Methazole

261.06200

261.06

243-761-6

E35M7EMD3V

2588

DTXSID1040293

White solid

2934999027

57.14000

1.43600

Methazole appears as colorless crystals to light tan solid. Non corrosive. Herbicide.

1.24 g/cm³ @ Temp: 25 °C

123-124 °C

348.7ºC at 760 mmHg

164.7ºC

1.618

1.5mg/L(25 ºC)

0-6ºC

133 uPa at 25 deg C

LD50 in adult male, female rats (mg/kg): 777, 925 orally (Gaines, Linder)

Henry's Law constant= 2.29X10-7 atm-cu m/mole

LIGHT TAN SOLID /TECHNICAL PRODUCT/|Exothermic decomp begins at 273 °C.

Hydrolyzed by strong acids and bases.

Amides and Imides

MEETHAZOLE is an oxadiazole.

Non-corrosive to metals

2588

R21/22;R36/38;R51/53

S61;S36/S37

Xn,N

Stable in neutral or acid solution but hydrolyzes in base to form several products.

P264, P270, P273, P280, P301+P312, P302+P352, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P391, P501

H302

WHITACRE DM ET AL; METHAZOLE; ANAL METHODS PESTIC PLANT GROWTH REGUL 10: 367-84 (1978). A REVIEW WITH 9 REF DISCUSSING BIOLOGICAL, CHEMICAL, & PHYSICAL PROPERTIES & METHODS OF ANALYSIS FOR METHAZOLE.|KIMBROUGH RD; INTERNATIONAL SYMPOSIUM ON HAZARDS OF PESTICIDES TO THE ENVIRONMENT AND HUMAN HEALTH, ALEXANDRIA, EGYPT, NOV 1-3 (1978); J ENVIRON SCI HEALTH PESTIC FOOD CONTAM AGRIC WASTES 15 (6): 977 (1980). HUMAN HEALTH EFFECTS OF SELECTED PESTICIDES CHLORO ANILINE DERIVATIVES.

|Warning|H302: Harmful if swallowed [Warning Acute toxicity, oral]|P264, P270, P273, P280, P301+P312, P302+P352, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P362, P363, P391, and P501

Wear protective clothing, including gloves, as methazole can cause chloracne.

Avoid skin and eye contact. Keep away from food and feedstuffs.|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.

... Mildly irritating to the skin and eyes. ...

LD50 RABBIT PERCUTANEOUS GREATER THAN 12500 MG/KG|LD50 Rat inhalation >200 mg/l/4 hr

Chlormethazole's use as a herbicide(1-2) releases the compound directly to the environment through applications in powders, sprays and other routes of application(SRC).

TERRESTRIAL FATE: METHAZOLE WAS DEGRADED TO 3-(3,4-DICHLOROPHENYL)-1-METHYLUREA & 3-(3,4-DICHLOROPHENYL) UREA OVER A 6-WK PERIOD FOLLOWING APPLICATION TO ELMWOOD SANDY LOAM SOIL COLUMNS. AFTER APPLICATION TO ELMWOOD SANDY LOAM SOIL COLUMNS, METHAZOLE LEVEL DECR TO 27% OF ORIGINAL AMT, OF TOTAL RADIOACTIVITY REMAINING IN THE SOIL COLUMNS AFTER 44 DAYS, APPROX 80% REMAINED ABOVE 6.35 MM.|TERRESTRIAL FATE: MOVEMENT OF METHAZOLE TAGGED WITH (14)C WAS STUDIED IN LAKELAND SAND, NACOGDOCHES SANDY LOAM, NORWOOD CLAY LOAM, & MILLER CLAY SOILS, VERY LITTLE (14)C WAS DETECTED IN LEACHATE. METHAZOLE WAS READILY CONVERTED TO 1-(3,4-DICHLOROPHENYL)-3-METHYLUREA (DCPMU) & 1-(3,4-DICHLOROPHENYL)UREA (DCPU) IN THE SOILS STUDIED, WITH 1-(3,4-DICHLOROPHENYL)-3-METHYLUREA BEING PRESENT IN LARGEST QUANTITIES.|Terrestrial Fate: Stabilized on attapulgite or montmorillonite clays.|TERRESTRIAL FATE: The results of degradation studies in four different soil types found that 14-C labelled chlormethazole degraded readily to 1-(3,4-dichlorophenyl)-3-methyl urea (DCPMU)(1); the degradation mechanism was not examined, but the degradation product is known to be a major degradation product resulting from aqueous hydrolysis or photodecomposition(2). Soil microorganisms can reportedly degrade chlormethazole to its major metabolites (including DCPMU)(3), but the relative importance of biodegradation in soil is unknown(SRC). The US Dept of Agric's Pesticide Properties Database lists a soil half-life of 14 days for chlormethazole(4). Chlormethazole applied to soil at agricultural rates degrades quickly and generally disappears within 30 to 60 days(3). Soil column leaching tests(1) and a measured Koc value of 2620(5) indicated that chlormethazole will leach very little in most soils(SRC). Chlormethazole will reportedly volatilize from inert surfaces, but much less so from foliar surfaces(3).|For more Environmental Fate (Complete) data for CHLORMETHAZOLE (6 total), please visit the HSDB record page.

The rate constant for the vapor phase reaction of chlormethazole with photochemically produced hydroxyl radicals has been estimated to be 2.47X10-11 cu cm/molecule-sec at 25 °C which corresponds to an atmospheric half-life of about 15.7 hours at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(1,SRC). Results of sunlight exposure studies indicate that chlormethazole is susceptible to photodecomposition(2); when thin films of 14-C labelled chlormethazole on glass plates were exposed to sunlight for 8 hr, nearly 60% of initial chlormethazole degraded while virtually no degradation occurred on dark controls(2); the decomposition products included 6,7-dichloro-1-methyl-2-benzimidazolinone, 5,6-dichloro-1-methyl-2-benzimidazolinone, and 1-methyl-3-(3,4-dichlorophenyl)urea(2); when aqueous solutions of 14-C labelled chlormethazole were exposed to sunlight for 7 days, approximately 65% of initial chlormethazole decomposed while only 20% degraded in dark controls(2); the same degradation products were identified(2); the major formation of the urea product in dark controls suggests a possible hydrolysis route of formation(2,SRC).

Based upon a water solubility of 1.5 mg/L at 25 °C(1), the BCF of chlormethazole can be estimated to be 490 from a regression derived equations(2,SRC). This BCF value suggests that bioconcentration in aquatic organisms may have some importance(SRC); however, it is reported that chlormethazole residues tend to dissipate quickly and do not bioaccumulate(3).

3.02e+03 L/kg|The US Dept Agric's Pesticide Properties Database lists a Koc value of 3000 for chlormethazole(1). An experimental Koc value of 2620 has also been reported(2). According to a suggested classification scheme(3), these Koc values suggest that chlormethazole has low to slight mobility in soil(SRC). In soil column leaching tests using sand, sandy loam, clay loam and clay soils, very little chlormethazole leached below a 15 cm depth(4).

Based upon a vapor pressure of 1X10-6 mm Hg(1) and a water solubility of 1.5 mg/L at 25 °C(1), the Henry's Law constant for chlormethazole can be estimated to be 2.29X10-7 atm-cu m/mole (SRC). This value of Henry's Law constant indicates that chlormethazole is essentially nonvolatile from water(2). Chlormethazole will reportedly volatilize from inert surfaces, but much less so from foliar surfaces(3).

Occupational exposure to chlormethazole occurs through dermal contact and inhalation of sprays, especially to workers applying the compound as a herbicide(1).

LITTLE OR NO INTACT HERBICIDE WAS TRANSLOCATED FROM ROOTS TO LEAVES BUT RADIOACTIVITY IN LEAVES ACCOUNTED FOR 80-90% OF METHANOL-SOLUBLE LABEL @ 47 DAYS POSTTREATMENT. MOST OF THIS (14)C WAS RECOVERED AS DCPU /1-(3,4-DICHLOROPHENYL)UREA/ (50-60%) & UNIDENTIFIED POLAR METABOLITE (30-40%).|Absorbed via roots and leaves. Translocated in the sap stream.

BIOXONE WAS READILY METABOLIZED BY COTTON (GOSSYPIUM HIRSUTUM L) TO 1-(3,4-DICHLOROPHENYL)-3-METHYLUREA (DCPMU) & 1-(3,4-DICHLOROPHENYL)UREA (DCPU). 3 DAYS AFTER TREATMENT OF EXCISED LEAVES /OF COTTON/, 1-(3,4-DICHLOROPHENYL)UREA ACCOUNTED FOR 55-70% OF APPLIED (14)C. INTACT ROOTS METABOLIZED BIOXONE RAPIDLY TO 1-(3,4-DICHLOROPHENYL)-3-METHYLUREA & 1-(3,4-DICHLOROPHENYL)UREA ... SOME CONJUGATION OF PLANT PROTEINS WITH 1-(3,4-DICHLOROPHENYL)-3-METHYLUREA & 1-(3,4-DICHLOROPHENYL)UREA WAS INDICATED ... .|MOUSE LIVER MICROSOMAL OXIDASE METAB GIVES PRIMARILY DESMETHYLMETHAZOLE UNDER AEROBIC CONDITIONS & ARNHC(O)NHCH3 UNDER NITROGEN. 3-HYDROXY-1-METHYLUREA FROM SPINACH IS REDUCED TO 1-METHYLUREA, REMAINDER IS CONJUGATED AS N-O-BETA-D-GLUCOSIDE & ITS 6-O-MALONYL ESTER.

1. SKIN CONTAMINATION SHOULD BE REMOVED PROMPTLY BY WASHING WITH SOAP AND WATER. CONTAMINATION OF THE EYES SHOULD BE TREATED IMMEDIATELY BY PROLONGED FLUSHING OF THE EYES WITH COPIOUS AMOUNTS OF CLEAN WATER. IF DERMAL OR OCULAR IRRITATION PERSISTS, MEDICAL ATTENTION SHOULD BE OBTAINED WITHOUT DELAY. /OTHER HERBICIDES/|2. INGESTIONS OF THESE HERBICIDES ARE LIKELY TO BE FOLLOWED BY VOMITING AND DIARRHEA DUE TO THE IRRITANT PROPERTIES OF MOST OF THE TOXICANTS. ... A. IF LARGE AMOUNTS OF HERBICIDE HAVE BEEN INGESTED, AND IF THE PATIENT IS FULLY ALERT INDUCE EMESIS WITH SYRUP OF IPECAC, FOLLOWED BY SEVERAL GLASSES OF WATER. DOSAGE FOR ADULTS AND CHILDREN OVER 12 YEARS: 30 ML; DOSAGE FOR CHILDREN UNDER 12 YEARS 15 ML. WHEN VOMITING HAS STOPPED, GIVE ACTIVATED CHARCOAL. ADD SORBITOL TO THE CHARCOAL SLURRY UNLESS DIARRHEA HAS ALREADY COMMENCED. IF, FOR SOME REASON, THE PATIENT IS NOT FULLY ALERT, PUT IN PLACE A CUFFED ENDOTRACHEAL TUBE TO PROTECT THE AIRWAY, THEN ASPIRATE AND LAVAGE THE STOMACH WITH A SLURRY OF ACTIVATED CHARCOAL. LEAVE A QUANTITY OF CHARCOAL, WITH SORBITOL, IN THE STOMACH BEFORE WITHDRAWING THE STOMACH TUBE. REPEATED ADMINISTRATION OF CHARCOAL AT HALF OR MORE THE INITIAL DOSAGE EVERY 2-4 HOURS MAY BE BENEFICIAL. /OTHER HERBICIDES/|2. B. IF THE AMOUNT OF INGESTED HERBICIDES WAS SMALL, IF EFFECTIVE EMESIS HAS ALREADY OCCURRED, OR IF TREATMENT IS DELAYED, ADMINISTER THE ACTIVATED CHARCOAL AND SORBITOL BY MOUTH. C. 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. D. SUPPORTIVE MEASURES ARE ORDINARILY SUFFICIENT FOR SUCCESSFUL MANAGEMENT OF EXCESSIVE EXPOSURES TO THESE HERBICIDES. /OTHER HERBICIDES/

2-(3,4-dichlorophenyl)- 4-methyl-1,2,4-oxadiazolidine-3,5-dione

TECHNICAL GRADE /IS/ 95% PURE; WETTABLE POWDER (750 G AI/KG); GRANULES (50 G/KG).|Mixed formulations: (methazole +) chlorthal-dimethyl; simazine. Wettable powder;granules|Probe: Herbicide is available as 75% wettable powder and as 5% granules.

METHAZOLE APPEARS TO BE A PROHERBICIDE WHILE DIURON & LINURON ACT DIRECTLY & VIA METABOLITES AS PHOTOSYNTHETIC INHIBITORS.|It is a selective herbicide effective against certain grasses and many broad-leaved weeds: pre-emergence in garlic and potatoes (1-2 kg ai/ha); as a directed spray on soil or emerged weeds in citrus, stone-fruits, nuts, tea and established vines (6 kg/ha) and on cotton 15 cm tall (1-2 kg/ha), onions (>2 leaves) (2.5 kg/ha), newly seeded or winter-dormant lucerne (>1 yr old) (2.25 kg/ha). It is preferably applied to moist soil; lower rates are applicable to light sandy soils.

INFRARED SPECTROPHOTOMETRIC METHOD FOR METHAZOLE FORMULATION, INCLUDING CHLORMETHAZOLE.|Product analysis is by IR spectrometry. Residues may be determined by GLC with ECD or by HPLC.

Agrochemicals -> Herbicides