Shelly Amanda Zachary Harris CHE 231-401 Drawer #U26D Benzil Experimental Procedure 1. Place a magnetic spin vane and boiling chip in the 5.0-milliliter conical. Attach the water condenser to the conical vial. 2. Obtain 400-milligrams of benzoin product synthesized in the last experiment. Obtain 1.4 milliliters of cupric acetate solution, and mix the two together in a 5.0-milliliter conical vial. The cupric acetate solution will be prepared by the TA. 3. Attach the rubber tubing to the water condenser. SAFETY NOTE: Secure the attachment by wrapping copper wire around the tube. 4. Using this experimental setup:
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Heat the mixture between 140-145 degrees Celsius. Remember to stir the solution using a spin vane. Use a hot plate and an aluminum block to heat. SAFETY NOTE: Whenever heating in lab, remember to add a boiling chip. Heat the mixture for an hour. - There are many things to look for while heating this solution. The cupric acetate solution should dissolve the benzion within 5-10 minutes of heating. The solution should turn from a blue color to a green color. And nitrogen gas should be produced while heating. If none of these things happen within 15-20 minutes of heating, then more cupric acetate solution needs to be added. The TA will get this for you; it should be no more than 500 micro liters more of the cupric acetate solution. 5. After heating for an hour, cool the solution to room temperature. Add 2-milliliters of cold water to the solution 6. Use an ice bath to cool the solution for 10-15 minutes.
7. Use vacuum filtration to collect the crystals. Use the following set up:
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8. Rinse the product with 2-milliliter portions of water. Do this twice. 9. The product must be completely dry to get an accurate melting point and IR, press the product with two other filter papers to help the product dry. 10. Record the melting point of the product using the Mel Temp instrument. To do this, using a mortar and pestle, grind the product until it is Place powder. the powder on filter paper, and then add a small amount (2 mg) into the capillary test tube by scooping and then tapping the test tube to move the unknown sample to the bottom. Do this process twice for two capillary test tubes. Place a thermometer and the capillary test tube into the Mel Temp instrument. Observe the sample and record the temperature at which the sample changes phases from solid to liquid. 11.Record the IR spectra. To do this, use a Mini-Press (1 barrel and 2 bolts) and potassium bromide from the oven (KBr). Using a mortar and pestle, grind 100mg of KBr and 1mg of the unknown sample and then place it on filter paper. Then screw the bolt into the MiniPress. Loosen the screw by two turns. Scoop the power of KBr and the unknown sample into the Mini-Press. Remember to just barely cover the face of the bolt. After covering the face of the bolt with the powdered mixture, tighten the second bolt. To ensure the tightness of the press use two wrenches and hold the two wrenches tightly for five seconds. Then remove the bolts. Make sure that light is able to pass through the Mini-Press. Place the pellet onto the IR machine, and place the curved side onto the machine. Then set the IR machine to a frequency of 4000 and start the machine. MAKE SURE TO LOOK AT THE INSTRUCTIONS ON THE WALL. Compare the IR of the product to the standard. 12. If the melting point is not within 90-100 degrees Celsius, and the IR does not closely match the standard, then recrystallize the product using methanol or 95% ethanol.
13. Weight the product. You should have 250-milligrams. SAVE THE PRODUCT!!! Important Experiment Notes: - Wear gloves and an apron at all times during the experiment - Do all parts of the experiment in the lab. - Do not sniff/taste any of the chemicals in the lab. - MSDS information for the chemicals was looked for but not found. - Always add a boiling chip when heating a substance. - Use an aluminum block when heating a substance. - All waste goes in the soda lime container. Pasteur pipets in the broken glass disposal, and gloves in the nonhazardous solid waste container.