In industry, the production of caprolactam from benzene is considered the most promising method. Let us consider in more detail the features of this production, as well as the main characteristics of the resulting compound.
Synthesis Features
In the technological chain there is hydrogenation of benzene to cycloalkane (with a platinum or nickel-chromium catalyst, temperature 220 ° C). The cyclohexane formed during oxidation is converted to cyclohexanone at 0.9-1.1 MPa, 140-160 ° C. Then, by dehydrogenation on chromium-zinc catalysts (in the presence of alkali), it is converted to oxime. At the last stage, cyclohexanone oxime is treated with oleum or concentrated sulfuric acid, turning it into caprolactam (the synthesis temperature is 60-120 ° C).
Process features
What percentage of caprolactam is obtained in the described manner? In fact, the product yield is 66-68 percent. That is why other production technologies have been developed. In particular, photochemical synthesis, in which 86-88% is obtained by photochemical nitrosation of cyclohexane into caprolactam under the influence of UV radiation.
In the chemical industry, caprolactam is also produced from toluene, oxidizing it at 165 ° C (on a platinum catalyst), followed by nitrosation of the resulting cyclohexane carboxylic acid into raw caprolactam.
What is caprolactam obtained by one of the methods listed above? In fact, it is a solid substance in which there are impurities. First, it must be cleaned of them using ion-exchange resins, then distilled. A by-product of this production is ammonium sulfate, a valuable mineral fertilizer.
Solid caprolactam is transported in paper multilayer bags, and the liquid product is transported in special tanks with additional heating. Currently, this component is obtained mainly from benzene, phenol, toluene.
Basic properties
What is the difference between caprolactam? The properties of this heterocyclic compound deserve separate consideration. It is a white crystalline substance having good solubility in water, ether, alcohol, benzene. Heating it in the presence of amines, alcohol and water leads to the polymerization of caprolactam into a polyamide resin. It is this substance that is the basis for the manufacture of the polymer. So, the monomer for the process is precisely caprolactam. What is polymerization? By this term is meant the process of obtaining from a monomer a product - capron.
Areas of use
What is the main purpose of the production in question? Why in the chemical industry get caprolactam? Its application is quite diverse. It is necessary for polyamide films, engineering plates. In minimal volumes it is used in the synthesis of lysine and polyurethane. Why is caprolactam so popular? What it is? This organic compound is used in the synthesis of solvents for paints, as well as in the creation of synthetic leather, plasticizers.
Consumption by industry
In which particular industries is caprolactam needed? What is it - kapron? These issues are considered in the framework of the school course in organic chemistry. There is a demand for these products in the automotive industry. But despite this, its maximum volumes go to the manufacture of polyamide fibers and threads, as well as to the manufacture of modern engineering plastics (about 60% - to fibers and threads, about 34% - to the manufacture of engineering plastics). The remaining raw materials are used in the creation of packaging materials, various products for the plumbing industry.
Polyamide fibers are needed for the manufacture of textiles, industrial threads, carpet products. It is this product that is becoming increasingly popular in the market of polymer materials.
Important points
In the manufacture of structural plastics, Pub resin is also in demand. It is a component for the production of elements of electrical and electronic equipment, as well as automotive parts. Oriented polyamide film is a material that is widely used in the packaging industry. In its manufacture, caprolactam is also used.
What is lysine? Let us dwell on this substance in more detail. Lysine is an amino acid that a person needs for the normal functioning of the body. The lack of this substance leads to a violation of the human immune system, which negatively affects the health of the body as a whole. Chemical synthesis of lysine from caprolactam through several successive stages is a technology that allows you to solve the problem of the deficiency of this substance. The use of innovative technologies makes it possible to speed up the process, reduce its cost.
To summarize
Among the products that can be obtained from caprolactam, polyamide fibers and resins are of particular interest. In particular, kapron has also received the maximum prevalence. This polymer is indispensable in many industrial fields. It is used in mechanical engineering, surgical medicine, chemical production, instrument making. It is from kapron that high-quality slings for modern parachutes, ropes, ropes, various fishing tackle, strings for musical instruments, clothes, toys are made.
A huge amount of polymer materials obtained from caprolactam explain the demand for this material in the world market. So, the strength of kapron threads is ten times greater than that of silk, 50 times higher than viscose. For the production of polymers only high-quality raw materials are used.
That is why special attention in the modern chemical industry is paid to the preliminary purification of caprolactam from additional impurities (dust, moisture). Otherwise, it is difficult to count on obtaining a capron of the desired quality.
Over the past decade, the production of plastics and synthetic resins has increased significantly. New materials are created based on caprolactam. The demand for these compounds in mechanical engineering and construction is also growing.