ChemInform Abstract: Chemistry in Superacids. Part 23. Preparation of Condensed Aromatics by Superacidic Dehydrative Cyclization of Aryl Pinacols and Epoxides.

Klumpp, Douglas A.; Baek, Donald N.; Prakash, G. K. Surya; Oláh, George A.

doi:10.1002/chin.199803108

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“…85 A number of diarylated syntheses catalyzed by a superacid has been reported in the literature. The protonation of the 1,2-dicarbonyl group, 62,96,97 aldehydes, 98,99 nitriles 100 and other systems [101][102][103][104][105] resulted in the formation of highly reactive dication intermediates, which are sufficiently condensed with aromatic compounds. 106 By applying this concept, Zolotukhin et al 107 recently reported that a linear poly(phenylene ether) with a high MW was prepared by polycondensation of 2,2,2-trifluoroacetophenone with 4,4¢-diphenoxybenzophenone in TFSA at room temperature.…”

Section: Linear Polymers Derived From Ab 2 Monomersmentioning

confidence: 99%

Synthesis of hyperbranched polymers with controlled degree of branching

Higashihara

Segawa

Sinananwanich

et al. 2011

Polym J

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Hyperbranched polymers (HBPs) have attracted considerable attention during the past decade because of their intrinsic globular structures and unique properties, such as low viscosity, high solubility and a high degree of functionality, compared with linear analogs. As HBPs are generally prepared by one-pot polycondensation of an AB x monomer, where A and B represent two different functional groups, they are regarded as less-expensive alternatives to dendrimers. However, HBPs have randomly branched structures and their degree of branching (DB) is determined by statistics and only reaches B50%. Recently, several research groups have successfully synthesized a 100% DB without any defect mainly by condensation or addition reactions. These methods are based on a new concept in which the ratio of the rate constants, the first reaction rate constant (k 1 )/the second reaction rate constant (k 2 ) of an AB 2 monomer, can be controlled. Recent development in the synthesis of a linear polymer, that is, a 0% DB HBP, from an AB 2 monomer could make it possible to further precisely control the DB from 0 to 100% by using the same AB 2 monomer. In this review article, the backgrounds and methodologies for controlling the DB are described, especially focusing on recent advances in the synthesis of HBPs with a DB of 100, 0% and any percentage between 0 and 100%.

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