Propoxur

Description

Propoxur, 2-isopropoxyphenyl methylcarbamate (IUPAC),forms colorless crystals, which are moderately soluble in most organic solvents.

Description

Propoxur is a carbamate insecticide and an inhibitor of acetylcholinesterase. It is lethal to German cockroaches (B. germanica) with LD₅₀ values of 2.45, 4.73, and 1.06 μg per insect for newly emerged males, newly emerged females, and 4-week-old nymphs, respectively. Propoxur induces lactate dehydrogenase (LDH) release from and inhibits the growth of flounder gill cells (IC₅₀s = 86.59 and 89.96 μg/ml, respectively) via induction of necrosis. It also induces yolk sac and pericardial edema in zebrafish embryos when used at concentrations of 100 and 200 μg/ml. Propoxur (8.3 mg/kg) inhibits rat blood and brain cholinesterase, decreases ambulation and rearing in an open field test, and increases latency to escape foot shock after an audio stimulus in the two-way active avoidance box in rats.

Chemical properties

White, crystalline powder; odorless. Soluble in most alcohols; very slightly solublein water; unstable in highly alkaline media; stableunder normal conditions.

Chemical properties

Propoxur is a white to tan crystalline solid or powder. Faint characteristic odor

The Uses of Propoxur

Propoxur is an insecticide with contact and stomach action. It is mainly used in food storage areas. It also controls chewing and sucking pests on a wide range of crops.

The Uses of Propoxur

Propoxur is a non-systematic carbamate insecticide. Propoxur is used against a wide range of insects such as fleas, mosquitoes, ants, gypsy moths, and other agricultural pests. Propoxur functions by r eversibly inactivating the enzyme acetylcholinesterase in insects.

The Uses of Propoxur

Insecticide used for control of chewing and sucking insects in fruits, vegetables, ornamentals and forestry.

Definition

ChEBI: A carbamate ester that is phenyl methylcarbamate substituted at position 2 by a propan-2-yloxy group.

Preparation

Propoxur is prepared by reaction of 2-isopropoxyphenol with methylisocyanate.

General Description

White to tan crystalline powder with a faint, characteristic odor. Used as an insecticide.

Reactivity Profile

Propoxur is incompatible with the following: Strong oxidizers, alkalis [Note: Emits highly toxic methyl isocyanate fumes when heated to decomposition.] .

Hazard

Toxic by ingestion and inhalation. Cholinesterase inhibitor. Possible carcinogen.

Health Hazard

A highly toxic substance by ingestion, andpossibly by most other routes of exposure;moderately toxic by inhalation and skin contact; cholinesterase inhibitor; toxic effects aresimilar to those of other carbamate pesticidesand include excessive salivation, lacrimation, slow heart rate, blurred vision, twitchingof muscle and lack of coordination, nausea,weakness, diarrhea and abdominal pain; oralintake of probably 1.5–3 g could be fatal toadult humans; a teratogenic substance, producing adverse reproductive effects in experimental animals.
LD50 oral (rat): 70 mg/kg
LD50 skin (rat): 800 mg/kg
LC50 inhalation (rat): 1440 mg/m³/1 hr.

Agricultural Uses

Insecticide, Molluscicide: Not approved for use in EU countries. A non-systemic insecticide compatible with most fungicides and insecticides except those that are alkaline. It is often used in combination with azinphosmethyl, chlorpyrifos, cyfluthrin, dichlorvos, disulfoton or methocarb. It is used on sugar cane, cocoa, pome and stone fruit, grapes, maize, hops, rice, sugar beets, vegetables, cotton, and forestry and ornamentals to control pests such as chewing and sucking insects, ants, crickets, flies, mosquitoes, millepedes, jassids and cockroaches.

Trade name

(There are currently 695 registered active and/or canceled and/or transferred products in the U.S.) ARPROCARB®; BAY®; BAY® 5122; BAYER®; BAYER® B 5122; BAYGON®; BIFEX®; BLATTANEX®; BLATTOSEP®; BOLFO®; BO Q 5812-315®; BORUHO®; BORUHO® 50; BRIFUR®; BRYGOU®; CHEMAGRO® 9010; COMPOUND 39007; DALF DUST®; INVISI-GARD®; PILLARGON®; PRENTOX CARBAMATE®; PROPOGON®; PROPOTOX®; PROPOXYLOR®; PROPYON®; RHODEN®; SENDRAN®; SUNCIDE®; TENDEX®; TUGEN®; UNDEN®; UNDENE®

Potential Exposure

Personnel engaged in the manufacture, formulation and application of this organonitrogen agricul- tural chemical and pesticide.

Environmental Fate

Groundwater. According to the U.S. EPA (1986) propoxur has a high potential to leach to groundwater.
Photolytic. Though no products were identified, the half-life in UV irradiated water (λ >290 nm) was 87.9 hours (Jensen-Korte et al., 1987). When propoxur in ethanol was irradiated by UV light, only one unidentified cholinesterase inhibitor formed. Exposure to sunlight for 3 hours yielded no photodecomposition products (Crosby et al., 1965).
Chemical/Physical. Decomposes at elevated temperatures forming methyl isocyanate (Windholz et al., 1983) and nitrogen oxides (Lewis, 1990). Hydrolyzes in water to 1- naphthol and 2-isopropoxyphenol (Miles et al., 1988). At pH 6.9, half-lives of 78 and 124 days were reported under aerobic and anaerobic conditions, respectively (Kanazawa, 1987). Miles et al. (1988) studied the rate of hydrolysis of propoxur in phosphate-buffered water (0.01 M) at 26°C with and without a chlorinating agent (10 mg/L hypochlorite solution). The hydrolysis half-lives at pH 7 and 8 with and without chlorine were 3.5 and 10.3 days and 0.05 and 1.2 days, respectively (Miles et al., 1988). The reported hydrolysis half-lives of propoxur in water at pH 8, 9 and 10 were 16.0 days, 1.6 days and 4.2 hours, respectively (Aly and El-Dib, 1971). In a 0.50 N sodium hydroxide solution at 20°C, the hydrolysis half-life was reported to be 3.0 days (El-Dib and Aly, 1976).

Metabolic pathway

The principal pathways of propoxur metabolism in plants and animals are deisopropylation, hydrolysis of the carbamate ester to form a phenol and conjugation. Minor metabolites are formed by hydroxylation of the N-methyl group and the phenyl ring. Only insects form metabolites hydroxylated at the isopropoxy group.

Shipping

UN2757 Carbamate pesticides, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Degradation

Propoxur is hydrolysed by strong alkalis. DT₅₀ values at pH 7 and 9 (22°C) were 93 days and 30 hours (PM). Propoxur was hydrolysed in neutral aerated river water (half-life <2 days at 25 °C) (Kuhr and Dorough, 1976).
It is not rapidly photodegraded in aqueous solutions (PM) and is more stable than carbaryl (Crosby et al., 1965). Solutions of unlabelled propoxur in isopropanol, cyclohexane or cyclohexene were irradiated for 48 hours with a high-pressure Hg lamp with light of wavelength less than 280 nm filtered out. Analysis of samples was by HPLC. Photodecomposition was faster in isopropanol than in the hydrocarbon solvents. The main pathway of photodecomposition (see Scheme 1) was β-cleavage of the carbamate ester group to form isopropyl phenyl ether (2). 2-Isopropoxyphenol (3) was detected as a trace product (Schwack and Kopf, 1992).

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explo- sions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, alkalis, heat, and mois- ture. Emits highly toxic methyl isocyanate fumes when heated to decomposition.

Waste Disposal

In accordance with 40CFR165, follow recommendations for the disposal of pes- ticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contact- ing your regional EPA office. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations govern- ing storage, transportation, treatment, and waste disposal.