The commercial development of the sulfuric acid alkylation process has gone forward very rapidly upon the basis of relatively simple and empirical assumptions and it has been estimated that by the fall of 1940, plants had been installed capable of producing over 7,200,000 barrels per year of 92-94 octane number fuel (unleaded) from C4 olefins and isobutane alone (1). While the practical aspects of the process are well known, the underlying reaction-mechanism is apparently rather complex and thus far no entirely satisfactory theory has been presented which would account for the products obtained. These differ greatly from those that would be predicted if the isoparaffin had added to the double bond in the expected manner.Furthermore, hydrocarbons of molecular weight both lower and higher than those to be expected are obtained. There remains, therefore, considerable incentive for further study.Birch et al.(2) have presented considerable data which would indicate that no single reaction-mechanism will account for all the products and they conclude that isomerization of the primary products is at least partially responsible for the structure of the hydrocarbons of the expected molecular weight.As the result of our study of a wider variety of isoparaffins and olefin feed stocks we have come to a somewhat different view of the reactionmechanism. This view envisages both carbon-to-carbon cleavage and dehydrogenation of the primary isoparaffins as taking place in the alkylation reaction.A discussion of the experimental data which lead to this view follows.EXPERIMENTAL Both batch and continuous operation were employed in the experiments about to be discussed.The batch experiments were made in a high-speed mechanical mixer; the olefin was added slowly to a mixture of acid and excess isoparaffin. A similar reactor with the addition of a separator was used in the continuous experiments. A high isoparaffin-olefin ratio is obtained in the reaction zone by first blending the olefin with an excess of isobutane and then feeding this mixture into a reactor containing an 647
It has been shown that the cleavage of methyl ketones by the action of hypohalite solutions involves the intermediate formation of corresponding trihalomethyl ketones. These intermediates have been found to be stable to cold solutions of alkali in those cases in which the positions ortho to the carbonyl group are occupied. The stabilizing effect of methyl groups' and of bromine atoms2 in the ortho positions has been found to be very great. Cleavage of the trihalomethyl ketones in these cases has been effected only by long treatment with hot, concentrated solutions of alkali. The effect of methoxy groups3 has, however, proved to be less pronounced. The di-o-methoxy trihalomethyl ketones, while sufficiently stable toward cold solutions of alkali, have been found to be cleaved readily by hot alkaline solutions.The present paper is a report of a similar study of the effect of ortho chlorine atoms For this purpose 2,4,6-trichloroacetophenone (I) was used.
COCHzClCOCH3 COCl I
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