Lab Instructor: Maciej Domaradzki
Labs 3 & 4
Objective: In steam distillation lab (lab 3), we must obtain pure Eugenol from cloves through the process of steam distillation. In the crystallization lab (lab 4) part 1, we must acquire the best possible pure crystallization of acetylsalicylic acid from aspirin and in part 2 we must obtain a similar pure crystallization of benzil from an impure mixture of benzil.
Materials: In lab 3, we used 75 g of cloves from which we must extract Eugenol. Water was largely used as a solvent. A polar solvent used was Dichloromethane. The drying agent used was Calcium Chloride. An acid and a base used were hydrochloric acid and Sodium Hydroxide, respectfully. The equipment used were a thermometer & holder, separatory funnel, classen adapter, 3-way adapter (distillation adapter), triple neck round bottom flask, west condenser, vacuum adapter, Erlenmeyer flask, 500ml & 50 ml beaker, Bunsen burner, rubber tubing, clamp holder & extensions, and graduated cylinder.
For both parts of lab 4, the heating source was the hot plate, the substances were heated in a 100ml Erlenmeyer flask, filtered using filter paper and a funnel with a neck, beakers, vacuum flask for additional filtration, and an electronic scale for weighing the crystals. The solvent used for both parts was 95% Ethanol that was also dripped on the crystals for purification. Ten tablets of aspirin were used in part one. Two grams of impure benzil were used in part two.
Lab 3 involved an intricate lab with many steps. We began by obtaining 75 grams of cloves and stuffing them into our triple neck round bottom flask. Then we poured 200 ml of water into the flask, put a stopper into 2 of the 3 necks except the middle one, and inserted a Classen adapter into that center neck. Into the Classen adapter went a separatory funnel in one neck and a 3-way adapter in the other neck. The Separatory funnel was filled with 50 ml of water. A thermometer and its holder were inserted atop the 3-way adapter for vapor temperature measurement. The side of the 3-way adapter was inserted into a west condenser, which itself was inserted into a vacuum adapter. The vacuum adapter was allowed to drip over an Erlenmeyer flask for collection of distillate. The entire setup was supported by clamp extensions & holders attached at the neck of the triple neck round bottom flask and the vacuum adapter for maximum stability and minimal leakage of vapors. The Triple neck flask was elevated over a Bunsen burner as a heat source. The water in the triple neck flask was brought to a boil, while doing our best to keep it from foaming. The aim here was to distill 60 ml of distillate. As soon as we collected close to 30 ml of distillate we added an additional 50 ml of water into the triple neck flask from the separatory funnel to keep the cloves submerged. Once the entire 60 ml of distillate was collected we needed to rid it of its water content. We transferred all of the distillate to our empty separatory funnel. We added 15 ml of Dichloromethane to the separatory funnel, inverted it (notice two layers forming), let the pressure out, and drained the organic material that was located at the bottom layer of the funnel into a separate collection beaker. This was done three times. For separate experimentation and reference of weight comparison a 5 ml sample of the not yet pure Eugenol drawn from the collection beaker. After drying with Calcium Chloride the Dichloromethane was boiled out on a hot plate, the remaining impure Eugenol was weighed, and stored away for later experimentation. The remainder of the impure Eugenol was treated with Sodium hydroxide to deprotonate the Eugenol. This was done three times in the separatory funnel adhering to the same principle of inversion and releasing the build up in pressure. However, from the two layers formed we expel the lower Dichloromethane layer and kept the top...
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