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Chemical reactions of chlorovinylarsines (Lewisite)
3. Reaction of Lewisite I and Lewisite II with Dithiols
Rainer Haas
Buero fuer Altlastenerkundung und Umweltforschung, Stadtwaldstrasse 45a, D-35037 Marburg, Germany
Translation, original article was published in UWSF - Z Umweltchem. Oekotox. 10 (4) 198 - 199 (1998), ecomed publishers D-86899 Landsberg, Germany
Abstract
Chemical Reactions of chlorovinylarsines (Lewisite)
3. Reaction of Lewisite I and Lewisite II with dithiols
2-Chlorovinylarsine dichloride (Lewisite I) and 2,2'-dichlorodivinylarsine chloride (Lewisite II) react by room temperature rapidly and quantitatively with dithiols in a substitution reaction. The derivatives were identified with mass spectrometry. They can be detected with GC/ECD. This reactions can be used for the gas chromatographic detection of Lewisites in water and soil samples.
Key words: analysis, arsenical compounds, chemical warfare agents, cwa, chemical reactions, chlorovinylarsine dichloride, dichlorodivinylarsine chloride, lewisite
1 Experimental
2-Chlorovinylarsine dichloride, Lewisite I (CAS-No. 541-25-3) and 2,2-Dichlorodivinylarsine chloride, Lewisite II (CAS-No. 40334-69-8) were derivatizied with the following dithiols: 1,2-Ethane dithiol (Et(SH)2), 1,3-Propane dithiol (Pr(SH)2), 1,4-Butane dithiol (Bu(SH)2), 1,5-Pentane dithiol (Pe(SH)2), 1,6-Hexane dithiol (He(SH)2) and 1,8-Octane dithiol (Oc(SH)2). For the derivatizations acetonic solutions containing 76 µg/ml Lewisite 1, 70 µg/ml Lewisite 2 and 400 µg/ml dithiol were used. Derivatizations were done in 1.4 ml vials by the temperature of 20°C.
For the separation of the Lewisite derivatives a gas chromatograph HP 5890 with HP 7673 autosampler and electron capture detector (ECD) was used. Analysis were done under the following chromatographic conditions:
column: capillary column DB 5, length 30 m, thickness 0.25 mm
carrier gas: nitrogen
column temperature: initial 100°C (1 min), 10°C/min to 230°C, 230°C (6 min)
injector temperature: 250°C
detector temperature: 300°C
injection volume: 1 µl.
Three minutes after adding of dithiols analysis were started and repeated during next three weeks. Identification of the derivatives was done by gas chromatography mass spectrometry (GC/MS).
2 Results and discussion
2-Chlorovinylarsine dichloride reacts with dithiols in a substitution reaction like
Cl(CH=CH)AsCl2 + HSRSH --> Cl(CH=CH)AsS2R + 2 HCl
by creating stable cyclic derivatives.
2,2-Dichlorodivinylarsine chloride reacts upon dithiols like
(Cl(CH=CH))2AsCl + HSRSH --> (Cl(CH=CH))2AsSRSH + HCl
by creating 2,2-Dichlorodivinylarsindithiolthioether.
There are retention times (Rt) and limits of detection (LOD) of all derivatives presented in table 1.
Table 1: Retention times (Rt) and limits of detection (LOD) for lewisite and their derivatives; (chromatographic conditions see experimental.) L1: Cl(CH=CH)As; L2: (Cl(CH=CH)2)As
compound |
Rt/min |
LOD/ng |
L1-Cl2 |
nn |
nn |
L1-S2Et |
10,60 |
0,2 |
L1-S2Pr |
12,02 |
0,3 |
L1-S2Bu |
13,62 |
1,0 |
L1-S2Pe |
15,04 |
1,0 |
L1-S2He |
16,38 |
1,0 |
L1-S2Oc |
19,85 |
1,0 |
L2-Cl |
7,06 |
0,35 |
L2-SEtSH |
14,21 |
0,3 |
L2-SPrSH |
15,60 |
0,3 |
L2-SBuSH |
17,16 |
0,8 |
L2-SPeSH |
19,02 |
0,8 |
L2-SHeSH |
21,36 |
1,1 |
L2-SOcSH |
28,31 |
1,7 |
The derivatization is completed during 30 min by 20°C. The retention time of the derivatives depends on the molecular weight. The LOD differ between 0.2 and 1.0 ng for Lewisite 1 derivatives and between 0.3 and 1.7 ng for Lewisite 2 derivatives. The least LOD were found for the EtSH2 derivatives, the highest for the OcSH2 derivatives.
All derivatives are stable in reaction solution by 4°C for more than three weeks. it was not possible to determine the reaction rates for Lewisite 1 because lewisite 1 could not be detected by gas chromatography. The derivatization of Lewisite 2 to cyclic derivatives is quantitative.
Experiments with equimolar amounts of two dithiols were done. The percentage part of both dithiol derivatives is shown in table 2.
Table 2: Percentage part of the Lewisite 1 and Lewisite 2 dithiol derivatives
thiol 1 |
thiol 2 |
derivative 1 |
derivative 2 |
derivate 1 |
derivative 2 |
|
|
Lewisite 1 |
Lewisite 1 |
Lewisite 2 |
Lewisite 2 |
Et(SH)2 |
Pr(SH)2 |
99 |
1 |
64 |
36 |
Et(SH)2 |
Bu(SH)2 |
99 |
1 |
69 |
31 |
Et(SH)2 |
Pe(SH)2 |
99 |
1 |
70 |
30 |
Et(SH)2 |
He(SH)2 |
100 |
0 |
78 |
22 |
Et(SH)2 |
Oc(SH)2 |
100 |
0 |
75 |
25 |
Pr(SH)2 |
Bu(SH)2 |
98 |
2 |
65 |
35 |
Pr(SH)2 |
Pe(SH)2 |
99 |
1 |
52 |
48 |
Pr(SH)2 |
He(SH)2 |
99 |
1 |
48 |
52 |
Pr(SH)2 |
Oc(SH)2 |
99 |
1 |
60 |
40 |
Bu(SH)2 |
Pe(SH)2 |
46 |
54 |
58 |
42 |
Bu(SH)2 |
He(SH)2 |
63 |
37 |
49 |
51 |
Bu(SH)2 |
Oc(SH)2 |
71 |
29 |
45 |
55 |
Pe(SH)2 |
He(SH)2 |
55 |
45 |
53 |
47 |
Pe(SH)2 |
Oc(SH)2 |
63 |
37 |
63 |
37 |
He(SH)2 |
Oc(SH)2 |
60 |
40 |
63 |
37 |
EtSH |
Et(SH)2 |
1 |
99 |
52 |
48 |
PrSH |
Pr(SH)2 |
2 |
98 |
58 |
42 |
With Lewisite 1 cyclic derivatives were created. Five and six ring structures are the most stable ring systems. They were created with Et(SH)2 and Pr(SH)2. In mixtures with Et(SH)2 or Pr(SH)2 and additional higher dithols 98-100% of 5-ring or 6-ring derivatives were created.
With the Lewisite 2 derivatives such selection was not obeseved, because no cyclic derivatives were obtained.
This reaction type can be used as derivatization method for the analytical determination of Lewisite 1 and Lewisite 2 and their hydrolysis and oxidation products.
3 Literature
[1] Haas, R.; Schmidt, T.C. (1997): Chemische Reaktionen von Phenylarsinverbindungen. 3. Reaktion von Phenyl-Arsen-Verbindungen mit Dithiolen. UWSF-Z. Umweltchem. Ökotox. 9, 183-184
[2] Haas, R. (1998): Gas Chromatographic detection of Chemical Warfare Agents. Gas Chromatographic analysis of Ethylarsine dichloride by derivatization with dithiols. ESPR-Environ. Sci. & Poll. Res. in print
[3] Haas, R. (1997): Chemische Reaktionen von Phenylarsinverbindungen. 2. Reaktion von Diphenylarsinverbindungen mit Dithiolen. UWSF Z. Umweltchem. Ökotox. 9, 123-124
[4] Haas, R.; Schmidt, T.C.; Steinbach, K.; v. Löw, E. (1997): Gaschromatographische Bestimmung von Arsenkampfstoffen und Umwandlungsprodukten. Fachtagung Rüstungsaltlasten (Grundwassersanierung), Munster 7./8.10.97