Bisphenol Hydrolysis products

In the industrial production of this PC, interfacial polycondensation is used. The bisphenol A is first dissolved in the aqueous phase as sodium salt, and the phosgene in the organic phase, which is not miscible with water, e.g. dichloromethane. The reaction occurs at the interface of the two phases to produce oligomers, which enter the organic phase. The hydrolysis product NaCl enters the aqueous phase. The addition of catalysts (tertiary amines) accelerates the polycondensation process. The chlorine leaves the process as sodium chloride, see Fig. 96. 

Phthalic and isophthalic resins are hydrolyzed by 60 °C hot water here, the rate of hydrolysis noticeably increases with temperature. The water washes the hydrolysis products out of the resin. Because this process superposes absorption, weight change in glass fiber-reinforced polyester resins caused by exposure to warm water is lower than caused by water at 20 °C. At 100 °C, however, the effect of water on glass fiber-reinforced phthalic and isophthalic resins results in severe weight loss and the formation of deposits in water, a clear indication of degradation. Bisphenol-based resins are more resistant to water. Table 5.116 [32]. 

Some of the reaction products of polymerisation and cure can be toxic, for example, aromatic amines from hydrolysis of isocyanates and bisphenol A from... 

Figure 10-5 Molecular structures of BADGE and hydrolysis/ethanolysis products (1) Bisphenol A diglycidyl ether (BADGE)-, (2) Bisphenol A (2,3-dihydroxypropyl ether) diglycidyl ether (diol-epoxide) (3) Bisphenol A di-(2,3-dihydroxypropyl ether) (diol-diot) (4) Bisphenol A (3-ethoxy-2-hydroxypropyl ether) diglycidyl ether (ether-epoxide)-, (5) Bisphenol A (3-ethoxy-2-hydroxypropyl ether) (2,3-dihydroxypropyl ether) (ether-diol).

The chromatographic SMB reactor has been examined for various reaction systems, with the main focus on reactions of the type A + B C + D. Examples are esterifications of acetic acid with methanol (Lode et al., 2003b), ethanol (Mazotti et al., 1996a) and (5-phenethyl alcohol (Kawase et al., 1996) as well as the production of bisphenol A (Kawase et al., 1999). The same reaction type can also be found for various hydrocarbons, such as the transfer reaction of sucrose with lactose to lactosuc-rose (Kawase et al., 2001) and the hydrolysis of lactose (Shieh and Barker, 1996). Barker et al. (1992) focused on reactions of the type A B + C, such as enzyme-catalyzed sucrose inversion and the production of dextran. Also, reactions of the type A tB have been investigated, e.g. isomerization of glucose to fructose by Fricke (2005) as well as Tuomi and Engell (2004). Michel et al. (2003) have examined the application of electrochemical SMB reactors for consecutive reactions and used as an example the production of arabinose. 

Interfacial polycondensation is an interesting procedure that is often used in demonstrations in polymer chemistry courses. Polyamides are prepared rapidly, in fiont of the class, from diacid chlorides and diamines. The products are removed quickly as they form, by pulling them out as a string from the interface." Polyesters can also be prepared from diacid chlorides and bisphenols. On the other hand, preparation of polyesters from glycols and diacid chlorides is usually unsuccessful due to low reactivity of the dialcohols. The diacid chlorides tend to undergo hydrolysis instead. Commercially, this procedure is so far confined mainly to preparations of polycarbonates (discussed further in this chapter). 

Polysulfone is thermo-mechanical and chemically durable thermoplast. But in solution, which is catalyzed by alkali, it becomes sensitive to nucleoph-ylic replacements. In polar aprotone dissolvents at temperatures above 150 °C in the presence of spirit solution of K COj it decomposes into the bisphenol A and diarylsulfonic simple esters. The analogous hydrolysis in watery solution of K2CO3 goes until phenol products of decomposition. This reaction is of preparative interest for the synthesis of segmented block-copolyester simple polyester - polysulfone. The transetherification of polysulfone, being... 

Methacrylamide monomers were also considered (Scheme 2.2). 2-Metha-crylamidoethylphosphonic acid was prepared from the expensive (2-ami-noethyl)phosphonic acid in one step. Other monomers (Scheme 2.2, monomers 1 and 2) were synthesized from bisphenol A diglycidyl ether. The ring-opening of epoxides was achieved with aqueous ammonia at high temperature and pressure and the subsequent reaction with diethyl (2-bromoethyl)phosphonate led either to mono- or disubstituted product. Targeted monomers were finally obtained after (i) reaction with methacryloyl chloride and (ii) hydrolysis of the phosphonated ester groups. 

Diaminodiphenylmethane is an aromatic diamine used as a curing agent in epoxy resins of the bisphenol A type, as in the production of plastics, isocyanates, adhesives, elastomers, polyurethane (elastic and rigid foams, paints, lacquers, adhesives, binding agents, synthetics rubbers, and elastomeric fibers) and butyl rubber. Diaminodiphenylmethane is also a by-product of azo dyes. It is also possibly formed by hydrolysis of diphenylmethane-4,4 -diisocyanate. 

Processes were developed in recent years in order to recover raw materials from poly(ethylene terephtalate) (PET) and polycarbonate (PC) by hydrolysis. The main focus was the recovery of terephthalic acid and ethylene glycol besides other products such as benzene, salts of terephthalic acid and oxalic acid. Processes developed for PET are also valid for polyesters such as poly(butylene terephthalate) (PBT) and poly(ethylene 2,6-napthalene dicarboxylate) (PEN). The recovery of bisphenol-A (BPA) from PC requires more sophisticated methods due to the low stability of BPA at high temperatures. Often phenol and isopropenyl phenol are obtained as degradation products of BPA. 

Based on analysis of products distribution [25], it was concluded that there were two kinds of decomposition action hydrolysis mainly at lower temperature and pyrolysis mainly at higher temperature. At low-temperature stage, the brominated epoxy resin was mainly decomposed into bisphenol A, brome-phenol, isopropyl phenol monomer, etc., while at high-temperature stage, the brominated epoxy resin was mainly decomposed into phenol, o-cresol, p-cresol, and other small molecule compormds without bromine. 

The hydrolysis-methylation products are then pyrolysed and the pyrolysis products examined by gas chromatography to provide knowledge on polymer structure. This technique has been applied in hydrolysis - methylation - Py-GC to polycarbonates and phenolics. Polycarbonate main chains degraded quantitatively at the carbonate linkages to yield dimethyl derivatives of breakdown products such as bisphenol A. Such studies provided information on polymer structure including end-group analysis. 

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