Pressure Studies with Benzyl Acetate

Rate constants for the ion-molecule reactions occurring in chemical ionization can be obtained from studies of the pressure dependence of ion intensities. The effect of benzyl acetate pressure on the chemical ionization mass spectrum of benzyl acetate obtained with has been investigated 

Applying the usual pseudo-first-order kinetic considerations to this system, we write 

Here /ebzac+ Is th sum of intensities of all ions formed from BzAc, /( -c.h, is the sum of the intensities of all ions, t is the residence time of t-C4H9 ions 

At higher pressures of the additive one can observe ion-molecule reactions between fragments from the additive and the additive molecules. Thus at the higher pressures of benzyl acetate one observes an alkylation which may be represented as 

The rate constant for the formation of the mje = 181 ion may be obtained fromthepressurestudies with benzyl acetate, and a value fci81 = 3.8 x 10 cm molecule sec is obtained. This is also quite reasonable. 

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Kinetic studies of various systems have been carried out as follows the reaction of 2,2 -dichlorodiethyl sulfide and of 2-chloroethyl ethyl sulfide with diethylenetriamine and triethylamine in 2-methoxyethanol ° the catalysed reactions of substituted phenols with epichlorohydrin the reactions of para-substituted benzyl bromides with isoquinoline under high pressure the reactions of O-alkylisoureas with OH-acidic compounds [the actual system was N, N -dicyclohexyl-0-(l-methylheptyl)isourea with acetic acid] and tlie ring opening of isatin in aqueous binary mixtures of methanol and acetonitrile cosol vents. 

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