Method of preparing cerium dioxide nanoparticles

• US 9,993,803 B2
• Filed: 09/04/2007
• Issued: 06/12/2018
• Est. Priority Date: 09/05/2006
• Status: Active Grant

• Current Assignee: Cerion, LLC (Revstone Industries LLC)
• Original Assignee: Cerion, LLC (Revstone Industries LLC)
• Inventors: Difrancesco, Albert Gary, Hailstone, Richard K., Langner, Andreas, Reed, Kenneth J.
• Primary Examiner(s): McAvoy, Ellen M
• Assistant Examiner(s): Po, Ming Cheung
• Application Number:
  US12/440,165
• Publication Number:
  US 20110056123A1
• Time in Patent Office: 3,934 Days
• Field of Search: 44410, 44457
• CPC Class Codes: B01F 23/41 Emulsifying
• CPC Class Codes: B01F 27/812 the stirrers co-operating with surrounding stators, or with intermeshing stators, e.g. comprising slits, orifices or screens
• CPC Class Codes: B01J 13/0047 containing a metal oxide
• CPC Class Codes: B01J 13/0086 Preparation of sols by physical processes colloid mills B02C
• CPC Class Codes: B01J 23/10 of rare earths
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01F 17/235 Cerium oxides or hydroxides
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/52 highly monodisperse size distribution
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C10L 1/10 containing additives
• CPC Class Codes: C10L 1/103 stabilisation of anti-knock agents
• CPC Class Codes: C10L 1/1233 oxygen containing compounds, e.g. oxides, hydroxides, acids and salts thereof
• CPC Class Codes: C10L 1/125 water
• CPC Class Codes: C10L 1/1258 hydrogen peroxide, oxygenated water
• CPC Class Codes: C10L 1/1608 Well defined compounds, e.g. hexane, benzene
• CPC Class Codes: C10L 1/1616 fractions, e.g. lubricants, solvents, naphta, bitumen, tars, terpentine
• CPC Class Codes: C10L 1/1811 peroxides; ozonides
• CPC Class Codes: C10L 1/1824 mono-hydroxy
• CPC Class Codes: C10L 1/1881 : carboxylic group attached to an aliphatic carbon atom
• CPC Class Codes: C10L 1/1883 : polycarboxylic acid
• CPC Class Codes: C10L 1/19 : Esters ester radical containing compounds; ester ethers; carbonic acid esters C10L1/1802, C10L1/1805, C10L1/1808, C10L1/1811, C10L1/1814, C10L1/1817 take precedence
• CPC Class Codes: C10L 1/1985 : polyethers, e.g. di- polygylcols and derivatives; ethers - esters
• CPC Class Codes: C10L 1/2222 : (cyclo)aliphatic amines; polyamines (no macromolecular substituent 30C); quaternair ammonium compounds; carbamates C10L1/221 takes precedence
• CPC Class Codes: C10L 1/2437 : Sulfonic acids; Derivatives thereof, e.g. sulfonamides, sulfosuccinic acid esters
• CPC Class Codes: C10L 10/02 : for reducing smoke development
• CPC Class Codes: C10L 10/08 : for improving lubricity; for reducing wear
• CPC Class Codes: C10L 10/12 : for improving the cetane number
• CPC Class Codes: C10M 2201/062 : Oxides; Hydroxides; Carbonates or bicarbonates
• CPC Class Codes: C10N 2010/06 : Groups 3 or 13
• CPC Class Codes: C10N 2020/06 : Particles of special shape or size
• CPC Class Codes: C10N 2030/06 : Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2040/25 : Internal-combustion engines
• CPC Class Codes: Y02T 50/678 : Aviation using fuels of non-fossil origin

Abstract

A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.

Claims

1. A process for making cerium dioxide nanoparticles comprising the steps of:

providing an aqueous reaction mixture comprising a source of cerous ion, a source of hydroxide ion, a water soluble nanoparticle stabilizer comprising an alkoxylated carboxylic acid, or salt thereof, and an oxidant; and

providing temperature conditions effective to enable oxidation of cerous ion to ceric ion, wherein said temperature conditions effective to enable oxidation of cerous ion to ceric ion comprise a temperature less than 100°

C., thereby forming a product dispersion comprising cerium dioxide nanoparticles, wherein said nanoparticles are characterized by a crystalline cubic fluorite structure,

wherein said water soluble nanoparticle stabilizer comprises a compound of formula (Ia),

R—

O—

(CH₂CH₂O)_nCHR¹CO₂Y 

 

(Ia)

wherein;

R represents a methyl group or an ethyl group;

R¹ represents hydrogen or an alkyl group;

Y represents H or a counterion; and

n is 0-5.

2. The process according to claim 1, wherein R represents a methyl or ethyl group, R¹ represents hydrogen, and n is 1-2.

3. The process according to claim 2, wherein R represents a methyl group.

4. The process according to claim 1, wherein said water soluble nanoparticle stabilizer is 2-[2-(2-methoxyethoxy)ethoxy]acetic acid.

5. The process according to claim 1, wherein said source of cerous ion comprises cerous nitrate.

6. The process according to claim 1, wherein said temperature conditions effective to enable oxidation of cerous ion to ceric ion comprise a temperature from about 60°

C. to about 90°

C.

7. The process according to claim 1, wherein the pH of said reaction mixture is less than or equal to 7.

8. The process according to claim 1, wherein the pH of said reaction mixture is less than or equal to about 5.

9. The process according to claim 1, wherein said oxidant is hydrogen peroxide or molecular oxygen.

10. The process according to claim 1, further comprising the step:

mechanically shearing said reaction mixture and causing it to pass through a perforated screen.

11. A process for forming a homogeneous mixture containing cerium dioxide nanoparticles, at least water soluble one nanoparticle stabilizer, a surfactant, water, and a nonpolar solvent, said process comprising the steps of:

a) providing an aqueous mixture including stabilized cerium dioxide nanoparticles produced according to the process of claim 1;

b) concentrating said aqueous mixture including stabilized cerium dioxide nanoparticles to form an aqueous concentrate; and

c) combining said concentrate with said surfactant and said nonpolar solvent, thereby forming said homogeneous mixture,

wherein said water soluble nanoparticle stabilizer comprises a compound of formula (Ia),

R—

O—

(CH₂CH₂O)_nCHR¹CO₂Y 

 

(Ia)

wherein;

R represents a methyl group or an ethyl group;

R¹ represents hydrogen or an alkyl group;

Y represents H or a counterion; and

n is 0-5.

12. The process according to claim 11, wherein said water soluble nanoparticle stabilizer is 2-[2-(2-methoxyethoxy)ethoxy]acetic acid.

13. The process according to claim 11, wherein said surfactant comprises an anionic surfactant selected from a fatty acid, sodium bis(2-ethyl-1-hexyl)sulfosuccinate, or combinations thereof.

14. The process according to claim 11, wherein said concentrating said aqueous mixture is carried out using diafiltration to produce said aqueous concentrate.

15. The process according to claim 14, wherein said aqueous concentrate is characterized by a conductivity of about 5 mS/cm or less.

16. The process according to claim 11, further comprising the step of:

d) diluting one part of said homogeneous mixture with at least about 100 parts of a fuel.

17. The process according to claim 1, wherein said product dispersion comprises cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm.

18. The process according to claim 1, wherein n is 1 or 2.