Apparatus adapter, for steam distillations

The apparatus illustrated is convenient for the steam-distillation of compounds which solidify in the condenser. By having the water condenser vertical, it can easily be cleared with a glass rod. No solidification occurs in the side arm, which behaves as a short air condenser. The adapter shown need not be specially constructed but may be assembled from commercially available components the dimensions and joint sizes are not critical. 

Manipulation. Since thionyl chloride attacks rubber, and since the usual reaction products are HCl and SO2, the reagent should be manipulated in all-glass apparatus with silicon grease on the glass joints, and provision should be made for entrainment of the gases. The best practice is to carry out the reaction in a round-bottomed flask fitted with a reflux condenser and drying tube and mounted in a hood the flask later can be fitted with an adapter for removal of excess thionyl chloride at the pressure of an aspirator on the steam bath and then for vacuum distillation of the product. Many workers employ thionyl chloride in large excess, but the evidence seems to show that no excess is needed in case the reaction is run at room temperature or if the mixture is refluxed under an efficient condenser cooled with water at 20° or below. 

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