Oxidative Decontamination of Chemical Warfare Agents in Swellable Hypercrosslinked Polymers Público

Abstract

The use of chemical warfare agents as a weapon of mass destruction has been well-documented for thousands of years, with chemical warfare in the modern era beginning during World War I. Sulfur mustard, commonly known as mustard gas, is of particular interest due to its high toxicity and potential for large-scale release. A catalytic system containing Brx/NOx species for the selective oxidation of mustard gas was developed in the Hill lab by Zhen Luo and was further advanced into the fastest known system for the selective sulfoxidation of a mustard gas analogue by Kevin Sullivan. Following the optimization of this catalytic system, a swellable hypercrosslinked polymer network, synthesized from the fluorobenzene monomer, was used to develop a solid-state system for the selective sulfoxidation of 2-chloroethyl ethyl sulfide, the mustard analogue. Delivery of this catalytic system into the pours of the polymer network was successful, and the swellability of the polymer was not significantly affected by the addition of the catalyst. It was shown that this polymer, following the integration of the catalytic system, is capable of selectively and completely oxidizing neat liquid 2-chloroethyl ethyl sulfide to the far less toxic oxidized product within 24 hours. This solid-state system is more potentially useful than previously reported oxidant systems, as they are often only functional in solution, which is impractical outside of a laboratory setting. Furthermore, this polymer’s swelling capabilities provides a unique opportunity to develop a material that both entraps an undesirable target such as a chemical warfare agent (CWA), like mustard, and decontaminates this entrapped agent. If such a multifunctional system could simultaneously signal the existence of the toxic compound, this multifunctional material would be even more interesting and potentially useful. This thesis addresses the possibility of such a multifunctional system.  

Table of Contents

1. INTRODUCTION                                                                                                       1

I. Chemical Warfare Agents                                                                                     1

           Figure 1. Potential products of sulfur mustard oxidation                      2

II. Brx / NOx Catalytic System for Aerobic Sulfoxidation                                   2

           Figure 2. Copper as a color indicator                                                          3

           Figure 3. Reaction rates using varying amounts of Cu(II)                      4

           Figure 4. Proposed reaction mechanism                                                    5

           Figure 5. Proposed reaction mechanism                                                    5

           Figure 6. A comparison of Zhen Luo and Kevin Sullivan’s Brx/NOx

catalytic conditions              6

           Figure 7. ¹³C NMR of products of sulfoxidation reactions.                     7

III. Swellable Polymer Networks                                                                             7

IV. Scope of Current Work                                                                                        8

2. METHODS AND MATERIALS                                                                                  9

I. Optimization of Brx / NOx Catalytic System                                                     9

II. Synthesis and Characterization of Polymer                                                   10

           Figure 8. Reaction mechanism for polymer synthesis                           10

           Figure 9. Desired polymer                                                                            10

III. Oxidation of CEES in Solution                                                                         11

           Table 1. Concentration of catalytic components                                     11

IV. Neat CEES Reaction in a Hypercrosslinked Polymer                                   11

V. Swellability of Hypercrosslinked Polymer-Catalyst                                      12

           Figure 10. Apparatus used to determine swellability                             13

3. RESULTS                                                                                                                     13

I. Optimization of Brx / NOx Catalytic System                                                    13

Figure 11. Optimization of [p-TsOH]                                                                        14

Figure 12. Optimization of [Br3^-]                                                                               15

Figure 13. Optimization of [NO3^-]                                                                             15

II. Synthesis and Characterization of Polymer                                                   16

           Figure 14. FT-IR spectrum of polymer                                                       16

           Table 2. Observed and literature FT-IR peaks                                          17

           Table 3. Elemental analysis of polymer                                                     17

III. Oxidation of CEES in Solution                                                                         17

           Figure 15. Oxidation of CEES in acetonitrile                                            18

IV. Neat CEES Reaction in a Hypercrosslinked Polymer                                    18

           Figure 16. Oxidation of 20 mmol neat CEES                                             19

           Figure 17. Oxidation of 10 mmol neat CEES                                              19

V. Swellability of Hypercrosslinked Polymer-Catalyst                                       20

           Figure 18. Qualitative swellability in dimethylformamide                    20

           Figure 19. Qualitative swellability in dipropyl sulfide                            21

           Figure 20. Qualitative swellability in neat CEES                                      21

           Table 4. Swellability, Q (mL g^-1)                                                                   21

4. DISCUSSION                                                                                                               22

 

5. CONCLUSIONS                                                                                                          25

 

6. REFERENCES                                                                                                             27

About this Honors Thesis

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School	Emory College
Department	Chemistry
Degree	B.S.
Submission	Honors Thesis
Language	English
Research Field	Chemistry, Inorganic Chemistry, Polymer Chemistry, General
Palavra-chave	polymer chemical warfare agent
Committee Chair / Thesis Advisor	Dr. Craig L. Hill, Emory University
Committee Members	Dr. Tracy Scott, Emory University Dr. Cora MacBeth, Emory University

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