Ct-Methylstyrene

The ability of the model to account for changes in liquid physical properties and mass velocities and correctly predict reactor performance is demonstrated using hydrogenation of ct-methylstyrene in various organic solvents as a test reaction. 

Production of Ct-methylstyrene (AMS) from cumene by dehydrogenation was practiced commercially by Dow until 1977. It is now produced as a by-product in the production of phenol and acetone from cumene. Cumene is manufactured by alkylation of benzene with propylene. In the phenol—acetone process, cumene is oxidized in the liquid phase thermally to cumene hydroperoxide. The hydroperoxide is split into phenol and acetone by a cleavage reaction catalyzed by sulfur dioxide. Up to 2% of the cumene is converted to Ct-methylstyrene. Phenol and acetone are large-volume chemicals and the supply of the by-product Ct-methylstyrene is well in excess of its demand. Producers are forced to hydrogenate it back to cumene for recycle to the phenol—acetone plant. Estimated plant capacities of the U.S. producers of Ct-methylstyrene are listed in Table 13 (80). 

Synthetic butadiene methylstyrene rubber of various grades. Butadiene-ct-methylstyrene rubbers ( hot and cold free radical copolymerisation of butadiene with a-methylstyrene), at the stages of emulsion formation, emulsion mixing with an initiator, and introducing a terminator to the reaction mixture. 

Boileau, Kaempf, Schue and coworkers have studied the cryptate mediated anionic addition polymerization of several systems including ethylene oxide [38], propylene sulfide [39-40], isobutylene sulfide [40], isoprene [38], methyl methacrylate [38], hexamethyl trisiloxane [40], e-caprolactone [41], styrene [38, 40, 41], ct-methylstyrene [41], 1,1-diphenylethylene [41] and /3-propiolactone [42]. The polymerization of the latter compound induced by dibenzo-18-crown-6 complexed sodium acetate has also been reported [43]. In general, it was found that the polymer-... 

More recently, chloramine-T (CT) was found to be an efficient nitrogen source for the aziridination of olefins by our group [7a], Among the transition metals, copper(I) chloride was the most suitable catalyst for the aziridination of olefins with CT. For example, frans-P-methylstyrene was successfully aziridinated with CT at 25 °C in acetonitrile in the presence of a catalytic amount of CuCl (Scheme 6). Other olefins have also been aziridinated by the reaction, whose products are shown in Scheme 7. 

Scheme 6. Copper-catalyzed aziridination of frans-fl-methylstyrene with CT.

Recently, it was found that the common CT agent a-methylstyrene dimer operates by an addition-fragmentation mechanism (Figure 24.4). [10]... 

Conversion of a-methylstyrene to cumene CT=400C) Pd AI2O3 (tube) Reaction rate increased up to 20 times that of uicklebed reactor Ciniand Harold, 1991... 

Table 5 lists some selected copolymerization reactivity ratios. It is clear from the data that the monomer yielding the more stable carbocation dominates the copolymerization. Considering the importance of carbocation stability, it is not surprising that in some instances reasonable correlation was obtained between log(l/ri) and Hammett s a or Brown s ct+ values of the substituents of the second monomer. Examples are the copolymerization of a-methylstyrene with substituted styrenes (169) or styrene with substituted 1- and 2-phenylbutadienes (172). It is thus expected that ideal copolymerization (ri = T2 = 1) in carbocationic systems is imlikely— the only reported ideal system is the copolymerization of... 

Among the aryl olefins, 1,1-diphenylethylene is half-protonated in 71% H2SO4 (Deno ct al., 1959). Although ultraviolet spectra (Deno et al., 1960 Grace and Symons, 1959) and half-protonation points (Deno et al., 1960) have been reported for a-methylstyrene and other monoaryl olefins, we now know that some of these observations were made on rearranged and polymerized carbonium ions. The following two equations represent valid cases of protonation of monoaryl olefins. 

Poly(styrene-ct)-A7-(pentachlorophenyl)- 310 and 500 Styrene, benzene, toluene, ethylbenzene, allylbenzene, a-methylstyrene. 174... 

Acetonyl methacrylate Acrylic acid-ct -carbitylacrylate-co-cc-methylstyrene-co-styrene Acrylonitrile-co-n-butyl acrylate Alkyl acrylate... 

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