Synthesis of tert -BuCl

1. Synthesis of tert-BuCl CHEM 315 Week of November 8th, 2010 Alexis Patanarut

2. Due dates Today • GC of Distillate lab report - at the beginning of class • Carbon copies from your lab notebook - at the end of class Two weeks (after Thanksgiving break) • Synthesis of t-BuCl lab report • Includes synthesis scheme of t-BuCl • See http://classweb.gmu.edu/chemlab/sws/flow2.gif for example)

3. Purpose • To synthesize t-BuCl and learn how to do liquid-liquid extraction using a separatory funnel

4. Procedure – initial reaction • Obtain t-Butyl alcohol (11 mL) from instructor. Weigh vial and its contents, then pour the alcohol into a 125 mLseparatory funnel. Weigh the empty vial and take the difference to find the weight of the alcohol • Make sure the stopcock is closed before pouring anything in! • If the alcohol has solidified, you can liquify it again by warming it between your hands • Add 25 mL concentrated HCl to the alcohol on the separatory funnel and gently swirl the mixture for ~1 minute, unstoppered

5. Procedure – initial reaction • Put the stopper on the funnel and press down firmly, then gently invert funnel without shaking and carefully open the stopcock to vent • Close the stopcock again and shake the funnel several times, then release pressure through the stopcock • Repeat this shake/vent step for 2 - 3 minutes, then allow the mixture to separate into two layers. • Separate the two layers. • Which layer is on top based on density?

6. Extraction procedure • Must be done quickly, since t-BuCl is unstable in water and sodium carbonate • Use 10 mL portions of extraction solvents • Organic layer will be extracted (swirl and shake) once with water, two (2) times with sodium carbonate and once again with water • Swirl the contents gently in unstoppered funnel. Then put on stopper and carefully invert it, opening to stopcock to vent • Gently shake the funnel with frequent venting for ~1 minute, then allow layers to separate • Drain the lower aqueous/bicarbonate layer into waste beaker and keep top organic layer in funnel

7. Drying procedure • Drain organic layer into a small (50 mL) clean, dry beaker and add anhydrous sodium sulfate to the crude product, swirling until clear • Add drying agent using tip-fulls of large microspatula (0.5 g to 1.0 g), one portion at a time • Swirl the mixture during drying period • Watch for clumping of drying agent; if drying agent clumps, add a bit more • You want to add drying agent until you see some of it not clumping, at which you stop adding the drying agent; avoid adding too much drying agent, as that could reduce product recovery • When the solution is clear (dry), carefully decant the produce into a distilling flask using a funnel to prevent contamination of the flask neck

8. Distillation procedure • Add 1-3 boiling chips into distilling flask and distill crude product using simple distillation set-up • Collect distilled product into receiving vessel over ice • Might want to preweigh receiving vessel for later mass calculation purposes • Product will distill 3-4 deg C before and after literature b.p. of t-BuCl

9. For next lab period • Weigh the product and determine product (%) yield • Find refractive index • Get IR spectrum

10. Final notes • Store your t-BuCl in a tightly capped vial since it can evaporate very easily • Dispose aqueous solutions in the sink with plenty of water • Pour distillation waste into waste jar in the hood • Take good notes in your lab notebook! • Last two labs are more or less cumulative in the techniques you’ve learned this semester, so be sure to take good and thorough notes in your notebook • I will be checking your carbon copies for this!