Kinetics of a Polyacid-Epoxy Condensation Reaction

1970 ◽  
Vol 3 (2) ◽  
pp. 202-206 ◽  
Author(s):  
J. Fellers
Keyword(s):  
Condensation Reaction ◽  
Kinetics Of

Liquid-phase aldol condensation of cyclohexanone on aluminium and iron oxides

1982 ◽  
Vol 47 (8) ◽  
pp. 2235-2245 ◽  
Author(s):  
Zdeněk Vít ◽  
Lubomír Nondek ◽  
Jaroslav Málek
Keyword(s):  
Iron Oxides ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Complex Function ◽  
Acid Sites ◽  
Basic Site ◽  
Catalyst Poisoning ◽  
Iron Hydroxides ◽  
Transient Complex ◽  
Kinetics Of

The kinetics of the aldol condensation of cyclohexanone in decalin were investigated at 210 °C on catalysts prepared by drying and calcining the aluminium and iron hydroxides at 110-850 °C. The effect of catalyst poisoning by benzoic acid and pyridine on the course of the condensation reaction and aldol retroaldolisation was also examined. The kinetics of the cyclohexanone condensation can be described by means of Langmuir-Hinshelwood equations which are in agreement with a mechanism involving adsorption of cyclohexanone on a basic site to form a transient complex, reaction of this complex with a cyclohexanone molecule affording the aldol, the rate determining interaction of the aldol with free basic and acid sites yielding 2-(1-cyclohexen-1-yl)cyclohexanone and water and desorption of these products from the catalyst surface. The proposed kinetic model is supported by the results of catalyst poisoning. The activity of aluminium and iron oxides in the condensation of cyclohexanone is a complex function of their basicity and acidity depending strongly on the calcination temperature.

scholarly journals Synthesis, Characterization and Kinetic Study of Monomeric Complexes of Cyclohexane-1, 2- bis (Thiosemicarbazone) with Cobalt (II), Nickel (II) and Copper (II)

2018 ◽  
Vol 28 (2) ◽  
pp. 48
Author(s):  
Al-Ameen Bariz Omar Ali
Keyword(s):  
Metal Complexes ◽  
Kinetic Study ◽  
General Formula ◽  
Metal Salt ◽  
Condensation Reaction ◽  
Coordination Complex ◽  
Stopped Flow ◽  
Order Dependence ◽  
Kinetics Of

Cyclohexane-1,2-bis(thiosemicarbazone) (CHTSC) was synthesized via the condensation reaction of cyclohexane-1,2-dione and thiosemicarbazide. Series of metal complexes of the prepared lig-and, of general formula [M(CHTSC)(NO3)2], were reported. The prepared coordination complex-es were characterized and their structures elucidated using different techniques. These showed that all complexes are octahedral geometries. The kinetics of the formation of these complexes have been investigated using stopped-flow spectrophotometry. These studies revealed that the reactions are completed on the second’s timescale with 1st-order dependence (either on the con-centration of metal salt or on the concentration of CHTSC).

The Mechanism and Kinetics of Intramolecular Condensation Reaction of 1,3-Diaryl-3-(2-amino-phenylsulfenyl)-propan-1-one

1998 ◽  
Vol 14 (11) ◽  
pp. 1048-1052
Author(s):  
Li Yuan ◽  
◽  
Huang Bao-Hua ◽  
Lv Ying-Chao ◽  
Jin Sheng ◽  
...  
Keyword(s):  
Condensation Reaction ◽  
Intramolecular Condensation ◽  
Mechanism And Kinetics ◽  
Kinetics Of

Kinetics of glycoluril template-directed Claisen condensations and mechanistic implications

2002 ◽  
Vol 80 (5) ◽  
pp. 517-527 ◽  
Author(s):  
Mohammad Rahimizadeh ◽  
Karen Kam ◽  
Stephen I Jenkins ◽  
Robert S McDonald ◽  
Paul HM Harrison
Keyword(s):  
Uv Spectroscopy ◽  
Condensation Reaction ◽  
Order Rate Constant ◽  
Nucleophilic Attack ◽  
First Order ◽  
Order Rate ◽  
First Order Kinetics ◽  
Benzoyl Group ◽  
Excess Base ◽  
Kinetics Of

Eight N-acetyl-N-aroyl-glycolurils were prepared and found to undergo efficient tert-butoxide-promoted Claisen-like condensation between the two acyl moieties. The kinetics for formation of each of the N-(aroylacetyl)gly coluril products were monitored by UV spectroscopy. The reaction exhibited pseudo-first-order kinetics in substrate in the presence of excess base. For the parent benzoyl compound the observed first-order rate constant (kobs) was linearly dependent on the concentration of the base, tert-butoxide. A Hammett plot of the resulting apparent second-order rate constants (kapp) vs. σ for each of the eight aroyl derivatives was linear and had a positive ρ value 1.04 ± 0.04), demonstrating that the substituent on the aromatic ring exerts a significant effect upon the condensation reaction. The corresponding plot for three [D3]acetyl analogues was also linear, but the slope was reduced by 20% relative to the protonated compounds. The isotope effect (kHapp/kDapp) thus increased from 1.4 (benzoyl) to 2.6 (p-nitrobenzoyl). The results are consistent with a three-step mechanism in which both deprotonation of the acetyl entity and the ensuing nucleophilic attack of the resulting enolate on the benzoyl group are partially rate-determining steps. The tetrahedral intermediate thus produced rapidly collapses to the product. For the [D3]acetyl benzoyl derivative, exchange of substrate deuterium with solvent hydrogen due to reprotonation of the enolate intermediate occurs at a rate that is similar to that of condensation, but the enolate partitions towards the product when electron withdrawing groups are present in the aroyl ring. Thus, despite the presence of a large excess of co-solvent tert-butanol, the efficiency with which the enolate undergoes condensation remains high. The clean kinetics observed allows further exploration of the details of this intramolecular Claisen-like condensation process.Key words: Claisen condensation, glycoluril, kinetics, Hammett, mechanism.

scholarly journals The Kinetics of the Gas Phase Aldol Condensation Reaction of Propionic Acid with Formaldehyde on B2O3-P2O5-WO3/SiO2 Catalyst

2014 ◽  
Vol 8 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Roman Nebesnyi ◽  
◽  
Volodymyr Ivasiv ◽  
Zorian Pikh ◽  
Viacheslav Zhyznevskyi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Propionic Acid ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Kinetics Of

Lignin Utilization I. Kinetics of Base-Catalyzed Condensation Reactions of Lignin Model Compounds

1972 ◽  
Vol 2 (3) ◽  
pp. 271-275 ◽  
Author(s):  
G. E. Troughton ◽  
J. F. Manville
Keyword(s):  
Condensation Reaction ◽  
Activation Energies ◽  
The Self ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Temperature Range ◽  
Condensation Reactions ◽  
Lignin Model ◽  
Lignin Utilization ◽  
Kinetics Of

Rates of formation were measured for the base-catalyzed condensation reactions occurring between 4-alkylguaiacol compounds and their 6-methylol derivatives over the temperature range 85.5–100 °C. It was found that both the intercondensation reaction between the 4-alkylguaiacol compound and its 6-methylol derivative and the self-condensation reaction of the latter compound occurred at significant rates. In the 4-propylguaiacol – 4-methyl-6-methylolguaiacol system, the above two condensation reactions occurring in this system had the same activation energies, 35 kcal/mol. Similarly, in the 4-methylguaiacol – 4-propyl-6-methylolguaiacol system these two condensation reactions had equivalent activation energies, but slightly lower than in the former system, 32 kcal/mol. The kinetic results found for the model guaiacol compounds in this study demonstrate the possibility that a lignin-derived compound having more than one reactive position can be developed into a phenolic-type resin.

A study on the kinetics of condensation reaction of cardanol and formaldehyde, part I

2009 ◽  
Vol 41 (9) ◽  
pp. 559-572 ◽  
Author(s):  
Minakshi Sultania ◽  
J. S. P. Rai ◽  
Deepak Srivastava
Keyword(s):  
Condensation Reaction ◽  
Kinetics Of
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