Reactions of iodine with olefins. 5. The systematics of electrophilic high energy iodine in gaseous, high pressure, and liquid isomers of butene

Abstract

Reactions of Iodine with OlefinsThe Molar Extinction Coefficients for H2NC(-0)ÑH and HÑCN. Figure 4c summarizes the absorption spectra and the molar extinction coefficients for the radicals produced by the reaction of hydroxyl radicals with cyanamide. They are mainly derived from the experimental data obtained with 4.6-20 krd per pulse and with 0.5 M NH2CN solutions (pH 5). For the computations of the free radical concentrations, the reaction scheme included reactions 1-8, 12-16, and 20-22. Concluding Remarks(1) The results obtained in this work offer a fairly complete picture of the early stages of the radiolysis of NH2CN in aqueous solutions at pH 5. When the proposed reaction scheme is used in computer simulation of the reaction mechanism, the computed rate curves agree with the experimental ones within 15%. This is considered a fair agreement because of the large range of experimental conditions under which the testing was carried out (1.85-26.7 krd/pulse, 0.025-1 M NH2CN).(2) This study shows that the cyano group in NH2CN is the main point of attack by hydroxyl radical, hydrogen atom, and hydrated electron, as was the case for the >C-CN molecules and various cyanides previously studied.

High Energy Reactions of Electrophilic Recoil Iodine-128 with Gaseous and Liquid cis-2-pentene

“…In our study of the reactions of high energy iodine-128 with gas phase butene isomers [8,9], greater than 70% of the total organic product yield was the result of attack at or near the double bond. For all the olefins through the butene isomers, general traits common to these systems were characterized.…”

“…Product formation routes of recoil iodine-128 are diverse involving high energy, photochemical and ion-molecule reactions. Unlike tritium and light halogens activated by nuclear transformations, (n, 7)-activated iodine shows higher selectivity in olefin systems [8,9], demonstrating electrophilic attack at or near the double bond. This attack involving high energy or excited positive iodine ions [11 ] or diiodine positive ions [7,9] can lead to the formation of reaction complexes, which can react further by various available mechanistic routes; e. g., decomposition, stabilization, abstraction, elimination or bimolecular combination.…”

“…Reactions of iodine-128, activated by nuclear recoil techniques, have been studied in gaseous and liquid alkane [1 -3], alkene [4][5][6][7][8][9], and alkyne [10][11][12]systems. Product formation routes of recoil iodine-128 are diverse involving high energy, photochemical and ion-molecule reactions.…”

Liquid Phase Hot Atom Chemistry: At Crossroads

“…The reactions of iodine with acetylene and propyne in the gas [28] c see reference [24] d see reference [29] and condensed phase occur mainly by complex formation with subsequent decomposition, stabilization or addition reaction modes. On the other hand, iodine reactions with olefins are exceedingly complex; little can be said about the nature of liquid state enhancement except where a complex is involved.…”

Recent Developments in Gas-Phase Hot Atom Chemistry

“…That the reactions of recoil iodine were due to a complex mixture of ions, electronically excited atoms and ions and translationally excited species was shown by the effect of carefully chosen additives to the system recoil iodine-methane a considerable time ago [7]. The present study has extended the range of hydrocarbons investigated to olefines (butene-1 [38], cis-and transbutene-2 and 2-methyl propene [39]) and to acetylenes (propyne [40] and butyne [41 ]). From the butenes labelled methyl iodide is usually the major radioactive product whilst the largest yields of labelled products from the acetylenes can usually be rationlaised as having been derived from addition at the triple bond.…”