Use Of Acid Catalysts Research Articles

Micellar-System-Mediated Direct Fluorination of Ketones in Water

A micellar system was developed and applied for direct regioselective fluorination of a variety of cyclic and acyclic ketones to α-fluoroketones in water as reaction medium with Selectfluor F-TEDA-BF 4 as fluorinating reagent. The inexpensive ionic amphiphile sodium dodecyl sulfate (SDS) was found to be an excellent promoter for fluorofunctionalization of hydrophobic ketones without prior activation or use of acid catalysts.

Catalytic reduction of NH4NO3 by NO: Effects of solid acids and implications for low temperature DeNOx processes

Ammonium nitrate is thermally stable below 250°C and could potentially deactivate low temperature NOx reduction catalysts by blocking active sites. It is shown that NO reduces neat NH4NO3 above its 170°C melting point, while acidic solids catalyze this reaction even at temperatures below 100°C. NO2, a product of the reduction, can dimerize and then dissociate in molten NH4NO3 to NO++NO3−, and may be stabilized within the melt as either an adduct or as HNO2 formed from the hydrolysis of NO+ or N2O4. The other product of reduction, NH4NO2, readily decomposes at ≤100°C to N2 and H2O, the desired end products of DeNOx catalysis. A mechanism for the acid catalyzed reduction of NH4NO3 by NO is proposed, with HNO3 as an intermediate. These findings indicate that the use of acidic catalysts or promoters in DeNOx systems could help mitigate catalyst deactivation at low operating temperatures (<150°C).

Green Protocol for the O—H Insertion of α‐Diazoketones with Alcohols and Water Using Ionic Liquid [Bmim]BF4.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Green Protocol for the O–H Insertion of α-Diazoketones with Alcohols and Water Using Ionic Liquid [Bmim]BF4

Abstract α-Diazoketones undergo readily O–H insertion reactions with alcohols and water in hydrophilic [bmim]BF4 ionic liquid in the absence of any acid catalyst to furnish α-alkoxy and α-hydroxy ketones in excellent yields under neutral conditions. The recovered ionic liquid can be easily reused in four to five cycles with consistent in activity. The use of ionic liquid helps to avoid the use of acid catalysts as well as environmentally unfavorable volatile organic solvents.

Enzymatic synthesis of carbonate monomers and polycarbonates.

Diphenyl carbonate is an attractive monomer for copolymerization with Bisphenol-A to produce the strong, high melting polycarbonate, Bisphenol-A Polycarbonate. Diphenyl carbonate is an ideal candidate for this polymerization as the phenols constitute good leaving groups during polymerization. Industrially, diphenyl carbonate is produced via the phosgenation of a phenolic sodium salt. Using phosgene creates additional safety hazards as well as concerns in treating or disposing of the reaction by-products. The enzymatic synthesis of diphenyl carbonate via alcoholysis of dimethyl carbonate by phenol is presented. While the process is environmentally benign and eliminates the considerable safety issues related to the use of phosgene, phenol is a poor nucleophile and conversion to diphenyl carbonate is limited. Enzyme catalyzed condensation polymerization of carbonate monomers and diols is a more feasible and direct enzymatic route to polycarbonate. We describe an AA-BB condensation polymerization to make polycarbonates using enzymes at ambient conditions. Molecular weights of up to 8, 500 MW are achieved. Unlike the industrial polymerization, this process is performed without the use of acid catalysts, significant energy input, or high temperature or pressure.

Reactions of Allyl Phenyl Ether in High-Temperature Water with Conventional and Microwave Heating

In a systematic study, allyl phenyl ether (1) was heated in water for 1 h at temperatures of 180 degrees C and above. Parallel experiments were conducted with a conventionally heated autoclave and a recently developed microwave batch reactor. Relatively modest temperature differences resulted in diverse product distributions, and these were independent of the method of heating. Maximum conversion of 1 to 2-allylphenol occurred at 200 degrees C (56%) and to 2-methyl-2,3-dihydrobenzofuran at 250 degrees C (72%). Although 2-(2-hydroxyprop-1-yl)phenol comprised less than 1% of the product mixture at both 180 and 260 degrees C, it accounted for 37% at 230 degrees C. The reaction sequence was investigated by heating intermediates individually at selected temperatures up to 290 degrees C. Hydration of 2-allylphenol to 2-(2-hydroxyprop-1-yl)phenol was partially reversible. The work showed that high-temperature water constitutes an environmentally benign alternative to the use of acid catalysts or organic solvents and offers scope for interconversion of alcohols and alkenes.

ポリ（２，５‐フランジイルビニレン）フィルムの合成

Preparation of high quality poly (2.5-thienylenevinylene)(PTV) films via organic solvent-soluble precursor polymer was investigated. The polymerization conditions for the preparation of stable and processable PTV precursor polymers were described. The perfect conversion from precursor polymer to PTV was rea1ized by use of acid catalyst. The conversion temperature was reduced down to 80℃ and no side reaction occurred, when a small amount of hydrochloric acid was supplied in vapor phase. CP/MAS 13C-NMR spectra showed that the fully converted PTV had no chemical defect originating from sp3-hybridized carbon. The structural defect in fully converted PTV was ana1yzed from UV-Vis and infrared absorption spectra. Those spectra suggested that the cis-vinylene linkage was produced for reducing chain strain．

Alkene oligomerization

This paper reviews the oligomerization of alkenes. The thermodynamics and kinetics of the reaction and the use of both homogeneous and heterogeneous catalysts is discussed. Particular attention is given to the use of acid catalysts, especially zeolites, and homogeneous and heterogeneous nickel catalysts.

Catalytic methods of synthesizing polybenzazoles. Review

The review is concerned with the analysis of the published data on the synthesis of polybenzazoles (polybenzoxazoles, polybenzimidazoles, polybenzthiazoles) in presence of acid catalysts. It is shown that all the main methods of synthesizing polybenzazoles — “Marvel reaction”, “Iwakura reaction” two-stage polycyclocondensation, high temperature polycyclocondensation in organic solvents, reductive polyheterocyclization—contain in themselves elements of catalytic polycyclocondensation. From a number of examples it is shown that the use of acid catalysts allows one not only to lower the temperature and shorten the duration of synthesis of the polybenzazoles but also to obtain polymers with an essentially new complex of properties.

Preparation of crystalline polystyrenes by use of acid catalysts

Journal of Polymer ScienceVolume 31, Issue 122 p. 215-217 Letter to the Editor Preparation of crystalline polystyrenes by use of acid catalysts H. Z. Friedlander, H. Z. Friedlander Stamford Laboratories, Research Division, American Cyanamid Company, Stamford, ConnecticutSearch for more papers by this authorW. M. Thomas, W. M. Thomas Stamford Laboratories, Research Division, American Cyanamid Company, Stamford, ConnecticutSearch for more papers by this author H. Z. Friedlander, H. Z. Friedlander Stamford Laboratories, Research Division, American Cyanamid Company, Stamford, ConnecticutSearch for more papers by this authorW. M. Thomas, W. M. Thomas Stamford Laboratories, Research Division, American Cyanamid Company, Stamford, ConnecticutSearch for more papers by this author First published: August 1958 https://doi.org/10.1002/pol.1958.1203112237Citations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume31, Issue122August 1958Pages 215-217 RelatedInformation