1. A method for producing particles of a compound of interest, said method comprising the steps of:
providing a first solution comprising the compound of interest in a first solvent;
inducing thickening or gelation of the first solution by a process comprising the step of adding a low molecular weight thickener or gelator having a molecular weight of less than 5000 gmol to at least the first solution; and
precipitating the compound of interest in the form of particles not earlier than upon the step of adding the low molecular weight thickener or gelator.
2. The method according to claim 1, further comprising the step of drying the thickened or gelated first solution by a process selected from the group consisting of freeze-drying, spray-drying, centrifuging, and combinations thereof.
3. The method according to claim 1, further comprising the step of isolating the particles from the thickened or gelated first solution.
4. The method according to claim 3, further comprising the step of reversing the thickening or gelation of the first solution without re-dissolving the precipitated particles.
5. The method according to claim 2, wherein the step of drying the thickened or gelated first solution induces precipitation of the compound of interest.
6. The method according to claim 1, wherein the thickener or gelator is dissolved in the first solution.
7. The method according to claim 1, wherein the thickener or gelator is added to said first solution in the form of a second solution in a second solvent, wherein the second solvent is different from the first solvent of the first solution in which the compound of interest is dissolved.
8. The method according to claim 1, wherein gelation or thickening is induced by the presence of a first solvent andor a second solvent in which the gelator or thickener is essentially not soluble.
9. The method according to claim 8, wherein the solvent in which the gelator or thickener is essentially not soluble is the first solvent in which the compound of interest is dissolved.
10. The method according to claim 8, wherein the gelator or thickener is essentially not soluble in the second solvent, which is different from the first solvent in which the compound of interest is dissolved and which is added to the first solution.
11. The method according to claim 7, wherein the compound of interest is essentially insoluble in the second solvent.
12. The method according to claim 1, wherein the compound of interest is selected from the group consisting of pharmaceuticals, peptides, nucleic acids, proteins, enzymes, growth factors, steroids, hormones, antibiotics, gene therapy agents, catalysts, adsorbents, pigments, coatings, personal care products, abrasives, particles for sensors, metals, alloys, ceramics, membrane materials, nutritional substances, anti-cancer agents, fertilizers, pesticides, herbicides, and combinations thereof.
13. The method according to claim 12, wherein the compound of interest is a biologically or pharmaceutically active compound.
14. The method according to claim 12, wherein the compound of interest has a low solubility in water.
15. The method according to claim 1, wherein the thickener or gelator is selected from the group consisting of organogelators, comprising hydroxylated carboxylic fatty acids, the amides of carboxylic acids, N,N-dibenzoyl-L-cystine, ureido derivatives, N-acyl amino acids and derivatives, amines of steroids, amides of steroids, and sorbitols.
16. The method according to claim 1, wherein the thickener or gelator is a thickener and gelator represented by formula I:
wherein
A represents a cycloalkyl, a heterocycloalkyl, an aromatic or heteroaromatic moiety;
each of X1, X2 and X3 is independently selected from the group consisting of the moieties \u2014N(H)\u2014, \u2014C(O)\u2014, \u2014O(CO)\u2014, \u2014OC(S)\u2014, \u2014C(S)\u2014, \u2014NHC(S)\u2014 and \u2014NH\u2014C(O)\u2014;
each of Am1, Am2, and Am3 is a moiety selected from the group consisting of an amino acid, a derivative of an amino acid, a number of amino acids, and derivatives of a number of amino acids;
each of Y1, Y2, and Y3 is independently selected from the group consisting of \u2014OR, \u2014N(OH)R, and \u2014NR2, if the corresponding X (X1 for Y1, X2 for Y2, and X3 for Y3) is \u2014(O)\u2014 or \u2014NH\u2014C(O)\u2014 and n=1, and each of Y1, Y2, and Y3 is independently selected from the group consisting of \u2014C(O)R, \u2014C(O)\u2014NR2, \u2014C(O)\u2014OR, \u2014C(S)R, \u2014C(S)\u2014NR2\u2014C(S)\u2014OR and R, if the corresponding X (X1 for Y1, X2 for Y2, and X3 for Y3) is \u2014NH\u2014 and n=1 or 2, wherein each R is independently H, or a substituted or unsubstituted, branched, cyclic or straight alkyl, alkenyl or alkynyl group or wherein each R is independently H, or a substituted or unsubstituted, branched, cyclic or straight alkyl, alkenyl or alkynyl group comprising an aromatic, ester or ether moiety or one or more other heteroatoms and having 1 to 40 carbon atoms; and n is 1 or 2.
17. The method according to claim 16, wherein each Y is independently selected from the group consisting of \u2014OH, \u2014O\u2014(CH2)i\u2014OH, \u2014NH2\u2014NH(CH2)iO(CH2)jOH, \u2014O(CH2)iO(CH2)jOH, \u2014NHOH and \u2014NH(CH2)iOH, wherein i and j are independently 1, 2, 3, 4, 5, 6, 7, or 8.
18. The method according to claim 1, wherein the thickener or gelator is a non-symmetrical, trisubstituted cyclic thickener or gelator selected from Formula II or Formula III,
wherein said cyclic thickener or gelator is substituted by at least one X\u2014Am\u2014Yn groups and at least one other substituent is \u2014X-Z groups
wherein
each X is independently selected from the group consisting of \u2014N(H)\u2014, \u2014C(O)\u2014, \u2014OC(S)\u2014, \u2014C(S)\u2014, \u2014NHC(S)\u2014 and \u2014NH\u2014C(O)\u2014;
each of Am1, Am2, and Am3 is a moiety selected from the group consisting of an amino acid, a derivative of an amino acid, a number of amino acids, and derivatives of a number of amino acids;
each Y is independently selected from the group consisting of \u2014OR, \u2014N(OH)R, \u2014NR2\u2014C(O)R, \u2014C(O)\u2014NR2, \u2014C(O)OR, \u2014C(S)R, \u2014C(S)\u2014NR2\u2014C(S)\u2014OR and R, wherein each R is independently defined as in claim 16
each Z is independently selected from the group consisting of \u2014OH, \u2014COOH, \u2014C(O)NHR, \u2014NHC(O)R and \u2014NHR, wherein each R is independently defined as in claim 16; and n=1 or 2.
19. The method according to claim 16, wherein X1, X2, and X3, are each independently selected from the group consisting of \u2014N(H)\u2014, \u2014C(O)\u2014, \u2014O(CO)\u2014, and \u2014NH\u2014C(O)\u2014.
20. The method according to claim 16, wherein the thickener or gelator is selected from the group consisting of a 1,3,5-substituted cyclohexane, a 1,3,5-substituted benzene, a 1,3,5-substituted cyclohexane wherein all three substituents are in an equatorial plane, and a 1,3,5-substituted benzene wherein all three substituents are in an equatorial plane.
21. The method according to claim 18, wherein \u2014X-Z is selected from the group consisting of \u2014COOH, \u2014C(O)\u2014NH2, \u2014C(O)\u2014NHCH3, \u2014C(O)\u2014NH\u2014(CH2)2\u2014OH, \u2014C(O)\u2014NH\u2014(CH2)2\u2014O\u2014(CH2)2\u2014OH, and C(O)NHCH2-pyr.
22. The method according to claim 16, wherein each Y is independently selected from the group consisting of \u2014OCH3, \u2014OCH2CH3, \u2014NHCH2CH2OCH2CH3, \u2014OCH2CH2OCH2CH3, \u2014NHCH3, \u2014NHCH2CH3, \u2014NH(CH2)2CH3, \u2014NHCH2Ph, \u2014NIT-Ph-O\u2014CH3, \u2014O-naphthyl, \u2014NH-naphthyl, and \u2014NH-quinoline.
23. The method according to claim 16, wherein each Am is independently selected from the group consisting of leucine, isoleucine, lysine, valine, proline, methionine, glycine, histidine, alanine, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, glutamine, aspartic acid, glutamic acid, arginine, and derivatives thereof.
24. The method according to claim 1, wherein the gelator or thickener cross-links during the induction of thickening or gelation.
25. The method according to claim 1, wherein the first solution is gelled and the gelation of the first solution is induced at the step of adding the gelator to the first solution.
26. The method according to claim 1, wherein the compound of interest is dissolved in a solvent selected from the group consisting of aromatic hydrocarbons, non-aromatic hydrocarbons, alcohols, ethers, esters, aldehydes, ketones, alkanoic acids, epoxides, amines, amides, halogenated hydrocarbons, silicon oils, vegetable oils, phoshoric acids, sulfoxides, nitriles, water, and mixtures of any thereof.
27. The method according to claim 26, wherein the first solvent is selected from the group consisting of water, DMF, NMP, DMSO, ethanol, acetonitrile, propylene glycol and polyethylene glycol.
28. The method according to claim 7, wherein the second solvent is selected from the group consisting of aromatic hydrocarbons, non-aromatic hydrocarbons, alcohols, ethers, esters, aldehydes, ketones, alkanoic acids, epoxides, amines, amides, halogenated hydrocarbons, silicon oils, vegetable oils, phoshoric acids, sulfoxides, nitriles, water, and mixtures of any thereof.
29. The method according to claim 1, wherein thickening or gelation of the first solution andor second solution is aided by sonication, a chemical trigger, a pH change, a temperature change, light or by adding a non-solvent for the gelatorthickener.
30. The method according to claim 1, wherein thickening or gelation of the first solution andor second solution is aided by increasing the amount of thickener or gelator in the first solution andor the second solution.
31. The method according to claim 1, wherein a third solution containing the compound of interest is added to a thickened or gelated solution of the thickener or gelator.
32. The method according to claim 1, wherein the thickener or gelator, the compound of interest, and the first solvent andor the second solvent are brought into contact with each other in a first solution andor a second solution, said method further comprising the steps of
raising the temperature of the first solution andor the second solution, dissolving the compound of interest in the first solution andor the second solution, and
cooling the resultant solution to at least a temperature wherein the resultant solution is at least partially thickened or gelated.
33. A particle of a compound of interest obtainable by the method according to claim 1.
34. The particle of a compound of interest of claim 33 having a particle size in the range selected from the group consisting of from about 1 nm to 100 \u03bcm, from about 1 nm to about 250 nm, and from about 1 nm to about 100 nm.
35. A gel or thickened solution comprising at least one particle of claim 34.
36. The gel or thickened solution of claim 35, further comprising a thickener or a gelator selected from the group consisting of organogelators, comprising hydroxylated carboxylic fatty acids, the amides of carboxylic acids, N,N-dibenzoyl-L-cystine, ureido derivatives, N-acyl amino acids and derivatives, amines of steroids, amides of steroids, and sorbitols.
37. The method according to claim 24, wherein the thickener or gelator comprises a cross-linkable reactive group selected from the group consisting of a \u2014C\u2550C\u2014 group or a \u2014SH group.
38. The method according to claim 18, wherein X1, X2, and X3, are independently selected from the group consisting of \u2014N(H)\u2014, \u2014C(O)\u2014, \u2014O(CO)\u2014, and \u2014NH\u2014C(O)\u2014.
39. The method according to claim 18, wherein the thickener or gelator is selected from the group consisting of a 1,3,5-substituted cyclohexane, a 1,3,5-substituted benzene, a 1,3,5-substituted cyclohexane wherein all three substituents are in an equatorial plane, and a 1,3,5-substituted benzene wherein all three substituents are in an equatorial plane.
40. The method according to claim 18, wherein each Y is independently selected from the group consisting of \u2014OCH3, \u2014OCH2CH3, \u2014NHCH2CH2OCH2CH3, \u2014OCH2CH2OCH2CH3, \u2014NHCH3, \u2014NHCH2CH3, \u2014NH(CH2)2CH3, \u2014NHCH2Ph, \u2014NIT-Ph-O\u2014CH3, \u2014O-naphthyl, \u2014NH-naphthyl, and \u2014NH-quinoline.
41. The method according to claim 18, wherein each Am is independently selected from the group consisting of leucine, isoleucine, lysine, valine, proline, methionine, glycine, histidine, alanine, phenylalanine, tryptophan, serine, threonine, cysteine, tyrosine, asparagine, glutamine, aspartic acid, glutamic acid, arginine, and derivatives thereof.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A composition mainly consisting of cerium oxide and of at least one oxide of another rare earth, characterized in that it has a specific surface area of at least 20 m2g after calcining at 1000\xb0 C. for 5 hours.
2. The composition according to claim 1, characterized in that it has a specific surface area of at least 22 m2g after calcining at 1000\xb0 C. for 5 hours.
3. The composition according to claim 1, characterized in that it has a specific surface area of at least 10 m2g after calcining at 1100\xb0 C. for 5 hours.
4. The composition according to claim 1, characterized in that it has a specific surface area of at least 14 m2g after calcining at 1100\xb0 C. for 5 hours.
5. The composition according to claim 1, characterized in that it has a specific surface area of at least 30 m2g after calcining at 900\xb0 C. for 5 hours.
6. The composition according to claim 1, characterized in that the other rare earth is yttrium, neodymium, lanthanum, praseodymium or these last two elements in combination.
7. The composition according to claim 1, characterized in that it has, after calcining at 1000\xb0 C. for 5 hours, a pore volume of at least 0.15 cm3g, provided by pores having a diameter of at most 200 nm.
8. The composition according to claim 1, characterized in that it has, after calcining at 1000\xb0 C. for 5 hours, a pore volume of at least 0.10 cm3g, provided by pores having a diameter of at most 50 nm.
9. The composition according to claim 1, characterized in that it has, after calcining at 1000\xb0 C. for 5 hours, a pore volume of at least 0.2 cm3g provided by pores having a diameter of at most 200 nm.
10. The composition according to claim 1, characterized in that it has, after calcining at 1000\xb0 C. for 5 hours, a pore volume of at least 0.15 cm3g provided by pores having a diameter of at most 50 nm.
11. The composition according to claim 1, wherein the total content of the at least one oxide of another rare earth is at most 25% by weight of the composition.
12. The composition according to claim 1, wherein the total content of the at least one oxide of another rare earth is at most 20% by weight of the composition.
13. The composition according to claim 1, wherein the total content of the at least one oxide of another rare earth is at most 15% by weight of the composition.
14. A method for preparing a composition mainly consisting of cerium oxide and of at least one oxide of another rare earth, characterized in that it has a specific surface area of at least 20 m2g after calcining at 1000\xb0 C. for 5 hours, the method comprising the following steps:
forming a first liquid medium comprising a cerium compound;
heating the first liquid medium to a temperature of at least 100\xb0 C. to form a precipitate in the first liquid medium;
separating the precipitate from the first liquid medium;
forming a second liquid medium comprising the separated precipitate and a compound of the other rare earth;
heating the second liquid medium to a temperature of at least 100\xb0 C. to form a reaction medium;
adjusting the pH of the reaction medium so that it is brought to a basic pH; and
separating the precipitate from the basic reaction medium and calcining said precipitate to yield the composition mainly consisting of cerium oxide and of at least one oxide of another rare earth.
15. The method according to claim 14, wherein the cerium compound is selected from the group consisting of cerium nitrates, cerium sulphates, cerium acetates, cerium chlorides and ceric ammonium nitrate, and the other rare earth compound is selected from the group consisting of nitrates, sulphates, acetates, and chlorides of the rare earth element.
16. A catalytic system, characterized in that it comprises a composition mainly consisting of cerium oxide and of at least one oxide of another rare earth, characterized in that it has a specific surface area of at least 20 m2g after calcining at 1000\xb0 C. for 5 hours.
17. A method for treating exhaust gas of an internal combustion engine, the method comprising contacting the exhaust gas with a catalyst mainly consisting of cerium oxide and of at least one oxide of another rare earth, characterized in that it has a specific surface area of at least 20 m2g after calcining at 1000\xb0 C. for 5 hours.