A Cyclic Tetramer of Chloral

Abstract

TREATMENT of chloral or its hydrate with concentrated sulphuric acid yields a number of polymeric materials which were identified by Chattaway and Kellett¹ and studied by Novak and Whalley². From the mixture obtained in this Laboratory by treating some 300–400 gm. of chloral hydrate, about 2 gm. (0.5 per cent) of a new polymeric compound was isolated as a white crystalline solid (m.p. 219–220° corr.). It crystallized from absolute ethanol as short needles slightly less soluble in this solvent than chloralide or α-parachloral. The compound is very soluble in acetone, pyridine and ether; moderately soluble in boiling ethanol; slightly soluble in carbon disulphide, carbon tetrachloride and cold ethanol and insoluble in water. Boiling with an aqueous ethanol–20 per cent sodium hydroxide solution liberates chloroform and formic acid. Further work gave the following results: Analysis, calculated for (CCl₃–CHO)_n: C, 16.28; H, 0.68; Cl, 72.17. Found: C, 16.43; H, 0.73; Cl, 71.78. Molecular weight (Rast), calculated for (CCl₃–CHO)₄, 589.5. Found: 614, 616, 571 (average 600.3). Infra-red spectrum: the compound was examined in ‘Nujol’ mull (0.025 mm.) and in saturated (18° C.) carbon tetrachloride and carbon disulphide solutions (1 mm.), on a model 137 ‘Infracord’ spectrophotometer (with sodium chloride prism). The bands observed are recorded in Table 1.