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I would like to know if anyone has had any specific safety-related problems with Grignard reagents. I have taught the year-long introductory Organic Chemistry sequence for about 15 years and have never had a student get any Grignard Reagent on their skin, but I've always questioned how safe it really is to have students work with these compounds (specifically PhMgBr). I have never allowed my students to work with n-butyllithium (we don't even have any in our stockroom), so it seems an odd contradiction that I have much less reluctance to have them work with Grignard reagents.

The dangers of organolithium reagents, particularly t-BuLi and -- to a lesser extent -- n-BuLi are well documented. It seems to me that the danger of these reagents largely arises from the flammability of the solvent (hexane) in which the compounds are dissolved as opposed to their extreme reactivity as bases. The organolithium reagent as it reacts with moisture provides the energy needed to ignite the solvent. Since Grignard reagents are themselves extremely basic and dissolved in highly-flammable ethers, it would seem that the dangers of physical contact with a Grignard reagent would be equal to if not greater than those of using an organolithium reagent. Just out of curiosity, has anyone actually had experience with any accidents and/or injuries involving Grignard reagents?

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  • $\begingroup$ There is this incident that involves t-BuLi. Yes I know it's not a Grignard but if you read the article, which goes in a lot of technical detail, you might agree that it could have very well happened with a Grignard reagent and the main issue was not the high flammability of t-BuLi but low safety standards in the lab. On the other hand I believe that no organic chemist should be awarded a degree if he never performed a Grignard reaction as an undergraduate in the lab. $\endgroup$ – K_P Jan 27 '16 at 22:49
  • $\begingroup$ K_P I'm aware of the t-BuLi incident you mentioned. This is actually one of the things which got me worried about using Grignard reagents. I agree that it seems an essential experiment, though. I've done it every year I taught the lab. $\endgroup$ – ChemProfMatt Jan 27 '16 at 22:56
  • $\begingroup$ I think that an undergraduate experiment of standard preparation of a Grignard reagent is perfectly safe and gives the student the experience of performing a "serious" experiment. On the other hand if the experiment involves handling of a stock solution of a Grignard reagent requiring inert atmosphere, syringes, cannulas, etc then it wouldn't be suitable for undergraduates. $\endgroup$ – K_P Jan 28 '16 at 0:17
  • $\begingroup$ You could ask about what are the dangers, but asking about personal experiences isn't good idea here imo as questions should be about specific stuff and number of accidents described could be big. $\endgroup$ – Mithoron Jan 28 '16 at 0:27
  • $\begingroup$ It would be nicer if you restrict the scope of your question to speak about only one/two Grignard reagent(s). $\endgroup$ – M.A.R. ಠ_ಠ Jan 28 '16 at 7:35
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I have to disagree your position entirely.

Every chemical has associated hazards, with even the most unassuming chemicals having the potential to cause severe harm if not fatality.

However, the actual risk to the chemist is often severely minimised by taking sensible precautions, understanding the hazards, and working under a controlled set of conditions.

The whole purpose of organic chemistry education, especially the purpose of organic chemistry labs is to teach students how they should safely handle chemicals, not to tell them that they're too risky.

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    $\begingroup$ While I appreciate your point (yet do not agree with it), it's not at all what I'm asking about. I want to know if anyone has specifically encountered any kind of injury resulting from Grignard reagents mainly as an issue of personal curiosity. However, to your point, are you saying you would allow students in a second-year course (1st year of o-chem, after a year of g-chem) to work with potassium cyanide or lithium aluminum hydride? I'm talking about a class of 24 students each working independently. Even with the most careful supervision that's not a risk I would be willing to take. $\endgroup$ – ChemProfMatt Jan 27 '16 at 21:18
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    $\begingroup$ Perhaps we can continue this conversation in chat, as I think its worth exploring, but the stack exchange model doesn't encourage opinion based questions and answer. $\endgroup$ – NotEvans. Jan 27 '16 at 21:20

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