English Name: fenclorim Alias: 4,6 - dichloro - 2 - phenylpyrimidine Molecular Formula: C10H6Cl2N2 Molecular Weight: 225.07 CAS Number: 3740 - 92 - 9 Customs Code: 2933599099 Structural Formula: II. Physicochemical Properties **Appearance**: Colorless crystals **Density**: 1.5 g/cm3 **Melting Point**: 92 - 96.9 °C **Boiling Point**: 235.5 ± 33.0 °C **Vapor Pressure**: 0.012 Pa (at 20 °C) **Solubility**: At 20 °C, the solubility in water is 2.5 mg/L. It is soluble in acetone, cyclohexanone, dichloromethane, toluene, xylene, and slightly soluble in hexane, methanol, n - octanol, and isopropanol. **Stability**: Stable below 400 °C **Half - life in soil**: DT50 is 17 - 35 days III. Toxicity Information - Acute oral LD50 for rats: > 5000 mg/kg - Acute dermal LD50 for rats: > 2000 mg/kg - Acute inhalation LC50 (4 - hour) for rats: Approximately 2.9 mg/L air It has a slight irritating effect on rabbit skin, no irritating effect on eyes, and no skin sensitization effect on guinea pigs. IV. Uses Fenclorim is a pyrimidine - type herbicide safener. It can improve the selectivity of herbicides, protect the safety of crops and the environment, expand the application range, and eliminate the residue of herbicides in the soil. It is an ideal antidote for herbicides. It is usually used in combination with pretilachlor to protect wet - sown rice from the harm of pretilachlor. The general ratio of fenclorim to pretilachlor is 1:3 - 1:4, and in northern low - temperature areas, the recommended ratio is 1:3. 60% butachlor is formulated with 7% - 8% fenclorim. V. Safety Information **Dangerous Goods Mark**: Xn (Harmful), indicating harmful **Safety Terms**: S36/37, indicating wear appropriate protective clothing and gloves **Risk Terms**: R20 (Harmful by inhalation), indicating harmful by inhalation; R43 (May cause sensitization by skin contact), indicating may cause sensitization by skin contact.