Sulfone oligomers reaction

Arylether Sulfone Oligomers with Acetylene Termination from the Ullman Ether Reaction... 

Figure 1. Reaction sequence for AT arylether sulfone oligomers.

In conclusion, the hydroxyl terminated poly(arylene ether sulfone) oligomers of controllable molecular weight were synthesized by the NMP/K CO route. These oligomers were isolated and reacted in a second step with terephthaloyl chloride with or without added biphenol to form segmented copolymers. This second reaction was performed either in solution or interfacial-ly. It was found that the interfacial process allowed a higher percentage... 

The first step in the production of glyceryl ether sulfonates is the production of the intermediate glyceryl ether. There is a multitude of potential reactants that can be used as discussed in Section 8.2.1. Additionally, this reaction is an oligomer reaction, and hence, the intermediate is characterized by multiple chemical species, not just one. 

Another triamine monomer (l,3,5-tris(4-aminophenoxy)benzene, TAPE) has been used as cross-linking agent by Yin et aL [114,115] (Fig. 25). Typically, anhydride-terminated sulfonated oligomers are prepared from BAPBDS and NTDA in m-cresol at 180 °C for 20 h. After adding some triamine monomer, in a second step, the reaction medium is kept at moderate temperature (50 °C), resulting in a polyamic acid intermediate. By a thermal treatment at high temperature or in the presence of an acetic an-hydride/pyridine mixture, complete imidization is performed during film formation. 

The second source of sulfonic acid uses the following reaction scheme alkylation of benzene by a propylene oligomer then sulfonation of the alkylbenzene. 

Although low-molar-mass aliphatic polyesters and unsaturated polyesters can be synthesized without added catalyst (see Sections 2.4.1.1.1 and 2.4.2.1), the presence of a catalyst is generally required for the preparation of high-molar-mass polyesters. Strong acids are very efficient polyesterification catalysts but also catalyze a number of side reactions at elevated temperature (>160°C), leading to polymers of inferior quality. Acid catalysts are, therefore, not much used. An exception is the bulk synthesis of hyperbranched polyesters reported in Section 2.4.5.1, which is carried out at moderate temperature (140°C) under vacuum in the presence of p-toluene sulfonic acid catalyst. The use of strongly acidic oil-soluble catalysts has also been reported for the low-temperature synthesis of polyester oligomers in water-in-oil emulsions.216... 

Bis-o-quinodimethanes have also been used to functionalize [60]-fullerene by Diels Alder reaction. An example is the preparation of main-chain polymers with incorporated [60]-fullerene units [48] illustrated in Scheme 2.20. Cycloaddition of bis-diene 50 generated in situ from bis-sulfone 49 with [60]-fullerene leads to an oligomer mixture 51. Another type of functionalization is based on the... 

The most convenient method of preparing the flexible (low Tg) system is to employ the Ullmann ether reaction of dibromobenzene and aromatic bis-diols followed by catalytic replacement of the bromine atoms by terminal acetylene groups. A host of commercially available bis-diols have been used in the synthesis with both meta and para dibromobenzene. Low Tg arylether oligomers have been prepared containing sulfone, sulfide, carbonyl, isopropyl and perfluoroisopropyl groups in the backbone (9). 

Monomer/Oligomer Synthesis. The first two steps in the four step reaction sequence of Figure 1 are capable of producing both monomer and oligomer. The first step, aromatic nucleophilic substitution, is a polymer forming reaction under the correct stoichiometric conditions. In order to favor the formation of monomer with a small amount of oligomer, the substitution was carried out at a 4 1 ratio of diol to dichlorodiphenyl sulfone. This led to a predominantly monomeric product (IV) with only the requirement that the excess diol be removed from the product to eliminate the potential presence of low molecular weight species in later reactions. 

It should be noted that one of these diols, the hydroquinone, did not provide any oligomer in the first step. This was due to the formation of the quinone structure which made it impossible to use hydroquinone directly in the substitution reaction. An alternate method was used to overcome this problem which involved the use of 4-methoxyphenol to obtain the sulfone product, followed by cleavage of the methyl ether to the diol (VIII) with boron tribromide. This set of reactions is outlined in Figure 5. 

All of the sulfone diols were able to form oligomers in the second step of the reaction sequence, the Ullmann ether synthesis. As with the synthesis of the mono(bromophenoxy)phenol products, two methods were used to form the dibromo materials. Method A used pyridine, potassium carbonate and cuprous iodide, while Method B employed collidine and cuprous oxide with the dibromobenzene and higher molecular weight diol (IV). The major difference between the syntheses of the mono(bromophenoxy)phenols described earlier and these lies in the stoichiometry of the reactions. In order to... 

The monomer/oligomer mixtures were used In the third step of the reaction sequence, the replacement of bromine with 2-methyl-3-butyn-2-ol by use of the bls(trlphenylphosphlne) palladium chloride catalyst system. This reaction used a trlethylamine/pyridine solvent system to replace the bromines on the ether sulfone with ethynyl groups protected by acetone adducts. The acetone protecting groups were then removed In a toluene/methanol/potasslum hydroxide solvent system. 

Brominated Monomer/Oligomer Mixtures from IV (V). The brominated sulfone monomer/oligomer mixtures were preparedby two different methods. Method A A mixture of pyridine (70mL), IV (11.5 mmol), dibromobenzene (26.96g, 115 mmol), anhydrous potassium carbonate (7.94g, 57.5 mmol) and cuprous iodide (0.13g, 0.7 mmol) was heated at reflux under nitrogen for 24h. After cooling to room temperature, the reaction mixture was acidified with IN HC1 and the aqueous solution extracted with ether. The organic phase was reduced in volume to a brown gum which was washed several times with hexane and then dried to give a 75-95% yield of the dibromo product. 

An example for the synthesis of poly(2,6-dimethyl-l,4-phenylene oxide) - aromatic poly(ether-sulfone) - poly(2,6-dimethyl-1,4-pheny-lene oxide) ABA triblock copolymer is presented in Scheme 6. Quantitative etherification of the two polymer chain ends has been accomplished under mild reaction conditions detailed elsewhere(11). Figure 4 presents the 200 MHz Ir-NMR spectra of the co-(2,6-dimethyl-phenol) poly(2,6-dimethyl-l,4-phenylene oxide), of the 01, w-di(chloroally) aromatic polyether sulfone and of the obtained ABA triblock copolymers as convincing evidence for the quantitative reaction of the parent pol3rmers chain ends. Additional evidence for the very clean synthetic procedure comes from the gel permeation chromatograms of the two starting oligomers and of the obtained ABA triblock copolymer presented in Figure 5. 

Porous affinity membranes based on hydrolyzed poly(GMA-co-EDMA) grafted with glicidyl methacrylates oligomers were also reported [2,60]. Tennikova et al. [2] prepared functionalized macroporous poly(GMA-co-EDMA) membranes by reaction with propane sulfone, diethylamine, or water, leading to the formation of corresponding sulfonic acid, diethylamino or diol-derivatized stationary chromatographic phases. Unfortunately, the poly(GMA-co-EDMA) membranes are mechanically weak and due to their hydrophobic character may cause nonspecific adsorption of proteins. 

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