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Toluenesulfonic Acid (toluenesulfonic + acid)
Selected AbstractsChemInform Abstract: One-Pot Synthesis of Diaryliodonium Salts Using Toluenesulfonic Acid: A Fast Entry to Electron-Rich Diaryliodonium Tosylates and Triflates.CHEMINFORM, Issue 29 2008Mingzhao Zhu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] One-Pot Synthesis of Core-Modified Rubyrin, Octaphyrin, and Dodecaphyrin: Characterization and Nonlinear Optical PropertiesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2007Rajeev Kumar Abstract Modified 26, rubyrin, 36, octaphyrin, and 54, dodecaphyrin systems have been synthesized in moderately good yields through acid-catalyzed condensations of terthiophene diols and tripyrranes. The product distributions are decided both by the acid catalyst concentration and by the nature of the meso substituents. For example, a new isomer of [26]hexaphyrin(1.1.1.1.0.0) (rubyrin) was obtained with 0.3 equiv. of p -toluenesulfonic acid, when the meso substituent was mesityl in at least one of the precursors. A change of the mesityl substituent for a p -methoxy substituent in terthiophene diol resulted in the formation of a [3,+,3,+,3,+,3] condensation product , [54]dodecaphyrin(1.1.1.1.0.0.1.1.1.1.0.0) , in addition to the expected rubyrin. Furthermore, an increase in the acid concentration to 0.6 equiv. resulted in the formation of a new [36]octaphyrin(1.1.1.1.1.1.0.0), in addition to the rubyrin and dodecaphyrin. A single-crystal X-ray analysis of octaphyrin represents the first example of a planar conformation of an octaphyrin with six meso links. In rubyrin 19, one thiophene ring, opposite to the terthiophene subunit, is inverted, while in octaphyrin 30 one pyrrole ring and two thiophene rings are inverted. The various conformational possibilities tested for the unsubstituted dodecaphyrin 28, at semiempirical level, suggest that the most stable conformation is a figure-eight. The final geometry optimization of figure-eight dodecaphyrin was done at the B3LYP/6-31G* level of DFT. Octaphyrins and dodecaphyrins bind trifluoroacetate anion effectively in their diprotonated forms, the binding constants (K) being 638 M,1 for dodecaphyrin 28, and 415 M,1 for octaphyrin 30. Electrochemical data reveal HOMO destabilization with increasing , electron conjugation, consistently with the large red shifts of the absorption bands. Preliminary studies on the use of these expanded porphyrins as third-order NLO materials were followed by measurements of their two-photon absorption (TPA) cross-sections [,(2)]. The ,(2) values increase upon going from the 26, rubyrins to the 54, dodecaphyrins, confirming our earlier observation that increases in ,-conjugated electrons increase the TPA values.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Correlation analysis of reactivity in the oxidation of anilines by nicotinium dichromate in nonaqueous mediaINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2006D. S. Bhuvaneshwari The kinetics of oxidation of 15 para- and meta-substituted anilines by nicotinium dichromate (NDC) in different organic solvent media in the presence of p -toluenesulfonic acid (TsOH) has been investigated. The rate of the reaction is zero order with respect to substrate, first order in NDC, and is found to increase with increase in [TsOH]. The various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of the isokinetic relationship. The specific rate of oxidizing species-anilines reaction (k2) correlates with Hammett's substituent constants affording negative reaction constants. The effect of para- and meta-substituents on the oxidation rates confirms to Swain et al.'s substituent constants F and R, both with negative reaction constants. The rate data failed to correlate with macroscopic solvent parameters such as ,r and E while showing satisfactory correlation with Kamlet,Taft's solvatochromic parameters (,, ,, and ,*). © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 657,665, 2006 [source] Studies on the kinetics of imidazolium fluorochromate oxidation of some meta - and para -substituted anilines in nonaqueous mediaINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2006D. S. Bhuvaneshwari The imidazolium fluorochromate (IFC) oxidation of meta - and para -substituted anilines, in seven organic solvents, in the presence of p -toluenesulfonic acid (TsOH) is first order in IFC and TsOH and is zero order with respect to substrate. The IFC oxidation of 15 meta - and para -substituted anilines at 299,322 K complies with the isokinetic relationship but not to any of the linear free energy relationships; the isokinetic temperature lies within the experimental range. The specific rate of oxidizing species-anilines reaction (k2) correlates with substituent constants affording negative reaction constants. The rate data failed to correlate with macroscopic solvent parameters such as ,r and ENT. A correlation of rate data with Kamlet,Taft solvatochromic parameters (,, ,, ,*) suggests that the specific solute,solvent interactions play a major role in governing the reactivity, and the observed solvent effects have been explained on the basis of solute,solvent complexation. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 166,175, 2006 [source] Eco-friendly methodologies for the synthesis of some aromatic esters, well-known cosmetic ingredientsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005C. Villa Synopsis Solid,liquid solvent-free phase transfer catalysis (PTC) and acidic catalysis in dry media were applied, with noticeable improvement and simplification over classical procedures in a Green Chemistry context, to the synthesis of some aromatic esters useful as cosmetic ingredients: 3-methylbutyl 4-methoxycinnamate, 2-ethylhexyl 4-methoxycinnamate, 2-ethylhexyl 4-(dimethylamino)benzoate and 2-ethylhexyl salicylate, well-known ultraviolet B sunscreen filters; 4-isopropylbenzyl salicylate, UV absorber and cutaneous antilipoperoxidant; propyl 4-hydroxybenzoate and butyl 4-hydroxybenzoate (parabens), antimicrobial agents. The reactions were performed under microwave (MW) activation and conventional heating. The best results for the synthesis of cinnamic, salicylic and 4-(dimethylamino)benzoic esters were achieved by in situ preformed carboxylates alkylation with alkyl bromides using PTC. The 4-hydroxybenzoates were obtained in good yields by classical esterification of the acid with alcohols using a simple heterogeneous mixture of reagents with catalytic amounts of p -toluenesulfonic acid (PTSA). The comparisons of yields and thermal profiles under either MW or conventional heating were studied and reported. Résumé La catalyse par transfert de phase (CTP) solide-liquide sans solvant et l'estérification acido-catalysée en ,,milieu sec'' ont été appliquées, dans le cadre de la ,,chimie verte'', avec des nettes améliorations et simplifications par rapport aux méthodes classiques, à la synthèse de certains esters aromatiques, ingrédients cosmétiques: 3-methylbutyl 4-méthoxycinnamate, 2-éthylhéxyl 4-méthoxycinnamate, 2-éthylhéxyl 4-(diméthylamino) benzoate et 2-éthylhéxyl salicylate, filtres solaires UVB bien connus; 4-isopropylbenzyl salicylate, filtre UV et antilipopéroxydant cutané; propyl 4-hydroxybenzoate et butyl 4-hydroxybenzoate (parabens), agents antimicrobien. Les réactions ont été procédées sous irradiation micro-onde et par chauffage classique. Pour la synthèse des esters dérivés de l'acide cinnamique, salicylique et 4-(diméthylamino)benzoïque les meilleurs résultats ont été obtenus grâce à la CTP par alkylation des carboxylates (préformés in situ) avec des bromures d'alkyle. Les esters de l'acide 4-hydroxybenzoique ont été obtenus avec de bons rendements par simple mélange hétérogène des réactifs et d'acide p-toluènesulfonique (PTSA) comme catalyseur. Les rendements et les profils de montée en température sous micro-ondes et par chauffage classique ont été comparés. [source] One-Pot Synthesis of Quinoline Derivatives Directly from Terminal Alkynes via Sequential Ruthenium(II) and Acid CatalysisADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Min Zhang Abstract A convenient one-pot synthesis of 2,3-disubstituted, 2,3,6-trisubstituted, and 2,3,6,7-tetrasubstituted quinoline analogues from terminal alkynes via sequential ruthenium(II) and para -toluenesulfonic acid (p -TSA) co-catalyzed reactions is described. The catalytic process is shown to take place first via intermediate formation of an allyl ketone and then addition of an aniline derivative to the allyl ketone. The p -TSA is a catalyst for both allyl ketone and quinoline synthetic steps. The method allowed us to synthesize a wide range of quinoline derivatives and introduce different substituents by employing various simple starting materials. The reaction allows the synthesis of halogen-containing products. [source] Various ,-Oxygen Functionalizations of ,-Dicarbonyl Compounds Mediated by the Hypervalent Iodine(III) Reagent p -Iodotoluene Difluoride with Different Oxygen-Containing NucleophilesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Jun Yu Abstract p -Iodotoluene difluoride (p -Tol-IF2) has been found to be a general reagent for the effective introduction of various oxygen-containing functionalities including tosyloxy, mesyloxy, acetoxy, phosphoryloxy, methoxy, ethoxy and isopropoxy at the ,-position of ,-dicarbonyl compounds. These transformations can be readily realized by the use of the combined reagent of p -iodotoluene difluoride and various oxygen-containing nucleophilic compounds such as p -toluenesulfonic acid, methanesulfonic acid, acetic acid, diphenyl phosphate, methanol, ethanol and propan-2-ol under mild conditions, respectively. And, the in situ generated hypervalent iodine(III) species via ligand exchange between p -iodotoluene difluoride and the respective oxygen-containing nucleophiles are believed to be the real oxidizing agents in such transformations. [source] Synthesis and characterization of polypyrrole rod doped with p -toluenesulfonic acid via micelle formationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Duk Ki Kim Abstract Rod-type polypyrrole (PPY) doped with p -toluenesulfonic acid (TSA) was synthesized by chemical oxidative polymerization via a self-assembly process. The shape of the PPY particles is mainly determined by the ratio of TSA/pyrrole (PY) and feed rate of the oxidant. Particle of different shapes (rod, grain, and partially rod) exhibit differences in morphology, electrical properties, dispersity, and thermal properties. Wide-angle X-ray diffraction patterning analysis was used to investigate the mechanism of rod formation. The effect of the TSA concentration on the PPY structure was investigated using Fourier transform infrared spectroscopy. The PPY rods doped with TSA exhibited better electrical conductivity than granular PPY doped with TSA, and their dispersity and thermal stability were also higher. Self-orientation of PPY in the micelles of TSA and high crystallinity of the rod particles led to improved thermal stability. Hence, the decomposition temperature of the polymer chain was considerably increased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Facile one-step synthesis of electromagnetic functionalized polypyrrole/Fe3O4 nanotubes via a self-assembly processJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2010Wei-Dong Zhang Abstract This article reports a simple self-assembly process for facile one-step synthesis of novel electromagnetic functionalized polypyrrole (PPy)/Fe3O4 composite nanotubes using p -toluenesulfonic acid (p -TSA) as the dopant and FeCl3 as the oxidant. The key trick of the present method is to use FeCl3 as the oxidant for both PPy and Fe3O4 in the same time to synthesize PPy/Fe3O4 composite nanotubes in one-step. This facile one-step method is much simpler than the conventional approach using the Fe3O4 nanoparticles as the additives. Compared to the similar composites synthesized using the conventional method, the as-prepared PPy- p -TSA/Fe3O4 composite nanotubes using the facile one-step self-assembly process show much higher room-temperature conductivity. Moreover, the composite nanotubes display interesting ferromagnetic behavior. The electrical properties of the PPy- p -TSA/Fe3O4 composite nanotubes are dominated by the amount of FeCl3 while their magnetic properties are controlled by the amount of FeCl2. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 320,326, 2010 [source] Synthesis of Polypyrrole Using Benzoyl Peroxide as a Novel Oxidizing AgentMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 3 2006Chandrasekaran Saravanan Abstract Summary: Benzoyl peroxide is used as an oxidizing agent for the first time in the synthesis of conducting polypyrrole. Synthesis of polypyrrole is commonly performed by chemical oxidative polymerization using water-soluble oxidizing agents. In this work, polypyrrole was prepared using organic solvent-soluble benzoyl peroxide as an oxidizing agent in the presence of p -toluenesulfonic acid (p -TSA) and sodium lauryl sulfate (SLS) surfactant via the inverted-emulsion-polymerization technique. During polymerization, SLS is converted to dodecyl hydrogensulfate (DHS) and incorporated on to polypyrrole along with p -TSA dopant, indicating SLS is acting as emulsifier as well as dopant. The influence of synthesis conditions such as the duration of the reaction, the temperature, the concentration of the reactants, etc., on the properties of polypyrrole was investigated to determine the optimum conditions for the synthesis of polypyrrole salt. Polypyrrole was obtained in a reaction time of 1 h with high yield (154 wt.-% with respect to pyrrole used) and good conductivity (2 S,·,cm,1). The conductivity of polypyrrole-salt was found to be nearly the same even after seven months of storage at ambient temperature (1.7 S,·,cm,1). [source] Nanoscaled Polyaniline Fibers Prepared by Ferric Chloride as an OxidantMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2006Lijuan Zhang Abstract Summary: Nanoscaled polyaniline (PANI) fibers with 17,30 nm in diameter were successfully prepared by oxidation polymerization using ferric hydrochloride (FeCl3,·,6H2O) as an oxidant in the presence of p -toluenesulfonic acid (p -TSA), , -naphthalenesulfonic acid (, -NSA), and camphorsulfonic acid (CSA) as the dopants. The resulting nanofibers show smaller diameter, higher crystallinity and conductivity (10,1 S,·,cm,1) compared with the nanofibers oxidized by ammonium persulfate (APS), which may be due to the lower oxidation/reduction potential of FeCl3. SEM images of the PANI nanofibers prepared by oxidation polymerization using ferric hydrochloride as an oxidant. [source] Chemical and electrochemical synthesis of conducting graft copolymer of acrylonitrile with anilinePOLYMER INTERNATIONAL, Issue 9 2006S Hossein Hosseini Abstract A new conducting copolymer, polyacrylonitrile- graft -polyaniline (PAN- g -PANi), has been prepared by chemical and electrochemical methods from a precursor polymer. Poly[acrylonitrile- co -(acrylimine phenylenediamine)] (PAN- co -PAIPD) was synthesized chemically by reacting PAN with sodium 1,4-phenylenediamine salt. PAN- g -PANi was synthesized chemically using ammonium peroxydisulfate as the oxidant and p -toluenesulfonic acid in dimethylsulfoxide solution and adding aniline to oxidized PAN- co -PAIPD. Electrochemical polymerization was carried out by spin coating PAN- co -PAIPD on the surface of a Pt electrode, then the growth of the graft copolymer (PAN- g -PANi) in the presence of fresh aniline and acidic solution. The structures of the graft copolymer and PAN- co -PAIPD were characterized using UV-visible, Fourier transform infrared, and 1H and 13C NMR spectroscopies. The thermal properties of PAN- g -PANi were studied using thermogravimetric analysis and differential scanning calorimetry. Scanning electron microscopy (SEM) images showed that the morphology of PAN- g -PANi copolymer films was homogeneous. Electrical conductivity of the copolymer was studied using the four-probe method, which gave a conductivity of 4.5 × 10,3 S cm,1 with 51.4% PANi. SEM and electrical conductivity measurements supported the formation of the graft copolymer. Copyright © 2006 Society of Chemical Industry [source] | |||||||||||||