Chlorinated biphenols

In January and March of 1988, Radian Corporation made a comprehensive series of performance measurements on the air pollution control system at Modesto (47). As shown in Table 12, the measurements included chlorinated dibenzo-p-dioxins (CDD), chlorinated dibenzofurans (CDF), polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenols (PCB), total hydrocarbons (THC), ammonia, NOx, sulfur trioxide, sulfur dioxide, hydrochloric acid, carbon monoxide, and particulate matter. 

The optimized geometry of the biphenol MOM ether-SnCU was obtained from a partial PM3 calculation of the MOM units on the basis of a B3LYP/LANL2DZ-opti-mized geometry for a biphenol-SnCU complex (Fig. 5). It is noteworthy that the C5-04 bond is almost perpendicular to the C1-C3 axis, presumably because of the steric repulsive interactions with apical and equatorial chlorines. Also of interest is the observation that the C5-06 bond is shorter than the 04-C5 bond. This indicates that the C5-06 bond has a partial double-bond character because of the stereoelectronic effect and its most stable conformer would be the reactive oxonium intermediate. 

Phenol-ketone novolacs 1487, 1488 Phenol-nitrile complexes 377 Phenol radical cations 1101 fragmentation of 289-291 Phenols—see also Biphenols, Bis-phenols, Hydroxybenzenes, Polyphenols acidities of, gas-phase 310-312 acylation of 629-632, 933, 934 Lewis acid catalyzed 631 montmoriUonite-catalyzed 632 pyridine-catalyzed 631 adsorption of 944 alkylation of 606-629, 941 Brdnsted acid catalyzed 612 Lewis acid catalyzed 607-611 solid acid catalyzed 612-621 stereoselective 621-626 under supercritical conditions 621 as antioxidants 139-143, 840-901 ort/io-substituted 845 thermochemistry of 139, 140, 179 autoxidation of 1118, 1119 bromination of 649-651 jr-cation interaction of 322 chlorination of 649 comparison with isoelectronic methyl, amino and fluoro aromatic derivatives 226... 

High performance thin-film composite membranes for reverse osmosis applications were fabricated by coating solutions of a highly chlorine-tolerant disulfonated PAES [92,93]. As base monomers, 4,4 -dichlorodiphenyl sulfone and 4,4 -biphenol are used. 4,4 -dichlorodiphenyl sulfone is then directly sulfonated to get a disulfonated monomer, 3,3 -disutfonate-4,4 -dichlorodiphenyl sulfone. These monomers can be directly copolymerized on a commercially available porous polysulfone support. 

Biphenol derivatives are quite resistant to hydrolysis and oxidation and have excellent electrical characteristics. The more highly chlorinated types are flame resistant and impart this quality to resins with which they are used. They are of special interest in chlorinated rubber, paints, and PVC electrical compositions. 

Now the most important Route la will be illustrated by means of the synthesis of BIPHEPHOS (Scheme 2.89) [7]. The required biphenyl phosphorchloridite can be prepared by the reaction of PCI3 with 2,2 -dihydroxybiphenol in the presence of NEtj, as suggested by the Amsterdam group [78]. Alternatively, the reaction can be conducted in a suspension of toluene in the absence of a base, under the condition that HCl is removed under vacuum [79]. The chlorophosphite is used in the second step for the condensation reaction with the substituted biphenol in the presence of pyridine. Final crystallization from acetonitrile produces the desired product. Care should be taken with traces of chlorine or acetonitrile, which affects the longterm stability of the diphosphite [80]. These contaminations can be removed by recrystallization, for example, from o-xylene, n-heptane, or ethyl acetate, or by washing with acetone. 

Monomer (29) has two chlorine atoms that differ considerably in their reactivity toward zero-valent nickel. The chlorine in the para position to the sulfone group should react first it is, therefore, expected that the final polymer will have structure (30). Polymer (30) can also be synthesized via the nucleophilic route by polycondensing 4,4 -bis(p-chlorophenylsulfonyl) biphenyl (31) with 4,4 -biphenol (32) [equation (VIII)] ... 

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