Only Touch solution preparation

Acetyl azide has been prepared only in solution ". Propionyl azide is a colourless liquid of pungent odour, the inhalation of which causes severe headaches. Higher fatty acid azides have been obtained by distillation at 0° and 0-5 mm Hg and their infrared spectra measured neat (Table 1). rv-Hexanoyl azxde shows i.r. bands at 2130 and 1720 cm in cyclohexane solution. A number of more complex alkanoyl azides have also been prepared in solution while the azide of tetra-acetyl-D-arabonic acid was isolated crystalline (m.p. 105-6° dec.) ". An example of a more exotic acyl azide is 2,3-diphenyl-cycloprop-2-ene-1-carbonyl azide . The diazide of oxalic acid was isolated crystalline (from CCI4) but exploded when touched with a spatula . Succinamoyl azidea crystalline substance with a decomposition point of 70-80°, undergoes slow Curtius rearrangement already at room temperature, just as the azides of monocarboxylic acids do. 

Preparation of Hydrofluoric Acid. Put 5 g of fluorite and 1 g of gypsum into a Teflon (polytetrafluoroethylene), lead, or copper test tube (why is gypsum added ). Pour 5 ml of a 96% sulphuric acid solution over the mixture, tightly close the test tube with a rubber stopper provided with a Teflon, lead, or copper gas-discharge tube. Lower the end of this tube into a Teflon, lead, copper, or paraffin-coated glass beaker containing 10 ml of water so that it only slightly touches the surface of the water (why ). Put an asbestos sheet between the beaker and the Teflon test tube. To speed up the reaction, it is recommended to immerse the Teflon test tube into a beaker with hot water. Why must the test tube not be heated directly by the flame of a burner ... 

B) Preparation of Cyclopentanone (M.). Arrange a 250-ml distilling flask for downward distillation. The thermometer is so placed that it nearly touches the bottom of the distilling flask. Place in the flask 25 g of finely pulverized adipic acid and 3 g of finely ground barium hydroxide. Shake the flask so as to mix the contents, then insert the thermometer, and connect the flask with an air condenser. By means of a free flame heat the flask to 285-290°. The burner is moved to and fro so that the heat is directed at all sides of the flask. When the mixture has melted, adjust the flame so that the temperature remains at about 290°. If the temperature is allowed to rise above 295°, adipic acid distills over and the condenser becomes clogged. Continue the distillation until only a small residue remains in the flask. Transfer the distillate into a separatory funnel and add 10 ml of saturated salt solution and 10 ml of 5 per cent sodium bicarbonate solution. Shake cautiously and remove the ketone layer. Dry with 2-3 g of calcium chloride and distill. The yield is 14-18 g. 

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