Preparation of Cinnamic Acid from Benzylidene Acetone

Preparation of Cinnamic Acid from Benzylidene Acetone 

As soon as the calcium carbonate, which as been formed in th reaction, has settled to a thick mud, the supernantant liquid i.-transferred to an enameled vessel, passing it though a filter bag. Th clear solution is now very carefully acidified with 10% sulphuric acio solution (violent effervescence ensues on account of the presence of smaii excess of sodium carbonate). By this means the cinnamic acid is precipi tatcd as a snow-white mass, it is centrifuged off, and washed with coit water until the washings give no precipitate of barium sulphate wit) barium chloride solution. Source Lewinsohn 1924 

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