[freedi27]

1-(11-Mercaptoundecyl)imidazole

http://www.sigmaaldrich.com/catalog/product/aldrich/723088?lang=en&region=US

I have question on storing this chemical.
Last time, I kept it in the fridge but the seal was broken so it became soggy and I had to throw it away.
This time I kept it at room temperature in a dessicator and I feel like it's now in the usual powdery form.

Could anyone tell me how to store this type of chemical?

Also, when they say store chemicals in a dry, well-ventilated place, do they actually mean oxygen-free, water-free environment or dry in the general sense?

[wildfyr]

I would keep this in the fridge still. The storage conditions they give are ones to try to limit degradation of a 6 month-1 year time period (or more). And dry, well ventilated means the general sense. It would specify oxygen and water free.... though you usually cant go wrong storing something oxygen and water free. Maybe put it under an argon blanket, cap it quickly, and stick it in the fridge with a good seal to hedge your bets

[Babcock_Hall]

Why not keep it refrigerated in a small desiccator?  I have found that many jars work in this capacity, although a few seem not to (the desiccant goes bad after a few weeks or months).

[Nescafe]

1-(11-Mercaptoundecyl)imidazole

http://www.sigmaaldrich.com/catalog/product/aldrich/723088?lang=en&region=US

I have question on storing this chemical.
Last time, I kept it in the fridge but the seal was broken so it became soggy and I had to throw it away.
This time I kept it at room temperature in a dessicator and I feel like it's now in the usual powdery form.

Could anyone tell me how to store this type of chemical?

Also, when they say store chemicals in a dry, well-ventilated place, do they actually mean oxygen-free, water-free environment or dry in the general sense?

From experience I have noticed that sometimes the descriptions for storage are overstated (extreme) and sometimes very understated. For instance, we often use a peptide coupling reagent called dichlorotriphenyl phophorane in our laboratory. The storage conditions are as general as storing milk. Yet, the reagent goes bad if exposed at R.T. in a matter of a minute. So I found the best way to store it is buy a very small, plastic or glass desiccator such as this one http://static.coleparmer.com/large_images/06536.jpg that has an inlet, purge the flask with nitrogen or preferably argon and then store it in the fridge, it never goes bad. And if you even want to be extra careful you can weigh it under an atmosphere of argon but who has the time or the patience for that =)

Hope that helps,

Nescafe.

[ziqquratu]

I'll agree with Nescafe that the manufacturer recommendations are often over the top or way too lax! However, here's what I've found over the years:

1) Try to keep as many things - particularly things that are easily hydrolysed - out of the fridge as possible. So, for example, t-BuLi can't be reasonably stored at r.t., but n-BuLi may be OK if you use it up in a reasonably short period (say a month or two). Being in the fridge means that, no matter how well you store it, it's likely to pick up water during the heat-cool cycles when you use it, degrading it quicker.

2) Desicators may or may not work, but they do take up a lot of space - which is usually at a premium in lab fridges and freezers! Personally I never thought they were that useful.

3) A vacuum sealing device intended for storing frozen food is the most awesome tool I've ever come across for dry storage of reactive chemicals. I found this tip on a blog somewhere and I'm afraid I can no longer recall which one, but it saved us so much money in hydrolysed reagents. For example, we could keep a bottle of in the fridge n- or s-BuLi in a vac sealed bag for two months and it would titrate identical with when it was put in. Other reagents, such as triethylborane (used for making Et₂BOTf for aldol reactions), went from lasting weeks to being usable after 12 months. No dessicant or flushing the bag with inert gas - just stick the bottle in, suck the air out and seal. To be sure, I always used to parafilm the tops as normal, too, but I don't know how important that was.

Depending on the model, you can buy individual bags of various sizes, or you can get continuous rolls which you cut to length. I always cut a nice long length so it could be reused multiple times (you just cut off the seal, use the reagent then seal it back up - the bag gets a little shorter after each use, and may eventually need to be replaced but you get more value by using a long bag than making a new short one each time). I think they're some sort of laminated plastic, but they seem quite resistant to everything we stuck in them. As I recall, even a bottle of BBr₃ - which ate its own SureSeal - didn't break through when stored in the freezer

[kamiyu]

I am wondeing why the compound is water sensitive???

-SH group should be OK with water

[Babcock_Hall]

I don't know about water-sensitivity, but sulfhydryl groups can oxidize, and certain metal ions can catalyze this process.