I learned the basic synthesis in DCM and I was curios how the cold one is done and it s nothing on the forum about that. It would be great if some expert could help with that
How 4mmc cold synthesis is done?
- Thread starter abis777
- Start date
The reaction time is very short, no more than two hours. The reaction itself is exothermic.
I think there is no point or possibility to even try to do this.
It is devoid of any logic
I think there is no point or possibility to even try to do this.
It is devoid of any logic
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- By PersonVPN
If you make 300-500 g, and do it in DMSO and similar solvents, then yes, of course! The reaction time is 15 minutes.
But if you increase the amount of reagents loaded at least tenfold, then I'm afraid you won't have enough 15 minutes to load all the reagents, to have time to cool the RM, and not to overheat the RM.
Now let's fantasize a little!
Imagine that you load 25 kg of BK4 into a certain vessel....
I'm afraid that at the very least you won't be able to fit it into your crystal washing device, and there can be no talk of stabilizing the reaction process!
So I can only wish you success in your kitchen, with your plastic products.
But if you increase the amount of reagents loaded at least tenfold, then I'm afraid you won't have enough 15 minutes to load all the reagents, to have time to cool the RM, and not to overheat the RM.
Now let's fantasize a little!
Imagine that you load 25 kg of BK4 into a certain vessel....
I'm afraid that at the very least you won't be able to fit it into your crystal washing device, and there can be no talk of stabilizing the reaction process!
So I can only wish you success in your kitchen, with your plastic products.
I hear it can be done but the reaction time goes through the roof.
Last night I started a batch of 50g BK4 with 70 ml MMA 40 % in 160 ml DCM. It started from cold (RM 8 °C) but the exothermic effect of the reaction brought the temp to 21 °C where it peaked and the rest of the reaction took place at about 15 °C. After 9 hours 20 minutes it looked quite nice (RM separated into layers nicely, the organic layer was reddish-brownish color), however during acidification the liquid turned black (dark blue, in fact. But so dark that it appeared black) and the precipitate was blue as well. It did respond to acetone washing but not enough to become white. Apparently I had some unreacted BK4 left in the RM and the reaction time should have been longer than 9 hours.
Last night I started a batch of 50g BK4 with 70 ml MMA 40 % in 160 ml DCM. It started from cold (RM 8 °C) but the exothermic effect of the reaction brought the temp to 21 °C where it peaked and the rest of the reaction took place at about 15 °C. After 9 hours 20 minutes it looked quite nice (RM separated into layers nicely, the organic layer was reddish-brownish color), however during acidification the liquid turned black (dark blue, in fact. But so dark that it appeared black) and the precipitate was blue as well. It did respond to acetone washing but not enough to become white. Apparently I had some unreacted BK4 left in the RM and the reaction time should have been longer than 9 hours.
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- By Naruto
Dcm need heat 2h with 40°c if u use dcm with NMP then is exotermic reaction and need 30min
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Everything is a combination of time and temperature. You can achieve a full reaction at 38 °C in two hours, or you can lower the temperature and increase the time. Apparently 9 hours was not sufficient time given the temperature of my environment. Next time I'll do it at 38 °C for a change.
Mate I'm literally just describing the fact that a chemical reaction finishes faster at higher temperature, and takes longer at lower temperature. This is a non-controversial basic principle taught at primary school. You're not doing yourself any favors by acting like it isn't true.
- By PersonVPN
1) The first possible reason why the RM is black is that you may have added the acid too quickly and overheated it. 2) The second MOST OBVIOUS reason is that you critically delayed the reaction time and got a whole bunch of by-products!
even using not the most suitable solvents for this synthesis, you still shouldn't carry out the reaction for more than two hours. But that's for (LARGE SCALE). And in your case, (50БК4) and an hour is too much!
even using not the most suitable solvents for this synthesis, you still shouldn't carry out the reaction for more than two hours. But that's for (LARGE SCALE). And in your case, (50БК4) and an hour is too much!
After flushing the free base I put it in the freezer so that everything was -18 °C entering the acidification: the free base, HCl, acetone were all freezer cold. I added HCl very slowly, one drop per second or slower. The liquid started turning black (extremely deep blue, in fact) after first few drops of HCl when the RM was probably still sub-zero. In no way can this be attributed to overheating and adding HCl too fast.
Two hours into the reaction the exothermic effect of the reaction already peaked and the temperature was coming down slowly, but there was no obvious color change yet. I've always struggled to get a full reaction so I opted to increase the time to allow all BK4 to react. Next time I'll apply heat and try to complete the reaction in a shorter time.
Two hours into the reaction the exothermic effect of the reaction already peaked and the temperature was coming down slowly, but there was no obvious color change yet. I've always struggled to get a full reaction so I opted to increase the time to allow all BK4 to react. Next time I'll apply heat and try to complete the reaction in a shorter time.
each solvent has its own specific temperature constant and its time. When you use one of the exothermic solvents, the time of the initial solvent is shortened with the time of the exothermic solvent because you use, for example, dcm and you think that without heating you will obtain an efficiency of 70% and a purity of 98%, then you can increase the efficiency, the efficiency will be max. 45 % and the purity of the product will not exceed 40% and the quality of the product will be like psychotropic pills sam speed 0 euphoria
reaction times don't go "through the roof".
if you have a decent overhead stirrer and a sufficient sized dimroth condenser, you can do perfect synthesis in DCM in 75 minutes .
It's recommended (by me) to heat the solution to 30c and then turn off the heater and start adding methylamine slowly (course of 45 minutes) with firm stirring.
(i've done it without heating too, with success, but heating before proceeds more efficient )
if you have a decent overhead stirrer and a sufficient sized dimroth condenser, you can do perfect synthesis in DCM in 75 minutes .
It's recommended (by me) to heat the solution to 30c and then turn off the heater and start adding methylamine slowly (course of 45 minutes) with firm stirring.
(i've done it without heating too, with success, but heating before proceeds more efficient )