Ethyl bromide pyrolysis

Apart from the molecular and the radical-chain mechanisms for the decomposition of halogenated hydrocarbons, the study of allyl bromide pyrolysis " revealed a third possibility, namely a radical non-chain mechanism, a type originally proposed by Daniels and Veltman for ethyl bromide pyrolysis. Its application to allyl bromide pyrolysis is shown in the following scheme as proposed by Maccoll ... 

For rate studies of pyrolysis of some p-alkyl substituted ethyl bromides, see Chuchani, G. Rotinov, A. Dominguez, R.M. Martin, I. Int. J. Chem. Kinet., 1987, 19, 781. 

The pyrolysis of ethyl bromide was found to be of the first order with specific rates... 

The two parallel thermal decompositions of bromopropane-1,1,2,2-d4, together with the decomposition of ethyl bromide, have been investigated by using the very low-pressure pyrolysis (VLPP) method107 (equations 20 and 21). 

N. Capon (1964) has shown that, in the case of ethyl bromide, nitric oxide actually increases rather than inhibits the rate of pyrolysis. 

The next three procedures provide useful synthetic intermediates. A stereospecific synthesis of ETHYL (Z)-3-BROMO-2-PROPENOATE affords an alternative vinyl bromide partner for the coupling chemistry in the preceding procedure. A very simple but elegant illustration of the flash vacuum pyrolysis technique is used to prepare BENZOCYCLOBUTENONE from o-toluoyl chloride. Another member of the functionalized indole family of synthetic intermediates is presented in a four-step procedure for 5-METHOXYINDOLE-2-ACETIC ACID METHYL ESTER. 

The reaction of ketocarbenoids with pyrroles leads to either substitution or cyclopropanation products, depending on the functionality on nitrogen. With N-acylated pyrrole (209) reaction of ethyl diazoacetate in the presence of copper(I) bromide generated the 2-azabicyclo[3.1.0]hex-3-ene system (210) and some of the diadduct (211 Scheme 44).162163 On attempted distillation of (210) in the presence of copper(I) bromide rearrangement to the 2-pyrrolylacetate (212) occurred, which was considered to proceed through the dipolar intermediate (213). In contrast, on flash vacuum pyrolysis (210) was transformed to the dihydropyridine (214). A plausible mechanism for the formation of (214) involved rearrangement of (210) to the acyclic imine (215), which then underwent a 6ir-electrocyclization. 

Ethane occurs in natural gas, from which it is isolated. Ethane is among the chemically less reactive organic substances. However, ethane reacts with chlorine and bromine to form substitution compounds. Ethyl iodide, bromide, or chlorides are preferably made by reaction with ethyl alcohol and the appropriate phosphorus halide. Important ethane derivatives, by successive oxidation, are ethyl alcohol, acetaldehyde, and acetic acid. Ethane can also be used for the production of aromatics by pyrolysis (Fig. 1). 

Pentadiene has been prepared by the interaction of allyl bromide and vinyl bromide in the presence of magnesium,8 by the pyrolysis of 1,5-pentanediol diacetate 5-6 or 4-penten-l-ol acetate,6-9 and by the reaction of < -allyl-/3-bromoethyl ethyl ether with zinc.10-11 The present procedure is based on the work of Schniepp and Geller6 and of Paul and Tchelitcheff. 6... 

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