Alumina, chromatographic grading

Aluminas. Non-activated aluminas (chromatographic grade) are basic supports versus rather acidic carbonic acids (pKa < 15), able to abstract hydrogen and to subsequently react. When calcinated up to 400-600 C, they behave as Lewis acids due to liberation of the surface hydroxyl groups. 

Prepare an alumina column as follows Mix 20 g of alumina (chromatographic grade) with sufficient 70 per cent ethanol to form a thin slurry and transfer to a glass tube 1 in. in diameter fitted with a tap at the lower end and which has previously been plugged with glass wool. Allow the alumina to settle and drain the tube until the level of liquid is just above the surface of the alumina. Do not allow the column to become dry. 

Impurities resulting from storage can be removed by passage through chromatographic grade alumina. Furfural can be separated from impurities other than carbonyl compounds by the bisulfite addition compound. The aldehyde is steam volatile. 

The resulting dry LSD base is chromatographed on basic alumina (activity grade 1) as previously described. The blue band is collected as before, evaporated and converted into the tartrate salt. The iso-LSD band may be collected and saved for further re-cycling. 

Dimethylsulfoxide is purified by filtration through a 2 x 25 cm chromatographic column filled with alumina (activated grade I, neutral, 150 mesh), under a nitrogen atmosphere. This procedure of purification of the solvent is crucial to obtain the indicated yield, since on use of distilled or commercially available anhydrous dimethylsulfoxide, extensive decomposition takes place. 

Woelm 200 acidic chromatographic alumina (activity grade super 1). Woelm 200 basic chromatographic alumina (activity grade super 1). 

Vz grams of the residue were dissolved in 10 ml of benzene, and the solution was passed over a chromatographic adsorption column containing 50 grams of alumina (Alcoa activated alumina. Grade F-20) which had previousiy been shaken for about 20 minutes with a mixture of 100 ml of benzene containing 1.5 ml of 10% acetic acid. 

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