In larger pilot plant or production equipment, the equipment can be dried and inerted by applying heat to the jacket of the reactor and vacuum to the equipment itself, isolation of the vacuum, and releasing the vacuum to the vessel with an inert gas. The vacuum/inert gas cycle should be repeated several times. The jacket may then be cooled to allow processing. An alternative is to apply heat to the jacket of the reactor and purge the vessel with an inert gas. It is also possible to dry a reactor train by boiling a water absorbing solvent, such as THF in the reactor under an inert gas. The solvent is then drained from the reactor, along with the water. The water content of the solvent can be determined analytically, for instance via Karl Fischer titration, to determine the efficiency of water removal. If the detected water value is higher than the background, the solvent boil up process can be repeated.
Sometimes it is more cost efficient to simply charge sufficient excess organolithium solution to account for the water content although all chemistry will not allow this shortcut.
Another hazard consideration for larger scale equipment is that the heat transfer fluid must be nonreactive with organolithium compounds. If there is a leak in the jacket or condenser and the heat transfer fluid comes in contact with the organolithium solution, the result can be catastrophic. Clearly this is not a risk worth taking on large scale although large-scale equipment rarely leaks into the vessel. Water, glycol, and brine solutions are examples of reactive heat transfer fluids that should not be employed as heat transfer fluids in this service.The suggestion about heat transfer fluid is something that is really important and (more or less) unique to the plant. To control temperature, reactor jackets are typically filled with either water, steam or ethylene/propylene glycol, all solutions that would happily react with nBuLi. There are silicon-based heat transfer fluids and I think that's what tends to get used in these situations, though I have no direct experience with that.
(Also, I'm amused at the suggestion of adding a little more nBuLi to get things dry -- world's most expensive drying agent? The thrifty process chemist would not agree.)
1. “Preparation, Properties, and Safe Handling of Commercial Organolithiums: Alkyllithiums, Lithium sec-Organoamides, and Lithium Alkoxides” Rathman, T. L.; Schwindeman, J. Org. Process Res. Dev. 2014, 18, 1192. dx.doi.org/10.1021/op500161b