Complete collection of detailed information about catalytic reactions

A chemical reaction under the action of a catalyst is called a catalytic reaction. In chemical reactions, some of the original chemical bonds of reaction molecules must be dissociated to form new chemical bonds, which requires a certain activation energy. In some systems where chemical reactions are difficult to occur, adding a third substance (catalyst) which is helpful to the rearrangement of chemical bonds of the reaction molecules can reduce the activation energy of the reaction, thus accelerating the chemical reaction and controlling the selectivity and stereoregularity of the products.

Basic introduction Chinese name: catalytic reaction mbth: the essence of catalytic reaction: the necessary condition of chemical reaction under the action of catalyst: the catalytic reason of catalytic action: the limitation of reaction activation energy: the characteristics of catalytic reaction such as accelerated chemical reaction and controllable products, etc. Introduction of catalyst, catalytic action, classification of catalytic reaction, danger and safety, catalytic reaction equipment and catalytic reaction characteristics A catalyst can only selectively accelerate a specific reaction, which may make the chemical reaction move in one of several thermodynamic possible directions. When the catalyst and reactant are in the same phase, it is called homogeneous catalytic reaction, and when they are in different phases, it is called heterogeneous catalytic reaction. The reaction involving biocatalyst-enzyme is called enzyme-catalyzed reaction. Most industrial reactions are catalytic reactions. Metabolism, nutrition and energy conversion in organisms are all reaction processes catalyzed by enzymes. Compared with the uncatalyzed reaction, the activation energy of catalytic reaction is lower at the same temperature. Catalysts can achieve polarization effect by combining reactants, such as acidic catalysts for synthesizing carbonyl compounds; The catalyst can also produce unnatural reaction intermediates, such as osmium salt ester produced in the dihydroxylation of olefins catalyzed by osmium tetroxide; Catalysts can also cause cracking of reactants, such as monoatomic hydrogen produced during hydrogen production. A substance that can change the reaction speed in a chemical reaction while its composition and quality remain unchanged before and after the reaction is called a catalyst. What can accelerate the reaction is called a positive catalyst; Those substances that can slow down the reaction rate are called negative catalysts or moderators. Usually, the catalyst is a calibration catalyst. Commonly used catalysts mainly include metals, metal oxides and inorganic acids. Catalysts are usually selective and can change the speed of a certain reaction or a certain type of reaction. In addition, some chemical reactions will produce different products due to different reaction conditions (including different catalysts). Catalytic reaction is a chemical reaction under the action of catalyst. For example, sulfur dioxide and oxygen synthesize sulfur trioxide under the action of catalyst, and nitrogen and hydrogen synthesize ammonia under the action of catalyst, all of which are catalytic reactions. Catalyst is a chemical substance that can change the reaction speed of chemical reaction without changing the thermodynamic equilibrium position of chemical reaction, and there is no obvious consumption in chemical reaction. ① Accelerate the chemical reaction rate and improve the production capacity; (2) For complex reactions, the rate of main reaction can be selectively accelerated, side reactions can be suppressed, and the yield of target products can be improved; ③ Improve operating conditions, reduce equipment requirements and improve production conditions; (4) Developing new reaction technology, expanding the utilization of raw materials and simplifying the production process; ⑤ Eliminate pollution and protect the environment. The classification of catalytic reactions can be classified according to the reaction mechanism, which can be divided into acid-base catalytic reactions and redox catalytic reactions. According to the reaction type, it can be divided into hydrogenation, dehydrogenation, oxidation, carbonylation, polymerization, halogenation, cracking, hydration, alkylation and isomerization. Hazardous and safe catalytic reactions can be divided into single-phase reactions and heterogeneous reactions. Single-phase reaction is carried out in gaseous or liquid state, and the conditions such as temperature and pressure in the reaction process are easy to adjust, so the danger is less. In heterogeneous reactions, catalysis occurs at the phase interface and the catalyst surface. It is difficult to control the temperature and pressure at this time, which is more dangerous. In the catalytic reaction, the catalyst should be selected correctly, the amount of catalyst should be appropriate, the heat dissipation should be ensured, the local reaction should be prevented from being fierce, and the temperature should be strictly controlled. If the catalytic reaction process can be carried out continuously, the danger can be reduced by adopting an automatic temperature regulation system. In the catalytic reaction, when the impurities in the feed gas react with the catalyst, explosion may occur, which is very dangerous. For example, in the reaction of synthesizing acetaldehyde by catalytic oxidation of ethylene, because there are a large number of cuprous salts in the catalyst system, if the feed gas contains too much acetylene, acetylene reacts with cuprous to generate copper acetylene, which is a red precipitate, and its spontaneous combustion point is 260~270℃, which is easy to explode in dry state and easily oxidized and burned under the action of air. Hydrocarbons react with metal salts in the catalyst to form insoluble lumps, which not only changes the composition of the catalyst. And the handle is easy to cause explosion. In the process of catalytic reaction, some produce hydrogen chloride, which is in danger of corrosion and poisoning; Some produce hydrogen sulfide, and the risk of poisoning is greater. In addition, the explosion limit of hydrogen sulfide in air is wide, and there is explosion danger in the production process. In the catalytic reaction of hydrogen production, there is a great explosion danger, especially under high pressure, the corrosion of hydrogen makes the metal high-pressure container brittle, thus causing destructive accidents. X-Cube is a desktop continuous flow chemical reaction system, which is suitable for efficient, rapid and safe catalyst screening, gas addition reaction and condition optimization reaction screening. X-Cube uses the award-winning product H-cube &; Reg's excellent technology, after effectively mixing the reaction substrate and gas reactant, can carry out continuous flow reaction under the reaction conditions as high as 200℃ and 150bar. X-Cube with efficient microfluidic reaction technology is an ideal reaction optimization and catalyst screening instrument for chemists who study catalysts and chemical reactions in the fields of medicine, fine chemicals, chemistry and petrochemical industry. Combined with CatCart Changer six-channel catalyst filter developed by Thalesnano, X-Cube can simultaneously screen six different catalysts in parallel.