Lead peroxide paste preparation

The product is then transferred to a large flask and distilled with steam to remove unchanged dimethyl-aniline the leuco-base is filtered when cool and recrystallised from alcohol. Almost a quantitative yield is obtained. The zinc chloride double salt of the dye is prepared as follows Ten. gms. of the base is dissolved in dilute hydrochloric acid containing 2 7 gms. of HC1 the liquid is diluted with 800 c.c. of water and 10 gms. of 40 per cent, acetic acid added it is then cooled with ice, and a thin paste of 7 5 gms. of lead peroxide added gradually with shaking. After standing a few minutes, the lead is precipitated by adding 20 per cent, sodium sulphate, and to tho filtrate from lead sulphate is added 8 gms. of zinc chloride dissolved iu a little water. The dye is then salted out by addition of common salt. Yield, abont 7 gms. 

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