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Aluminum oxide for chromatography is being used in the laboratory and in industrial production:
- For preparative column chromatographic separations
- As a support material in analytical chromatographic columns
- On industrial scale for the removal of small amounts of undesired components, e.g. side reaction products from mother liquors, water from non polar solvents, etc.
Properties
Aluminum oxide for chromatography, is a white, fine-grained powder. Its chromatographic characteristics are determined by its specific (internal) surface area measured by the BET method, its mean pore diameter, and its pore volume, the latter two being in relation to the specific surface area. A further characteristic is its Brockmann activity which is measured by an accepted test procedure. Aluminum oxide of the highest Brockmann activity (I) can be deactivated to lower activities II to V by adding controlled amounts of water (see table).
Activated aluminum oxide is manufactured by mild calcination of aluminum hydroxide (boehmite). Due to its trace amounts of sodium hydroxide (Al-O-Na groups) it has a basic reaction.
CAMAG also offers neutral (pH 7.0), weakly acidic (pH 6.0) and acidic grades (pH 4.5) which are obtained by the addition of precisely dosed amounts of HCl gas. An example of grades and their corresponding data is supplied below.
| Grade |
5016-A basic |
507-C neutral |
504-C acidic |
| pH of a 5 % aqueous suspension (stirred) |
9.5 ± 0.5 |
7.0 ± 0.5 |
4.5 ± 0.5 |
| Specific surface [m2/g] |
150 ± 10 % |
150 ± 10 % |
150 ± 10 % |
| Brockmann activity |
any |
any |
any |
| Mean pore diameter [Å] |
60 |
60 |
60 |
| Pore volume [mL/g] |
~ 0.25 |
~ 0.25 |
~ 0.25 |
| Cl‘ [mval/g] |
nil |
0.03 |
0.14 |
| Fe2O3 [%] |
0.01 - 0.03 |
0.01 - 0.03 |
0.01 - 0.03 |
| Na2O [%] |
0.25 - 0.4 |
0.25 - 0.4 |
0.25 - 0.4 |
| Bulk density [g/L] |
~ 920 |
~ 920 |
~ 920 |
| Safety Data Sheet |
5016A.pdf |
507C.pdf |
504C.pdf |
New Granulometry starting January 2006
| (all grades): |
> 200 µm |
0 - 1 % |
|
160 - 200 µm |
1 - 2 % |
|
100 - 160 µm |
47 - 70 % |
|
71 - 100 µm |
25 - 35 % |
|
40 - 71 µm |
3 - 15 % |
|
< 40 µm |
0 - 3 % |
| Available on request: |
> 71 µm |
0 - 2 % |
|
40 - 71 µm |
65 - 80 % |
|
< 40 µm |
20 - 35 % |
Packing
CAMAG aluminum oxide for chromatography is supplied in fiber drums lined with polyethylene bags of 50 kg net. Other packing on request.
Laboratory quantities are available in polyethylene bottles of 1 kg or 5 kg.
Warning: Aluminum oxide for chromatography adsorbs water from the air. Therefore it must be stored in air-tight containers as otherwise its Brockmann activity can change.
Production
Activated aluminum oxide is produced by mild calcination of aluminum hydroxide (aluminum trihydrate, boehmite) which is an intermediate in the industrial production of aluminum from Bauxite. It is precipitated (crystallized) from a sodium aluminate solution. By heating the aluminum hydroxide so obtained at temperatures between 450 and 500°C 33 % constitutional water is removed whereby the crystal structure of the boehmite remains intact. The chromatographic activity results from this fact.
CAMAG supplies two basic grades: 4516A and 5016A where the two first digits stand for the temperature used. From these two basic grades, the neutral and acidic grades are manufactured.
Prices
Please submit your inquiry to sales@camag.com or fax to ++41 61 461 07 02
Remarks
If aluminum hydroxide is calcinated at temperatures above 1000°C, inactive alpha-aluminum oxide is formed which is used for the industrial production of aluminum by fused salt electrolysis
Activated alumina (alumina gel) in coarse grain or chunky form, which is used for industrial gas drying, is produced in a different way, i.e. by precipitation from an acidic aluminum salt solution. Such material is not available from CAMAG.
| Brockmann activity |
Addition of water [%] |
| I |
0 |
| II |
3 |
| III |
6 |
| IV |
10 |
| V |
15 |
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