Fluoroacrylates

Cosolvents ana Surfactants Many nonvolatile polar substances cannot be dissolved at moderate temperatures in nonpolar fluids such as CO9. Cosolvents (also called entrainers, modifiers, moderators) such as alcohols and acetone have been added to fluids to raise the solvent strength. The addition of only 2 mol % of the complexing agent tri-/i-butyl phosphate (TBP) to CO9 increases the solubility ofnydro-quinone by a factor of 250 due to Lewis acid-base interactions. Veiy recently, surfac tants have been used to form reverse micelles, microemulsions, and polymeric latexes in SCFs including CO9. These organized molecular assemblies can dissolve hydrophilic solutes and ionic species such as amino acids and even proteins. Examples of surfactant tails which interact favorably with CO9 include fluoroethers, fluoroacrylates, fluoroalkanes, propylene oxides, and siloxanes. 

In the early 1950s the fluoroacrylate polymers Poly-lF4 and Poly-2F4 (known initially as PolyFBA) and PolyFMFPA) were introduced. These materials had the structures given in Figure 13.7. These materials are also no longer of eommercial significance. 

The addition of nucleophiles to cyclic fluoroolefins has been reviewed by Park et al. [2 ]. The reaction with alcohols proceeds by addition-elimination to yield the cyclic vinylic ether, as illustrated by tlie reaction of l,2-dichloro-3,3-di-fluorocyclopropene Further reaction results in cyclopropane ring opening at the bond opposite the difluoromethylene carbon to give preferentially the methyl and ortho esters of (Z)-3-chloro-2-fluoroacrylic acid and a small amount of dimethyl malonate [29] (equation 8). 

Single vinylic fluorine substituents absorb over quite a wide range of chemical shifts, with fluoroallene at the high field end (-169 ppm) and P-fluoroacrylate derivatives at the low field end (-75 ppm) (Scheme 3.36). 

The fluoroacrylic polymers are high-modulus, low-elongation plastics, which are brittle in the sense that all thermosetting polymers are brittle. However, they are tough, rugged materials not easily damaged by impact or mechanical abuse. 

Taguchi and coworkers175 studied the Lewis acid catalyzed asymmetric Diels-Alder reactions of chiral 2-fluoroacrylic acid derivatives with isoprene and cyclopentadiene. When a chiral l,3-oxazolidin-2-one and diethylaluminum chloride were used as the chiral auxiliary and the Lewis acid catalyst, respectively, a de of 90% was observed for the reaction with isoprene. The reaction with cyclopentadiene afforded a 1 1 mixture of endo and exo isomers with de values of 95% and 96%, respectively. The endo/exo selectivity was improved by using 8-phenylmenthol as the chiral auxiliary. Thus, the reaction... 

The Diels-Alder reaction between a 2-fluoroacrylic acid derivative of 8-phenyl-menthol (83) and cyclopentadiene shows high exo- and jr-diastereofacial selectivity (Scheme 30). The C(2) of endocyclic cross-conjugated 2-(acylamino)-l,3-dienes exerts excellent diastereofacial control on the Diels-Alder addition with electron-deficient dienophiles to produce octahydroquinolines. ... 

With the ready availability of 2-fluoro-allylic halides and a-fluoroacrylic acid derivatives, incorporation of a pendant fluorovinyl unit is easier than ever. The utility of these products is markedly enhanced by the reactivity of the fluorovinyl unit in olefin metathesis reactions. Some success has been found in cyclization reactions as shown below [83] (Scheme 36). 

CljCOaCHs - poly(methyl alpha-chloroacrylate) (PMCA) F,C02CH3 - poly(methyl alpha-fluoroacrylate) (PMFA)... 

Supercritical CO2 at temperatures of 31-50 °C and pressures of about 10 MPa is now widely used as a nontoxic extractant of excess fats from foodstuffs and in decaffeinating coffee, but its largest scale future use is likely to be the enhancement of recovery of oil that cannot be extracted from wells by conventional techniques. Supercritical CO2 is finding increasing favor as a solvent for chemical syntheses, for example, in the radical-promoted polymerization of fluoroacrylic monomers in homogeneous solution, for which ozone layer-destroying chlorofluorocarbons had been the only effective solvents previously.210... 

Fluoroacrylic Esters and Related Monomers Preparation and Use as Synthons Wakselman, C. Macromol. Symp. 1994. 82, 77-87. 

Four fluorinated acrylates are presented in Table 4 [66, 67, 68, 69] to supplement the vmyl fluoride data Perfluoroacrylic acid [70] and methyl per-fluoroacrylate [69, 70] are both reported m the literature. The cis and trans isomers of fluoroethylenes are readily distinguished by the magnitude of their coupbng constants, with 3J trans typically more than 3 tunes the magnitude of 3J as... 

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