hexylene glycol 1 2 butanediol polyethylene glycols 200 and 300 anisole diisobutyl ketone n butyl acetate propoxypropanol hexyl alcohol undecyl alcohol isodecanol alpha methyl benzyl alcohol cyclododecanol diisobutyl carbinol 2 octanol methyl isoamyl ketone 3 heptanone diethylene glycol diethyl ether 3 octanone isophorone 2 hydroxyacetophenone 2 undecanone mesityl oxide benzyl benzoate ethylene glycol diacetate ethyl salicylate 3 hexanone ethylene glycol phenyl ether isobutyl butyrate ethylene glycol butyl ether ethyl butyrate methyl caproate amyl propionate and ethyl n valerate the compounds which bring out the t butyl alcohol was overhead product are 1 3 butanediol 1 4 butanediol dipropylene glycol triethylene glycol 2 methyl 1 3 propanediol diethylene glycol polyethylene glycol 400 tetraethylene glycol methyl benzoate dimethyl sulfoxide dimethyl formamide dimethyl phthalate and dimethyl adipate table 4 lists a number of compounds that proved to be ineffective as extractive distillation agents in the separation of t butyl alcohol from water three of the agents whose relative volatility had been determined in the vapor liquid equilibrium still were then evaluated in a glass perforated plate rectification column possessing 7 3 theoretical plates and the results listed in table 5 vinyl n butyl ether was evaluated in the azeotropic distillation mode and gave a relative volatility of 1 50 1 3 butanediol and triethylene glycol were evaluated in the extractive distillation mode and yielded relative volatilities of 1 178 and 1.