S V Anantakrishnan
Articles written in Proceedings – Section A
Volume 12 Issue 3 September 1940 pp 290-305
The kinetics of the olefin-bromine reaction has been studied in acetic acid solution using three related aliphatic monobasic acids. The course of the reaction clearly indicates a chain mechanism. It is found that the reaction is of the first order with respect to the olefin and the influence of the catalyst hydrogen bromide is pronounced, the experimental evidence favouring a complex formation between olefin and catalyst.
Volume 12 Issue 3 September 1940 pp 306-311
The dark reaction, catalysed and uncatalysed, between methyl substituted acrylic acids and bromine has been investigated at 25°C., 35°C., 42°C., and 50°C. in glacial acetic acid solution. An analysis of the critical increment shows not only group influence but also an orientation effect.
Volume 13 Issue 3 March 1941 pp 211-220
The nitration of fluoryl-9-trimethylammonium compounds and the orientation of the products is described. It has been found that the best method of obtaining the unsubstituted ‘Onium salt is from 9-bromofluorene. The 9-substituent does not appear to have any marked influence on the position of new entrant groups but exerts a noticeable one on the activity of the nuclear positions. The converse influence of nuclear substituents on the activity of the 9-position is evident.
Volume 14 Issue 3 September 1941 pp 270-278
The kinetics of acid hydrolysis of some aliphatic esters have been studied at four different temperatures in 60% dioxan. The effect of the halogen on the parameters of the Arrhenius equation have been discussed from the standpoint of the electronic theory of organic reactions.
Volume 14 Issue 3 September 1941 pp 279-288
The kinetics of acid hydrolysis of ethyl acetate, ethyl propionate and ethyl chloracetate in glycerol-water system has been studied. Both viscosity and dielectric constant influence the reaction and a close correlation of the parameters of the reaction velocity equation is noticed.
Volume 14 Issue 6 December 1941 pp 609-615
The constituents of the seeds of
The authors thank the Superintendent, Government Test House, Alipore, for an analysed sample of raw linseed oil that was used for comparison and standardisation of experimental conditions.
Volume 14 Issue 6 December 1941 pp 616-629
The oil from the seeds of
The sterol in the unsaponifiable matter is essentially sitosterol.
Volume 20 Issue 3 September 1944 pp 128-137
Volume 21 Issue 3 March 1945 pp 114-122
Using the method of Gray but with the values of ionic susceptibilities derived by Slater's method, bond depression values have been set up for various linkages. With these values, the molar susceptibility of a large number of compounds have been calculated and a close agreement between the calculated and observed values is obtained. An empirical correlation is found between bond-order and bond-depression and the results clearly indicate the double bonded character of certain carbon-carbon and carbon-halogen linkages. A method of evaluating ionic susceptibilities using ammonium and nitrate ions as standards is indicated.
Volume 23 Issue 6 June 1946 pp 307-311
A kinetic equation has been derived for a homogeneous catalysed reaction in which both the reactants of a bimolecular reaction are activated by the catalyst and the equation applied to the reaction between crotonic acid and bromine catalysed by hydrogen bromide. The variation of rate with change of catalyst is also indicated.
Volume 23 Issue 6 June 1946 pp 312-318
A study of the reaction between bromine and fumaric acid and bromine and stilbene brought out clearly the validity of the rate equation derived in the previous part. The uncatalysed addition reaction of fumaric acid exhibits the characteristics of a degenerate branching chain.
Volume 23 Issue 6 June 1946 pp 320-324
An analysis of the Arrhenius parameters for the addition reaction indicates that the reaction is a composite one and of the “slow” type. The influence of substituents on the energy of activation and on the frequency factor is discussed and the abnormal values of the latter are accounted for. A close correlation is also noticed between the two.
Volume 25 Issue 6 June 1947 pp 520-522
Calculation of magnetic susceptibility for the different valence bond structures indicate that ozone should be diamagnetic, the susceptibility being about −18×10−6 while reported experimental values show that it is feebly paramagnetic in the liquid state, diamagnetic values being reported for the gaseous state. The possible causes of the discrepancy and a comparison with oxygen are discussed. The magnetic behaviour may be considered to conform to what may be expected from other physical properties of ozone.
Volume 27 Issue 3 March 1948 pp 184-191
The influence of substituents on the additive reactivity is reconsidered with particular reference to the Arrhenius parameters. Using the correction terms for the frequency factor in order to account for correct orientation of reactants, the activation energy of ethylene and a number of ethylene derivatives have been calculated. The correlation with the bond stretching force constant and the grouping together of ethylene derivatives on the basis of mechanistic differences follows from these results. The mutual action of groups and the peroxide effect are briefly considered. The solvent affects essentially the activation energy of the rate determining step.
Volume 30 Issue 1 July 1949 pp 23-29
A linear relationship is observed between the square of the bond frequency and the activation energy in the case of a few reactions in which substituents in the para-position are changed. Earlier work on similar problems is discussed and some discrepancies accounted for.
Volume 32 Issue 1 July 1950 pp 52-63
Experimental data on different reactions commonly used in the study of organic compounds have been studied and the parameters of the reaction rate equation considered in relation to mechanism and the structure of the compounds. The limitations of these reactions and the relation of reactivity to the Arrhenius parametrs is also brought out.
Volume 32 Issue 2 August 1950 pp 85-94
The kinetics of the hydrolysis of ethyl acetate in acetone-water and dioxane-water systems are reported. The rate constant passes through a minimum when the concentration of the organic solvent in the medium is in the neighbourhood of 80%. The temperature variation conforms strictly to the Arrhenius equation even for media containing extremely high proportions of organic solvent. Even though the activation energy is affected by changes in solvent composition, the variations are not sufficiently marked for an analysis. The frequency factor has got a tendency to follow the trend of activation energies.
Volume 32 Issue 3 September 1950 pp 187-196
The alkaline hydrolysis of ethyl acetate in dioxane-water and acetonewater mixtures have been studied. The trend of the reaction rate shows a maximum in the region of 10% organic solvent except in the case of acetonewater mixtures at 30°C. A close parallelism is observed in the variations of both E and log10 PZ values in the two series of solvent mixtures. Also, the PZ values have a marked tendency to follow changes in energies of activation.
Volume 32 Issue 5 November 1950 pp 1- Erratum
Volume 32 Issue 5 November 1950 pp 330-337
The influence of solvent on the rates of acid catalysed and alkaline hydrolysis of ethyl acetate has been discussed, the main factor taken into consideration being dielectric constant of the medium. Considerable light has been thrown on the precise role of the water molecule in alkaline hydrolysis. Specific solvent effects are also clearly noticeable since the reaction velocities, for both acid and alkaline hydrolysis, are more sensitive to changes in dielectric constant in acetone-water than in dioxane-water mixtures.
Volume 32 Issue 6 December 1950 pp 1- Erratum
Volume 34 Issue 5 November 1951 pp 299-303
A consideration of the properties of the alkali alkyls shows clearly that the compounds are essentially salt-like in nature, the bond between the alkali ion and the alkide ions being ionic in character.
Volume 36 Issue 3 September 1952 pp 201-207
The data obtained in earlier work have been recalculated to give the rate constants under iso-dielectric conditions. These results clearly show that specific solvent effects are present in both acid and alkaline hydrolysis. There is a possible change in the polarisation of the ester molecule with composition in which structural changes in the liquid state presumably play a part.
Volume 36 Issue 4 October 1952 pp 299-305
The conditions for the estimation of nitrogen by the Kjeldahl method have been studied and the limitations examined. A tentative picture of the action of selenium in the reaction is also indicated.
Volume 37 Issue 4 April 1953 pp 578-583
The dipole moments of tetrahydropyran and dihydropyran have been obtained from measurements of dielectric constants of benzene solutions using a heterodyne beat method and following Hedestrand’s method of extrapolation for arriving at the value for total polarisation. The results obtained have been discussed in relation to the structure of these compounds.
Volume 37 Issue 6 June 1953 pp 747-751
Dipole moment measurements on
Volume 38 Issue 2 August 1953 pp 176-183
Measurements of dielectric constants and densities of solutions of different concentrations of furoin and hydrofuramide in benzene as also refractive index measurements for hydrofuramide, have been carried out and the dipole moments of the above substances calculated from values of ‘P’ arrived at by the application of the Hedestrand’s method of extrapolation. The values of dipole moments of the two substances are: Hydrofuramide=2·66±·01 D. Furoin 3·24 D. The structures of furoin and hydrofuramide have been discussed from the experimentally obtained values and those calculated for various positions of furyl groups in the latter and furyl and hydroxyl groups in the former by the method of vector addition of moments.
Volume 40 Issue 1 July 1954 pp 47-56
The reaction between trans-crotonic acid as well as 2 : 2-dimethyl acrylic acid and bromine has been studied in carbon tetrachloride solution in the dark. The reaction is found to be quite a complex one involving both homogeneous and heterogeneous phases. The course of the reaction is governed by the nature of the olefine and the nature of the catalysing surface.
Volume 40 Issue 2 August 1954 pp 91-95
Iodine bromide and chloride as well as pyridine have been used as catalysts for the reaction between bromine and crotonic and dimethyl acrylic acids. The reaction is quite complex and does not seem to conform to any simple rate equation. Even with the addition of the catalyst, the heterogeneous part of the reaction does not seem to be eliminated.
Volume 40 Issue 3 September 1954 pp 132-139
The reaction between pyridine and methyl iodide has been studied in 95 per cent. ethyl alcohol and in acetone. The reaction is faster in the latter solvent at the three temperatures studied. The Arrhenius parameters have been evaluated and the variations discussed in relation to solvent influences.
Volume 43 Issue 2 February 1956 pp 99-105
The dipole moments of 2-amino-1 ∶ 4-dimethoxy benzene and of 2-amino-1 ∶ 4-diethoxy benzene have been studied in benzene and in carbon tetrachloride solution. The values of the moments are discussed in relation to the moments of the unsubstituted parent carbon compounds. The interaction between three groups of similar characteristics is considered in relation to their steric effects.
Volume 49 Issue 2 February 1959 pp 86-95
The alkaline hydrolysis of ethyl acetate in water containing small additions of acetone have shown that the earlier expectations of abnormal trend in the rate of reaction were correct. The absence of mechanistic change is indicated by the continuity in the curve for correlation of the two Arrhenius parameters. Any explanation has to be in relation to the structure of the environment of the reacting species and the requirement of the properly hydrated reacting ion.
Volume 49 Issue 3 March 1959 pp 174-183
The kinetics of the hydrolysis of ethyl acetate by hydroxyl ions in dioxan-water systems also shows the same anticipated deviations from the Kirkwood picture of ion-dipole reactions. For small additions of organic solvents, more than the dielectric constant, the mole fraction of water and the changes in the environment of the transition state appear to be more significant. This is indicated by the reaction in the presence of acetate ions. The results are compared with those in acetone-water systems.
Volume 51 Issue 6 June 1960 pp 310-318
An analysis of the various factors affecting the oxidation of secondary alcohols by chromic acid in aqueous acetic acid systems shows the following features. The formation of an ester of chromic acid is not essential to oxidation. Both structural and solvent influences from the study of a series of secondary alcohols, aliphatic as well as aromatic, suggest that in the rate-determining step of the reaction the C-H hydrogen is removed as a hydride ion. The rate-determining step involves a two-electron transfer and the reacting species can be hexavalent and pentavalent chromium. A tentative mechanism of the reaction has been suggested incorporating these features.
Volume 53 Issue 1 January 1961 pp 28-34
The alkaline hydrolysis of some benzoic esters in dioxan-water mixtures as well as that of benzyl benzoate in acetone-water has been studied. The observations indicate a group influence consistent with the ease of formation of the transition state by interaction between the hydroxyl ion and the carbonyl group of the ester in the rate determining step. The influence of dielectric constant is what might be expected for an ion-dipole reaction but specific solvent influences cannot be excluded.
Volume 56 Issue 5 November 1962 pp 249-257
Kinetic studies in ester hydrolysis - Part XIII. The alkaline hydrolysis of benzene dicarboxylic esters and the half ester of succinic acid—A study of consecutive reactions and the mechanism of half ester hydrolysis
The study of hydrolyses of the diesters of benzene dicarboxylic acids as a consecutive reaction and of the sodium salt of the half ester in mixed solvents clearly indicates that both in the first and in the second stage the reaction is only of the ion-dipole type. Calculations of the dimensions of the reactant species show that the most reasonable values are given by the Laidler approach while the Ingold calculations probably give the dimensions of the solvated transition state.
Volume 57 Issue 1 January 1963 pp 13-24
A complete analysis of the work on the addition of bromine ethylene derivatives under varying conditions of structure, solvent and temperature brings out the composite nature of the reaction. With the Roberts-Kimball postulate as the starting-point, it is found that the variations in reaction order can be readily understood from the variations in the importance of the rate determining step. A mechanism incorporating all the details is presented.
Volume 59 Issue 2 February 1964 pp 93-101
Both structural and solvent influences on the rate of oxidation of a series of aromatic aldehydes by chromic acid show the following features: the formation of a chromate ester is not a prerequisite to oxidation; in the rate-determining step of the reaction the C-H hydrogen is removed as a hydride anion. That the rate-dermining step involves a two-electron transfer has been proved by a study of the Induction Factor method. A tentative mechanism, based on an analogy to the well-known ‘SN2’ process, has been proposed.
Volume 59 Issue 5 May 1964 pp 292-298
Volume 59 Issue 6 June 1964 pp 365-370
The dipole moments of three furan compounds studied in benzene solution indicate the hyperconjugation effect of the methyl group and the existtence of the alcohols primarily in the
Volume 60 Issue 3 September 1964 pp 201-210
The dipole moments of mono- and disubstituted
Volume 60 Issue 6 December 1964 pp 416-421
The effect of added salts and oxidizable cations on the chromic acid oxidation of aromatic aldehydes in acetic acid-water mixtures is discussed and a tentative scheme for the intermediate stages of reduction of the chromium species is presented.