The Ultra-Violet Absorption Spectrum of Carbon Suboxide Gas

Abstract

The carbon suboxide used in this investigation was prepared by the diacetyl tartaric anhydride method (1), and was kindly supplied by Dr. W. E. Vaughn of this laboratory. The material was purified by four vacuum distillations and may have contained a trace of acetic acid as impurity which, however, would not have been disturbing in the region investigated. The carbon suboxide gas was contained in a quartz absorption cell 15 cm. in length, provided with plane windows and a side arm containing an excess of the material in liquid form. By controlling the temperature of the latter the gas pressure in the cell could be regulated. The absorption cell itself was kept at room temperature, which was about 21°C. The carbon suboxide apparently kept well if sealed in perfectly clean quartz vessels, especially if maintained at low temperatures, but after long exposure to ultra-violet radiation a white deposit collected on the windows of the cell. This was probably a polymerized form of the suboxide and it quickly changed over to a reddish orange form if gently heated.