Chlorides vinyl, from ketones

Random copolymers of vinyl chloride and other monomers are important commercially. Most of these materials are produced by suspension or emulsion polymerization using free-radical initiators. Important producers for vinyl chloride—vinyUdene chloride copolymers include Borden, Inc. and Dow. These copolymers are used in specialized coatings appHcations because of their enhanced solubiUty and as extender resins in plastisols where rapid fusion is required (72). Another important class of materials are the vinyl chloride—vinyl acetate copolymers. Principal producers include Borden Chemicals Plastics, B. F. Goodrich Chemical, and Union Carbide. The copolymerization of vinyl chloride with vinyl acetate yields a material with improved processabihty compared with vinyl chloride homopolymer. However, the physical and chemical properties of the copolymers are different from those of the homopolymer PVC. Generally, as the vinyl acetate content increases, the resin solubiUty in ketone and ester solvents and its susceptibiUty to chemical attack increase, the resin viscosity and heat distortion temperature decrease, and the tensile strength and flexibiUty increase slightly. 

If prepared from vinyl chloride, this unstable ketone will decompose almost explosively within one day, apparently owing to the presence of some c/s-isomer. 

Nitrones (268), derived from ketones, undergo a Beckmann-like rearrangement when treated with tosyl chloride in pyridine. Unlike the Beckmann rearrangement, however, the reaction is independent of the nitrone configuration, and shows a preference for vinyl migration. The consequence, for a 4-en-3-one derivative, is the formation of the unusual enamine-lactam (270). The hydroxyl-amino-O-tosylate derivative (269) is considered a likely intermediate (see also Part II, Chap. 2, p. 353). 

A variety of pyridine ring syntheses stem from Vilsmeier formylation of alkenes, enamines, vinyl ethers, ketones, and related systems followed by a separate cyclization of the derived salts with ammonium chloride or acetate.49... 

If the electrophile is a vinyl triflate, it is essential to add LiCl to the reaction so that the chloride may displace triflate from the palladium o-complex. Transmetallation takes place with chloride on palladium but not with triflate. This famous example illustrates the similar regioselectivity of enol triflate formation from ketones to that of silyl enol ether formation discussed in chapter 3. Kinetic conditions give the less 198 and thermodynamic conditions the more highly substituted 195 triflate. 

The cleavage of carbon-oxygen bonds from alkenyl or aryl phosphates can be accomplished under reductive conditions with a low valent metal. As vinyl phosphates can be formed readily from ketones, this procedure provides a method to convert a ketone to an alkene. For example, the alkenyl phosphate 74 was prepared by trapping the enolate formed on reduction of the enone 73 and was converted into the alkene 75 (7.55). The chemistry therefore provides a method to prepare structurally specihc alkenes. Low-valent titanium (prepared for example by reduction of titanium(III) chloride with potassium metal) is a convenient alternative to lithium or sodium in liquid ammonia or an amine for the reductive cleavage of alkenyl or aryl phosphates. 

Of critical importance, analysis of poly(methyl methacrylate) (PMMA) showed that at a saturation temperature, T, of 40°C, a saturation pressure, P%, of 1,500 psig (at these conditions, carbon dioxide is considered a supercritical fluid), and a saturation time, ts, of 24 h, a 1 mm thick disk absorbed 16.4 wt% carbon dioxide. Additionally, at a foaming temperature, Tf, of 120°C and a foaming time, tf, of 1 min, PMMA had a stable volumetric expansion ratio of 20. Other polymers also absorbed significant quantities of carbon dioxide, such as polystyrene (PS) and poly(vinylidene chloride-co-acrylonitrile) (P(VDC-AN)), which absorbed 8.9 and 2 wt% carbon dioxide, respectively, yet the stable foams that were formed had expansion ratios of less than 2 at the same conditions used to form the PMMA samples. Another polymer poly(vinyl methyl ketone) (PVMK) achieved an expansion ratio of 20. However, the foams were unstable, readily collapsed, and exhibited large voids ( 5 mm diameter), which are inconsistent with microcellular foams. The fact that PVMK readily collapsed after the foaming process made it difficult to determine the concentration of carbon dioxide in the sample. These results led to the eventual incorporation of the MMA monomer into the polymer formulation from the standpoint of carbon dioxide-induced microcellular foamability. 

The existence of an absorption at around 1430-1420 cm indicates the presence of an a-methylene (sometimes known as an active methylene), adjacent to the ester or ketone carbonyl. This, in conjunction with the presence of a normal aliphatic methylene sequence (1450-1470 cm ) differentiates the vinyl polymers, such as polyvinyl alcohol (PVA) and polyvinyl chloride (PVC), from compounds such as PMA and PMMA. Since this step may be confusing to the reader, it is suggested that attention is paid to the assignments for vinyl acetate-type and acrylate-type polymers. 

The most useful synthetic methods are those based on the transfer of unsaturated residues such as allyl, vinyl, propargyl, acetylene and allene groups. It has been found, however, that saturated alkyl groups are also capable of being transfered from a silicon atom to a carbon atom. It was found at first [572] that trimethylsilylacety-lenes reacted with acyl halides in the presence of aluminium chloride to give ketones of the acetylene series (Eq. 4.33) ... 

Allylic thiocarbamates (145) are available from ketones by sequential condensation with vinyl-lithium species and dimethylthiocarbamoyl chloride followed by a [3,3] sigmatropic rearrangement. It has now been shown that these can be used as precursors to a,jS-unsaturated esters by bis-sulphenylation and mercury(ii)-promoted hydrolysis (Scheme 39). Only the B-isomers are produced when the final product (146) is unsubstituted i.e. = H) or carries an a-methyl... 

Su and co-workers reported an interesting Sc-catalyzed reaction of ketones with benzoyl chloride to produce aryl-Z-vinyl chlorides (Fig. 34) [73]. While Sc(OTf)3 activated the carbonyls towards attack by the acid chloride, bis(trichloromethyl) carbonate (triphosgene) regenerated the benzoic chloride catalyst from the benzoic acid side product. All the products in this report were obtained as pure Z-isomer. A transition state model was proposed to account for the stereoselectivity of the system, in which cA-elimination took place through a six-membered chair transition state with the substituents on the substrate residing at the equatorial position. 

Ketones can also be used in this transformation, but sometimes enolizable ketones lead to the formation of the vinyl chloride derived from the enol. This is usually more of a problem for six-membered ring ketones than for five-membered ring ketones. Cyclopentanone yields predominantly the 1,1-dichloroalkene (eq 33), while cyclohexanone provides mainly the vinyl chloride (eq 34). ... 

The alcohols, proprietary denatured ethyl alcohol and isopropyl alcohol, are commonly used for E-type inks. Many E-type inks benefit from the addition of small amounts of ethyl acetate, MEK, or normal propyl acetate to the solvent blends. Aromatic hydrocarbon solvents are used for M-type inks. Polystyrene resins are used to reduce the cost of top lacquers. T-type inks are also reduced with aromatic hydrocarbons. Acryflc resins are used to achieve specific properties for V-type inks. Vehicles containing vinyl chloride and vinyl acetate copolymer resins make up the vinyl ink category. Ketones are commonly used solvents for these inks. 

Vinyllithium [917-57-7] can be formed direcdy from vinyl chloride by means of a lithium [7439-93-2] dispersion containing 2 wt % sodium [7440-23-5] at 0—10°C. This compound is a reactive intermediate for the formation of vinyl alcohols from aldehydes, vinyl ketones from organic acids, vinyl sulfides from disulfides, and monosubstituted alkenes from organic halides. It can also be converted to vinylcopper [37616-22-1] or divinylcopper lithium [22903-99-7], which can then be used to introduce a vinyl group stereoselectively into a variety of a, P-unsaturated systems (26), or simply add a vinyl group to other a, P-unsaturated compounds to give y, 5-unsaturated compounds. Vinyllithium reagents can also be converted to secondary alcohols with trialkylb o r ane s. 

As with poly(vinyl alcohol), poly(vinyl cinnamate) is prepared by chemical modification of another polymer rather than from monomer . One process is to treat poly(vinyl alcohol) with cinnamoyl chloride and pyridine but this is rather slow. Use of the Schotten Baumann reaction will, however, allow esterification to proceed at a reasonable rate. In one example poly(vinyl alcohol) of degree of polymerisation 1400 and degree of saponification of 95% was dissolved in water. To this was added a concentrated potassium hydroxide solution and then cinnamoyl chloride in methyl ethyl ketone. The product was, in effect a vinyl alcohol-vinyl cinnamate copolymer Figure 14.8)... 

Copolymers of vinyl chloride, containing 5 to 40 percent vinyl acetate made by the inclusion of vinyl acetate in the polymerization process, have lower softening points and flow more easily than polyvinyl chloride. They are soluble in ketones, such as acetone, and certain esters for making film from solutions. They are used for phonograph records, rigid clear sheeting, and molding pov... 

Epoxidation of aldehydes and ketones is the most profound utility of the Corey-Chaykovsky reaction. As noted in section 1.1.1, for an a,P-unsaturated carbonyl compound, 1 adds preferentially to the olefin to provide the cyclopropane derivative. On the other hand, the more reactive 2 generally undergoes the methylene transfer to the carbonyl, giving rise to the corresponding epoxide. For instance, treatment of P-ionone (26) with 2, derived from trimethylsulfonium chloride and NaOH in the presence of a phase-transfer catalyst Et4BnNCl, gave rise to vinyl epoxide 27 exclusively. ... 

Methyl phenyl sulfide, see Thioanisole Methyl phenyl sulfoxide, 46, 78 from methylsulfinyl chloride and benzene with anhydrous alumi num chloride, 46, 80 Methyl vinyl ketone, reaction with 1-morpholino 1 cyclohexene, 45,... 

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