- Aqueous chlorination kinetics and mechanism of substituted dihydroxybenzenes
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The initial chlorination kinetics of several substituted dihydroxybenzenes, including chlorinated resorcinol compounds, was studied over the pH range of 2-12 at 22 °C. For each of the resorcinol substrates, the apparent chlorination rates are a minimum in the pH range of 3-6 and a maximum at pH values between 8-11. A mechanism that involves the reaction of HOCl with ArX(OH)2, ArX(OH)O-, and ArX(O-)2, and an acid-catalyzed pathway at pH 2, ArX(OH)O-, and ArX(O-)2, and an acid-catalyzed pathway at pH 4 was proposed to explain this pH dependence. Over natural water pH conditions, the reactions of HOCl with the anion and dianion forms of resorcinol groups are the most important. Although the intrinsic reactivity of HOCl with resorcinol substrates decreases with the extent of chlorine substitution on aromatic ring, the apparent reactivity of HOCl increases for more chlorinated resorcinols. In the presence of excess HOCl, monochloro- and dichloro resorcinol intermediates, therefore, should not accumulate when resorcinol groups undergo chlorine substitution. Linear free energy relationships for the reactivity of HOCl with resorcinols and phenols were developed. The sequential chlorination kinetics of resorcinol up to trichlororesorcinol can now be modeled.
- Rebenne, Laurence M.,Gonzalez, Alicia G.,Olson, Terese M.
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p. 2235 - 2242
(2007/10/03)
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- Properties of chlorinated dihydroxybenzenes - components of pulp bleaching effluents
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Gas chromatography and mass spectrometry data are given for the chlorodihydroxybenzenes which are components of wood pulp bleaching effluents and biologically-treated effluents, and are proposed intermediates in the chlorination of humic acids. The chlorohydroxybenzenes include the nine chlorocatechols, the six chlorohydroquinones and the seven known chlororesorcinols. The 22 chlorinated compounds were generally well separated on a phenyl methyl silicone column with the exception of three dichloro compounds. The chloro compounds with the same level of chlorine substitution were not able to be distinguished on the basis of their electron impact mass spectra.
- Smith, Terrence J.,Wearne, Ross H.,Wallis, Adrian F. A.
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p. 1555 - 1560
(2007/10/03)
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- SYNTHESIS OF SULFONIUM CHLORIDES FROM THIOPHANE, PHENOLS, AND CHLORINE
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A one-stage synthesis was realized for 2(3)-methyl-4-hydroxy-, 2,4-dihydroxy-, 2,3,4-trihydroxy-, and 2,5-dihydroxyphenylthiophanium chlorides by the reactions of substituted phenols with thiophane and chlorine.The yields (57-75percent) of the products varied in line with the activity of the phenols.
- Sakharova, S. N.,Karaulova, E. N.,Krapivin, A. M.,Gal'pern, G. D.
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p. 1513 - 1516
(2007/10/02)
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