Communication pubs.acs.org/OPRD
Vacuum Desiccator as a Simple, Robust, and Inexpensive NMR Tube Cleaner Thanh Binh Nguyen*
Org. Process Res. Dev. 2016.20:319-319. Downloaded from pubs.acs.org by UNIV OF SOUTH DAKOTA on 09/13/18. For personal use only.
Institut de Chimie des Substances Naturelles - CNRS-ICSN UPR 2301, Université Paris-Sud, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France Scheme 1. NMR Tube Cleaner
ABSTRACT: A simple, robust, and inexpensive apparatus for cleaning several NMR tubes is easily fit up and used from readily available glassware, including a beaker, a desiccator, and a rotary evaporator vacuum pump.
1. INTRODUCTION As part of our everyday work on the finding and optimization of new reactions, we were struck by the need for an effective method to clean rapidly several NMR tubes in a convenient manner with as little as solvent as possible from readily available labware. Commercially available glasswares for this purpose are expensive, fragile, solvent consuming, not easy to handle, and more importantly, not suitable for cleaning many tubes at once. Solutions for these drawbacks have been proposed,1 but none of them fulfills all the above-mentioned requirements. We present here a simple way to deal with this task. All we need is a vauum desiccator, a beaker that can fit inside the desiccator, and a rotary evaporator vacuum pump. 2. MATERIALS AND METHODS The operating instructions are presented in Scheme 1. First, NMR tubes to be washed are emptied and put upside down inside a beaker (step A). Cleaning solvent or solution (acetone, methanol, ethanol, water, nitric acid, aqueous NaOH solution, etc.) is next added to the beaker (about 4 mL for each tube). The beaker is put inside the vacuum desiccator (step B). A vacuum is subsequently applied to the system to remove air inside the tubes. The desiccator is next vented with air, and solvent will raise and clean inside the tubes. The vacuum/air vent cycle is repeated 3−4 times to remove all the air inside the tubes. The whole system can be left for one night for better results. Sonication of the beaker can also be performed if necessary as an aid to cleaning (step C). New solvent is changed, and the cleaning is finished with clean acetone (step D). This acetone can be used for the next time of cleaning. The number of NMR tubes that can be cleaned at once depends only on the size of the beaker and the desiccator. Caution: The desiccator should be opened in fume hoods. It is also recommended that the usual precautions (goggles, gloves, etc.) are taken. The NMR tubes can also be placed directly in the desiccator.
chemists, especially for those who work on high-throughput screening.
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*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) (a) Landrie, C. L.; Marszalek, R. J. Chem. Educ. 2011, 88, 1734. (b) Zhang, B.; Hodgson, J.; Hancock, W.; Powers, R. Anal. Biochem. 2011, 416, 234. (c) Mastbrook, D. W.; Hansen, E. A. Appl. Spectrosc. 1970, 24, 612.
3. CONCLUSION In this communication we present a simple and easy-to-use cleaning setup for several NMR tubes at once from a vacuum desiccator, a rotary evaporator vacuum pump, and/or a beaker. We strongly believe that this apparatus will be useful for organic © 2016 American Chemical Society
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Received: January 1, 2016 Published: January 6, 2016 319
DOI: 10.1021/acs.oprd.6b00001 Org. Process Res. Dev. 2016, 20, 319−319
