Phosphonium salts styrenes

Bromo-j3-nitrostyrene and triphenylphosphine in dry benzene gave the phosphonium bromide (47). Using methanol as the solvent, the rearranged product (48) was formed, possibly via an azirine intermediate. Substituted -bromo-/3-nitrostyrenes yield the phosphoranes (49) and a phosphonium salt. When the aryl group is electron-donating, the reaction follows a different course to form the styrene (50) by initial attack of the phosphine on halogen. 

In the phosphonium salt synthesis, the addition reaction of tertiary phosphines to activated alkenes has been reported (Scheme 3). PPh3 is added to electron-deficient alkenes such as enones or enals at the p-position in the presence of acids.4 The reaction of styrenes with phosphine has recently been reported by Okuma, which gave Markovnikov adducts.5 Although no catalyzed reactions of... 

Ferrocenyl ligands, via zinc reagents, 9, 120 Ferrocenylmethyl phosphonium salts, with gold(I), 2, 274 Ferrocenylmonophosphine, in styrene asymmetric hydrosilylation, 10, 817 Ferrocenyl oxazolines, synthesis, 6, 202 Ferrocenylphosphines with chromium carbonyls, 5, 219 in 1,3-diene asymmetric hydrosilylation, 10, 824-826 preparation, 6, 197 various complexes, 6, 201 Ferrocenylselenolates, preparation, 6, 188 Ferrocenyl-substituted anthracenes, preparation, 6, 189 Ferrocenyl terpyridyl compounds, phenyl-spaced, preparation 6, 188 Ferrocifens... 

Ketones. Condensations between the phosphonium salt (23) and alkyl aryl ketones in the presence of methylsulphinylmethanide ion lead to mixtures of (Z)-stilbenes and ( )-styrenes in stereospecific reactions resulting from dichotomous ylide formation (Scheme 2). The authors have shown that this unusual behaviour is due to the... 

A fine balance between steric and electronic effects in attempted olefin synthesis in protic solvents has been revealed in experiments involving furyl-and pyrrolyl-phosphonium salts. Thus although the salt (2 R = Ph) gave a high yield of styrene with benzaldehyde in ethanolic ethoxide solution, the t-butyl salt (2 R = Bu ) under the same conditions gave the styrylphosphine... 

Phase-transfer catalysts are used to facilitate reactions between reagents that are in two different phases (e.g., 1-bromooctane in toluene with aqueous potassium iodide to form 1-iodooctane). They are usually quaternary ammonium or phosphonium salts or crown ethers. They can complicate the workup of the reaction and may be difficult to recover for reuse. When they are insoluble polymeric ones, workup and recycle can be done by simple filtration.192 The process is called triphase catalysis. In favorable cases, their activity can be comparable with that of their lower molecular weight analogues. They are often based on cross-linked polystyrene, for which spacers between the aromatic ring and the quaternary onium salt can increase activity two- to fourfold. Copolymerization of 4-vinylben-zyl chloride with styrene or N, N- d i m e Ihy I a c ry I a m i d e, followed by treatment with tri-/ -butylphosphine produced catalysts that were used in the reaction of benzyl chloride with solid potassium acetate (5.43).193... 

Indoles and Carbazoles. - Formation. 2-Arylindoles (132) are formed by intramolecular Wittig reaction of the phosphonium salts (131). The hydroxamic acids PhN(OH)COCH2COR (R = alkyl or aryl) cyclize in boiling toluene to mixtures of indoles (133) and 3-isoxazolones (134). Irradiation of a solution of o-iodoaniline and the potassium enolate of acetone affords 2-methylindole. The enamino-ketone (135) cyclizes photochemically to 1,2-dimethylindole (136) with elimination of acetaldehyde/ The styrene derivative (137), obtained by the action of Meerwein s acetal, Me2NCH(OMe)2, on o-nitrotoluene, yields 1-hydroxyindole on treatment with zinc/ Azidobenzocyclobutanes (138 R = Me, Ph, or CH2Ph) are converted into indoles (133) by the action of concentrated sulphuric acid/ ... 

Sulfonium88 and phosphonium salts can be converted into olefins by methods analogous to Hofmann degradation of quaternary ammonium salts. For example, substituted styrenes are obtained in good yield by the slightly exothermic reaction of appropriate sulfonium bromides with 10% sodium hydroxide solution.89... 

Synthesis. Polymers containing the vinyl-benzyl phosphonium unit can be made by either direct synthesis of the monomers and subsequent polymerization or phosphonation of chloromethyl styrene containing polymers. The latter is preferred due to the difficulty of obtaining the vinyl benzyl phosphonium monomer in good yield and purity without spontaneous polymerization. In either case, synthesis of elastomers containing quaternary phosphonium salts have not been reported to date. 

Analysis of FTIR spectra of the ionomer(Figures 3 and 4) was also informative about the structure. It was reported previously that IR absorption bands at 1893 cm" and 1905 cm"l were characteristics of 4-methylstyrene (of > 50) and 4-bromomethyl styrene (of Exxpro elastomer, Figure 5). Such absorption bands were not found in the FTIR spectra of the above ionomers. However, new absorption peaks, characteristics of the quaternary phosphonium salts, at 1580, 1100, 100, 670-730 cm" were observed. The presence of both phosphorous and boron in the above ionomers was also confirmed in terms of the elemental analysis data, collected from the inductively coupled plasma/atomic emission spectroscopy(ICP/AES) technique. These results were in good agreement with the expected convertion of the respective phosphonium salts. 

An intramolecular Wittig reaction of the phosphonium salt PhsP—CH2-CH2CH20C0Ph Br yields the dihydrofuran (15). Compound (16) is formed from styrene and acetone in the presence of lead dioxide by a free-radical mechanism. The A -dihydrofuran (17) is produced by the action of silver fluoroborate on the allenic alcohol HOCH2CH=C=CMeBu another compound of this type, namely (18), is the product of the reaction of the sulphurane H2C=SMe2 with salicylideneacetone. ... 

By emulsion polymerization of styrene with chloromethylated styrene in the presence of divinylbenzene and hexadecyltrimethylammonium bromide as a surfactant, latex particles of the copolymer were synthesized with a diameter of 0.08-0.2 m [67,68]. The copolymer was transformed directly to phosphonium salts by boiling the emulsion with tributylphosphine for 24 h. The stirring rate over 510-670 rpm did not affect the rate constants of catalyzed, interfacial transfer reactions of the aqueous solution of sodium cyanide with 1-bromooctane at 90 °C and with benzyl bromide at 80 °C in toluene in the presence of the above catalysts. The catalyst activity increased with an increase in the latex particle size. 

A concise synthesis of substituted stUbenes from propargylic phosphonium salts by a cobalt-catalyzed Diels-Alder/Wittig olefination reaction has been described (Figure 1.4) [37]. It was shown that the cobalt(I)Diels-Alder reaction of propargylic phosphonium salts and alkyne-fimctionalized phosphonium salts with 1,3-dienes led to dihydroaromatic phosphonium salt intermediates that were directly used in a one-pot Wittig-type olefination reaction with aldehydes. Subsequent oxidation led to styrene- and stUbene-type products with the formation of three new carbon-carbon bonds. The reaction gives predominantly the Econfigured products. 

At a relatively high reaction temperature (150°C), Reetz et al. also accomplished the Mizoroki-Heck reaction of chlorobenzene with styrene in the presence of Pd(OAc)2 and phosphonium salt PI14PCI [23aj. Again, the high catalytic activity was ascribed to the presence of nanosized palladium colloids, which are beheved to be stabilized by the phosphonium salt... 

Chemistry. They are made by reaction of methaciylic acid with epoxy resins (Fig. 3.16). The reaction is catalyzed by benzyl trunethyl ammonium chloride, or oxo-nium or phosphonium salts (Table 3.25). Like polyesters, they are dissolved in liquid styrene monomer and stabilized by hydroquinone. And, like polyesters, they are cured by organic peroxides activators, at room temperature to 150°C. 

On the other hand Abdallah et al. [22] showed that bentonites modified by alkyl and aryl based phosphonium salts in poly(ethylene terephthalate) exhibited better dispersion than those unmodified. In 2010 Gu [23] showed that montmorillonite modified Octadecylammonium improves dispersion in namral rubber/butadiene rubber nanocomposites. Have also been studied in terms of particle size of styrene-butadiene mbber (SBR) nanocomposites showed remarkable improvement in thermal stability their compared to that of the pure SBR. Was also demonstrated that the increase in particle size is not beneficial in improving the thermal stability [5]. 

Since the above phase transfer catalysed reactions worked particularly well with phosphonium salts prepared from benzyl halides, it was considered of interest to investigate reactions using phosphonium salts (4) prepared from chlorome thy late d polystyrenes, that is reactions where the supported species was the alkyl halide (see Scheme 2). Both linear and crosslinked chloromethylated polystyrenes reacted smoothly with triphenylphosphine to give polymers with residues (4). ° An alternative way of preparing the linear polymer is by copolymerisation of styrene and the salt (5). When the salts (4) were treated with various aldehydes in methylene chloride and... 

A similar approach has been carried out by Kim et al. (62) who disclosed the use of sulfbnated styrene-divinylbenzene resins plus a tris(dialkyla-minophosphine) to obtain a phosphonium attached salt which can exchange triphenylphosphine ligands in [Ru(CO)3(PPh3)2] or [RUCI2-... 

I.I. Abu-abdoun and A. Aale, Cationic photopolymerization of styrene by phosphonium and arsonium salts. J. Macromol. Sci. Pure Appl. Chem. 1993, A30, 327-336. 

The spectra of highly coloured phosphoniovinamidinium salts (68 Y or Z = PhsP+) have been recorded. The energy levels and conformations of an extensive series of phosphonium ylides have been deduced from their u.v. spectra. In addition there have been studies of phosphonium polyiodides, phosphinyl styrenes, and solvent effects on the spectra of thioamides (69). ... 

A common group of cationic antistats is alkyl quaternary ammonium salts. These are mostly employed in polar substrates such as PVC and in styrenic polymers. Other types include alkyl phosphonium and alkyl sulfonium salts. Flexible PVC may contain up to 7% of these antistatics for nonfood uses, as they have not been approved by the FDA. Sodium alkyl sulfonates, similar to common detergents, have gained wide acceptance as anionic antistatic agents, and are used in PVC and styrenic polymers. Other anionic antistats include alkyl phosphonic, dithiocarba-mic, and carboxylic acids. 

Cationic antistats are generally long-chain alkyl quaternary ammonium, phosphonium, or sulfonium salts with, for example, chloride counterions. They perform best in polar substrates, such as rigid PVC and styrenics, but normally have an adverse effect on the resin s thermal stability. These antistat products are usually not approved for use in food-contact applications. Furthermore, antistatic effects comparable to those obtained from other internal antistats such as ethoxylated amines are only achieved with significantly higher levels, typically, five- to tenfold. 

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