I am an undergraduate research assistant in an Organic Chemistry laboratory. I'm working on this experiment that requires me to make LDA. I have the steps and procedure to make LDA, but somehow and somewhere I am messing up.
My LDA looks clear, sometimes slightly turbid, but never a clear yellowish color.
1. I flame dry and use a full vacuum for the round bottom flask
2. I let it cool
3. I add distilled diisoproylamine under inert N2 (.7 ml)
4. Add THF (6.6 mL)
5. let it cool to 0 C (using regular ice and water), wait 10 mins
6. add n-BuLi dropwise (.4 ml)
7. stir for 20 mins at 0 C
8. Cool to -78 C using dry ice and acetone
then from here, I follow the other steps my prof has asked me.
Please can someone give me some pointers or guidance. I"ve been working on this project the last 4 months and I can't seem to get it right. My LDA always looks clear like water, or slightly turbid. Please help. Thank you in advance.