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Chlorinated alkylbenzenes in C12 chlorinated paraffins
Chemoephere Vol. 9, )P 119 - 142 OPer~on
0045-6535/0301-0139~02.00/0
Press Ltd. 1980. ~ i n t e d in G~eat ~ i t & i n
CHLORINATED ALKYLBENZENES IN C12 CHLORINATED PARAFFINS V. Zitko Fisheries and Environmental Sciences Department of Fisheries and Oceans Biological Station, St. Andrews, N.B. EOG 2XO Canada Alkylbenzenes C12H14 and ClIHI6 in a concentration of about I% were identified in a C12 paraffin stock used for the preparation of chlorinated paraffin 500C (Diamond Shamrock Corporation). Evidence was obtained that some chlorinated alkylbenzenes are present in the chlorinated paraffin 500C. Chlorinated paraffins are used mainly as additives in plastics, paints, and some l u b r i cating oils [1,2]. Recent reports indicate that, in contrast to C24 chlorinated paraffins [ 3 ] , C12 chlorinated paraffins are toxic to, and are accumulated by, fish [4,5]. I t appears that this difference in the properties of chlorinated paraffins is primarily due to the difference in molecular weight. Since the content of aron~atic hydrocarbons in paraffinic stocks used for the preparation of chlorinated paraffins was correlated recently with b l a s t ~ g e n i c a c t i v i t y of the l a t t e r [ 6 ] , i t was of interest to characterize these aromatic hydrocarbons in greater detail. MATERIALS AND METHODS The C12 paraffin stock, Exxon Paraffin C12, and the chlorinated paraffin 50(IC (59% Cl mol. wt. 415) were a g i f t from the Diamond Shamrock Corporation. Both materials were analyzed by GCMSon a Finnigan Model 1015 mass spectrometer coupled to a Finnigan Model 9000 gas chromatograph equipped with a 2 m x 0.2 cm glass column containing 3% 0V-I01 on Chromosorb W 80/100. Injector and separator were maintained at 250 and 300°C, respectively. Column te,~erature was increased from I00 to 200°C at a rate of 8°C/min. Mass spectra were scanned from m/z-50 to 500 every 3 sec. UV spectra were recorded on a Beckman DK-2A spectrophotometer. The chlorinated paraffin 500C was fractionated by solvent partitioning as described previously [7]. RESULTS AND DISCUSSION Paraffin stock. The main straight chain paraffins are CI0-C14, in a relative proportion of 22, 36, 37, and 5%. UV absorption maxima at 265 and 271 nm indicate the presence of alkylbenzenes. The absorbance at 265 nm corresponds to 1.33% of alkylbenzenes in the stock, expressed as 1,2,3,4tetramethylbenzene. GCMS indicates the presence of at least I~ alkylbenzenes, mostly CIOH14, and some 1H)6: From the frag~ntation pattern§ i t appears that the CIOH14 hydrocarbons are primarily lecnym- ano methyl~iso-propyloenzenes (prominent M-15 ion), and ~thym-n-propylbenzenes prominent M-2g i o n ) ~ e main C11H16 hydrocarbons appear to be ethyl-n'~propylbenzenes and dim~thyl-n-propylbenzenes. The content of alkylbenzenes calculated fro~ the intensity of the m/z 119 i~ns is 0.7%, expressed as 1,2,3,4-tetramethylbenzene.
i~
139
140
Chlorinated paraffin 500C. The reconstructed gas chromatogram consists of six major, partly resolved peaks, and several minor peaks (Fig. I ) . Molecular ions were generally not detectable in the mass spectra and ions formed by the loss of HCl (M-36) were usually the highest m/z ions in the spectra (Table I ) . Subsequent fragmentation patterns consisted of further losses of HCI and CI. I t is l i k e l y that the olefins indicated in Table 1 were formed from the respective paraffins by loss of HCI either in the chromatograph or in the spectrometer. Table 1 Components of chlorinated paraffin 500C identified by GCMS Scan no.
m/z (C135)
142 148
206 152 206 185 220 274 290 282 304 324 338 358 372
167 188 206
223 238 *~1orlnated
Assignment
CIoH17C13 ClllHllCl 3 ClOH17C13 ClOHIoCl 4 C11H19cl 3 ClOH15C15 C11H19C15 C11Hll C15 C12H21C15 CllH18 C16 C12H20C16 CllH17 C17 C12H19C17
- 36 - 84 (35+49)* -
36
- 85 (36+49)* -36 -36 -36 -
36*
-36 - 36 -
36
-
36
-
36
alkylbenzene
R~
Fig. 1.
Reconstructed gas chromatogram of chlorinatec~ paraffin 50(0).
141
The search for chlorinated alkylbenzenes is complicated by their r e l a t i v e l y low abundance in the chlorinated paraffin preparation, low intensity of molecular ions caused by the f a c i l e 8-elimination of the alkyl chains as the prevailing fra~nentation mechanism, and potential interference by fragment ions of chlorinated paraffins, which is impossible to eliminate in low resolution mass spectrometry. Three chlorinated alkylbenzenes were tentatively identified (Table 1) and the mass spectrum leading to the identification of CIOH11Cl3 is given in Fig. 2. 8 14B--144 l~I~
>126 X 6
6
Fig. 2.
Mass spectrum of compounds el uting in peak ÷
number 148. Arrow indicates the ion CgHgCII (m/z)=152, presumably formed from CIOH11C13. Cluster at m/z-206 was assigned to CIoH16Cl~ and CIOHI7CI~, formed from CIOHI7Cl3 or CIoH18Cl4. An attempt to isolate a fraction enriched in chlorinated alkylbenzenes by solvent partitioning of 500C was unsuccessful. After partitioning between hexane and DMSO, 5% (fraction I ) of 500C remained in hexane. The bulk of the preparation (94%) was extracted from 50% aqueous DMSOwith hexane (fraction 2), and an additional 1% (fraction 3) was extracted with diethylether. UV absorbance of fraction 3 was negligible when corrected for DMSOblank and UV absorbances of fractions I and 2 did not indicate any significant enrichment of chlorinated alkylbenzenes. Conclusions. C4- and C5-alkylbenzenes are present in a C12 stock used for the preparation of chlorinated paraffins and chlorinated alkylbenzenes were tentatively identified in a chlorinated paraffin preparation. The materials analyzed may be a f a i r l y typical example of commercial products, although i t has been reported that some European paraffin stocks undergo a special treatment to lower the content of aromatic hydrocarbons to 50-100 pg/g [8]. The toxicological and environmental significance of the presence of chlorinated alkylbenzenes in chlorinated paraffins cannot be assessed at this time. The reported correlation between blastomogenicity and aromatic hydrocarbon content [ 6 ] emphasizes the need for further studies. ACKNOWLEDGMENTS Mr. Jack A. Borror (Diamond Shamrock Corporation) provided the samples. Drs. K. Haya and S. Ray commented on the manuscript. Brenda McCullough typed the manuscript and Messrs. P.W.G. McMullon and F.B. Cunningham prepared the figures. Ms. R. Garnett assisted on editorial matters.
142
REFERENCES
i. O. Svanberg, and E. Linden.
A~nblo 8, 206 (1979).
2. V. Zitko. Chlorinated Paraffins. Springer Verlag, in press. 3. V. Zltko.
Handbook of Environmental Chemistry, O. Hutzlnger, Editor,
Bull. Environ. Contam. Toxlcol. 12, 406 {1974).
4. O. Svanberg, B.-E. Bengtson, E. Linden, G. Lu~e, and E. Baumann Ofstad.
~ b i o ~, 64 (1978).
5. B.-E. BenSson, O. Svanberg, E. Llnd~n, G. Lunde, and E. Baumann Ofstad.
~Io
6. B. A. Kurlyandskll, N. I. Nevzorova, F. D. ~shblts, and M. B. ~llna.
8, 121 (1979).
Gig. Sanlt. 68 (197g).
7. V. Zltko, and E. Arsenault. Fate of high molecular weight chlorinated paraffins in the aquatic environment, in: Advances in Environmental Science and Technology, Vol. 8.2, I.H. Suffet, Editor, Wiley-lntersclence 1977, p. 40%418. 8. J. F. D. Mills.
Personal Communication, ICl ~ n d Division 197g.
(~eceived in The ~etharlaadJ 19 7ebruzT 1980)
0045-6535/0301-0139~02.00/0
Press Ltd. 1980. ~ i n t e d in G~eat ~ i t & i n
CHLORINATED ALKYLBENZENES IN C12 CHLORINATED PARAFFINS V. Zitko Fisheries and Environmental Sciences Department of Fisheries and Oceans Biological Station, St. Andrews, N.B. EOG 2XO Canada Alkylbenzenes C12H14 and ClIHI6 in a concentration of about I% were identified in a C12 paraffin stock used for the preparation of chlorinated paraffin 500C (Diamond Shamrock Corporation). Evidence was obtained that some chlorinated alkylbenzenes are present in the chlorinated paraffin 500C. Chlorinated paraffins are used mainly as additives in plastics, paints, and some l u b r i cating oils [1,2]. Recent reports indicate that, in contrast to C24 chlorinated paraffins [ 3 ] , C12 chlorinated paraffins are toxic to, and are accumulated by, fish [4,5]. I t appears that this difference in the properties of chlorinated paraffins is primarily due to the difference in molecular weight. Since the content of aron~atic hydrocarbons in paraffinic stocks used for the preparation of chlorinated paraffins was correlated recently with b l a s t ~ g e n i c a c t i v i t y of the l a t t e r [ 6 ] , i t was of interest to characterize these aromatic hydrocarbons in greater detail. MATERIALS AND METHODS The C12 paraffin stock, Exxon Paraffin C12, and the chlorinated paraffin 50(IC (59% Cl mol. wt. 415) were a g i f t from the Diamond Shamrock Corporation. Both materials were analyzed by GCMSon a Finnigan Model 1015 mass spectrometer coupled to a Finnigan Model 9000 gas chromatograph equipped with a 2 m x 0.2 cm glass column containing 3% 0V-I01 on Chromosorb W 80/100. Injector and separator were maintained at 250 and 300°C, respectively. Column te,~erature was increased from I00 to 200°C at a rate of 8°C/min. Mass spectra were scanned from m/z-50 to 500 every 3 sec. UV spectra were recorded on a Beckman DK-2A spectrophotometer. The chlorinated paraffin 500C was fractionated by solvent partitioning as described previously [7]. RESULTS AND DISCUSSION Paraffin stock. The main straight chain paraffins are CI0-C14, in a relative proportion of 22, 36, 37, and 5%. UV absorption maxima at 265 and 271 nm indicate the presence of alkylbenzenes. The absorbance at 265 nm corresponds to 1.33% of alkylbenzenes in the stock, expressed as 1,2,3,4tetramethylbenzene. GCMS indicates the presence of at least I~ alkylbenzenes, mostly CIOH14, and some 1H)6: From the frag~ntation pattern§ i t appears that the CIOH14 hydrocarbons are primarily lecnym- ano methyl~iso-propyloenzenes (prominent M-15 ion), and ~thym-n-propylbenzenes prominent M-2g i o n ) ~ e main C11H16 hydrocarbons appear to be ethyl-n'~propylbenzenes and dim~thyl-n-propylbenzenes. The content of alkylbenzenes calculated fro~ the intensity of the m/z 119 i~ns is 0.7%, expressed as 1,2,3,4-tetramethylbenzene.
i~
139
140
Chlorinated paraffin 500C. The reconstructed gas chromatogram consists of six major, partly resolved peaks, and several minor peaks (Fig. I ) . Molecular ions were generally not detectable in the mass spectra and ions formed by the loss of HCl (M-36) were usually the highest m/z ions in the spectra (Table I ) . Subsequent fragmentation patterns consisted of further losses of HCI and CI. I t is l i k e l y that the olefins indicated in Table 1 were formed from the respective paraffins by loss of HCI either in the chromatograph or in the spectrometer. Table 1 Components of chlorinated paraffin 500C identified by GCMS Scan no.
m/z (C135)
142 148
206 152 206 185 220 274 290 282 304 324 338 358 372
167 188 206
223 238 *~1orlnated
Assignment
CIoH17C13 ClllHllCl 3 ClOH17C13 ClOHIoCl 4 C11H19cl 3 ClOH15C15 C11H19C15 C11Hll C15 C12H21C15 CllH18 C16 C12H20C16 CllH17 C17 C12H19C17
- 36 - 84 (35+49)* -
36
- 85 (36+49)* -36 -36 -36 -
36*
-36 - 36 -
36
-
36
-
36
alkylbenzene
R~
Fig. 1.
Reconstructed gas chromatogram of chlorinatec~ paraffin 50(0).
141
The search for chlorinated alkylbenzenes is complicated by their r e l a t i v e l y low abundance in the chlorinated paraffin preparation, low intensity of molecular ions caused by the f a c i l e 8-elimination of the alkyl chains as the prevailing fra~nentation mechanism, and potential interference by fragment ions of chlorinated paraffins, which is impossible to eliminate in low resolution mass spectrometry. Three chlorinated alkylbenzenes were tentatively identified (Table 1) and the mass spectrum leading to the identification of CIOH11Cl3 is given in Fig. 2. 8 14B--144 l~I~
>126 X 6
6
Fig. 2.
Mass spectrum of compounds el uting in peak ÷
number 148. Arrow indicates the ion CgHgCII (m/z)=152, presumably formed from CIOH11C13. Cluster at m/z-206 was assigned to CIoH16Cl~ and CIOHI7CI~, formed from CIOHI7Cl3 or CIoH18Cl4. An attempt to isolate a fraction enriched in chlorinated alkylbenzenes by solvent partitioning of 500C was unsuccessful. After partitioning between hexane and DMSO, 5% (fraction I ) of 500C remained in hexane. The bulk of the preparation (94%) was extracted from 50% aqueous DMSOwith hexane (fraction 2), and an additional 1% (fraction 3) was extracted with diethylether. UV absorbance of fraction 3 was negligible when corrected for DMSOblank and UV absorbances of fractions I and 2 did not indicate any significant enrichment of chlorinated alkylbenzenes. Conclusions. C4- and C5-alkylbenzenes are present in a C12 stock used for the preparation of chlorinated paraffins and chlorinated alkylbenzenes were tentatively identified in a chlorinated paraffin preparation. The materials analyzed may be a f a i r l y typical example of commercial products, although i t has been reported that some European paraffin stocks undergo a special treatment to lower the content of aromatic hydrocarbons to 50-100 pg/g [8]. The toxicological and environmental significance of the presence of chlorinated alkylbenzenes in chlorinated paraffins cannot be assessed at this time. The reported correlation between blastomogenicity and aromatic hydrocarbon content [ 6 ] emphasizes the need for further studies. ACKNOWLEDGMENTS Mr. Jack A. Borror (Diamond Shamrock Corporation) provided the samples. Drs. K. Haya and S. Ray commented on the manuscript. Brenda McCullough typed the manuscript and Messrs. P.W.G. McMullon and F.B. Cunningham prepared the figures. Ms. R. Garnett assisted on editorial matters.
142
REFERENCES
i. O. Svanberg, and E. Linden.
A~nblo 8, 206 (1979).
2. V. Zitko. Chlorinated Paraffins. Springer Verlag, in press. 3. V. Zltko.
Handbook of Environmental Chemistry, O. Hutzlnger, Editor,
Bull. Environ. Contam. Toxlcol. 12, 406 {1974).
4. O. Svanberg, B.-E. Bengtson, E. Linden, G. Lu~e, and E. Baumann Ofstad.
~ b i o ~, 64 (1978).
5. B.-E. BenSson, O. Svanberg, E. Llnd~n, G. Lunde, and E. Baumann Ofstad.
~Io
6. B. A. Kurlyandskll, N. I. Nevzorova, F. D. ~shblts, and M. B. ~llna.
8, 121 (1979).
Gig. Sanlt. 68 (197g).
7. V. Zltko, and E. Arsenault. Fate of high molecular weight chlorinated paraffins in the aquatic environment, in: Advances in Environmental Science and Technology, Vol. 8.2, I.H. Suffet, Editor, Wiley-lntersclence 1977, p. 40%418. 8. J. F. D. Mills.
Personal Communication, ICl ~ n d Division 197g.
(~eceived in The ~etharlaadJ 19 7ebruzT 1980)