Alumina, basic Woelm

Diehloromethane was purified by percolation through Woelm activity grade 1 basic alumina and stored under nitrogen. 

Weakly basic alumina (200-300 raesh] for column chromatography is used. The checkers used Alumina Woelm-B, Akt. 1. 

Woelm Alumina Neutral, acidic or basic porous alumina... 

The solid chosen for their work on reaction (XLVIII) was alumina whose surface possesses several types of Bronsted and Lewis acidic and basic functional groups (-Al+-, -OHa+, -O - H, -0 , and defect sites) [175, 219] which could be potential catalysts for the mutarotation of glucose. Woelm... 

The application frequency of alumina is less than that of silica. Three essentially different types of alumina exist on the basis of their functional groups acid, basic and neutral alumina. For instance, Woelm Co. offers basic, neutral and acidic alumina with the pH values (of their suspension) of 9, 7.5 and 4, respectively. Alumina is prepared from aluminium hydroxide by a calcination procedure at moderate temperature. Alumina... 

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

A Sciirlc gnuip I uunil Ihiit the 5((-liydioxy-6 B-melhyl-3-ketosleroid (I) on dehydration by refluxing with florisil in benzene is converted in good yield into the 3-keto-A -6/3-methyl steroid (2). When basic alumina (Woelm-1) was used as... 

Methyl 4-0-methyl-2,3,6-tri-0-(methanesulfonyl)-a-D-mannopyranoside and Woelm basic alumina in benzene kept 41 hrs. at 50° methyl 4-0-methyl-2,3-di-0-(methanesulfonyl)-a-D-mannopyranoside. Y 98%. - Also ethers in the presence of alcohols, and with neutral alumina s. F. W. Parrish, R. C. Chalk, and L. Long, Jr., J. Org. Chem. 33, 3165 (1968). 

CAUTION Upon standing, ethers may form peroxides. Peroxides are very explosive. To test for the presence of these substances, use starch-iodide paper that has been moistened with 6 M HQ. Peroxides cause the paper to turn blue. To remove peroxides from ethers, pass the material through a short column of highly activated alumina (Woelm basic alumina, activity grade 1). ° Always retest for peroxides before using the ether. 

---