Chemical Fact Sheet

Chemical Abstract Number (CAS #) 120832
CASRN 120-83-2
Phenol, 2,4-dichloro-
Analytical Methods EPA Method 604
EPA Method 625
EPA Method 8040
EPA Method 8270
Molecular FormulaC6H4Cl2O

Link to the National Library of Medicine's Hazardous Substances
Database for more details on this compound.

Use IN SYNTHESIS OF ANTIHELMINTHIC BITHIONOL SULFOXIDE CHEM INT FOR HERBICIDES SUCH AS 2,4-DICHLOROPHENOXYACETATE, BIFENOX & DICHLORPROP HERBICIDES, 4-(2,4-DICHLOROPHENOXY)BUTYRATE HERBICIDE 2,4-DCP is used as a feedstock for the manufacture of certain methyl cmpd used in mothproofing, antiseptics & seed disinfectants. 2,4-DCP is also reacted with benzene sulfonyl chloride to produce miticide or further chlorinated to pentachlorophenol, a wood preservative.
Odor Strong medicinal
Boiling Point 210 DEG C
Melting Point 45 DEG C
Molecular Weight 163.00
Density 1.383 AT 60 DEG C/25 DEG C
Odor Threshold Concentration Odor detection in water: 2.10X10-1 ppm (chemically pure) In air: 0.21 ppm Purity not specified Detection in water: 0.04 mg/l; 0.002 mg/l; 0.0003 mg/l Purity not specified In air: low 1.4007 mg/cu m; high 1.4007 mg/cu m Purity not specified
Sensitivity Data Chlorinated benzenes are irritating to the skin, conjunctiva, and mucous membranes of the upper respiratory tract. Chlorinated benzenes
Environmental Impact 2,4-Dichlorophenol may be released to the environment in effluents from its manufacture and use as a chemical intermediate and from chlorination processes involving water treatment and wood pulp bleaching. Releases can also occur from various incineration processes or from metabolism of various pesticides in soil. If released to the atmosphere, degradation can occur by reaction with photochemically formed hydroxyl radicals (estimated avg half-life of 5.3 days). Physical removal from air may occur via rainfall. With a pKa of 7.8, 2,4-dichlorophenol can exist in both the non-dissociated and ionized forms in environmental soil and water depending upon the pH of the media. If released to soil, moderate to slow leaching is possible based on observed Koc values of 200-5000; the ionized form appears more susceptible to leaching than the non-dissociated form. Various biodegradation studies have demonstrated that 2,4-dichlorophenol is biodegradable under aerobic and anaerobic conditions in both soil and water. If released to water, adsorption to sediments may be important under various conditions determined, in part, by pH. Photodegradation in natural water can occur by direct photolysis or by reaction with sunlight-formed oxidants (singlet oxygen and peroxy radicals). The general population can be exposed to 2,4-dichlorophenol through consumption of contaminated tap water or by inhalation of contaminated air.
Environmental Fate TERRESTRIAL FATE: Contamination of soil in the vicinity of two Finnish sawmills using preservative (Ky-5) against blue-staining fungi that contained chlorophenols was studied. The soil around the treatment basins contained up to 70 mg chlorophenols/kg and that in the storage area for treated lumber up to 6 mg/kg. Contamination extended to a depth of at least 2 m near the treatment basins. Surface water inside the sawmill area contained the same chlorophenols as those used in wood preservation, plus some additional isomers. The ground water and lake water around the sawmill areas were contaminated. The fate of different chlorophenols in soil is probably affected by many factors, such as the water solubility of each chlorophenol, pH of the soil, rainfall, soil organic matter content, type and particle size of the soil, biological and photodegradation and the evaporation of each chlorophenol. Chlorophenols AQUATIC FATE: The consequences of contamination of the aquatic environment by chlorophenols including 2,4-dichlorophenol/, have been evaluated by extensive review of the available scientific data. The chlorophenols generally exert moderate toxic effects to mammalian and aquatic life, although toxicity to fish upon long-term exposure may be considerable, as has been found for 2,4-dichlorophenol. Persistence is low when adapted microflora is present, capable of biodegrading these compounds, but may become moderate to high depending on the environmental conditions. Bioaccumulation is expected to be low. A striking feature of these chlorophenols is their strong organoleptic effect. Chlorphenols Pseudomonas strains capable of mineralizing 2,4-dichlorophenol (DCP) and p-nitrophenol in culture media were isolated from soil. One DCP-metabolizing strain mineralized 1.0 and 10 ug of DCP but not 2.0 to 300 ng/ml in culture. When added to lake water containg 10 ug of DCP per ml, the strain mineralized DCP only after 6 days. The strain did not grow or metabolize DCP when inoculated into sterile lake water, but did so when the system was amended with glucose. The bacterium grew in sterile DCP-amended sewage, although not causing appreciable mineralization of the test compound. A second DCP-utilizing pseudomona failed to mineralize DCP when added to the surface of sterile soil, although activity was evident if the inoculum was mixed with the soil. TERRESTRIAL FATE: The adsorption of 2,4-dichlorophenol by soil material depends, in part, upon the pH of the soil(1,2,3). With a pKa of 7.8 , 2,4-dichlorophenol can exist in environmental media in both the non-dissociated and ionized forms. In highly alkaline soils (pH 10), it will be primarily in the ionized form and has been observed to be poorly adsorbed to soil under such conditions . Non-dissociated 2,4-dichlorophenol is expected to undergo more adsorption than the ionized form(1,2). Soil Koc values ranging from 200-5000 have been observed , indicating that either moderate leaching or virtually no leaching are possible depending on local conditions. Various biodegradation studies have demonstrated that 2,4-dichlorophenol is biodegradable under both aerobic and anaerobic conditions. Biodegradation may be the most important environmental dissapative process in soil. AQUATIC FATE: With a pKa of 7.8, 2,4-dichlorophenol can exist in both the non-dissociated and ionized forms in environmental waters depending upon the pH of the water. Under highly alkaline conditions (pH 10), the ionized form has been observed to be poorly adsorbed to soil materials , which suggests that the ionized form may not partition from the water column to aquatic sediments. Sediment Koc values of 266-3990 have been observed for the non-dissociated form(2,3), suggesting adsorption may be important. Evidence exists that supports enzymatic coupling of certain xenobiotic pollutants to humic substances is an important natural process . In one monitoring study, the concn of 2,4-dichlorophenol was found to be much greater in the aquatic sediments than in the associated water column . AQUATIC FATE: Photodegradation in surface water is likely to be important; photolysis half-lives of 0.7-3.0 hr have been reported for winter-summer conditions at the water surface ; these half-lives will increase significantly with an increase in water depth. Half-lives of 62 and 69.3 hr can be estimated for reaction with singlet oxygen and peroxy radicals (sunlight formed oxidants) in natural water under midday sunlight(2,3,SRC). Various biodegradation studies have shown that 2,4-dichlorophenol is degradable under both aerobic and anaerobic conditions. Aquatic hydrolysis and volatilization are not expected to be important. ATMOSPHERIC FATE: Based on a vapor pressure of 0.075 mm Hg at 25 deg C(1,SRC), 2,4-dichlorophenol can be expected to exist almost entirely in the vapor-phase in the ambient atmosphere(2,SRC). Vapor-phase 2,4-dichlorophenol is degraded in the ambient atmosphere by reaction with photochemically formed hydroxyl radicals; the half-life for this reaction in typical air can be estimated to be about 5.3 days(3,SRC). Direct photolysis in air may be possible, but kinetic rate data specific to air are not available to predict its relative significance. 2,4-Dichlorophenol has been detected in rainwater from Portland and Beaverton, OR(4,5); therefore, physical removal from air by means of wet deposition may have some importance. Atmospheric Fate: The atmospheric half-life of 2,4-dichlorophenol for the oxidation of vapor-phase by photochemically generated hydroxyl radicals is approximately 7 days. This value was calculated using estimated reaction rate constants of 1.53x10-12 cu m molecule-sec for 2,4-dichlorophenol at 25 deg C and an ambient hydroxyl radical concn of 8.0x10 5 molecules/cu m. Moist soil incubation with 2,4-dichlorophenol showed more decomposition in clay and sandy loam, than in clay loam. Small amounts of dichloroanisole were formed.
Drinking Water Impact CHLOROPHENOLS IN SEWAGE, STREAM WATER & TAP WATER IN THE VICINITY OF SEOUL, KOREA FROM JAN TO SEPT, 1979 WAS STUDIED. CHLORINATED PHENOLS CAN BE PRODUCED BY THE CHLORINATION OF PHENOL WITH HYPERCHLORITE IN WATER. CHLOROPHENOLS IDENTIFIED FROM TAP WATER IN SEOUL DURING THE SUMMER OF 1979 WERE: O-CHLOROPHENOL 0.042 PPB; 2,6-DICHLOROPHENOL 0.033 PPB; 2,4-DICHLOROPHENOL 0.003 PPB. DRINKING WATER: Based on federal studies of finished drinking waters, 2,4-dichlorophenol has been found in 17.2% of the groundwater supplies . 2,4-Dichlorophenol was detected in 8 raw water samples and 26 treated water samples (out of a total of 480 samples) collected at 40 potable water treatment facilities in Canada between Oct 1984 and July 1985 ; max concn of 17 and 72 ng/l were found in raw and treated water, respectively . SURFACE WATER: An analysis of the USEPA STORET Database determined that 2,4-dichlorophenol was positively detected in 0.4% of 876 effluent reporting stations at a median level below 10 ppb . 2,4-Dichlorophenol (plus 2,5-dichlorophenol) levels of 1.8 ug/kg were detected in water samples taken from the Weser estuary in Germany on Aug 21, 1978 . A 2,4-dichlorophenol level of 0.45 ppb was found in the Rhine River in 1978 . Max levels of 0.59 and 0.35 ppb were detected in the Rhine at Lobith, Netherlands in 1976 and 1977, respectively . GROUND WATER: 2,4- Dichlorophenol was detected in 6 of 10 groundwater samples (concn of 3.2-79.7 ppb) taken from two wells (between Oct 1981 and Mar 1983) in the vicinity of an abandoned creosote facility in Conroe, TX . 2,4-Dichlorophenol was detected in groundwater associated with an Australian quarry receiving organic waste dumping . SEAWATER: Seawater from the Gulf of Bothnia (Sweden) was found to contain 2,4-dichlorophenol levels of 2-400 ng/l from samples collected on Sept 13, 1982 and Nov 3, 1983 ; the presence of chlorophenols in the seawater was attributed to effluent discharges from a sulfate pulp mill . RAIN/SNOW: An average 2,4-dichlorophenol concn of 1.3 ng/l (range of 0.56-2.5 ng/l) was detected in rainwater of Portland, OR during monitoring between Feb and Apr 1984 . Levels of 0.55-20 ng/l were detected in rainwater collected in suburban Beaverton, OR in Feb and Apr 1982 . EFFL: 2,4-DICHLOROPHENOL IS A MAJOR COMPONENT OF PULP MILL EFFLUENTS FORMED DURING THE MULTI-STEP BLEACHING OF CELLULOSE TO REMOVE COLORED LIGNIN CONSTITUENTS. An analysis of the USEPA STORET Database determined that 2,4-dichlorophenol was positively detected in 3.0% of 1319 effluent reporting stations at a median level below 10 ppb . 2,4-Dichlorophenol levels of 2-11 ng/l were detected in waste liquors from Finnish pulp mills in 1983 ; levels of 234 and 570 ng/g were found in combustion ash from two municipal refuge incinerators . A 2,4-dichlorophenol concn of 0.1 ng/g was detected in particle effluents from coal-fired power plants . Combustion effluents from the combustion of municipal solid waste, wood wastes, and peat have been found to contain 2,4-dichlorophenol .

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