Metal-exchanged carboxylato-alumoxanes and process of making metal-doped alumina

• US 6,207,130 B1
• Filed: 04/10/1998
• Issued: 03/27/2001
• Est. Priority Date: 04/11/1997
• Status: Expired due to Fees

• Current Assignee: Rice University, Tda Research, Inc.
• Original Assignee: Rice University, Tda Research, Inc.
• Inventors: Barron, Andrew R., Bai, Chuansheng, Kareiva, Aivaras, Cook, Ronald L., Harlan, Charles Jeffrey, MacQueen, D. Brent
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US09/058,587
• Time in Patent Office: 1,082 Days
• Field of Search: 534/13, 534/16, 556/27, 556/179, 423/600, 423/263, 423/252, 423/253, 423/594, 423/598, 423/599
• US Class Current: 423/600
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01F 17/34 Aluminates, e.g. YAlO3 or Y3-xGdxAl5O12
• CPC Class Codes: C01F 7/04 Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom C01F7/028 takes precedence
• CPC Class Codes: C01F 7/16 Preparation of alkaline-earth metal aluminates or magnesium aluminates; Aluminium oxide or hydroxide therefrom C01F7/028 takes precedence
• CPC Class Codes: C01F 7/30 Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
• CPC Class Codes: C01F 7/78 Compounds containing aluminium and two or more other elements, with the exception of oxygen and hydrogen aluminates C01F7/02; compounds containing aluminium, fluorine and alkali or alkaline earth metals C01F7/54; nitrates containing other cations besides aluminium C01F7/66; sulfides, sulfites or sulfates containing other cations besides aluminium C01F7/70 - C01F7/74
• CPC Class Codes: C01G 1/00 Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general electrolytic production of inorganic compounds C25B1/00
• CPC Class Codes: C01G 45/006 Compounds containing, besides manganese, two or more other elements, with the exception of oxygen or hydrogen manganates, manganites or permanganates C01G45/12
• CPC Class Codes: C01G 51/006 Compounds containing, besides cobalt, two or more other elements, with the exception of oxygen or hydrogen cobaltates C01G51/40
• CPC Class Codes: C01P 2002/32 spinel-type (AB2O4)
• CPC Class Codes: C01P 2002/34 perovskite-type (ABO3)
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C07F 15/025 without a metal-carbon linkage
• CPC Class Codes: C07F 15/045 without a metal-carbon linkage
• CPC Class Codes: C07F 15/065 without a metal-carbon linkage
• CPC Class Codes: C07F 5/069 without C-aluminium linkages

Abstract

A method has been developed for the solution-based metal exchange of carboxylato-alumoxanes [Al(O)_x(OH)_y(O₂CR)_z]_n with a wide range of metal cations. Metal-exchanged carboxylato-alumoxanes are new, particularly those in which about 10% to about 50% or more of the Al ions are exchanged for other metal ions. Additionally, the carboxylic acid ligands can be stripped from the boehmite core of metal-exchanged carboxylato-alumoxanes at low temperature leading to the formation of metal-exchanged boebmite particles. These new material phases can be used as intermediates for preparation of mixed metal aluminum oxide materials. Thermolysis of the metal-exchanged carboxylato-alumoxanes or metal-exchanged boehmite particles results in doped aluminas (M/Al₂O₃), binary (MAlO_x), ternary (MM′AlO_x) and even more complex metal aluminum oxide compounds, where M and M′ are metal ions other than those of aluminum and are preferably those of Lanthanide metals or transition metals. The method allows preparation of pure phase materials as well as the preparation of metastable metal aluminum oxide phases. The carboxylato-alumoxanes are prepared by the reaction of boehmite (or pseudoboehmite) with carboxylic acids in a suitable solvent. Up to at least half of the aluminum cations in the boehmite lattice of the carboxylato-alumoxanes can be replaced by the reaction of metal acetylacetonates with the carboxylato-alumoxane in a suitable solvent. The metal exchange reaction can also be carried out by reaction with soluble metal salts. Reactions of boehmite with the metal acetylacetonates (or soluble metal salts) do not lead to the metal exchange reaction observed for the carboxylato-alumoxanes.

Claims

1. A metal-exchanged carboxylato-alumoxane.

2. The metal-exchanged carboxylato-alumoxane of claim 1 wherein 10% or more of the aluminum ions of the alumoxane are replaced with another metal ion or other metal ions.

3. The metal-exchanged carboxylato-alumoxane of claim 1 wherein from about 10% to about 50% of the aluminum ions of the alumoxane are replaced with another metal ion or other metal ions.

4. The metal-exchanged carboxylato-alumoxane of claim 1 wherein the exchanged metal is a metal ion selected from the group Ca²⁺, Sr²⁺, Co²⁺, Ni⁺, Mg²⁺, Fe³⁺ or Cu²⁺ and mixtures thereof.

5. The metal-exchanged carboxylato-alumoxane of claim 1 wherein the exchanged metal is a metal selected from the group of the lanthanide metals.

6. The metal-exchanged carboxylato-alumoxane of claim 1 which comprises a monocarboxylic acid ligand RCO₂ wherein the R group is an alkyl group, alkene group or aromatic group optionally substituted with hetero-atom functional groups.

7. The metal-exchanged carboxylato-alumoxane of claim 1 which comprises a monocarboxylic acid ligand RCO₂ wherein the R group is an ether or halo-substituted alkyl, alkene or aromatic group.

8. The metal-exchanged carboxylato-alumoxane of claim 1 wherein the exchanged metal is an alkaline metal ion, an alkaline earth metal ion, a transition metal ion, an actinide metal ion, a Group III B metal ion, a Group IVB metal ion or mixtures thereof.

9. The metal-exchanged carboxylato-alumoxane of claim 1 wherein the exchanged metal is Na⁺, K⁺, or their mixtures with Li⁺ or Mg²⁺.

10. The metal-exchanged carboxylato-alumoxane of claim 1 which comprises two exchanged metal ions other than aluminum.

11. The metal-exchanged carboxylato-alumoxane of claim 1 comprising Ce³⁺ or Mn²⁺.

12. The metal-exchanged carboxylato-alumoxane of claim 1 which comprises a monocarboxylic acid ligand RCO₂ wherein the R group is an alkyl group, alkene group or aromatic group.

13. The metal-exchanged carboxylato-alumoxane of claim 1 wherein the exchanged metal is selected from the group Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ti⁴⁺, V³⁺, Mn²⁺, Fe²⁺, Fe³⁺Co²⁺, Ni⁺, Cu²⁺, Zn²⁺, Ga³⁺, Y³⁺, Zr⁴⁺, Nb³⁺, Ag⁺, Cd²⁺, In³⁺, Sn²⁺, Hf³⁺, Re³⁺, Hg²⁺, Pb²⁺, La³⁺, Ce³⁺, Nd³⁺, Pr³⁺, Th⁴⁺, U^{4 +} and mixtures thereof.

14. The metal-exchanged carboxylato-alumoxane of claim 1 that is formed by metal exchange of a carboxylato-alumoxane with a metal acetylacetonate.

15. The metal-exchanged carboxylato-alumoxane of claim 1 that is formed by metal exchange of a carboxylato-alumoxane with a metal salt.

16. A method for making a metal-exchanged carboxylato alumoxane which comprises the steps of:

(a) combining a carboxylato-alumoxane wherein the carboxylic acid ligands are monocarboxylic acid ligands with a metal acetoacetonate or mixture of metal acetoacetonates solubilized or dispersed in a solvent to effect a metal-exchange reaction and

(b) isolating said metal-exchanged carboxylato-alumoxane.

17. The method of claim 16 further comprising the step of preparing said carboxylato-alumoxane by reaction of boehmite or pseudoboehmite with a monocarboxylic acid.

18. The method of claim 16 wherein said carboxylato-alumoxane is water soluble and said combination is solubilized or dispersed in water.

19. The method of claim 16 wherein said carboxylato-alumoxane is soluble in dichloromethane or tetrahydrofuran and said combination is solubilized or dispersed in dichloromethane or tetrahydrofuran.

20. The method of claim 16 wherein said carboxylato-alumoxane comprises a ligand wherein said carboxylic acid ligand is acetate, gluconate, methoxy(ethoxyethoxy) acetate, hexanoate, dimethoxy benzoate, or laurate.

21. A method for preparing a metal-doped binary or tertiary alumina which comprises the step of heating a metal-exchanged carboxylato-alumoxane prepared by the method of claim 16 to strip the carboxylic acid ligands therefrom or form said alumina.

22. The method of claim 21 wherein the binary or tertiary alumina is a γ

-alumina.

23. The method of claim 21 wherein the heating step is performed at temperatures ranging from 325°

C. to 600°

C.

24. The method of claim 21 wherein the heating step is performed at temperatures ranging from 800°

C. to 1700°

C.

25. The method of claim 21 wherein, in the metal-exchanged carboxylato-alumoxane, the exchanged metal is a metal ion selected from the group Ca²⁺, Sr²⁺, Co²⁺, Ni⁺, Mg²⁺, Fe³⁺, Cu²⁺ and mixtures thereof.

26. The method of claim 21 wherein, in the metal-exchanged carboxylato-alumoxane, the exchanged metal is a lanthanide metal.

27. The method of claim 21 wherein, in the metal-exchanged carboxylato-alumoxane, the exchanged metal is an alkaline metal ion, an alkaline earth metal ion, a transition metal ion, an actinide metal ion, a Group III B metal ion, a Group IVB metal ion and mixtures thereof.

28. The method of claim 21 wherein the metal-doped alumina is selected from those having the compositions:

M_aM′

_bAlO₃, where a=0-1, b=0-1, and a+b=1;

M_aM′

_bAl₂O₄, where a=0-1, b=0-1, and a+b=1;

(M_aM′

_b)Al₅O₁₂, where a=0-3, b=0-3, and a+b=3; and

M_aM′

_bAl₁₁O₁₈, where a=0-1, b=0-1, and a+b=1 and wherein M_a and M′

_b represent different metals, and are not aluminum.

29. The method of claim 16 further comprising the step of heating the combination of step (a) at or below the boiling point of the solvent.