Thermal Degradation of Selected Fungicides and ... - ACS Publications

7 Thermal Degradation of Selected Fungicides and Insecticides MAURICE V. KENNEDY Department of Biochemistry, Mississippi State University, Mississippi State, MS 39762 MILES E . H O L L O M A N Propulsion Directorate, U.S. Army Missile Command, Redstone Arsenal, A L 35809

Downloaded by UNIV OF ARIZONA on March 8, 2017 | http://pubs.acs.org Publication Date: June 30, 1978 | doi: 10.1021/bk-1978-0073.ch007

FAY Y. HUTTO Mississippi State Chemical Laboratory, Mississippi State, MS 39762

One major problem facing agricultural leaders of today is the disposal of large quantities of waste pesticides without contamination of the environment. The wide variety of chemicals used as pesticides complicates the disposal problem by making it difficult to develop a single method of disposal which can be universally employed. In the past settling ponds, ground burial, deep-well injection, and incineration have been the principal methods for disposal of chemical wastes (1). The first three procedures may not be suitable for disposal of large amounts of pesticides because they do not guarantee that the pesticides will remain at the disposal site. Pesticides may be transported over and through soil by either runoff or ground water (2). Thus, pesticide disposal by any of these methods might not only prevent future use of the disposal site for agricultural purposes but might also trigger widespread environmental pollution by these chemicals. Incineration, however, has shown promise of being an efficient means of pesticide disposal (3). Since the aim of incineration is complete destruction of the pesticide molecule, a number of factors concerning the thermal degradation of pesticides must be determined in order for this process to be fully evaluated as a possible method of pesticide disposal. The degradation temperature for each compound considered as a possible candidate for incineration must be known. Moreover, combustion of pesticides may produce a number of toxic gases (4,5). Identities of all the potential pollutant gases produced by each pesticide must, therefore, be known in order to facilitate development of a scrubber system capable of minimizing air pollution. A comprehensive investigation of pesticide combustion products must also include products of incomplete combustion which may be formed under non-optimum combustion conditions, i . e . , during an incinerator malfunction. The purpose of the present study was to provide preliminary information concerning the degradation of two fungicides and four insecticides and to identify the pollutant 0-8412-0433-0/78/47-073-081$05.00/0 © 1978 American Chemical Society

Kennedy; Disposal and Decontamination of Pesticides ACS Symposium Series; American Chemical Society: Washington, DC, 1978.

DISPOSAL AND DECONTAMINATION OF PESTICIDES

82

i d e n t i f y the p o l l u t a n t gases produced under optimum and nonoptimum c o n d i t i o n s o f p e s t i c i d e i n c i n e r a t i o n .


Experimental

Section

Fungicides and I n s e c t i c i d e s . The p e s t i c i d e s used i n t h i s i n v e s t i g a t i o n were t h e two f u n g i c i d e s and four i n s e c t i c i d e s s t u d i e d under USDA Cooperative Agreement 12-14-7001-108. A n a l y t i c a l standards and commercial formulations were s u p p l i e d by the r e s p e c t i v e manufacturers o f t h e f o r m u l a t i o n s . The chemical names o f p e s t i c i d e s and the formulations used i n t h i s i n v e s t i g a t i o n a r e as f o l l o w s : Captan, N - ( t r i c h l o r o m e t h y l t h i o ) - 4 cyclohexene-1, 2dicarboximide; O r t h o c i d e ^ S O wettable powder c o n t a i n i n g 50% active ingredient. Maneb, manganeous e t h y l e n e b i s d i t h i o carbamate; Manzate wettable powder c o n t a i n i n g 80% a c t i v e i n g r e d i e n t . Methyl P a r a t h i o n , 0_, 0- dime thy l-O^-pj-nitrophenyl phosphorothioate; l i q u i d Methyl P a r a t h i o n 4-E c o n t a i n i n g 44% a c t i v e i n g r e d i e n t . Mirex, dodecachlorooctahydro-1,3,4-metheno-lH-cyclobutal [cd]pentalene; Mirex 4 c o n t a i n i n g 0.3% a c t i v e i n g r e d i e n t ( o i l suspension on corn cob g r a n u l e s ) . Temik, 2-methyl-2-(methylthio) propionaldehyde-0(methylcarbamoy 1 ) oxime ; Temik^lOG c o n t a i n i n g 10% a c t i v e i n g r e d i e n t (10% t e m i k impregnated on corn cob g r a n u l e s ) . Toxaphene, a mixture o f c h l o r i n a t e d camphenes o f u n c e r t a i n i d e n t i t y (combined c h l o r i n e content = 67-69%); l i q u i d f o r m u l a t i o n c o n t a i n i n g 90% t e c h n i c a l toxaphene and 10% xylene. R

R

Fungicide and I n s e c t i c i d e A n a l y s i s . The c o n c e n t r a t i o n o f a c t i v e i n g r e d i e n t i n each p e s t i c i d e f o r m u l a t i o n was e s t a b l i s h e d by t e n determinations. The mean values obtained a r e given i n Table I . G a s - l i q u i d chromatographic procedures were used f o r captan, methyl p a r a t h i o n , mirex, and toxaphene. Maneb was analyzed by t h e carbon d i s u l f i d e e v o l u t i o n method (6) and temik by an i n f r a r e d specrtrophotometric method (_7) . The captan, methyl p a r a t h i o n , and toxaphene f o r m u l a t i o n s d i d not r e q u i r e cleanup. Captan was d i s s o l v e d i n acetone and methyl p a r a t h i o n and toxaphene i n hexane. A l i q u o t s o f these s o l u t i o n s were d i l u t e d w i t h hexane t o t h e a p p r o p r i a t e concentration for analysis. The mirex f o r m u l a t i o n r e q u i r e d t h e f o l l o w i n g cleanup procedure (8). Samples were d i s s o l v e d i n hexane and c e n t r i f u g e d t o remove t h e i n s o l u b l e m a t e r i a l s . The supernatant l i q u i d was t r a n s f e r r e d t o a beaker c o n t a i n i n g d e a c t i v a t e d f l o r i s i l and mixed w i t h t h e f l o r i s i l . The d r i e d mixture was e x t r a c t e d f i v e times w i t h petroleum ether and the combined e x t r a c t s were evaporated t o dryness. The r e s i d u e was d i s s o l v e d i n hexane f o r a n a l y s i s .


Kennedy; Disposal and Decontamination of Pesticides ACS Symposium Series; American Chemical Society: Washington, DC, 1978. L

65-90

Toxaphene

90.2

10.8

WP « Wettable powder, L « liquid, CC » corn ccb support.

CC

98-100

Temik

CC

0.3

200

44.2

Decomposes at 485

37-38 L

200

80.0

WP

400

200

300

200

46.5

WP

Decomposes before melting

172-173

(°C)

Temperature of A. I. Elimination Open Crucible

Observed Active Ingredient (%)

Tvpe Of j Fo:rmulation

Mirex

Methyl Parathion

Maneb

Captan

Pesticide

Melting Point

94.2

15.8

47.9

64.7

37.0

29.2

m

Weight Loss

99.9

99.3

99.3

97.5

72.2

58.2

(-/)

Weight Loss at 1000°C

TEMPERATURES REQUIRED FOR PESTICIDE DEGRADATION IN OPEN AND CLOSED SYSTEMS


250

175

525

200

200

275

(°C)*

Initial Degradation Temperature Sealed Aroule


84


A Barber-Colman 5000 s e r i e s gas chromatograph equipped w i t h a t r i t i u m e l e c t r o n capture d e t e c t o r was employed f o r these analyses. The g l a s s column, 6 f t . χ 4 mm i . d . , was packed w i t h 1.5% OV-17, 1.95% QF-1 on 100/120 mesh Chromosorb W ( 9 ) . I n j e c t o r , column, and d e t e c t o r temperatures were 210°C, 200°C, and 210OC, r e s p e c t i v e l y . The c a r r i e r gas was n i t r o g e n a t a f l o w r a t e o f 100 ml/min. Q u a n t i t a t i o n o f the captan, methyl p a r a t h i o n , and mirex chromatograms was accomplished by t h e peak h e i g h t method. The toxaphene chromatograms were q u a n t i t a t e d by determining the t o t a l area under the toxaphene peaks u s i n g a Westronics Model 222 d i s c i n t e g r a t o r . T h i s method was determined t o be 99.5% reproducible. M u f f l e Furnace Treatments. The temperatures a t which the a c t i v e i n g r e d i e n t was completely e l i m i n a t e d from each f o r m u l a t i o n was determined i n a m u f f l e furnace i n the f o l l o w i n g manner. Samples o f the p e s t i c i d e s were weighed i n Coors No. 0 p o r c e l a i n c r u c i b l e s and heated a t 100°C increments from 100°C t o 1000°C. Each d e t e r m i n a t i o n was conducted i n t r i p l i c a t e i n the temperature range o f 100°C t o 500°C and i n d u p l i c a t e a t the h i g h e r tempera t u r e s . The optimum time o f h e a t i n g f o r each p e s t i c i d e was e s t a b l i s h e d by v a r y i n g the time o f h e a t i n g a t 100°C, 500°C, and 800OC. A h e a t i n g time o f 45 min was found t o be s u f f i c i e n t t o reach a p o i n t o f no f u r t h e r r e a c t i o n . The c o o l e d samples were then analyzed f o r weight l o s s and content o f a c t i v e i n g r e d i e n t by the methods d e s c r i b e d p r e v i o u s l y . The c r i t e r i o n used f o r e l i m i n a t i o n o f t h e a c t i v e i n g r e d i e n t was no d e t e c t a b l e amount of p e s t i c i d e a t the yg/ml l e v e l o f r e s i d u e c o n c e n t r a t i o n f o r the p e s t i c i d e s analyzed by gas chromatography and the mg/ml l e v e l f o r thos analyzed by wet methods. An u n t r e a t e d sample o f the commercial f o r m u l a t i o n was analyzed as a q u a l i t y c o n t r o l sample along w i t h each group o f heated samples. Sealed Ampoule Determinations. The temperatures a t which degradation o f the a n a l y t i c a l grade p e s t i c i d e s i n i t i a t e d was determined as f o l l o w s . Samples were s e a l e d i n 10 ml ampoules and heated i n a m u f f l e furnace i n increments o f 25°C beginning a t t h e i r m e l t i n g p o i n t s and c o n t i n u i n g t o some temperature a t which degradation was confirmed. Sample s i z e s were approximately 20 mg and h e a t i n g time was 15 min a t each temperature. The c r i t e r i a used t o e s t a b l i s h the temperature a t which thermal degradation was i n i t i a t e d were the temperature a t which the i n f r a r e d spectrum d e v i a t e d from t h a t o f the u n t r e a t e d p e s t i c i d e due t o t h e disappearance o f one o r more major a b s o r p t i o n s and/or a change i n p h y s i c a l appearance o f the p e s t i c i d e . A l l i n f r a r e d s p e c t r a were o b t a i n e d u s i n g 13 mm KBr p e l l e t s o r Œ>2 o r C C I 4 s o l u t i o n s . The instrument was a Perkin-Elmer 337 g r a t i n g spectrophotometer. S p e c t r a o f the u n t r e a t e d p e s t i c i d e s were compared t o those i n the S a d t i e r Index when p o s s i b l e (10).



7.

KENNEDY ET AL.

Fungicides

and

Insecticides

85

P o l l u t a n t Gas A n a l y s i s . Two i n v e s t i g a t i o n s were conducted t o determine the v o l a t i l e products o f p r e s t i c i d e combustion. The f i r s t study was the experimental d e t e r m i n a t i o n o f the gaseous products formed d u r i n g h e a t i n g i n the temperature range o f 400 525°C. A n a l y t i c a l grade p e s t i c i d e s (50-100 mg) were s e a l e d i n 10 ml ampoules and heated i n a m u f f l e furnace f o r 15 minutes. I d e n t i f i c a t i o n o f the gaseous products was accomplished by a combination o f mass spectrometry and gas chromatography. The mass spectrometer was a V a r i a n Anaspect ΕΜ-600 equipped w i t h an EM 6270 gas sampling adapter. Gaseous samples were introduced w i t h the adapter a t an i n l e t temperature o f 180°C. S p e c t r a were obtained a t i o n i z i n g v o l t a g e s of 70 eV and approximately 25 eV and were i n t e r p r e t e d by u s i n g a computer program. The program l i s t e d a l l p o s s i b l e combinations o f the elements contained i n a p e s t i c i d e which would g i v e each of the masses p r e s e n t i n the spectrum o f i t s gaseous p r o d u c t s . The most probable gas (or gases) were s e l e c t e d f o r p o s s i b l e c o n f i r m a t i o n by gas chroma tography u s i n g a Barber-Colman 5000 s e r i e s chromatograph equipped w i t h a thermal c o n d u c t i v i t y d e t e c t o r . A l l columns were 6 f t . by 4 mm i . d . g l a s s columns. The f o l l o w i n g packings and c o n d i t i o n s were used: (1) 80/100 mesh Deactigel? i n j e c t o r , column, and d e t e c t o r temperatures o f 120°C, 120°C, and 125°C, r e s p e c t i v e l y ? c a r r i e r gas-helium a t a f l o w r a t e o f 50 ml/min (11); (2) 10% A r o c h l o r 1232 on 40/60 mesh Chromosorb Τ; i n j e c t o r , column, and d e t e c t o r temperatures o f 30°C, 30°C, and 100°C, r e s p e c t i v e l y ? c a r r i e r gas-helium a t a f l o w r a t e o f 15 ml/min (12). The second study was the t h e o r e t i c a l p r e d i c t i o n o f the combustion products which would r e s u l t s from i n c i n e r a t i o n o f the p e s t i c i d e s under c o n d i t i o n s o f complete combustion. Complete combustion was determined by the a d d i t i o n o f s u c c e s s i v e amounts o f a i r u n t i l a p e s t i c i d e t o a i r r a t i o was o b t a i n e d a t which a s m a l l excess o f d i a t o m i c oxygen was p r e s e n t . Temperatures s t u d i e d were 1727°C and 27°C. The NASA/LEWIS Chemical E q u i l i b r u m Composition Computer Program (13) was used t o p r e d i c t the products which would be thermodynamically s t a b l e under these c o n d i t i o n s . T h i s program, which contained the thermochemical p r o p e r t i e s o f most o f the combustion products t o be expected from i n c i n e r a t i o n o f t y p i c a l halogenated hydrocarbons, was amended t o i n c l u d e the thermochemical p r o p e r t i e s o f o t h e r compounds i n d i c a t e d t o be present by the experimental d a t a . The thermodynamic d a t a were obtained from the l i t e r a t u r e (14-17). M u f f l e Furnace R e s u l t s . The temperatures a t which the a c t i v e i n g r e d i e n t was e l i m i n a t e d from each f o r m u l a t i o n and the accompanying weight l o s s e s a t these temperatures are g i v e n i n Table I . There are s e v e r a l p o s s i b l e pathways o f p e s t i c i d e l o s s d u r i n g these treatments. Three of the p o s s i b i l i t i e s are decom p o s i t i o n w i t h o u t v o l a t i l i z a t i o n , decomposition f o l l o w e d by v o l a t i l i z a t i o n o f the p r o d u c t s , and v o l a t i l i z a t i o n w i t h o u t decomposition. The weight l o s s e s i n d i c a t e t h a t i n each i n s t a n c e


86



c o n s i d e r a b l e q u a n t i t i e s o f gases were evolved a t these temperat u r e s . The r e s i d u e s remaining a f t e r h e a t i n g captan, methyl p a r a t h i o n and maneb a t 1000°C were f e l t t o be the r e s u l t o f the presence o f i n o r g a n i c s a l t s i n the c a r r i e r o r t o formation o f such s a l t s d u r i n g h e a t i n g . The low temperature a t which mirex could no longer be d e t e c t e d (Table I) l e d t o the s u s p i c i o n t h a t v o l a t i l i z a t i o n p r i o r t o d e g r a d a t i o n might be o c c u r r i n g i n some i n s t a n c e s . T h i s i n s e c t i c i d e has p r e v i o u s l y been r e p o r t e d t o be t h e r m a l l y s t a b l e w i t h p y r o l y s i s o c c u r r i n g o n l y about 500°C (18,19). Sealed Ampoule R e s u l t s . Since t h e r e was no way t o prevent the escape o f a v o l a t i l e product from the c r u c i b l e s , the minimum temperatures a t which d e g r a d a t i o n o f the p e s t i c i d e s was i n i t i a t e d was determined i n sealed ampoules i n order t o prevent the p o s s i b i l i t y o f v o l a t i l i z a t i o n p r i o r t o d e g r a d a t i o n . Table I a l s o c o n t a i n s the r e s u l t s o f t h i s study. Comparison o f the open c r u c i b l e and sealed ampoule r e s u l t s i n d i c a t e d the i n i t i a l degradation temperatures o f maneb, methyl p a r a t h i o n , and temik were s i m i l a r t o the temperatures a t which the compounds were e l i m i n a t e d from the r e s i d u e s i n the c r u c i b l e s . No v a p o r i z a t i o n of maneb was observed i n the ampoule a t temperatures below the i n i t i a l d e g r a d a t i o n p o i n t . However, methyl p a r a t h i o n and temik were s i m i l a r t o the temperatures a t which the compounds were e l i m i n a t e d from the r e s i d u e s i n the c r u c i b l e s . No v a p o r i z a t i o n of maneb was observed i n the ampoule a t temperatures below the i n i t i a l d e g r a d a t i o n p o i n t . However, methyl p a r a t h i o n and temik v a p o r i z e d a t 125°C and 150°C r e s p e c t i v e l y , i n i t i a l degradation temperatures o f captan and mirex were c o n s i d e r a b l y h i g h e r than the temperatures a t which these compounds disappeared from the c r u c i b l e s (Table I ) . These r e s u l t s support the theory t h a t these two compounds were v o l a t i l i z e d from the c r u c i b l e p r i o r t o being degraded. Toxaphene appeared t o be degraded i n the ampoule a t a temperature c o n s i d e r a b l y lower than the temperature at which i t was no longer d e t e c t e d i n the c r u c i b l e . However, chromatograms o f toxaphene heated t o 300°C i n the open c r u c i b l e showed an a l t e r i n g o f composition as compared t o the u n t r e a t e d p e s t i c i d e , and no toxaphene was d e t e c t e d i n the r e s i d u e produced at 400°C. V o l a t i l i z a t i o n o f toxaphene i n the ampoule was noted at temperatures above 125°C. R e s u l t s o f these two s t u d i e s seem t o i n d i c a t e t h a t the i n i t i a l d e g r a d a t i o n temperatures determined i n the sealed ampoules are more a c c u r a t e than those determined i n the c r u c i b l e s because i t was i m p o s s i b l e f o r the p e s t i c i d e t o escape. P o l l u t a n t Gas A n a l y s i s . The c o n d i t i o n s used i n the l a b o r a t o r y study were intended t o s i m u l a t e an i n c i n e r a t o r m a l f u n c t i o n d u r i n g which incomplete combustion would occur as the r e s u l t o f the low temperature (400 - 525°C) and an i n s u f f i c i e n t oxygen



7.

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87

Insecticides

supply. The h e a t i n g temperatures f o r a l l p e s t i c i d e s except mirex, were c o n s i d e r a b l y h i g h e r than the minimum degradation temperatures determined i n the sealed ampules. D i s c u s s i o n o f the gaseous combustion products i s l i m i t e d t o p o l l u t a n t gases. However, a number o f o t h e r gases were p r e s e n t i n a l l o f the m i x t u r e s . For i n s t a n c e , the mass s p e c t r a i n d i c a t e d the presence o f atmospheric n i t r o g e n , oxygen and argon as w e l l as the water vapor and carbon d i o x i d e formed as a r e s u l t o f combustion. The presence o f oxygen may have r e s u l t e d from a l e a k i n the gas sampling system. No s p e c i a l attempts were made t o c o n f i r m any o f these gases s i n c e they a r e not environmental hazards. The presence o f CO was a l s o n o t confirmed s i n c e i t i s a known product o f incomplete combustion. I n c i n e r a t i o n o f maneb a t 400°C produced a carbonaceous m a t e r i a l . The mass spectrum c o n s i s t e d o f 10 peaks, assignments o f which a r e g i v e n i n Table I I . From t h i s t a b l e i t i s obvious t h a t the p o l l u t a n t gases CH4, NH3, CO, and N20 cannot be p o s i t i v e l y i d e n t i f i e d from the mass s p e c t r a because t h e i r masses a r e i d e n t i c a l t o t h e masses o f o t h e r species (O, OH, N 2 , and C0 # r e s p e c t i v e l y ) which were p r e s e n t i n most o f the s p e c t r a . P o l l u t a n t s t e n t a t i v e l y i d e n t i f i e d from the spectrum o f the maneb gaseous product m i x t u r e were Ν 0 , COS, and C S 2 . The s u l f u r c o n t a i n i n g gases, CO2 and 20 were confirmed on the D e a c t i g e l column. The r e s i d u e remaining a f t e r h e a t i n g methyl p a r a t h i o n a t 400°C was a l s o carbonaceous. The mass spectrum o f the gaseous products was q u i t e complex, c o n t a i n i n g 29 peaks. Assignments f o r these peaks a r e presented i n Table I I . P o l l u t a n t s t e n t a t i v e l y i d e n t i f i e d were HCN, N 0 , COS, SO2, and C S 2 . The presence o f C 0 , COS, and C S was confirmed on the D e a c t i g e l column and a peak w i t h a r e t e n t i o n i d e n t i c a l t o H2S was a l s o p r e s e n t i n the chromatogram. S u l f u r d i o x i d e , however, was not confirmed and the peak a t a mass o f 64 was b e l i e v e d t o have r e s u l t e d from f u r t h e r fragmentation o f the PSO2+ fragment (mass = 9 5 ) . I n c i n e r a t i o n o f temik a t 400°C produced a carbonaceous r e s i d u e . The mass spectrum o f the gaseous products contained 20 peaks. Assignments o f these peaks a r e a l s o l i s t e d i n Table I I . P o l l u t a n t s t e n t a t i v e l y i d e n t i f i e d from the spectrum were HCN and COS. The chromatogram r e s u l t i n g from passage o f the gas m i x t u r e through the D e a c t i g e l column confirmed the presence o f CO2 and a l s o c o n t a i n e d two peaks w i t h r e t e n t i o n times i d e n t i c a l t o those of H S and C S . The c o n c e n t r a t i o n o f COS i n the gas mixture was e v i d e n t l y below t h e l i m i t o f d e t e c t i o n o f the chromatographic system. The r e s i d u e remaining a f t e r h e a t i n g captan a t 400°C was a l s o carbonaceous. The mass spectrum o f the gaseous products contained 14 peaks, assignments o f which a r e g i v e n i n Table I I I . P o l l u t a n t gases t e n t a t i v e l y i d e n t i f i e d were HCL, COS, SO2, C S 2 , and C H C I 3 . C o n f i r m a t i o n o f t h e s u l f u r - c o n t a i n i n g gases and CO2 was accomplished w i t h the D e a c t i g e l column. The chromatogram 2

2

2

2

2

2

2


88


TABLE II

MASS SPECTRAL DATA FOR SULFUR-CONTAINING PESTICIDES HEATED AT 400 C


14

Assignment

Confirmed by GC

*

+

Confirmed by GC

Assignment Confirmed by GC

0\ +

0H , H

2

+

NH , C H

16

18

Assignment

Ν

15

17

Temik

Methyl Parathion

Maneb AMU

NH

+

+ +' + Ο , ΚΗ , C H

N H \ CH,

2

2

+

0H ,

3

3

NH

OH *, Η\\*

+ 3

Η/

H /

0 +

4

4

+

HCN

27 28

K

0

HCN

+

N , CO +

, CO

+

+

Ν , CO

14,15

29

14.15.. + 2

+ W

+

2

2

h

2

32

Unidentified

35 40

Ar

Ar

Ar

+

C « , C H N

41

3

42

C

3 6 H

C H

43 44

5

3

C0«

Yes

C0„

N0

Yes

N 0"

2

Yes

2

+

+ ?

Yes

CO* N 0'

2

2

+

45

C H P , C0 H

46

C H P , NO

2

47

CH P , PO

+

+

48

CH Ρ , SO

49

Unidentified

2

2

+

3

+

+

3

C0 H

+

2

+

A

5


KENNEDY ET AL.

Fungicides and Insecticides

TABLE I I (Cont'd)


Maneb AMU

Assignment

57

—

58

—

59

—

60

COS *

Methvl Parathion Confirmed by GC

Assignment

C H P C

2

2

H

P +

2 3

Confirmed by GC

Temik Assignment Confirmed by GC

+

+

C0 N , C H S 2

2

+

2

4

CJl.P * 4

4

Yes

4

COS*

COS*

v

xes 61

—

C

2 6 »

H

P+

Cli

62

—

C

2 7 »

H

P+

C H

63

—

P0 , FS

64

—

S0

2

76

CS

CS

2

+

+ 2

Yes

+

+

Yes

+

P0 ,PS0

94

-

-

*

? 0 +

+

—

—

3

P0+

2

79

95

'2

3

PS0

+

+

CH S0 , CH S 3

H

2

S0

3

+

C

H

S

+ 2

C 6 2 » 2 6 2* 2

+ 2

Means that no peak occurred at the specified mass number.


90


TABLE I I I

MASS SPECTRAL DATA FOR CAPTAN' AND TOXAPHENE HEATED AT 400°C AND MIREX HEATED AT 525°C


Captan AMU

Assignment

4

+

0,

—

0H H 0

+

CH

O *, C H

4

N ,

C0

2

+ A

4

OH*

+

+

H

2

0 +

C

2 3

H

+

+

4

N » CO*

N , CO*

+

Confirmed by GC

2

4

+

—

+

Assignment

N \ CH

2

H /

2

27 28

Toxaphene

Confirmed by GC

+

N*, C H

17 18

Assignment

4c

14 16

Mirex Confirmed by GC

4

2

2

32 35 36

—

Cl

Cl

+

4

HCl *

37

—

38

H C1

40

Ar

44

C0

45

—

HC1 3 7

37

Yes

+

C1

+ 4

H^Cl *

+

Ar +

Yes

2

C 0

+

C1

+

37

H C1

Ar

+

+

Yes

+

—

C0 H

+

2

4

CCI *

47 4

48

CHC1 *

49

—

60

COS*

61

—

— 37

c ci+ 4

Yes

— —

C H C1

+

C H C1

+

2

62

63

Yes

+

2

HC1 3 7

+

+

2

—

4

coci *

2

3

coci*;

C H CI*-, 2

4


7.

KENNEDY ET AL.


91

TABLE I I I (Cont'd)

Captan


AMU

Assignment

SO.

64

Confir mod by GC

Mirex Assignment Confirmed by GC

Assignment Confirmed by GC

Yes 37

C0 C1

65 70

C 1

3 5

72 76

Toxaphene

cs cs V

+

Yes

2 3 7

C1 C1

+

Yes

ci

2

35 37 c l

c l +

Yes

2

3

78

Yes

CCI,

82 83

CHCl, 3 7

cci ci

84

+

37 + CHC1 CI

85

3 7

+

c ci

86

2

C H C1

96

2

2

2

+

coci

98

C0C1 , C H C l 2

100

37 + C0C1 CI

117

cci

4

37

+ 2

t

C H C1 C1 2

cci cci ci" 3

3

3 7

3 7

119

cci

121

cci ci

ci

123

c ci

152

cci

2 3 7

3 7

+

f

2

+ 2

+ 3

Yes

+ 4 3 7

h

154

cci ci*

156

CC1 C1+

3

37

—

2

2

Yes Yes

means that no peak occurred at the specified mass number.


2

+

DISPOSAL AND DECONTAMINATION OF PESTIODES

92

a l s o contained a peak w i t h a r e t e n t i o n time i d e n t i c a l t o t h a t of H S. Mirex was more r e s i s t a n t t o thermal degradation than any o f the o t h e r p e s t i c i d e s . Even a f t e r h e a t i n g a t 525°C the r e s i d u e was n o t carbonaceous b u t c o n s i s t e d o f l o n g , o f f - w h i t e c r y s t a l s and l i q u i d d r o p l e t s . The mass spectrum o f the gaseous products c o n s i s t e d o f 30 fragments, assignments o f which a r e presented i n Table I I I . The t o x i c gases t e n t a t i v e l y i d e n t i f i e d were i d e n t i c a l t o those r e s u l t i n g from i n c i n e r a t i o n o f mirex a t 550°C (20). C o n f i r m a t i o n o f HCl, C l f and CCI4 was accomplished w i t h t h e A r o c h l o r 1232 column and carbon d i o x i d e was confirmed on t h e D e a c t i g e l column. The r e s i d u e remaining a f t e r h e a t i n g toxaphene a t 400°C c o n s i s t e d o f a carbonaceous s o l i d and a b l a c k l i q u i d . The mass spectrum o f t h e gaseous products c o n t a i n e d o f 23 fragments, assignments o f which a r e g i v e n i n Table I I I . The primary p o l l u t a n t was HCl. Other p o s s i b i l i t i e s t e n t a t i v e l y i d e n t i f i e d from the spectrum were C H C1, C H C 1 , C l , C H C 1 , C0C1 , C H C 1 , and C C I 4 . V i n y l c h l o r i d e was confirmed on the D e a c t i g e l column but no C2H4CI was d e t e c t e d . The presence o f C C I 4 was confirmed on the A r o c h l o r 1232 column. The complete combustion products p r e d i c t e d by the thermodynamic c a l c u l a t i o n s a r e g i v e n i n Tables IV and V. The number o f moles o f a i r r e q u i r e d f o r complete combustion o f one mole o f p e s t i c i d e was 50 f o r mirex, 55 f o r captan, temik, and toxaphene, and 60 f o r maneb and methyl p a r a t h i o n . The h i g h e r temperature represents t h e o p e r a t i n g range o f commercial i n c i n e r a t o r s w h i l e the lower temperature s i m u l a t e s the c o o l e d exhaust. The e q u i l i brium product d i s t r i b u t i o n s a r e presented as the mole f r a c t i o n of each product formed from t h e t h e o r e t i c a l i n c i n e r a t i o n o f each p e s t i c i d e i n t h e presence o f the s p e c i f i e d moles o f a i r . The major products p r e d i c t e d under these c o n d i t i o n s were r a t h e r simple except f o r those r e s u l t i n g from the presence o f manganese i n maneb and phosphorus i n methyl p a r a t h i o n . The carbon component was o x i d i z e d p r i m a r i l y t o C 0 w i t h s m a l l q u a n t i t i e s o f CO a l s o b e i n g formed. P e s t i c i d e n i t r o g e n was converted mainly t o N and s m a l l amounts o f NO. Most o f the hydrogen formed H 0 o r HCl. S u l f u r was o x i d i z e d p r i m a r i l y t o S 0 and SO3 except f o r maneb. C h l o r i n e was converted mainly t o HCl o r C l . Maneb was t h e o n l y p e s t i c i d e which y i e l d e d s o l i d products a t h i g h temperatures. A t 1727°C t h e manganese was o x i d i z e d t o MnO (Table I V ) . T h i s compound then r e a c t e d w i t h t h e s u l f u r oxides as the gases were c o o l e d t o form MnS04. The phosphorus i n methyl p a r a t h i o n was converted mainly t o P 0 and P4O5 a t 17270C and P 4 0 a t 27°C (Table I V ) . The r e s u l t s o f t h i s study were somewhat s i m p l i f i e d by t h e use o f a thermodynamic model t o p r e d i c t t h e products o f i n c i n e r a t i o n . Three o f t h e systems a f f e c t e d by t h e n e g l e c t o f k i n e t i c s were t h e CO, NO, and SO2-SO3 systems. 2


2

2

3

2

5

2

2

2

2

2

2

2

2

2

2

2

2

1 0


4

2

7. KENNEDY ET AL.

93


I n r e c e n t years the k i n e t i c s o f CO and NO formation and d e s t r u c t i o n have been w i d e l y i n v e s t i g a t e d (21,22). Results o f these i n v e s t i g a t i o n s i n d i c a t e t h a t a c t u a l CO concentrations in automobile exhaust are s i m i l a r t o the e q u i l i b r i u m values a t the combustion temperatures r a t h e r than the e q u i l i b r i u m v a l u e s a t the exhaust temperatures. N i t r i c oxide formation has been found t o occur by two routes. The f i r s t path i s o x i d a t i o n o f atmospheric n i t r o g e n a t temperatures above 1760°C by the f o l l o w i n g reactions.


N

2

+ 0.

Ν· + 0 Ν

2

+ OH

+ NO + N+ NO + O+ NO + Η·

The other route i s the o x i d a t i o n o f p e s t i c i d e n i t r o g e n . Kinetics of t h i s r e a c t i o n are o f the same order as the combustion process. K i n e t i c s o f CO and NO d e s t r u c t i o n , however, are l i m i t e d d u r i n g expansion. As a r e s u l t , considerable q u a n t i t i e s o f these gases w i l l probably be present i n i n c i n e r a t o r exhaust. Although the c a l c u l a t i o n s i n d i c a t e d t h a t the s u l f u r w i l l be converted t o S 0 and SO3 (Tables IV and V ) , s t u d i e s o f exhaust gases from s u l f u r - c o n t a i n i n g f u e l s have i n d i c a t e d t h a t o n l y 1-3% of the s u l f u r w i l l be o x i d i z e d t o SO3 (23). This f i n d i n g i n d i cates t h a t considerable S 0 w i l l probably be present i n i n c i n e r a t o r exhaust during combustion o f s u l f u r - c o n t a i n i n g p e s t i c i d e s even though none was p r e d i c t e d by the thermodynamic model. Moreover, the SO3 formed w i l l r e a c t w i t h H 0 t o y i e l d H S04 2

2

2

2

(23)· Conclusions Heating o f f u n g i c i d e s and i n s e c t i c i d e s under both optimum and non-optimum c o n d i t i o n s o f combustion produced a number o f p o t e n t i a l a i r p o l l u t a n t s . On a p r a c t i c a l b a s i s a l l o f these gases must be scrubbed from the i n c i n e r a t o r e f f l u e n t p r i o r t o i t s d i s c h a r g e i n t o the atmosphere. Therefore, a scrubber system capable o f absorbing the p o l l u t a n t gases must be developed before i n c i n e r a t i o n can be u t i l i z e d as a method o f d i s p o s a l f o r these p e s t i c i d e s .

Abstract Degradation of six selected fingicides and insecticides was investigated in both open and closed systems. There was evidence that vaporization prior to degradtion could occur in open crucibles. I n i t i a l degradation temperatures determined in sealed ampoules were 275°C for captan, 200°C for maneb and methyl parathion, 525°C for mirex, 175°C for temik, and 250°C



0.00

5

1. 16 X i o "

2. 81 X ί ο "

6. 83 X ί ο "

ii

UNO

110.,

6.70 X ί ο "

5.89 X ί ο "

9.50 X ί ο "

4

4

2

1..30 X ! θ "

8..98 X H)"

3.90 X Ι Ο "

0

Oit

9

0.00

5.47 X ί ο "

7.98 X ί ο "

7

7.,57 X ί ο "

1,,71 X ί ο "

ΐ,.,0

N

3

2 8

2 0

1 2

2 8

2

0.00 7.65 X ί ο " 2.84 X ί ο "

4

3

2

1.29 X i o " 1.14 X ί ο " 3.80 X 10~

1.05 X i o -

0.00 5.53 X ί ο " 8.71 X ί ο "

5

3

7

6.A3 X 10~ 1.13 X Ι Ο "

2

1.62 X i o -

2 8

3

7.32 X ί ο " 4.9A X ί ο "

1

2 0

7.25 X 10" 2 1

7.40 X ί ο " 8.85 X ί ο "

7.21 X ί ο " 7

8.91 X ί ο " 9.63 X ί ο " 1

1.60 X i o "

1 2

6.7 A X ί ο " 7 1 1

1

1 7

0.00 3

2.16 X ί ο "

0.00

1 6

1

2.26 X

2.87 X ί ο "

1

9.86 X ί ο "

Î«>

1

2

r

1.22 X i o -

3

3.31 X 10"

7.34 X Ι Ο "

0.00 1 0

2 4

1 0

1.09 X ί ο " 1 0

2

2

2 9

2.1A X i o ~

7.65 X i o -

0.00 0.00

3.61 X i o ~

0.00

J 0

1 7

1 0

2.77 X 10"

8

3.16 X ί ο "

1

1.15 x Ι Ο "

2 4

2

2.00 X ί ο "

3.28 X ί ο "

8.51 X ί ο "

0.00

2

1.40 X i o -

2.79 X ί ο "

6

4.53 x 1 0 '

0.00

2..40 X io- '

KO

3

1.. 12 X H ) "

m

3. A3 X l u "

7.63 X ί ο "

0.00

1 0

0.00

0.00

1 0

1, 51 X l u "

~

7. 75 X ί ο "

0

M

1

1.17 X

1 0

1. 77 X i n "

O.,

l!

7.56 X ÎO"

3.34 X 10 -

2

A

2.60 X 10"

4

1.12 X ί ο "

8 4

7

2.16 x ί ο "

0.00

8.79 X ί ο " 0.00

8

1.42 X i o ~ 2.26 κ i o "

0.00

8

0.00

3

1

7

x ίο"

1.42 X ί ο "

2

2

0.00

5

3.48 X i o -

A. 71 X ί ο "

U

1.17 0.00

1

1.15 X Ι Ο "

1

2.61 X 1 ( Γ

0.00

5

27 8.53 X Ι Ο " 0.00

1.25 x ï o -

2 8

3

3

8.45 x ΙΟ""

Tonik

1.18 x Ι Ο "

3

1727

0.00

8.72 x ί ο "

1.71 X i o "

1.13 X ί ο - ;

4

1.66 X ί ο "

2

2 9

2

3

8.52 x ί ο " 8.15 x i o "

27

Mothvl Parathion

2 ίΙ,,β

0.00

3

1727

0. 00

ll

C ( L )

9.51 X ί ο "

8

7

1. 33 X i c f

CO,

2

0.00

2

5

6. 33 x ί ο "

CC

0.00

4

9.30 X ί ο "

3

27

8. 85 x l u "

Maneb

A. 16 X i o "

1727

Ar

Product

Combustion and Exhaust Temperatures ( C)

COMBUSTION PRODUCTS* OF SULFUR-CCNTAINING PESTICIDES IN AIR

TABLE IV


o

1

3


0.00

COO

V io

4°i0

P

0.00

0.00

* n.ole fractions L * Iiuuid S « :;eiid.

l

( s )

0.00

Υ\>

0.00

0.00

!

0.00

0.00

i'O

Γ

0.00

0.00

m

0.00

1.67

0.00

0.00

ρ

2

1 0

X

X

ίο""

10~

2

2

5.00

X

3.01 6.00

X

X

1.41 0.00

X

X

X

9.38

1.93

0.00

0.00

0.00

1.68

X

5

10~

io~

ΙΟ"

10~

1.52

2.44

2

1 3

X

1.16

10~

0.00

X

2.85

5

X

3.80 X

io~

3 2

5.06

X

io"

1727

0.00

0.00

X

X

0.00

X

27

9

KnSO, (S)

1.40

X

X

6.33

7.13

X

4.73

3.53

1 0

8

10~

1θ"

io~

1.59

J

?

X

X

1.14

1.59

X

3.98

Maneb

ΠηΟ0

SU

t*

° 3j

1727

0.00

0.00 0.00

2

ICf 4

-8 10 ° 2.71

3.92

0.00

6

ίο" icf

0.00

8

ίο"

0.00

0.00

0.00

1.56

5

ίο"

4.37

2

ίο"

0.00 0.00

10

1.84

5

-

10

l

Thermal Degradation of Selected Fungicides and ... - ACS Publications

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