Styrene Substitution

Furthermore, for the first time this procedure has been extended to (i-ketoesters, although only an intramolecular reaction was feasible. However, with 5 mol% of Bi(OTf)3, the styrene-substituted ketoester 41 was converted into the 2,3-disubsti-tuted cyclohexanone 42 in 72% yield (Scheme 32). 

Mean-square unperturbed dimensions and dipole moments are calculated for propylene-vinyl chloride copolymers by means of RIS theory. The calculations indicate that for these chain molecules is much more sensitive to chemical sequence distribution than is 0, a conclusion in agreement with results of previous studies of ethylene-propylene copolymers and styrene-substituted styrene copolymers. In the case of propylene-vinyl chloride chains, both 0 and are most strongly dependent on chemical sequence distribution in the case of copolymers which are significantly syndiotactic in stereochemical structure. 

Borovik s group studied the concept of cobalt complexes in a polymeric matrix as sensor in more detail. Four-coordinated Co(II) metal centers were incorporated into a porous methacrylate network by copolymerization of a styrene-substituted cobalt(II)(salen) complex with ethylene glycol dimethacrylate (see Figure 3) [19]. These complexes were specifically studied for their sensor capacity for NO [20]. 

The ability to accept electrons from donors is particularly pronounced in acrylic acid derivatives [85] its alkyl esters [78, 87, 88], acrylonitrile [88], acrylamide, hydroxylacrylates [85], and further in styrenes substituted with an electronegative atom or group m-nitrostyrene, 2,6-dichlorostyrene [86], / -nitrostyrene [89] bicyclobutane-1-carbonitrile [89] lactones /J-propio-Iactone [85], sulfolactone vinyl ketones [87] unsaturated dicarboxylic acids and their derivatives diethyl fumarate, fumaronitrile [90], ROOC—N— N—COOR [86], cyclic anhydrides of diacids [91 ], particularly maleic anhydride [78, 92] ethylenes substituted with electronegative groups [93, 95]... 

The contribution of the homolytical substitution to the total sum of reactions occuning in free-radical polymerization in the presence of anthracene of its derivatives depends on the nature of the monomer and the anthracene-containing compound and on the polymerization conditions. It has been diown that the macroradicals of the methacrylic esters do not interact with anthracene under usual conditions On the other hand, in the polymerization of styrene, substitution with the formation of terminal LM of type II (Scheme 1) proceeds only if one or both meso-positions of the anthracene ring are free ... 

TEMPO, />substituted TEMPO based alkoxyamines 3, and compounds such as 4, 5, and 7 have been applied successfully for polymerizations of styrene, substituted styrenes, and 4-vinylpyridine, and some copolymerizations and block copolymerizations were reported. However, living and controlled radical polymerization of other monomers, especially acrylates, require the use of the more recently developed structures 6, 8, or 9. These also yield well-controlled and living block copolymers, but methacrylates have so far resisted all efforts to obtain large conversions. Undoubtedly, many failures are due to unfavorable rate constants or side reactions. 

In this study we show that it is possible to selectively epoxidize higher olefins to their corresponding epoxides if the olefins do not contain reactive allylic hydrogen atoms. Many olefins, including styrene, substituted butadienes, and norbornene have been selectively epoxidized. Because of the usefulness of 3,4-epoxy-1-butene as a new chemical intermediate, most of the data and discussion will involve the selective epoxidation of butadiene. The catalyst composition and overall kinetics of the reaction will be discussed in some detail. 

The first example of a catalytic LLC polymer network involved the cross-finked Hu phase of a styrene-substituted sodium carboxylate LLC monomer and added divinylbenzene cross-linker (Fig. 15). 

The reaction proceeds smoothly with styrene, -substituted styrenes, and /3-vinyl-naphthalene to give the corresponding ( )-vinylsilanes in 83-100% yield. However, isomerization of the double bond gives an allylsilane when a substrate having allylic proton(s) is employed ... 

In DMSO/water/trifluoroacetic acid, styrene, substituted styrenes, and some others are oxidized to the corresponding ketones with sole oxygen and... 

A typical result of allylsilylation is shown in Scheme 6.9. Styrene reacts with two aUyltrimethylsilanes to form the corresponding allylsilylated products in good yield. The reaction of styrenes substituted with halogens such as bromo, fluoro, and chloro at para positions proceeded with good to high yields. However, p-methoxystyrene did not work as a substrate. 

Lokaj and Bila (2003) studied the PV of EtOH-water mixtures through styrene-substituted V-phenylmaleimide copolymer membranes. The object was to estimate the effect of incorporated maleimide units on the PV properties on the polymeric membranes. For this, a number of copolymers of styrene with substituted V-phenylmaleimide were synthesized and their solutions in chloroform were used in the casting of homogeneous membranes. These membranes were characterized by the separation factor related to transported water and by the flux of the permeate. In contrast to the membranes made from copolymers of styrene with V-phenyhnaleimide, the separation factor of the membranes containing substituted V-phenyhnaleimide increased with increasing amount of EtOH in the feed solution. 

Lokaj, J. and Bila, J. 2003. Pervaporation of ethanol-water mixtnres through styrene-substituted N-phenyhnaleimide copolymer membranes. 46(11) ... 

In most cases, group R (Scheme 4) depicts an electronegative substituent in such olefins as styrene, substituted styrenes, trifluoropropene, and vinyl trisub-stituted silanes. Complexes of iron and cobalt triads have appeared extremely favorable catalysts of the dehydrogenative silylation, but Ni, Pd, and Pt complexes have also recently been reported as active catalysts of these olefins conversions [for reviews see References (3,11,13,18). 

The organic portion of the composihon constitutes an organic polymeric binder containing a copolymer or interpolymer of an alkyl acrylate or alkyl methacrylate, styrene, substituted styrene, or combinations of these... 

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