The process of the catalyst carrier
to achieve the catalytic effect
A specific catalyst carrier
can only be effective for a specific chemical reaction, which is often referred to as the "selectivity" of the catalyst. Of course, this choice is also a "two-way choice." This means that there is no catalyst that can catalyze all chemical reactions. Under normal circumstances, a certain catalyst can only catalyze a specific chemical reaction or a certain type of chemical reaction. At the same time, there is no chemical reaction, and all catalysts can catalyze it. Under normal circumstances, there are not many substances that can catalyze a chemical reaction, and there are differences in catalytic efficiency.
In chemical production, there is often such a situation that raw materials may undergo multiple chemical reactions and produce multiple products under reaction conditions. Generally, there is only one reaction that people want to occur (often called the main reaction), and the product (often called the main reaction) Called the main product) is what people need to obtain; and other reactions, people do not want them to occur, because these reactions not only waste the raw materials, but also the reaction product is mixed in the main product, reducing the purity of the product. In chemical production, these reactions that accompany the main reaction are often called side reactions, and the products of the side reactions are called by-products. How to reduce the occurrence of side reactions and reduce the amount of by-products is a problem that must be considered in almost every chemical production reaction. In this regard, the "selectivity" of the catalyst plays an important role. Therefore, in chemical production, scientists often take advantage of the selectivity of the catalyst to the reaction, use a specific catalyst, "select" the main reaction and reject other side reactions, so that the main reaction is accelerated, so as to obtain more main products and reduce other side reactions. Side reactions and by-products.
The catalyst can exert its best effect only under certain conditions. For example, the iron catalyst used in the synthesis of ammonia has an optimal working temperature of about 500°C. At this temperature, its catalytic ability is the strongest. Based on this, the temperature of synthetic ammonia in industry is usually controlled at about 500°C. Of course, the optimal temperature required for different catalysts is not the same. The iron catalyst for ammonia synthesis needs to be used at about 500°C, and some catalysts may be deactivated early due to high temperature at 500°C. Therefore, the most suitable reaction conditions should be selected according to the nature of the catalyst, instead of "drawing a gourd according to the pattern."
Industrial catalysts usually require certain supports and co-catalysts. The same is true for catalysts. For an industrial catalyst to achieve excellent catalytic performance, active substances are not enough. Under normal circumstances, in addition to the catalytically active substances that play a core role, industrial catalysts may also contain carriers and co-catalysts. In order to better achieve the catalytic effect of the catalyst, in addition to the active material, scientists add another one or several substances to the catalyst to enhance the catalytic effect of the catalyst. The added material is called a co-catalyst.