What are the catalysts and what are the applications of the catalysts
Catalysts are chemicals commonly used in chemical experiments that can change the rate of chemical reaction of reactants without changing the chemical equilibrium. So what are the catalysts? What is the application of catalyst?
What are the catalysts
There are various types, and can be divided into liquid catalysts and solid catalysts according to the state. According to the state of the reaction system, it is divided into homogeneous catalyst and heterogeneous catalyst.
Heterogeneous phases include solid acid catalysis, organic bases, metals, metal oxides, composites, rare earths, molecular sieves, biological, nano, etc. According to the type of reaction, it is divided into catalysts such as polymerization, polycondensation, esterification, acetalization, hydrogenation, dehydrogenation, oxidation, reduction, alkylation, and isomerization. According to the size of the role, it is divided into main catalyst and auxiliary catalyst.
The reaction that is in the same stage as the reactants and there is no offset is called homogeneous catalysis, and the catalyst that can play the role of homogeneous catalysis is a homogeneous catalyst.
Homogeneous catalysts include liquid acids, base catalysts, Chromaticus solid acid and base catalysts, water-soluble overplating rate compounds (salts and compounds), and the like. Homogeneous catalysts act independently on molecules or ions, with uniform active centers and high activity and selectivity.
Heterogeneous catalysts, also known as heterogeneous catalysts, are in a different reaction, i.e. in a different state than the reactants they catalyze. For example, in the production of margarine, unsaturated vegetable oils and hydrogen can be converted into saturated fats by solid nickel (catalyst). Solid nickel is heterogeneous, and the reactants it catalyzes are liquid (vegetable oil) and gas.
Simple heterogeneous catalytic reactions include the adsorption of reactants on the surface of the catalyst, the cleavage of bonds in the reactants, and the generation of new bonds, but the bond between the product and the catalyst is not strong, so that the product deviates from the reaction site and other processes. As we all know, there are many other structures that adsorb and react on the surface of many catalysts.
Enzymes are biological catalysts, which are organic substances (most proteins) with catalytic ability produced by plants, animals and microorganisms. But small amounts of RNA also have biocatalytic functions.
The catalysis of enzymes is also selective. such as starch. Enzymes catalyze the hydrolysis of starch into gelatin and maltose, and proteases catalyze the hydrolysis of proteins into peptides, etc. Living organisms use them to speed up chemical reactions in the body. Without enzymes, many chemical reactions in organisms would be slow to sustain life.
At a temperature of about 37 (human body temperature), the enzyme works well. When the temperature exceeds 50 or 60, the enzymes are destroyed and can no longer function. Therefore, biodetergents that use enzymes to break down stains on clothes work well at low temperatures. Enzymes are of great significance in physiology, medicine, agriculture, and industry. At present, the application of enzyme preparations is more and more extensive.
It has important and extensive applications in chemical production. Catalysts should be used in the production of fertilizers, pesticides, various chemical raw materials and other products.
Catalysts exert their strengths in chemical industrial production, scientists' experiments, and life activities. For example, in the production of sulfuric acid, manganese dioxide pentoxide is used as a catalyst. The synthesis of ammonia from nitrogen and hydrogen is a multi-component catalyst mainly composed of iron, and it is necessary to improve the reaction rate.
Catalysts are even more indispensable for refineries, and gasoline and kerosene of different qualities can be obtained by using different catalysts. Chemical synthesis of acidic and basic Chromas catalysts. Car exhaust contains harmful carbon monoxide and nitric oxide, which can be quickly converted into harmless carbon dioxide and nitrogen if metals such as platinum are used as catalysts.
Enzymes are proteins with catalytic ability produced by plants, animals, and microorganisms. Almost all chemical reactions of organisms are carried out under the catalysis of enzymes. The brewing and pharmaceutical industries need catalysts to promote them.