Ot -Methylstyrene

When naphthalene is substituted by a polyvinyl aromatic chain polystyrene PS, poly(p-tert-butylstyrene) PTBS or poly(ot-methylstyrene) PMS the course of the metalation is deeply modified (21, 22, 25.). 

The cationic polymerization of vinyl monomers such as isobutene, styrene, ot-methylstyrene, indene, and vinyl ethers is generally impeded by several transfer processes65 . The molecular weight of the polymer is not determined by the molar ratio of monomer to initiator. Therefore, the methods that are based on the long lifetime of the active sites at the chain ends cannot be applied here. 

Poly(ot-methylstyrene-co-styrene) was previously prepared by Desbois [5] using s-butyl lithium and triisobutylalumimim. 

Ot-Methylstyrene. This compound is not a styrenic monomer in the strict sense. The methyl substitution on the side chain, rather than the aromatic ring, moderates its reactivity in polymerization. It is used as a specialty monomer in ABS resins, coatings, polyester resins, and hot-melt adhesives. As a copolymer in ABS and polystyrene, it increases the heat-distortion resistance of the product. In coatings and resins, it moderates reaction rates and improves clarity. Physical properties of a-methjistyrene [98-83-9] are shown in Table 12. 

Axial bonding of manganese-salen complexes to polystyrene containing phen-oxide or sulfonate groups yielded catalysts for the asymmetric epoxidation of styrene and styrene derivatives with NaClO/PPNO [35]. Catalyst performances were similar to the corresponding nonsupported systems and epoxide yields reached 93% with 70% ee using 1-phenylcyclohexene as substrate. Catalyst recyclability was investigated and the catalysts could be used up to three times in the epoxidation of ot-methylstyrene. 

After cleavage the reaction mass is a mixture of phenol, acetone, and a variety of other products such as cumylphenols, acetophenone, dimethyl-phenylcarbinol, Ot-methylstyrene, and hydroxyacetone. It may be neutralized with a sodium phenoxide solution (20) or other suitable base or ion-exchange resins. Process water may be added to facilitate removal of any inoiganic salts. The product may then go through a separation and a wash stage, or go direcdy to a distillation tower. 

The yield of acetone from the cumene/phenol process is believed to average 94%. By-products include significant amounts of Ot-methylstyrene [98-83-9] and acetophenone [98-86-2] as well as small amounts of hydroxyacetone [116-09-6] and mesityl oxide [141-79-7]. By-product yields vary with the producer. The Ot-methylstyrene maybe hydrogenated to cumene for recycle or recovered for monomer use. Yields of phenol and acetone decline by 3.5—5.5% when the Ot-methylstyrene is not recycled (21). 

Many substituents stabilize the monomer but have no appreciable effect on polymer stability, since resonance is only possible with the former. The net effect is to decrease the exothermicity of the polymerization. Thus hyperconjugation of alkyl groups with the C=C lowers AH for propylene and 1-butene polymerizations. Conjugation of the C=C with substituents such as the benzene ring (styrene and ot-methylstyrene), and alkene double bond (butadiene and isoprene), the carbonyl linkage (acrylic acid, methyl acrylate, methyl methacrylate), and the nitrile group (acrylonitrile) similarly leads to stabilization of the monomer and decreases enthalpies of polymerization. When the substituent is poorly conjugating as in vinyl acetate, the AH is close to the value for ethylene. 

Vapor-liquid equilibrium data of poly(ot- methylstyrene) in cyclohexane and a.-methylstyrene... 

Block copolymer of p-triphenylgermylstyrene with Ot-methylstyrene was produced in a similar manner to that of p-trimethyl silylstyrene and Ctf-methylstyrene. Gel-permeation chromatogram of the block copolymer shown in Fig. k had two peaks, suggesting that a part of carbanion was killed with impurity in the reaction mixture. 

Probably the most intensively studied derivative of styrene with regard to its polymerization behavior is a-methylstyrene. It is produced commercially by the dehydrogenation of isopropyl-benzene (cumene) and also as a by-product in the production of phenol and acetone by the cumene oxidation process. The polymerization characteristics of ot-methylstyrene are considerably dilferent from those of styrene. Whereas radical polymerization of the pure monomer proceeds very slowly and is therefore not a practical technique [196], both ionic and coordination-type polymerization can be used to prepare poly(a-methylstyrene) (PMS). 

The cationic polymerization of p-diisopropenylbenzene (DIPB) has been studied by Brunner et al. [305] and independently at the same time by Mitin and Glukhov [306]. Under conditions that favor dimerization of (ot-methylstyrene, Brunner et al. [305] could prepare soluble polymers, which contained predominantly polyindane structures, with catalysts such as BF3, SnCU, H2SO4, and H3PO4. They visualized the polymerization proceeding according to the following scheme ... 

Second virial coefficient of poly(ot-methylstyrene-b-styrene)... 

Cao X, Sipos L and Fhust R (2000) Polyisobutylene based thermoplastic elastomers VI. Poly(o(-methylstyrene-6-isobutylene-6-a-methylstyrene) triblock copolymers by coupling of living poly(ot-methylstyrene-6-isobutylene) diblock copolymers, Polym Bull 45 121-128. 

Thus, it is now possible to propose the structure of the unknown as the simple monomer ot-methylstyrene and that is the correct structure. 

Methacrylic acid-co-ot-methylstyrene Butyl methacrylate-co-4-vinylpyridine Single Tg FTIR I had 50.6 mol% methacrylic acid (MA) II had 1 or 26 mol% vinylpyridine (VP) 1131... 

Mikami reported a highly enantioselective carbonyl-ene reaction where a chiral titanium complex 11 prepared fiom enantiomerically pure binaphthol (BINOL) and TifO-i-PrjjBrj catalyzed a glyoxylate-ene reaction with ot-methylstyrene to give chiral homoallyl alcohol 12 with 94.6% ee [22]. In this reaction, a remarkable asymmetric amplification was observed and almost the same enantioselectivity (94.4% ee) was achieved by using chiral catalyst pvqrared... 

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