Aggregates of ceric oxide crystallites and reduction of vehicular emissions therewith

• US 6,093,223 A
• Filed: 11/04/1996
• Issued: 07/25/2000
• Est. Priority Date: 11/25/1992
• Status: Expired due to Term

• Current Assignee: Rhone-Poulenc Chimie
• Original Assignee: Rhone-Poulenc Chimie
• Inventors: Lemaire, Jacques, Touret, Olivier, Petta, Denis
• Primary Examiner(s): Johnson, Jerry D.
• Application Number:
  US08/741,792
• Time in Patent Office: 1,359 Days
• Field of Search: 44/354, 44/363, 44/358, 44/500
• US Class Current: 44/354
• CPC Class Codes: B01J 23/10 of rare earths
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• 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 2002/60 Compounds characterised by their crystallite size
• CPC Class Codes: C01P 2004/10 extending in one dimension, e.g. needle-like
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• 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 1/1233 oxygen containing compounds, e.g. oxides, hydroxides, acids and salts thereof
• CPC Class Codes: C10L 1/1616 fractions, e.g. lubricants, solvents, naphta, bitumen, tars, terpentine
• CPC Class Codes: C10L 1/1881 carboxylic group attached to an aliphatic carbon atom
• CPC Class Codes: C10L 10/06 for facilitating soot removal
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02

Abstract

Vehicular emissions are reduced/purified via combustion of the hydrocarbon fuel therefor, e.g., diesel fuel, in the presence of a cerium compound, preferably a cerium (IV) compound, to produce soots having depressed ignition temperatures that contain effective purifying amounts of aggregates of ceric oxide crystallites, the largest particle size dimension of which ranging from 50 Å (5 nanometers) to 10,000 Å (1,000 nanometers) and the crystallite sizes of which, measured by Debye-Scherrer technique, ranging from 50 Å (5 nanometers) to 250 Å (25 nanometers).

Claims

1. A hydrocarbon fuel soot produced by combustion of diesel fuel, the soot containing at least 0.1% by weight of aggregates consisting essentially of ceric oxide crystallites, the largest particle size dimension of which ranging from 50 Å

to 10,000 Å and

the crystallite sizes of which, measured by Debye-Scherrer technique, ranging from 50 Å

to 250 Å

, wherein the soot exhibits an ignition temperature of less than 400°

C.

2. The hydrocarbon fuel soot containing aggregates of ceric oxide crystallites as defined by claim 1, said largest particle size dimension ranging from 100 Å

to 5,000 Å and

said crystallite sizes ranging from 100 Å

to 200 Å

.

3. The hydrocarbon fuel soot containing aggregates of ceric oxide crystallites as defined by claim 1, the aggregates having a particle size distribution characterized by d₂₀ and d₈₀, d₂₀ being a particle size at which 20% of the aggregates are smaller and d₈₀ being a particle size at which 80% of the aggregates are smaller, the d₈₀ of the aggregates being at most 10,000 Å

and the d₂₀ of the aggregates being greater than 200 Å

.

4. The hydrocarbon fuel soot containing aggregates of ceric oxide crystallites as defined by claim 1, the crystallites having a particle size distribution characterized by d₂₀ and d₈₀, d₂₀ being a particle size at which 20% of the crystallites are smaller and d₈₀ being a particle size at which 80% of the crystallites are smaller, the d₈₀ of the crystallites being at most 5000 Å

and the d₂₀ of the crystallites being greater than 500 Å

.

5. A process for the production of the aggregates of ceric oxide crystallites as defined by claim 1, comprising burning a hydrocarbon fuel in the presence of a seed amount of said aggregates of said ceric oxide crystallites.

6. A hydrocarbon fuel soot produced by combustion of diesel fuel, the soot comprising soot particles having a particle size distribution characterized by d₂₀ and d₈₀, d₂₀ being a particle size at which 20% of the soot particles are smaller and d₈₀ being a particle size at which 80% of the soot particles are smaller, the d₂₀ of the soot particles being at least 200 Å

and the d₈₀ of the soot particles being at most 1000 Å

, said soot comprising at least 0.1% by weight of the aggregates consisting essentially of ceric oxide crystallites, the largest particle size dimension of which ranging from 50 Å

to 10,000 Å and

the crystallite sizes of which, measured by Debye-Scherrer technique, ranging from 50 Å

to 250 Å

, wherein the soot exhibits an ignition temperature of less than 400°

C.

7. The hydrocarbon fuel soot as defined by claim 6, comprising at least 0.5% by weight of said aggregates of ceric oxide crystallites.

8. The hydrocarbon fuel soot as defined by claim 6, having a total cerium content ranging from 1% to 5% by weight.

9. The hydrocarbon fuel soot as defined by claim 8, having a total cerium content ranging from 1.5% to 2.5% by weight.

10. The hydrocarbon fuel soot as defined by claim 6, the soot comprising soot particles having a particle size characterized by d₅₀, d₅₀ being a particle size at which 50% of the soot particles are smaller and 50% of the soot particles are larger, the d₅₀ of the soot particles ranging from 2000 Å

to 5000 Å

.

11. A vehicular soot trap containing the hydrocarbon fuel soot as defined by claim 6.

12. A process for the production of the aggregates of ceric oxide crystallites comprising burning a hydrocarbon diesel fuel in the presence of at least one cerium compound and collecting a hydrocarbon fuel soot containing at least 0.1% by weight of said aggregates, said aggregates consisting essentially of ceric oxide crystallites, the largest particle size dimension of which ranging from 50 Å

to 10,000 Å and

the crystallite sizes of which, measured by Debye-Scherrer technique, ranging from 50 Å

to 250 Å

, wherein the soot exhibits an ignition temperature of less than 400°

C.

13. The process as defined by claim 12, said at least one cerium compound comprising a cerium (IV) compound.

14. The process as defined by claim 13, said cerium (IV) compound comprising a sol thereof.

15. The process as defined by claim 14, comprising diluting said sol in a concentrated form in said hydrocarbon fuel.

16. The process as defined by claim 12, carried out in an internal combustion engine.

17. The process as defined by claim 16, said at least one cerium compound being formed in situ in said internal combustion engine.