1-naphthyl methylcarbamate

1-naphthalenyl methylcarbamate

C₁₂H₁₁NO₂

Colourless to light tan crystals. 

142 ºC 

4.1 ´ 10-2 mPa (23.5 ºC) 

193℃

 1.232 (20 ºC) 

In water 120 mg/l (20 ºC). Readily soluble in polar organic solvents. In dimethylformamide, dimethyl sulfoxide 400-450, acetone 200-300, cyclohexanone 200-250, isopropanol 100, xylene 100 (all in g/kg, 25 ºC). 

Stable under neutral and weakly acidic conditions. Hydrolysed in alkaline media to 1-naphthol; DT50 c. 12 d (pH 7), 3.2 h (pH 9). Stable to light and heat.  F.p. 193 °C 

7.39 ´ 10-5 Pa m3 mol-1 (calc.) 

1.85

Weak cholinesterase inhibitor. 

Insecticide with contact and stomach action, and slight systemic properties. 

Control of Lepidoptera, Coleoptera, and other chewing and sucking insects, at 0.25-2.0 kg/ha, on more than 120 different crops, including vegetables, tree fruit (including citrus), mangoes, bananas, strawberries, nuts, vines, olives, okra, cucurbits, peanuts, soya beans, cotton, rice, tobacco, cereals, beet, maize, sorghum, alfalfa, potatoes, ornamentals, forestry, etc. Control of earthworms in turf. Used as a growth regulator for fruit thinning of apples. Also used as an animal ectoparasiticide.

Non-phytotoxic if used as directed. Under certain conditions, some varieties of apple and pear may be injured. 

 Incompatible with alkaline materials such as Bordeaux mixture, lime, and lime sulfur. 

ReviewsFAO/WHO 92, 94 (see part 2 of the Bibliography).

Acute oral LD50 for rats 264, female rats 500, rabbits 710 mg/kg.

Acute percutaneous LD50 for rats >4000, rabbits >2000 mg/kg. Slight eye irritant, mild skin irritant (rabbits). 

LC50 (4 h) for rats 3.28 mg/l air. 

(2 y) for rats 200 mg/kg diet. 

(JMPR) 0.008 mg/kg b.w. [2001]. 

WHO (a.i.) II; EPA (formulation) I ('Tercyl' 85WP), II ('Sevin' 80S), III 

R40| Xn; R22| N; R50 

Acute oral LD50 for young mallard ducks >2179, young pheasants >2000, Japanese quail 2230, pigeons 1000-3000 mg/kg. 

LC50 (96 h) for rainbow trout 1.3, sheepshead minnow 2.2, bluegill sunfish 10 mg/l. 

LC50 (48 h) 0.006 mg/l. 

EC50 (5 d) for Selenastrum capricornutum 1.1 mg/l. 

LC50 (28 d ) 106-176 mg/kg soil. 

Metabolites are 4-hydroxycarbaryl, 5-hydroxycarbaryl and methylol-carbaryl. 

In mammals, carbaryl does not accumulate in body tissues, but is rapidly metabolised to non-toxic substances, particularly 1-naphthol. This, together with the glucuronic acid conjugate, is eliminated predominantly in the urine and faeces. Metabolism of carbamate insecticides is reviewed (M. Cool & C. K. Jankowski in "Insecticides"). 

Under aerobic conditions, carbaryl at 1 ppm degraded with DT50 7-14 d in a sandy loam and 14-28 d in a clay loam.