Polymers, sulfur containing sulfonation

Effective catalysts for preparing the polyformals were p-toluenesulfonic acid, camphorsulfonic acid, methanedisulfonic acid, and perchloric acid. Various other acidic compounds were evaluated as catalysts with tetramethylcyclobutanediol. In these experiments, 0.5 to 1.0 gram of acidic compound per mole of tetramethylcyclobutanediol was normally added. If insufficient water was obtained, more catalyst was added. If the prepolymer was obtained but an appreciable amount of brown color was present, less catalyst was then used. Compounds which did not catalyze the reaction (no water obtained) were phosphoric acid, zinc chloride, trifluoroacetic acid, and heptafluorobutyric acid. Incomplete reactions (insufficient water) took place with concentrated hydrochloric acid, concentrated nitric acid, zinc fluoroborate, or Amberlite IRC-50 ion exchange resin as catalyst. A prepolymer was obtained when boron trifluoride etherate was used, but buildup did not take place in the solid phase (catalyst probably too volatile). Brown or speckled-brown polymers (after solid-phase buildup) were obtained with catalysts containing sulfonic acid groups (benzenesulfonic, dodecylbenzenesulfonic, sulfo-acetic, methanetrisulfonic, sulfuric, p-toluenesulfonic, camphorsulfonic, and methanedisulfonic acids). To obtain white polymers from tetramethylcyclobutanediol it was necessary to treat the solvent and prepolymer reaction mixture as previously described. (White polyformals were obtained from the other diols without this treatment.)... 

Sulfur is part of a considerable number of polymers although not necessarily included in the polymer backbone. For example, the presence of -S-S- bridges between polymeric chains is well known for vulcanized rubber. Since the bridges are not part of the polymeric main chains, vulcanized rubber is classified together with the polymers containing double bonds in the backbone and is discussed in Section 7.2. Also sulfonic groups are present in polymers such as sulfonated styrenes (see Section 6.6) with important ion exchange properties. 

Poly(arylene ether)s are one of the most studied aromatic polymers for the sulfonation reactions. Poly(arylene ether)s include poly(phenylene ether), poly(arylene ether ketone), poly(arylene ether ether ketone), and poly(arylene ether sul-fone). These polymers contain electron-rich phenylene rings linked by ether bonds, which are susceptible for the sulfonation reactions with typical sulfonating reagents such as sulfuric acid, chlorosulfonic acid, or sulfur trioxide. The first attempt was the sulfonation of poly(2,6-dimethyl-phenylene ether) (PPO) by General Electric in 1960s [4]. Since then, a number of... 

Sulfur-containing polymers, including poly-sulfone (PSU), polyphenylenesulfone (PPSU), and polyphenylene sulfide (PPS)... 

There are a few routes to synthesize sulfone functionalities for solid phase chemistry. One possibility is the reaction of lithiated polystyrene beads with sulfur dioxide to deliver polymer-bound lithium phenyl sulfinate as a linker system to which allylic compounds can be easily attached [286]. Other syntheses start from the corresponding thioether linkage followed by oxidation to the sulfone. Mostly, sulfur-containing ether-linkers that are oxidized just before cleavage from the resin are presented separately from those which are directly bound to the resin in their oxidized form. This differentiation is not done in this review because it does not make any difference concerning the cleavage possibilities that are shown in Scheme 66. 

The aromatic sulfone polymers are a group of high performance plastics, many of which have relatively closely related stmctures and similar properties (see Polymers containing sulfur, polysulfones). Chemically, all are polyethersulfones, ie, they have both aryl ether (ArOAr) and aryl sulfone (ArS02Ar) linkages in the polymer backbone. The simplest polyethersulfone (5) consists of aromatic rings linked alternately by ether and sulfone groups. 

An example of a sulfite ester made from thionyl chloride is the commercial iasecticide endosulfan [115-29-7]. A stepwise reaction of thionyl chloride with two different alcohols yields the commercial miticide, propaigite [2312-35-8] (189). Thionyl chloride also has appHcations as a co-reactant ia sulfonations and chlorosulfonations. A patent describes the use of thionyl chloride ia the preparation of a key iatermediate, bis(4-chlorophenyl) sulfone [80-07-9] which is used to make a commercial polysulfone engineering thermoplastic (see Polymers CONTAINING SULFUR, POLYSULFONe) (190). The sulfone group is derived from chlorosulfonic acid the thionyl chloride may be considered a co-reactant which removes water (see Sulfolanes and sulfones). 

Sulfur(II)-containing compounds possess the reducing activity and react with hydroperoxides and peroxyl radicals [1-5]. They are employed as components of antioxidant additives to lubricants and polymers [30-35]. Denison and Condit [36] were the first to show that dialkyl sulfides are oxidized by hydroperoxides to sulfoxides and then to sulfones... 

Insoluble polystyrene crosslinked with divinylbenzene can easily be converted by sulfonation to a usable ion exchanger. For this purpose a mixture of 0.2 g of silver sulfate and 150 ml of concentrated sulfuric acid are heated to 80-90 °C in a 500 ml threenecked flask fitted with stirrer, reflux condenser, and thermometer. 20 g of a bead polymer of styrene and divinylbenzene (see Example 3-41) are then introduced with stirring the temperature climbs spontaneously to 100-105 °C.The mixture is maintained at 100 C for 3 h,then cooled to room temperature and allowed to stand for some hours. Next the contents of the flask are poured into a 11 conical flask that contains about 500 ml of 50% sulfuric acid. After cooling, the mixture is diluted with distilled water, and the gold-brown colored beads are filtered off on a sintered glass filter and washed copiously with water. 

Even so, a number of chemical agents, including liquids, chemically attack polymers. Reactions that would ordinarily occur with small molecules also occur in polymers, given the same functional groups and reactive sites. Thus benzene, toluene, etc., are readily sulfonated when exposed to sulfuric acid. Likewise polystyrene (PS) is sulfonated when exposed to liquids and gases containing sulfuric acid ... 

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