series of monohydric alcohols which belong to the class of partly ordered liquids were registered. The molecules of monohydric alcohols containing hydroxyl group are able to form hydrogen-bonded clusters in the condensed phase. The existence of clusters is clearly observed from the position and the contour of the stretch OH band in the vibrational spectra of liquid alcohols. In this work, the experimentally registered FTIR spectra of liquid n-alcohols from methanol to decanol are presented as well as the same spectra of methanol, ethanol, propanol, butanol, pentanol, and hexanol in gas phase. 1. Introduction The clustering phenomena and structural peculiarities of partly ordered liquids are of great interest in the scientific community. This interest is even growing in context of recent trends and developments in studies on modern multifunctional materials, heterogeneous systems, and nanotechnologies. Among such partly ordered liquids are monohydric alcohols that usually build broad variety of H-bond aggregates. They are quite simple and convenient models to investigate properties of molecular systems sized over the mesoscopic scale (~1–100?nm). The cause of cluster formation in alcohols is the intermolecular hydrogen bond. The vibrational spectra of liquid alcohols differ from their spectra in gas phase or in matrix by the absence of the vibrational band of free hydroxyl group vibrations. Instead of this, the red-shifted diffuse band, which is usually associated with the presence of molecular aggregations (clustering), is observed. However the mechanism of the diffuse band formation and its structure are still the unsolved problems. The importance of the problems connected with the alcohol clustering and structure and, in particular, with the mechanisms of the diffuse absorption band formation is reflected in the great number of experimental [1–9], theoretical [10–14], and combined works [15–19] published in the recent years. The properties of a great number of partly ordered liquids are determined mainly by the characteristics of the hydrogen bond network. Monohydric alcohols are the convenient objects for the investigation of such intermolecular interaction as hydrogen bond. In this work, we present the experimentally registered FTIR spectra of the homologous series of monohydric alcohols in liquid and gaseous states. 2. Methodology The experimental registration of the presented spectra was made in the laboratory of Fourier transform infrared absorption spectroscopy at the Physics Department of Vilnius University,
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