A novel catalytic approach to the chemical detoxification of P-ester nerve agents

Abstract

An effective method for the destruction of P-based nerve agent simulants using the ester interchange reaction is described; depolymerization of polycarbonate in the presence of aryl phosphinates and KOBu^t (5 mol%) leads to a net breakdown of the toxic constituents of the simulants while immobilizing each component as a polymer end group; the data suggest that application of this approach to the destruction of nerve agents such as VX may be fruitful.

References

1. Y. C. Yang, Acc. Chem. Res., 1999, 32, 109; Y. C. Yang, J. A. Baker and J. R. Ward, Chem. Rev., 1992, 92, 1729.
2. M. G. Stanton and M. R. Gagné, J. Am. Chem. Soc., 1997, 119, 5075; G. Stanton and M. R. Gagné, J. Org. Chem., 1997, 62, 8240.
3. R. M. Kissling and M. R. Gagné, J. Org. Chem., 1999, 64, 1585.
4. M. R. Korn and M. R. Gagné, Macromolecules, 1998, 32, 4023.
5. In DMSO the pKa of butanethiol and naphthol are 17.0 that of phenol is 18.0 see: F. G. Bordwell, Acc. Chem. Res., 1988, 21, 456.
6. Mn = 852; DP = 3.4, PDI = 1.37. See : D. J. Brunelle, E. P. Boden and T. G. Shannon, J. Am. Chem. Soc., 1990, 112, 2399.
7. The linear PC was prepared by first dissolving it into THF, filtering it, precipitating it into an excess of MeOH, and finally drying in vacuo at 50 °C (M_n= 14 330; DP = 55; PDI = 1.99).
8. Chromatograms were obtained on a Hewlett-Packard 1100 LC instrument using a cyano-terminated silica gel column (LiChrosphere 100CN) for 1, and a silica gel column (DYNAMAX 60A) for 2. For 1, filtrate samples were run at 1 ml min^–1 in THF–hexanes (3∶7 v/v) with a gradient elution of 0.5% THF min^–1 for 10 min. For 2, filtrate samples were run at 1 ml min ^–1 in THF–hexanes (45∶55 v/v). A UV diode array detector was used for analysis.
9. As expected, no net reaction is observed with 2 and DPC..
10. Monitoring reactions in situ by ³¹P NMR while sequentially adding aliquots of catalysts indicated that after reaching ca. 5% conversion (10∶1 case), additional catalyst did not change the amount of unreacted phosphinate. Similar observations were noted for the 20∶1 experiments.
11. M. Kurata andY. Tsunashima, Viscosity–Molecular Weight Relationships and Unperturbed Dimensions of Linear Chain Molecules, in Polymer Handbook,3rd edn., ed. J. Brandrup and E. H. Immergut, Wiley-Interscience, New York, 1989, ch. VII, pp. 1–60.