Intermolecular and Intramolecular Friedel‐Crafts Acylation of Carboxylic Acids using Binary Ionic Liquids: An Experimental and Computational Study

2022 ◽  
Vol 7 (2) ◽  
Author(s):  
Hai Truong Nguyen ◽  
Nghia Le ◽  
Yoshiyuki Kawazoe ◽  
Nguyen‐Nguyen Pham‐Tran ◽  
Phuong Hoang Tran
Keyword(s):  
Ionic Liquids ◽  
Carboxylic Acids ◽  
Computational Study

A computational study on the mechanism of ynamide-mediated amide bond formation from carboxylic acids and amines

2017 ◽  
Vol 15 (30) ◽  
pp. 6367-6374 ◽  
Author(s):  
Song-Lin Zhang ◽  
Hai-Xing Wan ◽  
Zhu-Qin Deng
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Bond Formation ◽  
Amide Bond ◽  
Reactivity Pattern ◽  
Amide Bond Formation ◽  
Coupling Reagent ◽  
Catalytic Effects ◽  
Acid Substrate

A detailed computational study is presented on the reaction mechanism of ynamide-mediated condensation of carboxylic acids with amines to produce amides, which elucidates the reactivity pattern of the coupling reagent ynamide and discloses crucial bifunctional catalytic effects of the carboxylic acid substrate during aminolysis.

Redshift or Adduct Stabilization—A Computational Study of Hydrogen Bonding in Adducts of Protonated Carboxylic Acids

2009 ◽  
Vol 15 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Solveig Gaarn Olesen ◽  
Steen Hammerum
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Bond Strength ◽  
Bond Length ◽  
Carboxylic Acids ◽  
Computational Study ◽  
Proton Affinities ◽  
Oh Groups ◽  
Hydrogen Bond Strength ◽  
Length Changes

It is generally expected that the hydrogen bond strength in a D–H•••A adduct is predicted by the difference between the proton affinities (Δ PA) of D and A, measured by the adduct stabilization, and demonstrated by the infrared (IR) redshift of the D–H bond stretching vibrational frequency. These criteria do not always yield consistent predictions, as illustrated by the hydrogen bonds formed by the E and Z OH groups of protonated carboxylic acids. The Δ PA and the stabilization of a series of hydrogen bonded adducts indicate that the E OH group forms the stronger hydrogen bonds, whereas the bond length changes and the redshift favor the Z OH group, matching the results of NBO and AIM calculations. This reflects that the thermochemistry of adduct formation is not a good measure of the hydrogen bond strength in charged adducts, and that the ionic interactions in the E and Z adducts of protonated carboxylic acids are different. The OH bond length and IR redshift afford the better measure of hydrogen bond strength.

scholarly journals Simultaneous upgrading of biomass-derived sugars to HMF/furfural via enzymatically isomerized ketose intermediates

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Wei Wang ◽  
Ashutosh Mittal ◽  
Heidi Pilath ◽  
Xiaowen Chen ◽  
Melvin P. Tucker ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Reaction Time ◽  
Carboxylic Acids ◽  
Chemical Process ◽  
Sodium Borate ◽  
Side Reactions ◽  
Acid Catalysts ◽  
Hydroxymethyl Furfural ◽  
Dehydration Reactions ◽  
Biphasic Systems

Abstract Background Recently, exploring fermentative or chemical pathways that convert biomass-derived sugars to fuels/chemicals has attracted a lot of interest from many researchers. We are investigating a hydrocarbon pathway from mixed sugars via 5-hydroxymethyl furfural (HMF) and furfural intermediates. To achieve this goal, we must first convert glucose and xylose to HMF and furfural in favorable yields. Current processes to produce HMF/furfural generally involve the use of acid catalysts in biphasic systems or solvents such as ionic liquids. However, the yield from transforming glucose to HMF is lower than the yield of furfural from xylose. Results In this study, we present an efficient chemical pathway simultaneously transforming glucose and xylose to HMF and furfural via ketose intermediates, i.e., fructose and xylulose, which were generated from glucose and xylose via enzymatic isomerization. In the enzymatic isomerization, by adding sodium borate to complex with the ketoses, xylose conversion reached equilibrium after 2 h with a conversion of 91% and glucose conversion reached 84% after 4 h. By enzymatically isomerizing the aldoses to ketoses, the following dehydration reactions to HMF and furfural could be performed at low process temperatures (i.e., 110–120 °C) minimizing the side reactions of the sugars and limiting the degradation of furfurals to humins and carboxylic acids. At 120 °C, pH 0.5, and 15 min reaction time, mixed ketose sugars were converted to HMF and furfural in yields of 77% and 96%, respectively (based on starting aldose concentrations). Conclusion Taken together, our results demonstrate that this combined biological and chemical process could be an effective pathway to simultaneously convert biomass-derived glucose and xylose to HMF and furfural, for use as intermediates in the production of hydrocarbons.

Synthesis and Computational Study of Phosphorus Ionic Liquids

2010 ◽  
Vol 185 (12) ◽  
pp. 2464-2471
Author(s):  
Hossein Tavakol ◽  
Gita Gaimech ◽  
Shahryar Ghammamy ◽  
Gholamreza Rezaei Bebahani
Keyword(s):  
Ionic Liquids ◽  
Computational Study
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