Sevin insecticide

Sevin. 1-Naphthalenol methylcarbanate [63-25-2] (Sevin) (44) was developed as an insecticide. However, the conception of the molecule, in the mid-1950s, was as a possible herbicide. The compound ultimately was useless as a herbicide, but in routine testing it was discovered to be an excellent insecticide. Sevin was active in the oat mesocotyl assay and demonstrated weak auxin-like activity. During the development of Sevin, it caused massive apple drop in the western United States in an orchard being treated for insects. It is used (ca 1993) as an abscising agent to thin apples. 

Denisova A.V., Voronova L.D., Shilova S.A. Otsenka opasnosti insektitsida sevina dlya dikikh zhivotnykh nazemnykh ekosistem razlichnykh prirodnykh zon (An Evaluation of the Danger of the Insecticide Sevin for Wild Animals in Land-Based Ecosystems in Different Natural Zones) / / Vliyaniye pestitsidov na dikikh zhivotnykh nazemnykh i vodnykh ekosistem (Pesticide Effects on Wild Animals of Land- and Water-Based Ecosystems). Moscow, 1977. P. 27-57. 

Stewart, N.E., Millemann, R.E., and Breese, W.P. Acute toxicity of the insecticide sevin and its hydrolysis prodnet 1-naphthol to some marine organisms. Trans. Am. Fish. Soc., 96(l) 25-30, 1967. 

DDT can be determined in microgram amounts by its inhibition of carbonic anhydrase (69). Several of the chlorinated insecticides as well as the carbamate insecticide, Sevin, are potent lipase inhibitors. As little as 0.1-1 /Ag/ml of Sevin, aldrin, heptachlor, lindane, 10 / g/ml of DDT, and 2,4-d can be determined fluorimetrically with 2-3% precision by the lipase inhibition when 4-methyl umbelliferone heptanoate is used as substrate (70). The lipase inhibition procedure for DDT determination is much easier to carry out than the carbonic anhydrase assay which involves monitoring gaseous COo production. 

The carbamate insecticide sevin is a widely used poultry insecticide. This compound is relatively safe, but deaths have been reported in turkey poults kept on premises where the product has been excessively applied at 10 times the recommended rate. The clinical signs are similar to those caused by organophos-phate insecticides. 

Methyl isocyanate, widely known because of its tragic implication in the Bhopal disaster, is used for the manufacture of several insecticides and herbicides including the carbamate insecticide "Sevin", (4.6), Equation (4.5) produced by Union Carbide and accounts for about three-quarters of all monoisocyanates manufactured [351]. 

Dorough, H. W., and CasLda, I. E, (1964), Nature of certain carbamate metabolites of the insecticide Sevin. J. Agric. Food Chem. 12, 294. 

Thus, the persistence of the carbamate insecticides, Sevin and baygon, in natural water is affected by the different environmental conditions. The two compounds are readily hydrolyzed in slightly alkaline waters they are also slightly adsorbed on mineral particulate matter common in streams and are slowly decomposed by solar ultraviolet radiation. Also, these compounds and their hydrolysis products are readily used by the microbial flora present in natural waters. Pyrolan and dimetilan, however, are expected to persist for long periods of time in natural waters these compounds are resistant to chemical hydrolysis under normal pH conditions of stream waters and are not readily used by the aquatic microorganisms. Still, pyrolan is partially removed by adsorption on mineral suspended solids of a high montmorillonite content. 

Starting with 1-naphthol, suggest an alternative synthesis of the insecticide Sevin to the one given in Section 17.9A. 

PROBLEM 14.15 The highly effective, biodegradable insecticide Sevin is a urethane called 1-naphthyl-N-methylcarbamate. It is made from methyl isocyanate and 1-naphthol. Using eq. 14.28 as a guide, write an equation for its preparation. 

A contact insecticide with the trade name Sevin . White solid, m.p. 142 C. It is prepared by reaction of I-naphthol with methyl isocyanate or with phosgene and a base. 

Naphthol is mainly used in the manufacture of the insecticide carbaryl (59), l-naphthyl A/-methyicarbamate/ iJ-2j5 - (Sevin) (22), which is produced by the reaction of 1-naphthol with methyl isocyanate. Methyl isocyanate is usually prepared by treating methylamine with phosgene. Methyl isocyanate is a very toxic Hquid, boiling at 38°C, and should not be stored for long periods of time (Bhopal accident, India). India has developed a process for the preparation of aryl esters of A/-alkyl carbamic acids. Thus l-naphthyl methylcarbamate is prepared by refluxing 1-naphthol with ethyl methylcarbamate and POCl in toluene (60). In 1992, carbaryl production totaled > 11.4 x 10 t(35). Rhc ne-Poulenc, at its Institute, W. Va., facihty is the only carbaryl producer in United States. 

Monoethylamine is used in the synthesis of Sevin, an important insecticide. Trimethylamine has only one major use, the synthesis of choline, a high-energy additive for poultry feed. 

The line drawing and chemical formula of Sevin, a common insecticide, appear in the margin. Determine the molar mass of Sevin. 

Aly, O.M. and El-Dib, M.A. Studies on the persistence of some carbamate insecticides in the aquatic environment. I. Hydrolysis of sevin, baygon, pyrolam and dimetilan in waters. Water Res., 5(12) 1191-1205, 1971. 

Best EM Jr, Murray BL Observations on workers exposed to Sevin insecticide A preliminary report. 7 OccupMed 10 507-517,1962... 

In the 1950s Kolbezen and Metcalf at the University of Califomia-Riverside laid the foundation for Union Carbide s development of carbaryl (Sevin ), the first major carbamate. Still the most important carbamate insecticide, it is made by condensing 1-naphthol with methyl isocyanate. The... 

At Bhopal they were manufacturing SEVIN, also called carbaryl, a broad-spectrum insecticide that was and still is used on many crops throughout the world. The reaction steps to manufacture SEVDSf are shown in Figure 10-16. 

Uncharged carbamates, such as carbaryl (8.20, sevin), can penetrate the CNS of insects (which do not use AChE in their neuromuscular junction) and they act quite selectively as insecticides with a low toxicity to mammals (median lethal dose [LDjg] in the rat = 540 mg/kg, p.o.). Many useful insecticides can thus be found in this group. Malathion (8.21) is a pro-drug, since the thiophosphate must be bioactivated to the phosphate form—a transformation carried out by insects but not mammals. Additionally, the ester groups of malathion are rapidly hydrolyzed in higher organisms to water-soluble and... 

DP Jonhson, HA Stansbury. Adaptation of sevin insecticide (carbaryl) residue method to various crops. J Agric Food Chem 13 235-327, 1965. 

The most common adsorption systems consist of silica gel or alumina adsorbents in association with an organic solvent system. The adsorbent can exert a considerable influence on the separation of compounds. Alumina and silica gel, for example, have significantly different properties and can result in quite different separations. Activation of the adsorbent also influences sample retention. The presence of water on the adsorbent decreases the adsorbent activity due to blockage of active sites. If large quantities of water are present, a partition system may be set up which may extensively change the retention times due to the different chromatographic principle involved. Table 2.1 compares results obtained for the separation of the insecticide carbaryl (Sevin) and its hydrolysis product 1-naphthol on alumina and silica gel. Comparisons between activation and deactivation are made. The results show that separation of the two components is reversed with the two adsorbents examined. In most cases, activation of the plates caused the/ f values to increase relative... 

The development of Sevin and related insecticides resulted from studies on the alkaloid physostigmine, which has a methyl carbamate portion. These studies also led to the development of potent nerve gases such as Sarin . 

Propose a mechanism for the reaction of methyl isocyanate with 1-naphthol to give Sevin insecticide. 

The application of pesticides is also limited by regulation, which imposes wide buffer zones, and by community.action to veto pesticide application. Carbaryl (1-naphthyl N -methyl carbamate, Sevin ), acephate (0, S-dimethyl acetylphosphoroamido-thioate, Orthene ), diflubenzuron (N -[ [(A-chlorophenyl)amino]-carbonyl]-2,6-difluorobenzamide, Dimilin ), and other insecticides are effective against the larvae. 

The development of resistance by certain insect species to chlorinated hydrocarbon insecticides aroused research into alternative chemical classes of compounds. This research led to the development of the carbamates as useful broad-spectrum insecticides. The best known of this class is carbaryl (Sevin), which has emerged as one of the most extensively used insecticides. 

Our first objective was to determine whether microencapsulated methyl parathion Is unique In Its property to be carried back to the hive by bees. To that end a mixture of three commonly used insecticides along with MMP was applied to a plot of blooming rape. The agents were azlnphos-methyl (Guthlon), parathion, and carbaryl (Sevin). By using a mixture on a single plot the effects of variation In bee visitation were eliminated and the tendencies to be carried to the hive could be measured by the relative residue levels in the pollen samples. Five applications were made over a period of seventeen days. Pollen samples were collected from hives placed near the field after two, three, four, and five successive applications approximately two days after each application was made. The application rates were doubled for the last two applications. The data are shown In Table I. 

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