Present CWATIC interception, containment

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Zeolite Absorbents with Nucleophilic
Decontamination Properties
DTRA
D. C. Doetschman, C. W. Kanyi, S.-W. Yang, and
J. B. DeCoste Binghamton University, S. U. N.
Y., USA
Introduction

• Present CWA/TIC interception, containment
  decontamination issues.
• Need for methods that absorb and decontaminate.
• Need to absorb decontaminate simultaneously.
• Deployable as aerosol for threat interceptions.
• Potential for broad spectrum threat
  neutralization.
• Poster focuses on one chemistry of a broad
  spectrum solid state decontaminating absorber,
  responsive to these issues.

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Program Overview
Nucleophilic Chemsitry with NaX Faujasite Zeolite
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Overview of Zeolite Nucleophilic Chemistry
Zeolites have long been considered catalysts, but
there has been little emphasis on their role as
reagents until recently. Correa, Phys. Chem.
Chem. Phys. 2002, 4, 4268

• OzeoAH is chemically bound to the zeolite and
  releases no vapor.
• Na B-R- is an organic salt in the zeolite and
  releases no vapor.
• AR is a harmless olefin (ethylene derivative)
  gas that is usually released from the zeolite.
• Na B- is an organic salt in the zeolite and
  releases no vapor.

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The Faujasite Zeolite

• Zeolite are aluminosilicates composed of SiO44-
  and AlO44- tetrahedra.
• For each Al, a negative charge is created.
• The negative charge is compensated by cation.

• Cations occupy different sites.
• Cations are exchangeable.
• The zeolite has cages.
• 2 types of Faujasite, X and Y.
• Si/Al 1.2 (NaX), 2.4 (NaY).
• Salient chemical properties
• NaY unreactive, no supercage Na
• Basicity of supercage O atoms
• Cations attract anions formed

Sodalite cage (0.67 nm)
Supercage (1.3 nm)
Faujasite structure J. Phys. Chem. B. 109, 4738
(2005)
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Experimental Details
DTRA
Sample Preparation

• Zeolite dried at 450oC for 24 hours under vacuum
  (lt1.2 X 10-5 torr).
• Adsorbates (3 per supercage (s.c)) were
  freeze-pump thawed thrice before adsorption into
  the zeolite via evaporation.
• Products and residual reactant characterized
  using primarily liquid, solid NMR and IR
  techniques.

The adsorption apparatus used.
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Analytical Methods

• Load adsorbate/target in vapor phase or solution.
• Some experiments load stoichiometric H2O
  initially.
• Some experiments load stoichiometric H2O after
  reaction.
• Analyze residual products after adsorption
  reaction.
• Analyze contents in and vaporized from the
  zeolite.
• Analyze CDCl3 dimethylsulfoxide (DMSO) extract
  from slurry of the zeolite in the solvent
  followed by centrifugation.
• Analytical methods GC-MS, FTIR, liquid solid
  NMR (1H, 13C, 23Na, 27Al, 29Si, 31P), UV-Vis
  diffuse reflectance UV-Vis, TGA, DSC, XRD.

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CWAs/TICSs Related Adsorbates Examined

• Alkyl Halides
• Dihalides
• Phosphonates
• Carboxylic Acid Esters
• Sulfonates
• Thioesters
• Thiophosphonates
• Acyls
• Aryl Halides
• Alkenyl Halides

CH2XR, CH3CHXR, ... XF,Cl,Br,I etc.
RCOOR
RCOSR
e.g. RCOOCl
e.g. DDT, dioxins
e.g. Tri- Perchloroethylene (TCE, PCE)
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The Following CWA/TIC Chemistries Will Be the
Focus of This Poster
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Alkyl Halide Dihalide Chemistry
Unreactive Organohalogens
DTRA
Substitution and/or Elimination is Observed
For example
ethoxy
propene
13C spectra of NaX exposed to (a) ethyl bromide
and (b)1-bromopropane Ethoxy 69 ppm Propoxy 71
ppm Propene 114, 138 ppm
propoxy
a
b

• Substitution form framework alkoxy or
  carbocation
• Elimination commences with halopropane.

e.g. ethoxy
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Character of Zeolite Elimination Reaction
(i) Titration using NaOH Zeolite acidity
increased dramatically after adsorption of
2-chlorobutane.
(ii) IR assignments 1436 cm-1 Lewis (PyNa)
1548 cm-1 Bronsted(PyH) 1492 cm-1
superposition of 1436 cm-1 and 1548 cm-1

• Elimination
• No HCl gas produced pointing to acid zeolite
  (HX).

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Trends in Alkyl halide Chemistry

• Nature of Halogen Cl favors elimination ?I
  favors substitution.
• Length of alkyl chain short ? substitution long
  ? elimination
• Substitution 1o gt 2o, 3o(little or no
  reaction) steric effect on
• framework alkoxy stability, 1o gt 2o gt 3o.
• Elimination 1o favors substitution, 2o favors
  elimination, 3o no rxn.
• Internal elimination regioselectively favored
  more than in solution.
• Unlike solution carbocation chemistry, no
  migration of framework
• alkoxy is observed.
• Principles at work
• Competition between cleavage rates of C-X ?
  substitution vs.
• C-H ? elimination (note halogen dependence).
• Steric hindrance in backside attack for
  substitution less ? substitution
• more ? elimination extreme ? no reaction (note
  position order
• dependence).

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Alkyl Dihalide Chemistry

• Substitutional formation of framework haloalkoxy
  is
• generally possible, except in geminal
  dihalides.
• No alkyne formation through double elimination
• ?, ? dihalides both substitution and
  elimination.
• Elimination is favored in long-chain ?, ?
  dihalides.
• ?,? to ?,? dihalides
• Single substitution or single elimination may
  occur.
• Double elimination may occur to form diene, gt
  butyl.
• Elimination/substitution sequence may occur to
  form
• framework haloalkenyl species.
• As in monoalkyl halide chemistry, HCl is not
  released
• rather acid zeolite sites are formed.

Unreactive Organohalogens

• Chlorine on aromatic and multiple alkyl bonded C
  atoms undergo
• no substitution or elimination Cl elsewhere in
  an aromatic,
• alkene or alkyne is reactive. Transition states
  are unstable.

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Chemistry of the Phosphonate Nerve Agent
Simulants
DTRA
Dimethyl Methylphosphonate (DMMP) Dry Reactions
Dry conditions limit the degree of DMMP
adsorp- tion and reaction, especially without
solvent.
(I)
(DMMP)
(II)
Dry no added water
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DMMP Reactions in H2O Loaded NaX

• Water loading has several effects
• Hydrolysis products III, and IV form
• from I and II (or NaX catalysis).
• Dramatically better adsorption and
• reaction of DMMP is achieved at ca.
• 3 molecules of H2O per supercage.
• Loading in excess of 10 H2O per super-
• altogether inhibits uptake and reaction
• of DMMP.

Identification of I-IV were accomplished by
comparison with 31P chemical shifts of
the intermediates observed in solution hydrolysis
of DMMP and of the titration of an authentic
sample of IV.
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Diisopropyl Fluorophosphonate (DFP) Reaction in
Dry NaX
DFP
In the absence of water the DFP undergoes a kind
of elimination reaction with olefin formation and
acid zeolite site. Adsorption reaction is not
very complete.
IFP-
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DFP Reaction in Water Loaded NaX
DFP
Spectrum of the zeolite. (H2O loaded first)
(a)Spectrum of DMSO Extract. (H2O loaded last)
DFP. (b) Hydrolysis no NaX.
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Chemistry of the Isocyanates and the
Organo-sulfates -sulfites
DTRA
Typical Chemistry of Isocyanates
After NaX Reaction with Ethyl Isocyanate, 13C
CPMAS NMR
Ethyl Isocyanate in CDCl3 Solution 13C NMR
Product cannot be extracted with a wide range of
solvents.
Proposed reaction scheme
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Some Exceptions to the Typical Isocyanate
Chemistry

• Toluene-2,4-diisocyanate shows 13C evidence of
  typical product
• formation for the first isocyante group while
  13C and FTIR
• evidence exists for a remaining unreacted
  isocyanate group.
• The further reaction is only possible in the
  presence of H2O.
• Tertiary butyl isocyanate shows 13 evidence also
  of isobutene forma-
• tion, confirmed by GCMS headspace analysis.

Proposed elimination reaction schemegtisobutene
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Dimethyl Sulfate Chemistry

• Solid also shows weak 58.71ppm
• OMe 13C CPMAS NMR of re-
• sidual and/or methyl sulfate ion.
• DMSO extract has only residual
• dimethyl sulfate.
• In the presence of water, methanol and
• methyl sulfuric acid hydrolysis
• products are found in the extract
• (at 3.17 3.37 ppm in 1H NMR).

55.83 ppm
CPMAS NMR Of Zeolite After Reaction
Framework Methoxy
58.71 ppm
Artifact
Dimethyl Sulfate Solution NMR
13C
Proposed Reaction Schemes
H2O
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Dialkyl Sulfite Chemistry
Results are Analogous to Sulfate Chemistry

• Findings in dry zeolite (13C CPMAS NMR ppm
  indicated)

16.43
59.53
58.00
14.90

• Results with H2O present (1H DSMO
• extract NMR ppm indicated)

H2O
4.32
1.05
3.43
(?)
1.25, 4.01
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Summary Comments
DTRA
What Works in NaX Zeolite Nucleophilic Chemistry

• With DMMP, DFP, Alkyl Sulfites/ates, a second
  hydrolysis step may occur, giving more easily
  water-washed less harmful hydrolysis products.
• In the presence of moisture, initially present or
  added to the zeolite, a number of the species
  locked into the zeolite hydrolyze
• The OzeoAH species hydrolyze to harmless
  alcohols, generally easily water-washed from the
  zeolite.
• Except for NaCl, salt, formed from alkyl halides,
  the OzeoAH- anion hydrolyzes.
• Product is harmless or less harmful than the
  TIC/CWA.
• Product may or may not be easily washed out with
  water.
• The isocyanates appear to give products in which
  both covalent bonding to Ozeo and ionization to
  form an Na salt occur without breaking the
  molecule in two.
• Typical isocyanate products are neither
  hydrolyzable nor water-washable.

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What Doesnt Work

• Most Other Zeolites (unique NaX structural
  characteristics enable nucleophilic chemisty)
• Mustard Simulants (puzzling also an alkyl
  halide)
• Chlorinated Ethylenes (e.g. trichloroethylene
  tric/trike or TCE perchlorethylene PERC)
• Chlorinated Biphenyls (agent orange other
  herbacides)
• Molecules Too Large for Zeolite Pores (e.g.
  VX(?), biologicals, pesticides, etc. gt 0.7 nm
  pore window) even DMMP and DFP are slow to
  adsorb/react dry.
• Prolonged Operation in Wet/Moist/Humid Conditions
  (Too much water ties up the unique enabling NaX
  structural characteristics
• H2O coordinates the Na ion.
• H2O hydrogen bonds to the nucleophilic supercage
  O atoms.

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Should Try Next

• Acid Zeolite HX (e.g. sorb/kill bases like NH3)
• Basic Zeolite NaX (e.g. to sorb/kill acids like
  HCl (hydrogen chloride) gas and phosgene)
• Reducing Zeolite (e.g. Fe(II)X to sorb/kill Cl2
  chlorine gas)
• Bigger Pore Zeolite (e.g. the Swiss Cheese NaX
  zeolite developed in China, that were
  researching now, to sorb/kill larger VX,
  biologicals, pesticides, insecticides, etc.)
• Polymer-Zeolite Nanoparticle System (bigger pore
  system to sorb/kill larger VX, biologicals,
  pesticides)
• Alumino-Silicate Aerogel (bigger pore system to
  sorb/kill larger VX, biologicals, pesticides)
• Zeolite Bead Air Filters (individual, mobile
  facility, fixed installation protection)
• Aerosol Dispersal of Micron Powder Zeolite
  (proactive airborne threat interception
  neutralization)
• Broad Spectrum Defense
• Combine nucleophilic chemistry, redox, acid/base
  tailored beads or powders into broad spectrum
  cleanup sorbents, filters, or aerosols.
• Develop semi-permeable polymer skins to protect
  water sorption in wet/moist/humid conditions and
  to prevent cross-contamination by water added for
  hydrolysis.

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Publications of This Related Work
(DCD Ph. D. Mentor) J. D. Fox and A. Meenakshi,
Effects of tert-Butyl Halide Molecular Siting in
Crystalline NaX Faujasite on the Infrared
Vibrational Spectra, J. Phys. Chem. B, 109,
9917-9926 (2005).   (DCD Ph. D. Mentor) J. D.
Fox, Infrared Vibrational Spectra of tert-Butyl
Halides in Low-Aluminum HY Faujasite.
Vibrational Excitation Exchange and Other Effects
of Guest-Host Interactions, Chemical Physics,
325, 265-277 (2006).   Szu-Wei Yang, David C.
Doetschman, Jürgen T. Schulte, Justin B. Sambur,
Charles W. Kanyi, Jack D. Fox, Chrispin O.
Kowenje, Barry R. Jones, and Neesha D. Sherma,
Sodium X-Type Faujasite Zeolite Decomposition of
D imethyl Methylphosphonate (DMMP) to
Methylphosphonate. Nucleophilic Zeolite
Reactions I, Microporous Mesoporous
Materials, 92, 56-60 (2006).   Charles W. Kanyi,
David C. Doetschman, Jürgen T. Schulte, Kaking
Yan, Richard E. Wilson, Barry R. Jones, Chrispin
O. Kowenje, and Szu-Wei Yang, Linear, Primary
Monohaloalkane Chemistry in NaX and NaY Faujasite
Zeolites with and without Na0-Treatment.
Zeolites as Nucleophilic Reagents II,
Microporous Mesoporous Materials, 92, 292-299
(2006).   C. W. Kanyi, D. C. Doetschman, S.-W.
Yang, J. S., and B. R. Jones, Room Temperature
Reactions of Alkyl Halides in Zeolite NaX
Dehalogenation versus Dehydrohalogenation,
Microporous Mesoporous Materials, 108, 103-111
(2008).   Justin B. Sambur, David C.
Doetschman, Szu-Wei Yang, Jürgen T. Schulte,
Barry R. Jones, and Jared B. DeCoste, "Multiple
Effects of the Presence of Water on the
Nucleophilic Substitution Reactions of NaX
Faujasite Zeolite with Dimethyl
Methylphosphonate (DMMP)," Microporous and
Mesoporous Materials, 112, 116-124
(2008).   Charles W. Kanyi, David C. Doetschman,
and Jürgen Schulte, The Chemistry of Alkyl
Dihalides in Zeolite NaX at Room Temperature,
Microporous and Mesoporous Materials, doi10.1016/
j.micromeso.1008.06.005, (2008).   Charles W.
Kanyi, David C. Doetschman, Szu-Wei Yang, and
Jürgen T. Schulte, The Nucleophilic Chemical
Reactions of NaX Faujasite Zeolite with
Diisopropyl Fluorophosphonate (DFP), Microporous
and Mesoporous Materials, submitted for
publication (2008). 
Supported by US ARO/DTRA Grant W911NF-07-1-0042