Bisphenol-A groups

The bisphenol-A group 2,18) is a very common structural unit in many polycondensation polymers, such as epoxy resins (section 4.3), polycarbonates (section 4.5), polyesters (section 4.6.4), polysulphones and polyethersulphones (section 4.12). Under UV irradiation the bisphenol-A group can be cleaved to 

The photo-Fries rearrangement, may occur simultaneously, with the formation of ortho-hydroxy phenyl groups (2.23)  

It is also possible that some free radical R or P can abstract hydrogen from the methyl groups giving a new polymeric radical (2.24)  

In the presence of oxygen all polymeric radicals (2.19)-(2.22) and (2.24) (denoted here as P ) can be oxidized to polymer peroxy (POj) radicals. 

All of these polymeric radicals (P, PO , PO2) can terminate each other giving crosslinked structures (cf. section 2.13). 

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The presence of the biphenol group in compounds VI, VII, AND VIII as opposed to the bisphenol A group is based on a number of factors ... 

Formation of mono- and di-quinone groups can be responsible for the yellowing of all polymers containing bisphenol-A groups. 

Acrylated epoxidized linseed oil Acrylated epoxidized soybean oil a-Hydoxy ketone Bisacylphosphine oxide Oligomer containing bisphenol A groups... 

Percec et al7 used Method 1 to determine of polyether sulfones (PESs) such as 34. Their polymers did not yield H ID-NMR spectra with resolved resonances from the chain end. They incorporated a 3,5-dinitrobenzoyl (DNB) tag at the polymer chain ends by producing the ester derivative, 35, from reaction of the polymer with 3,5-dinitrobenzoyl chloride. Incorporation of nitro groups into aromatic rings shifts the ortho and para protons far downfield compared to other typical aromatic proton resonances such as those in the PESs. They calculated DP from ratio of polyether sulfone methyl (Apes) to 3,5-dinitrobenzoyl (Adnb) peak areas in the H NMR spectrum, corrected for the number of protons in each group, as shown in eqn [46]. Note that the sulfone and bisphenol A groups together were treated as the repeat unit in this analysis. M can then be calculated using eqn [36], with a correction factor to account for the MW of the chain-end structures. This method assumes that all chain ends react with the DNB tag an assumption that is not always valid. 

Fig. 23. Representative protecting groups for phenolic and carboxylic acid-based systems, (a) The polymer-based protecting groups are fisted in order of increasing activation energy for acid-catalyzed deprotection, (b) Acid-labile monomeric dissolution inhibitors, a bifunctional system based on protected bisphenol A. (c) Another system that combines the function of dissolution inhibitor and PAG in a single unit.

The para and ortho positions of phenols condense at the carbonyl group of acetone to make bisphenols, eg, bisphenol A, 4,4 -(l-methylethyhdene)bisphenol [80-05-07]). If the H atom is activated, CICH— compounds add to the carbonyl group in the presence of strong base chloroform gives chloretone (l,l,l-trichloro-2-methyl-2-propanol [57-15-8]). 

The Brominated Flame Retardants Industry Panel (BFRIP) was formed ia 1985 within the Flame Retardant Chemicals Association (FRCA) to address such concerns about the use of decabromodiphenyl oxide. Siace 1990 the BFRIP has operated as a Chemical Self-Funded Technical Advocacy and Research (CHEMSTAR) panel within the Chemical Manufacturers Association (CMA) (64). As of 1993, members of BFRIP are Ak2o, Amerihaas (Dead Sea Bromine Group), Ethyl Corp., and Great Lakes Chemical. Siace its formation, BFRIP has presented updates to iadustry on a regular basis (65,66), and has pubhshed a summary of the available toxicity information on four of the largest volume brominated flame retardants (67,68) tetrabromo bisphenol A, pentabromodiphenyl oxide, octabromodiphenyl oxide, and decabromodiphenyl oxide. This information supplements that summarized ia Table 11. 

A polyester backbone with two HFIP groups (12F aromatic polyester of 12F-APE) was derived by the polycondensation of the diacid chloride of 6FDCA with bisphenol AF or bisphenol A under phase-transfer conditions (120). These polymers show complete solubkity in THF, chloroform, ben2ene, DMAC, DMF, and NMP, and form clear, colorless, tough films the inherent viscosity in chloroform at 25°C is 0.8 dL/g. A thermal stabkity of 501°C (10% weight loss in N2) was observed. 

Fig. 2. Molecular structures of selected photoconductive polymers with pendent groups (1) poly(A/-vinylcarba2ole) [25067-59-8] (PVK), (2) A/-polysiloxane carbazole, (3) bisphenol A polycarbonate [24936-68-3] (4) polystyrene [9003-53-6] (5) polyvin5i(l,2-/n7 j -bis(9H-carba2ol-9-yl)cyclobutane) [80218-52-6]...

Solvent for Displacement Reactions. As the most polar of the common aprotic solvents, DMSO is a favored solvent for displacement reactions because of its high dielectric constant and because anions are less solvated in it (87). Rates for these reactions are sometimes a thousand times faster in DMSO than in alcohols. Suitable nucleophiles include acetyUde ion, alkoxide ion, hydroxide ion, azide ion, carbanions, carboxylate ions, cyanide ion, hahde ions, mercaptide ions, phenoxide ions, nitrite ions, and thiocyanate ions (31). Rates of displacement by amides or amines are also greater in DMSO than in alcohol or aqueous solutions. Dimethyl sulfoxide is used as the reaction solvent in the manufacture of high performance, polyaryl ether polymers by reaction of bis(4,4 -chlorophenyl) sulfone with the disodium salts of dihydroxyphenols, eg, bisphenol A or 4,4 -sulfonylbisphenol (88). These and related reactions are made more economical by efficient recycling of DMSO (89). Nucleophilic displacement of activated aromatic nitro groups with aryloxy anion in DMSO is a versatile and useful reaction for the synthesis of aromatic ethers and polyethers (90). 

Thioglycohc acid is recommended as a cocatalyst with strong mineral acid in the manufacture of bisphenol A by the condensation of phenol and acetone. The effect of the mercapto group (mercaptocarboxyhc acid) is attributed to the formation of a more stable carbanion intermediate of the ketone that can alkylate the phenol ring faster. The total amount of the by-products is considerably reduced (52). 

Epoxy Resins. Epoxy resins (qv) or polyether resins are thermosets used as the binder for terrazzo dooring. The epoxy resin often is made from epichlorohydrin and bisphenol A. An excess of epichlorohydrin is used to assure that the intermediate product contains terminal epoxide groups. 

Epoxy Resins. Epoxy resins (qv) are used to cross-link other resins with amine, hydroxyl, and carboxyHc acid (or anhydride) groups. The epoxy group, properly called an oxkane, is a cycHc three-membered ether group. By far the most widely used epoxy resins in coatings are bisphenol A (BPA) (4,4 -(l-methylethyHdene)bisphenol) [80-05-7] epoxy resins. 

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