Nucleophilic Degradation of Chemical Warfare Agents Using

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Nucleophilic Degradation of Chemical Warfare Agents Using Non-aqueous Decontamination Formula Jinxing Yang, Guomin Zuo, Lihong Qi, Liming Zhou, Rong Zhang, Shi Gao, and Yongjing Liu Ind. Eng. Chem. Res., Just Accepted Manuscript • DOI: 10.1021/acs.iecr.7b03640 • Publication Date (Web): 03 Dec 2017 Downloaded from http://pubs.acs.org on December 7, 2017

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Nucleophilic Degradation of Chemical Warfare Agents Using Non-aqueous Decontamination Formula

Jinxing Yang, Guomin Zuo*, Lihong Qi, Liming Zhou, Rong Zhang, Shi Gao, Yongjing Liu Institute of Chemical Defense, P.O. Box 1048, Beijing 102205, China

*Corresponding author: Guomin Zuo Address: The CWC implementation department, Institute of Chemical Defense P.O. Box 1048, Beijing 102205, China E-mail: [email protected] Tel: +86-10-52565376 Fax: +86-10-52565376

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Abstract: The degradation or removal of chemical, biological, and radioactive contaminants is a supporting technique for homeland defense and countering terrorism. A highly efficient, non-corrosive, non-aqueous formula based on alkali, alcohol, and amine was developed for degradation of chemical warfare agents (CWAs). The optimized formula consisted of 50% ethanolamine, 9% benzyl alcohol, 2% KOH, 28% dimethyl sulfoxide, and 11% 18-crown-6-ether, based on the decontamination efficiency against mustard (HD). The experimental results suggested that the volume ratio of the non-aqueous decontaminant formula to CWA should be no less than 30, 2, and 10 for HD, soman (GD), and VX to achieve >99% in 30 min. The non-aqueous decontaminant can be used to decontaminate CWAs over a wide range of ambient temperature, especially low temperature. It was shown that the main degradation pathway of HD was hydrochloric acid (HCl) elimination to give chloroethyl vinyl sulfide. GD and VX degradation pathway involved P–F and P–S bond cleavage, leading to nucleophilic displacement reactions. The non-aqueous formula presented excellent performance towards decontaminate CWAs contaminated concrete, alkyd paint coatings, and military exposure suits. Corrosion of the formula to metal materials and alkyd paint coatings was much lower than that by DS-2 decontamination solution.

Keywords: CWAs; a non-aqueous decontaminant; products analysis; degradation pathway

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1. Introduction In recent decades, chemical and biological counter-terrorism had come to the forefront of defense because of the immense threat to public and national security. A number of chemical and biological attacks on civilian populations have occurred, including the Tokyo subway sarin attack in 1995 [1] and the release of anthrax spores through the mail system in the USA in 2001 [2]. Advances in chemical engineering techniques have enabled terrorist groups to produce chemical warfare agents (CWAs) in makeshift laboratories, secretly and inexpensively [3]. Decontamination, i.e., making all contaminated objects harmless by removing and neutralizing pollutants, is one of the supporting techniques for chemical, biological, and nuclear defense [4]. Dozens of years, a series of decontaminants [5, 6] were developed for decontaminating different objectives, and most of them were based on the aqueous solution. However, the aqueous solution based decontaminant have many disadvantages in practical application, such as low decontamination performance, corrosive, electric, and frozen below 0 °C. Hereby, non-aqueous decontaminants attracted great attention [7-14] because they give excellent decontamination performances, make little damage to electronic equipment, and can be utilized in cold weather. In the last half-century, a range of non-aqueous decontaminants have been developed. In the 1960s, the US army was equipped with one of the earliest decontaminants, DS-2, which consists of 70% diethylenetriamine, 28% 2-methoxyethanol, and 2% NaOH [8]. In DS-2P [9], which replaced DS-2, the solvent was changed to propylene glycol monomethyl ether to reduce the need for logistic support. CD-1 [10, 11], which is used by the US air force, contains ethanolamine, propylene glycol,

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and LiOH; it reacts with GB and VX to produce hydrolysis products, and with HD to form a thiomorpholine derivative and chloroethyl vinyl sulfide. In the Netherlands and Belgium, they invented a formula named GDS2000 [12]; it consists of diethylenetriamine, aminobutanol, and NaOH, and deals well with contamination by CWAs in the temperature range −30 to +49 °C. The OWR Company developed GD-5 [12, 13] and GD-6 [14], which consist mainly of aminoethanol, benzyl alcohol, propanol, and KOH. GD-6 is more effective than GD-5 in handling HD contamination. In this work, the non-aqueous decontaminant formulas described above were optimized, and the effects of factors such as decontaminant: CWA volume ratio (V[formula]/V[CWA]), reaction time, and temperature were investigated. The degradation products were detected and identified using gas chromatography/mass spectrometry (GC/MS) to clarify the fate of the CWAs and the possible reaction pathways during decontamination. The efficiencies of the non-aqueous decontaminant in treating porous and non-porous materials (e.g., concrete, an alkyd paint coating, and a military exposure suit) contaminated with CWAs were evaluated under the optimum conditions. The levels of corrosion of metal materials and an alkyd paint coating in the non-aqueous decontaminant liquid were determined. 2. Materials and methods 2.1. Materials and equipment The toxic agents HD, GD, and VX (purity >95%) were obtained from the Institute of Chemical Defense (Beijing, China). Ethanolamine, benzyl alcohol, dimethyl sulfoxide (DMSO), KOH, 18-crown-6-ether, HCl, and ligarine (boiling range 90~120 °C, CAS:

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8030-30-6) were obtained from Bafang Agents Inc. (Beijing, China). An FYL-YS-50L constant-temperature reaction chamber was obtained from Fuyi Inc. (Beijing, China). A Vortex-genie 2 swirl oscillator was obtained from Scientific Industries Inc. (Bohemia, NY, USA). The pipette guns were obtained from Eppendorf Inc. (Hamburg, Germany). Because of their high toxicities, the CWAs were handled only by well-trained personnel, using appropriate safety procedures. 2.2. CWAs liquid–liquid decontamination reaction For liquid–liquid decontamination reaction [15], a certain volume of the non-aqueous decontaminant liquid was firstly placed in a 20 mL reaction bottle at a constant temperature. Then, CWA liquid was injected into the reaction bottle by a microsyringe and stirred for 2 min at 800 r/min. Samples (1 mL) were removed from the bottle at various time intervals (i.e., 5, 10, and 30 min), and 1 mL 10% HCl was added into the sample to end the decontamination reaction. Finally, the decontamination efficiency and degradation products were determined. 2.3. Analysis of CWAs and their degradation products 2.3.1. Sample preparation The unreacted CWAs and newly formed products were quickly separated from the decontamination solution using a liquid–liquid extraction method. Ligarine (1 mL) was used to extract the residual CWAs in the mixture. The organic and aqueous phases were well separated, and then GC/FID was used to determine the amount of residual CWA in the ligarine solution and GC/MS was used to identify the CWA degradation products. 2.3.2. Analysis of CWAs and their degradation products

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The CWA residues extracted from the ligarine solutions were analyzed quantitatively by a Bruker 450-GC instrument equipped with a flame ion detector (FID) an HP-5 capillary column (30 m × 0.32 mm i.d.; film thickness 0.25 µm) employing the temperature ramp 50-280ºC at 15ºC/min. The degradation products were identified by 7890A-5975C GC/MS (Agilent Technologies, Palo Alto, CA, US) equipped with HP-5MS capillary column employing the temperature ramp 40-280ºC at 10ºC/min. [16] 2.4. Surface Decontamination of CWAs on various materials Various common materials were chosen as contaminated object, e.g., military exposure suits (10cm×10cm), concrete (d=8cm), and alkyd paint coatings (10cm×10cm). The experimental procedure was as follows. [17] Firstly, the experimental agents and equipment (i.e., the CWA, the non-aqueous decontaminant liquid, the test material, and a micro-syringe) were preheated in a thermostatic chamber at a given temperature for 1 h. Then several drops (about 25 µL per droplet) of the CWA were uniformly dispersed on the material surface using a micro-syringe. The HD and VX densities on the contaminated surface were about 20 and 5 g/m2, respectively. The contaminated materials were then decontaminated by spray about 3 mL of the non-aqueous decontaminant for 1 min. The decontaminated samples were laid aside for 30 min, and then 5 mL 10% HCl solution was added to end the decontamination reaction. Three ligarine cotton-balls were applied to wipe the decontaminated surface to obtain samples for analysis. The cotton-ball samples and the treated contaminated materials were extracted

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separately with ligarine (10 mL) to determine the residual amounts of the CWAs. 2.5. Decontaminant causticity tests A China industry standard causticity test method [18] was used to determine the causticity of the non-aqueous decontaminant and DS-2. The tested materials included four metals (i.e., stainless steel, carbon steel, copper, and aluminum) and an alkyd paint coating. First, jars (1000 mL) filled with decontaminant liquid (600 mL) were placed in a thermostatic chamber. The prepared samples (three pieces) were weighed and immersed in the decontaminant liquid for 72 h (24 h for the alkyd paint coating). The immersed samples were then cleaned and weighed again. The degrees of corrosion of the tested materials were evaluated using the following equation: R = 8.76 × 107× (M – Mt)/(Std)

(1)

where R is the etching rate (mm/a), M is the weight before immersion (g), Mt is the weight after immersion (g), S is the surface area of the tested material (cm2), t is the immersion time (h), and d is the density of the tested material (kg/m3). 3. Results and discussion 3.1. Optimization of non-aqueous decontaminant formula 3.1.1. Choosing ingredients for non-aqueous decontaminant The developed non-aqueous decontaminant consisted of an alkali, alcohol, and amine, each ingredient play an important role in the effective degradation of CWAs. The amine acts as a clathrating agent, which sequesters the sodium cation of the alkali; this frees the hydroxide ion to form a superbase (i.e., pKa > 14). This superbase then interacts with the alcohol, forming the alkoxide ion (MCO−), which acts as a nucleophile in the non-aqueous system. The nucleophilicity of the RO- is the most important factor for decontamination reaction. In addition to serving as the nucleophile source, the alcohol also functions as a 7

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mutual solvent for the base, the amine, and the agent [19], but excess alcohol can hinder the decontamination reaction because of the solvation effect. To obtain an ideal formula, alcohol amines (i.e. ethanolamine and isopropanolamine) were selected as the main ingredient, because they contain both amine and alcohol functional groups, and can act as both chelator and solvent. Besides, this two chemical can be widely available and virtue of low toxicity. The choosing of alkali is associated with the selected amine, here we choose NaOH and KOH as alternative component. For alcohol, two alkanes alcohol and two aromatic alcohol was selected as the alternative ingredient. An orthogonal experiment was designed to select the preferred ingredients, where including three factors: factor A for alcohol, which includes four levels (NO.1 for isopropanol, NO.2 for benzyl alcohol, NO.3 for n-butyl alcohol, NO.4 for phenethyl alcohol); factor B for alkali, which includes two levels (NO.1 for NaOH, NO.2 for KOH); factor C for amines, there are two levels (NO.1 for ethanolamine, NO.2 for isopropanolamine). According to the given factors and levels, the experimental scheme is arranged with mixed-level orthogonal array L8(41×24). Eight examine experiments were carried out to evaluate the decontamination efficiency of HD (Table 1). The experiment results indicated that the decontamination performance of the formulas containing the two amines have no significant difference, but ethanolamine is more economical, less viscosity and better solvency for alkalis. The formulas containing KOH is obviously superior to those contain NaOH. This suggested that the chelation effect of amines on K+ is stronger than that on Na+. And that, the results indicated that the behavior of benzyl alcohol is better than other alcohols. Based on the experiment results, we selected ethanolamine, KOH and benzyl alcohol as the main ingredient of the decontamination formula.

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Nevertheless, the alcohols as protonic solvent may decrease the nucleophilicity of RO- in the decontamination solution. Hence, the addition of non-protonic solvent and chelating agent is very necessary. Based on the comprehensive consideration of availability, virtues and interaction mechanism, DMSO and 18-Crown-6-ether were selected as the ingredients of the formula. DMSO is an important polar and aprotic solvent that dissolves most chemicals, it interacts more strongly with positive centers than alcohols [20]. This would conduce to free out the anions to increase the nucleophilicity of the solution. 18-crown-6-ether can chelate K+ to form a metal complex (eq. 2), that may improve the nucleophilicity of the RO− anion [21]. O

O

O

O O

O

O

KOH

O K

O O

O

OH-

(2)

O

Based on the above results and consideration, ethanolamine, benzyl alcohol, KOH, DMSO, and 18-crown-6-ether were selected as the ingredients of the non-aqueous decontaminant formula. 3.1.2. Proportion optimization of the components in non-aqueous decontaminant The extreme vertices design method [22] was used to determine the optimum proportions of all the components in the non-aqueous formula. Based on the properties and function of each component, the proportion of ethanolamine should be between 50% and 80%, and those of benzyl alcohol, DMSO, 18-crown-5-ether, and KOH should be from 5% to 15%, 10% to 40%, 5% to 15%, and 2%, respectively. The limits of the proportion ranges of ethanolamine, benzyl alcohol, and DMSO are shown in Fig. 1a. Fifteen experiments were investigated to evaluate the HD decontamination efficiency by the extreme vertices design method (Fig. 1b and Table 2). The efficiency response signals of 9

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the different compositions were compiled using Minitab computer software (Fig. S1). Based on the automatically optimized signals obtained using Minitab, the optimum composition of the non-aqueous decontaminant formula was as follows: ethanolamine 50%, benzyl alcohol 9%, DMSO 28%, 18-crown-6-ether 11%, and KOH 2%. 3.1.3. Effects of decontaminant/CWA volume ratio The decontamination capacities of the non-aqueous decontaminant at various decontaminant/CWA volume ratios were evaluated. The results show that the decontamination percentage increased with increasing V[decontaminant]/V[CWA] ratio (Fig. 2). To achieve decontamination ratio >99%, the V[decontaminant]/V[CWA] for HD, GD and VX should be no less than 30, 2, and 10, respectively. 3.1.4. Effects of reaction temperature The decontamination efficiencies at various temperatures were evaluated based on CWA decomposition at constant volume ratios and a fixed vortex speed of 800 r/min. The changes in the percentage CWA decomposition are shown in Fig. 3. The decomposition ratio increased with increasing temperature. The decomposition percentages at 25 °C for HD, GD, and VX were 99.1%, 100%, and 99.2%, respectively. The results suggest that this non-aqueous decontaminant could be used to treat CWAs over a wide range of ambient temperatures, even low temperatures. The average apparent activation energy of the degradation reaction was calculated to be 9.63 kJ/mol, based on the Arrhenius equation (Table 3). This is much lower than the apparent activation energy for HD hydrolysis, which was calculated to be approximately 84 kJ/mol [23]. This shows that the nucleophilicity of the active group in the

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non-aqueous decontaminant is stronger than that of the hydroxyl anion in the aqueous system. 3.2. Degradation products and pathways 3.2.1. HD degradation products and pathways The GC/MS total ion chromatogram for the degradation products of HD is shown in Fig. 4. The main mass fragments of each product are shown; the main degradation product is chloroethyl vinyl sulfide (Table 4, No. 1). The other main products are also listed in Table 4. The detected and identified products suggest that the main HD degradation pathway is elimination of HCl (Scheme 1). Scheme 1. HD degradation pathways in non-aqueous decontaminant.

3.2.2. GD degradation products and pathways The degradation products of GD in the non-aqueous decontaminant were detected and identified using GC/MS. The main product is O-pinacolyl O-benzyl methyl phosphate (Fig. S2). The experimental results suggest that the GD degradation pathway involves P–F cleavage and a nucleophilic displacement reaction (Scheme 2). 11

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Scheme 2. GD degradation pathways in non-aqueous decontaminant.

-

3.2.3. VX degradation products and pathways The reactions involved in the degradation of VX in the non-aqueous decontaminant are similar to the reactions of the phosphorus atom in GD and the sulfur atom in HD. The products detected using GC/MS suggest that the P=O, P–C, and P–O–R bonds are stable (Table 5 and Fig. 5). The peak numbers in Fig. 5 correspond to the products listed in Table 5. The main detected and identified products are O-ethyl O-benzyl methyl phosphate, 2-(diisopropylamino)ethanethiol and some other sulfo compounds. The results indicate that the VX degradation pathways involve cleavage of the P–S bond and a nucleophilic displacement reaction to produce disulfides (Scheme 3). Scheme 3. VX degradation pathway in non-aqueous decontaminant.

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3.3. Treatment of various materials contaminated with CWAs Four materials, i.e., an military exposure suit, concrete, an iron plate, and an alkyd paint coating, contaminated with HD at an initial HD density of 20 g/m2 were treated with the non-aqueous decontaminant (Table 6). The experimental results indicate that the residual HD densities on all the samples were less than 280 mg/m2 at room temperature. The residual HD densities on concrete and the military exposure suit were 238.7 and 204.7 mg/m2, respectively. The residual HD density was lowest on the iron coupon because of its non-penetrability. The residual VX densities (the initial VX density was 5 g/m2) on all the materials were less than 24 mg/m2. No residual VX was detected on the iron coupon and those on the military exposure suit, concrete, and alkyd paint coating were 10.3, 17.8, and 4.1 mg/m2, respectively. 3.4. Causticity of decontaminants The corrosion levels of stainless steel, carbon steel, copper, and aluminum immersed in the non-aqueous decontaminant and DS-2 were investigated. The experimental results (Table

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7) show that the degrees of corrosion of the metal materials in the non-aqueous formula were lower than those in DS-2. A paint coating was seriously corroded by DS-2 (Fig. S3), but in the non-aqueous decontaminant almost no corrosion occurred in 24 h. This indicated that the non-aqueous decontaminant is better than DS-2 for practical applications. 4. Conclusions CWAs were effectively degraded using a non-aqueous decontaminant. The experimental results show that the CWA degradation efficiency increased with increasing temperature. The non-aqueous decontaminant was efficient even at low temperatures. The V[formula]/V[CWA] ratio needs to be at least 30, 2, and 10 for HD, GD, and VX, respectively, to achieve >99% decontamination. The residual amounts of HD on four materials were below the accepted standard limit after treatment using the new non-aqueous decontaminant. The identified degradation products suggest that HD was mainly degraded via elimination reactions; GD and VX were mainly degraded via nucleophilic displacement reactions. The non-aqueous decontaminant did not corrode stainless steel, copper, aluminum, carbon steel, and a low-corrosive paint coating, and could therefore be used on sensitive equipment. Acknowledgments The present research was funded by National Key Research and Development Program of China (2016YFC0801303). References (1) Snow, R. L. Deadly Cults: The Crimes of True Believers. Praeger Publishers: Westport, CT. 2003, pp.49. (2) U.S. Congress Senate, Committee on Governmental Affairs. Terrorism through the Mail: 14

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Protecting Postal Workers and the Public: Joint Hearings before the Committee on Governmental Affairs, United States Senate and the Subcommittee on International Security, Proliferation and Federal Services, One Hundred Seventh Congress, first session, October 30 and 31, 2001. Washington: U.S. G.P.O. 2002. (3) Volchek, K.; Fingas, M.; Hornof, M.; Boudreau, L.; Yanofsky, N. Decontamination in the Event of a Chemical or Biological Terrorist Attack. Protection of Civilian Infrastructure from Acts of Terrorism. Springer: Netherlands, 2006. pp. 125-145. (4) NBC Decontamination, Field Manual 3-5, Jan 2002 (Unclassified). (5) Yang, Y. C.; Baker, J. A.; Ward, J. R. Decontamination of Chemical Warfare Agents. Chem. Rev. 1992, 92, 1729-1743. (6) Singh, B.; Prasad, G. K.; Pandey, K.S.; Danikhel, R. K. Decontamination of Chemical Warfare Agents. Defense Sci. J. 2010, 60, 428-441. (7) Toepfer, H.-J. Development of a New Family of CBRN Decontaminants. Mil. Technol. 2007, 31, 102. (8) Davis, G. T.; Block, F.; Sommer, H. Z.; Epstein, J. Studies on the Destruction of Toxic Chemical Agents VX and HD by the All Purpose Decontaminants DS-2 and CD-1; Report EC-TR-75024;U. S. Army Edgewood Research Development and Engineering Center: Aberdeen Proving Ground, MD, 1975 (unclassified). (9) Haley, M. V.; Chester, N. A.; Kurnas, C. W. Aquatic Toxicity of Decontaminating Solutions DS-2/DS-2P. AD-A285920. 1994 (unclassified). (http://www.dtic.mil/docs/citations/ ADA285920) (10) Wolverton, B. C. Monoethanolamine Lithium Decontaminating Agent. U.S. Patent 3,634,278, 1972. (11) Grotta, H. M.; Nixon, J. R.; Zamejc, E. R. Development of Novel Decontamination Techniques for Chemical Agents (GB, VX, HD) Contaminated Facilities. AD-B073034. 1983 (unclassified). (http://www.dtic.mil/docs/citations/ ADB073034) (12) Boone, C. M. Present State of CBRN Decontamination Methodologies. TNO report, TNO-DV 2007 A028, TNO Defense, Netherlands, 2007 (unclassified). (13) Air Mobility Command. Large Aircraft Interior Decontamination, Foreign Comparative Test Final Report, 2000. (http://dtic.mil/descriptivesum/Y2001/OSD/stamped/0605130D8Z.pdf) (14) GD-6 Decontamination Agent (http://www.owrgroup.net/index.php?article_id=107&clang=1) 15

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(15) Qi, L. H.; Zuo, G. M.; Cheng, Z. X.; Wang, L. Y.; Zhou, C. H. Treatment of Chemical Warfare Agents by Combined Sodium Percarbonate with Tetraacetylethylenediamine Solution. Chem. Eng. J. 2013, 229, 197-205. (16) Qi, L. H.; Zuo, G. M.; Cheng, Z. X.; Zhu, H. Y.; Li, S. M., Oxidative Degradation of Chemical Warfare Agents in Water by Bleaching Powder. Water Sci. Technol. 2012, 66, 1377-1383. (17) Hao, R.-Z.; Cheng, Z.-X.; Zhu, H.-Y.; Zuo, G.-M.; Zhang, C.-M. Transportation of Sulfur Mustard (HD) in Alkyd Coatings. J. Phys. Chem. A 2007, 111, 4786−4791. (18) Metals Materials-Uniform Corrosion-Methods of Laboratory Immersion Testing. JB-T 7901-2001, China Mechanical and Industrial Bureau: Beijing, 2001. (19) Szafraniec, L.; Linda, Reactions of Chemical Warfare Agents with DS2: Product Identification by NMR II. 2-Chloroethyl Sulfides. Report ERDEC-TR-034, U. S. Army Edgewood Research. Development Engineering Center: Aberdeen Proving Ground, MD, 1993 (unclassified). (20) Parker, A. J., Protic-Dipolar Aprotic Solvent Effects on Rates of Bimolecular Reactions. Chem. Rev. 1969, 69, 1-32. (21) Casselman, A. A.; Thompson, H,G.; Bannard R. A. B. An Examination of Macrocyclic Ether-Alkali Metal Salt Complexes as Decontaminants for Chemical Warfare Agents in Non-aqueous Solvents. AD-A077516 1979. (22) Mclean, R. A.; Anderson, V. L. Extreme Vertices Design of Mixture Experiments. Technometrics 1966, 8, 447-454. (23) Bartlett, P. D.; Swain, C. G., Kinetics of Hydrolysis and Displacement Reactions of β,β’-Dichlorodiethyl Sulfide (Mustard Gas) and of β-Chloro-β’-Hydroxydiethylsulfide (Mustard Chlorohydrin). J. Am. Chem. Soc. 1949, 71, 1406-1415.

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TOC graphic

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Figure Captions Fig. 1. Experiment design by extreme vertices design method Fig. 2. The decontamination percentage after 30 min of degradation of CWAs with different volume ratios of decontaminant and CWA. Fig. 3. The decontamination percentage after 30 min of degradation of CWAs with different

temperature

at

V[decontaminant]/V[HD]=30,

V[decontaminant]/V[GD]=2,

V[decontaminant]/V[VX]=10. Fig. 4. GC/MS total ion chromatogram for the degradation products of HD in the non-aqueous formula. Fig. 5. GC/MS total ion chromatogram for the degradation products of VX in the non-aqueous formula.

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Fig. 1.

a

Ethanolamine

b

Ethanolamine

0.8

0.8

Ethanolamine 2

0.1

0.05

0.05

0.05

7

9× 12 0.35

Benzyl alcohol

0.5

0.4

DMSO

Ethanolamine 0.8

0.05

0.4

DMSO

0.1

0.5

0.35

Crown ether

0.35

Benzyl alcohol

0.5

0.35

Crown ether

Benzylalcohol

Benzyl alcohol 0.35

0.05

0.4

DMSO

3

10 15

8

4

11

5

13

14

6 1

0.1

0.05

0.35

Crown ether

2

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DMSO

Crown ether

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Fig. 2.

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Fig. 3.

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Fig. 4.

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Fig. 5.

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Table Captions Table 1. Decontamination efficiency for mixed-level orthogonal array points Table 2. Decontamination efficiency for these typical experiment points. Table 3. Decontamination efficiency of HD with different temperature. Table 4. Possible degradation products of HD identified by GC/MS. Table 5. Possible degradation products of VX identified by GC/MS. Table 6. Treatment of HD and VX contaminating on different materials. Table 7. The causticity of two formulas to metal materials

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Table 1. Decontamination efficiency for mixed-level orthogonal array points

NO.

Factors

Decontamination ratio(%)

A

B

C

1

1

1

1

39.2

2

1

2

2

62.8

3

2

1

1

47.7

4

2

2

2

63.8

5

3

1

2

36.1

6

3

2

1

63.7

7

4

1

2

39.4

8

4

2

1

63.3

K1

102

162.4

213.9

k1

51.0

40.6

53.5

K2

111.5

253.6

202.1

k2

55.8

63.4

50.5

K3

99.8

/

/

k3

49.9

/

/

K4

102.7

/

/

k4

51.4

/

/

R

5.9

22.8

3.0

j-factors; i-levels; y-results

Ki=∑yi, ki=Ki/(the number of i

R=the difference between kmax

level in factor j)

and kmin

Note: [amine]: [alcohol]= 7:3, [alkali]=1.5%, V[decontaminant]/V[CWA]=20:1,reaction time: 30min

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Table 2. Decontamination efficiency for these typical experiment points.

Points type

vertices

boundary surface center

center

ethanol-

benzyl

amine

alcohol

(%)

(%)

1

50

5

2

80

3

18-crown

vertices for the

-6-ether

boundary

(%)

surface

40

5

--

91.9

5

10

5

--

90.5

50

5

30

15

--

91.7

4

70

15

10

5

--

90.2

5

50

15

20

15

--

91.1

6

50

15

30

5

--

90.3

7

60

15

10

15

--

89.5

8

70

5

10

15

--

91.6

9

50

10

30

10

①,②,⑤,⑦

91.1

10

57.5

15

17.5

10

①,②,③,④

91.3

11

62.5

5

22.5

10

⑤,⑥,⑦,⑧

92.0

12

70

10

10

10

③,④,⑥,⑧

91.3

13

57.5

10

17.5

15

①,③,⑤,⑥

92.1

14

62.5

10

22.5

5

②,④,⑦,⑧

90.8

15

60

10

20

10

①,②,...,⑧

90.2

NO.

DMSO (%)

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Decontamination ratio (%)

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Table 3. Decontamination efficiency of HD with different temperature. Temperature

Decontamination percentage

Reaction rate

Average apparent activation

(°C)

after 30 min (%)

constant k (min-1)

energy Ea (kJ/mol)

5

95.8

0.044

15

98.0

0.060

25

99.1

0.062

35

99.4

0.068

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9.63

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Table 4. Possible degradation products of HD identified by GC/MS. NO.

Name

Proposed molecular structure

1

2-Chloroethyl vinyl-sulfide

2

1,2-bis(vinylthio)-ethane

3

Divinyl sulfide

4

N-(2-hydroxyethyl)-thiomorpholine

5

(2-Vinylsulfanyl-ethoxymethyl)-benzene

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Table 5. Possible degradation products of VX identified by GC/MS NO.

Name

Proposed molecular structure

1

2-(Diisopropylamino)-ethanethiol

2

O-ethyl-O-benzyl-methylphosphate

3

Bis(2-diisopropylaminoethyl) sulfide

4

Bis(diisopropylaminoethyl) disulfide

5

1-[(2-diisopropylamino)ethylthio]2-[(2-diisopropylamino)ethyldithio]-Ethane

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Table 6. Treatment of HD and VX contaminating on different materials.

Materials

Total residues (μg)

Density of the residues (mg/m2)

HD

VX

HD

VX

exposure suit

625.9

32.7

204.7

10.3

concrete

734.7

54.1

238.7

17.8

iron plates

1.9

0.4

0.2

0

alkyd paint coat

115.1

12.6

27.7

4.1

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Table 7. The causticity of two formulas to metal materials

Materials Stainless steel

corrosive degree

R(mm/a) DS-2

this formula

DS-2

this formula

0.006

0.001

basic non-corrosive

non-corrosive

Carbon steel (A3)

0.026

0.003

slightly-corrosive

non-corrosive

Copper (H62)

0.014

0.003

slightly-corrosive

non-corrosive

Aluminum (LV13)

0.381

0.010

moderately-corrosive

basic non-corrosive

(1Cr18Ni9Ti)

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