There are three main homogeneous platinum catalysts: the first is to dissolve chloroplatinic acid (H2PtCl6▪6H2O) into ethanol, isopropyl alcohol and tetrahydrofuran and other organic solvents, so that they interact to form complexes, called "Speier catalyst", this catalyst is simple, quick and easy to use; The second type of platinum catalyst is the complex of platinum and vinyl double head, called Karstedt's catalyst, which has high reactivity, stable storage, and good compatibility with various types of polysiloxanes, and is the most widely used catalyst in the additive silicone release agent; The third type of platinum catalyst is chloroplatinic acid in addition to some other unsaturated compounds to form complexes, but also with ketones, cyclopentadienes, esters, alcohols, crown ethers, heteroatomic crown ethers and polysiloxanes to form complexes as catalysts.

Homogeneous platinum catalyst has high activity and reaction selectivity, but because it is in the same phase as the reactant, it is difficult to separate after the reaction and cannot be reused, so the cost is high, and it may bring heavy metal ion pollution. Therefore, researchers make heterogeneous catalysts by solidifying homogeneous catalysts. The so-called homogeneous catalyst is to combine the homogeneous catalyst with a solid carrier by physical or chemical methods to form a special catalyst. Heterogeneous platinum catalysts and reactants belong to different phases, and the common form of solid catalyst catalyzes the liquid mixed reactants to silane addition reaction.

Heterogeneous catalysts for hydrosilane addition can be divided into two types: traditional heterogeneous platinum catalyst and polymer metal complex catalyst. Among them, the traditional heterogeneous catalysts are formed by adsorbing transition metals on inorganic particles such as carbon black and alumina. Such catalysts have high stability and can be recycled, but their catalytic activity and selectivity are low, and the reaction process requires high temperature and pressure. Polymer metal complex catalyst consists of polymer carrier, ligand bonded to the carrier and transition metal. In general, although heterogeneous catalysts have the advantages of high stability and recycling, their application is limited due to their low activity and selectivity and complex preparation process, which reduces their catalytic activity when they are used again.

There are many substances that can make the platinum catalyst "toxic", causing its catalytic activity to decrease or even lose activity. For example, organic compounds containing nitrogen, phosphorus, sulfur and other elements and ionic compounds containing tin, lead, mercury, bismuth, arsenic and other heavy metals. Therefore, special attention needs to be paid to the use of platinum catalysts to avoid exposure to these substances that can make them toxic. There are many types and forms of platinum catalysts, so in the application process, the appropriate platinum catalyst should be selected according to the characteristics of the reaction system to achieve the best catalytic effect.

Platinum catalyst, plz check MY KP30