Views: 0 Author: Site Editor Publish Time: 2021-04-26 Origin: Site
In fact, the use of intermediates is a variety of development, a certain kind of intermediate used in dyes called dye intermediates, and used in pesticides, medicine is also called pesticide, pharmaceutical intermediates. Intermediates should be considered as a whole branch of the fine chemical industry, and should not be categorized into dye intermediates, pesticide intermediates and pharmaceutical intermediates according to the industry, which will reduce the range of use of some intermediates and affect their development.
The research on fine chemical intermediates is characterized by a wide variety. Except for a few varieties, which have a very large production scale, most varieties are not very large in tonnage. However, the preparation process is often complex, involving many unit reactions and separation processes, and a considerable amount of "three wastes" are generated in the production which need to be properly treated. Therefore, it is necessary to study the process of serialized products and organize the production of intermediates reasonably to obtain good economies of scale.
From the situation of foreign countries, the research and production of intermediates tend to properly concentrate to achieve serial production, a set of production equipment can produce several to a dozen varieties of intermediates, such research and production through the overall development, the implementation of new technology is relatively easy, will achieve twice the result with half the effort. The situation in Japan can provide us with reference. The production of intermediates in Japan was also very dispersed. Since the 1960s, it has been adjusted and centralized for seven times.
Through transformation and development, China's dyeing and pigment intermediate industry has reached a higher level in terms of production scale, technology and equipment level, which can not only meet the needs of domestic dyeing and pigment industry development, but also provide more high-quality intermediate products for foreign countries.
The raw materials needed for the synthesis of intermediates are mainly obtained from petroleum and coking chemical industry products, most of which are benzene series, naphthalene series, anthraquinone series compounds, as well as some heterocyclic compounds. In recent years, organic pigments prepared by heterocyclic compounds intermediates show an increasing trend. In addition, phenanthrene, pyridine, oxyfluorene, quinoline, indole, carbazole, biphenyl series compounds, these complex raw materials are applied to the manufacture of dyes, then the use of synthetic raw materials will be more extensive and universal.