Pharmaceutical intermediates are actually some chemical raw materials or products used in the synthesis process. Chemical products do not need that kind of production license. They can be produced in ordinary chemical plants. As long as they reach some grades, they can be synthesized appropriately.
Types of intermediates
Intermediates refer to semi-finished products, which are intermediate products in the production of certain products. For example, to produce a product, it can be produced from intermediates to save costs.
Intermediates are formed from cyclic compounds such as benzene, naphthalene, anthracene, etc. through sulfonation, alkali fusion, nitration, reduction, etc. For example, benzene is nitrated to nitrobenzene, and then reduced to aniline, which can be chemically processed into dyes, drugs, vulcanization accelerators, etc. Both 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 to butadiene, which can be chemically processed into synthetic rubber, synthetic fibers, and the like.
Butadiene is an intermediate.
It originally refers to the intermediate products produced in the process of synthesizing chemical products such as spices, dyes, resins, drugs, plasticizers, rubber accelerators, etc. using coal tar or petroleum products as raw materials. It now generally refers to various intermediate products obtained in the process of organic synthesis.
5-Bromo-2 4-dichloropyrimidine,4-Bromo-2-fluorobenzoic acid,4-Bromo-2-fluorobenzaldehyde,6-(4-Aminophenyl)-4 5-dihydro-5-methyl-3(2H)-pyridazinone Fuxin Custchem Fine Chemical Co., Ltd. , https://www.custchemvip.com
Miyinong (Chuzhou Agricultural Machinery Management Station) Gear-driven walking tractor A hand-held tractor that replaces the original chain transmission by gear transmission, and is put into the market by Dongfeng Agricultural Machinery Group Co., Ltd.
This kind of tractor was developed and developed by Changzhou Tractor Factory in the early 1980s. It replaced the original chain transmission box assembly with a full gear transmission assembly. According to the current requirements of hand-held tractors for farmland operations, requiring low power loss and high transmission efficiency, combined with the use of domestic tractors, after the improved design, the series of hand-pulls has been launched. This hand drag is a variant of the Dongfeng 12 series hand drag. Compared with the traditional hand drag, it has the following characteristics: First, the gear transmission is adopted, the transmission efficiency is high, and the performance is reliable; the second is interchangeable with the original chain transmission box; the third is the configurable gear pump, which is converted into a dump truck; Fourth, the speed has increased, the efficiency of farmland operations has improved; the fifth is the safety and service life have been improved. Therefore, the product has been welcomed by the majority of users after it has been put on the market.
(Small tow industry information network) Feeding the combine harvester has been greatly developed. Such small harvesters tend to reduce the amount of feed by increasing the cuttings, thereby reducing power consumption and reducing grain losses. However, the stubble after harvesting is too high, which is not conducive to the next season. Therefore, it is required to add a secondary cutter to the harvester for secondary cutting to reduce the cut after cutting. Generally, the lifting and lowering of the main and auxiliary cutters of the harvester need to be separately controlled, and the operation is very inconvenient, which may cause the main and auxiliary cutters to be uncoordinated and unbalanced, and cannot work normally.
The lifting device of the combine cutter sub-cutter introduced here, the lifting of the main and auxiliary cutters is controlled by the same operating handle, can realize the following linkage, when the main cutter is lowered, the harvester is in the harvest state, the secondary cutter Automatic floor floating, for the ground surface profile cutting When the main cutter is lifted, the secondary cutter automatically rises to the highest position when the harvester is in the transfer state, so that the harvester transfer (a) is a schematic front view of the lifting device structure. (b) is a side view.
The structural feature of the lifting device is that a fan-shaped ring gear 4 (both internal teeth and external teeth) which is the same center as the rotating shaft of the main cutter header 1 is fixed on the harvester chassis, and is mounted on the main cutting table bracket 5 The upper pinion 6 meshes. A pin that can be wound with a chain or a cord is mounted on the pinion shaft. 3. One end of the chain or cable 7 is fixed to the wheel 3, and the other end is connected to the hinge sliding groove 8 of the sub-cutter 2, and is cut by a tension spring 9 The slot plates 8 are connected.
The lifting device operates in such a manner that the center of the ring gear 4 fixed to the harvester chassis is at the same center as the center of rotation of the main header 1 and meshes with the pinion 6 connected to the main header 1. When the main header 1 ascends, the pinion 6 mounted on the main header holder 5 is rotated by the ring gear 4. The wheel 3 is rotated by the rotating shaft, and the chain or the cable 7 is driven to be wound in the groove of the wheel 3, so that the sub-cutter 2 is raised. When the main header 1 is raised to the highest point, the secondary cutter 2 reaches the apex at the same time. When the main header 1 is lowered to the normal harvesting position, the secondary cutter 2 is cut to the ground; when the primary header 1 is lowered again, the chain or the soft cord 7 starts. The rewinding sub-cutter 2 performs a profile cutting. When the ground suddenly lifts and the secondary cutter 2 floats upward, the chain or cable 7 slides within the sliding slot plate 8, and the tension spring 9 tensions the chain or the cable 7 so as not to relax.
The lifting device has a simple structure and is freely lifted and lowered. The main and auxiliary cutters are reasonably linked, and the main cutting knife is relatively sturdy (2535 cm), which reduces the feeding amount of the combine harvester and the sub-cutting knife to perform the surface cutting and cutting. The stubble (about 8cm) satisfies the requirements of agronomy for cutting. The lifting device has been granted a national patent (patent number ZL97230504.1) and has been applied to the Cangzhou-138 double cutter full feed combine harvester.