Thiodicarb 95%TC Molluscicides Agrochemicals CAS 59669-26-0 White
Common name thiodicarb (BSI, draft E-ISO, (m) draft F-ISO, ANSI)
IUPAC name 3,7,9,13-tetramethyl-5,11-dioxa-2,8,14-trithia-4,7,9,12-tetra-azapentadeca-3,12-diene-6,10-dione
Chemical Abstracts name dimethyl N,N'-[thiobis[(methylimino)carbonyloxy]]bis(ethanimidothioate)
CAS RN [59669-26-0] EEC no. 261-848-7 Development codes CGA 45156 (Ciba-Geigy); UC 80 502; UC 51762 (both Union Carbide); RPA 80600 M (Rhône-Poulenc) Official codes AI3-29311; OMS 3026
Composition Tech. grade is 96% pure. Mol. wt. 354.5 M.f. C10H18N4O4S3 Form Colourless crystals; (tech., pale tan crystals). M.p. 173-174 ºC V.p. 5.7 mPa (20 ºC) KOW logP = 1.62 Henry 4.31 ´ 10-2 Pa m3 mol-1 (calc.) S.g./density 1.44 g/ml (20 ºC) Solubility In water 35 mg/l (25 ºC). In dichloromethane 150, acetone 8,
methanol 5, xylene 3 (all in g/kg, 25 ºC). Stability Stable at pH 6, rapidly hydrolysed at pH 9 and slowly at pH 3 (DT50
c. 9 d). Aqueous suspensions are decomposed by sunlight. Stable up to
Biochemistry Cholinesterase inhibitor. Mode of action Insecticide with predominantly stomach action, but also limited
contact action. As a seed treatment, rapidly translocated
systemically through the plant. Molluscicide which provokes
paralysis and death. Uses Control of all stages of major Lepidoptera and Coleoptera pests
and some Hemiptera and Diptera on cotton, soya beans, maize, vines,
fruit, vegetables, and many other crops, at 200-1000 g/ha; seed
treatment rates are 2500-10 000 g/tonne. Also used as a
molluscicide for control of slugs in cereals and oilseed rape.
Product analysis by hplc (CIPAC Handbook, 1998, H, 279; AOAC Methods, 17th Ed., 997.14). Residues determined by glc of a derivative (Pestic. Anal. Man., II, 201J; Pestic. Reg. Sec.,180.407) or by hplc. Details available from Bayer CropScience.
Reviews FAO/WHO 89, 91 (see part 2 of the Bibliography). Oral Acute oral LD50 for rats 66 (in water), 120 (in corn oil), dogs >800, monkeys
>467 mg/kg. Skin and eye Acute percutaneous LD50 for rabbits >2000 mg/kg; slightly irritating to their eyes and
skin. Inhalation LC50 (4 h) for rats 0.32 mg/l air. NOEL (2 y) for rats 3.75 mg/kg daily, for mice 5.0 mg/kg daily. ADI (JMPR) 0.03 mg/kg b.w. . Toxicity class WHO (a.i.) II; EPA (formulation) II EC classification T+; R25, R26| N; R50
Birds Acute oral LD50 for Japanese quail 2023 mg/kg. Dietary LC50 for mallard ducks 5620 mg/kg diet. Fish LC50 (96 h) for bluegill sunfish 1.4, rainbow trout >3.3 mg/l. Daphnia LC50 (48 h) 0.027 mg/l. Bees Moderately toxic to bees exposed to direct spray. No hazard to
honeybees after spray residues have dried.
EHC 64 (WHO, 1986; a review of carbamate insecticides in general). Animals In rats, rapidly degraded to methomyl, which was rapidly converted
to methomyl methylol, oxime, sulfoxide and sulfoxide oxime. These
unstable intermediates were converted to acetonitrile and CO2, which were eliminated primarily by respiration and in the urine;
a small fraction of acetonitrile was further degraded to acetamide,
acetic acid and CO2 (K. Huhtanen & H. W. Dorough, Pestic. Biochem. Physiol., 1976, 6, 571-583). Plants Major metabolites include thiodicarb methomyl, acetonitrile and CO2. Soil/Environment Rapidly degraded in soils of various types, under both aerobic and
anaerobic conditions, by hydrolysis and photolysis. The primary
degradation products are methomyl and methomyl oxime. DT50 of
thiodicarb in soil is 3-8 d, depending upon the soil type.