Propyl iodide, reaction

Consider the reaction of ethyl propyl ether with HI. Write the two different possible product combinations. Compare e energies of the two products 1-propanol and ethyl iodide-, ethanol and 1-propyl iodide). Which is the lower-energy combination Is the energy difference significant (>.002 au or 1 kcal/mol) Based on thermochemistry alone, is this reaction Likely to be selective Explain. 

The gas-phase reactions of the fulvene radical cation with neutral 1,3-butadiene, alkenes and 2-propyl iodide have been investigated by Russell and Gross131a using ICR mass spectrometry. Unlike ionized benzene, ionized fulvene undergoes no C—C coupling with 2-propyl iodide. On the basis of deuterium and 13C labelling, the reaction of ionized fulvene with 1,3-butadiene was suggested to occur by [6 + 4] cycloaddition to yield tetrahydroazulene radical cations. Cycloadditions of neutral fulvene were also studied in this work. 

All data obtained on the rate of reaction of [Ni(NiL2)2]Cl2 with alkyl halides— i.e., methyl iodide, benzyl bromide, benzyl chloride, p-nitrobenzyl chloride, p-chlorobenzyl chloride, ethyl bromide, ethyl iodide, n-propyl bromide, and n-propyl iodide—conform closely to a pseudo-first-order rate law. Almost all experiments were carried out in the presence of an excess of alkyl halide. Since methanol solutions of the alkylated complexes have only negligible absorption at 495 m//, rates were obtained by graphs of log A0—A vs. time. The graphs are linear over the entire time interval, which corresponds to more than two half lives in most cases, passing through the origin at zero time. The rate is essentially the same whether measured by the spectrophotometric or conductivity method. 

Alkyl halides, acyl halides, anhydrides, and related substances. It was discovered as early as 1861 by Rcboul and Luurenool<4t> that epicblorohydrin may be caused to react with ethyl bromide on heating in a sealed tube to an elevated temperature. The product isolated from this condensation was ]-broJHo-3-chloro-2-ethoxyprt>pane. Some year later Paalli6 extended this reaction to include also methyl iodide, ethyl iodide, n-propyl iodide, and isopropyl iodide do2-propunol was formed. 

The primary iodide is never formed in such reactions. Preparation 123.—iso-Propyl Iodide [2-Iodopropan]. 

About 5% of the ethyl radical adduct was isolated in the reaction with r-butyl iodide and about 20% of the ethyl radical adduct was formed in the reaction with i-propyl iodide. These ratios compare quite well with those calculated by using the rate constants for halogen transfer in the above reference and the rate constants for addition of a primary radical to methyl vinyl ketone. 

The products were isolated as esters by reaction of the acylcobalt carbonyls with an alcohol and iodine. In the case of the alkyl halides, carbon monoxide was normally absorbed, but under nitrogen, acylcobalt tricarbonyls must be formed. The reaction with alkyl halides was slow and some isomerization was noted using M-propyl iodide (formation of n-butyrates and isobutyrates). Absence of carbon monoxide promoted the isomerization. Isopropyl iodide gave no reaction. When ethyl a-bromopropionate was used, no isomerization was found at — 25 °C under carbon monoxide, but the isomerized product, diethyl succinate, was the major product at 25° C under carbon monoxide or nitrogen. Under the conditions of the experiments no isomerization of the alkyl halide itself was found. 

Lithioethenyl phenyl tellurium was not alkylated by 1-propyl iodide or allyl bromide. Only diphenyl ditellurium and ethenyl phenyl tellurium were isolated from the reaction mixtures1. 

Selective /3-allylation and /3-alkylation was observed when Goswami s dianion was reacted with allyl bromide and propyl iodide (Scheme 16)9. The dianion undergoes isomerization to the a,a -dianion at 0 °C and, as a result, the reaction must be conducted carefully at low temperatures. 

Ueda et al. reported a tandem radical addition-cycUzation reaction in aqueous media [184]. This reaction was initiated by single-electron transfer from indium to an alkyl iodide. Fragmentation of the iso-propyl iodide radical anion generated the iso-propyl radical, which triggered the addition/cyclization tandem. Final SET and in situ hydrolysis delivered cyclic sulfonamides in good yield but low stereoselectivity. 

Table I 4) a) shows that allyl iodide decomposes much more readily than any of those previously described. At 494 decomposition was almost 60 %, so that in order to obtain more moderate decomposition lower temperatures had to be chosen. Exps. 77-78 show the absence of any effect of iodide-pressure on the rate. The comparison of these results with Exp. 80 reveals a fourfold increase of Ai caused by a twelvefold reduction of the contact time. Exps. 84, 78, 82 and 86, carried out at the lower temperature of about 356° again show Aj as independent of the iodide pressure. Comparing Exp. 84 with Exps. 78, 82 and 86, and the latter with Exps. 89 and 81, we see also that the rise of Aj with diminishing contact time has become less marked— if not altogether negligible. With a further lowering of the temperature to about 298° (Exps. 83, 79, 85, 88) the dependence of Ai on contact time becomes quite imperceptible. Thus with decreasing temperature the kinetics of the reaction appear to conform increasingly well to the monomolecular scheme. Extrapolating the rate of pyrolysis of -propyl iodide down to 298°, the ratio of Aj for -propyl allyl can be calculated at about i 14000.

We may use the observations listed above to derive in some cases the temperature coefficients of the rate of pyrolysis and hence the activation energy of the reaction. For w-propyl iodide and n-butyl iodide we have sufficiently reliable data for two temperatures from which we calculate for -propyl 0 = 52 kcal. and for -butyl Q = 53 kcal. This lends support to the value of similar magnitude, Q — 55 kcal., obtained from the otherwise less reliable Exps. 3, 4, and 6, 7, 8 for ethyl iodide. 

This reaction should be done in a well-ventilated hood, t The decaborane is purified by sublimation at 60° and lO" mm. t The n-propyl isocyanide is prepared by the method of Jackson and McKusick/ using 490 g. (2.S mole) of n-propyl iodide and 454 g. (3.3 mole) of silver cyanide. It is observed that, after a long induction period, the reaction becomes quite violent. It is suggested that one half of the propyl iodide be added initially and the other half be added drop by drop over a 2-hour period. The drj- product is used without the final fractional distillation indicated in the reference. 

A series of other halogenated compounds have been identihed in seawater, including ethyl iodide, propyl iodide, bromoiodomethane, chloro-iodomethane, and di-iodomethane (Carpenter et al., 2000 Klick and Abrahamsson, 1992). Little is known about their production mechanisms. Loss mechanisms are likely to include photolysis and reaction with chloride and hydroxide ions. Information is too limited to be used to derive global fluxes for these compounds, although the data available indicate that a reasonable case can be made that the iodine flux from these compounds is similar to that from CH3I. 

Primary process I. (i) The participation of free radicals in the formation of carbon monoxide and propane is indicated by the strong temperature dependence of (f>co and ciHa in the uninhibited reaction, and by the considerable inhibition of CO and C3H8 formation by iodine, (ii) The occurrence of C3H6 and in the uninhibited reaction and their absence in the inhibited one are evidence for the formation of the n-C3H7 radical. Hi) Propyl iodide is a product in the presence of iodine the values of level off above about 2 torr iodine pressure. This limit is independent of the temperature. Accordingly, (j>i = in ih presence... 

Propane and Butane.— In this way propane, CaHg, has been made from ethyl iodide, methyl iodide and sodium and it must therefore be methyl ethane. Also butane, C4H10, similarly made from propyl iodide, methyl iodide and sodium, is methyl propane. The reactions are as follows ... 

Synthesis of the Two Butanes.—The two isomeric propyl iodides, by means of the Wurtz and Frankland reactions, yield the two isomeric butanes, the constitution of which must, therefore, be as shown in the following reactions ... 

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