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NOTES 3-Methyl-2-benzothiazolinone Acetone Azine with 2-Phenylphenol as a Solid Passive Monitoring Reagent for Ozone Jack L. Lambert* and Joseph V. Paukstelis Department of Chemistry, Kansas State University, Manhattan, Kansas 66506
Yuan C. Chlang Department of Chemistry, Kansas Wesleyan University, Salina, Kansas 6740 1
rn 3-Methyl-2-benzothiazolinone acetone azine and 2phenylphenol in 1:4 molar solid mixture reacts specifically with ozone at concentrations of environmental interest to produce a red-violet color. The response is proportional, but not rectilinearly, to ozone concentration at constant exposure time and to time of exposure at constant ozone concentration. The reagent is intended for use with visual comparison standards in passive monitoring devices. No interference was observed from atmospheric oxygen, nitrogen dioxide, sulfur dioxide, or bromine or iodine vapor. Chlorine produced a light yellow color.
Introduction In a continuing study of solid reagents for ozone, tin(11)-diphenylcarbazide was the first reported as a visual colorimetric reagent responsive to both ozone and nitrogen dioxide (I,2), which are the strong oxidants of concern as atmospheric pollutants. Phenoxazine was reported as a solid reagent selective for ozone (3). It produced a dull brown color with ozone, but it also produced a visually distinct red-orange color with nitrogen dioxide. Surgi and Hodgeson ( 4 ) reported lO,lO’-dimethyl-9,9’-biacridylidine in a silicone-polycarbonate copolymer as a solid reagent in which the orange reagent is decolorized to N-methylacridone by reaction with ozone. In the study reported free base (MBTH) and here, 3-methyl-2-benzothiazolinone its ketone derivatives in solid mixture with aromatic hydroxy compounds were observed to react with ozone, but only the ketone derivatives produced reagents specific for ozone. Reflection absorbance values were determined with a double-beam spectrophotometer modified for reflectance measurements to demonstrate reproducibility. In practice, the reagents are intended for visual comparison to prepared color standards. The normal application would involve constant exposure times for the reagent on an inert support such as filter paper. Experimental Section Preparation of Test Reagent. All reagents were the purest commercially available grade, and deionized water was used throughout the preparation. The synthesis was a modification of the Hunig and Fritsch method for the preparation of MBTH-formaldehyde condensation product (5). 3-Methyl-2-benzothiazolinone hydrazone hydrochloride (Aidrich), 4.0 g, was dissolved in 200 mL of water with stirring and the free base precipitated by the addition of 10 mL of concentrated ammonium hydroxide solution. The crystalline product was filtered with suction and 0013-936X/89/0923-0241$01.50/0
washed until the wash water no longer tested alkaline with pH indicator paper. The solid product was then vacuum dried at room temperature and dissolved with vigorous shaking in 100 mL of absolute ethanol in a 250-mL round-bottom flask. To this solution were added 20 mL of acetone and 10 mL of glacial acetic acid, and the solution was refluxed over a boiling water bath for 0.5 h. After the solution was cooled to room temperature, the slow addition of 300 mL of water produced a white product which was filtered and dried at room temperature. The mass spectrum of the product was consistent with 3-methyl-2benzothiazolinone acetone azine, and the yield was nearly theoretical. The product was sufficiently pure for use, but it may be further purified by recrystallization from cyclohexanol. Whatman No. 1filter paper circles, 4.25-cm diameter, were soaked for 20 min in 50.0 mL of an acetone solution acetone containing 1.10 g of 3-methyl-2-benzothiazolinone azine (0.005mol) and 3.40 g of 2-phenylphenol(O.O2mol), drained of excess solution to near dryness, dried for 20 min on a clean glass plate, and stored in a sealed container. Reflectance Spectrophotometer. The term reflection absorbance has been used for measurements made with a Perkin-Elmer Model 124 visible-ultraviolet spectrophotometer modified for reflectance measurements on reagents supported on filter paper (1-3, 6-8). The reflectance attachment was similar to the microspecular reflectance attachment described by Wendlandt and Hecht (9). The incident beam in this instrument was deflected onto a sample surface and back again to the same path to the photomultiplier tube. Loss of incident radiant energy at 535 nm was read as absorbance in the regular manner. Exposure Vessel. An inverted Kimble low-form, capstyle 50-mm-i.d. weighting bottle was modified by sealing 5-mm-i.d. tubing through the bottom as previously described (2). In the vessel used in this study, the inlet tube was bent to direct the flow of ozone onto the center of the enclosed reagent paper for convenience of reflectance measurement instead of to the side as previously constructed. Insofar as possible, all tubing that carried reactive gas mixtures was borosilicate glass or poly(tetrafluoroethylene) tubing. Glass-to-glass connections were made with Fisher and Porter Teflon seals with O-rings. Ozone Generator. A McMillan Model 1000 ozone generator (Columbia Scientific Industries Corp., Austin, TX) was calibrated iodometrically by the method of Flamm (IO). Interference Tests. The tests for interference with nitrogen dioxide were done at the ppm level in an air dilution system with permeation tubes. The tests for re-
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Figure 1. Reagent response at 535 nm to various exposure times at 1.00 ppm ozone concentration. The average, mean, and standard deviation for seven determinations at each time of exposure are shown.
activity with sulfur dioxide, bromine vapor, iodine vapor, and chlorine were qualitative. Results and Discussion Nonlinear response curves similar to those previously obtained with supported solid reagents were obtained. Reflection absorbance values at 535 nm were plotted against a fixed ozone concentration of 1.00 ppm at various exposure times (Figure 1)and against various ozone concentrations at a fixed exposure time of 500 s (Figure 2). The reflection measurements demonstrate the reproducibility of the method. The intended use for reagents in passive monitoring devices of this type would involve visual comparison to permanent color standards. The reagent papers were stable on storage, and the color produced by ozone is stable to light. As water is not involved in the reaction, no humectant was required and relative humidity was not a factor in the color development. A study of reagent reactivity vs mole ratio showed that a 1:5 or 1:6 mole ratio of MBTH acetone azine to 2-phenylphenol was the most sensitive mixture, but a 1:4 ratio was selected because of a very faint pink tinge present in 2-phenylphenol that contributed to a slight blank. This color in 2-phenylphenol is not involved in the reagent reaction with ozone. Two other MBTH ketone azines, MBTH cyclohexanone azine and MBTH 4-phenylcyclohexanone azine, were synthesized and found to react in the same manner as MBTH acetone azine. However, no particular advantage was observed with their use, and problems were encountered in dissolving sufficient quantities of the azines and 2-phenylphenolto produce practical reagents. An attempt was made to incorporate both reagent components into one compound by synthesizing the MBTH ketone azine of 2-hydroxyacetophenone, but this compound did not respond to ozone. 2-Phenylphenol was the most satisfactory of a number of aromatic hydroxy compounds studied from the standpoints of reactivity of the reagent produced, the color of the reaction product with ozone, and mutual solubility with MBTH acetone azine in the acetone solvent. 1-Naphthol and 2-naphthol with MBTH acetone azine both responded to ozone and to nitrogen dioxide. Simple phenol deriva242
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Figure 2. Reagent response at 535 nm to various ozone concentrations at 500-9 exposure tlme. The average, range, and standard deviation for six determinations at each ozone concentration are shown.
tives such as 0-,m-, and p-cresols produced orange to red colors. 3- and 4-phenylphenolswere not as sensitive in the reagent mixture as 2-phenylphenol. 2,6-Diphenylphenol was unsatisfactory (splotchy color), probably due to solubility problems. 4-Phenylphenol and 2,2’-dihydroxydiphenyl produced blue to blue-violet colors. Reagent mixtures of 2,4-dimethylphenol, 3,4-dimethylphenol, and 2,4,6-trimethylphenolwith MBTH acetone azine were not sensitive to ozone, but 2,6-dimethylphenol produced an orange color with ozone. 2,6-Dimethoxyphenol as the second component in the reagent mixture produced a red-orange color with ozone, while 3,5-dimethoxyphenol in the reagent mixture resulted in reactivity for both ozone and nitrogen dioxide. The reaction of the reagent mixture with ozone thus appears to require both an available ortho or para position on the phenol ring and a ring substituent or substituents that properly control ring reactivity. The response of the reagent mixture probably involves the attack of ozone on one of the components, followed by a coupling reaction to produce the red-violet chromogen. There was virtually no reaction observed under conditions of laboratory lighting by nitrogen dioxide on the MBTH acetone azine/2-phenylphenolreagent. Qualitative interference tests with bromine vapor, iodine vapor, and sulfur dioxide were negative. Chlorine produced a light yellow color. Registry No. 3-methyl-2-benzothiazolinone hydrazone hydrochloride, 4338-98-1; acetone, 67-64-1; 3-methyl-2-benzothiazolinone acetone azine, 53338-83-3;2-phenylphenol, 90-43-7; ozone, 10028-15-6.
Literature Cited (1) Lambert, J. L.; Beyad, M. H.; Paukstelis, J. V.; Chiang, Y. C. Anal. Lett. 1981, 14, 663. (2) Lambert, J. L.; Beyad, M. H.; Paukstelis, J. V.; Chejlava, M. J.; Chiang, Y. C. Anal. Chem. 1982,54, 1227. (3) Lambert, J. L.; Liaw, Y.-L.; Paukstelis, J . V. Enuiron. Sci. Technol. 1987, 21, 503. (4) Surgi, M . R.; Hodgeson, J . A. Anal. Chem. 1985,57,1737. (5) Hunig, S.; Fritsch, K. H. Justus Liebigs Ann. Chem. 1957, 609, 172. (6) Lambert, J. L.; Paukstelis, J. V.; Liaw, Y.-L.; Chiang, Y. C. Anal. Lett. 1984, 17, 1987.
Environ. Sci. Technol. 1989, 23, 243-244
Lambert, J. L.; Trump, E. L.; Paukstelis, J. V. Environ. Sci. Technol. 1987,21, 497. Lambert, J. L.; Liaw, Y.-L.; Paukstelis, J. V.; Chiang, Y. C. Environ. Sci. Technol. 1987, 21, 500. Wendlandt, W. W.; Hecht, H. G. Reflectance Spectroscopy; Interscience: New York, 1966; p 124.
(10) Flamm, D. L. Environ. Sci. Technol. 1977, 11, 978.
Received for review November 30,1987. Accepted August 1,1988. This research was supported in part by National Science Foundation Grant CHE-8311011.
Product Formation from the Gas-Phase Reactions of the OH Radical with (CH,O),PS and (CH30)2P(S)SCH3 Roger Atkinson," Sara M. Aschmann, Janet Arey, Patricia A. McElroy, and Arthur M. Winer
Statewide Air Pollution Research Center, University of California, Riverside, California 92521 were generated, at concentrations of (3-5) X lo7molecule ~ m - by ~ ,the photolysis of methyl nitrite in air, CH30 + NO CH30N0 + hv CH30 O2 HCHO H 0 2 HO2 + NO NO2 OH and NO was added to the reactant mixtures to avoid the formation of O3 and NO3 radicals. The initial reactant concentrations were as follows: (CH30)3PSor (CH30),P~; (when (S)SCH3, -2.4 X 1013 molecule ~ m - CH30N0 present), -2.4 X 1014molecule ~ m -and ~ ; NO, -2.4 X 1014 molecule ~ m - ~ Experiments . were carried out in a 6400-L all-Teflon chamber, equipped with black-light irradiation, at 296 f 2 K and -740 Torr total pressure of pure dry air Introduction (10). Irradiations were carried out at 50% of the maximum light intensity, with irradiation times of 2 and 4 min. Organophosphorus compounds containing the thiophosphoryl (P=S) bond, including demeton, diazinon, Gas samples of 100 cm3 were collected prior to and during the irradiations on Tenax GC solid adsorbent malathion, parathion, and phorate, are widely used insecticides in agricultural operations (1). Laboratory and (60/80 mesh) cartridges for analyses by gas chromatogambient air data have shown that for parathion and certain raphy with flame-ionization detection (GC-FID) and comother organophosphorus compounds containing the thiobined gas chromatography-mass spectrometry (GC-MS). phosphoryl bond, reaction occurs rapidly under atmosQuantitative GC-FID analyses were carried out by therpheric or simulated atmospheric conditions to transform mally desorbing the samples collected on Tenax solid adthe thiophosphoryl bond into a phosphoryl (P=O) bond sorbent at -525 K onto the head of a 15-m DB-5 Mega(2-5). Furthermore, the available evidence (2) suggests bore column (0.5-mm diameter, J&W Associates, Inc.) held that this conversion of parathion [p-o2NC6H40P(S)- at 273 K. The column was then temperature programmed from 273 to 473 K at 8 K m i d . Semiquantitative GC-MS after (OCzHs)2]to paraoxon [p-02NC6H40P(0)(OC2Hs)2] application of parathion occurs in the vapor phase. analyses also utilized thermal desorption of Tenax solid Recently, we have investigated the kinetics of the poadsorbent samples in the injection port of a Hewletttentially atmospherically important gas-phase reactions Packard 5890 GC, with cold trapping onto the head of an of a series of simple organophosphorus compounds (6-9) -40 m X 0.2 mm diameter cross-linked 5% phenylmethyl and have shown that for the trimethyl phosphorothioates silicone capillary column (Hewlett-Packard) at liquid nithe only significant atmospheric gas-phase chemical loss trogen temperature. The column was temperature proprocess is by reaction with the OH radical (6, 7,9), with grammed to 373 K at 20 K min-l and then at 10 K min-' no reaction being observed with the NO3 radical or 03. to 523 K while the HP 5970A Mass Selective Detector was From the kinetic data obtained, the majority (-85%) of in the scanning mode (40-400 amu). the OH radical reactions with O,O,O-trimethyl phosphoTrimethyl phosphate [ (CH30),PO] was obtained from rothioate [ (CH30),PS] and O,O,S-trimethyl phosphorothe Aldrich Chemical Co. and used as received. (CH3dithioate [(CH30)2P(S)SCH3]were postulated to occur by O),PS, (CH30)2P(S)SCH3,and (CH30)zP(0)SCH3were initial OH radical addition to the thiophosphoryl bond, available from our previous synthesis (7). These (CH3with the remainder occurring by H atom abstraction from O)3PS and (CH30)2P(S)SCH3 reactants contained small the C-H bonds of the CH30 or CH3S substituent groups amounts of (CH30)3P0(-7%) and (CH30)zP(0)SCH3 (-l%),respectively. Methyl nitrite was prepared as de(7). In this work, we have investigated the products formed scribed by Taylor et al. (11) and stored at 77 K under from the gas-phase OH radical initiated reactions, in the vacuum. presence of NO, of (CH30)3PSand (CH30)2P(S)SCH3, Results and Discussion with the major goal being to determine whether or not the corresponding +P=O compounds are formed from the A series of CH,ONO-NO-air and NO-air irradiations +P=S reactants and, if so, in what yield. of (CH,O),PS and (CH30)2P(S)SCH3were carried out. In the CHsONO-NO-air irradiations, the GC-FID analyses Experimental Section showed that up to -60% of the initially present (CH3The experimental methods used were generally similar O)3PSand (CH30)2P(S)SCH3 reacted and that (CH,O),PO to those used in our kinetic studies (7). Hydroxyl radicals and (CH30)2P(0)SCH3, respectively, were formed. This The products of the gas-phase reactions of the OH radical with (CH30)3PSand (CH30)2P(S)SCH3 have been investigated at room temperature and 1 atm air by gas chromatography and combined gas chromatrography-mass spectrometry. The only products observed from these reactions were (CH30)3P0 from (CH30)3PSand (CH3O)2P(0)SCH3from (CH30)2P(S)SCH3,with formation yields of 0.28 f 0.04 and 0.13 f 0.05, respectively. While the majority of the reaction products were not accounted for, these data may account for the observations of a rapid transformation of organophosphorus compounds containing a thiophosphoryl bond to their corresponding analogues containing a phosphoryl bond in ambient air.
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