NOMENCLATURE    

Common name thiophanate-methyl 

IUPAC name dimethyl 4,4′-(o-phenylene)bis(3-thioallophanate)    

Chemical Abstracts name dimethyl [1,2-phenylenebis(iminocarbonothioyl)]bis[carbamate] 

CAS RN [23564–05–8]    

PHYSICAL CHEMISTRY    

Mol. wt. 342.4 M.f. C₁₂H₁₄N₄O₄S₂ Form Colourless crystals. M.p. 172 °C (decomp.) V.p. 0.0095 mPa (25 °C) Kow logP = 1.50 Solubility In water 0.0224 (pH 4), 0.0221 (pH 5), 0.0207 (pH 6), 0.0185 (pH 7), 0.0168 (pH 7.5) (all in g/l, 20 °C) In acetone 58.1, cyclohexanone 43, methanol 29.2, chloroform 26.2, acetonitrile 24.4, ethyl acetate 11.9 (all in g/kg, 23 °C). Slightly soluble in hexane. Stability Stable in neutral, aqueous solution at room temperature. Stable to air and sunlight. Quite stable in acidic solution at room temperature; unstable in alkaline solution; DT₅₀ 24.5 h (pH 9, 22 °C). Formulated product is stable ≥2 y below 50 °C. pKa 7.28     

APPLICATIONS    

Biochemistry Carbendazim (q.v.) precursor. 

Mode of action Systemic fungicide with protective and curative action. Absorbed by the leaves and roots.    

Uses A fungicide used effective against a wide range of fungal pathogens, including: eyespot and other diseases of cereals; scab on apples and pears; Monilia disease and bitter rot on apples; Monilia spp. on stone fruit; canker on fruit trees; powdery mildews on pome fruit, stone fruit, vegetables, cucurbits, strawberries, vines, roses, etc.; Botrytis and Sclerotinia spp. on various crops; leaf spot diseases on beet, oilseed rape, celery, celeriac, etc.; club root on brassicas; dollar spot, Corticium, and Fusarium spp. on turf; grey mould in vines; blast in rice; Sigatoka disease in bananas; and many diseases in floriculture. Also used on almonds, pecans, tea, coffee, peanuts, soya beans, tobacco, chestnuts, sugar cane, citrus fruit, figs, hops, mulberries, and many other crops. Used additionally as a wound protectant for pruning cuts on trees.    

Formulation types DP; PA; SC; WP. 

Compatibility Incompatible with alkaline and copper-containing compounds.