How should catalysts be accurately classified
What is the catalyst?
According to the 1981 definition of the International Union of Pure and Applied Chemistry (IUPAC): a catalyst is a substance that changes the reaction rate but does not change the overall standard Gibbs free energy of the reaction. .
Catalyst was first discovered by the Swedish chemist Berzelius as early as 1836. A paper published in the journal “Annals of Physics and Chemistry” proposed for the first time the concepts of “catalysis” and “catalyst” used in chemical reactions.
The role of catalysts in chemical reactions is called catalysis. Solid catalysts are also called catalysts in industry.
How are catalysts classified?
A wide range of catalysts:
——According to state, it can be divided into liquid catalyst and solid catalyst.
——According to the phase state of the reaction system, it is divided into homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts include acids, bases, soluble transition metal compounds and peroxide catalysts; Heterogeneous catalysts include solid acid catalysts, organic base catalysts, metal catalysts, metal oxide catalysts, complex catalysts, rare earth catalysts, molecular sieve catalysts, biocatalysts, nanocatalysts, etc.
——According to the reaction type, it is divided into polymerization, polycondensation, esterification, acetalization, hydrogenation, dehydrogenation, oxidation, reduction, alkylation, and isomerization and other catalysts.
——According to the size of the effect, it is also divided into main catalyst and co-catalyst.
What are the uses of catalysts?
Catalysts are important and widely used in chemical production. Catalysts are used in the production of fertilizers, pesticides, and various chemical raw materials.
Catalysts are widely used in all walks of life around the world. In the future, whether in the scientific theoretical research of catalysts, the development and utilization of clean energy, environmental protection and improvement of economic benefits, and the management of the human living environment and protection have great prospects for development. In short, the survival and development of human beings, food, clothing, shelter and transportation are inseparable from catalysts and their development.
What are the classification rules for catalysts?
Mainly divided into the following two categories:
(1) It is mainly composed of one or several active substances deposited on a carrier (called a “carrier catalyst”) or a mixture with active substances as the base material. In most cases, these active materials are certain metals, metal oxides, other metal compounds, and mixtures thereof. Metals often used alone or in the form of compounds are cobalt, nickel, palladium, platinum, molybdenum, chromium, copper or zinc. The carrier (which can sometimes be activated) is usually composed of alumina, carbon, silica gel, silica powder or ceramic materials. Supported catalysts include Ziegler catalysts and Ziegler-Natta catalysts.
(2) It is a mixture with certain compounds as basic components. The properties and proportions of these compounds vary according to different catalytic chemical reactions. These preparations include:
Free radical “catalysts” (e.g., organic peroxides or organic solutions of azo compounds, redox mixtures);
Ionic “catalysts” (e.g., alkyllithium catalysts);
“Condensation polymerization catalyst” (for example, a mixture of calcium acetate and antimony trioxide).
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®More products
ZF-10: high-efficiency and low-odor foaming catalyst, typically used in the preparation of low-odor polyurethane foam products
ZR-50: low-odor gel catalyst, providing excellent balance and can be used for polyurethane molded high-resilience foam
Z-131: Reactive low-odor gel amine catalyst compound
Z-130: low odor gel catalyst, balanced gel/foaming
ZR-70: Low odor catalyst for packaging foam and molded foam on vinyl skins Good balance of foaming and gelling
ZR-40 (pentamethyldipropylenediamine): Particularly effective for cold molded high-resilience foam, with a good balance between low-odor gel and foaming Catalyst
LE-310: low-odor reactive gel catalyst applied to large sponges, new low-VOC amine gel catalyst, amine content exceeds 95%
LE-530: Reactive gel catalyst, used in various polyurethane foam products
DPA: low-odor gel catalyst, outstanding balance and versatility provide good fluidity
TAP 1-methyl-4-(2-dimethylaminoethyl)piperazine: excellent trimerization catalyst that improves fluidity
DMDEE (2,2′-Dimorpholine diethyl ether): Strong foaming catalyst, providing stability Prepolymer system
DMAEE: low-density full-water rigid foam and low-density semi-rigid foam
BDMAEE bis-(2-dimethylaminoethyl) ether: efficient foaming catalyst
BDMA (N,N-dimethylbenzylamine): polyurethane rigid foam catalyst, epoxy accelerator
DMEA (N,N’-dimethylethanolamine): Neutralizes acid in some rigid foam systems,
PMDETA (pentamethyldiethylenetriamine): Particularly effective for HCFC/water foamed hard foam, similar to PC5
