DMF

Application of DMF in the pesticide industry (Highly effective insecticide - Imidacloprid)

Imidacloprid is a nitryl methyl group of internal absorption insecticide, is a nicotinoyl chloride insecticide, also known as neonicotinoid insecticide. It has broad spectrum, high efficiency, low toxicity and low residue, it is not easy for pests to produce resistance, and has multiple effects such as touch, stomach toxicity and internal absorption. After the pest contact with the drug, the normal conduction of the central nervous system is blocked, causing it to paralyze and die. The product has good quick effect, and has a high prevention effect after 1 day. The drug effect is positively correlated with temperature, and the insecticidal effect is good when the temperature is high. It is mainly used for the control of stinging and sucking mouth pests, and occupies a very important position in the global plant protection industry

Imidacloprid is mainly used for the control of stinging and sucking mouth pests (can be rotated with acetamidine at low temperature - imidacloprid for high temperature, acetamidine for low temperature), control such as aphids, plantworms, whiteflies, leaf hoppers, thrips; It is also effective against certain pests of Coleoptera, diptera and lepidoptera, such as rice weevil, rice negative mud worm and leaf miner moth. But not against nematodes and starscream. It can be used for rice, wheat, corn, cotton, potato, vegetables, sugar beet, fruit trees and other crops. Because of its excellent absorption, it is especially suitable for seed treatment and granule application. Generally, 3~10 grams of effective ingredients are used in mu, mixed with water spray or seed mixing. The safety interval is 20 days. Pay attention to protection when applying medicine, prevent contact with skin and inhalation of powder and liquid medicine, wash exposed parts with water in time after using medicine. Do not mix with alkaline pesticides. Do not spray in strong sunlight, so as not to reduce the efficacy.

At present, the industrial production process of imidacloprid mainly uses 2-chloro-5-chloromethyl pyridine and n-nitroimidazolidane (imidazolidane for short) as starting materials, and directly synthesizes the target product imidacloprid through a one-step reaction in dimethylformamide (DMF). The existing industrial post-treatment (purification) steps of the production process are as follows: 1. The reaction liquid is distilled under pressure and 90% to 95% (v/v) DMF is steamed; 2. Extractant dichloroethane was added to the concentrated liquid after distillation for extraction separation to obtain dichloroethane solution of imidacloprid and imidazolidane, and then water vapor was introduced into the dichloroethane solution of imidacloprid. In the process of water vapor introduction, the low boiling point of dichloroethane was used to recover dichloroethane by condensation, and the emulsion of imidacloprid was obtained; 3. Imidacloprid product and imidazolidin-containing aqueous solution (containing a small amount of DMF) are obtained by filtration and separation of imidacloprid emulsion while hot; 4. The imidazolidine-containing aqueous solution is cooled and then imidazolidine-containing wastewater containing a small amount of DMF is separated. After distillation and separation, water, DMF and a small amount of high boiling substance are obtained.