1-(2-Methylcyclohexyl)-3-phenylurea

232.32100

232.32

217-844-2

513S964LJO

131951

DTXSID7032474

White crystals|Colorless crystals

2924299034

41.13000

3.85070

1.08 g/cm³ @ Temp: 25 °C

133-138 °C

341.4ºC at 760 mmHg

121.5ºC

1.51

7.75e-05 M|Sol to the extent of 10% or more in ethanol, dimethylacetamide, dimethylformamide, and methylene chloride.|In dimethylacetamide 36.7, dimethylformamide 26, ethanol 16, isophorone 11.8, cellosolve 17.5, and methylene chloride 11.8 (all in g/100 mL) at 25 °C.|In water, 18 mg/L at 25 °C

0-6ºC

0.000257mmHg at 25°C

Odorless

Henry's Law constant = 6.8X10-11 atm-cu m/mol at 25 °C (est)

Noncorrosive

R36/37/38

26-61

Xi

It is stable up to its MP and in water at neutral pH, but is slowly decomp in acid and alkaline media

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.|Do not discharge effluent containing this product into lakes, streams, ponds, estuaries, oceans, or other waters unless in accordance with the requirements of a National Pollution Discharge Elimination System (NPDES) permit and the permitting authority has been notified in writing prior to discharge.|Burning: Small quantities of siduron should be burned and large quantities incinerated in a unit operting at 850 °C equipped with off gas scrubbing equipment. Recommendable method: Incineration. Not recommendable method: Hydrolysis. Peer review: Hydrolysis generates dimethylamine and aniline. (Peer- review conclusions of an IRPTC expert consultation (MAY 1985))

California Environmental Protection Agency/Department of Pesticide Regulation; Toxicology Data Review Summary for Siduron (1982-49-6).[Available from, as of May 13, 2009: http://www.cdpr.ca.gov/docs/risk/toxsums/toxsumlist.htm]|USEPA/Office of Prevention, Pesticides and Toxic Substances; Reregistration Eligibility Decision Document - Siduron EPA-HQ-OPP-2007-0973 (May 2008). The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of May 27, 2009: http://www.epa.gov/pesticides/reregistration/status.htm]|USEPA, Office of Prevention, Pesticides, and Toxic Substances; Revised HED Human Health Risk Assessment for Siduron (1982-46-2) (July 2008). EPA Docket No.: EPA-HQ-OPP-2007-0973-0019.

Not Classified

All mixers, loaders, applicators and other handlers must wear: Long-sleeve shirt and long pants, Chemical-resistant gloves, Shoes plus socks. In addition, for chemigation: All mixers and loaders must wear: NIOSH-approved dust/mist filtering respirator with MSHA/NIOSH approval number prefix TC-21C or a NIOSH-approved respirator with any N, R, P, or HE filter.

Nonflammable

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a POTW is acceptable only after review by the governing authority. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must meet Hazardous Material Criteria for disposal.

SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.|SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.|For several good reasons, .... herbicides ... should be handled and applied only with full attention to safety measures that minimize personal contact. Many formulations contain adjuvants (stabilizers, penetrants, surfactants) that may have significant irritating and toxic effects. A number of premixed formulations contain two or more active ingredients; the companion pesticides may be more toxic than the principal herbicide. Good hygienic practice should not be disregarded just because a pesticide is reported to have a high LD50 in laboratory rodents.|Avoid breating dust or spray mist. Avoid contact with skin, eyes, and clothing.|For more Preventive Measures (Complete) data for SIDURON (15 total), please visit the HSDB record page.

May irritate eyes, nose, throat, and skin.

LD50 Rat oral > 7500 mg/kg|LD50 Rabbit dermal >2000 mg/kg

/AQUATIC SPECIES/ Substituted ureas and carbamates are mechanistic inhibitors of the soluble epoxide hydrolase (sEH). ... A set of chemicals containing these functionalities /were screened/ in larval fathead minnow (Pimphales promelas) and embryo/larval golden medaka (Oryzias latipes) models to evaluate the utility of these systems for investigating sEH inhibition in vivo. ... Low lethality was observed in either larval or embryonic fish exposed to diuron [N-(3,4-dichlorophenyl), N'-dimethyl urea], desmethyl diuron [N-(3,4-dichlorophenyl), N'-methyl urea], or siduron [N-(1-methylcyclohexyl), N'-phenyl urea]. Dose-dependent inhibition of sEH was a sublethal effect of substituted urea exposure with the potency of siduron < desmethyl diuron = diuron, differing from the observed in vitro sEH inhibition potency of siduron > desmethyl diuron > diuron. Further, siduron exposure synergized the toxicity of trans-stilbene oxide in fathead minnows. Medaka embryos exposed to diuron, desmethyl diuron, or siduron displayed dose-dependent delays in hatch, and elevated concentrations of diuron and desmethyl diuron produced developmental toxicity...|/PLANTS/ Bermuda grass and certain bent grasses may be injured when applied pre-emergence.

Siduron's production may result in its release to the environment through various waste streams; its use as a herbicide(1) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), estimated Koc values from 330(SRC) determined from a log Kow of 3.80(3) and a structure estimation method(4) to 420(2), indicate that siduron is expected to have moderate mobility in soil(SRC). Volatilization of siduron from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.8X10-11 atm-cu m/mole(SRC) derived from its vapor pressure, 4.0X10-9(2), and water solubility, 18 mg/L(5). Siduron is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 4.0X10-9 mm Hg at 25 °C(2). Siduron is expected to undergo microbial degradation in soil with half-lives ranging from 90-150 days(3,6). Siduron is not expected to be decomposed by sunlight(3).|TERRESTRIAL FATE: No siduron metabolites were detected in barley after an 8-day adsorption period.|AQUATIC FATE: Based on a classification scheme(1), estimated Koc values from 330(SRC), determined from a log Kow of 3.80(3) and a structure estimation method(4), to 420(2) indicate that siduron may be expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(5) based upon an estimated Henry's Law constant of 6.8X10-11 atm-cu m/mole(6), derived from its vapor pressure, 4.0X10-9 mm Hg(2), and water solubility, 18 mg/L(7). According to a classification scheme(8), an estimated BCF of 150(SRC), from its log Kow and a regression-derived equation(9), suggests the potential for bioconcentration in aquatic organisms is high(SRC). Siduron is expected to undergo microbial degradation in water with a half-life ranging from 120-150 days(3). Hydrolysis may occur under acidic or alkaline conditions(10).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), siduron, which has a vapor pressure of 4.0X10-9 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase siduron may be removed from the air by wet or dry deposition(SRC). Siduron does not contain chromophores that absorb at wavelengths >290 nm(4) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Siduron is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(1). Siduron does not contain chromophores that absorb at wavelengths >290 nm(1) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC). In soil, siduron is not decomposed by sunlight(2). Substituted ureas may undergo hydrolysis under acidic as well as alkaline conditions(3).|After exposure in a thin film to full sunlight for 56 days, Siduron caused injury to germinating crabgrass identical with that caused by a nonirradiated check sample. Chemical analysis also verified that Siduron was not decomposed by sunlight.

An estimated BCF of 150 was calculated in fish for siduron(SRC), using a log Kow of 3.80(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC), provided the compound is not metabolized by the organism(SRC).

204.17 L/kg|The Koc of siduron is predicted in one study to be 420(1). Using a log Kow of 3.80(2) and a structure estimation method based on molecular connectivity indices(3), the Koc is estimated as 330(SRC). According to a classification scheme(4), these Koc values suggest that siduron is expected to have moderate mobility in soil. A Pesticide Leaching Potential (PLP) Index of 53 for foliar application and 57 for soil application was calculated for siduron using commonly reported Koc, persistence (half-life), and rate of application values(5,6). PLP values of 0 and 100 indicate no leaching potential and maximum leaching potential, respectively(6). Siduron was classified as having low mobility using retention factors from soil TLC using Hagerstown silty clay loam soil plates(7).|Adsorption increases as clay or organic matter content increases, and as cation exchange capacity of clay increases. The amount adsorbed on Keyport silt loam in equilibrium with 1 ppm in soil solution at 22.5 °C is 2.5 ppm (average Koc is 420 mL/g). Siduron is moderately resistant to leaching. Movement is least in soils high in clay or organic matter and greatest in sand.

The Henry's Law constant for siduron is estimated as 6.8X10-11 atm-cu m/mole(SRC) derived from its vapor pressure, 4.0X10-9 mm Hg(1), and water solubility, 18 mg/L(2). This Henry's Law constant indicates that siduron is expected to be essentially nonvolatile from water(3) and moist soil surfaces(SRC). Siduron is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure of 4.0X10-9 mm Hg(1).

GROUND WATER: From 1971 to 1991, 182 US wells were tested for siduron and showed no trace of the compound(1).

Occupational exposure to siduron may occur through inhalation and dermal contact with this compound at workplaces where siduron is produced or used. Use data indicate that the general population may be exposed to siduron via inhalation and dermal contact with consumer products containing siduron. (SRC)

Most readily absorbed through root system; less so through foliage and stems. ... Experimental evidence indicates that Siduron is translocated in the xylem.

Urine from a dog receiving 2500 ppm siduron in the diet was collected and analyzed for the parent compound and metabolites using a colorimetric method, and mass, IR, and NMR spectrometry, and a metabolic pathway was proposed; none of the parent compound was found, but three glucuronide conjugates of hydroxysubstituted siduron were isolated and identified, one substituted on the phenyl ring, one substituted on the cyclohexyl ring, and another substituted in both locations; it appears that siduron is first hydroxylated at either location, then both of these mono-hydroxylated compounds are hydroxylated again to form 1-(4-hydroxy-2-methylcyclo-hexyl)-3-p-hydroxyphenylurea; comparison of urine from the dog with that from a rat on a similar 2500 ppm diet, showed that the rat formed slightly less of the cyclohexyl-substituted compound than the dog; 800-1000 ppm of total siduron metabolites was bound in the urine of these two animals.|In studies with (14)C-labeled siduron, no metabolites ... were detectable in barley plants after an 8 day absorption period.|... Both phenyl and cyclohexyl rings are subjected to hydroxylation in the dog. ... The pathways proposed ... show that siduron is either hydroxylated at para position of phenyl nucleus or at 4 position of 2-methylcyclohexyl moiety. Both metabolites are further hydroxylated to form 1-(4-hydroxy-2-methylcyclohexyl)-3-(p-hydroxyphenyl)urea.|When urine samples of both dogs and rats were subjected to hydrolysis and analyzed for aminophenol /as well as/ aniline, it was observed that hydroxylation of the phenyl moiety was more prominent in the rat than in dog. Apparently rats exhibit particular efficiency in hydroxylating the aromatic nucleus of phenylureas. In another study in which (14)C- carbonyl-labeled compound was applied ... microbial degradation was major route of siduron disappearance in soil. Metabolites separated on thin-layer plates had same characteristics as those identified in urine, and /it was/ ... concluded that ring hydroxylation was also operative in soil environment.|For more Metabolism/Metabolites (Complete) data for SIDURON (6 total), please visit the HSDB record page.

Unlike other substituted urea herbicides, siduron is not a potent inhibitor of photosynthesis; phytotoxic symptoms appear to be associated with root growth inhibition.

Skin contamination should be treated promptly by washing with soap and water. Contamination of the eyes should be treated immediately by prolonged flushing of the eyes with large amounts of clean water. If dermal or ocular irritation persists, medical attention should be obtained without delay. /Other Herbicides/|Activated charcoal is probably effective in limiting irritant effects and reducing absorption of most or all of these herbicides. /Other herbicides/|If serious dehydration and electrolyte depletion have occurred as a result of vomiting and diarrhea, monitor blood electrolytes and and fluid balance and administer intravenous infusions of glucose, normal saline ringer's solution, or ringer's lactate to restore extracellular fluid volume and electrolytes. Follow this with oral nutrients as soon as fluids can be retained. Fluids serve to support excretion of the toxicants. Supportive measures are ordinarily sufficient for successful management of excessive exposures to these herbicides. /Other Herbicides/|/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/|For more Antidote and Emergency Treatment (Complete) data for SIDURON (6 total), please visit the HSDB record page.

/SURVEILLANCE/ The OPP Incident Data System (IDS) listed ... reported incidents involving siduron submitted to OPP since 1992. One individual reported weakness, headache, and dizziness two hours after applying a siduron product, and this person was treated in an emergency room.|/SURVEILLANCE/ The OPP Incident Data System (IDS) listed ... reported incidents involving siduron submitted to OPP since 1992 ... an individual inhaled the product and reported nausea, loss of hand coordination, difficulty breathing, and slurred speech.|/SURVEILLANCE/ ...The National Poison Control Centers (PCC) /reported/ between 1993 and 2003: one case in the Occupational Class involving moderate symptoms of abdominal pain and bronchospasm; nine cases in the Non-Occupational Class were reported, but only one presented mild symptoms; and twenty-five cases were suspected of exposure in the Children's Group, where nine were followed and presented no symptoms.|/SURVEILLANCE/ One incident was reported to the California Department of Pesticide Regulation since 1982, where a grower applied the product by sprinkler irrigation and reported a red and painful left eye and blurred vision.|/GENOTOXICITY/ INZ1318-70 (Lot No. A060588-31, 6-88; purity = 99.9%), dissolved in DMSO; human lymphocytes cultured from a male and female donor were treated with 0 (DMSO), 0.01, 0.06, 0.10, and 0.12 mg/mL for 3 hr, with and without activation (Aroclor 1254-induced rat liver S9 fraction); two replicate cultures/dose level were tested with appropriate vehicle and positive (MMC, CP) controls; two trials; 100 metaphases/treatment level were examined; no adverse effects; no significant increases in frequency of chromosomal aberrations were observed; positive controls were functional.

1-(2-methylcyclohexyl)-3-phenylurea

In 1992, siduron was used to treat sod crops at a rate of 4,000 lbs/acre/year in Connecticut, New York and New Hampshire, giving a total active ingredient application for each state of 156, 475 and 113 lbs, respectively

Granular formulations and wettable powder formulations only.|Also various dilute formulations including mixt with fertilizers for dry applications.|... 70% powder for manufacturing use. Various granulars.|Tupersan Weed Killer, wettable powder, 50% siduron|For more Formulations/Preparations (Complete) data for SIDURON (23 total), please visit the HSDB record page.

The WHO Recommended Classification of Pesticides by Hazard identifies Siduron as unlikely to present an acute hazard in normal use; Main Use: Herbicide.|It is recommended for treatment of grass at 2-8 kg AI/ha for new seedlings, 8-12 kg/ha for established turf.

Method: EPA-OGWDW/TSC 532; Procedure: high performance liquid chromatography with an ultraviolet/visible (UV/Vis) detector; Analyte: siduron; Matrix: drinking waters; Detection Limit: 0.067 ug/L.|Method: USGS-NWQL O-2060-01; Procedure: high performance liquid chromatography-mass spectrometry; Analyte: siduron; Matrix: water; Detection Limit: 0.0084 ug/L.|Method: EPA 632; Procedure: high performance liquid chromatography; Analyte: siduron; Matrix: municipal and industrial wastewater; Detection Limit: not provided.|RESIDUE: FENVRON METHOD MAY BE APPLICABLE IF NOT TOO LOW CONCN.|Product analysis is by HPLC. Residue analysis is by colorimetry.

Agrochemicals -> Herbicides