Need help with creating an exact step by step procedure for a potential lab prac
ID: 1054712 • Letter: N
Question
Need help with creating an exact step by step procedure for a potential lab practical question. I get very confused when procedure steps are grouped together.
Materials available in Lab:
Solvents: acetone, ethanol, methanol, ethyl acetate, hexanes, DCM and Pet ether.
Aqueous Solutions: 1M NaOH, 1M HCl, 3M NaOH, 3M HCl, 1M NaHCO3, saturated NaCl
Drying agent: Sodium sulfate
special glassware: TLC chambers and plates, separatory funnels
Scenario: An organic chemistry student was attempting to synthesize aspirin (acetyl salicylic acid) from salicylic acid and the reaction did not go to completion and the student ended up with a mixture of both compounds. Purify the salicylic acid. Provide data to show that your compound is pure.
Thank You!
Explanation / Answer
After completion of the reaction. Extract the reaction with DCM. DCM layer is subjected to brine wash (Sat NaCl) and DCM layer concentrated.
Column chramatography is available load the compound on column. elute the column with ethyl acetae and hexane. First acetyl esalicylic acid will come. Then salicycliacid will come.
If column charamatography is not available go preparative TLC. Load the compound on glass silicagel TLC plate and run the TLC plate on TLC chamber with Ethyl acetate and hexane or MeOH and CHCl3. Based on UV activity mark the layer of acetyl salicylic acid and salicyclic acid. Scratch the marked TLC plateand filtered. You will get acetyl salicyclic acid. Finally check the melting points of acetyl salicylic acid (135) and salicylic acid (158-161)