An Improved Microbulb Vacuum Distillation Apparatus The Kugelrohr and its several modifications have heen described in literature-s Use of a %bulb c Kugelrohr, with the middle bulb (receiver) cooled VAWUH by ice-water, for vacuum distillation of monoterpenes (5-50 mg) resulted in much loss. The impnrved apparatus (figure) where a wide-necked ampoule (receiver) is fused to the middle bulb and chilled in freezing mixture obviates this loss. This is essentially an improved version of an earlier modified Kugelrohr.' O~LBIITU The liquid is transferred with a fine capillary dropper down the 120' bend (apparatus vertical) using 2-3 p drops of dry EtzO to transfer the last traces and stripping the Et20(40PC)/100 mml2-3 min-a pumice bit or a tiny boiling reed helps smooth boiling. T h e unit is connected to the desired vacuum and gradually heated. The b.p. may be expressed within 2 - S T range of the bath temperature st which the bulk of the liquid distills and gets condensed in the ampoule. The apparatus, now in su,ccessful use for over 3 years in this laboratory, enables micro distillation, under vacuum, of volatile liquids (.%SO mg) with negligible lnss. Transfer of the distillate is more complete and convenient (it may be sealed in the same ampoule also). The same unit can he reused several times by cleaning and re-fusing the same or a different ampoule a t B. The author wishes to thank Dr. Sukh Dev, Director, Malti-Chem Research Centre, for his interest and encouragement and Dr. N. P. Damodaran, Malti-Chem Research Centre for his helpful suggestions. 'Lieb. H., and ScMniger, W., "Arbeiten mit Kleinen Substanzmengen" in M e t h d e n Der Organischen Chemie (Houben-Weyl); Vierteauflage, (Editor:Miiller, E.),Georg Thieme Verlag. Stuttgart., 1959, Rand 112, p. 425. 2Cheronis, N. D., "Micro and Semimicro Methods", in Techniuqe of Organic Chemistry, (Editor:Weissberger, A,) Interscience, New York, 1957, Vol. 6, p. 75. 3Wright, G. F., J. CHEM EDUC., 26,422 (1949). 'Dev., Sukh, Unpublished work (Indian Institute of Science, Bangalore) (1959). Malti-Chem Research C e n t r e Nadesari 391340 Dist, Baroda India
124 / Journal of Chemical Education
Kishore M. Saplay
