Sulfur dioxide, copolymerization with

We have prepared a series of copolymers under the conditions shown in Table 2. The monomer feed was always a 50 50 ratio of chloroprene to sulfur dioxide. Copolymerizations were carried out in bulk at temperatures from -78 to 100°. Initiators were tertiary butyl hydroperoxide at low temperatures, where it forms a redox system with the SO2 and is more effective than one might otherwise expect. Silver nitrate was used at 0° and 25°, azoiso-butyronitrile at 40° and 60°, and azodicyclohexanecarbonitrile... 

Butene—Sulfur Dioxide Copolymerization. Polybutene sulfones are well known. Copolymerization of 1-butene with sulfur dioxide is characterized by certain features ... 

In 1898 Solomina [1] reported that sulfur dioxide reacted with allyl alcohol, allyl methyl ether, and allyl ethyl ether [1]. Solomina reported that carboxyl, halide, and ester groups inhibited the reaction [1]. In 1935 Ryden and Marvel [26] reported that sulfur dioxide did not copolymerize with allyl cyanide or 2-allyl-/i-cresol when peroxide-paraldehyde was used but did polymerize when ascaridole was added [62]. In a later publication Kharasch and Steinfeld reported that allyl chloride copolymerized with sulfur dioxide in the presence of ascaridole and aqueous hydrochloric acid [63]. 

Here, a third monomer can be included to interpolymerize with the complex that acts as a unit. The product is a terpolymer. A diradical intermediate was also postulated in sulfur dioxide copolymerizations and terpolymerizations with bicycloheptene and other third monomers. These third monomers enter the copolymer chain as block segments, while the donor-acceptor pairs enter the chains in a one-to-one molar ratio. This one-to-one molar ratio of the pairs is maintained, regardless of the overall nature of the monomer mixtures. 

Butadiene is easily polymerized and copolymerized with other monomers. It reacts by addition to other reagents such as chlorine, hydrocyanic acid, and sulfur dioxide, producing chemicals of great commercial value. 

The free-radical reaction may be equally initiated by photoactivated sulfur dioxide (3S02)442 (equation 79). On the other hand, polysulfones are obtained by radical copolymerization of appropriate olefins with sulfur dioxide443-449, and similarly, uptake of sulfur dioxide by a radical-pair formed by nitrogen extrusion from an azo compound yields the corresponding sulfone450 (equation 80). Correspondingly, alkylbenzenes, dibenzoyl peroxide, and sulfur dioxide yield sulfones under thermal conditions451... 

Copolymers of carbon monoxide, carbon dioxide, sulfur dioxide or carbon disulfide are frequently formed in combination with oxiranes, thiiranes or aziridines. Copolymerization of carbon monoxide and ethylenimine was carried out under radiation and the formation of 3-nylon was observed238. ... 

It has been shown by Barb and by Dainton and Ivin that a 1 1 complex formed from the unsaturated monomer (n-butene or styrene) and sulfur dioxide, and not the latter alone, figures as the comonomer reactant in vinyl monomer-sulfur dioxide polymerizations. Thus the copolymer composition may be interpreted by assuming that this complex copolymerizes with the olefin, or unsaturated monomer. The copolymerization of ethylene and carbon monoxide may similarly involve a 1 1 complex (Barb, 1953). 

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

Sulfur dioxide does not homopolymerize but does participate in a rather wide variety of free radical copolymerizations with unsaturated monomers. The resulting polysulfones have been known for quite a long time. Solonina ( f ) obtained a white solid from the reaction of SO2 with allyl ethers in 1898, but such products were not recognized as copolymers until the work of Marvel and Staudinger in the 1930 s. 

A variety of reactants—including sulfur dioxide, carhon monoxide, and oxygen, which do not homopolymerize—undergo radical copolymerization with alkenes to form polymeric sul-fones [Bae et al., 1988 Cais and O Donnell, 1976 Dainton and Ivin, 1958 Floijanczyk et al., 1987 Soares, 1997], ketones [Sommazzi and Garhassi, 1997 Starkweather, 1987, and peroxides [Cais and Bovey, 1977 Mukundan and Kishore, 1987 Nukui et al., 1982] ... 

Some copolymerizations have been studied where one of the reactants is a compound not usually considered as a monomer. These include copolymerizations of epoxides and higher cyclic ethers with carbon dioxide, episulhdes with carbon dioxide and carbon disulhde, and epoxides with sulfur dioxide [Aida et al., 1986 Baran et al., 1984 Chisholm et al., 2002 Inoue and Aida, 1989 Soga et al., 1977]. The copolymers are reported to be either 1 1 alternating copolymers or contain 1 1 alternating sequences together with blocks of the cyclic monomer. 

Another group of potentially large volume plastics that is under development are the polysulfone resins, made by the copolymerization of olefins such as 1-butene with sulfur dioxide 24). Both these feed stocks could be derived in abundant quantities and at relatively low costs from petroleum sources. The polysulfone resins are moldable thermoplastic polymers having physical properties that vary widely depending on the olefin from which they are prepared. They are considered to have excellent prospects for development to a large volume, low cost commercial plastic and may permit the entrance of plastic products into other fields in which they are now limited by the high cost and inadequate supply of present thermoplastic materials. 

The kinetic technique was extensively used by Dainton and his associates (3, 4) particularly in their studies of the copolymerization of olefins with sulfur dioxide to 1 1 polysulfones. To check their results, they compared the heats of polymerization calculated from the ceiling... 

Spontaneous copolymerization of cyclopentene (CPT) with sulfur dioxide (SOt) suggests the participation of a charge transfer complex in the initiation and propagation step of the copolymerization. The ESR spectrum together with chain transfer and kinetic studies showed the presence of long lived SOg radical. Terpolymerization with acrylonitrile (AN) was analyzed as a binary copolymerization between CPT-SOt complex and free AN, and the dilution effect proved this mechanism. Moderately high polymers showed enhanced thermal stability, corresponding to the increase of AN content in the terpolymer. 

The best-studied were two film systems the chlorination reaction in a solid solution of Cl2 in BC and the copolymerization reaction of sulfur dioxide with isoprene. Under the above-described conditions of cooling, the liquid films in both systems vitrified. 

Thermogravimetric Analysis. PMMA prepared by initiation with low concentrations of sulfur dioxide at or near room temperature has been found to incorporate from negligible amounts to trace quantities of SOu at chain ends and/or at any other part of the chain presumably by copolymerization (15). Thermogravimetric analysis of a few PMMA samples prepared in the presence of SOu under varied conditions has... 

Iwatsuki and Yamashita (46, 48, 50, 52) have provided evidence for the participation of a charge transfer complex in the formation of alternating copolymers from the free radical copolymerization of p-dioxene or vinyl ethers with maleic anhydride. Terpolymerization of the monomer pairs which form alternating copolymers with a third monomer which had little interaction with either monomer of the pair, indicated that the polymerization was actually a copolymerization of the third monomer with the complex (45, 47, 51, 52). Similarly, copolymerization kinetics have been found to be applicable to the free radical polymerization of ternary mixtures of sulfur dioxide, an electron donor monomer, and an electron acceptor monomer (25, 44, 61, 88), as well as sulfur dioxide and two electron donor monomers (42, 80). 

Spontaneous 1 1 copolymerization has been noted when sulfur dioxide was bubbled through bicycloheptene at —40°C. (88), when isobutylene was bubbled through methyl a-cyanoacrylate (54), when 1,3-dioxole was mixed with maleic anhydride (17), and when vinylidene cyanide was mixed with styrene (20), the latter reactions at room temperature. None of these monomers undergoes homopolymerization under the same experi-... 

Expandability. Polybutene sulfone is insoluble in 1-butene but is soluble in sulfur dioxide. The higher the concentration of 1-butene in 1-butene-sulfur dioxide mixture, the lower is the solubility of the copolymer in this mixture. Even when copolymerization takes place with an excess of sulfur dioxide, the two monomers react in equimolecular... 

At the end of copolymerization C-4 hydrocarbons are added before removal of the unreacted sulfur dioxide. Sulfur dioxide favors the diffusion of C-4 hydrocarbons into the beads and allows a good and homogeneous distribution. Finally, the unreacted sulfur dioxide is removed. Since sulfur dioxide dissolves polybutene sulfone, its diffusion rate is very high in contrast with the hydrocarbons which diffuse slowly and remain occluded in the beads. 

Suspension copolymerization of 1-butene and sulfur dioxide can lead to expandable beads. The cellular material obtained has improved properties with respect to expanded polystyrene. The manufacture of expandable beads by suspension copolymerization is covered by a patent... 

Sulfur dioxide reacts generally with transition metal alkyl, aryl, and a-allyl complexes to give sulfinate complexes. The reaction, first described in 1964 by Wojcicki and Bibler, resembles well-known insertion reactions of CO, C2F4, SnCl2, tetracyanoethy-lene, and other unsaturated species into metal-alkyl bonds, but there are important stereochemical and mechanistic differences Sulfur dioxide insertion into metal-alkene and metal-alkyne bonds have not been reported. However, PdCl2 has been used as a catalyst for copolymerization of ethylene and SO2 to polysulfones and insertion into a Pd-ethylene bond is a conceivable reaction step. 

Materials. Poly(3-butenyltrimethylsilane sulfone) (PBTMSS) was synthesized by free-radical copolymerization of 3-butenyltrimethylsilane with liquid sulfur dioxide (molar ratio 1 9) initiated with azobisisobutyronitrile (AIBN) at 35X in a sealed glass ampoule. The detailed preparation procedure and properties of this copolymer have been reported elsewhere. (7 3)... 

Sulfur dioxide and carbon dioxide, either of which is unable to homopolymerize, are known to easily give copolymers with cyclic compounds. In this way C02 copolymerizes cationically with aziridines 90) ... 

The sulfonylation of alkyl radicals plays an important role in the copolymerization of olefins with sulfur dioxide [53a]. In a recent study, Shevlin [53b] has shown that the cyclooligomerization of diallyl malonate could be controlled by the addition of a chain transfer agent such as PhSH (Eq. 22). 

Ethanal is the most important of these compounds (Table 2.6). The many ways it can be produced and its high reactivity (the CHO radical has extensive chemical affinities), as well as its rapid combination with sulfur dioxide at low temperatures and its organoleptic properties, make ethanal a very important component of wine. The presence of ethanal, produced by the oxidation of ethanol, is closely linked to oxidation-reduction phenomena. It is involved in the alcoholic fermentation mechanism. Furthermore, ethanal plays a role in the color changes occurring in red wines during aging by facilitating the copolymerization of phenols (anthocyanins and catechins) (Section 6.3.10). 

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