The above materials are generally considered correct.
However, at present, the chemical community has not yet thoroughly studied the principles and functions of various catalysts. In other words, there is no complete understanding of how various catalysts work. The selection and application of catalysts rely more on experience.
So - I think this statement
"Is the essence of the catalyst in a chemical reaction to occur cyclic reactions and change the reaction rate? Generally speaking, in chemical reactions The catalyst does not participate in the reaction, and the quality and properties remain unchanged."
It is not precise enough, but it can be explained this way in some reactions, such as the reaction you mentioned.
As for the reaction of manganese dioxide with hydrogen peroxide, it can be understood that the interaction between manganese dioxide and hydrogen peroxide produces unstable and active intermediate products, which activates the reactant molecules and reduces the ability required for the reaction. , the activated molecules undergo further chemical reactions to produce oxygen and water. (If manganese dioxide is not used, we can also heat the reactant molecules to obtain enough energy to activate them and make them react)
Catalyst for producing hydrogen peroxide by anthraquinone method
Patent country: 62 Patent number: 01125029
Inventor: Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences
---------------- -------------------------------------------------- ---------------
The invention discloses a catalyst for producing hydrogen peroxide by anthraquinone method and its preparation method. The supported precious metal catalyst for hydrogenation of anthraquinone uses pre-treated sepiolite or sepiolite-Al↓[2]O↓[3] as a carrier and contains Pt0.2-0.4% by weight. Before use, sepiolite is soaked in acids of different concentrations at different solid-liquid ratios for a certain period of time, filtered, washed, dried, tableted, roasted, and crushed. The catalyst is prepared by impregnation method and has the characteristics of high activity and high selectivity. The catalyst of the present invention can achieve a hydrogenation efficiency of 8-12g (H↓[2]O↓[ 2〕)/l, the selectivity reaches over 97%.
The "Technology for Preparing High-Purity Azelaic Acid by Clean Catalytic Oxidation of Oleic Acid" project undertaken by the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, passed the achievement appraisal organized by the Gansu Provincial Department of Science and Technology and the Lanzhou Branch of the Chinese Academy of Sciences.
This research project uses oleic acid as raw material and uses hydrogen peroxide clean catalytic oxidation method to prepare azelaic acid. The kilogram-level product yield reaches 78, the purity is ≥99, and the quality reaches electronic grade.
This achievement replaces the more polluting nitric acid oxidant with a clean oxidant, realizing a green and clean production process without organic solvents; the selected phase transfer agent overcomes the difficulty of catalyst separation, serious loss, and solvent corrosion during the reaction process. and other shortcomings.
This project provides a technical foundation for pilot testing and industrialization for production fields with special requirements such as medicine, cosmetics, and electronic products, and has good economic and social benefits.
Article from: China Catalyst Network
Article author: webmaster
High-loading Ni catalyst for anthraquinone production of hydrogen peroxide
Study on High-Load Ni Catalyst for Production of Hydrogen Peroxide by Anthraquinone Method
Tan Jun Han Jiawang Liu Chunshan
Abstract: Taking the hydrogenation catalyst for the production of hydrogen peroxide by the anthraquinone method as the research object, The activity of the high-loading Ni hydrogenation catalyst using Al2O3 as the carrier under fixed bed reaction conditions was investigated, and the specific surface area, grain size, surface morphology, etc. of the hydrogenation catalyst under different preparation conditions were measured, and preliminary discussions were carried out. Intrinsic factors related to hydrogenation efficiency. The results show that in catalysts with Ni as the main active component, by selecting appropriate Ni loading and controlling catalyst preparation conditions such as reduction temperature and reduction time, δ, θ-Al2O3 can be fully utilized The physical and chemical properties of the carrier can produce a catalyst with a large specific surface area, highly dispersed active components, fine and irregular grains, and high hydrogenation activity.
Keywords: hydrogenation; nickel Catalyst; high dispersion; Al2O3; anthraquinone method; H2O2
Category number: TQ426.81 Document identification code: A
Article number: 1000-8144(2003)07-0555- 04
About the author: Tan Jun (1978-), female, from Chaling County, Hunan Province, master student, phone number 021-64253390, email tjjump@sina.com.
Author Unit: Tan Jun (East China University of Science and Technology, Shanghai, 200237)
Han Jiawang (East China University of Science and Technology, Shanghai, 200237)
Liu Chunshan (East China University of Science and Technology, Shanghai, 200237)
References:
〔1〕You Xiande.[J]. Chemical Commodity Science and Technology Information, 1996, 60～62.
〔2]Hu Changcheng.[J] . Liming Chemical, 1989, 19(3): 39～45.
〔3〕Solvay I. Direct Synthesis of Hydrogen Peroxide by Heterogeneous Catalysis, Catalyst for the Said Synthesis and Method of Preparation of the Said Catalyst [P]. US 5447706, 1995 -09- 05.
[4] You Xiande. [J]. Inorganic Salt Industry, 1997, 147(2): 14～16.
〔5〕Mitsubishi Gas Chem Co. Inc.. Production of Hydrogen Peroxide[P]. JP 08002904, 1996-01-09.
〔7〕Ishikawa Eiichi, Sugiyama Noboru.[J] .Journal of Industrial Chemistry (Japan), 1958, 61(4): 405～411.
〔8〕Santacesari E, et al. [J] .J Mol Catal, 1994, 145: 37～53 .
〔9〕Drelinkiewicz A. [J].J Mol Catal, 1995, 149: 61～69.
〔10] Ma Aizeng.[J]. Molecular Catalysis, 1999 , 13(5): 345～350.