Phenols 2,3-dichlorophenol

Dichlorophenols. Among all the dichlorophenols, C H Cl O, it is 2,4-dichlorophenol that is produced in greatest quantity. 2,4-Dichlorophenol is used in manufacturing 2,4-dichlorophenoxyacetic acid [94-75-7] (2,4-D) and 2-(2,4-dichlorophenoxy)propionic acid [720-36-5] (2,4-DP). Industrially, 2,4-dichlorophenol can be obtained by chlorinating phenol, -chlorophenol, o-chlorophenol, or a mixture of these compounds in cast-iron reactors. The chlorinating agent may be chlorine or sulfuryl chloride in combination with a Lewis acid. For example ... 

The guanidine function, when attached to an appropriate lipophilic function, often yields compounds that exhibit antihypertensive activity by means of their peripheral sympathetic blocking effects. Attachment of an aromatic ring via a phenolic ether seems to fulfill these structural requirements. Alkylation of 2,6-dichlorophenol with bromochloroethane leads to the intermediate, 58. Alkylation of hydrazine with that halide gives 59. Reaction of the hydrazine with S-methylthiourea affords the guanidine, guanoclor (60). ... 

In addition lo its use in making resins and adhesives, phenol is also the starting material for the synthesis of chlorinated phenols and the food preservatives BHT (butylated hvdroxytoiuene) and BHA (butylated bydroxyanisole). Penta-chlorophenol, a widely used wood preservative, is prepared by reaction of phenol with excess CI2- The herbicide 2,4-D (2,4-dichlorophenoxyacetjc acid) is prepared from 2,4-dichlorophenol, and the hospital antiseptic agent hexa-chlorophene is prepared from 2,4,5-trichlorophenol. 

Phenol 2,4,6-trichlorophenol p-chloro-m-cresol 2-chlorophe-nol 2,4-dichlorophenol 2,4,-dimethylphenol 2-nitrophenol 4-nitrophenol 2,4-dinitrophenol and pentachlorophenol... 

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. 

The reaction products from 2,4-dichlorophenol were tetrachloro-phenoxyphenols and tetrachlorodihydroxybiphenyls (Figure 5), as determined from their mass spectra and those of their methyl ethers. 4,6-Dichloro-2-(2, 4 -dichlorophenoxy)phenol (V) was the major phenoxy-phenol the mass spectral fragmentation pattern of o-hydroxyphenol ethers is quite characteristic since a hydrogen transfer occurs during the fragmentation (Figure 6). A trace of a trichlorophenoxyphenol also was detected and was formed presumably by the unsensitized reductive loss of chlorine, discussed previously. 

Plant uptake is one of several routes by which an organic contaminant can enter man s food chain. The amount of uptake depends on plant species, concentration, depth of placement, soil type, temperature, moisture, and many other parameters. Translocation of the absorbed material into various plant parts will determine the degree of man s exposure—i.e., whether the material moves to an edible portion of the plant. Past experience with nonpolar chlorinated pesticides suggested optimal uptake conditions are achieved when the chemical is placed in a soil with low adsorptive capacity e.g., a sand), evenly distributed throughout the soil profile, and with oil producing plants. Plant experiments were conducted with one set of parameters that would be optimal for uptake and translocation. The uptake of two dioxins and one phenol (2,4-dichlorophenol (DCP)) from one soil was measured in soybean and oats (7). The application rates were DCP = 0.07 ppm, DCDD 0.10 ppm, and TCDD = 0.06 ppm. The specific activity of the com-... 

Several facts have emerged from our studies with 2,7-DCDD and 2,3,7,8-TCDD. They are not biosynthesized by condensation of chloro-phenols in soils, and they are not photoproducts of 2,4-dichlorophenol. They do not leach into the soil profile and consequently pose no threat to groundwater, and they are not taken up by plants from minute residues likely to occur in soils. Photodecomposition is insignificant on dry soil surfaces but is probably important in water. Dichlorodibenzo-p-dioxin is lost by volatilization, but TCDD is probably involatile. These compounds are not translocated within the plant from foliar application, and they are degraded in the soil. 

The most convenient and successful synthetic preparation of octa-chlorodibenzo-p-dioxin has been described by Kulka (13). The procedure involves chlorination of pentachlorophenol in refluxing trichlorobenzene to give octachlorodibenzo-p-dioxin in 80% yield. Kulka has explained the reaction as coupling between two pentachlorophenoxy radicals. Large amounts (5—15%) of heptachlorodibenzo-p-dioxin were observed in the unpurified product. Since the pentachlorophenol used in this study contained 0.07% tetrachlorophenol, we feel that tetrachloro-phenol may be produced in situ (Reaction 4). Such a scheme would be analogous to the formation of 2,4-dichlorophenol and 3-chlorophenol produced from 2,4,4 -trichloro-2 -hydroxydiphenyl ether (Reaction 2). The solubility of octachlorodibenzo-p-dioxin was determined in various solvents data are presented in Table II. 

Although the results of experiments on the dechlorination of pentachlorophenol (Bryant et al. 1991) enabled elucidation of the pathways to be elucidated, this study also revealed one of the limitations in the use of such procedures. Detailed interpretation of the kinetics of pentachlorophenol degradation using dichlorophenol-adapted cultures was equivocal due to carryover of phenol from the sediment slurries. 

Both in situ microcosms and laboratory systems were used to compare and evalnate first-order rates of degradation for a range of mixed snbstrates inclnding aromatic hydrocarbons and phenolic compounds (Nielsen et al. 1996). The observed rates were comparable, althongh no systematic differences were observed with the exception of 2,6-dichlorophenol, which was not degraded in the laboratory system. 

A facultatively anaerobic organism designated Anaeromyxobacter dehalogenans (Sanford et al. 2002) was capable of dechlorinating ortho-chlorinated phenols using acetate as electron donor—2-chlorophenol was reduced to phenol and 2,6-dichlorophenol to 2-chloro-phenol (Cole et al. 1994). A strain of Desulfovibrio dechloracetivorans was also able to couple the dechlorination of ortho-substituted chlorophenols to the oxidation of acetate, fumarate, lactate, and propionate (Sun et al. 2000). 

Spain JC, GJ Zylstra, CK Blake, DT Gibson (1989) Monohydroxylation of phenol and 2,5-dichlorophenol by toluene dioxygenase in Pseudomonas putida FI. Appl Environ Microbiol 55 2648-2652. 

Organic carboxylic acids are commonly found in foods, in the adipate process stream, and as pollutants. Fatty acids are the lipophilic portion of glycerides and a major component of the cell membrane. Phenols are widely used in polymers, as wood preservatives, and as disinfectants. Chloro-phenols such as 4-chlorophenol, two isomeric dichlorophenols, 2,4,6-tri-chlorophenol, three isomeric tetrachlorophenols, and pentachlorophenol were separated on a Dowex (The Dow Chemical Co. Midland, MI) 2-X8 anion exchange resin using an acetic acid-methanol gradient.138... 

Another feature of the process is that the sorption capacity of type II organoclays is inversely related to the aqueous solubility of the NOCs (Chiou 1989). For example, the affinity of HDTMA-smectite for various phenols increases in the order phenol < chlorophenol < dichlorophenol < trichlorophenol since phenol is the most water-soluble while trichlorophe-nol is the most hydrophobic (Mortland et al. 1986, Lo et al. 1998). The relationship between the distribution (partition) coefficient in a type II organoclay and water-solubility is illustrated in Fig. 5 for a range of nonionic organic pollutants. 

Hodson, P.V., R. Parisella, B. Blunt, B. Gray, and K.L.E. Kaiser. 1991. Quantitative structure-activity relationships for chronic toxicity of phenol, p-chlorophcnol, 2,4-dichlorophenol, pentachlorophenol, p-nitro-phenol and 1,2,4-trichlorobenzene to early life stages of the rainbow trout (Oncorhynchus mykiss). Canad. Tech. Rep. Fish. Aquat. Sci. 1784. 56 pp. 

For on-site measurement from grab sampling, a compact optical device with disposable strips for BOD determination has been developed [36]. The system includes three pairs of light-emitting diodes and photodiodes, and the disposable strips are made of inexpensive, transparent polycarbonate plates, where Pseudomonas fluorescens is immobilized. Using the 2,6-dichlorophenol-indo-phenol sodium salt as chromophore, a linear relationship was observed between the bioluminescence of the exposed strip and the BOD value. 

Lee [42] determined pentachlorophenol and 19 other chlorinated phenols in sediments. Acidified sediment samples were Soxhlet extracted (acetone-hexane), back extracted into potassium bicarbonate, acetylated with acetic anhydride and re-extracted into petroleum ether for gas chromatographic analysis using an electron capture or a mass spectrometric detector. Procedures were validated with spiked sediment samples at 100,10 and lng chlorophenols per g. Recoveries of monochlorophenols and polychlorophenols (including dichlorophenols) were 65-85% and 80-95%, respectively. However, chloromethyl phenols were less than 50% recovered and results for phenol itself were very variable. The estimated lower detection limit was about 0.2ng per g. 

Fig. 20. A typical GC-MS trace of a phenol contaminated soil sample, Bitterfeld, Germany (after [254] with permission). Chlorophenols were extracted using ASE-SPME upper chromatogram, procedure B lower chromatogram, ASE conditions of water, 150°C, 15 min. Peak identifications (1) 2-chlorophenol, (2) 2,4-dichlorophenol, (3) 4-chlorophenol, (4) 4-chloro-3-methylphenol, (5) 2,3,5-trichlorophenol, (6) 2,4,6-trichlorophenol, (7) 2,3,4-trichlo-rophenol, (8) 2,3,4,6-tetrachlorophenol, (9) pentachlorophenol... 

An extracellular lactase enzyme, isolated from the fungus Rhizoctonia prati-cola, was shown to mediate cross-coupling between phenolic constituents of HS and 2,4-dichlorophenol formed during the decomposition of 2,4-D, thus leading to the incorporation of this xenobiotic into SP0M. 

Many chlorophenols are harmful and persistent. It is possible that these may be produced microbiologically in nature in view of the finding that a fungal chloroperoxidase halogenates phenol to yield monochlorophenols and the latter to give dichlorophenols. The sequence continues with producing trichlorophe-nols, tetrachlorophenols, and even pentachlorophenol [208]. 

EPA. 1988b. Computer printout (CIS) 1977 production statistics for chemicals in the Federal Register. 1979. Petition to remove ethylbenzene, phenol, 2,4-dichlorophenol, 2,4,5- trichlorophenol and pentachlorophenol from the 307(a)(1) list of toxic pollutants. US. Environmental Protection Agency. Fed Reg 44 64555-64559. 

Oxidation peak potentials of phenol derivatives were measured with cyclic voltammetry 0.53, 0.47, 0.47, 0.28, and 0.77 V vs. Ag/ AgCl for phenol, 2,6-dimethyl-, 2,6-diphenyl-, 2,6-dimethoxy-, and 2,6-dichlorophenol respectively. The oxidation potential of phenol and 2,6-dichlorophenol are relatively high and this high potential is one of the reasons why phenol and dichlorophenol could not he polymerized by the oxidation with copper catalyst or lead dioxide. On the other hand, for the electro-oxidative polymerization the potential can he kept slightly higher than the oxidation potential of phenols and the polymerization proceeds. 

Indenopyrene, see Indeno[l,2,3-crf pyrene l//-Indole, see Indole Indolene, see Indoline Inexit, see Lindane Inhibisol, see 1,1,1-Trichloroethane Insecticide 497, see Dieldrin Insecticide 4049, see Malathion Insectophene, see a-Endosulfan, p-Endosulfan Intox 8, see Chlordane Inverton 245, see 2,4,5-T lodomethane, see Methyl iodide IP, see Indeno[l,2,3-crf pyrene IP3, see Isoamyl alcohol Ipaner, see 2,4-D IPE, see Isopropyl ether IPH, see Phenol Ipersan, see Trifluralin Iphanon, see Camphor Isceon 11, see Trichlorofluoromethane Isceon 122, see Dichlorodifluoromethane Iscobrome, see Methyl bromide Iscobrome D, see Ethylene dibromide Isoacetophorone, see Isophorone a-Isoamylene, see 3-Methyl-l-butene Isoamyl ethanoate, see Isoamyl acetate Isoamylhydride, see 2-Methylbutane Isoamylol, see Isoamyl alcohol Isobac, see 2,4-Dichlorophenol Isobenzofuran-l,3-dione, see Phthalic anhydride 1,3-Isobenzofurandione, see Phthalic anhydride IsoBuAc, see Isobutyl acetate IsoBuBz, see Isobutylbenzene Isobutane, see 2-Methylpropane Isobutanol, see Isobutyl alcohol Isobutene, see 2-Methylpropene Isobutenyl methyl ketone, see Mesityl oxide Isobutyl carbinol, see Isoamyl alcohol Isobutylene, see 2-Methylpropene Isobutylethylene, see 4-Methyl-l-pentene Isobutyl ketone, see Diisobutyl ketone Isobutyl methyl ketone, see 4-Methyl-2-pentanone Isobutyltrimethylmethane, see 2,2,4-Trimethylpentane Isocumene, see Propylbenzene Isocyanatomethane, see Methyl isocyanate Isocyanic acid, methyl ester, see Methyl isocyanate Isocyanic acid, methylphenylene ester, see 2,4-Toluene-diisocyanate... 

Chlorophenol, see p-Bromophenol. Chlorobenzene. p-Chloronitrophenol, 2,4-D, 2,4-Dichlorophenol, Pentachlorophenol, Phenol, 2,4,5-T, Triadimefon... 

---