Hallo guys,
I also prefer method in DCM.
I mixed 100g of Bromketon in 300ml DCM and slowly added 200ml of Methylamin 40%a.q. solution.
Now my question, what temperature and what time would be the best.
Last time I kept temperature at 36 - 37 degrees and reaction-time was 3hours.
But the product was extremly blue after acification.
How can I repair the relation between temperature and cooking time best.
Smaller temperature = longer reaction time?
Which temperature are not working.
Can anybody help and explain the reasons of temperature and cooking time?
Thank you a lot.
I also prefer method in DCM.
I mixed 100g of Bromketon in 300ml DCM and slowly added 200ml of Methylamin 40%a.q. solution.
Now my question, what temperature and what time would be the best.
Last time I kept temperature at 36 - 37 degrees and reaction-time was 3hours.
But the product was extremly blue after acification.
How can I repair the relation between temperature and cooking time best.
Smaller temperature = longer reaction time?
Which temperature are not working.
Can anybody help and explain the reasons of temperature and cooking time?
Thank you a lot.
- By TheVacuumGuy
My experience is that you can easily do it at 40 (rm temp! Use glass thermometer which goes into your mixture). DCM seems very reluctant to start actually boiling (like it has some buffer zone of sorts). If I increase temp it stubbornly keeps sitting at 40.
Either way. That relation time/temp thing is only important for those in a constant hurry. The fact that a reaction takes a certain time doesn't mean you need to stopwatch tightly. Product doesn't walk away. On 35 overnight, 25 overnight, 40 in 2 hours, 40 in 8 hours . you'll get the same output (where, imho, longer = better).
Either way. That relation time/temp thing is only important for those in a constant hurry. The fact that a reaction takes a certain time doesn't mean you need to stopwatch tightly. Product doesn't walk away. On 35 overnight, 25 overnight, 40 in 2 hours, 40 in 8 hours . you'll get the same output (where, imho, longer = better).
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- By TheVacuumGuy
Afaik methylamine is added in quadruple excess (foolproof). It depends on the conditions. High temps, rapid stirring, open vessel, ensures a lot of it evaporates (which is not what we want).
I roughly use x 1.5
It's actually a matter of just trying and find the optimal variables as you go . There are too much for a "one size fits all".
Last Saturday did 200g batch using 400ml ethyl acetate and 400ml methylamine. That failed heavily (twice).
as I'm typing, doing another 200g batch (image). 350ml methylamine, 500ml ethyl acetate. Never fails (for me, at least).
If I would use DCM i take 600ml DCM.
I roughly use x 1.5
It's actually a matter of just trying and find the optimal variables as you go . There are too much for a "one size fits all".
Last Saturday did 200g batch using 400ml ethyl acetate and 400ml methylamine. That failed heavily (twice).
as I'm typing, doing another 200g batch (image). 350ml methylamine, 500ml ethyl acetate. Never fails (for me, at least).
If I would use DCM i take 600ml DCM.
Attachments
- By TheVacuumGuy
400g bromoketone
1000ml DCM
800ml Methylamine
39 Celsius
6 hours (unintentionally, fell asleep)
In the morning added 1000ml water.
1000ml DCM
800ml Methylamine
39 Celsius
6 hours (unintentionally, fell asleep)
In the morning added 1000ml water.
- By TheVacuumGuy
It finished drying to complete dryness just now. i got 265,5 gram. Could have been higher if i actually didn't forget to wash it 3 times.
Will also get losses when crystallization to account for, so finally it will end up bit lower.
Will also get losses when crystallization to account for, so finally it will end up bit lower.
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- By TheVacuumGuy
i just finished reacting another one, 200g, 800ml DCM, 400ml Methylamine. ~2.5h 40 celcius.
now in freezer to prepare for acidify. curious to see if it yields more and better.
now in freezer to prepare for acidify. curious to see if it yields more and better.
- By TheVacuumGuy
yesterday acidified, white yellowish-hue (Cream-like), started with 500ml (freebase-in-solvent) when took it from the freezer.
Acidifying, became thick, pouring aceton made volume much larger , still thick., so sended up 2000ml still quite thick creamy like substance which looks beautiful.
I decide not for adding more acetone as, a moderate thickness keeps vacuumdistill much more clean.
This morning took it from freezer. Still the same beautiful off-white color. Took it through vacuum distill, no acetone needed ecept for rinsing the beaker of leftovers.
I used the same dish as the (400g couple of reactions above), to dry.
can't see by the eye exactly, but it looks like nearly (minus a bit) as much. will report when dry.
Acidifying, became thick, pouring aceton made volume much larger , still thick., so sended up 2000ml still quite thick creamy like substance which looks beautiful.
I decide not for adding more acetone as, a moderate thickness keeps vacuumdistill much more clean.
This morning took it from freezer. Still the same beautiful off-white color. Took it through vacuum distill, no acetone needed ecept for rinsing the beaker of leftovers.
I used the same dish as the (400g couple of reactions above), to dry.
can't see by the eye exactly, but it looks like nearly (minus a bit) as much. will report when dry.
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