# Patent

## Title
Boehmitic aluminas and high-temperature stable, high-porosity, pure-phase aluminium oxides obtained therefrom

## Abstract

This invention relates to crystalline boehmitic aluminas the crystallites of which exhibit unusual dimensional differences in the space directions 020 and 120. This invention further relates to a method for preparing such aluminas and the follow-up products obtained therefrom by calcination.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/913,802, filed on Aug. 6, 2004 now abandoned for Boehmitic Aluminas and High-Temperature Stabile, High-Porosity, Pure Phase Aluminum Oxides Obtained Therefrom, which is a continuation of U.S. patent application Ser. No. 09/529,484, filed Jun. 9, 2000 (now U.S. Pat. No. 6,773,690), which is a national phase of PCT/DE99/02464 filed Aug. 5, 1999, which claims priority to German application DE19836281.6, filed Aug. 14, 1998, the disclosures of which are incorporated herein by reference.


BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to crystalline boehmitic aluminas the crystallites of which exhibit unusual dimensional differences in the space directions 020 and 120. This invention further relates to a method for preparing such aluminas and the follow-up products obtained therefrom by calcination.
2. Description of the Prior Art
The structural relations of the various aluminium oxides and aluminium hydroxides are very complex. Main distinctions are made between α-Al2O3 (corundum), α-AlO(OH) (diaspore), α-Al(OH)3 (occasionally also termed βAl(OH)3, bayerite, or bauxite dihydrate), γ-Al2O3, γAl(OH) (boehmite), and γ-Al(OH)3 (occasionally also termed α-Al(OH)3, gibbsite, hydrargillite). In addition, there exist numerous modifications thereof, particularly modifications of different aluminium oxides obtained by thermal degradation of the aluminium hydroxides or aluminium oxide hydrates. For instance, it is generally believed that boehmitic alumina will undergo the following conversion under the influence of temperature:

Boehmite→γ(gamma)-Al2O3→δ(delta)-Al2O3→θ(theta)-Al2O3→α(alpha)-Al2O3 

In literature references there are no standardized designations for the various aluminium oxides, aluminium oxide hydrates (occasionally also termed aluminium oxide hydroxides), and aluminium hydroxides, particularly with respect to the preceding Greek characters. The term ‘boehmitic aluminas’ as used herein comprises boehmitic and pseudo-boehmitic aluminas.
Boehmitic aluminas are known. High-purity boehmitic aluminas can be prepared for example by controlled hydrolysis of aluminium alkoxides. The resultant aluminium hydroxide hydrogels crystallize for example in the form of the rhombic aluminium oxide hydrate crystallite (γ-AlO(OH), boehmitic alumina).
DE 38 23 895-C1 discloses a process for producing boehmitic aluminas with pore radii which can be adjusted in a controlled way from 3 to 100 nm. According to said process, the boehmitic aluminas are subjected to hydrothermal aging at a steam pressure from 1 to 30 bar (corresponding to a temperature from 100 to 235° C.) for 0.5 to 20 hours with agitation at a peripheral velocity from 1 to 6 s−1. Such aluminas and the boehmitic aluminas produced by other processes have crys-tallite sizes (measured on the 020 reflex) which are always smaller by at least 2 nm compared to the crystallite sizes measured on the 120 reflex. In U.S. Pat. No. 3,898,322, too, a process for producing hydrothermally aged alumina suspension is described. According to said process, the aqueous aluminium hydroxide/aluminium oxide hydrate suspension obtained by hydrolysis of the aluminium alkoxides is subjected to hydrothermal aging at room temperature for 2 to 60 hours.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide boehmitic aluminas having unusual morphologies. It is a further object of this invention to provide aluminium oxides with unusual high-temperature stabilities and, furthermore, with extraordinarily large surfaces and pore volumes after calcination.
The problem is solved by crystalline boehmitic alumina with a crystallite size measured in nm on the 020 reflex which is larger than the crystallite size which is smaller by 1.5 nm, preferably 0.5 nm, measured on the 120 reflex.
It is particularly preferred that the crystallite size measured in nm on the 020 reflex be larger than the crystallite size measured in nm on the 120 reflex.
It is a further object of the present invention to provide methods for preparing the crystalline boehmitic aluminas of the instant invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The starting compounds employed for preparing the crystalline boehmitic aluminas of the present invention are conventional (i.e. crystalline, partially crystalline, or amorphous) aluminium-oxygen compounds, such as aluminium oxide hydrates, aluminium hydroxides, or mixtures thereof with aluminium oxides, preferably conventional pseudo-boehmitic and/or boehmitic aluminas. When using commercial aluminium-oxygen compounds produced by other processes, or when the boehmitic alumina is not produced and is readily employed, for example as a hydrogel, it is preferred that the aluminium-oxygen compounds be subjected to grinding prior to aging according to this invention.
The starting compounds are aluminium oxide hydrates (or aluminium oxide hydroxides) which are preferably prepared by hydrolysis of aluminium alkoxides obtained from C1 to C24+ alcohols or mixtures thereof. The aluminium alkoxides can be prepared for example by the Ziegler process.
The aluminium alkoxides are hydrolyzed in an aqueous environment. Generally, the hydrolysis can be performed in a temperature range from 30 to 150° C., preferably 60 to 100° C. The resultant aluminium oxide hydrate suspension is then separated from the aqueous alcohol phase. The alumina-water phase may contain for example alumina hydrate with an Al2O3 content from 5 to 12 wt.%, preferably 10 to 11 wt. %.
The aluminium-oxygen compounds employed as starting materials may also originate from natural resources or can be produced by other processes, e.g. the amalgam process.
The crystalline boehmitic aluminas of the present invention can be prepared by long-time hydrothermal aging of oxygen compounds of the aluminium, particularly aluminium oxide hydrates, in the presence of water at temperatures from 60 to 240° C., preferably 70 to 160° C., most preferably 70 to 110° C. for at least 10 hours, preferably at least 20 hours, most preferably at least 24 to 70 hours or 30 to 60 hours. It is desirable to keep the shear stress on the aluminium oxide hydrate suspension low during the production. The term ‘low shear stress’ used herein means the shear stress caused by an agitator, e.g. a propeller agitator, running at a peripheral velocity of 0.5 to 3 m/s. The particle size of the aluminium oxide hydrates in the suspension is preferably in the range from 1 to 12 microns, most preferably from 6 to 12 microns.
According to another embodiment of the present invention, the crystalline boehmitic aluminas of this invention can be prepared by hydrothermal aging in the presence of water and at least bidentate, preferably at least tridentate bases, which are preferably nitrogen bases, and at temperatures from 30 to 240° C., preferably 70 to 160° C., for 0.5 to 170 hours. Examples thereof are diethylene triamine, dipropylene triamine, triethylene tetramine (triene), tetraethylene pentamine (tetrene), and pentaethylene hexamine (pentrene).
According to yet another embodiment of the present invention, the crystalline boehmitic aluminas of this invention can be prepared by long-time hydrothermal aging in the presence of water and metallic or nonmetallic oxides, or oxide hydrates, except for aluminium oxide or aluminium oxide hydrates, and water at 40 to 240° C., preferably 70 to 160° C., for at least 8 hours, preferably 16 to 170 hours, most preferably 32 to 170 hours.
Preferably, said metallic or nonmetallic oxides or oxide hydrates are those of silicon, zirconium, titanium, lanthane, and/or boron. Examples thereof are SiO2, ZrO2, TiO2, and B2O3. Such oxides are added in quantities from 0.1 to 5 wt.%, preferably 0.2 to 2 wt.%, referring to Al2O3.
It is preferred that the crystalline boehmitic aluminas of the present invention or the aluminium oxides prepared therefrom be free from any foreign atoms, particularly other metal atoms (including silicon and phosphorus), i.e. said materials should exclusively consist of aluminium, oxygen, and/or hydrogen in quantities of greater than 99 atom %, preferably greater than 99.9 atom %.
Preferably, the crystalline boehmitic aluminas of the present invention, independently of one another, have the following characteristics: pore volumes of greater than 0.8 cm3/g, preferably greater than 0.9 cm3/g, crystallite sizes (measured on the 020 reflex) of greater than 10 nm, preferably greater than 12 nm, and surfaces of greater than 150 m2, preferably 150 to 200 m2. In contrast thereto, it is preferred that the crystalline boehmitic aluminas of the present invention prepared according to the third embodiment, independently of one another, have the following characteristics: pore volumes of greater than 0.7 cm3/g, preferably greater than 0.9 cm3/g, crystallite sizes (measured on the 020 reflex) from about 6 to 10 nm, and surfaces of greater than 200 m2.
The aluminium oxides prepared from the crystalline aluminas of the present invention by thermal treatment at higher than 150° C., preferably by calcination at temperatures from 800 to 1,500° C. for at least 0.5 hour are a further object of the present invention. Said aluminium oxides are distinguished by their particularly large surfaces, large pore volumes, and excellent high-temperature stabilities. The term ‘thermal stability’ employed herein means stability to changes in the surface or crystalline phase brought about by external influences, such as water, chemicals, pressure, or mechanical stress and temperature.
Furthermore, the aluminium oxide hydrates and aluminium oxides according to the present invention are pure-phase and stable-phase products which are present as delta, theta, or alpha modifications, depending on the calcination time and temperature. More details are presented in the tables 1, 2, and 3 showing the powder diffraction pattern data of the different aluminium oxides of this invention.
The term ‘pure-phase’ employed herein means that more than 90 wt.%, preferably more than 98 wt.% of the crystalline aluminium oxide consists of a single phase (determined by X-ray powder diffraction). The theta-aluminium oxides of the present invention are pure-phase products on the condition that particularly the d-values (as Å) do not present any peaks in the X-ray powder diffraction pattern which are characteristic of α-Al2O3.
With respect to the X-ray powder diffraction patterns of conventional aluminium oxides, reference is made to the corresponding JCPDS sheets (US National Bureau of Standards) for corundum (α-Al2O3), delta- and theta-aluminium oxide.
The term ‘stable-phase’ employed herein means that the crystalline phase will not change even if the product is exposed for a long time to the same or lower temperature used in the production of said aluminium oxide by calcination.
Furthermore, the aluminium oxides of the present invention are temperature-stable and, contrary to conventional aluminium oxides, have surfaces of larger than 60 m2/, preferably larger than 70 m2/g, even after calcination at 1,200° C. for 3 hours. The calcination is performed in heated air in a muffle furnace.
The aluminium oxides of the present invention have pore volumes of greater than 0.6 cm3/g, preferably from 0.7 to 1 cm3/g (determined by the mercury penetration method in accordance with DIN 66 133) within a pore radius range from 1.8 to 100 nm. The aluminium oxides of this invention keep said characteristic even after exposure to temperatures of 1,100° C. for 24 hours. Conventional aluminium oxides, e.g. those obtained by calcination of bayerite, present distinctly smaller pore volumes (about 0.2 to 0.4 cm3/g).
The aluminium oxides of this invention are most useful as catalysts or catalyst supports, particularly as support material for automobile exhaust gas catalysts. In this case the catalyst support is treated with noble metal catalysts, such as platinum or palladium.
When using the aluminium oxides of this invention, the catalyst or catalyst support can be applied in thin layers which remain stable even at high temperatures, e.g. of greater than 1,000° C. This characteristic is most advantageous in exhaust gas catalyst applications. Furthermore, stabilization aids, such as lanthane oxide or SiO2, employed in technical applications can mostly be dispensed with. Stabilization aids made of metal oxides may have adverse effects on the catalytic behavior of the Al2O3 catalyst or catalyst support.
The crystallite sizes of the boehmitic aluminas according to this invention were determined on the 120 and 020 reflexes using the general Scherrer formula:










Crystallite size = (K × lambda × 57.3)/(beta × cos theta)


















K (form factor):
0.992



Lambda (X-ray wave length):
0.154 nm



Beta (corrected line broadening of apparatus):
reflex-




dependent



Theta:
reflex-




dependent










The measurements were carried out using a Philips XRD X'pert apparatus. The measurement parameters for the samples obtained in Example 1 (Comparative Example) and Example 2 have been compiled in Tables 1 and 2, respectively.
The reflexes 120 and 020 (Miller indices) were determined on the boehmite and relate to the unconventional crystallographic Amam mounting of orthorhombic space group no. 63. The conventional mounting is Cmcn, wherein the a- and c-axes have been exchanged in comparison with the unconventional Amam mounting.
The surface areas of the aluminium oxides of this invention were determined by the N2 sorption method (BET method in accordance with DIN 66131). The pore volumes and pore volume distributions were determined by the mercury intrusion (penetration) method in accordance with DIN 66133 using a mercury porosimeter. The pore volumes were reported as cumulative volumes in cm3/g in accordance with DIN 66133.


EXAMPLE 1
Comparative Example
First, an alumina slurry to be employed as the starting material was prepared by neutral aluminium alcoholate hydrolysis:
An aluminium alcoholate mixture obtained as an intermediate in the Ziegler/Alfol process was hydrolyzed with water which had been liberated from foreign ions in a demineralization unit. The hydrolysis was performed at 90° C. in an agitated kettle. The resultant two phases, i.e. the upper alcohol phase and the lower alumina/water phase, were immiscible.
500 grams of this alumina slurry (pH 9) containing 10 to 11 wt. % Al2O3 were added in portions to a reactor operated at a pressure of 3 bar corresponding to 115° C. After the reaction conditions had been adjusted, the slurry was allowed to age for 4 hours using a standard agitator running at a peripheral velocity of 1.6 m/s corresponding to an agitator speed of 500 r.p.m.
The following values were obtained:
















Reflex
Beta
Theta
Crystallite Size









120
0.919
14°
9.8 nm



020
0.919
 7°
6.7 nm







The 120 reflex is greater by 3.1 nm than the 020 reflex.






The specific surface was determined by the N2 sorption method (BET method). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 46 m2/g. The X-ray powder diffraction pattern of said sample is shown in Table 1. It presents significant alpha-phase signals.
EXAMPLE 2
500 grams of the alumina slurry (pH 9) containing 10 to 11 wt. % Al2O3 as defined in the Comparative Example were added in portions to a reactor operated at normal pressure and 98° C. After the reaction conditions had been adjusted, the slurry was allowed to age for 16 hours using a standard agitator running at a peripheral velocity of 1.6 m/s corresponding to an agitator speed of 500 r.p.m. The crystallite sizes measured as described in the Comparative Example were 13.5 nm (120 reflex) and 12.1 nm (020 reflex).
After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 68 m2/g. The X-ray powder diffraction pattern of this sample is shown in Table 1. It presents theta-phase signals. The aluminium oxide is present in the theta phase with a phase purity of greater than 98%.
After aging for 20 hours under the conditions specified hereinabove the crystallite sizes were found to be 13.5 nm (120 reflex) and 13.0 nm (020 reflex).
EXAMPLE 3
500 grams of the alumina slurry (pH 9) containing 10 to 11 wt.% Al2O3 as defined in the Comparative Example were added in portions to a reactor operated at a pressure of 3 bar corresponding to 110° C. After the reaction conditions had been adjusted, the slurry was allowed to age for 40 hours using a standard agitator running at a peripheral velocity of 1.6 m/s corresponding to an agitator speed of 500 r.p.m.
The crystallite sizes measured as described in the Comparative Example were 15.3 nm (120 reflex) and 15.3 nm (020 reflex). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 67 m2/g.
EXAMPLE 4
500 grams of the alumina slurry (pH 9) containing 10 to 11 wt. % Al2O3 as defined in the Comparative Example were added in portions to a reactor operated at a pressure of 3 bar corresponding to 110° C. After the reaction conditions had been adjusted, the slurry was allowed to age for 60 hours using a standard agitator running at a peripheral velocity of 1.6 m/s corresponding to an agitator speed of 500 r.p.m.
The crystallite sizes measured as described in the Comparative Example were 16.1 nm (120 reflex) and 16.5 nm (020 reflex). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 72 m2/g.
EXAMPLE 5
600 grams of the alumina slurry (pH 9) containing 10 to 11 wt. % Al2O3 as defined in the Comparative Example were added to 50 grams of a 20% aqueous tetrene solution and boiled under reflux for 68 hours. 300 grams of H2O were added to this mixture at one-hour intervals. The mixture was diluted with 200 grams of H2O und spray dried.
The crystallite sizes measured as described in the Comparative Example were 14.4 nm (120 reflex) and 14.6 nm (020 reflex). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 81 m2/g.
EXAMPLE 6
300 grams of a 6.02% aluminium-tri-n-hexanolate solution in n-hexanol were added at 90° C. to 360 grams of a 5% aqueous tetrene solution. This mixture was agitated at 90° C. for 30 minutes. The hexanol was removed from the reaction mixture by azeotropic distillation. The residue then was agitated at 90° C. for 24 hours. H2O was added in 100-gram portions after 1 hour, 2 hours, and 3 hours, respectively. The reaction mixture was spray dried.
The crystallite sizes measured as described in the Comparative Example were 11.0 nm (120 reflex) and 11.8 nm (020 reflex). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 76 m2/g.
EXAMPLE 7
300 grams of a 6.02% aluminium-tri-n-hexanolate solution in n-hexanol were added at 90° C. to 360 grams of a 5% aqueous tetrene solution. This mixture was agitated at 90° C. for 30 minutes. The hexanol was removed from the reaction mixture by azeotropic distillation. The residue then was agitated at 90° C. for 68 hours. H2O was added in 100-gram portions after 1 hour, 2 hours, and 3 hours, respectively. The reaction mixture was spray dried.
The crystallite sizes measured as described in the Comparative Example were 12.6 nm (120 reflex) and 16.4 nm (020 reflex). After thermal treatment at 1,200° C. for 3 hours the specific surface was found to be 79 m2/g.







TABLE 1







X-Ray Powder Diffraction Pattern of Example 1 (Comparative


Example) with Significant Quantity of Alpha-Al2O3















d-Value
d-Value
T-Width
Height
Backgr.
Rel.



d-Value [°2θ]
α1 [Å]
α2 [Å]
[°2θ]
[counts]
[counts]
Int. [%]
Signific.





16.205
5.46527
5.47872
0.480
19
29
4.1
1.56


19.550
4.53706
4.54822
0.480
45
27
9.5
2.53


21.850
4.06440
4.07439
0.480
9
24
1.9
0.80


25.560
3.48224
3.49081
0.180
276
30
58.5
7.44


31.230
2.86174
2.86878
0.200
286
41
60.7
2.47


32.695
2.73678
2.74351
0.120
441
37
93.7
1.23


32.825
2.72624
2.73294
0.080
441
37
93.7
0.97


35.135
2.55211
2.55838
0.140
449
35
95.4
4.34


36.660
2.44937
2.45539
0.200
313
34
66.5
1.41


37.695
2.38446
2.39032
0.140
185
31
39.3
2.48


38.910
2.31275
2.31844
0.120
266
30
56.4
0.91


39.855
2.26007
2.26563
0.160
169
30
35.9
0.92


41.715
2.16349
2.16881
0.480
21
27
4.5
1.69


43.305
2.08767
2.09280
0.160
396
27
84.1
6.77


44.785
2.02205
2.02703
0.320
282
26
59.9
9.47


45.605
1.98758
1.99247
0.360
137
25
29.1
3.48


46.515
1.95080
1.95560
0.240
90
24
19.2
2.18


47.630
1.90770
1.91239
0.120
185
23
39.3
1.31


50.680
1.79981
1.80424
0.320
77
22
16.4
4.82


51.520
1.77242
1.77678
0.320
22
22
4.7
0.78


52.450
1.74317
1.74745
0.100
154
22
32.7
1.18


57.415
1.60366
1.60761
0.160
317
25
67.3
6.46


58.730
1.57085
1.57471
0.240
26
25
5.5
0.76


59.820
1.54480
1.54861
0.120
114
25
24.3
1.93


61.240
1.51234
1.51606
0.160
74
25
15.7
1.05


62.295
1.48924
1.49291
0.400
71
24
15.0
2.02


63.850
1.45667
1.46025
0.240
137
24
29.1
3.28


64.165
1.45028
1.45385
0.120
98
24
20.8
1.06


65.450
1.42488
1.42838
0.320
59
23
12.6
1.06


66.475
1.40537
1.40883
0.100
324
24
68.8
0.85


67.395
1.38841
1.39182
0.440
471
23
100.0
18.43


68.155
1.37477
1.37815
0.100
190
23
40.4
0.92


72.900
1.29654
1.29973
0.320
41
21
8.7
1.33


73.700
1.28443
1.28759
0.400
48
21
10.1
2.55


75.460
1.25878
1.26188
0.560
28
19
6.0
4.30


76.800
1.24012
1.24317
0.160
58
18
12.3
1.06











Measurement parameters:
Start angle [°2θ]: 5.010; end angle [°2θ]: 79.990;



start d-value [Å]: 17.62435; end d-value [Å]: 1.19850;



anode material: Cu;



α1 wave length [Å]: 1.54060; α2 wave length [Å]: 1.54439













TABLE 2







X-Ray Powder Diffraction Pattern of Example 2


(Al2O3 with >98% Theta Phase)















d-Value
d-Value
T-Width
Height
Backgr.
Rel.



d-Value [°2θ]
α1 [Å]
α2 [Å]
[°2θ]
[counts]
[counts]
Int. [%]
Signific.

















16.240
5.45357
5.46699
0.400
40
28
6.6
1.55


19.495
4.54974
4.56093
0.400
56
30
9.4
1.21


25.230
3.52704
3.53571
0.800
11
28
1.8
1.26


31.130
2.87070
2.87777
0.320
292
42
48.7
4.94


32.685
2.73759
2.74433
0.180
600
42
100.0
3.57


32.790
2.72907
2.73578
0.060
562
42
93.6
0.80


34.845
2.57268
2.57901
0.320
102
41
17.0
2.05


36.635
2.45098
2.45701
0.320
372
40
62.1
5.21


38.820
2.31791
2.32361
0.280
266
41
44.3
4.26


39.890
2.25816
2.26372
0.240
196
40
32.7
1.80


43.295
2.08813
2.09326
0.320
15
29
2.5
1.01


44.720
2.02484
2.02982
0.360
361
28
60.1
12.86


46.530
1.95020
1.95500
0.480
59
27
9.9
0.93


47.585
1.90940
1.91410
0.280
196
25
32.7
5.21


50.585
1.80297
1.80741
0.240
85
24
14.1
2.69


51.470
1.77403
1.77839
0.320
31
23
5.2
1.18


52.455
1.74301
1.74730
0.320
22
23
3.7
1.03


56.580
1.62533
1.62933
0.640
18
23
2.9
0.99


57.365
1.60494
1.60889
0.320
20
24
3.4
0.75


58.755
1.57024
1.57410
0.240
37
24
6.2
2.28


59.850
1.54410
1.54790
0.200
139
24
23.2
1.67


62.310
1.48892
1.49258
0.400
100
24
16.7
2.83


63.925
1.45514
1.45872
0.400
164
25
27.3
10.08


65.355
1.42672
1.43023
0.480
69
26
11.5
2.58


66.450
1.40584
1.40930
0.240
228
25
38.0
2.47


67.395
1.38841
1.39182
0.600
524
26
87.4
39.85


72.845
1.29738
1.30057
0.480
50
24
8.4
2.92


73.715
1.28420
1.28736
0.400
64
23
10.7
3.36


75.295
1.26113
1.26423
0.400
27
20
4.5
1.56


77.320
1.23308
1.23611
0.960
15
18
2.5
3.48





Measurement parameters as specified in Table 1.













TABLE 3







X-Ray Powder Diffraction Pattern of an Aluminium Oxide of this


Invention in the Delta Phase















d-Value
d-Value
T-Width
Height
Backgr.
Rel.



d-Value [°2θ]
α1 [Å]
α2 [Å]
[°2θ]
[counts]
[counts]
Int. [%]
Signific.

















19.605
4.52446
4.53559
0.480
21
49
6.2
0.82


32.855
2.72382
2.73052
0.560
69
139
20.3
2.95


36.865
2.43621
2.44221
0.320
114
132
33.8
0.95


39.570
2.27568
2.28128
0.880
117
90
34.5
10.25


45.475
1.99296
1.99787
0.560
272
58
80.4
7.14


46.385
1.95596
1.96077
0.480
146
56
43.2
2.24


50.865
1.79370
1.79811
0.800
10
40
3.0
1.35


58.990
1.56455
1.56839
0.140
11
61
3.2
0.85


59.985
1.54095
1.54474
0.800
18
74
5.5
1.38


66.470
1.40547
1.40892
0.560
279
83
82.4
3.34


67.220
1.39160
1.39502
0.240
339
76
100.0
0.99





Measurement parameters as specified in Table 1.

## Claims

1. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina having a greater than 99% atomic purity of hydrogen, aluminum and oxygen atoms and a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 1.5 nm and
(2) oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, boron and mixtures thereof.

2. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina having a greater than 99% atomic purity of hydrogen, aluminum and oxygen atoms and a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 0.5 nm and
(2) oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, and mixtures thereof.

3. The alumina according to any one of claim 1 or 2, characterized in that the crystallite size determined on the 020 reflex is from greater than 10 to 50 nm.

4. The alumina according to any one of claim 1 or 2, characterized in that the alumina is obtained from the hydrolysis of aluminium alkoxides.

5. The alumina according to claim 1, characterized in that the alumina comprises said oxides or oxide hydrates in an amount of from 0.1 to 5 wt. %, referring to Al2O3.

6. A catalyst or catalyst support comprising an aluminium oxide composition prepared from the crystalline boehmitic alumina or pseudo boehmitic alumina comprising oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, boron and mixtures thereof in an amount of from 0.1 to 5 wt. %, referring to Al2O3 according to any one of claims 1 or 2 by thermal treatment, wherein said thermal treatment comprises calcination at a temperature of from 800 to 1500° C. for at least 0.5 hour, wherein the boehmitic alumina or pseudo boehmitic alumina has a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 1.5 nm and wherein the boehmite is produced from the hydrolysis of aluminum alkoxides.

7. The composition of claim 6, characterized in that the aluminium oxide is present in the theta or delta phase.

8. The catalyst or catalyst support according to claim 6, characterized in that after thermal treatment by calcination at 1,200° C. for 3 hours the aluminium oxide has a surface of greater than 60 m2/g.

9. The catalyst or catalyst support according to claim 6, characterized in that the aluminium oxide has pore volumes of greater than 0.6 cm3/g, determined by the mercury penetration method in the pore radius range of from 1.8 to 100 nm.

10. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina having an atomic purity of greater than 99% of hydrogen, aluminum, and oxygen atoms, said alumina prepared by hydrolysis of aluminum alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of lanthanum and a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 1.5 nm and
(2) oxides or oxide hydrates of lanthanum in an amount of from 0.1 to 5 wt. %, referring to Al2O3.

11. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina prepared by hydrolysis of aluminum alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, boron and mixtures thereof and having a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 1.5 nm and (2) oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, and/or boron and mixtures thereof.

12. A composition comprising (1) a high purity crystalline boehmitic alumina or pseudo boehmitic alumina prepared by hydrolysis of aluminum alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, and mixtures thereof and having a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 0.5 nm and (2) oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, and mixtures thereof.

13. The alumina according to any one of claim 11 or 12, characterized in that the crystallite size determined on the 020 reflex is from greater than 10 to 50 nm.

14. The alumina according to claim 11, characterized in that the alumina comprises said oxides or oxide hydrates an amount of from 0.1 to 5 wt. % referring to Al2O3.

15. A catalyst or catalyst support comprising an aluminum oxide composition prepared from the crystalline boehmitic alumina or pseudo boehmitic alumina comprising metallic oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, boron and mixtures thereof in an amount of from 0.1 to 5 wt %, referring to Al2O3 according to any one of claim 11 or 12 by thermal treatment, wherein said thermal treatment comprises calcination at a temperature of from 800 to 1500° C. for at least 0.5 hour.

16. The composition of claim 15, characterized in that the aluminum oxide is present in the theta or delta phase.

17. The catalyst or catalyst support according to claim 16, characterized in that after thermal treatment by calcination at 1,200° C. for 3 hours the aluminum oxide has a surface of greater than 60 m2/g.

18. The catalyst or catalyst support according to claim 16, characterized in that the aluminum oxide has pore volumes of greater than 0.6 cm3/g, determined by the mercury penetration method in the pore radius range of from 1.8 to 100 nm.

19. A composition comprising a high purity crystalline boehmitic alumina or pseudo boehmitic alumina prepared from the hydrolysis of aluminum alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of lanthanum and having a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex by 1.5 nm and comprising oxides or oxide hydrates of lanthanum.

20. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina having a greater than 99% atomic purity of hydrogen, aluminum and oxygen atoms, said alumina prepared by the hydrolysis of aluminium alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, boron and mixtures thereof and a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 1.5 nm and
(2) oxides or oxide hydrates of one selected from the group consisting of zirconium, titanium, lanthanum, boron and mixtures thereof.

21. A composition comprising:
(1) a crystalline boehmitic alumina or pseudo boehmitic alumina having a greater than 99% atomic purity of hydrogen, aluminum and oxygen atoms, said alumina prepared by the hydrolysis of aluminium alkoxides and hydrothermally aged in the presence of water and oxides or oxide hydrates of zirconium, titanium, lanthanum, and mixtures thereof and a crystallite size that, determined on the 020 reflex in nm, is larger than the measured crystallite size determined on the 120 reflex reduced by 0.5 nm and
(2) oxides or oxide hydrates of zirconium, titanium, lanthanum, and mixtures thereof.