Mefenpyr - diethyl I. Basic Information English Name**: mefenpyr - diethyl Molecular Formula**: C16H18Cl2N2O4 Molecular Weight**: 373.2311 CAS Number**: 135590 - 91 - 9 Customs Code**: 2933199090 Chinese Alias**: (RS)-1-(2,4 - dichlorophenyl)-5 - methyl - 2 - pyrazoline - 3,5 - dicarboxylic acid diethyl ester Structural Formula** II. Physicochemical Properties Appearance**: Grayish - white to light beige powder Melting Point**: 50 - 52°C Boiling Point**: 451.1 ± 55.0°C (Predicted) Density**: 1.34 ± 0.1 g/cm3 (Predicted) Vapor Pressure**: 0 - 0.001 Pa at 20 - 50°C Flash Point**: 226.6 ± 31.5°C III. Storage Method Store in a sealed container at 0 - 6°C. IV. Main Uses Mefenpyr - diethyl is a broad - spectrum pesticide. When mixed with herbicides, it has higher activity and better detoxification ability compared with other safeners. It improves the crop's tolerance to herbicides by enhancing the metabolism of herbicides in cereal crops, thus ensuring the safety of herbicides to crops. Common herbicides formulated with mefenpyr - diethyl include (R)-fenoxaprop - P - ethyl (3:11), iodosulfuron - methyl - sodium, mesosulfuron - methyl (1:3), clodinafop - propargyl (1:4), pyrazosulfuron - ethyl, florpyrauxifen - benzyl, and pyroxsulam (1:1), etc. V. Safety Information **R51/53**: Toxic to aquatic organisms, may cause long - term adverse effects in the aquatic environment. **S60**: This substance and its container must be disposed of as hazardous waste. **S61**: Avoid release to the environment. Refer to special instructions/safety data sheets. VI. Main Proportions In Imtrade Maddog Selective Herbicide, the volume ratio of (R)-fenoxaprop - P - ethyl to mefenpyr - diethyl is 11:3; in Hussar?, the volume ratio of iodosulfuron - methyl - sodium to mefenpyr - diethyl is 1:3; in Atlantis?, the volume ratio of mesosulfuron - methyl to mefenpyr - diethyl is 1:3. There is no fixed ratio for the dosage of herbicides and mefenpyr - diethyl. Generally, the dosage of mefenpyr - diethyl required to ensure the safety of herbicides is 20 - 100 g a.i./hm2. There are the following problems in the process of using mefenpyr - diethyl in combination with herbicides: (1) Mefenpyr - diethyl has a protective effect on Aegilops tauschii, the target weed of mesosulfuron - methyl, and can improve its tolerance, reducing the control effect of mesosulfuron - methyl on Aegilops tauschii. Therefore, a synergistic adjuvant needs to be added to the mature mesosulfuron - methyl formulation. (2) The absorption site and conduction direction of the compound in plants are highly specific. Currently, mefenpyr - diethyl exerts its effect through foliar spraying absorption, and there is no report on whether mefenpyr - diethyl is effective when used on other parts of crops. (3) The melting point of the technical mefenpyr - diethyl is 50 - 52°C, which belongs to a low - melting - point technical drug. After being made into a suspension concentrate, problems such as delamination, solidification, and a decrease in the suspension rate are likely to occur.