| Description | Captafol appears as white, colourless to pale yellow, or tan (technical-grade) crystals or asa crystalline solid or powder, with a slight characteristic pungent odour. It is practicallyinsoluble in water but is soluble or slightly soluble in most organic solvents. Captafolreacts with bases, acids, acid vapours, and strong oxidisers. Captafol is a broad-spectrumnonsystemic fungicide that is categorised as a phthalimide fungicide based on its tetrahydrophthalimidechemical ring structure (other phthalimide fungicides include captanand folpet). It hydrolyses slowly in aqueous emulsions or suspensions but rapidlyin acidic and basic aqueous alkaline media. Captafol will not burn, but when heated todecomposition, it emits toxic fumes, including nitrogen oxides, sulphur oxides, phosgene,and chlorine.Captafol is effective for the control of almost all fungal diseases of plants except powderymildews and is widely used outside the United States for the control foliage andfruit disease on apples, citrus, tomato, cranberry, potato, coffee, pineapple, peanut, onion,stone fruit, cucumber, blueberry, prune, watermelon, sweet corn, wheat, barley, oilseedrape, leek, and strawberry. It is also used as a seed protectant in cotton, peanuts, and rice.Captafol is also used in the lumber and timber industries to reduce losses from wood rotfungi in logs and wood products. Formulations of captafol include dusts, flowables, wettables,water dispersibles, and aqueous suspensions. Mixed formulations include (captafol +)triadimefon, ethirimol, folpet, halacrinate, propiconazole, and pyrazophos. Captafol iscompatible with most plant-protection products, with the exception of alkaline preparationsand formulating material. |
| Chemical Properties | Captafol is a white crystalline solid. |
| Chemical Properties | yellow to off-white powder |
| Uses | Agricultural fungicide, especially for potatoes. |
| Uses | Captafol is used to control a wide range of fungal diseases onmany crops. |
| Uses | Captafol is a pesticide, belonging to thiophtalimidegroup. Occupational contact dermatitis was reportedin an agricultural worker who had multiple sensitizations. |
| Definition | ChEBI: A dicarboximide that captan in which the trichloromethyl group is replaced by a 1,1,2,2-tetrachloroethyl group. A broad-spectrum fungicide used to control diseases in fruit and potatoes, it is no longer approved for use in the European Community. |
| General Description | White crystalline solid with a slight, but pungent odor. Mp: 162°C. Practically insoluble in water. Only slightly soluble in organic solvents. Technical CAPTAFOL is a wettable light tan powder that is used as a fungicide. Inhaled dust irritates the respiratory tract. Irritates skin and damages eyes. Acute oral toxicity in humans is low. Not persistent in the environment (decomposes with a half-life of 11 days in the soil). Highly toxic to fish and other aquatic organisms. |
| Reactivity Profile | CAPTAFOL is non-flammable but, on heating, may decompose to generate toxic fumes, such as sulfur oxides, hydrogen sulfide, hydrochloric acid, and phosgene. Stable at room temperature when dry but readily hydrolysed, especially in an alkaline environment. CAPTAFOL and mixtures containing high concentrations of CAPTAFOL may react violently with alkali. Incompatible with acids, acid chlorides, acid anhydrides, and strong oxidizing agents. Sulfhydryl compounds such as glutathione and cysteine cause a rapid chemical decomposition. |
| Hazard | Absorbed by skin. Probable carcinogen. |
| Agricultural Uses | Fungicide: Captafol is a General Use Pesticide and used for the control of practically all forms of fungal diseases except powdery mildew. It is also used as a seed protectorant on cotton, rice and peanut crops. Not registered for use in the U.S. or in EU countries. There are 20 global suppliers. |
| Trade name | CAPTATOL®; CAPTOFOL®; CRISFOLATAN®; DIFOLATAN®[C]; DIFOCAP®[C]; DIFOSAN®; FOLCID®; HAIPEN®; KENOFOL®; MERPAFOL®; ORTHO® 5865[C]; PILLARTAN®; SANSEAL®; SANSPOR®; SANTAR-SM®; SULFONIMIDE®; SULPHEIMIDE® |
| Contact allergens | Captafol is a pesticide, belonging to thiophthalimidegroup. Occupational contact dermatitis was reported inan agricultural worker who had multiple sensitizations |
| Safety Profile | Confirmed carcinogen with experimental carcinogenic data. Poison by intraperitoneal route. Moderately toxic by ingestion. An experimental teratogen. Other experimental reproductive effects. Mutation data reported. A fungicide. When heated to decomposition it emits very toxic fumes of Cl-, NO,, and SOx |
| Potential Exposure | Captafol is a thiophthalimide fungicide. Those engaged in the manufacture, formulation, andapplication of this fungicide. Captafol is not currently registered for use on field crops or stored produce in theUnited States. |
| First aid | If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPRif heart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit. |
| Carcinogenicity | Captafol is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals and supporting data on mechanisms of carcinogenesis. |
| Environmental Fate | The primary toxicity following captafol exposure probablyoccurs through a hypersensitivity mechanism. Most experimentssuggest captafol to be DNA active. |
| Metabolic pathway | Captafol contains an unstable tetrachloroethylthio (sulfenyl) moiety thathas been shown to undergo rapid hydrolytic and metabolic degradationto tetrahydrophthalimide (2). By analogy with captan, presumably thetetrachloroethylthio moiety can be transferred to the sulfur atoms ofthiols such as cysteine and glutathone. Thus in the presence of thiolssuch as glutathione, captafol is probably cleaved at the N-S bond toform thiophosgene (3) and other gaseous products such as hydrogensulfide, hydrogen chloride and carbonyl sulfide. Thiophosgene is rapidlyhydrolysed by water. The tetrachloroethylthio group and thiophosgeneare believed to be intermediates in the formation of thiazolidine-2-thione-6carboxylic acid (4) which is an addition product with cysteine. Athiazolidine derivative of glutathione is also formed (5). Biotransformationof captafol in mammals generates primarily thiophosgene (3)and tetrahydrophthalimide (2). Tetrahydrophthalimide (2) and variousof its derivatives are excreted in the urine. There were no reports of2-thiazolidinethione-4-carboxylic acid (4) in the urine. |
| storage | Color Code—Green: General storage may be used.Prior to working with captafol you should be trained on itsproper handling and storage. Store in tightly closed containers in a cool, well-ventilated area away from heat, acids,acid fumes, or strong oxidizers (such as peroxides, chlorates, perchlorates, nitrates and permanganates), since violent reactions occur. A regulated, marked area should beestablished where this chemical is handled, used, or storedin compliance with OSHA Standard 1910.1045. |
| Shipping | UN2811 Toxic solids, organic, n.o.s., HazardClass: 6.1; Labels: 6.1-Poisonous materials, TechnicalName Required. UN 2773 Phthalimide derivative pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonousmaterials, Technical Name Required. |
| Degradation | Captafol is hydrolysed rapidly in acidic and alkaline conditions. Itdecomposes slowly at its melting point of 161 °C (PM). Captafol isdecomposed by base-catalysed hydrolysis with half-lives of 77.8, 6.54 and0.72 hours at pH 3,7 and 8, respectively (Kim et al., 1997)
In a study of aqueous photodegradation, a solution (MeCN/H2O 9:l)of unlabelled captafol (10 g l-1) was exposed to UV light for 4 days. Thereaction tube was encircled by low pressure Hg lamps giving more than85% of total radiation at 253.7 nm. Pure nitrogen was bubbled through thesolutions. Photo-oxidation studies were done similarly except that oxygenwas bubbled through the solution. In further experiments, irradiation wasby visible light from a tungsten lamp and again oxygen was bubbledthrough the solution. The outlet gases from the UV study were trapped insodium hydroxide solution and analysed by GC-MS. The main photoproductwas usually tetrahydrophthalimide (2). Analysis was by chromatographyand IR and NMR spectroscopy. Photolysis under nitrogen gave2 in 72% yield with elemental sulfur and HCl as the only products otherthan some parent captafol. Photooxidation of captafol gave tetrahydrophthalimide(2) in 78% yield together with sulfur dioxide, carbon dioxide,hydrogen chloride and some unreacted captafol. Oxidation of captafolin the presence of visible light together with Rose Bengal as a photosensitiseralso gave a high yield of tetrahydrophthalimide (2) and theother products obtained from photo-oxidation. Although the mechanismsof reaction were not studied, it is possible that sulfoxidised intermediatescould be involved in reactions with singlet oxygen. It was surprising that the cyclohexene moiety did not react with singlet oxygen and thatproducts of ring oxidation were not observed (Crank and Mursyidi, 1992). |
| Toxicity evaluation | Captafol is not persistent in the environment. Captafol is stableunder ordinary environmental conditions and rapidly degradesin soil, the rate of degradation being a function of soil type andpesticide concentration. It does not leach from basic soils and isunlikely to contaminate groundwater. Captafol sprayed onmost crops has a half-life of less than 5 days. Captafol and/or itsmetabolites and degradation products are readily absorbed byroots and shoots of plants. If released to air, an extrapolatedvapor pressure of 8.27×10-9 mm Hg at 25°C indicatescaptafol will exist solely in the particulate phase in the ambientatmosphere. Particulate-phase captafol will be removed fromthe atmosphere by wet and dry deposition. If released to soil,captafol is expected to have slight mobility based on Koc valuesof 2073 and 2120. Volatilization from moist soil surfaces is notexpected to be an important fate process based on a Henry’sLaw constant of 2.7×10-9 atm-cu m mol-1. In a laboratorysetting, the biodegradation half-life of captafol in three soilswas found in the range of 23–55 days. The overall half-life ofcaptafol in soil is about 11 days, independent of soil type orinitial concentration. If released into water, captafol is expectedto adsorb to suspended solids and sediment based on the Koc.Volatilization from water surfaces is not expected to be animportant fate process based on this compound’s estimatedHenry’s Law constant. An estimated bioconcentration factor of170 suggests the potential for bioconcentration in aquaticorganisms is high, provided the compound is not alteredphysically or chemically after being released to the environment. The half-lives for the hydrolysis of Difolatan atpH 3.0, 7.0, and 8.0 were 77.8, 6.54, and 0.72 h, respectively.Hydrolysis is likely to be the predominant pathway of degradationin the aquatic environment. |
| Incompatibilities | Reacts violently with bases, causing fireand explosion hazard. Not compatible with strong acids oracid vapor, oxidizers. Strong alkaline conditions contributeto instability. Attacks some metals. |
| Waste Disposal | Hydrolysis. |
