Hello everyone!
I have one question. I have couple of solvents and all of them were pure when they were bought but after some months or years of storage after opening I am not 100% sure about their dryness. What do you think is the easiest way to remove the residual water? Do you recommend molecular sieves? If so, could you recommend any product and the drying procedure?
The solvents are:
- DMF
- DMSO
- glycerol
- thiodiglycol
- 1-decanol
- diethylphtalate
- Methylene diiodide
- 1-bromonaphtalene
Thank you for the answers in advance!
Peter
Dear all, for traces of water molecular sieves are used. Also azeotropic distillation may be used for much higher amount of water. My Regards
Dear Peter,
Methods of purification of solvents and removal of water depends on solvents we are using. Again we should know about different methods available for chlorinated and non-chlorinated solvents. We have drying agents such as CaO, P2O5, CaH2, sodium, a mixture of benzophenone and sodium for thf. One has to be careful while choosing these drying agents. Please read the book Purification of Laboratory Chemicals by W L F Armarego & C L L Chai, Elsevier, or any other relevant book to get precise information.
Best
Balakrishna
Dear all, for traces of water molecular sieves are used. Also azeotropic distillation may be used for much higher amount of water. My Regards
Dear Peter,
You can use molecular sieves but it must be enough dried.
Regards
Sajid H
Hi;
The solvents can be dried by passing under nitrogen pressure over an activated alumina column (the amount of residual water is less than 10 ppm). This system does not require heating and is a perfectly safe alternative to conventional distillations. Please see the link below:
https://www.vac-atm.com/solvent-purification-system/
With my best regards
Dear Peter Machata I agree with Abdelkader BOUAZIZ and Md Sajid Hasan in that for all these solvents 4A molecular sieves should be suitable. Please also see this closely related RG thread entitled
"Which is the Best way to make Dry DMF?"
https://www.researchgate.net/post/Which_is_the_Best_way_to_make_Dry_DMF
Hello
You could try to use NaSO4 or MgSO4 to remove water from your solvents and then use molecular sieves to remove the traces of water.
About drying dimethylformamide (DMF); see: https://www.researchgate.net/post/Which_is_the_Best_way_to_make_Dry_DMF
About drying DMSO); see:
https://www.researchgate.net/post/dry_DMSO_preparation https://www.researchgate.net/post/What-is-exactly-means-for-dry-DMSO
About drying/purifying glycerol; see:
https://www.researchgate.net/post/What-is-the-easiest-quickest-and-cheapest-method-to-separate-water-from-dilute-glycerol-solution https://www.researchgate.net/post/Why_does_distilled_glycerin_take_on_a_pink_color
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