Cerium containing nanoparticles prepared in non-polar solvent
View Patent ↗A method of making cerium-containing metal oxide nanoparticles in non-polar solvent eliminates the need for solvent shifting steps. The direct synthesis method involves: (a) forming a reaction mixture of a source of cerous ion and a carboxylic acid, and optionally, a hydrocarbon solvent; and optionally further comprises a non-cerous metal ion; (b) heating the reaction mixture to oxidize cerous ion to ceric ion; and (c) recovering a nanoparticle of either cerium oxide or a mixed metal oxide comprising cerium. The cerium-containing oxide nanoparticles thus obtained have cubic fluorite crystal structure and a geometric diameter in the range of about 1 nanometer to about 20 nanometers. Dispersions of cerium-containing oxide nanoparticles prepared by this method can be used as a component of a fuel or lubricant additive.
1. A method of making a cerium-containing metal oxide nanoparticle, comprising:
a) forming a reaction mixture of a source of cerous ion and a solvent, and optionally further comprising a non-cerous metal ion, wherein the solvent consists essentially of: (1) a carboxylic acid, wherein said carboxylic acid is a C 3 -C 22 paraffinic carboxylic acid, a monoether carboxylic acid, a polyether carboxylic acid, or a mixture thereof, and (2) an optional hydrocarbon; and
b) heating the reaction mixture to form a product dispersion containing cerium-containing metal oxide nanoparticles and less than about 0.5 wt. % water.
2. The method of claim 1 , wherein said cerium-containing metal oxide nanoparticle is of cubic fluorite crystal structure and has a geometric diameter of about 1 nanometer to about 20 nanometers.
3. The method of claim 1 , wherein said non-cerous metal ion is present in the reaction mixture, and said non-cerous metal ion is iron, zirconium, or a combination thereof.
4. The method of claim 1 , wherein said carboxylic acid is a C 3 -C 22 paraffinic carboxylic acid.
5. The method of claim 4 , wherein said paraffinic carboxylic acid is octanoic acid.
6. The method of claim 1 , wherein said carboxylic acid is a monoether carboxylic acid.
7. The method of claim 6 , wherein said monoether carboxylic acid is methoxyacetic acid.
8. The method of claim 1 , wherein said carboxylic acid is a polyether carboxylic acid.
9. The method of claim 8 , wherein said polyether carboxylic acid is 2-(2-methoxyethoxyl)acetic acid or 2-[2-(2-methoxyethoxy)ethoxy]acetic acid.
10. The method of claim 1 , wherein said hydrocarbon solvent is present in the reaction mixture, and said hydrocarbon solvent is a C 5 -C 25 paraffin, an olefin, an isoparaffin distillate, or a hydrotreated petroleum distillate.
11. The method of claim 10 , wherein said paraffin is a straight chain, a branched or a cyclic paraffin.
12. The method of claim 10 , wherein said olefin is 1-octadecene.
13. The method of claim 1 , wherein the reaction mixture is heated from about 100° C. to about 250° C.
14. A method of making cerium-containing metal oxide nanoparticles, comprising:
a) forming a reaction mixture comprising a source of cerous ion, an optional source of one or more non-cerous metal ions (M), and a solvent consisting essentially of a carboxylic acid and a hydrocarbon; and
b) heating the reaction mixture to oxidize cerous ion to ceric ion, thereby forming a product dispersion comprising cerium-containing metal oxide nanoparticles,
wherein the product dispersion comprises less than about 0.5 wt. % water.
15. The method of claim 14 , wherein said non-cerous metal ion is iron and/or zirconium.
16. The method of claim 14 , wherein said carboxylic acid is a C 3 -C 22 paraffinic or olefinic carboxylic acid.
17. The method of claim 14 , wherein said carboxylic acid is selected from the group consisting of: octanoic acid, oleic acid, methoxyacetic acid, 2-(2-methoxyethoxyl)acetic acid, 2-[2-(2-methoxyethoxyl)ethoxy]acetic acid, and mixtures thereof.
18. The method of claim 14 , wherein said hydrocarbon solvent is a C 5 -C 25 paraffin, an olefin, an isoparaffin distillate, or a hydrotreated petroleum distillate.
19. The method of claim 18 , wherein said olefin is 1-octadecene.
20. The method of claim 1 , wherein said cerium-containing metal oxide nanoparticles have a geometric diameter of less than about 2 nm.
21. The method of claim 14 , wherein said cerium-containing metal oxide nanoparticles have a geometric diameter of less than about 2 nm.