Mike Marr 1/20/04 CH338 Tuesday, 8am CH338 – Lab #1: Electrophilic Aromatic Iodination Post-lab Report Results From 1.0072 grams of vanillin and 1.1766 grams of KI, my lab partner and myself obtained 1.8403 grams of 5-iodovanillin as our crude product. After recrystallization we obtained 0.6936 grams of 5-iodovanillin. Performing a Mel-Temp on our final product yielded a melting point range of 178 – 181 C. During our experiment we generated a total of 230 ml of liquid waste. Summary Crude product, 5-iodovanillin: 1.8403 grams, 6.612 mmol Final product: 0.6937 grams, 2.495 mmol MP range: 178 – 181 C Waste 10 ml EtOH 5 ml HCl 50 ml ethyl acetate 150 ml mother liquor Discussion In a 100 ml flask my lab partner and I added vanillin(1.0072g, 6.618mmol), potassium iodide(1.1766g, 7.088mmol) and ethanol(20ml). We cooled the mixture. Using a separatory funnel we added sodium hypochlorite(11ml) over a period of 10 minutes to our mixture. During this time we accidentally heated the mixture for approximately a minute. No harm was done. The reaction was a creamy coffee color. Adding sodium thiosulfate(10ml, 10%w/w) we then acidified the reaction mixture with hydrochloric acid(~5ml, 10% w/w). During the acidification, the mixture went from the creamy coffee color to a creamy coffee tinged with green. By the end of the acidification the mixture reverted back to a creamy coffee color. We proceed to use a rotary evaporator for 10 minutes to remove ethanol from the mixture. Using vacuum filtration we removed the crystallized crude product of 5iodovanillin(1.8403g, 6.612mmol) from solution. We dried the crystals and then proceed to recrystallize in hot ethyl acetate. After recrystallization we obtained our final product of 5-iodovanillin(0.6937g, 2.495mmol). We performed a Mel-Temp on our final product and obtained a melting point range of 178 – 181 C. -1- Mike Marr 1/20/04 CH338 Tuesday, 8am Conclusion Based on the Mel-Temp results(178-181) compared to the actual melting range of 5iodovanillin(183-185) I suspect that our product was primarily 5-iodovanillin, but contained impurities. More than likely these impurities were other mono-iodo substituted products. Our % yield was 38%, but I believe that if we had used our mother liquor, which contained some precipitate, to create a second crop of 5-iodovanillin that we could have increased our yield by a fair amount. -2-