I would like to make a formal report for my organic chemistry experiment.

1 Experiment 1 : Borneol; An Oxidation -Reduction Scheme 1. Introduction a) Oxidation of Borneol : Secondary alcohols, such as borneol , can normally be oxidized to ketones by any of a number of oxidizing agents. Hypochlorous acid, a thermally unstable weak acid, is one such agent. HOCl (pKa = 7.4) can be generated in situ by the acidification of a solution of sodium hypochlorite with acetic acid (a stronger acid, pKa = 4.76): NaOCl + CH 3COOH HOCl + CH 3COONa The oxidation mechanism is not fully understood, however, there is evidence that an alkyl hypochlorite intermediate is produced, which then undergoes an E2 eliminatio n to give the product, camphor. Complete oxidation of the borneol can be gained by ensuring that an excess of sodium hypochlorite is present. Starch -iodide paper is a good indicator of this. Under acidic conditions, hypochlorous acid oxidizes iodide ions to iodine, HOCl + H + + 2I - ----- > I 2 + Cl - + H 2O which then complexes with the starch to form a characteristic blue -black color on the paper. b) Reduction of Camphor : Metal hydrides of Group III elements such as sodium borohydride (NaBH 4) and lithium aluminum hydride (LiAlH 4) are sources of hydride ions (H -) and are commonly used in the reduction of carbonyl compounds. Lithium aluminum hydride is a very powerful reducing agent and reacts 2 viol ently with many common solvents as well as even moisture in the air. Borohydride is less versatile but is much easier to work with. We will use sodium borohydride to reduce camphor. The mechanism in which borohydride acts upon a ketone is: Note that all four hydrogens on a borohydride ion are available as hydrides. Thus one mole of borohydride can reduce four moles of ketone. However, an excess of borohydride is used since the purity of the material is often questionable. The final tetraa lkoxyboron compound (as well as excess borohydride) is decomposed at elevated temperatures: (R 2CH -O) 4B-Na + + 4R =OH ------- > 4R 2CHOH + (R =O) 4B-Na + 2. Experimental Read the chapter on reflux with addition in Zubrick. Re -read the chapters on extraction and washing . Oxidation: In a 25 mL RB flask set up for reflux with addition, 0.9 g of borneol, 2.5 mL of acetone and 0.75 mL of glacial acetic acid are stirred at 40 -50 0C. 1.2 molar equivalents of sodium hypochlorite are added in the form of bleach (5.25% aqueous sodium hypochlorite) by a dropping funnel over 3 approximately 10 -15 minutes. Once the addition is complete, stirring is stopped and a drop of the resulting solu tion tested with potassium iodide -starch paper. If necessary, an additional 2 mL bleach is added and the solution again tested. This is continued until an excess of bleach has been added, and then the reaction is continued for 5 more minutes. After th e solution is cooled to room temperature, the camphor is extracted ('microscale extraction') with dichloromethane (2 x 5 mL). Using the same pipette, the extract is washed successively with 5 mL saturated sodium bicarbonate (until the evolution of CO 2 ceas es), 5 mL saturated sodium bisulfite (check with starch -iodide paper), and water (2 x 5 mL). The dichloromethane extract is transferred to a dry flask or test tube and dried with granular anhydrous sodium sulfate for 10 to 15 minutes. The dried extract i s decanted (note: you must use all dry apparatus from this stage) into a pre -weighed glass sample container and the solvent evaporated in a sand -bath in the fume hood. The container is removed from the sand -bath immediately after the solvent has been remo ved since the product will quickly sublime. Leave the sample container open in your locker so that the sample dries completely. For the second week, read the sections on Infrared Spectroscopy in Zubrick. Week 2: The product is allowed to dry and the w eight recorded. The product is then identified by IR spectroscopy (as a nujol mull) and the following functional group tests. Obtain 13C NMR spectra of the starting material and the product from your instructor. Functional Group Tests: Functional group tests are quick reactions based on the chemistry of a functional group (or groups) that is (are) suspected to be present in a sample. The reaction will most commonly be accompanied by a color or phase change so that the presence or absence of the function al group can be determined. Whenever doing any functional group test, always do standards and blanks alongside the test compound(s) so that you interpret the result properly. 1) Chromic Acid Test: Test Procedure: Place 1 mL of acetone in a test tube, add 1 drop (or 20 mg) of test compound and mix. Now add 1 drop of the chromic acid/sulphuric acid solution (CrO 3 in H 2SO 4), and note the test result immediately. Run a test on acetone alone, as well as test compounds such as a tertiary alcohol, a seconda ry alcohol, a primary alcohol, an aldehyde, and your product. Allow all of these to stand for several minutes -- note any false -positive results which may occur with time. Discussion: This is a test for oxidizability and therefore at least one H must also be present on an alcoholic carbon. Thus primary and secondary alcohols give a positive result but tertiary do not. Most aldehydes can also be oxidized with chromic acid. It is a very rapid test, and shows a colour change, often with evolution of heat, instantly. Chromic acid reagent has been prepared for you ahead of time by dissolving 25 g of chromium 4 trioxide in 25 mL of sulfuric acid and slowly adding this to 75 mL of water. Week 3: Reduction: In a microscale round -bottom flask, the remaining camphor is dissolved in methanol (0.2 g camphor in 1 mL methanol) and 12 equivalents of sodium borohydride are added very slowly and intermittently with stirring, keeping the reaction solution at room temperature by cooli ng on ice. [Note: more methanol can be added during this procedure if necessary (ie. if it dries up)] When all the borohydride is added, a microscale reflux condensor is added and the solution is heated to boil for two minutes. The solution is cooled, ic e water is added (0.2 g camphor/ 7 mL water), and the solid collected by suction filtration via Hirsch funnel or filter tip pipette. Wash the product with cold water. The solid is dissolved in diethyl ether and then dried with anhydrous magnesium sulfate . The solution is decanted and the ether evaporated to give the product. Week 4: A similar qualitative analysis as that in week 2 should be carried out. Lab Report : From the 13C NMR and IR spectra, functional group tests, mechanisms of the reactio ns, and the molecular model kits provided, interpret the results of the experiment as thoroughly as possible. Is the final product after oxidation and subsequent reduction exactly the same as the starting material? Why or why not? Using mechanistic draw ings, fully explain your conclusions in your lab notebook . Pre -lab Questions 1. Complete an experimental scheme for the oxidation of borneol as well as the subsequent reduction. Be sure to include all calculated amounts (such as volume of bleach and w eight of borohydride) required and important times and temperatures. Note: An 'equivalent', 'molar equivalent', or 'stoichiometric equivalent' all refer to the stoichiometry of the reaction being considered. For example, in the reaction 1A + 2B ---- > C + D, if the recipe calls for 1.5 molar equivalents of B with respect to A and there is 0.5 moles of A, then one should add 0.5 x 2 x 1.5 = 1.5 moles of B. This is normally to provide an excess of one or more of the reactants either because of the cost of reactants and wanting to 'use up' all of the more costly ones or for ease of reaction work -up. 2. In the preparation of camphor, the extraction and washing routine can be confusing. Predict where the product will be as the procedure progresses. Why is the methylene chloride extract washed with sodium bicarbonate? ...sodium bisulfite?