Fumigant

Fumigant, also known as fumigant insecticide, refers to a chemical agent that easily becomes a vapor at normal temperature and pressure and is poisoned by steam to kill pests and harmful bacteria. Vapors generally enter the body through the respiratory system or skin of the pest. It is used to prevent various pests lurking in houses, warehouses, airplanes, cars and boats. In agriculture, pests, mites and germs that are used to smoke seeds, store grain, fruit trees and seedlings can also be used for soil disinfection. In the case of insecticide, the toxic gas volatilized by the poison is mixed in the air to reach a certain concentration, and enters the inside of the tissue through the respiratory system of the pest. After a certain period of time, it causes poisoning and death. Due to the large mobility of gas molecules, the physical properties of the penetration and diffusion forces are also large, can penetrate into any gaps, and achieve the highest insecticidal effect in the shortest time. In the fumigation process, fumigation and insecticidal effects are often impaired by the influence of other factors, including the physical and chemical properties of the fumigant itself (such as vapor pressure, permeability, molecular diffusion, concentration, etc.), the degree of containment of the fumigation chamber, and fumigation. The object's sorption to poison gas (absorption and adhesion properties), the distribution of toxic gas in the fumigation space, the length of fumigation time, the temperature and humidity, and the carbon dioxide and oxygen content. Most fumigants are liquids and can be classified into halides (most quantities), cyanides, phosphides, and others by chemical composition. The main varieties are bromoformamide, carbon tetrachloride, chloropicrin Cl3NO2, 1,2-dichloroethane, hydrogen cyanide, acrylonitrile, aluminum phosphide, methyl formate, ethylene oxide, naphthalene and camphor. . Among them, methyl bromide, ethylene oxide, methyl formate and the like have a low boiling point, and the vapor pressure is high at normal temperature, and the phosphide absorbing water liberates phosphine gas, which has good insecticidal and bactericidal effects and is commonly used. Fumigant. Only when the concentration of the fumigant in the air is greater than the lethal concentration of the pest can the poisoning effect be exerted. Therefore, fumigants are generally suitable for confined spaces with a certain temperature, such as controlling granaries, warehouses, warehouses, vegetable greenhouses or vehicles, various pests and bacteria in the ship. Pests used in agriculture to fumigate seeds, fruit trees, seedlings, etc., are also used for soil disinfection. Many fumigants are very toxic to humans and animals. Dibromoethane, which has been banned, is also a strong carcinogen. When using fumigants, care must be taken to prevent poisoning.