Due to the rapid growth of industry, catalytic reactions are becoming more and more popular in chemical production, engineering, metallurgy. Thanks to the use of catalysts, it is possible to turn low-grade raw materials into a valuable product.
Relevance
Catalytic reactions are distinguished by the variety of agents used. In organic synthesis, they contribute to a significant acceleration of dehydrogenation, hydrogenation, hydration, oxidation, polymerization. The catalyst can be considered a “philosophical stone”, which turns raw materials into finished products: fibers, drugs, chemicals, fertilizers, fuels, plastics.
Catalytic reactions make it possible to obtain numerous products, without which normal human life and activity are impossible.
Catalysis allows you to accelerate processes by thousands and millions of times, so it is currently used in 91% of various chemical industries.
Interesting Facts
Many modern industrial processes, for example, the synthesis of sulfuric acid, are feasible only with the use of a catalyst. A wide variety of catalytic agents provides the creation of motor oils for the automotive industry. In 1900, for the first time on an industrial scale, a catalytic synthesis of margarine from plant materials was carried out (by hydrogenation).
Since 1920, a mechanism for catalytic reactions to produce fibers and plastics has been developed. A significant event was the catalytic production of esters, olefins, carboxylic acids, as well as other starting materials for the manufacture of polymer compounds.
Oil refining
From the middle of the last century, catalytic reactions began to be used in oil refining. The processing of this valuable natural resource involves several catalytic processes:
reforming;
cracking;
hydrosulfonation;
polymerization;
hydrocracking;
alkylation.
Since the end of the last century, it has been possible to develop a catalytic converter that can reduce exhaust emissions into the atmosphere.
For work relating to catalysis and related fields, several Nobel Prizes were awarded.
Practical significance
A catalytic reaction is any process that involves the use of accelerators (catalysts). To assess the practical significance of such interactions, one can cite as an example the reactions associated with nitrogen and its compounds. Since in nature this amount is very limited, the creation of food protein without the use of synthetic ammonia is very problematic. The problem was solved with the development of the Gaber-Bosch catalytic process. The scope of use of catalysts is constantly expanding, which allows increasing the efficiency of many technologies.
Ammonia production
Consider some catalytic reactions. Examples from inorganic chemistry will be given on the basis of the most common industries. Ammonia synthesis is an exothermic, reversible reaction that is characterized by a decrease in the volume of a gaseous substance. The process proceeds on the catalyst, which is porous iron with the addition of aluminum oxide, calcium, potassium, silicon. Such a catalyst is active and stable in the temperature range 650-830K.
Its sulfur compounds, in particular carbon monoxide (CO), are irreversibly sent. Over the past few decades, thanks to the introduction of innovative technologies, it has been possible to significantly reduce pressure. For example, a converter was made that allowed to lower the pressure indicator to 8 * 106 - 15 * 106 Pa.
The modernization of the frontal circuit significantly reduced the likelihood of catalytic poisons in it - sulfur, chlorine compounds. The requirements for the catalyst have also increased significantly. If earlier it was produced by melting iron oxides (dross), adding oxides of magnesium and calcium, now cobalt oxide plays the role of a new activator.
Ammonia Oxidation
What are the characteristics of catalytic and non-catalytic reactions? Examples of processes whose course depends on the addition of certain substances can be considered based on the oxidation of ammonia :
4NH 3 + 5O 2 = 4NO + 6H 2 O.
This process is possible at a temperature of about 800 ° C, as well as a selective catalyst. To accelerate the interaction, platinum and its alloys with manganese, iron, chromium, cobalt are used. Currently, the main industrial catalyst is a mixture of platinum with rhodium and palladium. Such an approach allowed us to significantly reduce the cost of the process.
Water decomposition
Considering the equations of catalytic reactions, one cannot leave without due attention the reaction of obtaining gaseous oxygen and hydrogen by electrolysis of water. The process involves significant energy consumption, so on an industrial scale it is used infrequently.
Metallic platinum acts as an optimal accelerator for such a process with particle sizes of the order of 5-10 nm (nanoclusters). The introduction of such a substance accelerates the decomposition of water by 20-30 percent. Among the advantages, one can also note the stability of the platinum catalyst with carbon monoxide.
In 2010, a team of American scientists received a cheap catalyst, which allows to reduce energy costs for electrolysis of water. It was a combination of nickel and boron, the cost of which is significantly lower than platinum. Boron-nickel catalyst has been appreciated in the production of industrial hydrogen.
Synthesis of Aluminum Iodide
This salt is obtained by reacting an aluminum powder with iodine. Just one drop of water playing the role of a catalyst is enough to start a chemical interaction.
First, the role of the process accelerator is played by an aluminum oxide film. Iodine, dissolving in water, forms a mixture of hydroiodic and iodine acids. Acid, in turn, dissolves the aluminum oxide film, acting as a catalyst in the chemical process.
To summarize
The scale of application of catalytic processes in various areas of modern industry is increasing every year. Catalysts are needed that can neutralize substances hazardous to the environment. The role of compounds necessary for the manufacture of synthetic hydrocarbons from coal and gas is also growing. New technologies help reduce energy costs in industrial production of a variety of substances.
Thanks to catalysis, it is possible to obtain polymer compounds, products with valuable properties, to modernize the technology of converting fuel into electrical energy, to synthesize substances necessary for human life and activity.