Lithium Catalysts

Lithium (Li) is a silver-white metal that is soft and dense. Lithium reacts slowly with water at room temperature but reacts with nitrogen to form black monolithium nitride crystals. The weak acid salts of lithium are hardly soluble in water. In the alkali metal chloride, only lithium chloride is easily dissolved in an organic solvent. One of the earlier important uses of lithium compounds was in ceramic articles, particularly in enamel articles, where lithium compounds primarily acted as fluxing agents. In addition, lithium is easily combined with oxygen, nitrogen, sulfur, and etc., and it can be used as a deoxidizer in the metallurgical industry. Lithium can also be used as a lead-based alloy or a component of light alloys such as bismuth, magnesium and aluminum. The lithium amide obtained by the reaction of lithium and ammonia is used to introduce an amino group and is also used as a dehalogenating agent and a catalyst.

Applications:

• Catalytic polymerization reaction: Some researchers have used lithium siloxane as a catalyst to synthesize fluorosilicone rubber. As the amount of catalyst is reduced, the molecular weight of the fluorosilicone rubber will increase. Since the polymerization reaction catalyzed by the lithium alkoxide catalyst is not prone to depolymerization and is advantageous for the control of industrial production, it is easy to obtain a high molecular weight product.
• Catalytic isomerization reaction: Some researchers have used different methods to prepare a supported lithium phosphate catalyst for the isomerization of propylene oxide to allyl alcohol. Studies have shown that the specific surface area and pore structure of the catalyst obtained by the two methods of mixing and impregnation are different and have great influences on the catalytic performance of the catalyst. The catalyst obtained by the impregnation method has a larger specific surface area and better catalytic performance.
• Catalytic transesterification reaction: Some researchers have prepared lithium-doped TiO₂ catalyst by simple impregnation method and used it for the heterogeneous transesterification catalytic reaction of DMC and BPA. The structure and properties of the catalyst are greatly influenced by the amount of lithium-doping and the calcination temperature. When the calcination temperature is 400℃and the Ti/Li molar ratio is 6, the catalyst has excellent catalytic activity in the transesterification reaction of BPA and DMC.The by-product methanol after the reaction can be easily removed at low temperature.In addition, this catalyst exhibits excellent reusability. Therefore, the Li-doped TiO₂ catalyst can be used as a potential catalyst for the transesterification of DMC with BPA. The synthesis method with lithium sulfamate has the advantages of simple operation, short reaction time, high yield and environmental friendliness, and is an important supplement to the synthesis method of the existing oxyanthracene compounds.

Figure 1. Lithium catalyst catalyzes the reaction of BPA with DMC

• Catalytic other reactions: Some researchers have synthesized oxyanthracene compounds using lithium sulfamate catalysts without solvent, and also investigated the catalytic mechanism of lithium sulfamate. The synthesis method has the advantages of simple operation, short reaction time, high yield and environmental friendliness. It is an important supplement to the synthesis method of the existing oxyanthracene compounds.

Figure 2. Catalytic synthesis of oxyanthracene compounds by lithium sulfamate catalyst

Production:

At present, the methods for preparing a lithium catalyst mainly include mixing, dipping, microwave hydrothermal, ultrasonic synthesis, and the like method.

References

1. Ma Weihua, Lu Lude, Yang Xujie. (2005). "Characterization and reaction mechanism of propylene oxide isomerization products". Industrial Catalysis,12: 314-316.
2. Ma W, Si W. (2011)."Catalytic Properties of Lithium Phosphates". Catalysis. 141(7): 1032-1036.