Formation Of Methyl Chloride Research Articles

The kinetics and mechanisms of the gas phase elimination of 4‐(methylthio)‐1‐butyl acetate and 1‐chloro‐4‐(methylthio)‐butane

AbstractThe gas phase elimination of 4‐(methylthio)‐1‐butyl acetate and 1‐chloro‐4‐(methylthio)‐butane has been investigated in a seasoned, static reaction vessel over the temperature range of 310–410°C and the pressure range of 46–193 Torr. The presence of the inhibitors propene, cyclohexene, and/or toluene had no effect on the rates. The reactions are homogeneous, unimolecular, and obey a first‐order rate law. The rate coefficients are given by the following Arrhenius equations: for 4‐(methylthio)‐1‐butyl acetate, log k1(s−1) = (12.32 ± 0.29) − (192.1 ± 3.6) kJ/mol/2.303RT; for 1‐chloro‐4‐(methylthio)‐butane, log k1(s−1) = (12.23 ± 0.59) − (175.7 ± 6.8) kJ/mol/2.303RT. The CH3S substituent in 1‐chloro‐4‐(methylthio)‐butane has been found to participate in the elimination reaction, where tetrahydrothiophene and methyl chloride formation may result from an intimate ion‐pair type of mechanism. The yield of a cyclic product in gas phase reactions provides additional evidence of an intimate ion pair mechanism through neighboring group participation in gas phase elimination of special types of organic halides.

Degradation of vinylidene chloride/methyl acrylate/phenylacetylene (VDC/MA/PA) terpolymers. Effect of internal unsaturation on the stability of Saran copolymers

AbstractThe thermal degradation of vinylidene chloride/methyl acrylate/phenylacetylene (VDC/MA/PA) terpolymers containing a constant 9 wt % methyl acrylate and small but varying amounts of phenylacetylene has been examined in the solid phase and in bibenzyl solution. Thermally promoted degradative dehydrochlorination, largely uncomplicated by methyl chloride formation, readily occurs at temperatures approaching 200°C. Incorporation of phenylacetylene into the polymer structure greatly facilitates degradative dehydrochlorination. Indeed, the presence of phenylacetylene induces the formation of polyene segments during the polymerization so that all the terpolymers, even at very low phenylacetylene loading, are tan in color. The decreased stability of polymers containing internal unsaturation arises from an increased rate of initiation for the degradation reaction. The propagation rate is largely unaffected by the level of unsaturation initially present in the polymer. Thus random double bonds have been identified as the principal defect sites responsible for the facile degradation of Saran copolymers. Species which promote the degradation of Saran polymers probably do so by facilitating the introduction of double bonds into the structure. The ratio of hydrogen chloride to stilbene formed for degradation of the terpolymers in bibenzyl solution is ca. 35:1. This is strongly reminiscent of PVDC degradation and suggests that for degradation of either the homopolymer or Saran copolymers the chain‐carrying allylic radical pair does not dissociate to any appreciable extent as dehydrochlorination occurs.

Mechanism of thermolysis of tetramethylammonium μ-chlorobis(triethylaluminate)

The thermolysis of tetramethylammonium μ-chlorobis(triethylaluminate) has been investigated. In addition to the previously reported products, [Me 4N][ClAlEt 3] and (AlEt 3) 2, Me 3N · AlEt 3 is formed simultaneously in lesser amounts. A mechanism for the observed thermolysis reactions is presented which predicts formation of methyl chloride as a transient species which undergoes further reaction with (AlEt 3) 2 to ultimately produce methane and ethylene. The experimentally observed methane/ethylene ratio supports the proposed mechanism.

Formation of Methyl Chloride During Methyl Bromide Fumigations2

Formation of Methyl Chloride During Methyl Bromide Fumigations2

Degradation thermique des copolymeres poly(methacrylate de methyle-chlorure de vinyle)—I. Relation avec la distribution des sequences

The study of the thermal degradation of random vinylchloride-methylmethacrylate copolymers, with programmed temperature between room temperature and 400°, has been carried out using simultaneously thermogravimetry, continuous potentiometric or discontinuous acidimetric hydrochloric acid titration, and quantitative analysis of volatile products by gas-phase chromatography. There have been independent studies of the different reactions observed, namely lactonization between two adjacent units with methyl chloride formation, further formation of this product by reaction between nascent hydrogen chloride and methylmethacrylate units, dehydrochlorination, benzene formation through cyclization of dehydrochlorinated vinyl chloride sequences, and finally depolymerization of methylmethacrylate sequences. There is a quantitative relation between their contributions and the sequence distribution.

Photolysis of acetyl chloride

Irradiation of acetyl chloride in the gas phase with light from a medium-pressure mercury-vapour lamp leads to the formation of carbon monoxide, methyl chloride, vinyl chloride, and polymer. The energy of activation for the formation of methyl chloride is 15·5 ± 0·5 kcal. mole–1 and that for the formation of vinyl chloride is 20·4 ± 0·5 kcal. mole–1.

Reactivity of Solid Acids with Methylene Chloride

Abstract In order to discriminate the natures of solid acids, the reactivity of methylene chloride with solid acids like alumina, silica-alumina and alumina-boria to give carbon monoxide and methyl chloride was studied with a pulse technique. The reactivities varied about ten thousandfold among these solid acids. The methyl chloride formation was predominant on alumina particularly at low reaction temperatures, with a distinctly small activation energy in comparison with that on silica-alumina or alumina-boria. The nature of the active sites for this reaction was discussed in connection with the effect of the calcination temperature as well as of the sodium ion-poisoning on activity. Furthermore, it was found that the feature of this reaction was in marked contrast with the typical solid acid catalysis such as the dealkylation reaction of alkylbenzenes. The reaction of methylene chloride with a set of the surface hydroxyl group and the oxidizing site is assumed to give methyl chloride through a radical mechanism.