Isolation of organic compounds from mixtures by solvent extraction.

EXPERIMENTAL PROCEDURE: 1. 2.07 g of the mixture of naphthalene and benzoic acid was weighed accurately on a balance. The mixture was then dissolved in 40 ml dichloromethane and the solution was poured into a separatory funnel. 2. 20 ml of aqueous sodium bicarbonate solution was added to the dichloromethane. A stopper was placed on the separatory funnel and was shaken and pressure was frequently released. The 2 liquids separated into clear layers and the lower layer (dichloromethane layer) was tapped …showed first 75 words of 281 total…

…showed last 75 words of 281 total…melting point. 6. The bicarbonate extract was acidified with concentrated HCl. A piece of litmus paper showed that it was acidic. 7. The benzoic acid was extracted by shaking it with25ml portions of dichloromethane. The organic extracts were collected in a pre-weighed Erlenmeyer flask and evaporated on the steam bath. The mass of Benzoic acid produced was determined. RESULTS (i) Naphthalene: 0.85g; Benzoic acid: 0.71g (ii) The melting point of Naphthalene: 80-89º c