The reactions of t-butyl peroxide with toluene derivatives

Abstract

The reactions of t-butyl peroxide with toluene derivatives, containing chloro-, bromo-, cyano-, methyl-, and phenylsubstituents in the alkyl side chain andp-halogeno-substituents in the nucleus, givevariable yields of the corresponding dehydro-dimers. Good yields are obtained with the p-halogeno-substituted cumenes, benzyl cyanide, p-chlorobenzyl cyanide, benzylidene dichloride, and p-bromoethylbenzene. a-Chloroethylbenzene, benzyl bromide, benzyl chloride, p-chlorobenzyl chloride, and p-tolunitrile give moderate to low yields of the expected dimers. However, p-bromobenzyl bromide, a-bromoethylbenzene, a-bromophenylacetonitrile, and diphenylbromomethane fail to dimerise in the expected manner. The available evidence in the case of diphenylchloromethane suggests that both hydrogen and chlorine are abstracted, giving rise to a variety of mixed products.FREE methyl radicals, liberated by thermolysis of acetyl peroxide, have long been known to abstract hydrogen atoms from the carbon atom adjacent to the unsaturated group in substances such as alkylbenzenes, ketones, acids, and esters1 More recently, similar behaviour has also been observed with t-butyl peroxide in its reactions with compounds containing the ArCH : nu~leus.~-4 This selectivity has been attributed to the effectiveness with which the t-butyloxy-radical can function as a dehydrogenating agent, when it is released from the thermal decomposition of t-butyl peroxide in a solvent. It has been established3'4 that the course followed by these homolytic reactions with t-butyl peroxide is largely determined by the relative stability of the secondary radical produced by hydrogen abstraction, provided polar-orienting and steric effects

Synthesis and fabrication of GPS patch antennas by using Zn(1 − x)Ti x Al2O4 thin films

“…1), while the intensity of ZnAl 2 O 4 phase decreases. The observed diffraction peaks of ZnAl 2 O 4 -doped TiO 2 result are consistent with the previously reported [6][7][8]10]. Furthermore, the peak positions of the phases shift slightly toward the higher angle with increasing x, which suggests a reduction in the unitcell dimension due to the improvement of crystallizability.…”

“…It has been used as catalyst support, ceramic materials, electronics, and optical materials [9]. At present, some researchers studied the dielectric properties of ZnAl 2 O 4 doped with TiO 2 as microwave dielectric ceramics [6,[10][11][12][13]. Accordingly, they have found that ZnAl 2 O 4 doped with TiO 2 ceramics has excellent properties and has a very extensive prospect to be used as microwave substrates and for antenna applications in the future.…”

“…These factors play important roles to produce ZnAl 2 O 4 doped with TiO 2 materials. Recently, there are many methods to prepare ZnAl 2 O 4 doped with TiO 2 as MDC such as solid-state mixing reaction [11,12], mixed oxide route [6,10], and molten-salt process [13]. However, the sintering temperature of the previous methods is too high ([1300°C) and needs to be decreased.…”

“…ZnAl 2 O 4 ceramics has been selected due to their dielectric constant value, e r * 8.5 [6], and wide energy band gap, E g * 3.8 eV [7,8]. Furthermore, ZnAl 2 O 4 has been studied for decades and attracted attentions of many researchers due to their unique properties of ZnAl 2 O 4 such as crystal chemistry, crystal structures, and physical properties.…”

Thermochromism of 1,2,5-triphenylphosphole and the formation of 1,1,2,2-tetrachloro-1,2-diphenylethane from α,α,α-trichlorotoluene

“…Tetrachlorotolan, however, has been obtained from trichlorotoluene using red phosphorus in the presence of hydroiodic acid (25), elemental sulfur ( 1 3 , di-tertiarybutyl peroxide (26), and finely powdered tin (27), all reducing systems for the generation of radicals. Considering these examples, in the light of our own experiments, it was possible that the coloured species formed with 1,2,5-triphenylphosphole in boiling a ,a ,a-trichlorotoluene was the radical species 6 thermally produced in equilibrium with the phosphonium salt 5, neither of which arise to any significant extent at ambient temperatures.…”