[mir]

I see in the MSDS that MOMCl is a really nasty reagent. My tutor wants me to use MOMCl to protect  my phenol.

Do you have any tip how to handle this dangerous reagent, and precaution measures in case of emergency?

[movies]

MOM-Cl is no more dangerous than a lot of other chemicals that are commonly used in organic labs.  The main thing I would be concerned about are vapors (since it is a low MW compound) and skin contact (as always).  Wear good gloves and handle everything inside a fume hood with the sash down in front of your face.  You should be wearing goggles as well, but having the hood sash down will give you an extra layer of protection.  I do this whenever I deal with volatile lacrymators.  As long as you keep the bottle in the hood from the time you open to the time you close it again you shouldn't have any problems.  If you do spill some on your gloves, remove them quickly and leave them in the back of your hood.  Wash your hands and put on new gloves.

Remember that MOMCl is reactive toward nucleophiles like water.  When it sees water it's going to form HCl, formaldehyde, and methanol.  None of these is very fun to have on your skin, but think of how you would handle these reagents as a guide for how to handle MOMCl.  I'm sure you would be less apprehensive about using HCl in a reaction even though it's more reactive than MOMCl!

Don't be afraid of the reagents that you are using, that will just make you nervous and more likely to make a mistrake.  Respect the properties of the reagents and take the appropriate safety precautions and you should be fine.

[mir]

MOM-Cl is no more dangerous than a lot of other chemicals that are commonly used in organic labs. 
(...) I'm sure you would be less apprehensive about using HCl in a reaction even though it's more reactive than MOMCl!

It is the combination of high vapor pressure (higher than Ethyl acetate) and the cancer-risk - I dont like about this reagent. You may develop tumors at exposed areas of the skin or in the lungs.

I am going to make a solution of 40% KOH, so I can wash any equipment after use. I am also going to work with small amounts of the reagent.

Do you know if MOMCl will react violently with trace amounts of hydrogen peroxide?

Thanx for advices :-)

[movies]

It is the combination of high vapor pressure (higher than Ethyl acetate) and the cancer-risk - I dont like about this reagent. You may develop tumors at exposed areas of the skin or in the lungs.

I am going to make a solution of 40% KOH, so I can wash any equipment after use. I am also going to work with small amounts of the reagent.

Do you know if MOMCl will react violently with trace amounts of hydrogen peroxide?

Lots of things cause tumors, including more common things like benzene, pyridine, methyl iodide, and dichloromethane.  As long as you take reasonable precautions you should be fine.  If you are really worried about skin contact, wear a second set of gloves.

I would recommend using sat. aqueous NaHCO₃ to wash your equipment with.  It's not nearly as basic but it will certainly soak up any stray acid that might form.  Just watch out for foaming when it releases CO₂.

Definitely don't use any more of any reagent than you need to.  Working on big scale is orders of magnitude more dangerous than small scale, so it's always a good idea to start small and work your way up.

I can't thing of any specific reaction with hydrogen peroxide that would be much different than the reaction with water.  Chances are if you used peroxide in a previous step that you have as much water (probably more) than you do peroxide.

[Custos]

I encourage students to steer away from MOM-Cl for the reasons you mentioned. There are many other protecting groups for phenol alcohols that don't require as carcinogenic and volatile reagents. MEM, THP, benzyl, and one of the many silyl protecting groups would preferred choices - depending of course on how you want to take the protecting group off later.