bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygenates Synthesis – Homogeneous
Authors: Whyman Robin 
Published: February 2011

AbstractThe current status of direct (from CO/H2) and indirect (via methanol, formaldehyde, or methyl acetate) homogeneously catalyzed C1chemistry based routes for the selective production of the oxygenates methanol, ethanol, and ethylene glycol (including higher alcohols, diols, and acetate esters); acetic and propionic acid; ethyl and vinyl acetate; acetic anhydride; and methyl formate is described. While none of the direct synthesis gas based routes have been commercialized, largely because of low catalytic activities and extreme operating pressure requirements, indirect routes including the Co‐, Rh‐, and Ir‐catalyzed carbonylation of methanol to acetic acid and the Rh‐catalyzed carbonylation of methyl acetate to acetic anhydride, together with the coproduction of both, are well‐established commercial processes. The majority of these transformations are uniquely homogeneously catalyzed. Although mechanistic pathways associated with the carbonylation of methanol to acetic acid are well‐established, uncertainty surrounds the mechanism of the initial step in the reduction of CO, to a purported formyl intermediate, during its direct conversion to oxygenates. A characteristic mechanistic feature of the latter chemistry is the operation of kinetic reaction control that is manifest in the absence of the thermodynamically favored products, hydrocarbons (particularly methane); with the exception of catalysts for methanol manufacture, this behavior is in sharp contrast to that of typical heterogeneous catalysts for synthesis gas reactions.
Oxygenates Synthesis—Homogeneous
Authors: Whyman Robin 
Published: February 2011

AbstractThe current status of direct (from CO/H2) and indirect (via methanol, formaldehyde, dimethyl ether, or methyl acetate) homogeneously catalyzed C1chemistry based routes for the selective production of methanol, ethanol, and ethylene glycol (including higher alcohols, diols, and acetate esters), acetic acid, propionic acid and methyl propionate, ethyl and vinyl acetate, acetic anhydride, and methyl formate is described. Whereas none of the direct routes have been commercialized, largely because of low catalytic activities and extreme operating pressure requirements, indirect routes including the Co‐, Rh‐, and Ir‐catalyzed carbonylation of methanol to acetic acid, Rh‐catalyzed carbonylation of methyl acetate to acetic anhydride (and coproduction of both), and Pd‐catalyzed methoxycarbonylation of ethylene to methyl propionate comprise established commercial processes. The majority of these transformations are uniquely homogeneously catalyzed.Although mechanistic pathways associated with the carbonylation of methanol to acetic acid are well established, uncertainty still surrounds the mechanism of the initial step in the reduction of CO, to a putative formyl intermediate, during its direct conversion to oxygenates. A characteristic mechanistic feature of the latter chemistry is the operation of kinetic reaction control that is manifest in the absence of the thermodynamically favored products, hydrocarbons (particularly methane); with the exception of catalysts for methanol manufacture, this behavior is in sharp contrast to that of typical heterogeneous catalysts for synthesis gas reactions.
Aldol Reaction—Homogeneous
Authors: Xu Li‐Wen , Li Li , Cai Yong‐Feng 
Published: February 2011

AbstractThe aldol reaction is one of the oldest and important methods for the construction of carbon–carbon bonds in organic chemistry. Over the last 30 years, tremendous efforts have resulted in the development of many highly sophisticated and efficient catalytic methods of modern aldol reactions in catalytic chemo‐, regio‐, enantio‐, and diastereoselective manners. This review outlined those efforts in homogeneous catalysis and discussed with selected examples (331 publications) according to the different elemental types of catalysts, for example, transition metals and rare earth metals based Lewis acids, main group metals based catalysts, multifunctional catalysts, and metal‐free catalysts.
Self‐Sharpening Teeth: Self‐Sharpening Mechanism of the Sea Urchin Tooth (Adv. Funct. Mater. 4/2011)
Authors: Killian Christopher E. , Metzler Rebecca A. , Gong Yutao , Churchill Tyler H. , Olson Ian C. , Trubetskoy Vasily , Christensen Matthew B. , Fournelle John H. , De Carlo Francesco , Cohen Sidney , Mahamid Julia , Scholl Andreas , Young Anthony , Doran Andrew , Wilt Fred H. , Coppersmith Susan N. , Gilbert Pupa U. P. A. 
Published: February 2011

AbstractThe sea urchin tooth is a mosaic of calcite crystals shaped precisely into plates and fibers, cemented together by a robust calcitic polycrystalline matrix. The tooth is formed continuously at one end, while it grinds and wears at the opposite end, the sharp tip. Remarkably, these teeth enable the sea urchin to scrape and bore holes into rock, yet the teeth remain sharp rather than dull with use. Here we describe the detailed structure of the tooth of the California purple sea urchin Strongylocentrotus purpuratus, and focus on the self‐sharpening mechanism. Using high‐resolution X‐ray photoelectron emission spectromicroscopy (X‐PEEM), scanning electron microscopy (SEM), EDX analysis, nanoindentation, and X‐ray micro‐tomography, we deduce that the sea urchin tooth self‐sharpens by fracturing at discontinuities in the material. These are organic layers surrounding plates and fibers that behave as the “fault lines” in the tooth structure, as shown by nanoindentation. Shedding of tooth components at these discontinuities exposes the robust central part of the tooth, aptly termed “the stone”, which becomes the grinding tip. The precise design and position of the plates and fibers determines the profile of the tooth tip, so as the tooth wears it maintains a tip that is continually renewed and remains sharp. This strategy may be used for the top‐down or bottom‐up fabrication of lamellar materials, to be used for mechanical functions at the nano‐ and micrometer scale.
Domino CN Coupling/Annulation versus CN Coupling/ Hydroamination of 2‐Alkynyl‐3‐bromobenzothiophenes and 2‐Alkynyl‐3‐bromothiophenes. Highly Efficient Synthesis of Benzothieno[3,2‐b]quinolines and Thieno[3,2‐b]pyrroles
Authors: Salman Ghazwan Ali , Hussain Munawar , Iaroshenko Viktor , Villinger Alexander , Langer Peter 
Published: February 2011

AbstractWhile the palladium‐catalyzed reaction of 2‐alkynyl‐3‐bromothiophenes with anilines afforded thienopyrroles by a domino CN coupling/hydroamination process, the reaction of 2‐alkynyl‐3‐bromobenzothiophenes with anilines resulted, under identical conditions, in the formation of benzothienoquinolines by a domino CN coupling/annulation process. The electronic character of the aniline also has an influence on the product distribution.
Stable and Efficient Solid‐State Light‐Emitting Electrochemical Cells Based on a Series of Hydrophobic Iridium Complexes
Authors: Costa Rubén D. , Ortí Enrique , Tordera Daniel , Pertegás Antonio , Bolink Henk J. , Graber Stefan , Housecroft Catherine E. , Sachno Ludmila , Neuburger Markus , Constable Edwin C. 
Published: February 2011

AbstractLight‐emitting electrochemical cells (LECs) based on ionic transition‐metal complexes (iTMCs) exhibiting high efficiency, short turn‐on time, and long stability have recently been presented. Furthermore, LECs emitting in the full range of the visible spectrum including white light have been reported. However, all these achievements were obtained individually, not simultaneously, using in each case a different iTMC. In this work, device stability is maintained by employing intrinsically stable ionic iridium complexes, while increasing the complex and the device quantum yields for exciton‐to‐photon conversion. This is done by sequentially modifying the archetype ionic iridium complex [Ir(ppy)2(bpy)][PF6], where Hppy is 2‐phenylpyridine and bpy is 2,2'‐bipyridine, with methyl and phenyl groups on the bpy ligand. A full photophysical and theoretical description of a series of four complexes, including the archetype as a reference, is presented and their performance in LECs is characterized. Upon selecting suitable substituents, a twofold increase is obtained in the photoluminescence quantum yield in a solid film. This is reflected in a significant increase in the efficiency over time curve for LECs using this complex.
Synthesis of cross‐linked polyethylene oxide‐acetal macrocycles for solid superbase catalysts
Authors: Trofimov Boris A. , Morozova Boris V. , Mikhaleva Al'bina I. , Tatarinova Inna V. , Markova Marina V. , Henkelmann Jochem 
Published: February 2011

AbstractA novel long‐chain divinyl ether of tris(diethyleneglycol)‐bisacetal, has been synthesized by electrophilic addition of one molecule of diethylene glycol to two molecules of divinyl ether of diethylene glycol (DVDEG) in the presence of CF3COOH in quantitative yield. The monomer was cationically polymerized (BF3·OEt2, or complex LiBF4·MeO(CH2)2OMe) and copolymerized with DVDEG to deliver solid polymers the yields being 80–100%. The polymers represent the cross‐linked polyether‐polyacetal structures comprising macrocycles. The polymers were treated with 3% solution of KOH or CsOH in methanol to afford solid superbase complexes of KOH (CsOH) with cross‐linked polyether‐polyacetal macrocyclic networks. Preliminary tests have shown the complexes to be active catalysts for ethynylation of acetones and prototropic isomerization of methyl propargyl ethers to allenyl methyl ethers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Moisture‐induced effects on the tensile mechanical properties and glass‐transition temperature of poly(vinyl alcohol) films
Authors: Konidari M. V. , Papadokostaki K. G. , Sanopoulou M. 
Published: February 2011

AbstractIn this study, the effect of sorbed water on the tensile mechanical properties of noncrosslinked, thermally treated poly(vinyl alcohol) (PVA) films was studied. The Young's modulus, elongation at break, and tensile strength of the PVA films equilibrated at different relative humidities (0–86%) are reported, together with the depression of the glass transition of the polymer at each equilibrating humidity, as determined by temperature‐modulated differential scanning calorimetry. The results indicate that drastic changes in the tensile properties were correlated with the transition of the hydrated polymer from the glassy to the rubbery state. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of a nanoclay/triphenyl phosphate hybrid system on the fire retardancy of polycarbonate/acrylonitrile–butadiene–styrene blend
Authors: Feyz E. , Jahani Y. , Esfandeh M. 
Published: February 2011

AbstractThe effect of a hybrid system of nanoclay and triphenyl phosphate (TPP) on the fire retardancy of a polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) blend was examined in this study. The nanoclay in the polymers decreased the peak heat release rates (PHRRs) with no significant effect on the ease of ignition and times to extinguishment. Improvements in the flame retardancy were observed only when nanoparticles were used with conventional flame‐retardant (FR) additives. Thermogravimetric analysis (TGA), cone calorimetry, and limited oxygen index (LOI)/UL 94 (Underwriters Laboratory) testing were used to investigate the thermal degradation, fire behavior, and flammability of the materials. The results show that when we used a combination of TPP and nanoclay as an FR system, degradation of the polymer blends was reduced as the TGA curves shifted to higher temperatures. PHRR in cone calorimetry testing decreased from 1032 kW/m2 for the PC/ABS blend to 300 kW/m2 for the PC/ABS/(12% TPP–2% nanoclay) sample, and the LOI increased from 23 to 35%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of glutaraldehyde‐crosslinked calcium alginate for fluoride removal from aqueous solutions
Authors: Vijaya Y. , Popuri Srinivasa R. , Reddy A. Subba , Krishnaiah A. 
Published: February 2011

AbstractA novel biosorbent was developed by the crosslinking of an anionic biopolymer, calcium alginate, with glutaraldehyde. The glutaraldehyde‐crosslinked calcium alginate (GCA) was characterized by Fourier transform infrared spectroscopy and porosity and surface area analysis. The batch equilibrium and column flow adsorption characteristics of fluoride onto the biosorbent were studied. The effects of the pH, agitation time, concentration of adsorbate, and amount of adsorbent on the extent of adsorption were investigated. The experimental data were fitted to the Langmuir and Freundlich adsorption isotherms. The data were analyzed on the basis of the Lagergren pseudo‐first‐order, pseudo‐second‐order, and Weber–Morris intraparticle diffusion models. The maximum monolayer adsorption capacity of the GCA sorbent as obtained from the Langmuir adsorption isotherm was found to be 73.5 mg/g for fluoride. The χ2 and sum of squares of the error analysis were used to correlate the equilibrium isotherm models and kinetics. In addition, breakthrough curves were obtained from column flow experiments. The experimental results demonstrate that the GCA beads could be used for the defluoridation of drinking water through adsorption. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Nanocomposite super‐swelling hydrogels with nanorod bentonite
Authors: Darvishi Z. , Kabiri K. , Zohuriaan‐Mehr M. J. , Morsali A. 
Published: February 2011

AbstractA modified bentonite (nanorod bentonite) was obtained from conventional bentonite by an ultrasonic treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that modified bentonite comprised rod‐shape morphology without any change in the chemical structure confirmed by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) patterns. Novel super‐swelling hydrogels with nanocomposite structure were then prepared via solution polymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and (N‐[3‐(dimethylamino)propyl] methacrylamide) (DMAPMA) in the presence of the nanobentonite and a crosslinker. The DMAPMA consisted of either intercalant or monomer in the polymerization. The hydrogel products were characterized by FTIR, swelling studies, dynamic mechanical thermal analysis (DMTA), XRD, and rheological measurements. It was proposed that exfoliated and intercalated morphology were obtained at low and high‐nanobentonite contents, respectively. DMTA indicated that mechanical properties of the dried gel were improved with raising the clay content. In the water‐swollen state, storage modulus was considerably increased in nanocomposites having <8% of modified bentonite, and then it was decreased at the higher clay content due to interfering effect of the clay in polymerization progression. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology, crystallization, and mechanical properties of poly(ethylene terephthalate)/multiwalled carbon nanotubes composites
Authors: Zhu Zhiguo , Wang Rui , Dong Zhenfeng , Huang Xiuqin , Zhang Dasheng 
Published: February 2011

AbstractPoly(ethylene terephthalate)/multiwalled carbon nanotubes (PET/MWCNTs) with different MWCNTs loadings have been prepared by in situ polymerization of ethylene glycol (EG) containing dispersed MWCNTs and terephthalic acid (TPA). From scanning electronic microscopy images of nanocomposites, it can be clearly seen that the PET/MWCNTs composites with low‐MWCNTs contents (0.2 and 0.4 wt %) get better MWCNTs dispersion than analogous with high‐tube loadings (0.6 and 0.8 wt %). The nonisothermal crystallization kinetics was analyzed by differential scanning calorimetry using Mo kinetics equation, and the results showed that the incorporation of MWCNTs accelerates the crystallization process obviously. Mechanical testing shows that, in comparison with neat PET, the Young's modulus and the yield strength of the PET nanocomposites with incorporating 0.4 wt % MWCNTs are effectively improved by about 25% and 15%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Retracted: Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels
Authors: Alarifi Abdullah S. 
Published: February 2011

AbstractThe following article from the Journal of Applied Polymer Science, “Drug release properties of poly(vinyl pyrrolidone)/acrylic acid copolymer hydrogels,” by Abdullah S. Alarifi, published online on 14 February 2011 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 120, pp. 3484‐3489, has been retracted by agreement between the journal's editors and Wiley Periodicals, Inc. The retraction has been agreed because of unacknowledged overlap with work previously published in the Arab Journal of Nuclear Sciences and Applications (2010, 43, 366), as well as in Proceeding, 2nd International Conference on Radiation Sciences and Applications (Egyptian Society of Radiation Sciences and Applications: Marsa Alam, Egypt, 2010; p 362).
Understanding the degradation of MEA in PEMFC: Definition of structural markers and comparison between laboratory and on‐site ageing
Authors: De Moor Gilles , Bas Corine , Lesage Freddy , Danérol Anne Sophie , Claude Eric , Rossinot Elisabeth , Paris Marion , Flandin Lionel , Albérola Nicole Dominique 
Published: February 2011

AbstractDifferent accelerated tests in 12 fuel cells stack were performed in laboratory, namely on/off, back‐up, and base‐load regimes. In parallel, membrane electrode assemblies (MEA) were integrated in two “on‐site” systems for GSM relay application. One of them was dedicated to base‐load power applications while the second fuel cells coupled with photovoltaic panels operated in semibase load mode. To investigate the influence of the power profiles on MEA degradation, over 80 CCB MEAs (5 layers) were studied at different scales using ex situ characterizations such as tensile tests, TGA‐MS, DMTA, and SEM. A series of complementary microstructural ageing markers were thereby identified. The isolated influence of dry‐wet cycling on MEA properties was also established after passive hydro‐thermal (HT) ageing performed continuously for 10 months in the laboratory. The changes of each marker as a function of HT ageing time permitted to define a temporal benchmark. Based on these indicators, the main changes occurred in the MEA properties appear after a 5 months dry‐humid cycling (up to about 1800 cycles). The trends observed were useful to compare and estimate the degree of degradation of each ageing tests. Thus, the accelerated tests performed in laboratory for at least 500 h in stack did not reveal systematic MEA modifications. On the contrary, the 1500 h “on‐site” system operation results in some MEA degradations which origins are discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of pro‐oxidants on biodegradation of polyethylene (LDPE) by indigenous fungal isolate, Aspergillus oryzae
Authors: Konduri Mohan K. R. , Koteswarareddy G. , Rohini Kumar D. B. , Venkata Reddy B. , Lakshmi Narasu M. 
Published: February 2011

AbstractProxidant additives represent a promising solution to the problem of the environment contamination with polyethylene film litter. Pro‐oxidants accelerate photo‐ and thermo‐oxidation and consequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. In the present study, fungal strain, Aspergillus oryzae isolated from HDPE film (buried in soil for 3 months) utilized abiotically treated polyethylene (LDPE) as a sole carbon source and degraded it. Treatment with pro‐oxidant, manganese stearate followed by UV irradiation and incubation with A. oryzae resulted in maximum decrease in percentage of elongation and tensile strength by 62 and 51%, respectively, compared with other pro‐oxidant treated LDPE films which showed 45% (titanium stearate), 40% (iron stearate), and 39% (cobalt stearate) decrease in tensile strength. Fourier transform infrared (FTIR) analysis of proxidant treated LDPE films revealed generation of more number of carbonyl and carboxylic groups (1630–1840 cm−1 and 1220–1340 cm−1) compared with UV treated film. When these films were incubated with A. oryzae for 3 months complete degradation of carbonyl and carboxylic groups was achieved. Scanning electron microscopy of untreated and treated LDPE films also revealed that polymer has undergone degradation after abiotic and biotic treatments. This concludes proxidant treatment before UV irradiation accelerated photo‐oxidation of LDPE, caused functional groups to be generated in the polyethylene film and this resulted in biodegradation due to the consumption of carbonyl and carboxylic groups by A. oryzae which was evident by reduction in carbonyl peaks. Among the pro‐oxidants, manganese stearate treatment caused maximum degradation of polyethylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Solution casting, characterization, and performance evaluation of perfluorosulfonic sodium type membranes for chlor‐alkali application
Authors: Mohammadi Fereidoon , Rabiee Ahmad 
Published: February 2011

AbstractThis investigation describes solution casting, characterization and performance evaluation of perfluorosulfonic sodium (PFSS) type membranes prepared by three different methods from Nafion solution and Nafion‐117 for Chlor‐Alkali (CA) application. A Chlor‐Alkali experimental set‐up was designed and constructed for performance evaluation of the recast membranes. The chemical structure of solution cast films was studied and confirmed by FTIR (Fourier Transform infrared spectroscopy) and ATR (Attenuated total reflection) techniques. The physical properties of solution cast films including mechanical strength, thermal behavior, water sorption, ion‐exchange capacity (IEC), morphology, and crystallinity were also evaluated. All the recast polymeric films behave like elastomers with low modulus but high elongation at break. Differential scanning calorimetric (DSC) thermograms of solution cast films showed two endothermic peaks at 180°C and 250°C attributed to matrix glass transition (Tgm) and ionic cluster glass transition (Tgc) of the Nafion polymer, respectively. The water uptake of polymeric films was reasonable in comparison with Nafion‐117. Solution casting has no significant effect on ion exchange capacity of the recast films. The scanning electron microscope (SEM) micrograph showed that the morphology of recast films is reasonably similar with Nafion‐117. However, the as‐cast films have some micro pores, which are produced during solution casting. The crystallinity of annealed film, because of the heat treatment was slightly high due to local ordering. According to the experimental results, which obtained from performance evaluation in CA cell, the properties of recycled films are similar to commercial membranes such as Nafion‐117 and can be used in CA process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011