Styrenes fluoro

Figure 5 is an ORTEP computer plot of the first 50 backbone carbons in a typical chain. Only the fluorine atoms of the sidechains are shown. The various hard sphere exclusions conspire dramatically to keep the fluorines well separated and the chain highly extended even without introducing any external perturbations. The characteristic ratio from the computer calculations is about 11.6 from data for poly(p-chlorostyrene), CR = I l.l, poly(p-bromostyrene), CR = 12.3, and poly(styrene), CR = 10.3 (all in toluene at 30°C), we expect the experimental value for the fluoro-polymer to be in the range of 10 to 12. 

However, one should not forget that apart from the complexity of the synthesis fluoropolymers are very expensive. For example, the price of fluoro-rubber is more than 30-fold that of an ordinary rubber such as butadiene-styrene (SBR) or ethylene-propylene (EPDM). Cost was one of the factors that gave impetus to research polymer surface fluorination, with the object of imparting the properties of fluoropolymers to the surfaces of less expensive polymers without changing their bulk properties. 

Tanner et al. (58) investigated the asymmetric aziridination of styrene using bis(aziridines) such as 85. Low induction is observed with these ligands, Eq. 64. A significant electronic effect was noted with the p-fluoro-phenyl substituted bis(az-iridine) 85c (59). A binaphthyl-derived diamine was used as a ligand for the copper-catalyzed aziridination of dihydronaphthalene (81). The product was formed in 21% ee and 40% yield, Eq. 65. Other structurally related ligands proved to be less selective in this reaction. 

Scheme 6.7S Prod ucts of the cycloadditions of 1 -oxa-2,3-cyclohexadiene (351), liberated from exo-6-bromo-endo-6-fluoro-2-oxabicyclo[3.1.0]-hexane (354), to styrenes, 1,3-butadiene, isoprene, 2,3-dimethyl-l, 3-butadiene,...

Scheme 6.83 Generation of l-thia-2,3-cyclohexadiene (406) from exo-6-bromo-endo-6-fluoro-2-thiabicyclo[3.1. OJhexane (405) by methyllithium and trapping of406 by styrene and 1,3-butadiene.

N-Methylpyrrolidinone 2-Pyrrolidinone, 1-methyl- (8,9) (872-50-4) p-Fluorostyrene Styrene, p-fluoro- (8) Benzene, 1-ethenyl-4-fluoro- (9) (405-99-2)... 

The reaction w ith styrene in acetonitrile, on the other hand, gives two vicinal fluoro sulfates 4 and 5 with preference for mn/ -Markovnikov regioselectivity, and svn addition with other alkenes.11... 

Treatment of epoxides with DAST results in the formation ofgem-difluorides, vicinal difluorides and bis(2-fluoroalkyl) ethers.54 The product distribution is dependent upon the nature of the epoxide. For example, cyclohexene oxide (1) gives a mixture of eis-difluorides and bis(a-fluoro) ethers, whilst styrene oxide (2) affords a mixture of difluorophenylethanes. This reaction is of little practical use due to the problems associated with the isolation of pure products. 

Reaction of AT-fluorobis(trifluoromethylsulfonyl)amine (Id) with alkenes gives various products, depending on the reaction conditions and the structure of the substrate. In solvents of higher nucleophilicity such as water, acetic acid, aqueous hydrochloric acid, and 70 % hydrogen fluoride/pyridine, a-fluorohydrins or their acetates, a-chloro-fl-fluoroalkanes or a,/ -difluoroal-kanes, e.g. 14. are obtained.146 Reaction of styrene and ( >l-phenylpropene with Id in dich-loromethane/acetic acid gives l-acetoxy-2-fluoro-l-phenylethane and -propane, in 92 and 99 % yield, respectively, the latter product in a ratio (erythrojthreo) 1 l.146... 

The formation of l-fluoro-2-iodo-l-phenylethane (8) from styrene and KH4F5 in the pressure of (V-iodosuccinimide in 80% yield is described in a patent.164... 

As to the system styrene/o-fluoro styrene (case a) a complete isomorphism is observed within the whole range of compositions. The macromolecules assume the conformation of a 3/1 helix, characteristic... 

The system consisting of copolymers of styrene and />-fluoro styrene (case b), instead, is characterized by isodimorphism. For the whole range of copolymer compositions the system exhibits crystallinity. The crystal structure is that of the homopolymer deriving from the predominant comonomer. Up to >-fluoro styrene, contents of about 50% by moles the copolymers crystallize in the threefold helix structure of iso-... 

Ethylene-propylene rubber Fluoro-rubber Hypalon Natural rubber Neoprene rubber Nitrile rubber Polysulphide rubber Polyurethane rubber Silicone rubber Styrene-butadiene rubber (SBR)... 

Anilkumar, R. Burton, D. J. A highly effrcient room temperature non-organometallic route for the synthesis of r/./f/j-tri fluoro styrenes by dehydrohalogenation. Tetrahedron Lett. 2003, 44, 6661-6664. 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

In addition, Kennedy and Hongu [129] have prepared amphiphilic diblock cooligomers from the condensation of a-methoxy-co-hydroxy polyoxyethylene with isocyanato-terminated polyisobutylene. In the same way, from a,codiisocyanate styrenic telomer 29, a Japanese team [130] has prepared PFA-h-PS-h-PFA and PHEA-h-PS-h-PHEA triblock copolymers (where FA and HEA represents fluoro acrylate and 2-hydroxy ethyl acrylate, respectively), as follows ... 

Some half sandwich titanium compounds with cyclopentadienyl ligands have proven to be most active, but soluble tetraethyoxytitanium also shows a certain amount of activity. In contrast to olefin polymerization, titanocenes are more active than zirconocenes and fluoro ligands are better than chloro ligands. Table 24 [207] compares some catalysts for the polymerization of styrene. 

The only reported generation of fluoroiodocarbene involves the treatment of fluoro-diiodomethanc with sodium hydroxide in a two-phase system with benzyltriethylammonium chloride as a phase-transfer agent. Although a good yield of the fluoroiodocyclopropanc is obtained when fluoroiodocarbene is generated in the presence of styrene, with more sterically erowded substrates and unconjugated alkcnes the yields are low. 

Estane 5702-Fl Viton A BDNPA-F Polyurethane solution system Vinylidine fluoride/hexafluoropropylene copolymer, 60/40 wt % Bis(2,2-dinitropropyl)acetal/bis(2,2-dinitropropyl) formal, 50/50 wt % Tris- -chlorethylphosphate Chlorotrifluoroethylene/vinylidine fluoride copolymer, 3 1 Vinyl chloride/chlorotrifluoroethylene copolymer, 1.5 1 Styrene polymer, 100% Di(2-ethylhexyl)phthalate Bis(2-fluoro-2,2-dinitroethyl)foimal... 

When fran5-)8-[fluoro(dimethyl)silyl]styrene was allowed to react with iodobenzene, a small amount of 1,1-diphenylethene (cine substitution product) was produced in addition to the expected tra/ii -stilbene (ipso substitution product) [Eq.(12)]. 

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