Porous porcelain, “ pot

For the determination of ICE using the oxygen flow rate method, a two compartment cell of 150 ml capacity was used the anode was a cylinder of 35 cm2 surface area and the cathode was a platinum spiral (4 cm2) enclosed in a 10 ml porous porcelain pot stirring was provided by a magnetic bar. 

The liquid should be poured into the distilling flask, preferably through a funnel the stem of which extends below the side arm, and a few fragments of unglazed porous porcelain ( porous pot, see Section 1,2)... 

A solution of 25 g. of sodium hydroxide in 500 c.c. of water is heated to boiling (porous pot ) in a distilling flask (capacity 1 1.) connected to a downward condenser which is provided with a receiver containing 60 c.c. of 2 A-hydrochloric acid. Through the corked neck of the flask 18-6 g. of nitrosodimethylaniline hydrochloride—preferably the moist reaction product—are added in portions. Each addition is only made after most of the oily drops of the base from the preceding portion have dissolved, and finally the liquid is boiled until it has become reddish-brown. The dimethylamine produced is trapped in the hydrochloric acid in the receiver at the conclusion of the distillation the contents of the receiver must still be acid. They are evaporated to dryness on the wateT bath in a small porcelain or glass basin, and finally the completely anhydrous salt can be recrystallised from a very small amount of absolute alcohol. Yield 5-6 g. 

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