Hi, will epsom salt that i just can buy from regular stores also do the work for me? Also how much is estimated used for this scale of synthesis. Few kg or are we talking couple 100 grams only.
Have you controlled temperature during reaction well?
Same question for you. Was temperature of reaction is higher than 55 deg C?
It is correct
does not exceed 55 or 60 degrees?
no2. unless you mean that the temperature should fluctuate between 55-60 degrees when adding methylamine?
When adding methylamine keep an eye on the temperature not to exceed 55 or 60 degrees? (Which option chemically speaking is more suitable giving a cleaner product / higher yield?)
Any examples of what to replace Benzene with? Toulene? DCM?
I get the purest product in DCM, but the main thing is not to let the solution boil, keep the temperature no higher than 36C (4-mmc turns out to be impeccably clean and snow-white). Another great option is dichloroethane. also a good result is obtained when using NMP and toluene together (3:2 ratio).
Reaction scheme:
Reagents:
- 2-Bromo-4'-methylpropiophenone (cas 1451-82-7) - 5 kg;
- n-Methyl-2-pyrrolidone (NMP; cas 872-50-4) - 20 L;
- Methyl amine 40% aq. solution (cas 74-89-5) - 8 L;
- Benzene - 20 L;
- Acetone - 30 L;
- Hydrochloric acid con. aq. solution (HCl 36%) ~ 1.5 L;
- Distilled water - 20 L;
- Magnesium sulphate (MgSO4);
Equipment and glassware:
- 100 L Batch reactor, which is equipped with drip funnel, top stirrer, thermometer, temperature control system (cooling) and reflux condenser;
- Funnel;
- pH indicator papers;
- Several buckets 25 L;
- Barrel 100 L;
- Beaker 2000 mL;
- Vacuum source;
- Scale;
- Measuring cylinder 1000 mL;
- Glass rod and spatula;
- Scoops;
- Nutsche filter;
- Rotary evaporator;
Synthesis procesuresMephedrone hydrobromide synthesis
Mephedrone hydrobromide synthesis from 2-bromo-4'-methylpropiophenone with n-methylpyrrolidone...
1. 2-Bromo-4'-methylpropiophenone 5 kg is poured into Batch reactor or another crude 2-Bromo-4'-methylpropiophenone amount after halogenation reactions.
2. n-Methyl-2-pyrrolidone 20 L is poured into the reactor. Top stirrer is turned on and the reaction mixture is heated up to 40 °С.
3. When temperature is reached 40 °С, methylamine 40% aq. solution 8 L is poured into the reaction mixture and stirred for 20 min.
4. Next, distilled cold water 20 L is poured into reaction mixture and stirred for few minutes.
5. Benzene 15-20 L or other suitable solvent is poured into the reactor, the mixture is stirred for few minutes.
6. Than, the stirrer is stopped, the mixture is divided into two layers.
7. The bottom aqueous layer is drained through the bottom valve of the reactor. Top layer is drained into a bucket and dried over MgSO4. Than, dry solution is poured in another bucket.
8. Ice acetone 20 L is added to the reaction mixture and hydrochloric acid (HCl 36%) is added dropwise with a constant stirring to reach pH 5.5-6.
9. The mixture is put into a freezer for 12 h.
10. Crystallized mephedrone hydrochloride is filtered on a Nutsche filter and air dried. The yield is 58%.
Note
NMP can be replaced by DMSO, DMF, Sulfolane.
I plan to set the temperature rigidly at 34 degrees (half of the given range of 32-36 degrees) and the reaction time at 4h.
can you have a closed bottle and stir later when the solution can no longer heat itself then set the water bath to 35 ° c and stir the bottle from time to time for 3 hours ??
can you have a closed bottle and stir later when the solution can no longer heat itself then set the water bath to 35 ° c and stir the bottle from time to time for 3 hours ??
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