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Showing 1 to 20 of 58 for “"Protic"”.
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The dehydrochlorination of 1,1-diaryl-2,2,2-trichloroethanes in protic and dipolar aprotic solvents
… of the transition states of E2H reactions in protic solvents as well as the Winstein-Parker E2C-like transitions states for elimination by weak bases in dipolar aprotic solvents are described. PART II The use of primary deuterium isotope effects: structure-reactivity relationships, and …
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Part One: A Flow Reactor With In-Line Analytics: Design and Implementation Part Two: In-Line Derivatization of Protic Compounds for GC/MS Reaction Monitoring
The creation of an automated synthetic reaction system with in-line analytics is presented in two parts. First, the design and implementation of a flow reactor system complete with in-line gas chromatography mass spectrometry (GC/MS) analytical instrument is discussed. The testing and validation of …
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Aspects of the chemistry of 1,4-naphthoquinones. An investigation of nucleophilic substitution reactions of alkylamines and hydroxyalyklamines on 1,4 napthoquinones and the role of solvent on the position of substitution.
… regioisomers were produced in all the reactions, protic polar solvents favoured the formation of the 3-regioisomer, whereas non-protic solvents favoured the formation of the 2-regioisomer. It has also been found that formation of 2,3-diaminoalkyl derivatives is normally unlikely. A series of …
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Designing functional liquids
… the so far unknown reasons why Brønsted acidic protic ionic liquids (ILs) based on sulfuric acid exhibit favourable phase behaviour when compared to neat sulfuric acid in industrially relevant applications, such as catalysis or lignocellulosic biomass pre-treatment. <br/><br/> Following …
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Michael addition of amines to α-ß unsaturated esters
… was observed. The maximum rate was obtained in protic and polar solvents. The maximum temperature that equivalent amounts of primary amines and acrylates undergo the Michael addition without excessive formation of amide byproducts was about 50°C. The reaction rate was highly affected by the …
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Role of adsorption in catalysis: applications of NMR relaxometry
… was studied at 298 and 373 K. A series of polar protic, polar aprotic and non polar solvents was investigated. Results showed higher initial reaction rates in non polar solvents but higher selectivities towards desired products on polar protic solvents. Solvent used also affected by product …
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The Polymerisation of Sulphur containing Heterocycles
… been studied in some detail using both protic and aprotic bases. Kinetic studies have been carried out by means of gas evolution techniques and the reaction products (principally poly-a-thioesters) characterised. The characteristics of the reactions of the α-thioacidanhydrocarboxylates …
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Identities and Catalytic Functionalities of Reactive Hydrogen Species during Hydrogen Addition and Oxygen Removal Reactions of Carboxylic Acids, Carbonyls, and Phenols at Transition Metal-solvent Interfaces
At transition metal and protic solvent interfaces, H-adatoms (H*) derived from H2 (10-60 bar) dissociative adsorption, and protons (H+) derived from either H* ionization or solvent self-ionization are catalytically reactive H species. These H species participate in or assist with hydrodeoxygenation …
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Intermediates and Mechanisms of Gold(I)-Catalyzed Nucleophilic Addition Reactions
… gold(I)-catalyzed reactions may involve protic acids (H+), so it is significant to establish more detailed structure/activity relationships to determine the necessity of applying gold complexes. Previous literature at the outset of these studies focused on methodology explorations and …
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Measurement and Prediction of Limiting Activity Coefficients
… independent parameters. For about 3000 protic and aprotic, but nonaqueous and nonionic (gamma)('(INFIN))'s over wide temperature ranges, an average deviation of 11% was achieved with few unsatisfactory predictions. Overall, the temperature dependence of the (gamma)('(INFIN))'s was …
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Mechanistic and synthetic studies of the intramolecular [4+2] cycloaddition of conjugated enynes
… intermediates. An investigation of the use of protic solvents has shown that alcohols, in particular 2,2,2-trifluoroethanol, can significantly improve the isolated yield of products. The application of strained cyclic acetylenes, specifically arynes generated by a modification of the Kobayashi …
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Study of the reaction of nitriles with dialkyl phosphites for synthesis of a-Amino-bis-phosphonates
… synthesize these compounds involved the use of protic acids, which don’t provide ideal conditions for the starting materials containing acid labile functional groups in pharmaceutical compounds. The present study adopts a new synthetic route in which diethyl phosphite addition to the nitrile …
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The syntheses and reactions of thallium and dithallium dicarbollides
… by vacuum pyrolysis. The action of strong protic acids on Tl₂R¹R²C₂B₉H₉ produced the nido-carboranes, R¹R²C₂B₉H₉. The mechanism of the pyrolysis reaction and the proposed structures of the Tl₂R¹R²C₂B₉H₁₀ compounds are discussed. The compounds were identified by ¹H and ¹⁹B NMR, IR, mass …
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Estudio del comportamiento tribológico y de las interacciones de superficie de nuevos nanofluidos iónicos
… interactions and corrosion processes with protic and aprotic ionic liquids on copper and steel have been determined in order to develop new lubricants and lubricant additives. The tribological performance of new protic ammonium ionic liquids and aprotic imidazolium ionic liquids as …
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Computational Investigation of Spin Traps Using Hybrid Solvation Models.
… of the spin trap molecules properties in protic and aprotic polar solvents. The hybrid models have been successfully implemented to support the prominent role played by hydrogen bonding interactions in the stabilization of spin traps.</p>
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Reactions of quinones with aromatic ethers.
… have been cyclised in the presence of Lewis or protic acids to triphenylene-1,4-quinones. The reaction between concentrated hydrochloric acid and either 2,3-di(3',4'-dimethoxyphenyl)-benzoquinone or 5,6-dichloro-2,3-di(3',4'-dimethoxyphenyl)-benzoquinone gives 5-chloro-substituted …
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Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions
… Newman-Kwart rearrangement afforded desired mono-protic BINOL based sulfonic acid was successfully performed. This will be followed by evaluating sulfonic acid catalytic efficiencies towards asymmetric coupling reactions.</p> <p>The total synthesis of latifolian A through application of a chiral …
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Synthetic and structural studies of Calix[4]pyrogallolarenes: towards biological applications
… be formed by calix[4]pyrogallolarenes in polar protic solvents when the alkyl chain is substituted with bromine at its terminus. This is speculated to be due to formation of a dipolar interaction between the bromine atoms of adjacent calix[4]pyrogallolarene molecules. Calix[4]pyrogallolarenes …
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The synthesis and reactivity of some hydrocarbyl complexes of iron and ruthenium
… with donor ligands (CO, PMe₂Ph and PPh₃), protic acids (CF₃COOH and HCl), bromine, MeOH and with oxidants (Ph₃CPF₆ and AgBF₄) has been investigated. The new ruthenium complexes [{CpRu(CO)₂}₂{μ-(CnH₂n₋₁)}]PF₆ (n = 3 or 5), as well as their known iron analogues have been prepared. The crystal …
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Anionic synthesis and characterization of alkyl methacrylate containing polymeric systems
… of this class of polar monomers are the protic impurities present in most commercially available grades of monomer and the inherent side reactions associated with the ester functionality during anionic polymerization. However, by very carefully controlling various synthetic parameters and …
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