4-chloro-a-methylstyrene

A different chlorinated polystyrene is indicated in literature [1] as poly(chlorostyrene), CAS 9022-52-0. Halogenated polystyrenes also include poly(p-chloro-a-methylstyrene), poly[p-(2,4-dichlorobenzyl)-styrene], etc. Thermal degradation, not necessarily by flash pyrolysis, has been studied and reported for a number of halogenated polystyrenes [2, 3], and poly(a-methylstyrenes). Some of these reports are summarized in Table 6.4.1 [1]. 

KOH in 1850 ml of methanol]. The methanol is removed by distillation and the remaining liquid is washed with water, dried with calcium chloride, and distilled through an efficient column under reduced pressure to give 90 gm (26%) of 3-chloro-2-methyl-a-methylstyrene, bp (A°-65°C (4 mm), 1.5340 and 152 gm (48%) of 3-chloro-4-methyl-a-methylstyrene, bp 73°-74°C (4 mm), 1.5520. The purity of these materials should be checked by gas chromatography. 

The initial series of major tranquilizers consists of alkylated derivatives of 4-aryl-4-hydroxypiperidines. Construction of this ring system is accomplished by a set of rather unusual reactions. Condensation of methylstyrenes with formaldehyde and ammonium chloride afford the corresponding hexahydro-1,3-oxazines (119). Heating these oxazines in the presence of acid leads to rearrangement with loss of water to the tetrahydropyridines. Scheme 1 shows a possible reaction pathway for these transformations. Addition of hydrogen bromide affords the expected 4-bromo compound (121). This last is easily displaced by water to lead to the desired alcohol (122) The side chain (123) is obtained by Friedel-Crafts acylation of p-fluorobenzene with 4-chloro-butyryl chloride. Alkylation of the appropriate arylpiperidinol with 123 affords the desired butyrophenone derivative. Thus,... 

Chloro-2,4-diphenyl-4-methylpentane (adduct of a-methylstyrene dimer and hydrogen chloride) Difurylmethane... 

The rates of initiation and propagation are comparable when the covalent initiator and dormant chain ends have similar structures. Therefore, 1-phenylethyl precursors are useful initiators for styrene polymerizations, but are poor initiators for a-methylstyrene and vinyl ether polymerizations. Similarly, cumyl derivatives are good initiators for isobutene and styrene, but are poor initiators for vinyl ethers their initiation of a -methylstyrene is apparently slow [165]. 1-Alkoxyethyl derivatives are successful initiators for vinyl ethers, styrenes, and presumably isobutene polymerizations [165,192]. /-Butyl derivatives initiate polymerization of isobutene slowly [105]. This is mirrored in model studies that show that /-butyl chloride undergoes solvolysis approximately 30 times slower than 2-chloro-2,4,4-trimethylpentane [193]. This may be due to insufficient B-strain in monomeric tertiary precursors [194]. In contrast, monomeric and dimeric or polymeric structures of secondary esters and halides apparently have similar reactivity. 

Figure 4.20 Scanning transmission electron micrograph of a precursor membrane for an anion exchange membrane (cross-linking 20%) A pasty mixture of chloro-methylstyrene and divinylbenzene was copolymerized in the presence of acrylonitrile—butadiene rubber (inert polymer) ratio of divinylbenzene to total vinyl monomers 20%.

MPR)TPP)C0 epoxidized a variety of alkenes with Cl2pyNO as oxidant, the chloro system giving higher yields (56-98%) with Ru (8.6 wt.%.) oxidant substrate = 1 14(X) KXX), in benzene, atr. t. for 24 h. Cw-stilbene and norbomene yield exclusively cM-epoxides. In contrast, with the M-41(m) system, the Ru((4-Cl)i 4-MPR)TPP)CO polymer oxidized frani-stilbene and rra j-P-methylstyrene to the corresponding trans epoxides in 90 and 86 % yields, respectively. Several alkenes were oxidized catalytically for the first time with high selectivity 3,4-dihydronaphthalene yielded 62% epoxide. 

Full details have been given for the preparation of chloro(phenyl)carbene (3), from the corresponding diazirine, and for its subsequent trapping by /3-methylstyrene, leading to the cyclopropene (4) after dehydrochlorination. An excellent new catalyst for the synthesis of cyclopropanecarboxylates (5), from olefins and diazoesters, is the rhodium cluster compound, Rh6(CO)i6. In general, good yields of (5) are only obtained if a large excess of olefin is used, but other work... 

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