Ortho-dichloro-benzene

The asymmetric cross-coupling of the meso-tricarbonyl (ortho-dichloro-benzene)chromium complex with a wide range of vinylic metals in the... 

The susceptibility and correlation length of several dPB(l,4)/PS blends (sample 2 in Table 2) mixed with the non-selective solvent ortho-dichloro-benzene (oDCB) between zero and 16% volume fraction are depicted in Fig. 17 versus inverse temperature. At the maximum solvent content the polymer miscibility has been appreciably improved as evident by the strong decrease of the critical temperature from about 70 to 30 °C [32]. The susceptibility and correlation length show the typical deviation from linear mean field behavior, and the results of the fit with the crossover functions of Eqs. 19 and 16 are shown by the solid lines the agreement between experiment and theory is always good. In nearly all samples the critical condition can well be approached. 

Of the two isomeric dichlorobenzenes, the more valuable crystalline para compound (mp, 53 C) is formed in the largest quantities, the ratio of para to ortho usually being greater than 2 1. In most technical operations, the chlorination is continued until a peak in monochlorobenzene is obtained. The composition of the charge will vary somewhat, depending on the temperature employed, the catalyst used, and the rate and degree of chlorination, but it will be approximately as follows benzene, 9 per cent monochlorobenzene, 70 pfer cent p-dichlorobenzene, 15 per cent and o-dichloro-benzene, including polychloro compounds, 6 per cent. 

The mother liquor which is predominately ortho-dichlorobenzene is fractionated under vacuum, giving a first fraction high in para-dichloro benzene which is returned to the crystallizer system, a main fraction of high-purity ortho-dichlorobenzene, and a polychlorobenzene fraction which is used in trichlorobenzene production. 

Chlorination of benzene is an electrophilic substitution reaction in which CL serves as the electrophile. The reaction occurs in the presence of a Lewis acid catalyst such as FeCls. The products are a mixture of mono- and dichlorobenzenes. The ortho- and the para-dichlorobenzenes are more common than meta-dichlorobenzene. The ratio of the mono-chloro to dichloro products essentially depends on the benzene/chlorine ratio and the residence time. The ratio of the dichloro-isomers (0- to p- to m-dichlorobenzenes) mainly depends on the reaction temperature and residence time ... 

Among benzene derivatives, halogen-substituted compounds have been extensively studied and in the structure-reactivity studies " carried out on the reaction of OH and SO with the ortho and meta isomers of dichloro and dibromobenzenes and mono-bromotoluenes, the formation of substituted hydroxycyclohexadienyl radical was observed to be the major reaction channel. The bimolecular rate constants obtained for the reaction of OH with substituted halobenzenes are in the range (1.7 to 9.3) x 10 dm mol s. The rate constants obtained are found to follow the Hammett relationship for the reaction of OH with substituted halobenzenes and the p was found to be -0.5, indicating that OH radicals react by addition to the benzene ting. 

The spectra of the intermediate transients formed in the reaction of OH with dichloro- and dibromo-benzenes and chloro- and bromo-toluenes exhibited absorption maxima around 325-330 nm with both ortho- and w to-isomers of dichlorobenzenes, dibromobenzenes, and bromotoluenes (Fig. 6). The transients were assigned to the isomeric OH adducts formed from the addition of OH to the benzene ring. A blue shift was observed in the absorption maximum of -bromotoluene (315 nm) when compared to its ortho- and meta-isomers which have maxima at 330 nm. Such a behavior was also seen in the absorption spectra of OH adducts of 0- and w-chlorotoluenes (325-330 nm) and w-xylenes (326-328 nm) as compared to their... 

Beilstein Handbook Reference) AI3-14885 Benzene, 1-chloro-2-(chloromethyl)- BRN 0471700 1-Chloro-2-(chloromethyl)benzene 2-Chlorobenzyl chloride a,2-Dichlorotoluene a,o-Dichlorotoluene EINECS 210-258-8 NSC 8446 o-Chlorobenzyl chloride Ortho-a-dichlorotoluene Toluene, a,o-dichloro- Toluene, o,a-dichloro-. Liquid mp = -17° bp = 217° d° = 1.2699 Am = 271, 278 nm (s = 339, 263, MeOH) insoluble in H2O, slightly soluble in EtOH, CCU, soluble in CS2, very soluble in Et20, CeHe, AcOH,... 

Kodomari et al. [8] report the chlorination of alkoxybenzenes in chlorobenzene with copper(II) chloride on neutral alumina. The reactions are typically carried out at 100°C within 3 h, giving excellent yields and para to ortho product ratios greater than 30. Higher substituted arenes have been chlorinated with sulfuryl chloride and silica gel in hexane at room temperature [9]. 1,2,4,5-Tetramethylbenzene yields 73% of the mono-chloro product and 10% of the dichloro product. The system has been applied to a wide range of substituted benzenes and naphthalenes. 

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