Gadolinium Catalysts

The gadolinium catalyst refers to an elemental gadolinium or gadolinium compound which has a catalytic function. Gadolinium is a silver-white metal that is malleable and magnetic at room temperature. The melting and boiling points of gadolinium are very high. The content of gadolinium in the earth's crust is 0.000636%, mainly in monazite and bastnasite. The chemical nature of gadolinium is stable. Gadolinium does not react in dry air but loses its luster in wet air. Gadolinium can react slowly with water and dissolve in acid to form the corresponding salt. The common valence of gadolinium is +3. Gadolinium oxides and halides have a certain catalytic function and are often used as catalysts.

Figure 1. Gadolinium oxide catalyst

Applications:

The gadolinium catalyst is not only cheap, but also has high stability and good photodegradability, and is mainly used in environmental protection and organic synthesis.

• Organic synthesis: The imino Diels-Alder reaction of N-arylimine (heteroatom-containing diene) with nucleophilic olefin (dienophile) under the Lewis acid catalyst is one of the most effective methods for synthesizing tetrahydrowine skeleton. Gadolinium trichloride can be used as a catalyst for this reaction. The use of gadolinium trichloride not only enhances the activity, regioselectivity and stereoselectivity of the reaction, but also makes its conditions mild.

Figure 2. CdCl₃ catalyzes the imino Diels-Alder reaction

• Environmental protection: Catalytic ozone oxidation technology can decompose refractory organic macromolecular substances into non-toxic or slightly toxic inorganic matter by generating highly oxidizing free radicals (especially hydroxyl radicals) under alkaline conditions and then making them react with organic pollutants. The supported gadolinium trioxide has a significant promoting effect on the catalytic degradation of organic matter by ozone. The catalyst has good recovery and stability, causes no metal ion elution in the process of catalyzing ozone degradation of pollutants, and reduces the possibility of secondary pollution. It is a promising catalytic ozone oxidation catalyst. The catalytic mechanism is to generate more oxidizing substances such as hydroxyl radicals when ozone interacts with the solution to increase the removal rate of organic pollutants. Supported gadolinium oxide can be used to catalyze the degradation of levodopa in pharmaceutical waste water.

References

1. Zhou, Qin. (2013). "Oxidative dehydrogenation of ethane over RE-NiO (RE=La, Nd, Sm, Gd) catalysts." Journal of Rare Earths 31(7), 669-673.
2. Gryaznova, Z. V. (1977), "Hydrogenation of ethylene on gadolinium X,Y and L-type zeolites." Reaction Kinetics and Catalysis Letters 7(1), 59-64.
3. Eley, Daniel D. (1969), "Hydrogen isotope equilibration on gadolinium films." Zeitschrift fuer Physikalische Chemie (Muenchen, Germany) 64(1-4), 145-53.