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Byline: Harry Verelst Beyond Oil and Gas: The Methanol Economy, by George A. Olah, Alain Goeppert and G.K. Surya Prakash. Weinheim, Wiley-VCH, 2006. 290 pp. ISBN 3-527-31275-7

In the last few years, many reagents and protocols have been developed to allow for the efficient fluorofunctionalization of a diverse set of scaffolds ranging from alkanes, alkenes, alkynes, and (hetero)arenes. The concomitant rise of organofluorine chemistry and visible light‐mediated synthesis have synergistically expanded the fields and have mutually benefitted from developments in both fields. In this context, visible light driven formations of radicals containing fluorine have been a major focus for the discovery of new bioactive compounds. This review details the recent advances and progress made in visible light‐mediated fluoroalkylation and heteroatom centered radical generation. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction to fuels powered by renewable electricity is a potential clean strategy to replace fossil fuels and address climate change caused by increasing CO2 emissions. In this work, the electrocatalytic CO2 reduction process was briefly introduced; the latest literature on the electrocatalytic CO2 reduction to CO by cobalt phthalocyanine (CoPc) was summarized. The structure, catalytic activity, and improvement strategies of CoPc were analyzed in detail. Then, the possible mechanism for the electrocatalytic CO2 reduction to CO was elucidated. Finally, the challenges and possible solutions of cobalt-based catalysts in electrocatalytic CO2 reduction were discussed. We believe it will serve as an up-to-date reference for the design of more efficient and stable cobalt-based catalysts for CO2 reduction, providing new insights and perspectives for further development of excellent catalytic materials. [ABSTRACT FROM AUTHOR]

Cyclic ethylene carbonate is an essential compound in the industry with many uses. This compound can be produced by reaction of carbon dioxide as a greenhouse gas and ethylene epoxide. A toxic and expensive metal as a catalyst is mostly used for this reaction. So, introducing an inexpensive and metal-free catalyst for this reaction may be helpful. For this aim, we studied the carbon nanotube with the characteristic properties. The surface activity of the carbon nanotube was improved by substituting one carbon atom with a silicon atom for this reaction. In this work, we studied two possible reaction pathways for the reaction of carbon dioxide and ethylene epoxide on the surface of a silicon-doped carbon nanotube. We studied about the electrostatic potential surfaces to predict possible interactions and surface activity. Also, the thermodynamic parameters have been calculated for these processes. The calculated thermodynamic parameters show that the adsorption of these molecules on the silicon-doped carbon nanotube is exothermic, and the next steps of the reaction pathways are thermodynamically favoured. [ABSTRACT FROM AUTHOR]

CO2 conversion to value-added chemicals requires efficient catalytic CO2 reduction. Activation of CO2 using 14 phosphine–borane frustrated Lewis pair catalysts was done computationally using B3LYP-D3/6-31++G(d,p)/PCM/THF and M06-2X/6-311++G(d,p)/PCM/THF methods. We designed 14 catalysts, 12 of which exhibit better catalytic activity towards CO2 activation. Moreover, the catalytic mechanisms of compounds 12 and 4 were predicted, and they showed an efficient catalytic system for CO2 reduction to CO, HCHO and HCOOH. Catalysts 2, 3 and 4, with the same methylene linker, have activation energies of 20.5, 18.3 and 10.4 kcal/mol, respectively. This indicates that the catalytic activity of the compound is highly influenced by the ligand bound to borane and phosphine. Compound 4 with the CO2 activation energy of 10.4 kcal/mol is the most efficient catalyst for CO2 activation ever reported among phosphine–borane catalysts. The energy barriers for H2 activation with catalyst 12 (ΔG‡ = 26.6 kcal/mol) and 4 (ΔG‡ = 34.0 kcal/mol) are higher than the HCOOH releasing activation energy. The designed compounds will help to synthesise efficient metal-free phosphine–borane catalysts. Our results also indicate that phosphine–borane catalysts are promising candidates for CO2 reduction and direct hydrogenation. [ABSTRACT FROM AUTHOR]

Information about several papers discussed at the Burgenstock Conference 2010 on the branch of stereochemistry is presented. Recent developments in hydrogen bond-promoted asymmetric catalysis brought opportunities in organic synthesis. The conference featured several researchers including Herbert Mayr, G.K. Surya Prakash, and Viresh H. Rawal.

The application of gallium(III) trifluoromethanesulfonate (triflate, OTf) in Friedel-Crafts alkylation and acylation reactions is described. Gallium triflate was found to be an excellent catalyst for the adamantylation of toluene with 1-bromoadamantane, where its activity was compared to that of well-known rare earth metal triflates. As Ga(OTf)3 does not decompose in the presence of water the isopropylation of aromatics can be carried out with isopropyl alcohol in moderate to excellent yields. While acetylation provides moderate yields in selective reactions, benzoylation of aromatics takes place in good yields in a catalytic and non-stoichiometric reaction. The catalyst can easily be recovered from the reaction mixture and can be reused without loss of activity, demonstrating its effective and environmentally friendly recyclable character. [ABSTRACT FROM AUTHOR]

The process of CO2 hydrogenation into methanol has recently attracted more attention for reducing CO2, a main green-house gas in the atmosphere. In addition, methanol can be used as fuel or a basic chemical to satisfy the growing demand for energy in the world. In this study, the performance of NaA membrane reactor on the methanol yield and methanol selectivity obtained from the CO2 hydrogenation process was evaluated at different reaction conditions by varying the temperature, pressure, gas hourly space velocity (GHSV) and H2/CO2 ratio. The results show that the methanol yields and methanol selectivities obtained from the membrane reactor (MR) at all reaction conditions are higher than those from the traditional reactor (TR). The ratio of methanol yield in MR over methanol yield in TR are varied from 1.4 to 1.7 depending on the operating conditions. It is also observed that the use of membrane reactor is more efficient at low GHSV and the temperature in the range of 220–240°C. [ABSTRACT FROM AUTHOR]

The hydration reaction of α-pinene in the presence of natural clays treated with monochloroacetic acid as catalyst to obtain oxygenated compounds was studied. Catalysts were characterized using X-ray diffraction, differential thermal analysis, programmed thermal desorption of adsorbed pyridine, and infrared spectroscopic analysis of adsorbed pyridine to determine Brønsted and Lewis acid sites. Catalytic tests revealed that treatment of the natural clay with the acid improved the catalytic activity and the selectivity toward oxygenated products by increasing the acidity of the catalyst. The selectivity toward oxygenated compounds increased with the augment of the α-pinene conversion because of greater contact between water molecules with the remaining α-pinene molecules. The natural clay without treatment produced compounds resulting from α-pinene isomerization, whereas the treated clays produced alcohols and other products in addition to isomerization compounds. After a certain time, the α-terpineol was isomerized into cineols. Studies of the reusability of the JAL catalyst were performed (clay treated with monochloroacetic acid). As the number of reuses increased, the percent conversion decreased; however, the selectivity toward oxygenated compounds increased. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Polyethylene (PE) composite coatings were prepared on silicon substrate by electron-beam deposition (EBD) using mixed powders of low-density polyethylene and various dopants (i.e., initiator and inhibitor) as evaporated target. The structural and morphological behaviors of PE composite coatings were investigated in dependence of initiator and inhibitor by attenuated total reflectance-Fourier transform infrared spectroscopy and atomic force microscope. Free-radical polymerization and cationic polymerization could be observed in the formation process of PE composite coatings by EBD. The initiating system of AlCl3 and benzoyl peroxide as well as the inhibiting system of diphenylamine and hydroquinone used in EBD, in comparison with conventional synthesis methods, exhibited different effect on reaction mechanism of PE composite coatings. These results might contribute to the synthesis of polymer coatings with expectant molecule structure and controllable surface morphology. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The article discusses the synthesis of a novel single hybrid monomer combining a vinylether and trimethoxysilane groups in the same molecule through chemoselective hydrosilation. It was also subjected to ultraviolet (UV)-irradiation in the presence of a triarylsulfonium salt. A type II polyvinyl-polysilicate nanocomposite film resulted from the simultaneous occurrence of two acid-catalyzed processes. Parameters such as laminated conditions, UV irradiation equipment and film thickness were also investigated.

The reactions of free, size selected Au ( n = 1-3, 5, 7) and Ag clusters with CHBr as well as the photodissociation of the resulting complexes at 266 nm were studied in a radio frequency ion trap under multiple collision conditions. CHBr was found to interact more strongly with the gold clusters than with the silver clusters. All investigated metal clusters exhibited characteristic size dependent adsorbate coverages. Furthermore, the successive loss of methyl radicals was identified as a major thermal reaction channel of the adsorbed CHBr molecules. Photodissociation experiments were performed with the product complexes of the trimer clusters and revealed the strongly preferred light-induced fragmentation of AuBr and AgBr, respectively, over any other thermal reaction products. However, whereas in the case of the gold cluster complexes the bare Au was exclusively re-formed through laser irradiation, considerable photoinduced metal cluster fragmentation occurred in the case of AgBr. [ABSTRACT FROM AUTHOR]

Coadsorption effects of molecular hydrogen and small hydrocarbons, CH4 and C3H6, on free Au3 + and Au5 + were investigated in an octopole ion trap under multi-collision conditions. For hydrogen and methane the observations indicate that both molecules coadsorb on the same adsorption site, i.e., the same atom of the cluster. This type of molecular adsorption on free clusters is termed permissive coadsorption, in contrast to competitive coadsorption, in which two molecules compete for the same adsorption site. The latter case was observed for hydrogen and propylene: already trace amounts of propylene were able to completely saturate the clusters preventing the coadsorption of H2. The size dependent adsorbate coverage is discussed and implications on the cluster structure are deduced from time and temperature dependent reaction measurements. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemistry is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Chemistry is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gallium triflate catalyzed Beckmann rearrangement is described. Various aliphatic or aromatic amides are obtained from the corresponding ketoximes in good yields. Gallium triflate exhibits high catalytic activity for a wide variety of substrates. [ABSTRACT FROM AUTHOR]

Cyclohexane and methylcyclopentane isomerization were carried out under mild conditions using an ionic liquid consisting of n-butylpyridinium chloride and aluminum chloride as catalyst. The ionic liquid showed reasonably high catalytic activity in both reactions with a selectivity to corresponding products of 100%. In the case of cyclohexane isomerization, the thermodynamic equilibrium methylcyclopentane ⇌cyclohexane was almost achieved. For the reaction of cyclohexane isomerization, the kinetic study was performed, and the rate constants and the activation energy of the process were determined. [ABSTRACT FROM AUTHOR]

Superacidic trifluoromethanesulfonic acid-induced synthesis of 1-indanone and 1-tetralone derivatives through Friedel-Crafts cycli-acyalkylation of aromatics with unsaturated carboxylic acids was achieved. Depending on the reactant used, different substituted indanones and tetralones were obtained in moderate to good yields. [ABSTRACT FROM AUTHOR]