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Material Safety Data Sheet(MSDS)

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• Chemical Properties

  Pure products are white crystal, odorless. m.p.174 ~ 178℃, decomposition temperature 192℃, vapor pressure 6.133x10-4Pa (25℃). Solubility in organic solvents: dichloromethane 102g/L, acetone 57g/L, methanol 14g/L, toluene 3g/L, hexane 10mg/L. Solubility in water at 25℃: 100~125mg/L (pH=4.1) and 27.9g/L (pH=7). Unstable in the acid condition, the circulating half-life of hydrolysis is 4~8 weeks when pH is 5.7～7 but 1 week when pH is 4. Under dry conditions, the photolysis of chlorsulfuron on plant surfaces is 30% within 30 days, and the photolysis of chlorsulfuron on soil surface is 15%. The circulating half-life in the soil is 4~6 weeks. ;

• Uses

  Intrinsic and super-efficient sulfonylurea herbicide. When absorbed by surfaces or roots of weeds, the agent is conducted to the whole plant. It inhibits the synthesis of branched chain amino acids, valine and leucine by inhibiting the activity of acetyl lactase, thereby stopping cell division, producing chlorosis and withering away to death. It is used to control broadleaf weeds and grass weeds in cereal crop fields, such as goosefoot, polygonum, amaranth, cleaver, piemarker, field bindweed, cirsium arvense, black bindweed, german camomile, setaria viridis, ryegrass, bluegrass, allium macrostemon bunge and so on. Not effective for avena fatua and solanum nigrum. It is used early before or after germination and usually administered after autumn crops are sowed but before germination or after germination of spring weeds. It is more suitable to provide leaf surface treatments after germination. Mix 0.15~0.6 grams of active ingredient per 100m2 with water to spray. It has good effects when mixed with chlortoluron and isoproteron. The crops such as corn, rape and so on are sensitive to the second stubble. It has little effect on the following rice when the dosage exceeds 0.6g.
  Chlorsulfuron is a new type of sulfonylurea herbicide developed by DuPont Company of America in 1978. DuPont has turned it into a commercial product from 1981. The product is a super-efficient herbicide with low toxicity characterized by high activity, broad spectrum, selective safety of wheat seedlings. ;

• Production

  • Preparation of 2-mino-4-methyl-6-methoxy symtriazine
  The craft process of isourea salt method is as followed: Mix 4.7g cyanamide (90%) with 4g water, add razoxane ethyl ethylimidoote hydrochloride(90%) at 10℃ and stir for 1h. Then use sodium hydroxide to adjust the pH value between 5 to 6 and stir for 1h at 5~10℃. Add 10ml water, stir to layer and obtain N-cyano ethyl ethylimidoote by reduced pressure distillation in oil layer with a yield of 91%. Mix 50g carbamide, 100g dimethyl sulfate and 32g methanol together, heat up it to 55℃slowly, turn off the heat, automatically reach to 60℃, cool it at 68℃ appropriately ,stop cooling at 83℃, continue to heat up to 113℃, then reduce to 105℃automatically and cool to 50℃ to obtain methyl isoureas aimethyl sulfate slat with a yield of 93%. Add 1.4g sodium in 25ml methanol, cool it to -10℃, add 11.2g methyl isoureas aimethyl sulfate slat(90%), drop 5.6g N-cyano ethyl ethylimidoote at a temperature within the range of 0℃ to 14℃, heat it up to 20℃, stir for 20h to obtain 2-mino-4-methyl-6-methoxy symtriazine by post-processing with a yield of 69.3%.
  Other synthetic methods can be found in the preparation of metsulfuron-methyl.
  • The preparation of N-chlorophenylsulfonyl isocyanate
  Mix 230ml concentrated hydrochloric acid, 70ml water and 121g o-chloroaniline together, and cool the mixture to -5℃. Add sodium nitrite solution(40%), keep the reaction temperature below 3℃, add excessive nitrite acid. At the end of the reaction, use a little urea to destroy the excess nitrite, and then remove the solid impurities to complete the diazotization of o-chloroaniline.
  Dissolve 198g sodium bisulfite in 350mL water, then divide the solution into 2 parts. One part is put into the reaction flask containing 770ml concentrated hydrochloric acid and 24g anhydrous copper sulfate. Add the other part and diazonium salt solution into the solution above at the same time under the conditions of mixed cooling. Keep the reaction temperature at 0℃, isolate the oil layer at the end of the reaction, wash with water to obtain o-chlorobenzenesulfonyl chloride. The conversion rate of the above two steps is 88.7%. Drop the o-chlorobenzenesulfonyl chloride into a reaction bottle containing 430ml concentrated ammonia water, control the bath temperature at 60℃ and keep the temperature for for 4h. After the filtration, water-dioxane(5:1) mixtures are used to recrystallize, and o-chlorobenzenesulfonamide is obtained after decolorizing with a yield of 63%.
  Mix 19.2g o-chlorobenzenesulfonamide, 150ml o-dichlorobenzene and 63.5g oxalyl chloride together, react for 9h to evaporate excess oxalyl chloride. Until the reaction temperature reaches 18℃, the o-dichlorobenzene is evaporated and N-chlorophenylsulfonyl is obtained by reduced pressure distillation with a yield of 57.3%. Phosgene can also be used to replace oxalyl chloride to synthesize cyanate ester in the presence of tertiary amine.
  • Synthesis of chlorsulfuron
  Mix 0.02mol 2-mino-4-methyl-6-methoxy symtriazine and 40ml anhydrous acetonitrile together, drop 0.02mol N-chlorophenylsulfonyl isocyanate acetonitrile solution into the mixture and then continue to stir at the room temperature for 24h. Sniff out white powders, wash with acetonitrile, dry to obtain chlorsulfuron products with a yield of 70%. Chlorsulfonide can also be prepared by the addition reaction of o-chlorobenzenesulfonamide with 4-methyl-6-methoxy symtriazine-2-isocyanate prepared by the reaction of 2-mino-4-methyl-6-methoxy symtriazine and phosgene. ;

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