Potassium Catalysts

Potassium is a silvery-white soft metal, waxy, can be cut with a knife, has a low melting point, a lower density than water, and is extremely chemically active (more active than sodium). It is one of the elements of theⅠA family and belongs to the alkali metal. Potassium has no elementary substance form in nature. But potassium is widely distributed in land and sea in the form of salts. It is also one of the important components in human muscle and nerve tissue.

Applications:

For the human body, potassium can regulate the proper osmotic pressure in the cells and the acid-base balance of the body fluids, and participate in the metabolism of sugars and proteins in cells. It is also an essential element of plant growth. In addition, potassium compounds sometimes play the role of catalysts in chemistry. Esterification reaction, transesterification, dehydrogenation reaction and syngas to produce low-carbon mixed alcohol reaction can be catalyzed by potassium compounds, resulting in milder reaction conditions and higher yields.

• Esterification reaction: The most common potassium compound catalyzed esterification reaction is the preparation of isopropyl chloroacetate. Isopropyl chloroacetate is a raw material for the production of new high-efficiency non-steroidal anti-inflammatory, antipyretic and analgesic naproxen and ibuprofen. It can be synthesized from chloroacetic acid and isopropanol under the catalysis of KHSO₄ (Figure 1). In addition, potassium compounds also catalyze the esterification of anhydrides with alcohols. The trade name of acetylsalicylic acid is aspirin, which inhibits platelet aggregation and is widely used in daily life. When a catalyst is used with a strong base KOH, the yield of the reaction is high and the reaction temperature is mild (Figure 2).

Figure 1. The reaction schematic of isopropyl chloroacetate.

Figure 2. The reaction schematic of acetylsalicylic acid.

• Transesterification: Dibutyl carbonate is an important organic synthesis intermediate with long carbon chains. The transesterification method mainly uses transesterification of dimethyl carbonate (DMC) with n-butanol (n-BuOH) to synthesize di-n-butyl carbonate. The dimethyl carbonate used in this method belongs to green chemicals and the reaction conditions are mild without contaminants. The catalyst for this reaction is K₂CO₃, KOH, CH₃ONa, and the like (Figure 3).

Figure 3. The schematic of transesterification.

• Dehydrogenation reaction: Catalytic dehydrogenation of low carbon alkanes to olefin is an important part of resource optimization. The addition of K₂O inhibits the side reactions of cracking reaction and aromatization reaction and increases the selectivity of isobutylene.
• Syngas to produce low carbon mixed alcohol reaction: Low-carbon alcohol is a high-octane, low-pollution automotive fuel additive that can be blended with gasoline to form an alcohol-oil hybrid fuel, or it can be used directly. Co-precipitated CNT-promoted Co-Mo-K sulfide-based catalysts were prepared using multi-walled carbon nanotubes (CNTs) as additives to significantly increase the hydrogenation activity of CO and the selectivity to lower alcohols.

References

1. Verkerk K A N , Jaeger B , Finkeldei C H , Keim W. Appl Catal A. 1999,186(1-2):407.
2. Li Zh R, Fu Y L , Bao J , Jiang M , Hu T D, Liu T , Xie Y N . Appl Catal A. 2001, 220(1-2):21.
3. Xinkui Wang, Shaoyi Peng. J. Natural Gas Chemistry. 1994, (3): 353.