Catalyst and Auxiliary

Catalyst refers to a substance that can change the rate of chemical reaction but does not consume in the reaction itself. It can also act on plants and change the growth rate of plants. According to the definition of the International Union of Pure and Applied Chemistry in 1981：Catalyst is a substance that changes the reaction rate but does not change the Gibbs free energy of the general standard of reaction. It is a very stable substance, its own composition, chemical properties and quality will not change before and after the reaction, and its relationship with the reaction system is like a lock and a key, with a high degree of selectivity, also known as specificity. It is mainly reflected in: 1. A catalyst does not catalyze all chemical reactions   2.Some chemical reactions are not the only catalyst   3.A chemical reaction has more than one catalyst.
There are many kinds of catalysts, which can be divided into liquid catalyst and solid catalyst according to the state, main catalyst and co-catalyst according to the size of the action, polymerization, Polycondensation, oxidation, reduction and other catalysts according to the type of reaction. According to the phase state of the reaction system, it can be divided into homogeneous catalyst and heterogeneous catalyst, in which the homogeneous catalyst is acid, alkali, soluble transition metal compound and peroxide catalyst, and the heterogeneous catalyst is metal catalyst, biocatalyst, nanometer catalyst and so on.
And catalysts are widely used and play an important role in chemical production, scientists' experiments and life activities. Some industrial production, such as winemaking and pharmaceuticals, also require catalysts. So the development power of the catalyst is still considerable.


In medicine, auxiliaries are defined as excipients and additives used in the production and formulation of drugs, that is, the general name of all materials except the main active components of drugs, and is an important part of pharmaceutical preparations. In industrial production, auxiliary chemicals added to improve the production process, to improve product quality and output, or to give the product a unique application performance. Also known as additives. However, as an important component of the product matrix, high-dose supplements, which have a significant impact on the morphology, structure and properties of the product, generally do not fall into the category of auxiliaries. According to the function and function of auxiliaries, they can be divided into five categories: synthetic auxiliaries, cross-linking auxiliaries, functional auxiliaries, stability auxiliaries and process auxiliaries.
The auxiliaries should have good compatibility with the synthetic resin added, and can be stable and uniformly dispersed in the resin for a long time. When in use, plastic auxiliaries that can promote the function of each other should be selected as far as possible. to be able to use the requirements of the use of products, to be able to have good adaptability to processing conditions, to be able to disperse uniformly in the process of processing and molding, and must be durable and non-volatile. When using, we should also pay attention to the dosage of auxiliaries.
Most of the auxiliaries are dangerous chemicals, some are flammable and explosive, and some are toxic. The new technology has continuously improved the performance requirements of auxiliaries, which has promoted the rapid development of the auxiliaries industry, and is bound to enter a new era of technological innovation, increase in varieties, advanced performance and friendly environment. High efficiency, functionalization, compounding, refinement, specialization, serialization, energy saving and environmental protection have become the general trend of the development of modern adhesive additives.
Auxiliaries can also be divided into auxiliaries to improve processing properties, such as lubricants, stabilizers, processing aids, etc.; change mechanical properties, such as plasticizers, toughening agents, etc.; improve optical properties, such as pigments, dyes, etc.; improve aging properties, such as antioxidants, anti-mildew agents, etc.; improve surface properties, such as antistatic agents, wear resistant agents, etc.; reduce costs, such as diluents, solvents, fillers, etc. Improve other properties, such as foaming agent, combustion promoter, etc.