NOVEMBER, 1947
GLASS CLEANING SOLVENTS E. MAXWELL DO88 Stanford University, California
ORGANIC CHEMISTS habitually use acid
cleaning solution whenever an obstinate deposit of tar or oil is encountered in their glassware. A little consideration as to the nature of the adhering material will often suggest a more effective and convenient solvent; e. g. basic tars would suggest the use of hydrochloric acid and, conversely, acidic tars,wouldsuggest usingsodium hydroxide solution. The old rule "like dissolves like" also has its applications in this instance; for example, hydrocar80n residues are often' removed by benzene, whereas partially oxidized tars are often loosened by acetone.
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A particularly useful solvent for removing greasy films from glassware is made with one volume of propylene glycol, one volume of chloroform, and powdered castile soap dissolved in the mixture.' This cleaning mixture functions better if slightly warm. Other halogenated solvents can be substituted for the chloroform but will not be as effective. Glassware washed in the above cleaning mixture should be rinsed with distilled water.
' Palit, S.,TEISJ o m n r . 23, 182 (1946).
