I'm quite new to organic chemistry and want to try menshutkin reaction. Like the reaction in an attachment.

I use that recipe:

I do everything in a 60ml beaker. I dissolve 18 mmol of pyridine in 35 ml of acetone. I add 115 mmol of 1,6-dibromohexane and stir for 30 minutes. Then I add 76.6 mmol KOH (in the form of crushed pre-flakes). Stir for the next 24 hours.

Then I put the whole thing into a solution of 50 ml of dichloromethane and 100 ml of water. I mix for 1 hour, then pour into a funnel (I have a small 25ml one, so I do it several times).

I evaporate the whole thing using a 60-80 degree water bath until all the dichloromethane evaporates. Then, after cooling down, I wash it a few times with pentane (it cleans the material from the residual dibromohexane, unfortunately I don't have a vacuum pump).

Unfortunately, I only got 5% yield and the product still look little reddish, what am I doing wrong? Could you help me on what to do better?

I can buy equipment but not so sure what to buy

enter image description here

  • 1
    $\begingroup$ Dichloromethane? That's a bad idea en.wikipedia.org/wiki/Menshutkin_reaction $\endgroup$
    – Mithoron
    Jul 19, 2023 at 22:16
  • $\begingroup$ I mean when the reaction end of course, to transfer product to organic phase, It's not my imagination it's one of the procedure from Reaxys base. What do you think will be better that boils low temperature? $\endgroup$ Jul 19, 2023 at 22:27
  • $\begingroup$ Hmm, at this point it's probably indeed OK. Maybe adding pyridine drop-wise would help? $\endgroup$
    – Mithoron
    Jul 19, 2023 at 22:33
  • $\begingroup$ Last time I add 1,6-dibromohexane drop-wise, but can try with the amine drop-wise. The water-dichloromethane washing and pentane washing is ok? I thought maybe the reaction time is to long and another pirydine is brought to second bromine atom? $\endgroup$ Jul 19, 2023 at 22:49
  • $\begingroup$ Yeah, you need to do what you can to avoid disubstitution - adding pyridine slowly during reaction would be good idea. $\endgroup$
    – Mithoron
    Jul 19, 2023 at 23:06


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