Catalyzed Alkaline Hydrolysis of Substituted Phenyl Acetates

1993 ◽  
Vol 58 (8) ◽  
pp. 1798-1802 ◽  
Author(s):  
Jiří Kulič ◽  
Aleš Ptáček
Keyword(s):  
Alkaline Medium ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Hexadecyltrimethylammonium Bromide ◽  
Hammett Equation ◽  
First Order ◽  
Order Rate ◽  
Iodosobenzoic Acid ◽  
Hydrolysis Of

2-Iodosobenzoic acid forming strong nucleophile in alkaline medium - 1-oxido-1,2-benziodoxol-3(1H)-one, was used as a catalyst of alkaline hydrolysis of substituted phenyl acetates (4-NO2, 3-NO2, 3-Cl, 4-Br, H, 4-CH3, 3-CH3, 4-OCH3, 3-OCH3) in the presence of hexadecyltrimethylammonium bromide as a micellar agent. It was found that the observed first-order rate constants kobs can be correlated by the Hammett equation: log kobs = (-3.29 ± 0.03) + (1.77 ± 0.001) σ.

scholarly journals Kinetic Evidence for Near Irreversible Nonionic Micellar Entrapment ofN-(2′-Methoxyphenyl)phthalimide (1) under the Typical Alkaline Reaction Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
M. Niyaz Khan ◽  
Yoke-Leng Sim ◽  
Azhar Ariffin
Keyword(s):  
Kinetic Analysis ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Total Concentration ◽  
Reaction Conditions ◽  
First Order ◽  
Order Rate ◽  
Alkaline Reaction ◽  
Pseudo First Order ◽  
Hydrolysis Of

The values of pseudo-first-order rate constants (kobs) for alkaline hydrolysis of1, obtained at 1.0 mM NaOH and withinCmEnT(total concentration ofCmEn) range of 3.0–5.0 mM forC12E23and 10–20 mM forC18E20, fail to obey pseudophase micellar (PM) model. The values of the fraction of near irreversibleCmEnmicellar trapped1molecules (FIT1) vary in the range ~0–0.75 forC12E23and ~0–0.83 forC18E20under such conditions. The values ofFIT1become 1.0 at ≥10 mMC12E23and 50 mMC18E20. Kinetic analysis of the observed data at ≥10 mMC12E23shows near irreversible micellar entrapment of1molecules under such conditions.

A kinetic standard for precise calibration of spectrophotometer cell temperature.

1981 ◽  
Vol 27 (5) ◽  
pp. 753-755 ◽  
Author(s):  
P A Adams ◽  
M C Berman
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Cell Temperature ◽  
First Order ◽  
Order Rate ◽  
Acid Catalyzed ◽  
Pseudo First Order ◽  
Hydrolysis Of

Abstract We describe a simple, highly reproducible kinetic technique for precisely measuring temperature in spectrophotometric systems having reaction cells that are inaccessible to conventional temperature probes. The method is based on the temperature dependence of pseudo-first-order rate constants for the acid-catalyzed hydrolysis of N-o-tolyl-D-glucosylamine. Temperatures of reaction cuvette contents are measured with a precision of +/- 0.05 degrees C (1 SD).

KINETICS OF THE AQUEOUS ALKALINE HOMOGENOUS HYDROLYSIS OF HIGH EXPLOSIVE 1, 3,5,7-TETRAAZA- 1, 3,5,7-TETRANITROCYCLOOCTANE (HMX)

1994 ◽  
Vol 30 (3) ◽  
pp. 53-61 ◽  
Author(s):  
Harro M. Heilmann ◽  
Michael K. Stenstrom ◽  
Rolf P. X. Hesselmann ◽  
Udo Wiesmann
Keyword(s):  
Temperature Dependence ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Elevated Temperatures ◽  
Second Order ◽  
Order Rate ◽  
Subsequent Calculation ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Order Rate Equation

In order to get basic data for the design of a novel treatment scheme for high explosives we investigated the kinetics for the aqueous alkaline hydrolysis of 1,3,5,7-tetraaza-1,3,5,7-tetranitrocyclooctane (HMX) and the temperature dependence of the rate constants. We used an HPLC procedure for the analysis of HMX. All experimental data could be fit accurately to a pseudo first-order rate equation and subsequent calculation of second-order rate constants was also precise. Temperature dependence could be modeled with the Arrhenius equation. An increase of 10°C led to an average increase in the second-order rate constants by the 3.16 fold. The activation energy of the second-order reaction was determined to be 111.9 ±0.76 kJ·moJ‒1. We found the alkaline hydrolysis to be rapid (less than 2.5% of the initial HMX-concentration left after 100 minutes) at base concentrations of 23 mmol oH‒/L and elevated temperatures between 60 and 80°C.

Acyl Transfer Isomerization of Glycerol 1,2-Dibutyrate and Propane-1,2-diol 1-Butyrate

1998 ◽  
Vol 51 (6) ◽  
pp. 455 ◽  
Author(s):  
Charmian J. O'Connor ◽  
Richard H. Barton
Keyword(s):  
Rate Constants ◽  
Equilibrium Mixture ◽  
Acyl Transfer ◽  
Product Mix ◽  
First Order ◽  
Order Rate ◽  
Pregastric Lipase ◽  
Water Ph ◽  
Emulsion Systems ◽  
Hydrolysis Of

The speciation of mixed butyrylglycerols (glycerol butyrates) and propanediol butyrate esters in the product mix from lamb pregastric lipase-catalysed hydrolysis of tributyrylglycerol and propane-1,2-diol dibutyrate has been examined by 13C n.m.r. spectroscopy. Samples from the quenched reaction mixture were extracted and allowed to stand in emulsion systems made up in bis tris propane buffer or water, pH 7·0, and in the absence of enzyme. There is clear evidence of uncatalysed conversion of rac-1,2-dibutyrylglycerol into the 1,3-isomer to form an equilibrium mixture containing c. 60–67% 1,3-isomer, and of conversion of propane-1,2-diol 1-butyrate into propane-1,2-diol 2-butyrate to form an equilibrium mixture containing c. 67% 2-monoester. Conversion kinetics to reach equilibrium are first order. Rate constants for acyl transfer of the diacylglycerol are 0·48 h-1 (in water) and 0·68 h-1 (in buffer) at 50°C, while those for acyl transfer of the 1-monoester are 0·72 h-1 (50°C) and 0·35 h-1 (35°C).

Electrochemistry of Ruthenium Ammine Complexes

1975 ◽  
Vol 53 (19) ◽  
pp. 2922-2929 ◽  
Author(s):  
C. M. Elson ◽  
I. J. Itzkovitch ◽  
J. McKenney ◽  
John A. Page
Keyword(s):  
Cyclic Voltammetry ◽  
Rate Constants ◽  
Reduction Step ◽  
Methane Sulfonate ◽  
Ammine Complexes ◽  
Chloro Complexes ◽  
First Order ◽  
Order Rate ◽  
Electron Reduction ◽  
Hydrolysis Of

The electrochemistry of ruthenium(III) penta- and tetraammine chloro complexes has been investigated. In each case, the ruthenium(III) species was found to undergo an initial one electron reduction step, followed by hydrolysis of the chloride(s) in the ruthenium(II) product. The rate constants for the substitution steps were evaluated by cyclic voltammetry. An aqueous 0.30 M methane sulfonate electrolyte of pH 2.0 was used at 25 °C.Values for the reversible "E1/2" (V υs. SCE) and first order rate constants for the (stepwise) replacement of the Cl− are: Ru(NH3)5Cl+, −0.282 V and 17 s−1; cis-Ru(NH3)4Cl2+, −0.328 V, 80 s−1, and 5 s−1; trans-Ru(NH3)4Cl2+, −0.412 V, 2 s−1, and 0.4 s−1.The electrochemistry of Ru(NH3)5SO22+was also investigated. In a 0.10 M CH3SO3H – 0.20 M CH3SO3Na electrolyte the ruthenium(II) species was found to undergo an initial one electron oxidation step with "E1/2" = +0.50 V, followed by a slow hydrolysis of the SO2 in the ruthenium(III) product with k = 2.4 × 10−2 s−1 at 25 °C.

Octahedral cobalt(III) complexes of the chloropentammine type. XIX. The preparation, properties, and reactions of some Chlorobenzylaminebis-(ethylenediamine)cobalt(III) salts and related complexes

1969 ◽  
Vol 22 (9) ◽  
pp. 1869 ◽  
Author(s):  
SC Chan ◽  
OW Lau
Keyword(s):  
Rate Constants ◽  
Open Chain ◽  
First Order ◽  
Benzyl Radical ◽  
Order Rate ◽  
Visible Spectra ◽  
Rate Of Reaction ◽  
Inductive Effects ◽  
Steric Factors ◽  
Hydrolysis Of

Salts of one isomeric series of chlorobenzylaminebis(ethylenediamine)- cobalt-(III) type of cations have been prepared using a variety of benzylamine derivatives as ligands. They are tentatively assigned a cis-configuration on the basis of their visible spectra. The first- order rate constants for their solvolytic aquation have been measured. Both resonance contributions and steric factors from the benzyl radical, as well as inductive effects of its substituents, all have negligibly small influences on the rate of reaction. The second-order rate constants for the hydrolysis of these cations by base have also been determined. The labilizing powers of the benzylamine ligands in this reaction are very similar to those of open-chain aliphatic amines, and significantly different from those of aromatic amines. To see if reactivities depend on the distance of separation between cobalt and the benzene ring, the experiments are extended to the chloro(β- phenylethylamine)bis(ethylenediamine)cobalt(III) type of complexes.

Alkaline Hydrolysis of Substituted Phenyl Acetates Catalyzed by Quaternary Ammonium Salts

1993 ◽  
Vol 58 (12) ◽  
pp. 2891-2895 ◽  
Author(s):  
Jiří Kulič ◽  
Jiří Sussenbek ◽  
Aleš Ptáček
Keyword(s):  
Ammonium Chloride ◽  
Alkaline Hydrolysis ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Ammonium Bromide ◽  
Hexadecyltrimethylammonium Bromide ◽  
Rate Data ◽  
Hammett Equation ◽  
Efficient Catalyst ◽  
Hydrolysis Of

Alkaline hydrolysis if the phenyl acetates CH3COOC6H4X (X = 4-NO2, 3-NO2, 3-Cl, H, 4-CH3, 3-CH3, and 4-OCH3) in the presence of hexadecyltris(2-hydroxyethyl)ammonium chloride, bis(2-hydroxyethyl)hexadecyl(methyl)ammonium bromide, and hexadecyltrimethylammonium bromide has been studied. Comparison of the rates of the hydrolysis for the above tenzides showed that the most efficient catalyst is the hexadecyltris(2-hydroxyethyl)ammonium chloride. In all cases, the rate data correlated well with structure effects by the Hammett equation.

scholarly journals Optimization and a Kinetic Study on the Acidic Hydrolysis of Dialkyl α-Hydroxybenzylphosphonates

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3793
Author(s):  
Nikoletta Harsági ◽  
Zita Rádai ◽  
Áron Szigetvári ◽  
János Kóti ◽  
György Keglevich
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Acidic Hydrolysis ◽  
First Order ◽  
Order Rate ◽  
Rate Determining Step ◽  
Pseudo First Order ◽  
Hydrolysis Of ◽  
Electron Withdrawing Substituents

The two-step acidic hydrolysis of α-hydroxybenzylphosphonates and a few related derivatives was monitored in order to determine the kinetics and to map the reactivity of the differently substituted phosphonates in hydrolysis. Electron-withdrawing substituents increased the rate, while electron-releasing ones slowed down the reaction. Both hydrolysis steps were characterized by pseudo-first-order rate constants. The fission of the second P-O-C bond was found to be the rate-determining step.

Effect of OH- Concentration on Alkaline Hydrolysis of Diphenyl (4-Nitrophenyl) Phosphate Catalyzed by 2-Iodosobenzoic and 3-Iodoso-2-naphthoic Acids

1994 ◽  
Vol 59 (5) ◽  
pp. 1137-1144 ◽  
Author(s):  
Aleš Ptáček ◽  
Jiří Kulič
Keyword(s):  
Alkaline Hydrolysis ◽  
Reaction Rate ◽  
Ion Concentration ◽  
Molar Ratio ◽  
Hexadecyltrimethylammonium Bromide ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Naphthoic Acid ◽  
Iodosobenzoic Acid ◽  
Hydrolysis Of

The hydrolysis of diphenyl (4-nitrophenyl) phosphate catalyzed by 2-iodosobenzoic and 3-iodoso-2-naphthoic acids has been studied at different pH values in the presence of hexadecyltrimethylammonium bromide as a micellar agent. It was found that 3-iodoso-2-naphthoic acid is better catalyst than 2-iodosobenzoic acid. At amounts of the acids higher than stoichiometric, the reaction is independent of pH in the 8.00 to 10.00 region while on using substoichiometric amounts, the reaction rate depends on OH- ion concentration only when the acid to diphenyl (4-nitrophenyl) phosphate molar ratio amounts to 12.5 : 1 for 2-iodosobenzoic acid and 6.25 : 1 for 3-iodoso-2-naphthoic acid.

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