The Orton rearrangement in aprotic solvents. Part IV. An examination of the kinetics of the rearrangement of N-bromo-4-chloroacetanilide and N-bromoacetanilide catalyzed by trifluoroacetic acid and trifluoroacetic acid-d

1981 ◽  
Vol 59 (5) ◽  
pp. 839-850 ◽  
Author(s):  
Peter David Golding ◽  
Sethu Reddy ◽  
John Marshall William Scott ◽  
Valerie Ann White ◽  
June Gertrude Winter
Keyword(s):  
Acid Concentration ◽  
Trifluoroacetic Acid ◽  
Trichloroacetic Acid ◽  
Comprehensive Analysis ◽  
Aprotic Solvents ◽  
Rate Law ◽  
Past Work ◽  
Kinetics Of

The rates of rearrangement of N-bromo-4-chloroacetanilide to 2-bromo-4-chloroacetanilide catalyzed by trifluoroacetic acid and trifluoroacetic acid-d have been measured as a function of acid concentration in chlorobenzene at T = 323 K. Similar experiments have been carried out with N-bromoacetanilide and N-bromo-4-chloro-2,6-dideuterioacetanilide. A comprehensive analysis of the observed rates for each substrate as a function of acid concentration reveals that the rearrangements involve at least three mechanistic steps when trifluoroacetic acid is the catalyst. In contrast, the rate of rearrangement of N-bromoacetanilide catalyzed by trichloroacetic acid at T = 288 K appears to follow a limiting form of the same rate law. Earlier observations are assessed in the light of the proposed mechanism, and it is concluded that both present and past work can be satisfactorily rationalized in terms of an intramolecular migration of bromine.

Kinetics of the addition of acids to olefins with and without boron fluoride catalysis

1967 ◽  
Vol 45 (1) ◽  
pp. 11-16 ◽  
Author(s):  
G. A. Latrèmouille ◽  
A. M. Eastham
Keyword(s):  
Activation Energy ◽  
Acetic Acid ◽  
Apparent Activation Energy ◽  
Trifluoroacetic Acid ◽  
Similar Rate ◽  
Ethylene Dichloride ◽  
Kcal Mole ◽  
Rate Law ◽  
Boron Fluoride ◽  
Kinetics Of

Isobutene reacts readily with excess trifluoroacetic acid in ethylene dichloride solution at ordinary temperatures to give t-butyl trifluoroacetate. The rate of the reaction is given, within the range of the experiments, by the expression d[ester]/dt = k[acid]2[olefin], and the apparent activation energy is about 6 kcal/mole. The rate of addition is markedly dependent on the strength of the reacting acid and is drastically reduced in the presence of mildly basic materials, such as dioxane. The boron fluoride catalyzed addition of acetic acid to 2-butene can be considered to follow a similar rate law, i.e. d[ester]/dt = k[acid·BF3]2[olefin], but only if some assumptions are made about the position of the equilibrium [Formula: see text]since only the 1:1 complex is reactive.

Solvent effects on the decarboxylation of trichloroacetic acid: insights from ab initio molecular dynamics simulations

2018 ◽  
Vol 20 (34) ◽  
pp. 21988-21998 ◽  
Author(s):  
Guilherme C. Q. da Silva ◽  
Thiago M. Cardozo ◽  
Giovanni W. Amarante ◽  
Charlles R. A. Abreu ◽  
Bruno A. C. Horta
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Solvent Effects ◽  
Trichloroacetic Acid ◽  
Ab Initio Molecular Dynamics ◽  
Aprotic Solvents ◽  
Protic Solvents ◽  
Dynamics Simulations ◽  
Kinetics Of

The kinetics of trichloroacetic acid (TCA) decarboxylation strongly depends on the solvent in which it occurs, proceeding faster in polar aprotic solvents compared to protic solvents.

Histometric and Histochemical Analysis of the Effect of Trichloroacetic Acid Concentration in the Chemical Reconstruction of Skin Scars Method

2006 ◽  
Vol 32 (10) ◽  
pp. 1231-1236
Author(s):  
SUNG BIN CHO ◽  
CHANG OOK PARK ◽  
WOO GIL CHUNG ◽  
KWANG HOON LEE ◽  
JUNG BOCK LEE ◽  
...  
Keyword(s):  
Acid Concentration ◽  
Trichloroacetic Acid ◽  
Histochemical Analysis

Ferricyanide Oxidation of Butanol Homogeneously Catalysed by Chlororuthenium Complexes

1979 ◽  
Vol 32 (9) ◽  
pp. 1905 ◽  
Author(s):  
AF Godfrey ◽  
JK Beattie
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Linear Dependence ◽  
Rate Constants ◽  
Homogeneous Catalyst ◽  
Basic Solution ◽  
Rate Law ◽  
Kinetics Of ◽  
Solution Estimates ◽  
Butanol Concentration

The oxidation of butan-1-ol by ferricyanide ion in alkaline aqueous solution is catalysed by solutions of ruthenium trichloride hydrate. The kinetics of the reaction has been reinvestigated and the data are consistent with the rate law -d[FeIII]/dt = [Ru](2k1k2 [BuOH] [FeIII])/(2k1 [BuOH]+k2 [FeIII]) This rate law is interpreted by a mechanism involving oxidation of butanol by the catalyst (k1) followed by reoxidation of the catalyst by ferricyanide (k2). The non-linear dependence of the rate on the butanol concentration is ascribed to the rate-determining, butanol-independent reoxidation of the catalyst, rather than to the saturation of complex formation between butanol and the catalyst as previously claimed. Absolute values of the rate constants could not be determined, because some of the ruthenium precipitates from basic solution. With K3RuCl6 as the source of a homogeneous catalyst solution, estimates were obtained at 30�0�C of k1 = 191. mol-1 s-1 and k2 = 1�4 × 103 l. mol-1 s-1.

Leaching kinetics of copper and valuable metal extraction from copper-cadmium residues of zinc hydrometallurgy by oxidation acid leaching

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jihao Guo ◽  
Hongao Xu ◽  
Bo Li ◽  
Yonggang Wei ◽  
Hua Wang
Keyword(s):  
Hydrogen Peroxide ◽  
Acid Concentration ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Agitation Rate ◽  
Leaching Kinetics ◽  
Solid Ratio ◽  
Zinc Hydrometallurgy ◽  
Kinetics Of ◽  
Leaching Efficiency

Abstract Multiple purification of zinc sulfate solution is an important process for zinc hydrometallurgy, and large quantities of copper-cadmium residues are generated as byproducts in this process. Copper-cadmium residues contain a large number of valuable metals that must be recovered. A comprehensive extraction process has been proposed using sulfuric acid as the leaching reagent and hydrogen peroxide as the oxidizing reagent. The effects of acid concentration, leaching temperature, leaching time, liquid-to-solid ratio, hydrogen peroxide dosage and stirring speed on the leaching efficiency were investigated. The optimum conditions were determined as an acid concentration of 150 g/L, liquid-to-solid ratio of 4:1, hydrogen peroxide amount of 20 mL, time of 60 min, temperature of 30 °C, particle size of −d75 μm, and agitation rate of 300 r/min. It was concluded that the leaching efficiency of copper and cadmium reached 97%, but because of the existence of zinc sulfide in the residues, a lower leaching efficiency of zinc was obtained. Furthermore, the leaching kinetics of copper was also studied based on the shrinking core model. The activation energy for copper leaching was 5.06 kJ/mol, and the leaching process was controlled by the diffusion through the product layer.

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