The invention discloses a process for producing thiabendazole. The process includes carrying out
condensation reaction on
lactic acid and o-phenylenediamine in acidic
aqueous solution(with, but not limited to,
hydrochloric acid); regulating pH (potential of
hydrogen) values to obtain 2-alpha-hydroxyl ethyl
benzimidazole; placing the 2-alpha-hydroxyl ethyl
benzimidazole in a container with
acetone and
sulfuric acid (but not limited to
sulfuric acid, or
hydrochloric acid and other inorganic acid and strong acid and weak
alkali salt) and carrying out oxidation reaction on the 2-alpha-hydroxyl ethyl
benzimidazole and
potassium permanganate (but not limited to
potassium permanganate, or
hydrogen peroxide and
organic peroxide); carrying out extraction,
desolvation and
drying to obtain 2-acetyl benzimidazole; placing the 2-acetyl benzimidazole in a container with glacial
acetic acid and carrying out halogenations reaction on the 2-acetyl benzimidazole and
bromine (but not limited to, or
chlorine and other halogens);
drying filter cake to obtain 2-
dibromomethane acetyl benzimidazole
hydrobromide; carrying out reaction on
formamide and
phosphorus pentasulfide in a container with
ethyl acetate to obtain thioformamide; removing
phosphorus pentoxide by means of filter-press by the aid of
nitrogen to obtain thioformamide /
ethyl acetate solution and carrying out cyclization reaction on the thioformamide /
ethyl acetate solution and 2-
dibromomethane acetyl benzimidazole; purifying reaction products and regulating pH (potential of
hydrogen) values to obtain the thiabendazole with the content higher than or equal to 99%. The
acetone and the
sulfuric acid in the corresponding container are used as solvents. The glacial
acetic acid in the corresponding container is used as a
solvent. The ethyl acetate in the corresponding container is used as a
solvent. The process has the advantages that the cost can be lowered, risks in the aspects of safety and
environmental protection can be reduced, environmental
pollution can be abated, and the production efficiency can be improved; integral reaction procedures are carried out at the normal temperatures under the normal pressures, accordingly,
reaction conditions are mild, the yield of the reaction at each step is quite stable, and the overall yield measured by the aid of the o-phenylenediamine can reach 75% at least.