Learning Outcomes and Procedure Learning Outcomes At the end of the session, student must be able to: 1. Write chemical reactions involved in some organic compounds such as alcohols, aldehydes and ketones, carboxylic acids and esters. 2. Differentiate tests for different organic compounds I. Materials Equipments /Apparatus Evaporating dish Pipet Test tubes beaker Stove Erlenmeyer flask Water bath set-up II. Chemicals 0.1% KMNO4 10% NaHCO3 6 N NaOH 6N H2SO4 C.P. HCl Acetone Acetyl chloride Benzyl alcohol Ethyl alcohol Formalin glycerol Methyl orange TS Methy alcohol n-butyl Alcohol Acetic Acid Acetophenone Anhydrous sodium carbonate Phenol Alcoholic Benzaldehyde Salicylic acid Whole Milk III. Procedure WARNING! Observe proper caution in handling and mixing organic compounds SAFETY Wear complete PPE. Label your test tubes properly to avoid mix-ups. Alcohols 1. Ester formation 1. Place in a separate test tubes 0.5 ml of the following alcohols: ethyl alcohol, n-butyl alcohol, glycerol, benzyl alcohol and phenol 2. Add to each (Caution! Perform near the sink or under the hood) 5 drops of acetyl chloride. Note any evidence of reaction 3. After a few minutes, add to each tube 1 ml of water and neutralize with about 5 drops of 10% NaHCO3 solution 4. Note the odor produced by each solution 1. Test for enol structure 1. Place 1 ml of the given solutions above in separate test tubes and dilute with 10 ml of distilled water 2. To each test tube add 5 drops of 10% ferric chloride solution 3. Note the color produced in each test tube. 2. Rate of oxidation 1. Place 2 ml of 0.1% potassium permanganate solution and 2 drops of 6 N NaOH solution in four separate test tubes. 2. Add 5 drops of each of the following samples: n-butyl alcohol, sec-butyl alcohol and tert-butyl alcohol into 3 separate test tubes. Leave the fourth test tube as a control. 3. Shake the tubes for a few seconds and observe any color change. 4. Repeat the procedure using 2 ml potassium permanganate and 2 drops of 6N H 2SO 5. Note the time of decolorization of the solution. Aldehydes and Ketones 1. Oxidation 1. Place separately in clean test tubes two drops of acetone and acetaldehyde solution 2. To both test tubes add 2 ml of Tollen’s reagent 3. Repeat the procedure, this time adding Benedict’s Reagent 4. Observe the change in color 2. Formaldehyde Milk Test 1. Add 2 drops of formalin and 2 drops of 10% ferric chloride to two ml of diluted (1:10) whole milk placed in a test tube,. Mix thoroughly. 2. Hold the test tube in an inclined position and pour carefully 1 ml of H2SO4 down the sides of the tube 3. Observe the interface between the two layers. 4. Compare with milk without any formalin. 3. Resin Formation 1. Place 3 ml of 6 N NaOH in a test tube. In another, mix 0.5 ml of 6 N NaOH and 2.5 ml of water. 2. Add 10-15 drops of acetaldehyde solution to both test tubes. Warm the mixture. 3. Observe all changes in color. Carboxylic Acid 1. Ester formation 1. Place 10 drops CH3CH2OH in a test tube and add 4 drops of dilute acetic acid and 1 drop of concentrated sulfuric acid 2. Warm the solution. Note the odor. 3. Repeat the procedure using methyl alcohol, salicylic acid (0.1g) and concentrated sulfuric acid 4. Note the odor of the resulting solution after pouring into a beaker containing one ml of water. 2. Effect of Oxidizing Agents 1. Place 5 drops respectively of formic, acetic, propionic, lactic, tartaric, citric, benzoic and oxalic acids in separate test tubes. 2. Place 5 drops of water into the 9th test tube to serve as a control 3. Render each alkaline solution with dilute sodium hydroxide 4. Add 5 ml of 0.1% KMnO4 solution to each of the test tube. Note any change of the color. 5. Heat gently to boiling. Observe any color change Esters 1. Hydrolysis 1. Place in a test tube 0.5g of acetyl salicylic acid. 2. Add 10ml of water and a drop of HCI. Boil gently for 3 – 5 minutes. 3. Filter off any undissolved crystals. 4. Add to the cold filtrate 1-2 drops of ferric chloride test solution. 5. Repeat the procedure using unhydrolyzed aspirin and compare the results 2. Ammonolysis 1. Add 3 ml of alcoholic ammonia to 1 ml of ethyl acetate. 2. Cork the tube and allow to stand until the next laboratory period. 3. Place the contents of the tube in a tared evaporating dish. Evaporate the alcohol over a water bath. 4. Observe what is left in the evaporating dish. Determine its weight. After the experiment: • • • Wipe your table with alcohol. Clean your area. Wash all the glasswares then dry inside the oven or wipe it with a tissue paper or a clean cloth. Return the glasswares and other materials to the laboratory technician and report any loss or breakages. In those cases, replace the missing glassware or the broken glassware on or before the deadline set by the Laboratory Division. WASTE DISPOSAL • • Neutralize acids and bases and pour down the sink with copious amount of water. Organic solvents should be placed in Organic Waste Containers in the fumehood.
