Woelm alumina

Distd, then repeatedly fractionally crystd by partial freezing. Immediately before use, the material was passed through a column containing Woelm silica gel (activity I) and Woelm alumina (neutral) in separate layers. 

Trans addition of methoxide ion to K-region as well as non-K-region arene oxides is achieved under mild conditions (25°C in ether) in good yield, using a Woelm alumina catalyst.149 This reaction is discussed in Section V,B,4. 

The dimer-rich fractions were adsorbed on 30 parts of Woelm alumina, activity grade IV (i.e., alumina containing 10% water) and eluted first with mixtures of chloroform and cyclohexane and on a second pass with benzene and cyclohexane. Occasionally, acetone-cyclohexane mixtures were used for better separation of alcohols and dimers and nylon powder chromatography for ultimate purification. Even at a 30 1 (alumina lignin) weight... 

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

Carbon tetrachloride (spectral grade) was passed through a thick layer of Woelm alumina (neutral). 1,1,2,2-Tetrachloroethane was used as a cosolvent to aid 1n the dissolution of the starting sugar derivative. In other instances carbon tetrachloride was the solvent. 

Chloral is used as the hydrogen acceptor in the quantitative oxidation of cyclobutanol to cyclobutanone. The reaction takes place on Woelm alumina at room temperature in carbon tetrachloride after 24 h [95S]. Under similar conditions, primary alcohols are oxidized in preference to secondary alcohols [959]. 

The first batch of extract was dissolved in a small volume of methylene chloride and subjected to gradient chromatography on alumina. Woelm alumina was washed with methylene chloride several times and then activated at about 95 °C for several hours. A 26-ml column (9 mm id) was prepared with a slurry of this alumina in pentane, and 122 fractions were eluted with a succession of solvents as follows pentane... 

The oxidations are all rapid, and the decrease in yield is due to decreasing rate of addition in the order (2)>(5)>(7). In experiments on a 10-mmole scale the reaction mixture was treated with 7 g. of Woelm neutral alumina and the whole cvapoi utcd to dryness at reduced pressure. T he resulting solid was packed on top of a chromatographic column of. 5(1 g. of Woelm alumina deactivated by 10% of water, and the chromatogram was then develuped (( ( U C H CTy). 

A and A are two different batches of Woelm alumina with different OH contents. B are samples of A alumina calcinated in air at 600°C during 2 210 hr. 

Barrett and Buchi3a dehydrated the epimeric alcohol mixture (1) by grinding 6.6 g. with 21 g. of neutral Woelm alumina (activity I) mixed with 2% w/v of anhy-... 

Dimethyl-2,4-hexadiene [764-13-6] M 110.2, f 14.5 , h 132-134 , d f 0.773, n 1.4796. Distil it, then repeatedly fractionally crystallise it by partial freezing. Immediately before use, the diene is passed through a colunm containing Woelm silica gel (activity I) and Woelm alumina (neutral) in separate layers. [Beilstein 1IV 1043 ]... 

Scheme 36. Reagents a, K2Cr207, c H2SO4, aq. acetone b, Woelm alumina, CICH2CH2CI c, 9-BBN, THF d. NaOH, H2O2.

NPE, E = 9 isolation of homologs up to E = 22 Reversed-phase media Woelm alumina (acid grade), 1.0 mm 2-Butanone Modified Dragendorff reagent 106... 

---