(3) Peake, E., Baker, B. L., Hodgson, G . W., Geochim. Cosmochirn. Acta, 36,867 (1972). (4) Morris, J. C., in “Principles and Applications of Water Chemistry’’, Faust, S.D., and Hunter, J. V., Eds., p 23, Wiley, New York, N.Y., 1967. (5) Kovacic, P., Lowery, M. K., Field, K. W., Chem. Reu., 70, 639 (1970). (6) Langheld, K., Chem. Ber., 42,2360 (1909). (7) Dakin, H., Cohen, J. B., Danfresne, M., Kenyon, J., Proc. R. Soc. London, Ser. B, 89,232 (1916). (8) Dakin. H.. Biochem. J.. 11.79 (1917). (9) Wright, N. C., Biochek J.: 30,’1661’(1936). (10) Fox, S.W.. Bullock. M. W., J. Am. Chem. Soc.. 73, 2754 (1951). (11) Ingols, R. S., Wyckoff, H. A., Kethley, T. W., Hodgden, H. W., Fincher, E. L., Webrand, J. C. H., Mandel, J. E., Ind. Eng. Chem., 45,996 (1953). (12) Pereira, W. E., Hoyand, Y., Summons, R. E., Bacon, V. A., Duffield, A. M., Biochim. Biophys. Acta, 313,170 (1973). (13) Metcalf, W. S., J. Chem. SOC.,148 (1942). (14) Weil, I., Morris, C. J., J . Am. Chern. Soc., 71,1664 (1949). (15) Weil, I., Morris, C. J., J. Am. Chem. Soc., 71,3123 (1949). (16) Czech, F. W., Fuchs, R. J., Antczak, H. F., Anal. Chem., 33,705 (1961). (17) Kleinberg, J., Tecotzky, M., Audrieth, L. F., Anal. Chem., 26, 1388 (1954). (18) Nikol’skii, B. P., Krunchak, V. G., L’vova, T. V., Pal’chevskii,
V. V., Susnovskii, R. I., Dokl. Phys. Chem. (Eng2.Trawl.), 191,343
(1970). (19) Kantouch, A,, Abdel-Fattah, S. H., Chem. Zuesti, 25, 222 (1971). (20) Stankovic, L., Chem. Zuesti, 14,275 (1960). (21) Stankovic, L., Vasatko, J., Chem. Zuesti, 14,434 (1960). (22) “Standard Methods for the Examination of Water and Wastes”, 13th ed., American Public Health Association, Washington, D.C., 1971. (23) Strickland, J. D. H., Parsons, T. R., “A Practical Handbook of Seawater Analysis”, Bulletin 167,2nd ed., Fisheries Research Board of Canada, Ottawa, 1972. (24) Margerison, D., in “Comprehensive Chemical Kinetics”, Bamford, C. H., and Tipper, C. F. H., Eds., Vol. 1,Elsevier,Amsterdam, 1969. (25) “Handbook of Chemistry and Physics”, 55th ed., Chemical Rubber Company, Cleveland, Ohio, 1974-1975. (26) March, J., “Advanced Organic Chemistry: Reactions, Mechanisms, and Structure”, McGraw-Hill, New York, N.Y., 1968. (27) Brown, B. R.. 9.Reu. Chek. Soc., 5,131 (1951). (28) Hamming,R.’W.,“Introduction to Applied Numerical Analysis”, McGraw-Hill, New York, N.Y., 1971. (29) Marquardt, D. W., J . SOC.Ind. Appl. Math., 11,431 (1963). Received for review April 7, 1978. Accepted October 31, 1978. This work was supported by the State of Maryland Power Plant Siting Program.
Reactions of Organic Pollutants. 1. Ozonation of Acenaphthylene and Acenaphthene Paul N. Chen, Gregor A. Junk”, and Harry J. Svec Department of Chemistry and Ames Laboratory-US.
Department of Energy, Iowa State University, Ames, Iowa 5001 1
reported here from three different solvent systems, hexane,
The polyaromatic hydrocarbons, acenaphthylene (1) and methanol, and water, help t o clarify the ozonation reaction acenaphthene (2), were ozonated separately in hexane (HI, products and the mechanisms leading to their formation. This in methanol (M), and in water (W). T h e reaction products clarification is intended to supplement the fundamental were separated and identified by packed column gas chromatography, combination gas chromatography/mass spectrometry, and NMR and IR spectroscopy. The major products from the ozonation of 1 in the three solvent systems were: 1,8-naphthalenedialdehyde(H, M, W); l&naphthalene anhydride (H, M, W); methyl 8-formyl-1-naphthoate (M); dimethoxyacetal 1,8-naphthalenedialdehyde(M); 1,2-epoxyacenaphthylene (W); 1-naphthoic acid (W); and 1,8naphthaldehydic acid (W). T h e major products from the ozM, W); methyl onation of 2 were: 7-formyl-1-indanone (H, 1-indanone-7-carboxylate(M); 1-indanone (M, W); 7-hydroxy-1-indanone (M, W); 1-indanone-7-carboxylic acid (W); indane-1,7-dicarboxylic acid (W); and indane-l-formyl-7carboxylic acid (W). Reaction pathways are proposed for some of these identified products.
Many organic pollutants which occur in the aquatic environment are refractory but most are altered by traditional water treatment methods using permanganate, chlorine, and/or ozone. Therefore, unidentified environmental problems may exist because the products from these chemical processes are generally unknown. For this reason, a program has been initiated here to study the organic reaction products from treatment methods used in water processing. Ozonation reactions were chosen for the initial studies with the target chemicals being acenaphthylene and acenaphthene. Previous investigations of these two chemicals by others ( I , 2 ) had not included solvent effects, in situ conditions, and the reaction products in water. The results 0013-936X/79/0913-0451$01.00/0
@
1979 American Chemical Society
knowledge concerning ozonation reactions and to be coupled with future results to: (a) list the potential pollutants caused by ozonation of various waters; (b) predict t h e most probable products in water based on the ozonation of water-insoluble organic compounds in hexane and in methanol.
Experimental T h e operating conditions were standardized for all the ozonation reactions. An OREC Model 03V9-0 laboratory ozonator was used to supply 4% ozone at a n oxygen flow of 0.6 L/min through the solutions. Excess 0 3 was used in all reactions. Infrared spectra were measured in CDC13 with a Beckman IR-20AX spectrophotometer. Proton magnetic resonance spectra were measured with a Varian HA-100, 100-MHz instrument. Mass spectra were obtained with a DuPont 21-490-1 gas chromatograph/mass spectrometer (GC/MS) and a n AEI MS-902 high-resolution mass spectrometer. All gas chromatographic separations were made isothermally using a Varian 1200 GC equipped with a flame ionization detector, 3 m m 0.d. X 3 m stainless steel columns packed with either 4% FFAP or 5% OV-1 on acid-washed SO/lOO mesh Chromosorb W and a He flow of 35 mL/min. Preparative GC separations were accomplished using a Varian Autoprep lOOA equipped with a thermal conductivity detector, a 7 mm 0.d. X 4 m glass column packed with 5% OV-1 on acid-washed SO/lOO mesh Chromosorb W, and a He flow of 140 mL/min. All solvents were redistilled from reagent grade material. The distilled water used in these experiments was free of detectable organic matter. Volume 13, Number 4, April 1979
451
Acenaphthylene [I]
t
1
03 in Y 2 0
I
Filter, Et20 extraction f
Et23 layer
Aqueous layer 3t20 extraction r
Aqueous layer
E t 2 $ layer
(discard) 9
I
COOH
ECl (pH=3)
7
8
Flgure 1. Products from ozonation of acenaphthylene (1) in hexane (H), in methanol (M), and in water (W) Results a n d Discussion
Ozonation of Acenaphthylene (1). The final products isolated and identified after the ozonation of acenaphthylene in various solvent systems are shown in Figure 1. For simplicity, no mechanisms or intermediates are shown but these are discussed when appropriate in the following sections dealing with the results from the separate solvent systems. I n Hexane. Hexane was a nonparticipating solvent in the ozonation of acenaphthylene. The characteristic yellow color of the solution disappeared within 10 min after the start of the ozonation and a white solid believed to be the ozonide was formed ( 3 ) .This white solid disappeared after standing 1week a t room temperature. The final products, 1,8-naphthalenedialdehyde (3) and l&naphthalene anhydride (4), were identified by GC/MS. The mass spectrum for compound 3 was consistent with the dialdehyde structure with prominent peaks [m/z (relative intensity)] a t 184 (M+, 79), 183 (19), 156 (43), 155 (97), 128 (49), 127 (loo), and 77 (14).The peakat (M - 1)and the loss of CO and CHO to form ions a t 156,155,128, and 127 are characteristic of an aromatic aldehyde. The anhydride 4 was confirmed by comparison of the GC/MS data with that of an authentic sample. I n Methanol. Methanol is a participating solvent in the ozonation of acenaphthylene. Methyl 8-formyl-1-naphthoate ( 5 ) and dimethoxyacetal 1,8-naphthalenedialdehyde(6) in addition to products 3 and 4 were identified. Preparative gas chromatography was employed to isolate about 5 mg of the white crystalline product 5. This material melted a t 99-101 "C (lit. 102-104 "C) ( 4 ) .Its NMR spectrum in CDCl3 showed six aromatic protons from 6 8.64 to 7.54, one benzylic proton a t 6.44, and a signal for the methoxy protons a t 3.72 ppm. The IR spectrum in CDC13 showed intense carbonyl stretching at 1730 cm-l. The high-resolution mass spectrum showed a molecular ion a t 214.0623 (calcd 214.0630 for CI3Hl0O3).The low-resolution mass spectrum showed prominent peaks at 214 (M+, 27), 213 (16), 186 (37), 183 (loo), 155 (74), 127 (75), 126 (77),and 77 (14). All these instrumental data aye consistent with the identification of the product. The pathway proposed for the formation of 5 is given by Reaction Sequence 1:
Aqueous layer (discard)
(A-2)
I
CH2N2
('4-31 Flgure 2. Liquid-liquid extraction of products from oronation of acenaphthylene (1) in water
tautomerism ( 4 ) to form a lactone-hemiacetal intermediate (lo), which subsequently forms the lactone-methoxyacetal ( 5 ) by reaction with the methanol solvent. The existence of the dialdehyde 3 as a hydrated dihemiacetal (3') has been suggested by Stille and Foster (6). Therefore, the identification of the dimethoxyacetal(6) was not surprising because the rationale for its formation is the pathway shown in Reaction Sequence 2:
3
3'
where trace amounts of H20 present in the methanol participate in the hydration. The mass spectrum of product 6 with prominent peaks at 230 (M+, 14),299 (12), 199 (55), 171 (lOO), 169 (17), and 141 (21) was consistent with the assigned structure. The loss of H or CH30 from the molecular ion is typical for the proposed benzylic acetal structure. I n Water. The results for the ozonation of acenaphthylene in hexane and methanol were used as a guideline for the investigation of the ozonation reaction in water. A suspension of acenaphthylene was reacted for 5 h in water at 60 OC, the unreacted material was filtered, and the products were extracted from the aqueous solution according to the scheme shown in Figure 2. From an interpretation of GC/MS data, the dialdehyde 3 and a small amount of 1,2-epoxyacenaphthylene (7)were identified in fraction A-1. Compound 3, the anhydride 4,and 1-naphthoic acid (8) were found in fraction A-2. Also found in this fraction was a more stable isomeric form (7) of product 7, 1-oxoacenaphthylene (1 l ) , probably produced according to Reaction 3 during the base/acid extraction. The assigned
9-9 0 7
1
0-0
HOOC CHO II
where the solvent-activated decomposition of the ozonide (3, 5 ) intermediate to the aldehydic acid is followed by ring-chain 452
Environmental Science & Technology
6
(3)
0 II
structures of products 7 and 11 were based on their mass spectral fragmentation patterns. The epoxide 7 gave prominent peaks at 168 (M+, loo), 152 (8),and 139 (24). The loss of oxygen from the molecular ion to form an acenaphthylene cation a t m/z 152 is consistent with the assigned structure 7. The oxo compound, 11, showed the loss of CO and CHO from the molecular ion with prominent peaks a t 168 (M+, 95), 140 (loo), and 139 (60).
Table 1. Products, Identification Methods, and Yields for Ozonations of Acenaphthylene (1) reaction solvent
product
1&naphthalenedialdehyde (3) l&naphthalene anhydride (4)
3 4 methyl 8-formyl-1-naphthoate(5) dimethoxyacetal 1,8-naphthaIenedialdehyde (6)
3 4 1,2-epoxyacenaphthyIene (7) 1-naphthoic acid (8) l&naphthalic acid (9) l&naphthaldehydic acid (10) a
Compared with authentic sample.
ldentlflcation method
hexane hexane methanol methanol methanol methanol water water water water water water
yield, %
GCIMS GC/MSa GCa GCIMS GC/MS,a GCa GCIMS, IR, NMR, mp GCIMS GCIMS GCIMS,a GCa GCIMS GC/MS,a GCa GCIMS GCIMS
35
35 12 4 43
20 37 5 1
8 5 20
Based on identification of the methyl ester derivative.
The identification of the monoacid 8 was established from a comparison of the CX/MS data with that of an authentic sample. The observation of anhydride 4 is explainable on the basis of the known dehydration of phthalic acid to phthalic anhydride (8) in the injection port of the G U M S instrument under conditions used for the GC separation of the components in fraction A-2. Therefore, the anhydride 4 is probably formed through the dehydration in the GC injection port of the corresponding l&naphthalic acid (9) produced by the ozonation of acenaphthylene in water. The methoxyacetal (5) and the dimethyl ester of the diacid, 9, were identified in fraction A-3. These observations confirm that 110th the diacid 9 and the hemiacetal 10 were products of the ozonation in water. A summary of the identification methods and yields for all the ozonation products of acenaphthylene (1) is given in Table I. Ozonation of Acenaphthene (2). The products isolated and identified after the ozonation of acenaphthene in various solvent systems are shown in Figure 3. Again, for simplicity, the reaction mechanisms and intermediates are not listed but are discussed when necessary in sections dealing with results in various solvents. In Hexane. The ozonation of acenaphthene in hexane gave a white crystalline product assumed to be the ozonide ( 3 ) , which decomposed in situ to a single product. Based on interpretation of GC/MS data, this product was identified as 7-formyl-1-indanone (12). This compound had previously been reported ( 2 )to be the major product when acenaphthene was ozonated in methanol. Preparative GC was used to isolate about 5 mg of 12 and its NMR spectrum was taken in CDCl:{. A n aldehydic proton signal a t 6 11.1, three aromatic protons a t 8.0--7.7, and two sets of multiplets with two protons each at 3.3 and 2.8 ppm were observed. The IR spectrum of 12 in CDCI:] showed intense carbonyl stretching a t 1710 cm-1. Its mass spectrum showed prominent peaks a t 160 (M+,28), 1 3 2 (100). 131 (22), 104 (83),103 (99),78 (271, and 77 (27). These losses of CO and CHO from the molecular ion are consist,ent with the assigned structure. In Methanol. The products of ozonation of acenaphthene i n methanol were identified from GC/MS data to be compound 12, methyl 1-indanone-7-carboxylate (13), 1-indanone (141, and 7-hydroxy-l -indanone (15). The identifications of products 14 and 15 were further confirmed by comparison of their CX/MS data wit,h those of authentic samples. About 5 mg of the methyl ester 13 was isolated by preparative GC and the NMR spectrum in CDC1:3 was obtained. Three aromatic
m OHC 0 12
pw 1"
0 14
\w
HOOC CHO
HO 0
i
18
w w
H O O C COOH
15
HOOC 0
17 16 Figure 3. Products from ozonation of acenaphthene (2) in hexane (H), in methanol (M), and in water (W)
protons at 6 7.7-7.4, a methoxy signal a t 4.0, and two sets of multiplets with two protons each a t 3.2 and 2.7 pprn were observed. The IR spectrum in CDC1 showed intense carbonyl stretching a t 1715 cm-I. The mass spectrum showed prominent peaks at 190 (M+,291,175 (321, 159 (loo), 132 (34), 131 (221, 104 (241, 103 (291, and 77 (20). The losses of CH1 and CH from the molecular ion are consistent with the assigned methyl ester structure. Callighan et al. (2) reported a yield of 7% for the 1-indanone-7-carboxylic acid (16) after ozonation of acenaphthene in methanol. However, no ester 13 was reported. We observe the methyl ester to he a major product and we have also identified the aldehyde 12 as a minor product of the ozonation. From these results, a pathway for the formation of 12 and 13 is proposed in Reaction Sequence 4:
/
19
I
-
0:cti 0 '
' c 00 ti
19'
,o ti/c'coo
CHJOOC
HO-
ti
0
13
19"
where the primary ozonation product 19 reacted with O,{to form an intermediate which decomposed to 12 and which formed the diradical 19'. The rearranged form, 19", of this diradical then reacted with the methanol solvent to form the Volume 13, Number 4, April 1979
453
Table II. Products, Identification Methods, and Yields for Ozonations of Acenaphthene (2) reaction solvent
produci
7-formyl- 1-indanone (12) 12 methyl 1-indanone-7-carboxylate (13) 1-indanone (14) 7-hydroxy-1-indanone (15) 12 14 15 1-indanone-7-carboxylic acid (16) indane-l,7dicarboxylic acid (17) indane-1-formyl-7-carboxylic acid (18) a
Compared with authentic sample.
hexane methanol methanol methanol methanol water water water water water water
yield, %
GCIMS, IR, NMR GCIMS, IR, NMR GCIMS, IR, NMR GCIMS, a GC a GCIMS, a GC a GCIMS, IR, NMR GCIMS,a GCa GCa GUMS GCIMS GCIMS
80
13 60
6 6 25 1 1 30
5
5
Based on identification of the methyl ester derivative.
methyl ester 13. The trace amounts of 1-indanone (14) and 7-hydroxy-lindanone (15) were probably formed by a reaction pathway involving free-radical or zwitterion intermediates. In Water. Acenaphthene was ozonated in water using procedures identical with those described for acenaphthylene and the reaction products were extracted in the same way as shown in Figure 2. Three fractions, B-1, B-2, and B-3, were collected and they correspond to fractions A-1, A-2, and A-3, respectively. From an interpretation of the GC/MS data, compounds 12 and 14 were identified in fraction B-1. Three other acidic products in addition to the identified compound 15 were obtained in fraction B-2, 1-indanone-7-carboxylic acid (16), indane-1,7-dicarboxylic acid (17), and indane-l-formyl-7carboxylic acid (18). These three acids were identified as their methyl esters in fraction B-3 after reaction with diazomethane to produce methyl 1-indanone-7-carboxylate(13), dimethylindane-1,7-dicarboxylate(20), and methylindane-l-formyl-7-carboxylate (21), respectively. The mass spectrum of compound 20 showed prominent peaks a t 234 (M+, 60), 219 (40), and 203 (100) which is consistent with this identification. The mass spectrum of compound 21 showed peaks a t 204 (M+, 5 ) , 176 (loo), 173 (99), 161 (85), 145 (66), 118 (45), and 89 (77). The possibility that the functional groups might be interchanged in compound 2 1 was ruled out because of the absence of a (M - 1)peak in the mass spectrum which would be observed if a benzaldehydic grouping was present. Because of the low yield, confirmation of these two esters, 20 and 21, by additional instrumental measurements was not attempted. A summary of the identification methods and the yields for all the ozonation products of acenaphthene is given in Table 11. The yield data in this table and in Table I for acenaphthylene show that most of the ozonation products in all three solvent systems have been identified. Conclusions
The results of the studies of the ozonations of polyaromatic hydrocarbons (PAH) in hexane and in methanol where sufficient amounts of the products are available for definitive instrumental analyses are definite aids to the ozonation studies in water, where limited solubility restricts severely the amounts of the products formed. Future results with other PAH and other insoluble organic compounds in multiple solvent systems will have to be accumulated to increase the reliability of predicting the products of the ozonations in water. Fundamental knowledge of the ozonation mechanisms is 454
ideniificaiion method
Environmental Science & Technology
necessary since not all products such as 3,4,8,9, 17, and 18 are normal. Others, such as 7, 10, 12, 14, 15, and 16, are abnormal and require nontraditional mechanisms to explain their formation. This conclusion is verified by recent results reported by Shapiro et al. (IO),where an abnormal mechanism had to be invoked to explain the formation of alkanes during the ozonation of domestic wastewater. The unsaturated linkages present in this water should have produced only aldehydes, ketones, and acids (11). The chemical structures of all the identified products suggest enhanced biodegradability due to incorporation of oxygen into the PAH system. None of the products appear to possess unusual toxicity, but this conclusion is offered with guarded optimism. Unknowns which must be considered are the possible chronic toxicity and the probable reaction of the ozonation products with the trace amounts of unreacted pollutants. Acknowledgment
We thank Drs. J. S. Fritz, G. A. Russell, and W. S. Trahanovsky for their interest, Norbert Morales, Mike Avery, and Ray Vick for their instrumental assistance, and A. S. Lee who prepared the 7-hydroxy-1-indanone (9). Literature Cited (1) Callighan, R. H., Tarker, M. F., Jr., Wilt, M. H., J . Org. Chem., 26,1379 (1961). (2) Callighan, R. H., Tarker, M. F., ,Jr., Wilt, M. H., J . Org. Chem., 27,765 (1962). (3) Criegee, R., Korher, H., Adv. Chem. Ser., No. 112, 22 (1972). (4) Bowden. K.. Last. A. M.. J . Chem. S o c . Perkin Trans. 2. 1144 (1973). (5) Ellam, R. M., Padhury, J . M., Chem. Commun., 1094 (1971). (6) Stille, J. K., Foster, R. T., J . Org. Chem., 28,2703 (1963). ( 7 ) Kinstle, T. H., Ihrig, P. J., J . Org. Chem., 35,257 (1970). ( 8 ) Junk, G. A., Chen, P. N., Ames Laboratory-USDOE, Iowa State University, Ames, Iowa, unpublished data, 1977. (9) Wagatsuma, S.,Higuchi, S.,Ito, H., Nakano, T., Sakai, K., Matsui, T., Takahashi, Y., Nishi, A., Sano, S., Org. Prep. Proced. Int., 5,65 (1973). (10) Shapiro, R. H., Kolonko, K. J., Binder, R. T., Barkley, R. M., Eiceman, G. A,, Haack, L. P., Sievers, R. E., in “Proceedings of 4th Joint Conference on Sensing Environmental Pollutants”, p p 507-10, American Chemical Society, Washington, D.C., 1978. (11) Sievers. R. E., Barkley, R. M., Eiceman, G. A,, Shapiro, R. H., Walton, H. F., Kolonko, K. J., Field, L. R., J . Chromatogr., 142,745 (1977).
Receiued for ret,iew April 3, 1978. Accepted October 31, 1978. T h i s research was supported by National Science Foundation Grant No. CHE75-21,502. The G C I M S was ohtained under Grant N O GP93526X. Other instruments used in this uork u’ere purchased by ICJUU State L‘nioersity u,ith matching funds from the N S F . T h e facilities of the Ames Laboratory, U S . Department of Energy, u‘ere used with support by the Dicisions of Basic Energy Science and Riomedical and Encironmental Research.
