The structure and activation of the phosgene molecule. Part III.—A study of the ultra-violet absorption spectrum of phosgene vapour

Abstract

The phosgene used was Kahlbaum’s purest and was first fractionally distilled. Two double-necked bulbs, each of about 50 c. c. capacity, were sealed together with a tap between. The free limb of the second bulb was also provided with a tap and connected to two Langmuir pumps in series. The phosgene was cooled in solid carbon dioxide and ether and about 10 c. c. was transferred to the first bulb which was similarly cooled and which was then sealed off. The second bulb was evacuated, put in connection with the first bulb until full of vapour and then evacuated again. This was repeated several times until about 2 or 3 c. c. of phosgene had disappeared. The second bulb was then cooled with solid carbon dioxide and ether and the first bulb allowed to warm slowly until about a third of the phosgene remaining had distilled over. The second bulb was then sealed off from the first and was connected at D to the absorption apparatus shown in fig. 2. The absorption tube itself consists of a glass tube TT fitted by means of ground joints with two end pieces EE for convenience in cleaning. The total length is 100 cm. The end pieces are provided with polished quartz windows QQ fitted on with cement. The tube is in connection with two bulbs; a small one S of about 20 c. c. capacity and a large one L of about 500 c. c. These bulbs are connected to one another and to a mercury manometer M by which the pressure in the tube may be registered. The storage bulb G is attached by means of a mercury sealed joint J.