Low-Pressure Extraction
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Suxhler extraction methuds in common Inburatmy urr l w e ;wernl oi-advmrngrs For rramplr, : t is d r e n nrrrsiary to use h i y l ~ - I > ~ i l l n ~ suhmts - p ~ i r ~ t(c.g.,w t e r , tolurnc~and prolmgcd hmtinp may c.nurr partial, or complete, dreumpositivn of thedr-ired pn,doct that is hcmncxtracred. ('vnvrr~rlv,uhrnlr,r.I>c,~l~nr-pctinr wkents ge.e..ethcr, ~ h l c , n h n , ,are used, there is usually some evaporationof solvent, unless a very efficient, daubie&eved condenser is used. We have circumvented these oroblems bvdevelooine modifications to a Soxhlet extractor that works at low oressure. This simole ?AYA~&~~us is shown i n the fieure:~he sul;stake to he extracted is chnreed in the thimhle (a) and the solvent .. poured into the round-blttc,mrd fl,~sk ill,. 'l'hr flask is heated on a wnrer bath at rhr de-ired rmlpLwaturr ,w.. 21) :I11 Y' ether; 50 1% "V tduenr).'l'hr apparnrus is wacuated via a water pump through s t q m r k ( C I rgr as ru make thesolvent huil while cooling the water condenser. Stoprock (c) is then cloaed and the extraction begins at reduced pressure and can continue for several days. We advise wrapping Teflon around the narrow part of the two joints (d, el and grease around the wider parts to avoid dissolution in solvent. This simple closed system avoids solvent lass with low-boiling-point solvents. ~~
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Albert0 Flarninl and Nicola Poll Institute di Teoria Strunura Elenronica dei Composti di Coordinaione del C.N.R.. Area della Ricerca di Roma, P.B. 10. 00016 Monterotondo Stazione. (Rorna), Italy
Volume 62
Number 6
June 1985
533
