Communication pubs.acs.org/OPRD
Cite This: Org. Process Res. Dev. XXXX, XXX, XXX−XXX
Improved Safety during Transfer of Pyrophoric tert-Butyllithium from Flasks with Protective Seals Martin B. Johansen,† Jens C. Kondrup,‡ Mogens Hinge,*,† and Anders T. Lindhardt*,§ †
Department of Engineering, Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark § Department of Engineering, Carbon Dioxide Activation Centre (CADIAC), Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark Downloaded via UNIV OF SOUTH DAKOTA on June 17, 2018 at 07:01:53 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
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S Supporting Information *
“hands-free” setup was desired, that is, a setup in which the hands of the operator would be free to handle the syringe and needle during perforation and reagent extraction through the Sure/Seal. Because Sure/Seal caps are relatively difficult to puncture using small-gauge needles, this “hands-free” setup is intended to increase stability during perforation and extraction of air-sensitive reagents. In this communication, we report the development of a simple setup for the safe transfer of air-sensitive and pyrophoric reagents from Sure/Seal bottles. The setup relies on an airtight transfer vial in combination with a bottle cap aligner, and all parts are constructed from standard laboratory equipment and 3D printing.
ABSTRACT: A simple setup has been devised to facilitate safer transfer of air-sensitive and pyrophoric reagents from Sure/Seal bottles in a fume hood setting. The setup is composed of three parts; a sealed transfer vial, a custom bottle cap for transfer vial alignment, and a metal clip. All of the needed parts are constructed from standard laboratory equipment and by 3D printing. Titration of tert-butyllithium was used as an example of safe transfer of a highly pyrophoric reagent, and an instructional video has been prepared.
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INTRODUCTION Application of air- and moisture-sensitive reagents in a laboratory setting is generally a cumbersome task for chemists. Performing chemical reactions with such reagents requires perfectly dry conditions and operation under an inert atmosphere. Furthermore, if the required reagent is pyrophoric, then a careful safety consideration becomes imperative prior to reaction setup. tert-Butyllithium is the perfect example of an extremely air- and moisture-sensitive reagent and will spontaneously ignite if not handled correctly. The safety concerns that one needs to consider when handling solutions of tert-butyllithium cannot be underestimated, as is clearly exemplified by the tragic fatality of research assistant Sheharbano Sangji in 2009 at the University of California, Los Angeles.1 Sangji died as a result of burn wounds she received during a laboratory fire. This fire started during transfer of a tert-butyllithium solution, as the needle and syringe separated, thereby exposing the pyrophoric reagent to air. In a second-year laboratory course at Aarhus University, the living anionic polymerization of styrene is part of the curriculum. Polymerization initiates upon addition of tertbutyllithium dissolved in pentane to a solution of styrene at −78 °C.2 The tert-butyllithium solutions used in this course are from Sigma-Aldrich and come with the Sure/Seal system3 to protect the reagent from the surrounding atmosphere during transportation and storage. As the second-year students transfer the pentane solution of tert-butyllithium themselves, it was decided to review the safety setup around this addition step. Inspiration was obtained from a previously described method for the transfer of air-sensitive reagents that relies on a small double-septum canister used to isolate the needle tip.4 A © XXXX American Chemical Society
MATERIALS AND METHODS A Sigma-Aldrich Sure/Seal bottle of tert-butyllithium (25 mL, 1.7 M in pentane) is used as the example in this paper, but the developed method is amenable to most capsule-based sealing systems. The transfer vial was constructed from MachereyNagel crimp neck vials (10 mL, 22.5 mm × 46 mm) by fusing two top parts together.5 This design allows perforation of the crimp-cap seals several times if needed (Figure 1A). A 3Dprinted bottle-cap aligner and a simple metal clip were designed to keep the transfer vial locked in place during Sure/Seal perforation with the syringe needle (Figure 1A). Locking the transfer vial securely in the bottle cap aligner ensures the “hands-free” setup during syringe loading through the Sure/ Seal cap. Caution! All reaction f lasks, the transfer vial, and syringes must be caref ully vented with an inert gas prior to reagent transfer. All syringes should use the Luer lock system to prevent the needle f rom disconnecting during operation. Initially, the transfer vial is assembled by mounting a septum with crimp-cap lids onto each end followed by venting of the internal volume with argon or nitrogen to create an inert atmosphere. Next, the bottle is secured, holding the airsensitive reagents in the fume hood by clamps. The original Sure/Seal bottle lid is removed (but not the Sure/Seal cap), and the bottle cap aligner is mounted tightly. The reagent bottle is repositioned with the open section of the bottle cap aligner placed toward the operator. The transfer vial is inserted and locked using the metal clip, providing the setup shown in Received: May 8, 2018 Published: June 8, 2018 A
DOI: 10.1021/acs.oprd.8b00151 Org. Process Res. Dev. XXXX, XXX, XXX−XXX
Organic Process Research & Development
Communication
Figure 1. Safe transfer of pyrophoric tert-butyllithium from a Sure/Seal bottle. (A) Transfer vial locked inside the bottle cap aligner. (B) Correct positioning of the needle tip before transfer. (C) Syringe with transfer vial for inert reagent transfer. (D) Transfer vial centered on the reaction septum flask and delivery of the air-sensitive reagent.
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Figure 1A. The operator now has both hands free to carefully perforate the needle through both crimp-cap ends of the transfer vial and Sure/Seal. The correct volume of air-sensitive solution or reagent is then loaded into the syringe. Next, the needle is carefully extracted, with the needle tip placed inside the transfer vial (Figure 1B). Correct positioning of the needle tip inside the transfer vial is monitored visually through the open section of the bottle cap aligner. Removal of the metal clip allows the syringe and transfer vial to be lifted out of the bottle cap aligner (Figure 1C). Finally, the transfer vial is centered on top of the reaction flask septum sealing between the vial and the reaction flask septum (Figure 1D). Then the needle is inserted into the reaction flask for reagent delivery. An instructional video for the titration of tert-butyllithium with N-(o-tolyl)pivalamide is provided in the Supporting Information.6
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.oprd.8b00151. Instructional video (AVI) Full descriptions of the transfer vial and bottle cap aligner (PDF) Zip file containing the 3D printing file (ZIP)
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AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. *E-mail:
[email protected]. ORCID
Martin B. Johansen: 0000-0003-1638-6692 Anders T. Lindhardt: 0000-0001-8941-4899 Funding
The authors deeply appreciate generous financial support from the Independent Research FoundationTechnology and Production (Grant 4148-00031), the Danish National Research Foundation (Grant DNRF118), The Carlsberg Foundation (Grant CF17-0517), and Aarhus University.
CONCLUSION
A simple setup for improved safety during fume hood transfer of air-sensitive or pyrophoric reagents from Sure/Seal bottles is reported. All parts needed for the setup (the bottle cap aligner, transfer vial, and metal clip) are assembled from standard crimp-cap laboratory equipment and through 3D printing. The authors strongly believe that this simple setup significantly improves overall operator safety during transfer of pyrophoric reagents.
Notes
The authors declare the following competing financial interest(s): A.T.L. and M.H. are co-owners of SyTracks Aps and RadiSurf Aps, respectively, both of which commercialize the equipment. B
DOI: 10.1021/acs.oprd.8b00151 Org. Process Res. Dev. XXXX, XXX, XXX−XXX
Organic Process Research & Development
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Communication
ACKNOWLEDGMENTS The authors thank Dr. J. E. Friis, M.Sc. B. S. Kilsgaard, and M.Sc. M. L. Henriksen for their aid with 3D printing of bottle cap aligner prototypes and the Basic Polymer Chemistry class anno 2018 for testing and feedback.
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REFERENCES
(1) Kemsley, J. Researcher Dies After Lab Fire. C&EN Online Latest News, Jan 22, 2009. https://cen.acs.org/articles/87/web/2009/01/ Researcher-Dies-Lab-Fire.html. (2) (a) Szwarc, M. “Living” Polymers. Nature 1956, 178, 1168. (b) Grubbs, R. B.; Grubbs, R. H. 50th Anniversary Perspective: Living PolymerizationEmphasizing the Molecule in Macromolecules. Macromolecules 2017, 50, 6979. (3) For more information, see: Handling Air-Sensitive Reagents; Sigma-Aldrich Technical Bulletin AL-134; Sigma-Aldrich: St. Louis, MO. (4) Leonard, J.; Lygo, B.; Procter, G. Advanced Practical Organic Chemistry; CRC Press: Boca Raton, FL, 2012. (5) The transfer vial, bottle cap aligner, and metal clip are commercially available through SyTracks Aps and RadiSurf Aps. (6) Suffert, J. Simple direct titration of organolithium reagents using N-pivalol-o-toluidine and/or N-pivaloyl-o-benzylaniline. J. Org. Chem. 1989, 54, 509.
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DOI: 10.1021/acs.oprd.8b00151 Org. Process Res. Dev. XXXX, XXX, XXX−XXX
