Daniel's suggestion of the CO2 is good. I presume that the reason to quench to butyl lithium solution is that it is a residue in a large bottle. Thus small amounts. Many businesses now do a lab pack for disposal rather than quench. Quenching into alcohols, ethanol or IPA, is fine as long as it is under a positive pressure of N2 and transferred by syringe. The N2 should be attached through condenser to a flowing system which will serve to carry the butane away from the reaction location and can be directed into the hood vent. It is a good idea to dilute the alcohol with an inert solvent to slow the quench a bit. The use of syringe or dropping addition funnels is control of the rate, which is less likely in my opinion with pressurized transfers. As always with safety, it takes a bit longer to do it safely, but the rewards are great. A less well used version is to add to a solution of ethyl acetate, as in the case of CO2, to minimize outgassing. In either case, always add the reagent to be quenched to the excess quenching solution by a manner that allows control of addition and resulting heat generation. I had the unfortunate privilege of writing up a report and recommendations on how to do this years ago when an entire lab went up as a result bad technique and resulting panic in quenching nBuLi residues. Of course, also refer to the MSDS and to the Encyclopedia of Reagents for Organic Synthesis. As for the ether issue in the original email, distillation apparatus under a N2 atmosphere is best (see butane comment above). Many of us have concentrated ether under boil off conditions. I find it best to conduct the vapors away to the hood vent. Sounds like someone turned up the hot plate pretty hot, or the hood wasn't effective. Other solvents are also useful since the low boiling point of ether gives little latitude for using solubility improvements at higher temperatures. Lee -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU]On Behalf Of DanielD734**At_Symbol_Here**AOL.COM Sent: Friday, March 10, 2006 11:08 AM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: Re: [DCHAS-L] Questions out of my realm A safer butyl lithium quench: Slowly add the butyl lithium ( using a double tipped needle with nitrogen pressure) to crushed dry ice. The butyl group adds to CO2 and forms the lithium salt of pentanoic acid. The dry ice also keeps everything very cold. When adding butyl lithium to alcohol, butane is formed along with lots of heat. You are setting yourself up for a fire/explosion. ******************************************************** This communication and any files transmitted with it may contain information that is confidential, privileged and exempt from disclosure under applicable law. It is intended solely for the use of the individual or entity to which it is addressed. If you are not the intended recipient, you are hereby notified that any use, dissemination or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender. Thank you for your co-operation. ********************************************************
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