Дисульфид тетраметилтиурама

Description

Tetramethylthiuram disulfide, known as thiram and TMTD, is a dithiocarbamate fungicide. The molecule consists of two dimethylthiocarbamoyl fragments linked by a disulfide bridge. The action is contact and protective, with multiple points of application: the substance suppresses spore germination and mycelial growth, interfering with several enzyme systems of the fungus at once. The multisite mechanism slows down the selection of resistant populations—for this reason, thiram is retained in protection schemes as a partner for systemic drugs with a single target. The second purpose is an accelerator for the vulcanization of rubber, the third is a repellent against rodents and ungulates.

Basic Attributes

• CAS No.: 137-26-8
• Chemical formula: C6H12N2S4
• Molecular weight: 240.43
• Exact weight: 240.43
• EU number: 205-286-2
• BRN: 1725821
• RTECS number: JO1400000
• HS code: 29303000
• PSA Specifications: 121
• XLogP3: 1.7
• Appearance: white crystalline substance, supplied in commercial forms, including in the form of flowable suspension concentrates
• Smell: characteristic
• Density: 1.29 g/cm³ at 20 °C
• Melting point: 155–156 °C
• Boiling point: 129 °C at 20 Torr pressure
• Flash point: 89 °C
• Refractive index: 1.677
• Solubility in water: 16.5 mg/l at 20 °C
• Steam pressure: 0.000008 mm Hg. Art.
• Storage conditions: 0–6 °C

Mechanism of action and spectrum

The drug works on the surface of the seed or leaf, creating a protective barrier, and does not penetrate the plant systemically. The germinating spore comes into contact with the active substance and dies before it penetrates the tissue, so the treatment is preventive in nature and should be ahead of infection.

• Target diseases: seed rot, seedling rot, root rot and damping off of seedlings, grain smut, smut and hard smut diseases
• Target crops: grains (barley, millet, oats, rye, triticale), beans and peas, cabbage, beets, eggplant, flax, onions, soybeans, sunflower, tomato, fruits - apple, pear, cherry, strawberry
• Additionally: repelling rabbits and deer from fruit trees and ornamental plantings
• Forms of release: wettable powders, flowing suspension concentrates, granular preparations - for seed treatment, spraying during the growing season and application to the soil

Non-pesticide applications

• primary and secondary vulcanization accelerator in the production of natural, butyl rubber, butadiene, styrene butadiene, synthetic isoprene and nitrile butadiene rubbers
• wood preservative, disinfectant in mushroom growing
• lubricating oil additive

Stability and behavior in the environment

• Decomposes in an acidic environment; prolonged exposure to heat, air or moisture deteriorates the quality of the drug
• Estimated half-life of DT50 at 22°C: 128 days at pH 4, 18 days at pH 7, 9 hours at pH 9
• Half-life in soil under dark aerobic conditions: about 8.9 days - the substance is not firmly fixed in the soil
• The main danger is related to the environment: when it gets into the ground, the substance migrates and pollutes groundwater and watercourses. In the event of a spill, measures to limit the spread are taken immediately
• Thermal decomposition is accompanied by the release of toxic gases containing nitrogen oxides and sulfur oxides
• Regulatory status: inclusion in the list of active substances under EU regulation 1107/2009 has expired, while the drugs are approved for use in a number of EU member states (Austria, Germany, Spain, the Netherlands, Poland, Portugal, Romania)

Toxicity

• LD50 oral, rat: 560 mg/kg
• LD50 oral, mouse: 1250 mg/kg

Safety Information

• Hazard category: 9; packaging level: III
• Transport codes: UN 2771 / UN 2811
• WGK Germany: 3
• Hazard class code: 20/22-36/38-43-48/22-50/53
• Safety instructions: 26-36/37-60-61
• Tags: Xn, N
• Hazard Statements: H302
• Precautions: P201, P202, P260, P261, P264, P270, P271, P272, P273, P280, P281, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P308+P313, P312, P314, P321, P330, P332+P313, P333+P313, P337+P313, P362, P363, P391, P405, P501

Storage and handling

The warehouse is ventilated, dry, at low temperature; recommended mode 0–6 °C. Storage and transportation separately from food and feed. The hazard class code reflects the irritant effect on the skin and eyes (36/38), the ability to cause sensitization upon contact with skin (43) and the danger of damage to organs during prolonged exposure (48/22), therefore work is carried out with gloves, safety glasses and protective clothing, and in case of dust - with a respirator. Instructions 60 and 61 require that the substance and its waste not enter the environment and be disposed of as hazardous.