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Chlorosulfonic Acid (chlorosulfonic + acid)
Selected AbstractsEnhanced Electrical Switching and Electrochromic Properties of Poly(p-phenylenebenzobisthiazole) Thin Films Embedded with Nano-WO3ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Jiahua Zhu Abstract The electrical switching and electrochromic phenomena of a novel nanocomposite comprising poly(p-phenylenebenzobisthiazole) (PBZT) and tungsten oxide (WO3) nanoparticles are investigated as a function of the nanoparticle loading. Both dissolving PBZT and doping PBZT backbone structure with acid are achieved by one simple step. Chlorosulfonic acid (CSA) is used as a solvent and spontaneously transformed to sulfuric acid upon exposure to moisture. The formed sulfuric acid serves as doping agent to improve the electrical conductivity of PBZT. The most significant enhancement of electrical switching is observed in the nanocomposites with low weight fraction (5%). The electrical conductivity of 5% WO3/PBZT nanocomposite thin film is increased by about 200 times and 2 times, respectively, as compared to those of the as-received PBZT and PBZT/CSA thin films. As the nanoparticle loading increases to 20% and 30%, the nanocomposites follow an ohmic conduction mechanism. Stable electrical conductivity switching is observed before and after applying a bias on the pristine PBZT and WO3/PBZT nanocomposite thin films. Electrochromic phenomena of both PBZT and WO3/PBZT nanocomposite thin films with high contrast ratio are observed after applying a bias (3 V). The mechanisms of the nanoparticles in enhancing the electrical switching and electrochromic properties are proposed. [source] Selective Synthesis of 1,4-Dialkylbenzenes from Terephthalic AcidADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Andrea Bramborg Abstract Terephthalic acid reacts with alkyl halides under Birch conditions to substituted 1,4-cyclohexadienes in high yields and good stereoselectivities. Electrophiles containing ester or nitrile groups undergo a surprising fragmentation under the reaction conditions. Subsequent treatment with chlorosulfonic acid proceeds by an interesting tandem decarbonylation/decarboxylation, affording 1,4-dialkylbenzenes in excellent regioselectivity. Thus our new method is superior to classical Friedel,Crafts alkylations. [source] Polymer electrolyte membranes having sulfoalkyl grafts into ETFE film prepared by radiation-induced copolymerization of methyl acrylate and methyl methacrylateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009Truong Thi Hanh Abstract Polymer electrolyte membranes (PEMs) containing alkylsulfonic acid grafts can be prepared by radiation-induced graft copolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) into a poly(ethylene- co -tetrafluoroethylene) film followed by sulfonation of the MA units in the copolymer grafts using an equimolar complex of chlorosulfonic acid and 1,4-dioxane (ClSO3H-Complex). PEMs with MA/MMA copolymer grafts that are 33%,79% MA units were prepared by preirradiation with a dose of 20 kGy and grafting in bulk comonomers at 60°C. The grafted films are treated with ClSO3H-Complex to obtain PEMs with ion exchange capacity of 0.36-0.81 mmol/g (sulfonation degrees of 20%,40%) and proton conductivity of 0.04-0.065 S/cm. These values can be controlled by changing the MA content the sulfonation occurring at an ,-carbonyl carbon. The PEMs with higher MMA content showed higher durability in water (80°C) and under oxidative conditions (3% H2O2) at 60°C. This is because the PMMA grafts in the PEMs have no proton at an ,-carbonyl carbon, which is considered to be a trigger of the degradation of grafting polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Preparation of sheath,core bicomponent composite ion-exchange fibers and their propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Zhi-Jia Ding Abstract Based on sheath,core bicomponent composite ion-exchange fibers with modified polystyrene and modified polypropylene, composite fibers were further crosslinked and sulfonated with chlorosulfonic acid to produce strongly acidic cation-exchange fibers. The optimal technology of the obtained fibers was examined, and the structures of the fibers were investigated with Fourier transform infrared spectrophotometry, differential scanning calorimetry, and so forth. The properties were measured with chemical titration, filament strength instrumentation, scanning electron microscopy, and so forth. The results showed that cation-exchange fibers with better mechanical properties and a higher exchange capacity were obtained, and they had higher practicability. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Sulfonated poly(ether imide) and poly(ether sulfone) blends for direct methanol fuel cells.JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Abstract This investigation examines characteristics of sulfonated polyether imides (SPEI) with various ion exchange capacity values (IEC) and completes previous work to enable its blends to be adopted as polyelectrolyte in direct methanol fuel cells (DMFC). Polyether imides (PEI) were sulfonated by using chlorosulfonic acid as the sulfonating agent and chloroform as the solvent. The structure of SPEI was observed by FTIR and 1H NMR. The sulfonate or sulfonic acid content of the polymers, expressed as a number per repeat unit of the polymer, was accurately determined by elemental analysis and conductometric titration. Physical properties such as solubility, intrinsic viscosities, thermal stability, and glass transition temperature (Tg) were studied for both PEI and SPEI. TGA-FTIR verified that sulfonic groups, attached to the aromatic ring in the PEI backbone, are split at 230,350°C, but the main-chain splitting temperature of SPEI is similar to that of pure polymer. The sulfonated samples exhibited good solubilities and increased glass transition temperatures (Tg values) as degree of sulfonation (DS) increased; two Tg values were detected when IEC was sufficiently high. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Synthesis, properties, and sulfonation of novel dendritic multiblock copoly(ether-sulfone)JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2008Sumiko Matsumura Abstract Multiblock copoly(ether-sulfone)s (PESs) bearing anchor units for the construction of dendritic blocks were synthesized by two-step reactions: (1) synthesis of PES block with both phenoxide end-groups; (2) chain extension and end-capping of the block by use of excess novel hexafunctional agent, hexakis(4-(4-fluorophenylsulfonyl)phenyl)benzene. The optimum average block length (n) and amount (x) of the hexafunctional agent used for the synthesis of high-molecular-weight PES without crosslinking were n = 26 and x = 2.6 equiv, respectively. The dendritic blocks in the PES were constructed by the aromatic nucleophilic substitution reaction of the activated aromatic fluoride groups on the anchor units using 4-tritylbenzenethiol. The clean substitution of the fluoride groups in the PES was confirmed by 1H NMR and 19F NMR. Three sulfonic acid groups were introduced on the pendant phenyl rings of the trityl groups in the PES by the reaction with chlorosulfonic acid. This is the first example of a dendritic PES bearing clusters of sulfonic acid groups only on the dendritic blocks. Cast films of presulfonated dendritic PES were strong and flexible, however, the membranes of sulfonated dendritic PES were brittle so that the conductivity measurements were not performed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6365,6375, 2008 [source] Effect of sulfonic group on solubility parameters and solubility behavior of poly(2,6-dimethyl-1,4-phenylene oxide)POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2007Chunli Gong Abstract An investigation on the effect of sulfonic group on solubility parameters and solubility behavior of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) is presented. Sulfonated PPO (SPPO) was prepared using chlorosulfonic acid as a sulfonating agent. The structure of SPPO was confirmed by FT-IR, and the ion exchange capacity (IEC) of SPPO was accurately determined by conductometric titration and 1H-NMR. The three-dimensional solubility parameters of SPPO defined by Hansen were estimated by group contribution, and this approach was used to obtain the three coordinates of a solubility parameter in terms of: a dispersion part ,d, a polar part ,p and a hydrogen bonding part ,h. The theoretical predications of solubility behavior were characterized using "soluble sphere" in three-dimensional space. The estimated results were in accordance with the solubility experiments in different solvents. Copyright © 2006 John Wiley & Sons, Ltd. [source] Sulfonated poly(phenylene oxide) membranes as promising materials for new proton exchange membranesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 5 2006Shifang Yang Abstract Poly(phenylene oxide) (PPO) was sulfonated to different ion exchange capacities (IECs) using chlorosulfonic acid as the sulfonating agent. Tough, ductile films were successfully cast from sulfonated PPO (SPPO) solutions in N -methyl-2-pyrrolidone or N,N -dimethylformamide. The obtained membranes had good thermal stability revealed by thermogravimetric analysis (TGA). Compared with an unsulfonated PPO membrane, the hydrophilicity and water uptake of the SPPO membranes were enhanced, as shown by reduced contact angles with water. The tensile test indicated that the SPPO membranes with IEC ranging from 0.77 to 2.63,meq/g were tough and strong at ambient conditions and still maintained adequate mechanical strength after immersion in water at room temperature for 24,hr. The results of wide-angle X-ray diffraction (WAXD) showed amorphous structures for PPO and SPPO while the peak intensity decreased after sulfonation. The proton conductivity of these SPPO membranes was measured as 1.16,×,10,2,S/cm at ambient temperature, which is comparable to that of Nafion 112 at similar conditions and in the range needed for high-performance fuel cell proton exchange membranes. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||