The transmission of polar effects. Part V. The kinetics of esterification with diazodiphenylmethane and the ionization of substituted acetic and propionic acids in several solvents

1968 ◽  
Vol 46 (18) ◽  
pp. 2929-2940 ◽  
Author(s):  
Keith Bowden ◽  
M. Hardy ◽  
D. C. Parkin
Keyword(s):  
Isopropyl Alcohol ◽  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Esterification Reaction ◽  
Linear Free Energy ◽  
Ionization Reaction ◽  
Reaction Constants ◽  
Polar Substituents ◽  
Energy Relations ◽  
Kinetics Of

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol,t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, dimethyl sulfoxide, ethyl acetate, and toluene at 30° and the pKa values in water, 50% ethanol–water, and 80% 2-methoxyethanol–water of 18 substituted acetic and propionic acids have been determined. A further 14 acids have been studied to a more limited extent. The effect of substitution has been estimated by linear free energy relations. The reaction constants for the ionization reaction are almost independent of the medium. This is interpreted as being due to the field effect of the proximate polar substituents passing through the molecular cavity almost alone. The occurrence of steric inhibition of solvation causing acid weakening for bulky multi-substitution is confirmed. The reaction constants for the esterification reaction are affected by the solvent. This is attributed to dependence on solvation of the transition state.

THE TRANSMISSION OF POLAR EFFECTS: PART II. THE KINETICS OF ESTERIFICATION WITH DIAZODIPHENYLMETHANE AND THE IONIZATION OF 3-SUBSTITUTED ACRYLIC ACIDS

1965 ◽  
Vol 43 (12) ◽  
pp. 3354-3363 ◽  
Author(s):  
Keith Bowden
Keyword(s):  
Butyl Alcohol ◽  
Polar Effect ◽  
Rate Coefficients ◽  
Strengthening Effect ◽  
Benzoic Acids ◽  
Linear Free Energy ◽  
Substituted Benzoic Acids ◽  
Energy Relations ◽  
Acrylic Acids ◽  
Kinetics Of

The rate coefficients for the reaction with diazodiphenylmethane in ethanol, t-butyl alcohol, and ethyl acetate at 30° and the pKa values in water at 25° of fourteen 3-substituted acrylic acids have been determined. The effect of substitution is assessed by use of linear free energy relations. A definite incremental acid-strengthening effect solely due to cis-substitution is confirmed. This is not a "bulk" steric effect and is due solely to the orientation of substitution. The polar effect of a substituent is found to be approximately the same from the cis- or trans-position. An attempt is made to test the suggested mechanisms for the transmission of the polar effect. In the reactions studied the transmission of the polar effect in 3-substituted acrylic acid and ortho-substituted benzoic acids is approximately twice that of the meta- or para-substituted benzoic acids. This appears to be reasonably accommodated by a significant field effect.

The transmission of polar effects. Part X. The esterification with diazodiphenyl-methane and the ionization of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids

1969 ◽  
Vol 47 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Keith Bowden ◽  
D. C. Parkin
Keyword(s):  
Free Energy ◽  
Ethyl Acetate ◽  
Field Effect ◽  
Isopropyl Alcohol ◽  
Substituent Effects ◽  
Butyl Alcohol ◽  
Rate Coefficients ◽  
Linear Free Energy ◽  
Energy Relations ◽  
Substituted 1

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol, t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, and ethyl acetate at 30° and the pKa values in 80% 2-n-butoxyethanol–water of a series of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids have been determined. The effect of substitution has been analyzed by linear free energy relations. The variation in the susceptibilities of the systems to polar substituent effects with the medium are examined. The occurrence of reversed dipolar substituent effects in the reactions of the 1,8-naphthoic acids is detected. The implications of the results for the inductive and field effect models for the transmission of polar effects are discussed.

scholarly journals Transmission of dipolar substituent effects: ionization of a series 3-(7-substituted-1-naphthyl) propynoic acid (E)-3-(7-substituted-1-naphthyl) propenoic acids and their Esterification with Diazodiphenylmethane

2021 ◽  
Vol 05 (02) ◽  
pp. 1-9
Author(s):  
Ghadir Khalaf ◽  
Sameerah Mustafa ◽  
Ghaidaa Kadhim ◽  
Hadeel Hasan
Keyword(s):  
Alkaline Hydrolysis ◽  
Steric Effect ◽  
Substituent Effects ◽  
Rate Coefficients ◽  
Esterification Reaction ◽  
Ionization Reaction ◽  
Result Show ◽  
Esterification Rate ◽  
Propynoic Acid ◽  
Substituted 1

Alkaline hydrolysis rates coefficients for the series of methyl 3-(7-substituted-1-naphthyl) propynoate was calculated in 70%v/v dimethylsulphoxide-water at various temperatures (25,30,40, and 50̊ C). The pKa values of 3-(7-substituted-1-naphthyl) propynoic acid and (E)- 3-(7-substituted-1-naphthyl) propenoic acid calculated in 80%w/w 2-methoxyethanol-water at room temperature (25.0̊ C). logk2 of esterification rate coefficients for 3-(7-substituted-1-naphthyl) propynioc acid and (E)-3(7-substituted-1-naphthyl) propenioc acid with DDM have been measured at 30.0̊ C. Reversed substituent dipolar effects were found in the ionization reaction. In the esterification reaction with DDM the result show similar but reduced substituted effects. Rate retardations was found in the alkaline hydrolysis. It could be result from steric effect or reversal of substituent dipolar effect with a combination of steric effect.

scholarly journals The Kinetics of Calcium Oxide Catalyzed Esterification of Glycerol with Free Fatty Acids Using Pseudo-homogeneous Model Approach

REAKTOR ◽  
2018 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Megawati Megawati ◽  
Dhoni Hartanto ◽  
Catur Rini Widyastuti ◽  
Diyah Saras Wati ◽  
Eny Nurhayati
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Reaction Kinetics ◽  
Calcium Oxide ◽  
Homogeneous Model ◽  
Solid Catalyst ◽  
Esterification Reaction ◽  
Oxide Content ◽  
Reaction Constants ◽  
Kinetics Of

Abstract This research aims to study the reaction kinetics of esterification reaction of glycerol with free fatty acid (FFA) using calcium oxide catalyst to produce mono-diacylglycerol (MDAG) using pseudo-homogeneous approach. The effects of time and temperature on the reaction conversion were investigated simultaneously. The FFA used was from the waste of cocoa production process, while the solid catalyst used was calcium oxide from eggshell ash. The results show that the cocoa based FFA was composed of palmitic acid (49.24%), methyl stearate (1.05%), oleic acid (25.39%), and stearic acid (24.32%). The calcium oxide content in the eggshell ash was 60% w/w. At all temperatures studied (60, 70, and 80oC), as the reaction time increased, the conversion increased sharply in the first 5 minute followed by a gradual raise to an almost constant value after 20 minutes (0.844; 0.845; and 0.854, respectively). Pseudo-homogeneous second order model can describe the reaction kinetics satisfactorily. The reaction constants (k) at 60, 70, and 80oC were 0.00384, 0.003401, and 0.003518 (L/mole.minute), respectively. The effects of temperature on reaction rate obey the Arrhenius’ equation with collision factor (A) is 0.2659 (L/mole.minute) and activation energy (Ea) is 3544 J/mol. Keywords: calcium oxide; free fatty acid; glycerol; pseudo-homogeneous approach

The transmission of polar effects. Part IX. The ionization and esterification with diazodiphenylmethane of 9-substituted 10-triptoic acids

1969 ◽  
Vol 47 (2) ◽  
pp. 177-183 ◽  
Author(s):  
Keith Bowden ◽  
D. C. Parkin
Keyword(s):  
Free Energy ◽  
Field Effect ◽  
Inductive Effect ◽  
Rate Coefficients ◽  
Linear Free Energy ◽  
Effect Model ◽  
Energy Relations

A series of 9-substituted 10-triptoic acids have been prepared. Their pKa values in 80% 2-methoxy-ethanol–water and 50% ethanol–water at 25° and rate coefficients for esterification with diazodiphenyl-methane in five alcohols at 30° have been measured. The results have been analyzed by linear free energy relations. The π-inductive effect is shown to be unimportant in such systems, while the field effect model can account for the transmission.

Influence of solvent on kinetics of reactions of Cr(II) ions

1981 ◽  
Vol 46 (7) ◽  
pp. 1554-1559 ◽  
Author(s):  
Peter Ševčík ◽  
Ján Tkáč
Keyword(s):  
Mole Fraction ◽  
Methyl Alcohol ◽  
Maleic Acid ◽  
Redox Reaction ◽  
Isopropyl Alcohol ◽  
Butyl Alcohol ◽  
Dichloroacetic Acid ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Kinetics Of

This paper deals with the study of redox reactions of Cr(II) ions with hydroxylamine, hydrazoic acid, maleic acid, di- and trichloroacetic acids in so-called typically aqueous mixtures of water with methyl alcohol, isopropyl alcohol, or tert-butyl alcohol. The kinetics of the redox reaction with dichloroacetic acid was studied also in the medium of aqueous acetone and in a typically nonaqueous medium water-acetonitrile. The dependences of activation Gibbs energies on the mole fraction of the nonaqueous component have no minima and maxima characteristic for the thermodynamic behaviour of the mentioned binary systems. However, the change of the activation Gibbs energy with the mole fraction of tert-butyl alcohol is not monotonous with all the studied reactions of Cr(II) ions. At a constant mole fraction of the nonaqueous component, the usual trend of the influence on the rate constants decreases in the sequence tert-butyl alcohol > isopropyl alcohol > methyl alcohol. Tert-butyl alcohol hinders most strongly the redox reaction with trichloroacetic acid, whereas it accelerates the reaction of Cr(II) ions with maleic acid and hydroxylamine.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

Solubility and Thermodynamic Transfer Functions of Cesium Dianilinetetraisothiocyanatochromate(III)

1998 ◽  
Vol 63 (3) ◽  
pp. 293-298
Author(s):  
Vladislav Holba
Keyword(s):  
Experimental Data ◽  
Isopropyl Alcohol ◽  
Transfer Functions ◽  
Butyl Alcohol ◽  
Aqueous Methanol ◽  
Gibbs Energies ◽  
Gibbs Energy Of Transfer ◽  
Energy Of Transfer ◽  
The Given ◽  
Reference Electrolyte

The solubilities of cesium dianilinetetraisothiocyanatochromate(III) in water as well as in aqueous methanol, isopropyl alcohol, tert-butyl alcohol and acetonitrile were measured as a function of temperature and solvent composition. The Gibbs energies, enthalpies and entropies of transfer of the salt from water to the given solvents have been evaluated from experimental data. The contribution of [Cr(C6H5NH2)2(NCS)4]- ion to the Gibbs energy of transfer of the investigated salt has been calculated using the tetraphenylarsonium tetraphenylborate (TATB) reference electrolyte assumption.

The Formation of Cu3Si from Cu/a-Si Multilayers

1997 ◽  
Vol 481 ◽  
Author(s):  
R. R. Chromik ◽  
W. K. Neils ◽  
E. J. Cotts
Keyword(s):  
Diffusion Couples ◽  
X Ray Diffraction ◽  
Limited Growth ◽  
Scanning Calorimetry ◽  
Individual Layer ◽  
Diffusion Limited ◽  
Reaction Constant ◽  
Multilayered Composites ◽  
Reaction Constants ◽  
Kinetics Of

ABSTRACTThe kinetics of the formation of Cu3Si in Cu/a-Si diffusion couples have been investigated by means of differential scanning calorimetry and x-ray diffraction. Multilayered composites of average stoichiometry Cu3Si were prepared by sputter deposition with individual layer thicknesses varying in different samples between 2 and 100 nm. We observed diffusion limited growth of Cu3 Si upon annealing these diffusion couples below 500 K. Reaction constants were measured for a temperature range of 455 to 495 K for thicknesses of growing Cu3Si between 2.6 and 80 nm. The temperature dependence of the reaction constant, k2, was characterized as k2 = k0 exp(− Ea/kbT) with activation energy, Ea = 1.0 eV/atom and pre-factor, k0 = 1.9×10−3 cm2/s.

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