- Influence of Microwaves on the Rate of Esterification of 2,4,6-Trimethylbenzoic Acid with 2-Propanol
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The influence of microwave irradiation on the reaction kinetics of the acid-catalyzed esterification of 2,4,6-trimethylbenzoic acid in i-PrOH was investigated.The rate constants for the reaction at various temperatures were measured in experiments conduct
- Raner, Kevin D.,Strauss, Christopher R.
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- Scope and mechanistic insights into the use of tetradecyl(trihexyl) phosphonium bistriflimide: A remarkably selective ionic liquid solvent for substitution reactions
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A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimi nation side products. The structure-reactivity study indicates that these reactions proceed through a narrow spectrum of pathways ranging from straight SN2 to a preassociation pathway along a saddle point that approaches the SN1 limit. The barrier to the formation of dissociated carbocations is attributed to the structural features of this ionic liquid that favor intervention of the associated nucleophile over dissociation, also preventing cross over to E1 processes. The lack of any basic entity in the phosphonium bistriflimide ionic liquid appears to prevent any potential base-mediated elimination reactions, which makes this a highly selective medium for use in general substitution reactions.
- McNulty, James,Nair, Jerald J.,Cheekoori, Sreedhar,Larichev, Vladimir,Capretta, Alfredo,Robertson
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p. 9314 - 9322
(2007/10/03)
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- A mild esterification process in phosphonium salt ionic liquid
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A general, high yielding procedure is described for the esterification of carboxylic acids through carboxylate alkylation in phosphonium salt ionic liquid.
- McNulty, James,Cheekoori, Sreedhar,Nair, Jerald J.,Larichev, Vladimir,Capretta, Alfredo,Robertson, Al J.
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p. 3641 - 3644
(2007/10/03)
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- A New Microwave Reactor for Batchwise Organic Synthesis
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A laboratory-scale microwave batch reactor (MBR) has been developed for organic synthesis or kinetic studies on the 20-100 mL scale, with upper operating limits of 260 deg C and 10 MPa (100 atm).The MBR complements a continuous microwave reactor which was the subject of a previous report from the author's laboratory.Microwave-assisted organic reactions were conducted safely and conveniently in the MBR, for lengthy periods when required, and in volatile organic solvents.The use of water as a solvent for organic reactions was also explored.Examples include oxidation, elimination, esterifications, hydrolysis of a tertiary amide, etherification, isomerization, Hofmann elimination, α-iodination of a carboxylic acid, Claisen rearrangement, aminoreductone formation, and Willgerodt reactions.Advantages of the new MBR include the capability for rapid heating and quenching of reaction mixtures, minimal temperature gradients within the sample, and elimination of wall effects.Safety aspects have been discussed.
- Raner, Kevin D.,Strauss, Christopher R.,Trainor, Robert W.,Thorn, John S.
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p. 2456 - 2460
(2007/10/02)
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- Development and Application of a Continuous Microwave Reactor for Organic Synthesis
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A laboratory-scale continuous microwave reactor (CMR) has been developed and used to conduct organic syntheses routinely, rapidly, and safely in a range of solvents, under pressures up to 1400 kPa and at temperatures up to 200 deg C.Advantages and applications of the CMR are discussed, along with the rationale for the design.Reactions carried out with the CMR included nucleophilic substitution, addition, esterification, transesterification, acetalization, amidation, base- and acid-catalyzed hydrolysis, isomerization, decarboxylation, and elimination.Name reactions included the Michael addition, Hofmann degradation, Williamson ether synthesis, and the Mannich, Finkelstein, Baylis-Hillman, and Knoevenagel reactions.
- Cablewski, Teresa,Faux, Alan F.,Strauss, Christopher R.
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p. 3408 - 3412
(2007/10/02)
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- Esterification of Aromatic Carboxylic Acids with Alcohols Using 2-Chloro-3,5-dinitropyridine as a Condensing Agent
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The reaction of 2-chloro-3,5-dinitropyridine (CDNP) with carboxylic acids and alcohols was examined, and it was found that CDNP was a useful condensing agent.Various esters were prepared in good yields.
- Takimoto, Seiji,Abe, Naomi,Kodera, Yasushi,Ohta, Hiroshi
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p. 639 - 640
(2007/10/02)
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