Thiophanate

370.45

370.45

245-741-2

5Q0Y96D5I8

170810

2588

DTXSID3034531

Colorless plates from acetone|Yellow or yellowish crystalline solid

29309090

164.90000

3.50020

1.414g/cm3

194 °C (decomp)

1.676

Almost insoluble in water; sparingly soluble in most organic solvents

0-6°C

LD50 orally in mice and rats: >15 g/kg (Eichler)

Odorless

Forms unstable solutions of salts with aqueous alkali and forms complexes with divalent transition metal ions, for example copper.

Hydrolyzed by alkaline media.

Amides and Imides

THIOPHANATE ETHYL is a carbamate ester. Carbamates are chemically similar to, but more reactive than amides. Like amides they form polymers such as polyurethane resins. Carbamates are incompatible with strong acids and bases, and especially incompatible with strong reducing agents such as hydrides. Flammable gaseous hydrogen is produced by the combination of active metals or nitrides with carbamates. Strongly oxidizing acids, peroxides, and hydroperoxides are incompatible with carbamates. This substance is incompatible with copper containing compounds.

2588

3

S24/25

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Thiophanate-ethyl applied to soil at an unspecified concn was taken up in peppers and eggplants and persisted up to 4 weeks in the leaves(1).

LD50 Rat ip 2400 mg/kg|LD50 Mouse ip 3750 mg/kg

Thiophanate-ethyl's former(2) production and use as an fungicide(1) resulted in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 49(SRC), determined from a structure estimation method(2), indicates that thiophanate-ethyl is expected to have very high mobility in soil(SRC). Volatilization of thiophanate-ethyl from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 5.18X10-13 atm-cu m/mole(SRC), using a fragment constant estimation method(3). Thiophanate-ethyl is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.21X10-9 mm Hg(SRC), determined from a fragment constant method(4). In the field, thiophanate-ethyl has been shown to break down to benzimidazole ethyl carbamate(5), although the degradation process was not identified. Based on test results using analogous thiophanate-methyl which degrades rapidly in soils of various textures to methyl-2-benzimidazolecarbamate(6), biodegradation of thiophanate-ethyl may be an important environmental fate process in soil(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 49(SRC), determined from a structure estimation method(2), indicates that thiophanate-ethyl is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 5.2X10-13 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). Thiophenate-ethyl degrades in aqueous solution (25 °C; 48 hr) by 30% to ethyl benzimidazole-2-yl carbamate (MBC)(8). According to a classification scheme(5), an estimated BCF of 8(SRC), from an estimated log Kow of 2.1(6) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), thiophanate-ethyl, which has an estimated vapor pressure of 1.2X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase thiophanate-ethyl may be removed from the air by wet and dry deposition(SRC).

Thiophanate-ethyl will hydrolyze although this is not an important environmental fate process(SRC). A base-catalyzed second-order hydrolysis rate constant of 9.86X10-6 L/mole-sec(SRC) was estimated using a structure estimation method(1); this corresponds to half-lives of 2.228X10+4 and 2.228X10+3 years at pH values of 7 and 8, respectively(1). Thiophanate-ethyl is expected to be a stable compound by analogy to thiophanate-methyl which is stable in neutral, aqueous solution at room temperature and is stable to air and sunlight(2). Thiophanates have an absorption maximum of 263 nm (range was 220-310 nm); thiophanate-ethyl degrades in aqueous solution (25 °C; 48 hr) by 30% to ethyl benzimidazole-2-yl carbamate (MBC)(3). MBC is more toxic than the thiophanates. Degradation was not observed in dark controls. An aqueous solution of thiophanate-ethyl applied to plant foliage exposed to sunlight was found to degrade at a similar rate under the same environmental conditions(3).

An estimated BCF of 8 was calculated for thiophanate-ethyl(SRC), using an estimated log Kow of 2.1(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

Using a structure estimation method based on molecular connectivity indices(1), the Koc for thiophanate-ethyl can be estimated to be 49(SRC). According to a classification scheme(2), this estimated Koc value suggests that thiophanate-ethyl is expected to have very high mobility in soil.

The Henry's Law constant for thiophanate-ethyl is estimated as 5.2X10-13 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that thiophanate-ethyl is expected to be essentially nonvolatile from water surfaces(2). Thiophanate-ethyl's Henry's Law constant(1) indicates that volatilization from moist soil surfaces will not occur(SRC). Thiophanate-ethyl is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.2X10-9 mm Hg(SRC), determined from a fragment constant method(3).

GROUNDWATER: Thiophanate was detected in 0 of 12 groundwater samples collected in Oregon from 1985-1987(1).

Occupational exposure to thiophanate-ethyl may have occured through dermal contact with this compound at workplaces where thiophanate-ethyl was produced or used. (SRC)

Agents that kill parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal. (See all compounds classified as Anthelmintics.)|Chemicals that kill or inhibit the growth of fungi in agricultural applications, on wood, plastics, or other materials, in swimming pools, etc. (See all compounds classified as Fungicides, Industrial.)|Substances used in the treatment or control of nematode infestations. They are used also in veterinary practice. (See all compounds classified as Antinematodal Agents.)

After oral administration of 40 mg/kg of thiophanate to dairy cows, the active metabolite, ethyl-1H-benzimidazol-2-yl carbamate (EBC) reached a maximal concentration of 0.44 ug/ml during the first milking and was eliminated by the mammary gland after 60 h. BCE is teratogenic in rats at doses of over 6.8 mg/kg while thiophanate at doses of up to 148 mg/kg is not. These results indicate that thiophanate treatment for dairy cattle may be questionable.

Bis-Thioallophanate, Dimethylphenylene

USEPA/OPP Pesticide Code 103401; Trade Names: Topsin, Cercobin, Cleary's 3336.|Wettable powder (500 g a.i./kg)

EPA Method PMD-THN. Determination of Thiophanate by UV Spectroscopy.

Agrochemicals -> Fungicides

Thiophanate has known environmental transformation products that include carbendazim.