Trichloro phenol

Chlorinated dibenzo ip-dioxins are contaminants of phenol-based pesticides and may enter the environment where they are subject to the action of sunlight. Rate measurements showed that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is more rapidly photolyzed in methanol than octachlorodi-benzo-p-dioxin. Initially TCDD yields 2,3,7-trichlorodiben-zo-p-dioxin, and subsequent reductive dechlorination is accompanied by ring fission. Pure dibenzo-p-dioxin gave polymeric material and some 2,2 -dihydroxybiphenyl on irradiation. Riboflavin-sensitized photolysis of the potential precursors of dioxins, 2,4-dichlorophenol and 2,4,5-trichloro-phenol, in water gave no detectable dioxins. The products identified were chlorinated phenoxyphenols and dihydroxy-biphenyls. In contrast, aqueous alkaline solutions of purified pentachlorophenol gave traces of octachlorodibenzo-p-dioxin on irradiation. 

It would be diflBcult to estimate the quantity of TGDD which enters the environment each year. In addition to the common pesticides listed in Table I, other chlorophenols nd their derivatives are used widely. For example, large amounts of the disinfectant, hexachlorophene (2,2 -methylenebis(3,4,6-trichlorophenol)), are used in homes, hospitals, and industry, and the Dowcides 2 and B (2,4,5-trichlorophenol and its sodium salt) are industrial microbiocides. More than 50,000,000 lbs of trichloro-phenol are made in the United States each year (24), and much of it eventually must be dispersed in the environment. The dioxin content seems to be variable but is generally below 0.5 ppm (25). 

Wieser M, B Wagner, J Eberspacher, F Lingens (1997) Puriflcation and characterization of 2,4,6-trichloro-phenol-4-monooxygenase, a dehalogenating enzyme imm Azotobacter sp. strain GPL J Bacterial 179 202-208. 

Trichloro phenol prochloraz 1.2.3 Trichloro propylene diallate... 

GC-MS and HPLC analyses of electrolyzed solutions allowed the detection of aromatic intermediates such as p-benzoquinone and nitrobenzene for aniline, 4-chlorocatechol for 4-chlorophenol, 4-chlorophenol, 4-chlorocatechol, hydroquinone, and p-benzoquinone for 4-CPA, 4-chloro-o-cresol, mehylhy-droquinone, and methyl-p-benzoquinone for MCPA, 2,4-dichlorophenol, 4,6-dichlororesorcinol, chlorohydroquinone, and chloro-p-benzoquinone for 2,4-D, and 2,4,5-trichloro-phenol, 2,5-dichlorohydroquinone, 4,6-dichlororesorcinol, and 2,5-dihydroxy-p-benzoquinone for 2,4,5-T. In general, these by-products persisted in solution while the initial pollutant was degraded. 

Remarks. The action of free chlorine on phenol is so vigorous that trichloro-phenol is formed at once. Monochlorophenol can ako be prepared by adding the calculated quantity of sodium hypochlorite solution to a cold solution of phenol in sodium hyproduct obtained by this method, however, is chieffy o-chlorophenol. 

Figure 9. Total ion current chromatograms of animal urine extracts containing (A) 2,4-D, (B) 2,4,5-T, and (C) 2,4,5-trichloro-phenol and an isomer of trichlorodihydroxybenT ene, peak 2 (as ethyl esters and mono- and diethyl ethers, respectively) Programmed temperature conditions five minutes at 180°C, to 220°C at 5°Cfmin, isothermal at 220°C...

Glucuronide conjugates of pentachlorobenzene were observed following the initial phenol formation from hexachlorobenzene in rainbow trout (Oncorhynchus mykiss) fry following dietary exposure27. Other metabolites included traces of 2,5-dichloro-, 2,3,6-trichloro- and 2,4,5-trichloro-phenol. The biotransformation of pentachlorophenol... 

The formation of phenoxyphenols 8 and 2 at 70°C, which was only observed with the mixture of tetrachlorocyclohexadienone, 2,4,6-trichloro-phenol (Table 4) seemed to be a transformation of the 2,4,6-trichlorophenol catalysed by tetrachlorocyclohexadienone. 

Dioxins are chemical contaminants produced during the synthesis of chlorophenols and certain other halogenated aromatic hydrocarbons. There are 75 dioxin isomers of which 2,3,7,8 tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is the most toxic in animal studies (1 ). Table I illustrates some major substances contaminated with isomers of dioxin. These manufactured products include 2,4,5-trichloro-phenol (TCP) and its derivatives, such as 2,4,5-trichlorophenoxy-acetic acid (2,4,5-T), which are contaminated with 2,3,7,8-TCDD, as well as pentachlorophenol, which is contaminated with hexa-, hepta-, and octachlorinated isomers of dioxin. 

Kimmig J and Schulz KH Occupational chloracne caused by aromatic cyclic ethers. Dermatologies 115 540-546, 1957. Goldman PJ Critically acute chloracne caused by trichloro-phenol decomposition products. Arbeitsmed Sozialmed Arbeit-shygiene 7 12-18, 1972. 

A further technical manufacturing process from sodium-2,4,5-trichloro-phenolate and monochloroacetic acid in solvent medium has been developed too. 

Methylchlorofon 3-Methylcholanthrene 4,4 -Hethylenebis(2>chloroaniline) 2,2 -Methylenebis (3,4,6-trichloro-phenol)... 

Dichlorophenol containing a little tetra n-butylammonium chloride was treated with chlorine at 70C to give 2,4,6-trichloro-phenol. 

Figure 2. Photolysis of 2,4-dichlorophenol end 2,4,5-trichloro-phenol in estuarine water.

For example, while PhOH always means phenol, ArOH could mean phenol, 2,4,6-trichloro-phenol (the antiseptic TCP), paracetamol, or aspirin (among many other substituted phenols). Like R, the wild card alkyl group, Ar is a wild card aryl group. 

Minimum inhibition concentrations of 2,4,6-trichloro-phenol in nutrient media (mg/litre) ... 

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