All Questions
Tagged with experimental-chemistry purification
39
questions
0
votes
4
answers
333
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Storage of air and temperature sensitive reagents [closed]
What's your method for storing air/moisture and temperature sensitive reagents? For example:
A solid. Should I just blow some argon, screw the lid, put parafilm and put it in the fridge? Can a ...
user78790
-1
votes
1
answer
134
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Why is desalination waste usually disposed back into the sea instead of converting it into chemical products?
I was reading about the desalination processes such as reverse osmosis and capacitive deionization and their alternatives. They all work on removing ions from water and disposing them back to sea/...
- 223
2
votes
0
answers
172
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Evaporation of sample solvent and redissolving
When I conduct a synthesis, after some workups, I usually evaporate large amount of solvent using rotovap, recover compounds sticked to the wall of the flask to the glass vial using small amount of ...
- 1,101
1
vote
0
answers
252
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Reaction Workup and Quenching
In the supporting information of synthetic paper by Buchwald's group, They use 2-MeTHF as solvent (See B. General Procedures for Amination part, page 8). After the reaction ends and cools the mixture ...
- 1,101
1
vote
1
answer
90
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Water vapor permeation to the reaction flask
I am conducting a synthesis involving Buchwald-Hartwig coupling. The scale is $\approx10^{-4}$ mols of reagents. After running the reaction at 80 ℃ during 24 hours I found that sealing between the 3-...
- 1,101
2
votes
0
answers
314
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Analysis of reaction mixture by TLC and finding column chromatography condition
I am conducting an organic synthesis. Below is the TLC image.
I used dichloromethane:methanol:triethylamine=10:1:0.15 as eluent, but I stored it during 3 days, so it may be a little bit concentrated.
...
- 1,101
3
votes
0
answers
127
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Purification of Buchwald-Hartwig amination
I am conducting a synthesis involving Buchwald-Hartwig amination. I use $\ce{Pd2(dba)3}$, $\ce{P(o-tol)3}$, and $\ce{Et3N}$ as base. In many proposed mechanisms, they often omit the precatalyst. I ...
- 1,101
5
votes
2
answers
258
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Should I do solvent extraction for Buchwald–Hartwig amination?
I am conducting a synthesis involving Buchwald–Hartwig amination. Catalyst is $\ce{Pd2(dba)3},$ ligand is $\ce{P(o-tol)3},$ base is $\ce{Et3N},$ and solvent is toluene. Image below is the proposed ...
- 1,101
1
vote
0
answers
834
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Leakage during Celite filtration
I'm conducting a synthesis involving crown ether and Pd catalyst.
In many papers, prior to column chromatography, they filter crude mixture through a Celite pad.
I tried to, but leakage of Celite ...
- 1,101
3
votes
1
answer
334
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How can I filtrate Pd2(dba)3 and P(o-tol)3? (Celite filtration failed)
I am conducting an organic synthesis involving Stille coupling, using $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts. Reaction solvent is toluene in which the catalysts also dissolve. Many texts ...
- 1,101
3
votes
1
answer
169
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Is it possible to filter Stille catalysts using syringe filter?
I'm conducting an organic synthesis involving Stille coupling.
Stille coupling uses $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts.
Both catalysts dissolves in toluene which is the solvent of my ...
- 1,101
1
vote
1
answer
358
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Steam distillation vs fractional distillation
I am a high school student and I am a little confused in the techniques used to purify organic compounds. For example, in steam distillation we reduce the external pressure on the compound to be ...
- 252
1
vote
0
answers
61
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Extraction Techniques for Organic Compounds from Aqueous Media
I am looking to attempt an extraction of an organic compound that had just been prepared using a Friedel-Crafts acylation. The compound was prepared in MDC (~20 mL in total). After the reaction, the ...
- 2,010
1
vote
0
answers
36
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How to convert pepsin into powder form?
I have pepsin powder which is now hydrated due to humidity. I want to convert it back to the powder form. How to do it?
I don't have access to a freeze-dryer .
I prefer any cheap procedure other than ...
- 49
4
votes
1
answer
673
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How do I remove tetrabutylammonium perchlorate from an organic synthesis?
I am trying to remove tetrabutylammonium perchlorate (TBAP) from an organic synthesis where TBAP was used as an electrolyte. I am working with compounds containing the amide group. I have used flash ...
