The lanthanum catalyst refers to an elemental lanthanum or lanthanum compound which has a catalytic function. Lanthanum is a silver-white rare earth metal that is soft and easy to cut and has ductility. Metal lanthanum is chemically active. Lanthanum is easily oxidized in the air, and its fresh surface quickly darkens when exposed to air. Lanthanum burns when heated to form oxides and nitrides. Lanthanum is heated in hydrogen to form a hydride, and when it’s reacting with hot water, hydrogen is evolved. The common valences of lanthanum have 0, +1, +2 and +3. The valence of ruthenium in most lanthanum catalysts is +3, such as lanthanum oxide, lanthanum chloride, and the like. In the earth's crust, lanthanum is present in monazite sand and bastnasite.
Figure 1. Lanthanum catalyst
Lanthanide not only enhances the activity of the reaction in organic synthesis, but also improves the selectivity of the reaction and has a special catalytic effect. Metal lanthanum, as one of the lanthanides, also has a good catalytic effect. In particular, some lanthanum compounds (such as lanthanum oxides and lanthanum salts) have a wide range of applications in organic synthesis. In addition, lanthanum catalysts have certain applications in environmental protection.
Figure 2. Lanthanum phosphotungstate catalyzed condensation reaction