Intermediate is also called organic intermediate. Coal tar or petroleum products are used as raw materials to produce intermediates such as dyes, pesticides, pharmaceuticals, resins, additives, plasticizers, etc. It was originally used in the manufacture of dyes, also known as dye intermediates.
type
Intermediates refer to semi-finished products, which are intermediate products in the production of some products. For example, if you want to produce a product, you can produce it from intermediates to save costs.
Intermediates are formed by sulfonation, alkali melting, nitration, reduction and other reactions of cyclic compounds such as benzene, naphthalene, anthracene, etc. For example, benzene is nitrated into nitrobenzene, and then reduced to aniline. Aniline can be chemically processed into dyes, drugs, vulcanization accelerators, etc. Nitrobenzene and aniline are intermediates.
There are also acyclic compounds such as methane, acetylene, propylene, butane, butene, etc. through dehydrogenation, polymerization, halogenation, hydrolysis and other reactions. For example, butane or butene is dehydrogenated into butadiene, and butadiene can be chemically processed into synthetic rubber, synthetic fiber, etc. Butadiene is an intermediate.
Initially, it refers to the intermediate products produced in the process of synthesizing chemical products such as spices, dyes, resins, drugs, plasticizers, rubber accelerators, etc. with coal tar or petroleum products as raw materials. It now refers to various intermediates obtained in the process of organic synthesis.
Pharmaceutical supplies
concept
The so-called pharmaceutical intermediates are actually some chemical raw materials or chemical products used in the process of pharmaceutical synthesis. This chemical product can be produced in ordinary chemical plants without a drug production license. As long as it reaches a certain level, it can be used for the synthesis of drugs.
effect
Pharmaceutical production requires a large number of special chemicals, most of which were originally produced by the pharmaceutical industry itself. However, with the deepening of social division of labor and the progress of production technology, the pharmaceutical industry has transferred some pharmaceutical intermediates to chemical enterprises for production. Pharmaceutical intermediates are fine chemical products. The production of pharmaceutical intermediates has become a major industry in the international chemical industry.
In cell biology, intermediate refers to the middle of the gradually disintegrating spindle near the equatorial plane at the late stage of cell division. The concentration of cytoplasm around it increases and fills the whole equatorial plane. This area of concentration is called intermediate.
β－ Lactams
1. Current situation
β－ After nearly 50 years of development, lactam antibiotics have formed a complete production system. Almost all β－ Lactam antibiotics (except those within the patent period) can be produced in China, and the cost is very low. The output of penicillin ranks first in the world, and a large number of them are exported to the international market; Cephalosporins are basically self-sufficient, and some of them can be exported.
And β－ All the intermediates supporting lactam antibiotics can be produced by our country. Except that the mother nucleus 7-ACA and 7-ADCA of semi synthetic antibiotics need to be partially imported, all side chain intermediates can be produced and exported in large quantities.
with β－ Take phenylacetic acid, the main supporting intermediate of lactam antibiotics, as an example. There are nearly 30 phenylacetic acid manufacturers in China, with a total annual production capacity of about 20000 tons. However, most of the enterprises are relatively small, with the largest annual output of 2000 tons, and most of the others produce hundreds of tons. In 2003, the total domestic demand for phenylacetic acid was about 14000 tons, and the consumption structure was: Penicillin G accounted for 85%, other medicines for 4%, spices for 7%, pesticides and other fields for 4%.
With the development of domestic perfume, medicine, pesticide and other industries, the demand for phenylacetic acid will further increase. It is estimated that by 2005, China's pharmaceutical industry will consume about 14000 tons of phenylacetic acid, the pesticide industry will consume 500 tons, and the spice industry will consume about 2000 tons. Coupled with the consumption in other fields, it is estimated that the total domestic demand for phenylacetic acid will reach 18000 tons in 2005.
2. Gap
China has become the largest producer of antipyretics and analgesics in the world, with the output of aspirin, paracetamol, analgin and other varieties exceeding 10000 tons, and the output of phenacetin, aminopyrine, antipyrine and other varieties exceeding 1000 tons. At present, the output of antipyretic analgesics in China has increased rapidly, and it is expected to increase by about 8% in the future. The production of intermediates for antipyretic analgesics is large, and there are many manufacturers. With the growth of antipyretic analgesics, mesosomes have also achieved considerable development.
In 2003, domestic consumption of paracetamol increased rapidly, and exports also showed a rapid growth momentum. The export volume was 28163 tons, with a year-on-year increase of about twice. By the first half of 2004, although its export growth slowed down, it still increased. From January to May 2004, the export volume of paracetamol was 12501 tons, slightly higher than the same period in 2003. Paracetamol is an important intermediate in the synthesis of paracetamol, which grows rapidly. The annual output of paracetamol in China is about 32000 tons. It is estimated that by 2005, the domestic output of paracetamol will reach more than 50000 tons, and the pharmaceutical industry will consume 45000 tons of paracetamol. Coupled with the application in other fields, the total demand for paracetamol in 2005 was about 50000 tons, with a large market gap and broad prospects for development and utilization. The demand for phenylacetic acid continues to increase.
Fluorinated Pyridines
As of 2012, quinolone antibiotics that have been developed and put into mass production in China mainly include norfloxacin, ciprofloxacin, ofloxacin, enoxacin, lomefloxacin, fleroxacin, etc. Among them, the production of norfloxacin, ciprofloxacin and ofloxacin is the largest, accounting for about 98% of the total domestic production of fluoroquinolones.
Quinolones are generally synthesized from fluoroquinoline compounds synthesized from fluorobenzene rings and condensed with piperazine (or methylpiperazine). Due to the rich reserves of fluorite, China is one of the countries with the largest output of fluorinated drugs and intermediates in the world, and more than 80% of fluorinated intermediates are supplied for export. On the whole, fluorobenzene intermediates developed earlier in China, and the production capacity is generally surplus; Trifluoromethyl intermediates developed late and rapidly; For heterocyclic aromatic compounds, especially fluorinated pyridines, only a few research institutions and manufacturers in China have the synthesis technology of fluorinated pyridine intermediates. Therefore, fluorinated pyridine intermediates will become one of the main directions of domestic fluorinated intermediates research and development in the next few years.
application
O-chlorobenzoic acid
Mold inhibitor, it can prevent clothes from mildew and decay. Its main raw material is a kind of intermediate - o-chlorobenzoic acid. O-chlorobenzoic acid is an important intermediate in the pesticide, pharmaceutical and dye industries with a wide range of uses. It is mainly used in the synthesis of pesticides (sururea No. 1) and fungicides in pesticides. In medicine, it is mainly used in the synthesis of antipsychotics perphenazine, adrenocorticotropic drugs zenrubenzine and chuantong, antifungal drugs clotrimazole, chlorpromazine, ketamine and diclofenac. It is a standard reagent for alkalimetry and iodometry, Used as a preservative for adhesives and paints. In addition, it also plays an important role in dyes. We cannot do without taking photos every day. Everyone has his own photos. The body of the photos is film, and the body of the film can be made of o-chlorobenzoic acid. In chemistry, isomers often have similar chemical properties, so p-chlorobenzoic acid also has the same function as o-chlorobenzoic acid, and is also an intermediate of pesticides and pharmaceutical dyes. Because of them, life has more colorful beauty and eternal memory. It promotes the progress of life and improves the quality of life.
Hydroquinone
In contemporary life, mobile phones, televisions, refrigerators, and cars have become an important part of our lives. These products have brought many conveniences and highlights to our lives. Using mobile phones, you can chat and talk with friends and relatives in different places through a thin display screen. Using TV, you can see the customs and beautiful scenery all over the world, study and entertainment. Using refrigerators can prolong the freshness of food, and using cars can make our walking faster and more comfortable. An important part of these products is hydroquinone. Hydroquinone is an important organic intermediate, which can be used as rubber antioxidant and plastic antioxidant, as well as colorless vulcanized rubber products, food packaging rubber products and medical latex products. The tires on our vehicles, plastic bags for shopping, table tennis rackets for entertainment, rubber seals for food packaging, and medical gloves in hospitals can all be made of hydroquinone. In terms of synthetic polymers, due to its excellent heat resistance, it can be used as modified monomers of polyester, polyurethane, polycarbonate, polysulfone and epoxy resin to manufacture excellent engineering plastics and composite materials. In automobiles, engineering plastics are mainly used as bumpers, fuel tanks, instrument panels, body panels, doors, lamp covers, fuel pipes, radiators and engine related parts; In machinery, engineering plastics can be used for mechanical parts such as bearings, gears, lead screws and nuts, seals, and mechanical structural parts such as shells, covers, hand wheels, handles, fasteners and pipe joints; In electronic and electrical appliances, engineering plastics can be used for wire and cable coating, printed circuit board, insulating film and other insulating materials and electrical equipment structural parts; In household appliances, engineering plastics can be used in refrigerators, washing machines, air conditioners, televisions, electric fans, vacuum cleaners, electric irons, microwave ovens, rice cookers, radios, combined sound equipment and lighting appliances; In chemical industry, engineering plastics can be used in heat exchangers, chemical equipment linings and other chemical equipment, as well as pipes and pipe fittings, valves, pumps and other chemical pipelines. In addition to these, its high-purity products are mainly used to synthesize liquid crystal polymers. It is mainly used to make LCD of mobile phones, TVs and other electronic products.