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The acid-catalysed hydration of sym-dichloroacetone.
Full text linkPart of a continuing study m the kinetics and mechanism of the hydration of carbonyl compounds is reported. The kinetic effect of varying the composition of the aqueous dioxen solvent mixture was investigated for catalysis by water and seven acids, in order to provide a further test of the suggestion of Bell, Millington, and Pink ( Proc.Roy.Soe. A 1968, 303,1) that the water-catalysed reaction passes through a cyclic transition-state made up of the substrate and three water molecules, of which either one or two can be replaced by a molecule of catalyst according to its structure. Solvent deuterium isotope effects were also measured with a view to investigating the configuration of the transition-state.
The kinetics and equilibria of the hydration of sym-dlehloroaeotone were measured spectrophotometrically at 25°C in solutions of water mole fraction 0.086-0.320. The isotope effect on the dissociation constant, K, of the ketone hydrate was found to be
KD/KH = 0.915
Appreciable concentrations of catalyst led to increased values of K, which were analysed in terms of ground-state hydration of the catalysts.
The following kinetic orders with respect to water mole fraction were found for the hydration reaction:
CC13COOH 0.91, CH2C1COOH 0.98, C6H5COOH 0.92, CC13COOH 0.98,
0-C6H3C12COOH 2.5, H2O 3.65.
From the linear kinetic order plots it is argued that the slopes provide m approximate measure of the number of water molecules taken up in an intimate fashion In the activation equilibrium. Combination of these results with estimates of the degree of hydration of the catalyst suggests on balance, end in company with other evidence, that all the transition-states have similar structures.
Solvent isotope effect studies indicated that at least three water molecules are taken up la the water catalysed reaction, that the fractionation factor products for the different transitionstates are very similar, and that there is a primary contribution. For the hydration reaction kH/kD was found to be
HC1 1.23, HC104 1.29, CC13COOH 2.46, CH2C1COOH 2.92, C6H5COOH 2.76,
CH3COOH 2.94, H2O 3.97.
A simple model la proposed for the prediction of transition-state configurations and energies, and gives a reasonable account of the observed catalytic behaviour, isotope effects, and strueture-reactivlty relations. Carbon-oxygen bond formation occurs synchronously with proton transfer from the acid in the transitionstate, but the other proton transfers have been already carried to completion or have not yet started
Personality, payoff information and behaviour in a two-person bargaining game
Full text linkPrevious studies of the influence of personality on behaviour in experimental games have provided conflicting and inconclusive results. The present investigation was designed to search on a broad front for personality correlates of behaviour in a two-person bargaining game, the one used being a derivation of the Deutsch and Krauss Trucking Game. Five personality tests, covering fifty-three personality traits, were administered to 192 undergraduate students attending courses at The University of Stirling, and from these the experimental groups were randomly chosen, the only constraint being the sex of the subjects. The tests were The Sixteen Personality Factor Questionnaire, The Guilford/Zimmerman Temperament Survey, The Study of Values Test, The Edwards Personal Preference Schedule, and The Test of Social Insight. The trucking game was played for 30 trials by two groups of subjects, each containing 24 male dyads and 24 female dyads, under two experimental conditions: Condition I, where subjects had access to full information regarding the other's payoffs, and Condition II, where only incomplete information of the other's payoffs was available. It was hypothesized that behaviour in the game would be influenced by (i) amount of information available about the payoffs of the other; (ii) sex of the players (comparing single-sexed dyads); and (iii) players' personality. No differences due to either amount of information available about the other's payoffs, or sex of the players, were found. An analysis of the data provided by the combined experimental groups, however, successfully located indications of personality effects on behaviour in the game, as measured by total joint payoff summed over 30 trials, total time taken, the number of concessions made to the other player, and first strategy-choice on individual trials. The personality variables concerned were Emotional Stability and Radicalism/Conservatism, (Factors C and Ql of The Sixteen Personality Factor Questionnaire); Personal Relations, (Factor P of The Guilford/Zimmerman Temperament Survey); Theoretical Value, (T scale of The Study of Values Test); Exhibition, ('exh' variable of The Edwards Personal Preference Schedule); and Cooperativeness, (Scale III of The Test of Social Insight). It is suggested that the relationship of these personality variables to game-playing behaviour should be the subject of further investigation
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