. The Biochemical journal, 1918. Biochemistry. 74 G. W. ELLIS AND J. A. GARDNER Experimental. Preparation of ^-cholestanol. The reduction of cholesterol to ^-cholestanol was first carried out by Willstatter and Meyer [1908] by the use of hydrogen and platinum black in ethereal suspension. The exact technique of this method has been somewhat modified by us and with such good results that it may therefore be described. The dry pure ether used was prepared from the commercial product by treatment in the cold with about 10 % of its weight of a finely powdered mixture of dry potassium hydroxide and
. The Biochemical journal, 1918. Biochemistry. 74 G. W. ELLIS AND J. A. GARDNER Experimental. Preparation of ^-cholestanol. The reduction of cholesterol to ^-cholestanol was first carried out by Willstatter and Meyer [1908] by the use of hydrogen and platinum black in ethereal suspension. The exact technique of this method has been somewhat modified by us and with such good results that it may therefore be described. The dry pure ether used was prepared from the commercial product by treatment in the cold with about 10 % of its weight of a finely powdered mixture of dry potassium hydroxide and potas- sium permanganate in the proportion of about four parts of potash to one of permanganate. The mixture was occasionally shaken for a period of 24-28 hours and after settling the ether was decanted and distilled over phosphorus pentoxide. The hydrogen, which it is essential should be pure and dry, was prepared electrolytically, the electrolyte employed being a saturated solution of barium hydroxide. The cathode was a silver coil and the anode a platinum coil. The general arrangement of the voltameter is shown in the accompanying The Preparation of Dihydrocholesterol. The hydrogen passed through a calcium chloride tower, through phos- phorus pentoxide and then through dry ether. The latter served the purpose of arresting any traces of phosphorus pentoxide and of making up for loss of ether from the cholesterol solution by its own evaporation. The ethereal solution of cholesterol, which should be not more than three-fourths saturated, contained about 8 grams of platinum black to 400 cc. of the solution. The platinum black was prepared according to the method of Loew [1890]. It was found very necessary to keep the solution of cholesterol continually and vigorously shaken, in order that the heavy platinum black should be in. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and app
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