The invention relates to a method for synthesizing o-
methyl formate benzene sulfonamide which is capable of effectively solving the problems that a conventional o-
methyl formate benzene sulfonamide synthesizing method is complex in process, high in cost, low in efficiency and pollutes environment and comprises the steps of: heating water, adding
sodium nitrite, dissolving, and adding methyl o-aminobenzoate to obtain a methyl ester mixture; putting the water in a
diazo pot, adding
sulfuric acid and
hydrochloric acid to obtained mixed acid; reducing the temperature of the mixed acid, adding the methyl ester mixture, reacting to obtain a diazonium
salt solution, adding
copper sulfate, introducing
sulfur dioxide, determining by utilizing an H acid
reagent solution and
fading by utilizing the H acid; adding
toluene, introducing
liquid chlorine, determining to be darkgreen by utilizing a
benzidine reagent solution, standing and layering to obtain an o-
methyl formate benzene sulfonamide solution at the upper layer; and adding
anhydrous toluene and carbinol, introducing
liquid ammonia, adjusting pH (potential Of
Hydrogen) value to be neutral by using
acetic acid, removing the
acetic acid, washing till being colourless by using the
toluene, removing the toluene, beating by using the water, washing to be neutral, removing the water and
drying. The method disclosed by the invention has the advantages of easiness in operation, high efficiency, low cost and good quality, and saves energy and
raw material, and is environment-friendly.