Complete reduction of 2-chloroethylethylsulfide by hydrodesulfurization using mo-doped mesoporous substrates

Sorensen, Adam C.; Landry, Christopher C.

doi:10.1007/s10562-004-3441-x

Cited by 3 publications

(4 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As with most forms of amorphous silica, its internal and external surfaces are easily functionalized through reaction with organosilanes. We have recently shown that APMS is an effective substrate for chromatography and catalysis; − however, its large surface area and tunable spherical particle size also make it an attractive candidate as a vector for cellular transfection. Prior to these studies, data must be gathered regarding the conditions required for effective adsorption and desorption of DNA within the pores.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of DNA into Mesoporous Silica

Solberg

Landry²

2006

J. Phys. Chem. B

Self Cite

108

View full text Add to dashboard Cite

In these experiments, double-stranded, linear DNA sequences were adsorbed into the pores of spherically shaped acid-prepared mesoporous silica (APMS). The lengths of the sequences were either 760 base pairs or 2000 base pairs. DNA adsorption into the interior of the mesoporous material was confirmed using confocal microscopy of sequences containing fluorescently labeled DNA molecules. Additional characterization with N(2) physisorption and powder X-ray diffraction supported this finding. The extent of adsorption was measured at various concentrations using UV-visible spectrophotometry to establish adsorption isotherms. APMS alone adsorbed a negligible amount of DNA; however, exchanging divalent cations such as Mg(2+) and Ca(2+) into the pores of APMS prior to DNA uptake was found to cause a significant amount of DNA to be adsorbed. Using Na(+) caused a lower amount of DNA to be adsorbed. DNA adsorption was also dependent on the pore diameter of APMS. Adsorption increased upon expansion of the pore size of the metal ion-exchanged material from 34 to 54 A; however, no additional uptake was measured by further increasing the pore size to 100 A. The amount of DNA adsorbed could also be significantly increased by using (aminopropyl)triethoxysilane to covalently link ammonium ions to the surface. Postsynthetic modification of the silica surface with aminopropyl groups increased the maximum DNA adsorption to 15.7 microg/mg silica, for materials with pore diameters of 100 A, which is 2 to 3 times more adsorbed DNA than for metal ion-exchanged material. This indicated that DNA binds more strongly in the presence of the ammonium group compared to the metal counterions. Finally, calculation and comparison of Freundlich and Langmuir constants for these adsorption processes indicate that intermolecular interactions between the DNA molecules within the pores are significant when the effective pore diameter is small, including materials with larger pores that were modified with organosilane.

show abstract

Section: Introductionmentioning

confidence: 99%

Adsorption of DNA into Mesoporous Silica

Solberg

Landry²

2006

J. Phys. Chem. B

Self Cite

108

View full text Add to dashboard Cite

show abstract

“…As a consequence, the ability to efficiently decontaminate these highly toxic materials, with minimal environmental impact, has since become a global necessity. Of particular concern is the persistence of the potent vesicant bis(2-chloroethyl) sulfide (sulfur mustard, HD, Scheme ) which renders it a demanding decontamination problem. − There are several modes of decontamination available for HD including desulfurization, photocatalysis, dehydrohalogenation, aerobic (O 2 ) oxidations, and by hydrolysis to the low toxicity thiodiglycol (TDG) at metal oxide nanoparticle surfaces and zeolites . However, it is most practical to detoxify bulk HD oxidatively to the sulfoxide (HDO) with liquid decontaminants and herein lays a fundamental chemical challenge: most suitable oxidants are water-soluble, while HD is water immiscible.…”

Section: Introductionmentioning

confidence: 99%

“…Of particular concern is the persistence of the potent vesicant bis(2-chloroethyl) sulfide (sulfur mustard, HD, Scheme 1) which renders it a demanding decontamination problem. [3][4][5] There are several modes of decontamination available for HD including desulfurization, 6 photocatalysis, 7 dehydrohalogenation, 8 aerobic (O 2 ) oxidations, 9 and by hydrolysis to the low † Cardiff University. ‡ University of Bristol.…”

Section: Introductionmentioning

confidence: 99%

Locus-Specific Microemulsion Catalysts for Sulfur Mustard (HD) Chemical Warfare Agent Decontamination

et al. 2009

View full text Add to dashboard Cite

The rates of catalytic oxidative decontamination of the chemical warfare agent (CWA) sulfur mustard (HD, bis(2-chlororethyl) sulfide) and a range (chloroethyl) sulfide simulants of variable lipophilicity have been examined using a hydrogen peroxide-based microemulsion system. SANS (small-angle neutron scattering), SAXS (small-angle X-ray scattering), PGSE-NMR (pulsed-gradient spin-echo NMR), fluorescence quenching, and electrospray mass spectroscopy (ESI-MS) were implemented to examine the distribution of HD, its simulants, and their oxidation/hydrolysis products in a model oil-in-water microemulsion. These measurements not only present a means of interpreting decontamination rates but also a rationale for the design of oxidation catalysts for these toxic materials. Here we show that by localizing manganese-Schiff base catalysts at the oil droplet-water interface or within the droplet core, a range of (chloroethyl) sulfides, including HD, spanning some 7 orders of octanol-water partition coefficient (K(ow)), may be oxidized with equal efficacy using dilute (5 wt. % of aqueous phase) hydrogen peroxide as a noncorrosive, environmentally benign oxidant (e.g., t(1/2) (HD) approximately 18 s, (2-chloroethyl phenyl sulfide, C(6)H(5)SCH(2)CH(2)Cl) approximately 15 s, (thiodiglycol, S(CH(2)CH(2)OH)(2)) approximately 19 s {20 degrees C}). Our observations demonstrate that by programming catalyst lipophilicity to colocalize catalyst and substrate, the inherent compartmentalization of the microemulsion can be exploited to achieve enhanced rates of reaction or to exert control over product selectivity. A combination of SANS, ESI-MS and fluorescence quenching measurements indicate that the enhanced catalytic activity is due to the locus of the catalyst and not a result of partial hydrolysis of the substrate.

show abstract

“…Reduction of thioethers can also be used as a model for the conversion of mustard gas to less harmful compounds. Recently, our research group reported on the reduction of thiophene and CEES by hydrodesulfurization with H 2 , using Mo-doped mesoporous SiO 2 as the solid catalyst. , Mesoporous solids have particular promise as substrates in solid-phase catalysis because they have unusually large surface areas (routinely in excess of 1000 m 2 /g), large internal pore volumes, and narrow pore size distributions. Our studies have mainly focused on acid-prepared mesoporous silica (APMS), which has several additional advantages, since they have a spherical particle morphology with a controllable particle size between 1 and 10 μm, depending on synthesis conditions, and they may be synthesized in less than 2 h by a simple procedure.…”

Section: Introductionmentioning

confidence: 99%

Vanadium-Doped Acid-Prepared Mesoporous Silica: Synthesis, Characterization, and Catalytic Studies on the Oxidation of a Mustard Gas Analogue

et al. 2005

Self Cite

View full text Add to dashboard Cite

The room temperature, liquid-phase oxidation of 2-chloroethyl ethyl sulfide (CEES), an analogue of mustard gas, was investigated using vanadium-doped acid-prepared mesoporous silica ("V-APMS") as a solid catalyst. The V-APMS samples were prepared by wet impregnation with NH 4 VO 3 , followed by calcination. XRD, N 2 physisorption, SEM, and EPR were used to characterize the solid products. Samples with lower V contents (0.1-10 wt %) were found to contain isolated vanadyl species and were highly effective for oxidation of CEES to the corresponding sulfoxide and sulfone using tert-butyl hydroperoxide (TBHP) as the oxidant. Surface area and pore volume decreased significantly at higher loadings of V due to formation of V 2 O 5 within the pores of the solid. The mechanistic route involved V 5+ /V 4+ redox cycles during the catalysis process, as revealed by EPR studies.

show abstract

Complete reduction of 2-chloroethylethylsulfide by hydrodesulfurization using mo-doped mesoporous substrates

Cited by 3 publications

References 25 publications

Adsorption of DNA into Mesoporous Silica

Adsorption of DNA into Mesoporous Silica

Locus-Specific Microemulsion Catalysts for Sulfur Mustard (HD) Chemical Warfare Agent Decontamination

Vanadium-Doped Acid-Prepared Mesoporous Silica: Synthesis, Characterization, and Catalytic Studies on the Oxidation of a Mustard Gas Analogue

Contact Info

Product

Resources

About