Theoretical study on the reaction mechanism for the hydrolysis of esters and amides under acidic conditions

Tetrahedron ◽  
2007 ◽  
Vol 63 (5) ◽  
pp. 1264-1269 ◽  
Author(s):  
Kenzi Hori ◽  
Yutaka Ikenaga ◽  
Kouichi Arata ◽  
Takanori Takahashi ◽  
Kenji Kasai ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Theoretical Study ◽  
Acidic Conditions ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

scholarly journals Thermodynamic Study of Hydrolysis Reactions in Aqueous Solution fromAb InitioPotential and Molecular Dynamics Simulations

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
S. Tolosa ◽  
A. Hidalgo ◽  
J. A. Sansón
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Free Energy ◽  
Reaction Mechanism ◽  
Molecular Dynamics Simulations ◽  
Infinite Dilution ◽  
Theoretical Study ◽  
Water Model ◽  
Dynamics Simulations ◽  
Hydrolysis Of

A procedure for the theoretical study of chemical reactions in solution by means of molecular dynamics simulations of aqueous solution at infinite dilution is described usingab initiosolute-solvent potentials and TIP3P water model to describe the interactions. The procedure is applied to the study of neutral hydrolysis of various molecules (HCONH2, HNCO, HCNHNH2, and HCOOCH3) via concerted and water-assisted mechanisms. We used the solvent as a reaction coordinate and the free energy curves for the calculation of the properties related with the reaction mechanism, namely, reaction and activation energies.

Hydrolysis of a neonicotinoid: a theoretical study on the reaction mechanism of dinotefuran

2017 ◽  
Vol 29 (1) ◽  
pp. 315-325 ◽  
Author(s):  
Rong Chen ◽  
Hui Yin ◽  
Chaoqing Zhang ◽  
Xiaoling Luo ◽  
Guoming Liang
Keyword(s):  
Reaction Mechanism ◽  
Theoretical Study ◽  
Hydrolysis Of

scholarly journals Theoretical Study of the Reaction Mechanism and Role of Water Clusters in the Gas-Phase Hydrolysis of SiCl4

2003 ◽  
Vol 107 (41) ◽  
pp. 8705-8713 ◽  
Author(s):  
Stanislav K. Ignatov ◽  
Petr G. Sennikov ◽  
Alexey G. Razuvaev ◽  
Lev A. Chuprov ◽  
Otto Schrems ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Gas Phase ◽  
Theoretical Study ◽  
Water Clusters ◽  
Hydrolysis Of

Theoretical Study of the Reaction Mechanism and Role of Water Clusters in the Gas-Phase Hydrolysis of SiCl4.

ChemInform ◽  
2004 ◽  
Vol 35 (1) ◽  
Author(s):  
Stanislav K. Ignatov ◽  
Petr G. Sennikov ◽  
Alexey G. Razuvaev ◽  
Lev A. Chuprov ◽  
Otto Schrems ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Gas Phase ◽  
Theoretical Study ◽  
Water Clusters ◽  
Hydrolysis Of

The Effects of Amines on the Esterase Activities of Thrombin and Thrombokinase and on Several Clotting Tests

1974 ◽  
Vol 31 (02) ◽  
pp. 309-318
Author(s):  
Phyllis S Roberts ◽  
Raphael M Ottenbrite ◽  
Patricia B Fleming ◽  
James Wigand
Keyword(s):  
Choline Chloride ◽  
Polymerization Process ◽  
Ammonium Bromide ◽  
Bovine Thrombin ◽  
One Stage ◽  
Human Proteins ◽  
Rate Of Hydrolysis ◽  
The One ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

Summary1. Choline chloride, 0.1 M (in 0.25 M Tris. HCl buffer, pH 7.4 or 8.0, 37°), doubles the rate of hydrolysis of TAME by bovine thrombokinase but has no effect on the hydrolysis of this ester by either human or bovine thrombin. Only when 1.0 M or more choline chloride is present is the hydrolysis of BAME by thrombokinase or thrombin weakly inhibited. Evidence is presented that shows that these effects are due to the quaternary amine group.2. Tetramethyl ammonium bromide or chloride has about the same effects on the hydrolysis of esters by these enzymes as does choline chloride but tetra-ethyl, -n.propyl and -n.butyl ammonium bromides (0.1 M) are stronger accelerators of the thrombokinase-TAME reaction and they also accelerate, but to a lesser degree, the thrombin-TAME reaction. In addition, they inhibit the hydrolysis of BAME by both enzymes. Their effects on these reactions, however, do not follow any regular order. The tetraethyl compound is the strongest accelerator of the thrombokinase-TAME reaction but the tetra-ethyl and -butyl compounds are the strongest accelerators of the thrombin-TAME reaction. The ethyl and propyl compounds are the best (although weak) inhibitors of the thrombokinase-BAME and the propyl compound of the thrombin-BAME reactions.3. Tetra-methyl, -ethyl, -n.propyl and -n.butyl ammonium bromides (0.01 M) inhibit the clotting of fibrinogen by thrombin (bovine and human proteins) at pH 7.4, imidazole or pH 6.1, phosphate buffers and they also inhibit, but to a lesser degree, a modified one-stage prothrombin test. In all cases the inhibition increases regularly as the size of the alkyl group increases from methyl to butyl. Only the ethyl com pound (0.025 M but not 0.01 M), however, significantly inhibits the polymerization of bovine fibrin monomers. It was concluded that inhibition of the fibrinogen-thrombin and the one-stage tests by the quaternary amines is not due to any effect of the com pounds on the polymerization process but probably due to inhibition of thrombin’s action on fibrinogen by the quaternary amines.

Theoretical study of the ketonization reaction mechanism of acetic acid over SiO2

2009 ◽  
Author(s):  
Mendel Fleisher ◽  
E. Lukevics ◽  
L. Leite ◽  
D. Jansone ◽  
K. Edolfa ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Theoretical Study

Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

2003 ◽  
Vol 68 (10) ◽  
pp. 2019-2031 ◽  
Author(s):  
Markéta Zukalová ◽  
Jiří Rathouský ◽  
Arnošt Zukal
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Oxide ◽  
Sodium Metasilicate ◽  
Spherical Particles ◽  
Structure Directing Agent ◽  
Inorganic Species ◽  
Poly Ethylene Oxide ◽  
Acidic Conditions ◽  
Poly Ethylene ◽  
Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

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