Pesticide intermediate is a product produced by processing raw materials for agricultural use, and is an intermediate medium that combines two or more substances together. In the pesticide can be understood as synergist, is the production of pesticide intermediate materials.
Common types: plant growth regulators: aminoglutethimide (DA-6), chlorpyrifos (KT-30), sodium compound phenol, 6-BA, cytokinin, sodium α-naphthalene acetate, sodium 5-nitroguaiacol, indole butyric acid, etc.
Pesticide intermediates in the pesticide can be understood as synergists, is the production of pesticides intermediate materials. It is also the product produced by processing agricultural raw materials, is a kind of intermediate medium that combines two or more substances together. In our country pesticide intermediates can generally be divided into two categories, pesticide intermediates containing heterocyclic and pesticide intermediates containing fluorine.
1、Pesticide intermediates containing heterocyclic
(1) intermediates containing heterocyclic organophosphorus insecticides, including diazinon, chlorpyrifos, quinpirole, chlorpyrifos, chlorazaphos intermediates.
(2) Intermediates of high efficiency insecticides containing heterocyclic rings, including imidacloprid, imidacloprid, retrinex, fluazifop, intermediates of fluazifop.
(3) intermediates of highly effective fungicides containing heterocyclic ring, including intermediates of quinoxaprop and furopyradifen.
(4) intermediates of herbicides containing heterocyclic, including intermediates of general sulfonylurea herbicides, intermediates of imidazolinone herbicides imidacloprid, mefenoxam, and intermediates of diclofenac, dichloroquinolinic acid, butazolidinone.
2、Pesticide intermediates containing fluorine
In the search for ways to improve biological activity, often use fluorine instead of hydrogen or chlorine. This substitution can greatly improve the efficacy of pesticides, the introduction of fluorine atoms in the structure of pyrethroids, will improve the efficacy of pests, and acaricidal effect, so fluorine-containing pyrethroids have been paid attention to. However, it is necessary to select the right position of fluorine substitution in the molecule to prepare the most active compound. Fluorine atom insertion plays a key role in biological activity, but fluorine substitution for hydrogen often reduces activity, however, the most active compounds often contain fluorine atoms at certain positions in the molecular structure, while fluorine-containing intermediates are necessary to prepare highly active fluorinated compounds, so research and development of fluorine-containing intermediates are essential.
1、Environmental friendly
The relationship between biodegradability and its molecular structure is generally as follows: high linearity of hydrophobic group is easy to degrade; the length of hydrophobic chain has influence on degradability; short ethoxy chain is easy to degrade; increase the distance between sulfonic acid group and hydrophobic group end, alkyl benzene sulfonate is easy to degrade. For anionic emulsifiers, alkyl sulfonates (AS) are the most degradable. Straight-chain alkyl benzene sulfonates (LAS) with a chain length of C6 to C12 are the most degradable. Alkyl chains with branched chains and the closer the length to the main chain, the more difficult to degrade. For non-ionic emulsifier, short-chain alkyl, straight-chain alkyl, no phenolic group in the molecule, PO and EO unit number is easy to degrade, the same length EO chain than PO chain easy to degrade.
2、Safety
The toxicity of anionic emulsifiers are relatively low, for AS, carbon number less than 8 or more than 14 than its congeners less toxic. The vast majority of nonionic emulsifiers are less toxic than anionic ones, the lowest is polyethylene glycol type (PEG), the next is sugar esters, fatty alcohols polyoxyethylene ether (AEO) and sorbitol fatty acid esters and their dehydrated and ethylene oxide adducts (Span, Tween). For EO-type nonionic emulsifiers, the general ester type (Tween, a polyoxyethylene compound of sorbitol lost) is less toxic than the ether type (AEO and alkylphenol polyoxyethylene ether APEO). Polyol type such as sorbitol esters, glycerol esters, etc. can be expected to be basically non-toxic.
3、Mildness
The order of skin irritation of some anionic emulsifiers: ABS (L AS) > AS > AOS (α-alkenyl sulfonate) > AES (fatty alcohol polyoxyethylene ether sulfate). Comparing the skin irritation intensity of AS, LAS and AOS with different chain lengths, overall, the emulsifiers with C10-14 are more irritating to the skin, and the chain length of C12 is the most irritating. The irritation of Tween in EO-type nonionic emulsifiers is less than that of AEO; various homologues of EO-type emulsifiers, the irritation decreases as the number of EO added increases. Intramolecular introduction of polyethylene glycol (PEG) groups can greatly reduce the irritation of emulsifiers.
China is the main producer and supplier of pesticide fine chemical intermediates in the world, with a very promising development prospect. Among them, 1,2,4-trichlorobenzene, o-cresol, catechol and nonylphenol are the most important pesticide intermediates. 1,2,4-trichlorobenzene is mainly used in the synthesis of pesticide dicamba, carbofuran, sodium pentachlorophenate, pentachlorophenol, etc.; o-cresol is mainly used in the synthesis of high efficiency herbicides; catechol is an important intermediate of low toxicity and high efficiency new carbamate pesticides furadan, residual carbofuran, etomidate; nonylphenol is A multi-purpose non-ionic surfactant, widely used in pesticide emulsifier; m-cresol is mainly used in the synthesis of pesticide insecticides.
In recent years, due to the gradual strengthening of the development and application of its downstream products at home and abroad, the demand for high purity 1,2,4-trichlorobenzene in the international market is strong. In addition, due to the ban and restrictions on the use of lindane, in foreign developed countries and regions, the traditional trichlorobenzene raw materials are increasingly reduced, and the production of organic chlorine products is also gradually reduced, which also leads to the current global supply of trichlorobenzene, especially high-purity 1,2,4-trichlorobenzene is tight. All these factors provide good opportunities for the development of 1,2,4-trichlorobenzene production in China.
New carbamate insecticides produced by catechol, such as furadan, residual carbofuran, etomidate, etc., due to low toxicity, good results, recommended by the World Health Organization as the excellent varieties of household pests and storage pest control agents, market demand will also gradually increase.
Nonylphenol is the largest product in alkyl phenols, with good decontamination, wetting and penetration, dispersion, solubilization emulsification and other functions, is widely used in pesticide emulsifier, is the most important intermediate in the petrochemical industry and organic synthesis industry. The market demand for m-cresol, the growth rate is basically maintained at an annual average of 8% to 10% level, the development rate is stable.
In addition, because the fine chemical industry has the advantages of functionalization, high performance, special flowers, high value-added, is a low-carbon, environmentally friendly process, is to achieve the national goal of energy saving and emission reduction, the development of a low-carbon economy a general path, the country’s attention to its greatly increased. The development of fine chemical pesticide intermediates industry is also very favorable.
Therefore, China’s fine chemical pesticide intermediates industry has very good development prospects under the dual favorable influence of increased market demand and government encouragement for development.
Diethyl maleate is also a pesticide intermediate, used in the preparation of organophosphorus pesticide malathion, and also used in the production of fragrances.