How can I prevent compounds with ester and carbamate group on a phenyl ring from hydrolysis even though I keep them in freezer with no solvent still I face excessive hydrolysis that is obvious in their LC/MS Charts.
Dear Nermin,
These kind of compounds should be stored in a dry place such as desiccator which contains drying agents such as molecular sieve, MgSO4 anhydrous or other drying agents. The air in the desiccator should be replaced with argon or nitrogen to make the environment inert.
The fact that you store these compounds in a freezer does the opposite effect since freezer is very humid and can supply water molecules to your compounds which results in their hydrolysis.
Hoping this will be helpful,
Rafik
Esters are relatively stable molecules. In general, a catalyst is required for their hydrolysis.
If you feel your sample is prone to hydrolysis, as mentioned by Karaman, it should be stored in a dry place. Normally, unstable compounds are stored below room temperature, to prevent / reduce heat-induced decomposition.
Thanks for you answers, yes I always thought it needs a catalyst to accelerate hydrolysis yet a sample showing 98% purity on LC/MS was shipped for biological assay , it was injected again before assay and showed some degree of hydrolysis , I was adviced to keep them in fridge to reduce heat induced degradation but now Karaman in advising to keep in dessicator, I will try to keep them under Argon or Ne in dry epindorff , hope it works.
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