n8 PRACTICAL ORGANIC CHEMISTRY dissolved and the evolution of carbon dioxide has ceased, fit a reflux air-condenser to the flask and boil the solution gently for 30 minutes, when the dehydration of the ammonium acetate will be complete. Now remove the condenser and fit a fractionating column to the flask: for this purpose a 4-pear column may be used, but far better results are obtained if a column of the type shown in Fig. U(B) (p. 26), in which the glass sections them-selves occupy a height of about 12 cm., is used. Fit a 360° thermometer in the column, and fit the air-condenser to the side-arm for distillation. Now distil the liquid through the column very slowly (to give about i drop of distillate every 3 seconds) until the temperature reaches 170°: it is very important that this operation should be carried out slowly in order to distil over as much water and excess of acetic acid as possible, and so to leave almost pure acetamide in the flask. Without delay, pour the hot molten acetamide into a small (50 ml.) distilling-flask, and attach
This is the end of the preview. Sign up
access the rest of the document.