Cycluron

198.31

198.31

218-493-8

V8K90CTK5Q

DTXSID8041824

COLORLESS CRYSTALS

2924299034

32.3

2.76140

0.97g/cm3

138 °C

359.5ºC at 760mmHg

>100 °C

1.486

In water 1.2X10+3 mg/l at 20 deg C

1X10-7 MM HG @ 20 DEG C

Oral-Rat LD50: 1500 mg/kg

Combustion produces toxic nitrogen oxide gas

ODORLESS

The ureas form salts with strong acids. /Urea herbicides/

Noncorrosive

NONH for all modes of transport

3

22

26-36-45

YS7875000

Xn

The warehouse is ventilated, low temperature and dry; stored and transported separately from food materials

IT IS STABLE

P264, P270, P301+P312, P330, P501

H302

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.

|Warning|H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P301+P312, P330, and P501|Aggregated GHS information provided by 38 companies from 1 notifications to the ECHA C&L Inventory.

Avoid skin and eye contact and inhalation of spray mists. Prevent drifting.

moderately toxic

Cycluron's former production and use as a pre-emergence herbicide(1,2) will have resulted in its release to the environment(SRC).

TERRESTRIAL FATE: In soil ... demethylation of the nitrogen atom, hydrolytic cleavage, and liberation of carbon dioxide and ammonia /occurs/.|TERRESTRIAL FATE: Based on a recommended classification scheme(1), estimated Koc values ranging from 88 to 160(SRC), determined from an experimental water solubility of 1200 mg/l(2) and a structure estimation method(3), indicate that cycluron is expected to have moderate to high mobility in soil(SRC). Volatilization of cycluron from moist soil surfaces is not expected given an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole(SRC), using a fragment constant estimation method(4). Cycluron is not expected to volatilize from dry soil surfaces based on an estimated vapor pressure of 2.6X10-5 mm Hg(SRC), determined from a fragment constant method(5). Cycluron had a mobility factor of 3.8 in Hagerstown silty clay loam(4.3% organic matter, 30% clay, pH 5.5) and 4.3 in Lakeland sandy loam(3.3% organic matter, 10% clay, pH 6.2) soil columns(6). Mobility factors of 1 and 6 indicate no movement and maximum movement in the soil column, respectively(6). A 50% decrease in degradation of the urea herbicide, diuron, after soil sterilization(7) indicates that microorganisms may be important in the transformation of cycluron(SRC). The soil persistence of cycluron was reported as 4.5 to 60 weeks at doses of 0.125 to 2.0 lb/acre, based on the time taken for its activity to decrease below levels giving 50% and 20% growth inhibition in Italian ryegrass(8).|AQUATIC FATE: Based on a recommended classification scheme(1), estimated Koc values ranging from 88 to 160(SRC), determined from an experimental water solubility of 1200 mg/l(2) and a structure estimation method(3), indicate that little adsorption to suspended solids and sediment in water is expected for cycluron(SRC). Cycluron is not expected to volatilize from water surfaces based on an estimated Henry's Law constant of 1.2X10-8 atm-cu m/mole(SRC), developed using a fragment constant estimation method(5). According to a classification scheme(6), estimated BCF values ranging from 11 to 79(4,SRC), determined from an experimental water solubility of 1200 mg/l(2) and an estimated log Kow of 2.8(7,SRC), suggest that bioconcentration in aquatic organisms is low to moderate, not high(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), cycluron, which has a vapor pressure of 1X10-7 mm Hg at 20 °C(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase cycluron is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 15 hours(3,SRC). Particulate-phase cycluron may be physically removed from the air by wet and dry deposition(SRC).

The rate constant for the vapor-phase reaction of cycluron with photochemically-produced hydroxyl radicals has been estimated as 2.5X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 15 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC).

Bioconcentration factor = 12 (calculated from water solubility by regression equations). /From table/|An estimated BCF value of 79 was calculated for cycluron(SRC), using an estimated log Kow of 2.8(1,SRC) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms is moderate, not high(SRC). An estimated BCF value of 11 was calculated for cycluron(SRC), using an experimental water solubility of 1200 mg/l at 20 °C(4,SRC) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF value suggests that bioconcentration in aquatic organisms is low(SRC).

Koc = 93 (calculated from water solubility by regression equations). /From table/|Using a structure estimation method based on molecular connectivity indices(1), the Koc for cycluron can be estimated to be about 160(SRC). According to a recommended classification scheme(2), this estimated Koc value suggests that cycluron is expected to have moderate mobility in soil(SRC). An estimated Koc value of 88(3,SRC) was calculated from a measured water solubility of 1200 mg/l at 20 °C(4). According to a recommended classification scheme(2), this estimated Koc value suggests that cycluron is expected to have high mobility in soil(SRC).

The Henry's Law constant for cycluron is estimated as 1.2X10-8 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This value indicates that cycluron will be essentially nonvolatile from water surfaces(2,SRC). Cycluron's Henry's Law constant(1,SRC) indicates that volatilization from moist soil surfaces is not expected (SRC). Cycluron is not expected to volatilize from dry soil surfaces based on an estimated vapor pressure of 2.6X10-5 mm Hg(SRC), determined from a fragment constant method(3).

SURFACE WATER: Cycluron was identified in river water from the Main River in West Germany(1).

Occupational exposure to cycluron may have occurred through inhalation of dusts and dermal contact with this herbicide during its past application or at workplaces where cycluron was produced. (SRC)

Herbicidal ureas are mainly absorbed via the plant roots and are translocated with the transpiration current to their site of action in the green plant parts. /Ureas/

In ... plants, and warm-blooded animals, demethylation of the nitrogen atom, hydrolytic cleavage, and liberation of carbon dioxide and ammonia /occurs/.

Their herbicidal activity depends on inhibition of photosynthesis by blocking of electron transport in Photosystem II. /Ureas/|/In photosynthesis/ ... The urea herbicides interfere with the mechanism of oxygen evolution ... A flavin-containing enzyme may be involved in the photosynthetic reaction sequence in which oxygen is produced. Blocking this enzyme by urea results in the destruction of the plant by starvation or as a result of accumulation of a phytotoxic product. /Urea herbicides/

cycluron

ALIPUR, AN EMULSIFIABLE CONCENTRATE (150 G CYCLURON AND 100 G CHLORBUFAM/L).|... /TRIXABON IS/ COMBINATION OF DIMEXAN, CYCLURON (OMU), AND CHLORBUFAM (BIPC) AS AN EMULSIFIABLE CONCENTRATE, 73.2% WEIGHT/VOLUME ACTIVE INGREDIENTS. /TRIXABON/|HS 61|ALIPUR-O

CYCLURON WAS INTRODUCED IN 1958 BY BASF AG AS COMPONENT OF THEIR HERBICIDE 'ALIPUR', PROTECTED BY DBP (WEST GERMAN PATENT) 1027930; 1062482.|Product discontinued by BASF Aktiengesellschaft.|NITROSATION OF CYCLURON WAS INVESTIGATED IN PRESENCE OF 6 N HCL OR ACETIC ACID @ PH 1 & EXCESS SODIUM NITRITE FOR 4 HR @ 37 °C AND FOUND TO FORM A 7% YIELD OF DIMETHYLNITROSAMINE.|Discontinued name: Alipur (with chlorbufam) (BASF AG)

Product analysis: Potentiometric titration with perchloric acid in acetic anhydride, or thin-layer chromatography on silica gel G (Merck) ... as described by J Askew et al, J Chromatogr 37: 369-72 (1968).|... Residues by GLC for determination of the dimethylamine released on hydrolysis.|... Hydrolysis by reflux with alkali generates the parent amine. This reaction is used as a basis for colorimetric analysis. /Urea herbicides/|Elemental analysis: calculated 14.13% N. Residue analysis: Extraction with acetone and benzene, clean-up by chromatography, followed by boiling with phosphoric acid (d 1.17), distillation of the dimethylamine from alkaline solution, reaction with 2,4- dinitrofluorobenzene, and determination of the resulting 2,4- dinitro-N,N-dimethylaniline by GC with ECD (Methodensammlung Rueckstandsanalytik, 86).

Agrochemicals -> Herbicides|Pharmaceuticals