3-chloro-2-aminotoluene (3-Chloro-2-methylaniline) is a kind of important pesticide intermediate, can be used to synthetic hormone type quinoline carboxylic acid weedicide. This weedicide is widely used before the bud in direct seeding rice fields or transplanting rice fields and weeding behind the bud; it can effectively prevent and kill off multiple weeds, such as barnyard grass and Herba Aeschynonenes Indicae. 3-Chloro-2-methylaniline is the raw material of synthetic quinclorac, and the height of its purity directly influences yield, content and the drug effect of synthetic quinclorac.

An invention discloses a synthetic method of 3-chloro-2-methylaniline, which comprises the following steps: dissolving polysulfide in water, stirring, adding ammonium salts, heating, controlling the temperature to be 30-105 DEG C, adding dropwisely 6-chloro-2-nitrotoluene to perform a reaction; after the reaction, separating the organic phase, washing with water to neutrality, performing distillation of the organic phase with a vacuum degree of 0.1 MPa, collecting fractions at 127-137 DEG C to obtain 3-chloro-2-methylaniline. The synthetic method of 3-chloro-2-methylaniline of the invention has a high yield, low production cost, and high security.

In 1000 milliliters, the there-necked flask that mechanical stirring, reflux condensing tube, and thermometer are housed, the sodium polysulphide of 50ml water and 1mol is added flask, mix objects system and add the 0.4mol brome to de amnio again, progressively drip 1mol 6-chloro-2-nitrotoluene after the intensification, the temperature is controlled at 30 ℃, and following chemical reaction takes place system:

After the reaction is finished, tell the organic phase on the upper strata, be washed to neutrality, the organic phase is distilled, and vacuum tightness 0.1MPa collects 127～137 ℃ of fractions, 139.8 grams. 3-Chloro-2-methylaniline purity is 99.80% in the fraction, which calculates a yield of 98.80% with 6-chloro-2-nitrotoluene.