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Purification of laboratory chemicals Options
 
k.neo
#1 Posted : 3/18/2019 3:43:24 AM
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Was browsing the web for information on drying/purifying solvents and stumbled upon this.
Just google "purification of laboratory chemicals pyrobin", the pdf result is the one. The 6th edition, idk if there is a more recent edition.

Plenty of interesting information for an amateur like me.
Maybe you will find it useful.

For example:
Quote:
Acetone [67-64-1] M 58.1, b 56.2o, d 20/4 0.791, n 25/D 1.35880, pK 25/1 -6.1 (basic, monoprotonated), pK 25/2 20.0 (acidic) The commercial preparation of acetone by catalytic dehydrogenation of isopropyl alcohol gives relatively pure material. Analytical reagent quality generally contains less than 1% of organic impurities but may have up to about 1% of H2O. Dry acetone is appreciably hygroscopic. The main organic impurity in acetone is mesityl oxide, formed by aldol condensation. It can be dried with anhydrous CaSO4, K2CO3 or type 4A Linde molecular sieves, and then distilled. Silica gel and alumina, or mildly acidic or basic desiccants cause acetone to undergo the aldol condensation, so that its water content is increased by passage through these reagents. This also occurs to some extent when P2O5 or sodium amalgam is used.
Anhydrous MgSO4 is an inefficient drying agent, and CaCl2 forms an addition compound. Drierite (anhydrous CaSO4) offers minimum acid and base catalysis for aldol formation and is the recommended drying agent for this solvent [Coetzee & Siao Inorg Chem 14 2 1987, Riddick & Bunger Organic Solvents Wiley-Interscience, N.Y.,3rd edn, 1970]. Acetone can be shaken with Drierite (25g/L) for several hours before it is decanted and distilled from fresh Drierite (10g/L) through an efficient column, maintaining atmospheric contact through a Drierite drying tube. The equilibrium water content is about 10-2M. Anhydrous Mg(ClO4)2 should not be used as drying agent because of the risk of EXPLOSION with acetone vapour.
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