[MasterChief]

I am recrystallizing a product of mine in hexanes. One of the starting materials contained BHT inhibitor. Will the BHT crash out along with the product or stay in the hexane solution?

On that topic, what are people's most successful ways of removing BHT from their products?

[opsomath]

BHT is usually present in small enough amounts that it doesn't affect a recrystallization, unless you have a special case of a very similar compound or a strong electron acceptor that forms a complex. I wouldn't worry about it unless you are seeing contamination.

[MasterChief]

My goal is for complete BHT removal as my product needs to be around 99.9% pure. I am hoping that it remains in the hexane solution.

[opsomath]

In that case, your best bet is probably to distill the starting material before the reaction, or remove it with activated alumina if it's a relatively nonpolar starting material. As I said, you can check with HPLC, but normally small impurities like that don't come through in a recrystallization.

[DrCMS]

Do you know how much BHT is in your starting material?  Typically it is only a few hundred ppm.
Do you know how soluble BHT is in hexane? I would guess it is soluble as the levels your likely to have.

So you can probably forget about BHT as an impurity; more likely to cause you an issue are any un-reacted reagents.

Before you try to "fix" this BHT issue that probably isn't one can you answer the following questions?
Do you know how stable your reagent is without the BHT?
Do you know if you can actually distil your reagent or if it will decompose/react first?

[MasterChief]

Chances are the BHT remained in the hexanes. I have limited access to instrumentation facilities unfortunately and was wondering if anyone else has encountered this particular situation.

If for some reason the BHT remains with the product, I will probably remove it pre-reaction in the future as the starting materials are not terribly unstable without it.

Anyways, I am open to a discussion on creative ways to remove BHT or other inhibitors as I am currently working on a project in which even the smallest of impurities need to be removed.