Document KRjDno2pj8aJEqYENL0oYwL00

Characterization of the Components of Technically Polychlorinated Biphenyl Mixtures--II by A. C. Tas nd R. J. C. Kleipool Control Institute for Nutrition and Food Rettarch TNO Zeiit--The Netherlandi Three more components of technically polychlorinated biphenyl mixtures (PCB) have been unequivocally identified. Introduction The contamination of the environment by polychlori nated biphenyls (PCB) and the occurrence of these products in wildlife (1-^), and even human tissues induced us to identify the exact structure of the major components of these mixtures and to synthesize them in a pure form in order to make toxicity studies possible. In Figure 1 the gaschromatogram of a batch of the technical product Phenochlor DP6 is shown, other batches and trade products showing only minor differences (2, 5). Gaschromatogram of Phenochlor DP6. Column: glass, 1.9 m x 3 mm i.d., packed with OV-1 on gaschrom. Q, 80-100 mesh, temp. l80C, flow 60 ml Ng/min. Detection: electron capture Bulletin of Knvfiohn>entat Contamination t ToTkolofy, Vo), I, No. 1, 1912 (T) by $prio|ei-WrU| New York Ine, 52 DSW 031167 STLCOPCB4015129 inated r;tified. ^ioriroducts s to 3 Of m in Bhe - ches 5). - niri. .A.*. Recently we published the structure and the synthesis of the components, indicated in the gas- chromatogram as peak numbers 6, 8. 11 and 12 (5). The products proved to be 2,2',4,4',5,5'-hexachloro- biphenyl, 2,2' ,3,4 ' ,5 '-hexachlorobiphenyl, 2,2' 5,5'-heptachlorobiphenyl and 2,2*, 3, 3* ,4,l\' ,5-heptachlorobiphenyl, respectively. The very strong absorption at 813 cm" in the IR spectrum of the PCB suggested that still other products with an 1,2,3,4-substitution pattern in the benzene nuclei could be present among the unin- dentified peaks. In that case the chlorine atoms are possibly attached to the 2,3 and 6 positions. On synthesis of some of these products we succeeded in the identification of: 2,2',3,3',6,6'-hexachlorobiphenyl (I) 2,2',3,*i',5',6-heptachlorobiphenyl (II) 2,2' ,3,3' ,* ,5,6'-heptachlorobiphenyl (III) as the main components of peak numbers 3, 5 and 10 respectively. Syntheses of these compounds were per formed by the Ullmann reaction, starting with the appropriate polychloroiodobenzenes (6) which were in turn synthesized from commercially available products by known methods. Identification was established by IR spectra and by the retention times on three different GLC columns of both the components isolated from the PCB mixture, and the synthesized compounds, where as the NMR spectra of the synthetic products gave Experimental IR spectra were recorded with a Hilger and Watts H-1200 apparatus. Absorptions are given in cm"*. NMR spectra were recorded with a Jeol A60 apparatus, CHClj being the internal standard and CClij being the solvent. Chemical shifts are given in ppm relative to TMS. Control GLC was carried out by using: 1. a Carlo Erba Fractovap GV apparatus, supplied with either of the following glass columns: a - 1.9 m x 3 mm i.d., packed with J>% OV-1 on faschrom. Q, 80-100 mesh, temp. 180C, flow 0 ml Ng/min. b - 1.9 m x 3 mm i.d., packed with 1.OV-1 and 2.1% QF-1 on gaschrom. Q, 80-100 mesh, temp. l80C, flow 60 ml N^/min. S3 DSW 031168 STLCOPCB4015130 2. a Microtek MT 220 gaschromatograph supplied with Ni-63 EC -detector and a glass column 6** x 1/4", packed with 3X DEGS (stabilized) ' on gaschrom. Q,- 80-100 mesh, temp. 190C, flow 75 ml Ar with 10? methane/min. Reten tion times are given, relative to aldrin. Preparative GLC was carried out by using an Aerograph A-90-P apparatus. Column:stainless steel 2mx5mmi.d., packed with 20? SE-30 on chromo- sorb W/AW, temp. 240C, flow 60 ml Hp/min. The mass spectrum was recorded with an Atlas CH5 apparatus using the direct inlet system. Syntheses 2.5- dichloro-4~-nltracetanilide and 2,5-dichloro- t>-nitracetanilide . " 2,5-Dichloroaniline was acetylated and nitrated according to the directions of Holleman and Van Haeften (7). A mixture of approximately 80? 2,5-dichloro-4-nitracetanilide and 20? 2,5- dichloro-6-nitracetanilide was obtained. On re crystallization of this mixture from ethanol a considerable quantity of nearly pure 2,5-dichloro- 4-nitracetanilide crystallized out. Further puri fication was performed by a repetition of the same procedure. From the filtrate a mixture of both isomers in a ratio of approximately 1:1 (IR) was obtained. Three extractions at room temperature with hpnKPTlP * in wViT^'h - 1- P- n..r.p...o.r t c nwr*O --.v^ enom-- *'*nOf--rln soluble, and one recrystallization from the same solvent yielded 2 jS-dichlo'ro-G-nitracetanilide in a pure form. 2.4.5-trichloroiodobenzene and 2,3,6-trichloro- iodobenzene.--------------------------------------- -------------------------- Of the appropriate 2,5-dichloronitracetanilide 3 g (0.012 moles) were heated for 45 min. in 15 g of 98? sulphuric acid at 95-100oC (7).After cooling the mixture was poured on cracked ice, while being stirred, and the 2,5-dichloronitraniline was filtered off and washed with water. The crude aniline was suspended in 35 ml of concentrated hydrochloric acid and treated dropwise with O.85 g (0.012 moles) of sodium nitrite in 2 ml of water at 20~35C. Under these conditions the nitro-group of both isomers was replaced by a chlorine atom, while the diazonium-group remained intact (7,8,9). After stirring for 45 min. at 25"30C, the diazo nium solution was filtered and cooled to -50C. At this temperature 2*g (0.012 moles) of potassium- iodide in 10 ml of water was added dropwise. The reaction mixture was extracted twice with ether, washed with water and sodiumthiosulphate and finally dried over sodiumsulphate. DSW 031169 STLCOPCB4015131 .3 an steel DJDO^las ro- ---an -y _ oro_^i- . IR) :h ay ^ in -5lide -5 g oling >eing 35 6 -er ^roup .9). jzosium7re - IV'-* After removal of the Bolvent and recrystallitation from ethanol 2,2-2,4 g (60-66$) of the pro duct was obtained. The IR apectrum and the physical constants of 2,^,5-trichloroiodobenzene have been described formerly (5). 2,3,6-trlchloroiodobenzene. Mw: 306; three Cl" ait oms (from mass spectrum) Mp: 35-36C Bp: 88-91C, 0.5 mm IR Bpectrum: Figure 2. 3000 3000 1800 1600 U00 1300 1000 600 cm-1 IR spectrum of 2,3>6-trichloroiodobenzene (liquid film) 2,3*J,5-tetrachloroiodobenzene haB also been des cribed in our first paper (5). The appropriate polychloroiodobenzenes were heated with 10$ more than the equal quantity of activated copper powder at 215-225C with occasion al stirring for 2} hr (10). After cooling the re action mixture was extracted five times with boiling hexane. The solvent being removed, the polychlorobiphenyls were purified by preparative GLC. I. 2,2',3,3*,6,6* hexachlorobiphenyl as the only product from 2,3,6-trichjLoroioclobenzene Mp: lUJ-ll1)^0^ (from ethanol) Rt value cf Ion la 2.08; on lb 2.07; on 2 3.33 of peak no 3cn la 2.09; on lb 2.06; on 2 3.33 IR spectrum: Figure 3A NMR spectrum: 6= 7.^9 (2,d,J=8.5 cps) and =737 (2,d,J=8.5 cps) 35 DSW 031170 STLCOPCB4015132 f -r1* v. II 2,2' ,3* ,5' ,6-hexachlorobiphenyl as the major product'from an 1:1 mixture or 2 ,'3,6- and 2,4,5 .. trichloroiodobenzenes. Could not be obtained in a crystalline form. Rt value of II on la 2.58; on lb 2.59; on 2 3.89 of peak no. 5 on la 2.57; on lb 2.59; on 2 3.89 'IR spectrum: Figure 3B NMR spectrum 6 =7.64 (l,s); 6=7.48 (l,d,J= 8.5 cps) 6(l=,7s.3)6 (l,d,J=8-5 cps) and 6= 7.30 Byproducts: I (see afore) and 2,2' 4,4 ' ,55,-hexachlorobiphenyl, formerly described (5). IR spectra of (A) 2,2*>3>3`,6,6'-hexachlorobiphenyl (I) (supercooled film); (B) 2,2',3, 4',5',6-hexachlorobiphenyl (II) (liquid film); fc): 2.2 ',3,3' ,4 ,5,6 '-heptachlorobiphenyl (III) (supercooled film) 36 DSW 031171 STLCOPCB4015133 VMbl or -,5- .69 .69 30 jnexa- irrtWV ~* iVi.^ III 2,2,f3,3,f*i ,5,6'-heptachlorobiphenyl as the major reaction product from an 1:3 mixture of , 2,3,6-trichloroiodobenzene and 2,3,^,5-tetrachloroiodobenzene. Mp: 130.5-130-.7C (from ethanol) Rt value of III on la 5*25; on lb 5.22; on 2 6.90 of peak no. 10 on la 5.25; on lb 5.20; on 2 6.89 IR 8pectrum: Figure 3C NMR spectrum: 6=7-50 (l,d,J=8.5 cps); 6=7.38 (l,d,J=8.5 cps) and 6=7.27 (1,6) Byproducts: I (see afore) and 2,21,3,3',4',5, 5'-octachlorobiphenyl, formerly described (5). References 1. JENSEN, S., New Sci. 32, 612 (1966) 2. KOEMAN, J.H., TEN NOEVER DE BRAUW, M.C. and DE VOS, R.H., Nature 221, 1126 (1969) 3. HOLDEN, A.V., Nature 228, 1220 (1970) it. BIROZ, F.J., WALKER, A.C. and MEDBERY, A., Bull. Environ. Contain. Toxicol. 5, 317 (1970) 5. TAS, A.C. and DE VOS, R.H., Environ. Sci Technol., in the press 6. BACHMANN, W.E. and HOFFMAN,R.A.Organic Reactions, Vol. 2, 2^3, Wiley, London (19^6) 7. HOLLEMAN, A.F. and TEN HAEFTEN, F.E., Rec. Trav. Chi m. Ufl, 60 (IQPl) 8. DEY, B.B., GOVINDACHARI, T.R. and RAJAGOPALAN, S.C., Current Sci 15, 161 (19^6) 9. DEY, B.B., KRISHNA MALLER, R. and PAI, B.R., J. Sci. Ind. Res. (India) 10B, ljU, 1*10 (1951) 10. ORGANIC SYNTHESIS, Coll. Vol. 3, 339 Acknowledgements We gladly acknowledge R.H. de Vos and the colla borators of the pesticides department of our Institute for the gaschromatographic control measurements and R.Belz for his valuable suggestions and discussions. S7 DSW 031172 STLCOPCB4015134