Develop Pesticide Intermediates to Make this Industry Bigger and Stronger
With the increasing refinement and serialization of pesticide production, the development of pesticide intermediates industry is of great significance to promoting the development of pesticide industry. According to the three-factor principle of “the market is the premise, raw materials are the foundation, and technology is the key”, accelerating the development of the pesticide intermediates industry is the guarantee for the pesticide industry to become bigger and stronger. If the development of pesticide intermediates industry lags behind, it will seriously affect and restrict the development of pesticide industry. According to the < 2017-2022 China Pesticide Market Investment Analysis and Prospect Forecast Report released by China Investment Consultants> pyridines and their derivatives, o-phenylenediamine, 1,2,4-trichlorobenzene, catechol, m-cresol, nonylphenol, sulfoxide chloride and other intermediates have broad prospects for development, and it is recommended to accelerate the development speed of these pesticide intermediates. The pesticide intermediates that are optimistic about the market are introduced as follows:
2,3-Dichloropyridine is a key intermediate in the production of the novel insecticide chloranthramide. Chlorantranoid benzamide is efficient, broad-spectrum, is DuPont’s flagship product, it has a good control effect on lepidoptera noctuidae, moth family, borer moth family, leaf curl moth family, powder moth family, cabbage moth family, wheat moth family, fine moth family, etc., and can also control coleoptera weevilaceae, leaf beetle family, dipteropod diving fly family, powdery mildew and other non-lepidoptera pests. Because the chemical structure of chlorantraniliprox parametamide has a new insecticidal principle that no other insecticide has, it can efficiently activate the muscle receptors of insect fish nitrates, over-release calcium ions in the “calcium library” in cells, resulting in paralysis and death of insects, high larval activity against lepidopteran pests, wide insecticidal spectrum, and good efficacy. According to the current experimental results, the activity of chlorantranose benzamide on target pests is 10-100 times higher than that of other products, and can lead to disturbances in the mating process of some lepidopteran insects. Studies have proved that the product can reduce the spawning rate of a variety of noctuidae pests, due to its good efficacy and resistance to rain erosion biological characteristics, these properties are actually a combination of permeability, conductivity, chemical stability, high insecticidal activity and cause pests to stop feeding immediately. Therefore, it is determined that it has a longer, more stable and more environmentally friendly effect than most other pesticides currently in use, thus achieving a protective effect on crops.
The main production route is niacinamide as the starting material, after the degradation of Hoffmannamide, rechlorination, diazotation, Sandmeyer reaction, you can get 2,3-dichloropyridine. The yield was 62% in nicotinamide and more than 99% in 2,3-dichloropyridine. In addition, there is a production route with 3-aminopyridine as the main raw material, the intermediate products are not purified, and the “one-pot method” is adopted to synthesize 2,3-dichloropyridine. The method is simple to operate and easy to industrially produce. The yield was 66% in terms of 3-aminopyridine, and the content of 2,3-dichloropyridine reached more than 98%.The export prospects of 2,3-dichloropyridine are very promising.
2. 2-Chloro-3-pyridinecarboxylic acid
2-Chloro-3-pyridinecarboxylic acid is an important intermediate in the production of a novel heterocyclic herbicide substituted with pyridine. The synthesis of pyrolamide and nicosulfuron, which is currently popular in the market, is inseparable from it. Due to its special physiological activity, it is increasingly attracted by the industry as an intermediate with the most market potential.
Pyrfloxacin is a carotenoid biosynthetic inhibitor and is a broad-spectrum selective wheat field herbicide that causes chlorophyll destruction and cell rupture, causing plant death. Apply 125~250g/ha to autumn sown wheat and barley fields before or after sprouting to prevent grasses and broad-leaved weeds, especially pig plague, porcupine and viola weeds. This agent has the following characteristics: wide herbicide spectrum, can prevent malignant weeds, soil Traditional Chinese medicine has a long efficacy period, stable efficacy, and can be mixed with other herbicides. After the application of the agent, a layer of anti-leaching medicinal soil layer is formed on the soil surface, and it remains active throughout the growth period of the crop, when the weed germinates through this medicinal soil layer, it contacts and absorbs the agent, and the weed root system can also be absorbed if it comes into contact with the medicinal soil layer. In short, it can control most of the annual broad-leaved weeds and is also effective against grass sedges. If mixed with other applicable grass herbicides, the herbicidal spectrum can be expanded.
Chimney sulfuron is an assortive herbicide that absorbs weed stems and roots and then conducts in plants, causing growth arrest in sensitive plants, fading greenery of stems and leaves, gradually withering to death, generally 20 to 25 days of death, but in the case of lower temperatures, it takes longer for some perennial weeds. The efficacy of the application before the 4-leaf stage after budding is good, but the efficacy of the application decreases when the seedlings are large. The drug has pre-bud herbicide activity, but the activity is lower than that of post-bud, and it can control annual and perennial grasses and some broad-leaved weeds. Experiments have shown that weeds with strong sensitivity to medicine are barnyard grass, dogtail grass, wild oats, amaranth, and weeds with medium sensitivity include Honsophora, Lycopoda, purslane, duck tongue grass, cang ear and alfalfa, sedge, less sensitive weeds mainly quinoa, dragon flower, duck toe grass, ground skin and weed petal flowers.
At present, there are two main synthetic routes for the domestic production of 2-chloro-3-pyridine formic acid: one is based on the existing pyridine “parent”, directly “chlorinated” on the pyridine ring or introduced related “functional groups” to synthesize “purpose products”, and the other is to select suitable “active” straight-chain compounds to synthesize “objects of interest” through “grafting” and “closed loop”. But their advantages and disadvantages are mainly manifested in: the former process route is simple, the cost is low, but the product purity is low, the latter product purity is high, but the process is complex, the investment is too high, and the cost is also high. At present, the domestic popular production route is mainly the use of “niacin process route”, and some use the “acrolein cyclization” process route.
Pentachloropyridine is a very important pesticide raw drug intermediates, in China’s pesticide industry has been widely used, can be used to produce chlorpyrifos, dichloropyridic acid, fluorocarbon smoke and other insecticides, fungicides, herbicides original drugs, it is also an important pharmaceutical intermediate, can be used for the production of cardiovascular, cerebrovascular and other drug original drugs.
Chlorpyrifos has the triple effect of gastric poisoning, touch killing and fumigation, and has a good anti-effect on a variety of chewing and sucking mouthpart pests in rice, wheat, cotton, fruit trees, vegetables, and tea trees. Mixed compatibility is good, can be mixed with a variety of insecticides and the synergistic effect is obvious (such as chlorpyrifos and trizophos, avermectin, etc.). Compared with conventional pesticides, it has low toxicity and is safe for natural enemies, and is the preferred agent to replace highly toxic organophosphorus pesticides (such as 1605, methamidophos, Oxylego, etc.). The insecticidal spectrum is wide, it is easy to combine organic matter in the soil, and it has a special effect on underground pests for a period of more than 30 days. No absorption effect, to ensure the safety of agricultural products, consumers, suitable for the production of pollution-free high-quality agricultural products.
Dichloropyridine is a synthetic plant growth hormone that is chemically similar to many natural plant growth hormones but has better persistence within the tissues of plants. It is mainly absorbed by the roots and leaves of the plant and then conducted in the plant, so its conduction performance is strong. After applying the weed, it is absorbed by the leaves or roots of the plant, moves up and down in the plant body and is rapidly transmitted to the entire plant. Low concentrations of dichloropyridine can stimulate the synthesis of DNA, RNA and proteins in plants, resulting in uncontrolled and disorderly growth of cell division, and finally leading to the destruction of tube bundles, while high concentrations of dichloropyridine can inhibit cell division and growth.
Fluoroacetinum is a herbic acid herbicide of the pyridineacetic acid class. It has an assorption conduction effect and has a typical hormonal herbicide reaction. After seedling use, sensitive crops appear reacting with typical hormonal herbicides. It can be used for wheat, barley, corn, grapes and orchards, pastures, forest farms and other places to control broad-leaved weeds, such as pig plague, field spin flowers, cabbage, multiplication, curly stem amaranth, purslane and other weeds.
The production route of pentachloropyridine was prepared by condensation of potassium carbonate, 2-chloro-5-chloromethylpyridine and excess imidazoline with dimethylformamide as the solvent and quaternary ammonium salt as the catalyst to produce 1-(6-chloro-3-pyridinylmethyl)-N-nitroimidazolium-2-imine. Under the catalysis of quaternary ammonium salts, dmF (dimethylformamide) as the solvent, the use of imidazoline excess to maximize the inhibition of the synthesis of side reaction double substitution products, to obtain 1- (6-chloro-3-pyridinyl methyl) – N- nitroimidazolium-2-imino, the reaction process cycle is short, the product content, that is, purity can reach 97%, yield up to 90%. Of course, under the existing conditions, there are many methods of synthesizing pentachloropyridine, and enterprises can take different synthetic routes according to their own equipment and process conditions.
Pentachloropyridine application field is constantly expanding, it can be widely used in pesticide insecticides, fungicides, herbicide synthesis, can also be applied to the production of medicine, the application prospect is very broad.
2-Methylpyridine can be used for synthetic herbicides, veterinary drugs, nitrogen fertilizer synergists, rubber additives, dye intermediates, film photosensitive materials, pharmaceutical chlorpheniramine, long-acting sulfonamides, local anesthetics and laxatives, etc. Recently, 2-methylpyridine has been developed to synthesize important pesticide intermediates 2-hydroxy-3,5,6-trichloropyridine, 2-trifluoromethyl-6-chloropyridine, 4-amino-3,4,5-trichloropyridine-2-carboxylic acid and other promising products. In addition to the above uses, 2-methylpyridine is mainly used in the production of 2-vinylpyridine and 2-methyl-5-vinylpyridine, 2-vinylpyridine or 2-methyl-5-vinylpyridine with butadiene, styrene emulsion copolymerized as a rubber skeleton material impregnated butylpyrhex, of which 2-vinylpyridine or 2-methyl-5-vinylpyridine accounts for 15% of the composition of butylidean latex, at present, only a very few domestic enterprises produce vinylpyridine on a small scale, so domestic butyropyridoxine mainly depends on imports.
3-Methylpyridine is the most important and widely used pyridine derivative product. In the pesticide industry, the herbicides pyrifloxam, pyrifloxamide, hydroxypentarin, chicosine xanthanol, acrylic xanthanolone, etc., synthetic insecticides include imidacloprid, styrenol, alenopherolamine, thiacloprid, acetamidine, TI-304 and dozens of varieties, synthetic fungicides include pyrimidine, flufenamide, etc., rodenide rodenide, vitrenic nitrile, rodentide, etc. Among them, pyrifloxam is the leading variety of herbicides in the United States, Japan and others. Imidacloprid is one of the three major varieties of highly effective new insecticides in the world. In addition, many pesticides have formed a series of products, such as a series of pyridine-containing pyrethroids, pyridine diarylether herbicides, pyridine-containing sulfonylurea herbicides, pyridine benzoylurea insecticides, pyridine-containing nicotinylene insecticides and other new pesticides. In the pharmaceutical industry, 3-methylpyridine is used to synthesize niacin, niacinamide, vitamin B, nicolamine and cardiotonic drugs, etc. Niacin and niacinamide are also used in the feed industry in large quantities in addition to medicine. In recent years, niacin has developed rapidly in China, there have been several enterprises planning to build or are building large-scale niacin plants, Swiss Longsha company as early as 1998 in Guangzhou joint venture to build a 3400t / a niacin device, all products exported. In other industries, 3-methylpyridine can also be used to synthesize fragrances, dyes, daily chemicals, etc. 3-methylpyridine can synthesize a variety of serialized derivative products, most of which are high value-added, specialized fine chemical intermediates, such as 2-chloro-5-pyridine, 2-chloro-5-chloromethylpyridine, 2-chloro-5-trifluoromethylpyridine, 2-chloro-3-trichloromethylpyridine, 2,3-dichloro-trifluoromethylpyridine, 2-chloronicotinic acid, 5-chloronicotinic acid, 3-pyridinecarbonitrile, 3-pyridinemethanol, 3- New uses for pyridinecarboxaldehyde, 3-pyridinemethanol, etc., 3-methylpyridine are under continuous development. Analyzing the changes in domestic market demand, the hot spot of 3-methylpyridine consumption is beginning to shift, and the original main consumption area of niacin, niacinamide, is shrinking in demand, and will be replaced by a booming pyridine pesticide.
4-Methylpyridine is used in the pharmaceutical industry for the synthesis of isoniazid, antidotes double compound phosphorus and double phosphorus, and is also used in pesticides, dyes, rubber additives, synthetic resins and other fields. In particular, 4-vinylpyridine synthesized by 4-methylpyridine can be copolymerized with styrene, acrylonitrile or acrylate to obtain polyvinylpyridine, as a paper enhancer and modifier, and polyvinylpyridine can be alkylated with bromomethane to obtain an important weak alkaline ion exchange resin.4-methylpyridine can also be used to synthesize tuberculosis prevention drug isoniazid, due to the global tuberculosis incidence rate in the past decade has shown a significant upward trend, as a highly effective drug isoniazid against tuberculosis, has good development prospects
7. 2-chloropyridine and 2,6-dichloropyridine
2-Chloropyridine derivative pyridine thiose copper zinc in the field of daily chemicals is mainly used for the synthesis of drugs to prevent and treat dandruff, in the pharmaceutical industry, with 2-chloropyridine as raw material can synthesize histamine antagonist drugs pheniramine, antihistamine drugs chlorobenemamine maleate, antiarrhythmic drugs diisopropylpamide, central nervous system stimulant methyl acetidate, cough and sputum suppressant pyridineethylamine, etc. Pesticide industry, pyridinone synthesized by pyridine is a highly efficient and low toxicity of bactericidal anti-mildew agent, widely used in chemical, coating, water treatment and other fields, its sodium salt is a name of 10,000 acres of efficient fungicide, used in a variety of crops, and is an excellent fungicide for silkworms, 2-chloropyridine derivative 2-chloro-4-aminopyridine is a new urea plant growth regulator key monomer, by 2-chloropyridine can also synthesize a variety of high-efficiency pesticides.2,6-dichloropyridine is an important specialized fine chemical intermediate, Mainly used for the synthesis of specific medicines and pesticides, 2,6-dichloropyridine itself can be used as a fungicide, it is hydrolyzed with sodium hydroxide, and then chlorinated to give 3,5,6-trichloro-2-pyridinol, which is used to synthesize O, O-diethyl-O-3,5,6-trichloro-2-pyridinyl phosphate, in addition to the synthesis of important fragrance musk pyridine and other products.
8. Other derivatives of the pyridine class
Pyridine also has many important derivative products, such as hexahydropyridine is an important chemical raw material, mainly used for the production of anesthetics, painkillers and plant growth regulators pomfrin, 3-ethylpyridine, 2,5-dimethylpyridine, acetylpyridine is a promising new heterocyclic fragrance that can be used in tobacco and food, 2,6-dimethylpyridine can be used for the production of cardiovascular drugs hematogen, anthelmintic repellent, cortisone acetate, hydrocortisone, etc., 2,3,5- Trimethylpyridine is the key to the synthesis of a new anti-ulcer drug omeprazole, 2,4,6-trimethylpyridine is used for the synthesis of oral contraceptives megesterone, vitamin A, 2,3-difluoro-5-chloropyridine is used for the synthesis of Novartis newly developed herbicide alkyne ester, etc., in addition to bromopyridine, polychlorinated pyridine, hydroxypyridine, aminopyridine and other serial pyridine derivatives are widely used and have great development potential.
O-phenylenediamine has a wide range of applications in pesticide synthesis, not only can synthesize carbendazim, methyl thiophanol and other market-widely used fungicides, but also can synthesize a variety of benzimidazolium ring structure of new fungicides. In recent years, the market demand for o-phenylenediamine is expanding year by year, and its development prospects are very promising.