Table 1. iV,V-'s(2-CYANOETHYL) 30-60 MESH FIREBRICK AT 80FORMAMIDE 20 PER CENT ON C. AT 75 ML./MIN. HELIUM Retention Retentiontime (min.) time (min.) Class relative Class relativeto air to air Hydrocarbons Esters (continued)n-Pentane 0-25 w-Butyl acetate 12-5 n-Hexane 0-5 Isopropyl acetate 4-5n-Decane 2-75 Tertiary butyl 2,2,4-Trimethyl acetate 3-5pentane 1-0 Methyl acrylate 7-5 CtycZo-hexane 0-75 Ethyl acrylate 8-0Benzene 5-0 Methyl methacrylate 8-5 Toluene 8-0 Ethyl methacrylate 9-25Ethyl benzene 12-5 Isopropyl acrylate 7-0 Styrene 28-5 Sec. butyl acrylate 10-5Esters Halogenated Compounds Methyl acetate 5-0 Methylene chloride 4-5Ethyl acetate 5-5 Chloroform 6"0 n-Propyl acetate 8-0 Carbon tetrachloride 2-0This communication deals with a liquid phase developed in these laboratories which has approximately the selectivity of p,p'-oxydipropionitrile but has considerably less vapour pressure. This new phase, developed with the assistance of Dr. N. Bortnick, has been in use for approximately two years. The compound Ar,2V/-6s-(2-cyanoethyl) formamide was synthesized in these laboratories and successfully used as a liquid phase for the separation of isomeric esters and hydrocarbons. (3,P'-Oxydipropionitrile has a maximum usable temperature somewhere below 80 C., at which point it starts to deteriorate very rapidly. N,N-bis(2-cyano-ethyl) formamide, on the other hand, is stable to at least 125C.Typical separations of various classes of compounds are listed in Table 1. These separations were carried out on conventional gas chromatographic equipment under as constant conditions as possible. Detailed conditions of the operating parameters are not included, since these will be set by the investigator for each particular problem. Table 1 includes only a few of the compounds separated with this substrate. Columns using this liquid at 85 C. have been in constant use for more than a year with no apparent change in retention time.