DMSO Basic information:
DMSO: dimethyl sulfoxide, is a colorless and odorless transparent liquid, with strong moisture absorption, high polarity, high boiling point, good thermal stability, and water miscible characteristics, it and most organic matter can be miscible, and has the title of “universal solvent”.
Melting point: 18.4 °C; Boiling point: 189°C
In organic synthesis, due to the good solubility of DMSO, we often use DMSO as a reaction solvent, but it is sometimes difficult to remove it due to its high boiling point during post-processing.
1, if the reactant is stable and resistant to high temperature, it is a good solution, with the oil pump, about 60 degrees, vacuum distillation can soon be removed;
2, if the reactants are not so stable, it is obviously not advisable to use oil pumps to pull. If the solubility of the reactants is not good, then slowly add a lot of water, the reactants may be out, filtration can remove DMSO; If not, add ethyl acetate, wash with 10 times the amount of water, can also remove DMSO in ethyl acetate (DCM is not recommended, because DCM solubility is too good, DMSO is not easy to completely wash off);
3, if the reactant is water-soluble, soluble in water, then can add volatile solvents such as chloroform, methanol, etc., in the water bath to evaporate dry, repeat several times, can also remove DMSO; If the laboratory conditions, you can use the freeze-drying machine to freeze, you can also completely remove DMSO, but it should be noted that the freeze-drying sample containing DMSO is easy to melt, you can add a little water when freezing;
4, if the above methods are not possible, you can pass through the positive phase column, but pay attention to one point, DMSO in the inside is equivalent to a large polar solvent, the column should be installed higher; You can also pass through the reversed phase column, first flush with water to remove DMSO, and then rinse with methanol, so that the sample is in the methanol phase, collect and concentrate the methanol to get the sample;
5, especially when our samples are relatively small, but also with deuterium DMSO sent nuclear magnetic, need to recover samples, freeze-drying machine is very useful; If the laboratory does not have this condition, then find a clean glass dish, pour deuterium DMSO into it, cover it with filter paper, and it will naturally evaporate clean in a few days.
