Sulfur dioxide olefination

Copolymers have also been prepared using mixtures of olefins with sulfur dioxide. Olefin pairs studied were butene with propylene [22-22b], butene with pentene [13], butene with isobutene [13b], butene with acrylonitrile [13,23], butene with vinyl acetate [24], butene with methacrylate esters [25], butene with acrylic esters [25], and butene with butadiene [24]. 

A polysulfone is characterized by the presence of the sulfone group as part of its repeating unit. Polysulfones may be aUphatic or aromatic. AUphatic polysulfones (R and are alkyl groups) were synthesized by radical-induced copolymerization of olefins and sulfur dioxide and characterized many years ago. However, they never demonstrated significant practical utiUty due to their relatively unattractive physical properties, not withstanding the low cost of their raw materials (1,2). The polysulfones discussed in this article are those based on an aromatic backbone stmcture. The term polysulfones is used almost exclusively to denote aromatic polysulfones. 

A number of processes have been devised for purifying thionyl chloride. A recommended laboratory method involves distillation from quinoline and boiled linseed oil. Commercial processes involve adding various high boiling olefins such as styrene (qv) to react with the sulfur chlorides to form adducts that remain in the distillation residue when the thionyl chloride is redistilled (179). Alternatively, sulfur can be fed into the top of the distillation column to react with the sulfur dichloride (180). Commercial thionyl chloride has a purity of 98—99.6% minimum, having sulfur dioxide, sulfur chlorides, and sulfuryl chloride as possible impurities. These can be determined by gas chromatography (181). 

The reaction of sulfur dioxide with olefins under free-radical-cataly2ed conditions produces copolymers which, ia most cases, are of an alternating 1 1 type (249,250) ... 

A iD-Corticoids have been important intermediates since it was shown ° that substitution at C-9 enhances anti-inflammatory activity. These olefins are usually obtained from 11a- or 11)5-alcohols, and consequently several refined methods have been devised for effecting this dehydration. It is desirable that such methods be compatible with the presence of A" -3-ketone and 17-hydroxy functions. The first direct procedure for which high yields were claimed was described in a patent issued to Upjohn. According to this method, the alcohol (11a or )5) is treated first with A-bromoacetamide in pyridine, then with sulfur dioxide. Recently it has been claimed " that the A-haloamide/sulfur dioxide method gives results superior to other methods, although the methanesulfonyl chloride/sulfur dioxide procedure (see below) apparently was not compared (see also ref. 94). 

From the results of other authors should be mentioned the observation of a similar effect, e.g. in the oxidation of olefins on nickel oxide (118), where the retardation of the reaction of 1-butene by cis-2-butene was greater than the effect of 1-butene on the reaction of m-2-butene the ratio of the adsorption coefficients Kcia h/Kwas 1.45. In a study on hydrogenation over C03O4 it was reported (109) that the reactivities of ethylene and propylene were nearly the same (1.17 in favor of propylene), when measured separately, whereas the ratio of adsorption coefficients was 8.4 in favor of ethylene. This led in the competitive arrangement to preferential hydrogenation of ethylene. A similar phenomenon occurs in the catalytic reduction of nitric oxide and sulfur dioxide by carbon monoxide (120a). 

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... 

In a typical procedure61144 the sulfonyl chloride in ether is added to an etheral solution of the diazoalkane and triethylamine. Filtration and evaporation gives the relatively pure thiirane dioxide. Further purification can be easily achieved by recrystallizations preferentially below room temperature in order to avoid fragmentation of the product into sulfur dioxide and the olefin. In general, when the temperature of the above reaction is lowered, the yields are improved without a drastic decrease in reactivity144. Many thiirane dioxides have been successfully synthesized through this method and a detailed list of them can be found elsewhere2. 

Another procedure145 consists of bubbling of sulfur dioxide through a chilled solution of diazomethane in ether146. Evaporation of the solvent leaves the crude thiirane dioxide, which can be further purified by either distillation under reduced pressure or recrystallization. The formation of the thiirane dioxides is usually accompanied by formation of the corresponding olefins, along with small amount of ketazines. 

As formal a, /i-unsaturated sulfones and sulfoxides, respectively, both thiirene dioxides (19) and thiirene oxides (18) should be capable, in principle, of undergoing cycloaddition reactions with either electron-rich olefins or serving as electrophilic dipolarophiles in 2 + 3 cycloadditions. The ultimate products in such cycloadditions are expected to be a consequence of rearrangements of the initially formed cycloadducts, and/or loss of sulfur dioxide (or sulfur monoxide) following the cycloaddition step, depending on the particular reaction conditions. The relative ease of the cycloaddition should provide some indication concerning the extent of the aromaticity in these systems2. 

One of the most important reactions of sulfones in general is the R amberg Backlund rearrangement, which involves the conversion of a-halosulfones to olefins with accompanying loss of hydrogen halide and sulfur dioxide under basic conditions (equation 48)151. 

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). 

Sulfur dioxide (see above) as well as S02, SO , and SOj have been used as building blocks in three-component sulfone syntheses. It has long been known that aromatic sulfinic acids are easily available from diazonium salts and sulfur dioxide under copper catalysis . Mechanistically, aryl radicals as reactive intermediates add to sulfur dioxide generating arenesulfonyl radicals, which either take up an electron (or hydrogen) yielding a sulfinic acid or add to an olefinic double bond yielding final y -halogenated alkyl aryl sulfones (equation 78). 

The electrophilic character of sulfur dioxide does not only enable addition to reactive nucleophiles, but also to electrons forming sulfur dioxide radical anions which possess the requirements of a captodative" stabilization (equation 83). This electron transfer occurs electrochemically or chemically under Leuckart-Wallach conditions (formic acid/tertiary amine - , by reduction of sulfur dioxide with l-benzyl-1,4-dihydronicotinamide or with Rongalite The radical anion behaves as an efficient nucleophile and affords the generation of sulfones with alkyl halides " and Michael-acceptor olefins (equations 84 and 85). 

Finally, the most significant mechanistic feature of the Ramberg-Backlund rearrangement is the stereoselective formation of ds-olefin products, as a result of the preferential cis-positioning of the pair of R groups in the episulfone-forming transition state, variously attributed to London forces , to diastereoselectivity in carbanion formation and to steric attraction . However, with the use of stronger bases such as potassium t-butoxide °, the trans-olefin predominates (equation 52), apparently due to prior epimerization of the kinetically favoured cts-episulfone, and subsequent loss of the sulfur dioxide. Similarly, when the episulfone intermediates possess unusually acidic... 

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... 

Drent, E. U. S. Catalytic process for preparing polymers of sulfur dioxide and olefins. Patent 4,808,697, 19890228. 

The sulfoxidation of aliphatic hydrocarbons is the easiest method for the synthesis of alkylsulfonic acids. Their sodium salts are widely used as surfactive reactants in technology and housekeeping. Platz and Schimmelschmidt [1] were the first to invent this synthetic method. Normal paraffins (Ci4-Cig) are used for the industrial production of alkylsulfonic acids [2-4]. Olefins and alkylaromatic hydrocarbons do not produce sulfonic acids under the action of sulfur dioxide and dioxygen and retard the sulfoxidation of alkanes [5-9],... 

Another class of "chain scission" positive resists is the poly(olefin sulfones). These polymers are alternating copolymers of an olefin and sulfur dioxide. The relatively weak C-S bond is readily cleaved upon irradiation and several sensitive resists have been developed based on this chemistry (49,50). One of these materials, poly(butene-l sulfone) (PBS) has been made commercially available for mask making. PBS exhibits an e-beam sensitivity of 1.6 pC cm-2 at 20 kV and 0.25 pm resolution. 

Some work [5] has been performed on the photochemical reaction between sulfur dioxide and hydrocarbons, both paraffins and olefins. In all cases, mists were found, and these mists settled out in the reaction vessels as oils with the characteristics of sulfuric acids. Because of the small amounts of materials formed, great problems arise in elucidating particular steps. When NO and 02 are added to this system, the situation is most complex. Bulfalini [3] sums up the status in this way The aerosol formed from mixtures of the lower hydrocarbons with NO and S02 is predominantly sulfuric acid, whereas the higher olefin hydrocarbons appear to produce carbonaceous aerosols also, possibly organic acids, sulfonic or sulfuric acids, nitrate-esters, etc. ... 

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