Solvent and Acidity Function Effects in the Kinetics of the Acid Hydrolysis of Ditert-Butylsuccinate in Aqueous Acetone

1991 ◽  
Vol 95 (7) ◽  
pp. 778-781
Author(s):  
M. T. Hanna ◽  
Fayez Y. Khalil ◽  
Adel N. Asaad
Keyword(s):  
Acid Hydrolysis ◽  
Aqueous Acetone ◽  
Acidity Function ◽  
Kinetics Of ◽  
Hydrolysis Of

scholarly journals Kinetics of the Acid Hydrolysis of Substituted Benzoic Anhydrides in Dioxan-Water Mixtures.

1964 ◽  
Vol 18 ◽  
pp. 2248-2254 ◽  
Author(s):  
J. Koskikallio ◽  
A. Holm ◽  
Nils Andreas Sørensen ◽  
D. R. Sparrow
Keyword(s):  
Acid Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of

Evidence for the formation of lignin-hexenuronic acid-xylan complexes during modified kraft pulping processes

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Zhi-Hua Jiang ◽  
Jean Bouchard ◽  
Richard Berry
Keyword(s):  
Acid Hydrolysis ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Order Kinetic ◽  
Kraft Pulps ◽  
First Order ◽  
Pseudo First Order ◽  
Hexenuronic Acid ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The finding that hexenuronic acid (HexA) groups can be selectively removed from kraft pulps by acid hydrolysis has provided an opportunity to reduce bleaching chemicals. However, there is evidence that the acid hydrolysis is not uniform. In this report, we evaluate the kinetics of acid hydrolysis of HexA in a xylan sample enriched with HexA, a conventional kraft pulp, and three modified kraft pulps: anthraquinone pulp (Kraft-AQ), polysulfide pulp (PS), and polysulfide-anthraquinone pulp (PS-AQ). We found that HexA present in the xylan and conventional kraft pulp behaved similarly toward the acid hydrolysis throughout. On the other hand, HexA present in the Kraft-AQ, PS-AQ and PS pulps was heterogeneous toward acid hydrolysis and the reaction can be separated into two pseudo-first-order kinetic phases, each of which has a different rate constant. The kinetic data provide evidence for the formation of lignin-HexA-xylan complexes during modified kraft pulping processes.

THE ACID HYDROLYSIS OF GLYCOSIDES: I. GENERAL CONDITIONS AND THE EFFECT OF THE NATURE OF THE AGLYCONE

1964 ◽  
Vol 42 (6) ◽  
pp. 1456-1472 ◽  
Author(s):  
T. E. Timell
Keyword(s):  
Acid Hydrolysis ◽  
Equilibrium Concentration ◽  
Rate Coefficients ◽  
Acidity Function ◽  
Tertiary Alcohols ◽  
Conjugate Acid ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Opposing Effects ◽  
Hydrolysis Of

First-order rate coefficients and energies and entropies of activation have been determined for the acid-catalyzed hydrolysis of a number of methyl D-glycopyranosides and disaccharides. The relation between the logarithm of the rate coefficients and values for Hammett's acidity function was linear, although different for different acids. All compounds had entropies of activation indicating a unimolecular reaction mechanism. Glucosides of tertiary alcohols were hydrolyzed very rapidly, triethylmethyl β-D-glucopyranoside, for example, 30,000 times taster than the corresponding methyl compound.Increase in size of the aglycone caused a slight increase in the rate of hydrolysis of β-D-glucopyranosides, steric hindrance thus being of no significance. Electron-attracting substituents in the aglycone had little or no influence on the rate of hydrolysis, obviously because they would tend to lower the equilibrium concentration of the conjugate acid, while facilitating the subsequent heterolysis, the two opposing effects more or less cancelling out. These results were discussed in connection with recent studies on the acid hydrolysis of various phenyl glycopyranosides and with reference to the postulated occurrence of an activating inductive effect in oligo- and poly-saccharides containing carboxyl or other electronegative groups at C-5. It was concluded that there is little evidence for the existence of any such effect and that, for example, pseudoaldobiouronic acids should be hydrolyzed at the same rate as corresponding neutral disaccharides.

scholarly journals Acid Hydrolysis of Bromazepam Catalyzed by Micelles, Reverse Micelles, and Microemulsions

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Ferdousi Begum ◽  
M. Yousuf A. Mollah ◽  
M. Muhibur Rahman ◽  
Md. Abu Bin Hasan Susan
Keyword(s):  
Physicochemical Properties ◽  
Acid Hydrolysis ◽  
Reverse Micelles ◽  
Cetyltrimethylammonium Bromide ◽  
Order Rate Constant ◽  
Excellent Correlation ◽  
Initial Decrease ◽  
Droplet Sizes ◽  
Kinetics Of ◽  
Hydrolysis Of

Kinetics of the acid hydrolysis of bromazepam (Bz) has been investigated in micelles, reverse micelles, and microemulcions of cetyltrimethylammonium bromide (CTAB) by spectrophotometric method. The rate of the acid hydrolysis of Bz was found to be enhanced both below and above the critical micelle concentration (CMC) of CTAB in aqueous solution. The pseudo-first-order rate constant (k′) shows an initial decrease for both low and high H+concentrations. With further increase in [CTAB], at low [H+], thek′attains an almost constant value, while, at high [H+], thek′passes through a maximum and then decreases. The kinetic data for catalysis by micelles of CTAB was interpreted with the pseudophase ion exchange (PIE) model. In CTAB/cyclohexane/1-butanol/water microemulsions, as the water to surfactant ratio (wo) increases, the physicochemical properties and droplet sizes of microemulsions significantly change and distinct changes in reaction environment can be marked. The rate of the hydrolysis reaction exhibits excellent correlation with the physicochemical properties and droplet sizes of the microemulsions and reverse micelles of CTAB. At [H+] = 0.001 M, in reverse micelles and microemulsions of CTAB, thek′of the acid hydrolysis of Bz decreases sharply followed by a slight increase with increasingwo.

Evaluation of the Kinetics of Xylose Formation from Dilute Sulfuric Acid Hydrolysis of Forest Residues ofEucalyptusgrandis

2007 ◽  
Vol 46 (7) ◽  
pp. 1938-1944 ◽  
Author(s):  
Eliana V. Canettieri ◽  
George J. M. Rocha ◽  
João A. Carvalho, ◽  
João B. A. Silva
Keyword(s):  
Sulfuric Acid ◽  
Acid Hydrolysis ◽  
Forest Residues ◽  
Dilute Sulfuric Acid ◽  
Kinetics Of ◽  
Hydrolysis Of

Synthesis and kinetics of the acid hydrolysis of the monothiooxalato-S,O-bis(ethylenediamine)chromium(III) complex

Polyhedron ◽  
1995 ◽  
Vol 14 (23-24) ◽  
pp. 3611-3616 ◽  
Author(s):  
Zhong Chen ◽  
Yi-Jian Zhang ◽  
Yang Gung ◽  
Yifan Wu ◽  
Ruhullah Massoudi
Keyword(s):  
Acid Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of
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