A substance containing gold and having a catalytic function is called a gold catalyst. Gold is a transition metal and is located in Group IB of the sixth period. Gold usually appears in its form as an elementary substance in nature. Gold is chemically inert and does not chemically react with most chemicals. It does not react with oxygen at normal temperature, and only the heating and other processes can produce gold oxide. Gold compounds can form trivalent and monovalent gold ions after dissolving in solution. The valence of gold in common gold catalysts is +1 or +3.
Figure 1. Gold catalyst catalyzed Suzuki reaction
Because of their rich varieties, good catalytic performance and environmental protection, gold catalysts are widely used in organic synthesis and environmental protection.
Oxidation reaction: The propylene oxide has many important uses in the industry. At present, the production of propylene oxide by the chlorohydrin method is industrially used, but the method has environmental problems. The supported nano-gold catalyst is a green catalyst which can be used for the catalytic oxidation of olefins. In the catalytic process, the catalyst activity is inversely proportional to the nanogold particle size, and the reaction selectivity is very high. Alcohol selective oxidation is an important route for the synthesis of carbonyl compounds or related derivatives, and these carbonyl compounds or carbonyl derivatives are often used as intermediates for pharmaceuticals or pesticides. Nanogold can also be used as a gold catalyst to catalyze the selective oxidation of alcohols. For example, the oxidation of an alcohol to an aldehyde can be catalyzed by a nano-gold catalyst prepared by using a Cu-Mg-Al ternary composite oxide as a support. The nano-gold catalyst can also catalyze the oxidation of the aldehyde to form the corresponding carboxylic acid. The use of a nano-gold catalyst to catalyze the oxidation of an aldehyde has the advantages of a wide solvent system, good catalytic performance, and high yield.
Figure 2. Gold catalyst catalyzed C-H activation reaction