Question

if applicacable, please write clear stepwise mechanism for all synthetic transformations, showing important internediates where appropriate. only do this if applicable for this lab.

Experiment SD Column Chromatography Running the Reaction. Once sodium borohydride has been added to the reaction meture Isee next paragraph take samples at the times just indicated. Because this must be done in such a short time you must be well prepared before starting the reaction. One person should be the timekeeper, and the other person should take the samples and spot the protes Spot each sample once, using a different pipet for each sample Place a magnetic stirring bar Technique 7 Figure ZBA OF 78C) into a 26-ml Erlenmeyer task. Add 0.40 9 of fluorenone and 8 mL of methanol to the task. Place the flask on a magnetic stirrer. Sor the mixture until at the solid has dissolved. Now take the first sample the second sample and spot the plate. Using smooth weighing paper, weigh 0.00 of sodium borohydride and immediately add it to the reaction mixture. If you want too long to add it, the sodium borhydride will become sticky, as it absorbs moisture from the air egin timing the reaction as soon as the sodium borohydride is added. Use the microp pets to remove samples of the reaction mouture at the following times: 15, 30, 50, and 150 sec onds. Use a different micropipet each time and spota TLC plate with each sample. On each plate, also spot the two reference solutions of fluorenone and fluoreno in acetone. After developing the plates and allowing them to dry, visualize the spots with iodine, as described in Experiment SA. Make a sketch of your plates and record the results in your notebook. Do these results indicate that the reaction went to completion? In addition to the TLC results, what other visible evidence indicated that the reaction went to completion? Explain Optional Exercise: Isolation of Fluorenol. Using a Pasteur pipet transfer the reaction me Ture to another 25- ml Erlenmeyer flask, leaving the magnetic stirring bar behind. Add 2 ml of water and heat the mature almost to boiling for about 2 minutes. Allow the task to cool slowly to room temperature in order to crystalline the product. Then place the task in an ice- water bath for several minutes to complete crystallization Collect the crystals by vacuum filtration, using a smal Buchner funnel (see Technique 8, Section 8.3). Wash the crystals with three 2-ml portions of an ice-cold mixture of 80% methanol and 20% water. After the crys- tals are dry, weigh them and determine their melting point literature, 153-154 C. 5D EXPERIMENT 5D Column Chromatography The principles of column chromatography are similar to those of thin-layer chro- matography. The primary difference is that the moving phase in column chroma- tography travels downward, whereas in TLC the solvent ascends the plate. Column chromatography is used more often than TLC to separate relatively large amounts of compounds. With column chromatography, it is possible to collect pure samples of the separated compounds and perform additional tests on them. In this experiment, fluorene and fluorenone will be separated by column chroma- tography using alumina as the adsorbent. Because fluorenone is more polar than flu- orene, fluorenone will be adsorbed to the alumina more strongly. Fluorene will elute off the column with a nonpolar solvent hexane, whereas fluorenone will not come off until a more polar solvent (30% acetone-70% hexane) is put on the column. The puri- ties of the two separated compounds will be tested by TIC and melting points. "Note to the instructor: The sodium bonohydride should be checked to see whether it is active: Place a small amount of powdered material in some methanol and heat it gently. If the hydride is active, the solution should bubble vigorously. If using an old bottle, it is also good to check the material for stickiness due to absorption of water. If it is too sticky, it can be difficult for students to weigh it out

Answer 1

This laboratory involves the chromatographic separation of a mixture of fluorene and fluorenone, which will be given to you previously prepared. This means there are no reactions involved in the preparation of the mixture you will separate. In addition to this, chromatography is a technique that does not involve reactions or any chemical changes, so there are no synthetic transformation throughout the whole experimental procedures.