Kinetic medium effects. III. Solvent effects on A1 and A2 Hydrolyses in water-dimethyl sulphoxide mixtures

1967 ◽  
Vol 20 (9) ◽  
pp. 1815 ◽  
Author(s):  
BG Cox ◽  
PT McTigue
Keyword(s):  
Ethyl Acetate ◽  
Solvent Effect ◽  
Activity Coefficients ◽  
Solvent Effects ◽  
Butyl Acetate ◽  
Solvent System ◽  
Solvent Composition ◽  
Dimethyl Sulphoxide ◽  
Medium Effects ◽  
System Activity

The relative rates of the concurrent A1 and A2 hydrolyses of t-butyl acetate have been measured as a function of solvent composition in water-dimethyl sulphoxide (DMSO) mixtures. A large difference in solvent effect is observed, which correlates well with observed solvent effects on ethyl acetate (A2) and acetal (Al) hydrolyses in the same solvent system. Activity coefficients have been measured for t-butyl acetate, ethyl acetate, and acetal in various water-DMSO mixtures.

Kinetic Solvent Effects in Organic Reactions

2017 ◽  
Author(s):  
Belinda Slakman ◽  
Richard West
Keyword(s):  
Solvent Effect ◽  
Reaction Kinetics ◽  
Computational Methods ◽  
High Throughput ◽  
Kinetic Modeling ◽  
Solvent Effects ◽  
Reaction Rates ◽  
Prior Work ◽  
Solvent Phase ◽  
High Throughput Manner

<div> <div> <div> <p>This article reviews prior work studying reaction kinetics in solution, with the goal of using this information to improve detailed kinetic modeling in the solvent phase. Both experimental and computational methods for calculating reaction rates in liquids are reviewed. Previous studies, which used such methods to determine solvent effects, are then analyzed based on reaction family. Many of these studies correlate kinetic solvent effect with one or more solvent parameters or properties of reacting species, but it is not always possible, and investigations are usually done on too few reactions and solvents to truly generalize. From these studies, we present suggestions on how best to use data to generalize solvent effects for many different reaction types in a high throughput manner. </p> </div> </div> </div>

The Flavor Property of Soft Cheese Fermented by Two Stains of Streptococcus thermophilus and Made of Reconstituted Milk

2011 ◽  
Vol 396-398 ◽  
pp. 1536-1540
Author(s):  
Yan Hua Li ◽  
Lan Wei Zhang ◽  
Wei Jun Wang ◽  
Li Li Zhang ◽  
Xue Han ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Butyl Acetate ◽  
Streptococcus Thermophilus ◽  
Acetate Methyl ◽  
Soft Cheese ◽  
Significant Difference ◽  
Cheese Volatiles ◽  
Methyl Butyrate ◽  
Reconstituted Milk ◽  
The Impact

The effect of reconstituted milk inoculation with Streptococcus thermophilus TM11 and Streptococcus thermophilus SP 1.1 on soft cheese volatiles was investigated. The impact flavors of 2,3-butanedione, 2,3-pentanedione, ethyl acetate, methyl butyrate, ethyl butyrate, butyl acetate and butyric acid were only detected in the fermented cheeses. Levels of diketones were higher in the cheeses fermented by mixed cultures than single culture, while levels of esters except ethyl acetate and butyl acetate showed an opposite tendency. There was significant difference in the levels of 2-hexenal and 2-nonenal among the cheeses. Other compounds originated from lipid oxidation, Strecker degradation, biosynthesis and forages were not significantly influenced by milk inoculation with Streptococcus thermophilus.

Solvent effects on complex formation: Cobalt(II)thiourea in ethyl acetate, propanol, propylene carbonate

1983 ◽  
Vol 75 ◽  
pp. 237-240 ◽  
Author(s):  
Ugo Biader Ceipidor ◽  
Vicenzo Carunchio ◽  
Anna Maria Girelli ◽  
Antonella Messina
Keyword(s):  
Complex Formation ◽  
Ethyl Acetate ◽  
Propylene Carbonate ◽  
Solvent Effects

scholarly journals Areas of energy advantage for flowsheets of separation modes for mixtures containing components with similar volatilities

2020 ◽  
Vol 15 (3) ◽  
pp. 7-20
Author(s):  
M. E. Peshekhontseva ◽  
M. A. Maevskiy ◽  
I. S. Gaganov ◽  
A. V. Frolkova
Keyword(s):  
Ethyl Acetate ◽  
Butyl Acetate ◽  
Energy Savings ◽  
Equilibrium Diagram ◽  
Distribution Coefficients ◽  
Local Composition ◽  
Component Distribution ◽  
Boiling Points ◽  
Relative Errors ◽  
Energy Advantage

Objectives. The conditions for the effective application of the sharp distillation technique (without a component distributed between the distillate and bottom flows) for the separation of quaternary zeotropic mixtures containing components with similar volatilities were determined. The area of energy advantage for the flowsheet based on the preliminary fractionation of the mixture, compared with the flowsheet, the first distillation column of which works based on the indirect separation mode, was identified for an ethyl acetate–benzene–toluene–butyl acetate system. Energy savings of up to 20% were achieved. The direct and indirect distillation modes can become competitive when the point of the original composition is located near single K-surfaces or in a region with a different ratio of distribution coefficients. Sharp distillation is not suitable for the separation of a mixture containing a pair of components exhibiting relative unity volatility with medium boiling points.Methods. The mathematical modeling in the Aspen Plus V.10.0 software package was chosen as the research method. The simulation was based on the Wilson local composition equation. The relative errors in the description of the phase equilibrium did not exceed 3%.Results. The structure of the vapor–liquid equilibrium diagram and diagram of surfaces of the unit component distribution coefficients were studied for the ethyl acetate–benzene–toluenebutyl acetate and acetone–toluene–butyl acetate–o-xylene systems. Flowsheets based on the sharp, indirect (both systems), or direct (second system) distillation modes were proposed. The distillation process was simulated, and the parameters of the column work were determined (the quality of the substances meets the State Standard requirements of the Russian Federation for minimal energy consumption).Conclusions. Recommendations regarding the use of sharp distillation for the separation of quaternary mixtures containing components with similar volatilities were devised.

Kinetic medium effects. IV. Transition state activity coefficients in mixed solvents

1972 ◽  
Vol 25 (4) ◽  
pp. 777 ◽  
Author(s):  
PT McTigue ◽  
AR Watkins
Keyword(s):  
Transition State ◽  
Activity Coefficients ◽  
Mixed Solvents ◽  
State Theory ◽  
Medium Effects ◽  
State Activity ◽  
Medium Activity ◽  
Solvent Systems ◽  
Kinetics Of ◽  
Hydrolysis Of

The kinetics of acid hydrolysis of a number of aliphatic acetals have been studied in dimethyl sulphoxide-water and dioxan-water mixtures. Where possible, experimentally measured medium activity coefficients for the acetals in the solvent systems have been used in order to calculate the transition state activity coefficients as a function of solvent composition. These activity coefficients are compared with those calculated for the transition states of other hydrolytic reactions, and with the known activity coefficients of some stable ions. The results show no features inconsistent with the assumptions of transition state theory.

Justicia beddomei, a source of comprehensive vasicinone production

2019 ◽  
Vol 66 (3-4) ◽  
pp. 213-219 ◽  
Author(s):  
Jitendriya Panigrahi ◽  
Saikat Gantait ◽  
Illa C. Patel
Keyword(s):  
Silica Gel ◽  
Butyl Acetate ◽  
Methanolic Extract ◽  
Dry Weight ◽  
Solvent System ◽  
Validation Data ◽  
Plant Parts ◽  
System Validation ◽  
Tlc Plates

The present study formulates a method for comprehensive production of vasicinone, a quinazoline alkaloid, from multiple plant parts of in vitro and in-field-grown Justicia beddomei. HPTLC analysis of plant parts was executed with methanolic extract using toluene: butanol: butyl acetate (9:0.5:0.5; v/v/v) as the solvent system. Validation of methodology was accomplished using TLC plates (silica gel 60 F254-pre-coated aluminium sheet) following the ICH manual to maintain accuracy, precision and repeatability with a linearity ranging 2–6 μg/spot. Validation data offers precision to the methodology adapted in the present study (LOD 1 μg/spot and LOQ 3 μg/spot). It was evident that in vitro samples produced relatively higher levels of vasicinone than that of their in-field counterparts. The highest vasicinone (2.07±0.025% of dry weight) production was quantified from in vitro stem, signifying a new resource for the production of vasicinone from identified parts of in vitro and in-field propagated J. beddomei plants.

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