Crystallization Lab Report

488 Words2 Pages
Experiment 3: Recrystallization Purposes: 1) To learn about the different types of extractions. 2) To learn to separate compounds based on their relative solubilities in two different immiscible liquids 3) To learn how to isolate the desired compound from a complex mixture. Procedure: Isolation of benzoic acid * In a Erlenmeyer flask, dissolve 50mg of unknown mixture of benzoic acid, p-nitroaniline and biphenyl in 10 ml of diethyl ether. * Add 5 ml of 6M NaOH and swirl to dissolve any residual solids. * Pour the solution into a dry, clean sep funnel. * Wash it with 1 ml deionized water. * Swirl the mixture, and allow the 2 layers to form and separate. * Add another 5 ml of 6M NaOH to the organic layer and repeat the extraction. * Place the Erlenmeyer flask containing the aqueous layer in ice bath and slowly add a minimum of 3.5 ml of 12M HCl. * Add more acid if precipitation does not occur. * Chill the mixture for 15 min. then vacuum filter. * Allow crystals to dry. * Weigh and calculate % recovery. Isolation of p-nitroaniline * Wash remaining organic layer with 5ml deionized water and extract aqueous layer into a beaker. * Add 10 ml of HCl to the remaining organic layer, shake , and separate the bottom aqueous layer. Repeat this step twice. * Collect aqueous layer into same Erlenmeyer flask and place into ice bath. * Precipitate the product using minimum 5ml of 12M NaOH. * Chill for 10 min. then vacuum filter. * Weigh and calculate % recovery. Isolation of biphenyl * Wash organic layer with 10 ml of deionized water and discard the aqueous layer. * Add 10 ml saturated Nacl solution. * Repeat extraction, saving organic layer. * Pour organic layer from the top into clean, dry Erlenmeyer flask and dry using Na2SO4. * Remove the drying agent by

More about Crystallization Lab Report

Open Document