Research Article Photocatalytic Degradation of Trifluralin ... · e toxicity data indicates that clodinafop-propargyl has low acute oral, dermal, and inhalation toxicity. It has been

Research ArticlePhotocatalytic Degradation of Trifluralin Clodinafop-Propargyland 12-Dichloro-4-Nitrobenzene As Determined by GasChromatography Coupled with Mass Spectrometry

Niyaz A Mir1 A Khan1 M Muneer1 and S Vijayalakhsmi2

1 Department of Chemistry Aligarh Muslim University Aligarh Uttar Pradesh 202002 India2 SAIF CRNTS IIT Bombay Powai Mumbai 400076 India

Correspondence should be addressed to M Muneer readermuneergmailcom

Received 30 May 2014 Revised 17 July 2014 Accepted 17 July 2014 Published 31 August 2014

Academic Editor Teresa Kowalska

Copyright copy 2014 Niyaz A Mir et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Phototransformation is considered one of the most key factors affecting the fate of pesticides Therefore our study focused onphotocatalytic degradation of three selected pesticide derivatives trifluralin (1) clodinafop-propargyl (2) and 12-dichloro-4-nitrobenzene (3) The degradation was carried out in acetonitrilewater medium in the presence of titanium dioxide (TiO

2)

under continuous purging of atmospheric air The course of degradation was followed by thin-layer chromatography and gaschromatography-mass spectrometry techniques Electron ionization mass spectrometry was used to identify the degradationspecies GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basisof molecular ion mass fragmentation pattern and comparison with NIST library The photocatalytic degradation of pesticidesof different chemical structures manifested distinctly different degradation mechanism The major routes for the degradation ofpesticides were found to be (a) dealkylation dehalogenation and decarboxylation (b) hydroxylation (c) oxidation of side chainif present (d) isomerization and cyclization (e) cleavage of alkoxy bond and (f) reduction of triple bond to double bond and nitrogroup to amino

1 Introduction

The contamination of water bodies due to the presenceof pesticides constitutes a pervasive problem and there-fore advanced methods are in demand for the effectivetreatment of these pesticide polluted ground and surfacewaters Advanced oxidation processes have proven effectivefor the removal of organic pollutants During the last twodecades photocatalytic processes involving semiconductorparticles under UV light illumination have been shown tobe potentially advantageous and useful in the degradationof organic pollutants [1ndash3] The process occurs as a resultof the interaction of a semiconductor photocatalyst and UVradiation that yields highly reactive hydroxyl and superoxideradical anions which are believed to be the main speciesresponsible for the oxidation of organic substrates The mostcommonly used photocatalyst is TiO

2 which is inexpensive

abundant photostable and nontoxic [4] The mechanism of

photocatalysis is well documented in the literature [4 5]Briefly when a semiconductor such as TiO

2absorbs a photon

of energy equal to or greater than its band gap energy anelectron may be promoted from the valence band to theconduction band (eminus) leaving behind an electron vacancyor ldquoholerdquo in the valence band (h+) as shown in (1) Ifcharge separation is maintained the electron and hole maymigrate to the catalyst surface where they participate inredox reactions with sorbed species [6 7] In particular h+may react with surface-bound H

2O to produce the hydroxyl

radical and eminus is picked up by oxygen to generate superoxideradical anion (O

2

minus) as indicated in (2) and (3)

TiO2+ ℎV 997888rarr TiO

2

lowast(eminus + h+) (1)

eminus +O2997888rarr O

2

∙minus (2)

H2O + h+ 997888rarr OH∙ +H+ (3)

Hindawi Publishing CorporationChromatography Research InternationalVolume 2014 Article ID 261683 9 pageshttpdxdoiorg1011552014261683

2 Chromatography Research International

The photocatalyzed degradation of pesticides does notoccur directly to release inorganic species but through theformation of prolonged intermediates or degradation prod-ucts which can themselves be toxic and in some cases morepersistent than the original substrate [8ndash10]

Therefore detection and identification of the degradationproducts during photocatalytic treatment are important tooptimize and increase the overall efficiency of the processHowever the intricacy of the reaction pathways formation ofnumerous by-products and the broad range of concentrationand polarity of intermediated products are some of theproblems faced during analytical determination of degrada-tion products Therefore careful analytical screening usingdiverse techniques is essential to examine the various possibletransformation routes and to understand and propose thereaction pathways [11]

Due to the complexity of the electronradical inducedreactions occurring during the photocatalytic processes itis difficult to suggest a comprehensive reaction pathwayexplaining the formation of all detected intermediates How-ever a comparatively adequate number of fairly abundantdegradation products have been recognized during the pro-cess so that a probable scheme can be suggested consider-ing the common transformation processes of other organiccompounds [11] Gas chromatography coupled with massspectrometry is one of themost frequent analytical tools usedfor the detection of degradation products [12ndash14]

Trifluralin (26-dinitro-NN-dipropyl-4-(trifluorometh-yl) aniline) (1) a dinitroaniline herbicide is one of the mostcommon herbicides used to control many annual grassesand broadleaf weeds for agricultural crops [15] Trifluralin iscurrently registered inmore than 50 countries for use on over80 crops [16] It is currently the 3rd and 4th most commonlyused herbicide on cotton and soybean respectively Due to itshydrophobic nature it strongly sorbs to soil and therefore itstransport to the surface and ground water in the dissolved-phase is very limited Offsite transport mainly takes placeby soil erosion and subsequent deposition into streams andlakes or by volatilization losses following field applications[17ndash20] Trifluralin has been classified as group C possiblehuman carcinogen and possesses relatively high toxicity foraquatic organisms Moreover trifluralin is suspected to be anendocrine disruptor [21]

Clodinafop-propargyl (2-propynyl (R)-2-[4-(5-chloro-3-fluoro-2-pyridinyloxy)phenoxy]propionate) (2) is asystemic postemergence herbicide that effectively controlsisoproturon-resistant little seed canary grass biotypes(Phalaris minor Retz) along with other broad-leaved weedsof wheat (Triticum aestivum) [22ndash26] This herbicide isused in combination with a safener cloquintocet-mexylbut has an antagonistic effect with auxin-type herbicides[27] It interferes with the production of fatty acids neededfor plant growth in susceptible grassy weeds [28] Thisherbicide breaks down rapidly in soil and is mobile in soilThe toxicity data indicates that clodinafop-propargyl haslow acute oral dermal and inhalation toxicity It has beenclassified as ldquolikely to be carcinogenic to humanrdquo causingdevelopmental and fetotoxicity in rats This product hasbeen found to be moderately toxic to aquatic organisms

(human health risk assessment for the use of the new activeingredient clodinafop-propargyl on wheat United StatesEnvironmental Protection Agency Office of PreventionPesticides and Toxic Substances Washington DC)

Chloronitrobenzenes are important chemical intermedi-ates in the manufacture of dyes and agricultural pharmaceu-tical and industrial agents [29ndash33] The toxicity induced bychloronitrobenzenes includes hematoxicity sphenotoxicityhepatotoxicity [34ndash36] and immunotoxicity [37 38]

Therefore in this paper we report the photocatalytictransformation of three selected pesticide derivatives tri-fluralin (1) clodinafop-propargyl (2) and 12-dichloro-4-nitrobenzene (3) in acetonitrilewater medium catalyzed byTiO2in the presence of atmospheric oxygen and UV light

2 Experimental

21 Reagents and Chemicals The analytical standard tri-fluralin (1) clodinafop-propargyl (2) and 12-dichloro-4-nitrobenzene (3) were purchased from Sigma-Aldrich Indiaand were used without further purification Heterogeneousphotocatalytic transformation experiments were carried outusing Degussa P-25 TiO

2(Degussa AG) Degussa P25 con-

sists of 80 anatase and 20 rutile with a specific BET-surface area of 50m2 gminus1 and primary particle size of 20 nm[39] All other chemicals used in this study like acetonitrile(CH3CN) sodium sulphite (Na

2SO3) chloroform (CHCl

3)

and so forth were of analytical grade and obtained fromMerck

22 Procedure Experiments were carried out in an immer-sion well photoreactor made of Pyrex glass equipped with amagnetic bar a water circulating jacket and an opening formolecular oxygen A detailed description of photocatalyticreactor was documented in our previous paper [40] In atypical run TiO

2(Degussa P25 15 gLminus1) was added to ace-

tonitrilewater (1 6) solution of trifluralin (122mM 180mL)or clodinafop-propargyl (122mM 180mL) or 12-dichloro-4-nitrobenzene (124mM 180mL) The suspensions werecontinuously purgedwithmolecular oxygen throughout eachexperiment Irradiations were carried out using a 125Wmedium pressure mercury lamp (Philips) placed at thecentre of the inner jacket The light intensity was measuredat the inner wall of the annular reactor using UV-lightintensity detector (LutronUV-340) andwas found in between192 and 195mWcm2 IR-radiations were eliminated by awater jacket Aliquots (10mL) were withdrawn at differenttime intervals and filtered using Whatman grade number1 filter paper to remove the TiO

2particles The filtrate

was extracted at least thrice with chloroform (10mL) anddried over anhydrous sodium sulphate and the solvent wasremoved under reduced pressure to give a residual massThe formation of products was followed using thin-layerchromatography technique and then finally analyzed by GC-MS analysis technique CHCl

3was used to reconstitute the

sample of trifluralin and clodinafop-propargyl for GC-MSanalysis whereasCH

3CNwas used as solvent for 12-dichloro-

4-nitrobenzene

Chromatography Research International 3

Table 1 Probable products formed during the photocatalytic degradation of trifluralin (1) along with their retention time and correspondingmass fragmentation

Retention time(min) Name Confirmed by Mass fragmentation

9426-Dinitro-NN-dipropyl-4-(trifluoromethyl)aniline(1)

NIST 335142 (M+) 318138 306136307105 290105264076265053 248054 206051 160049 145035

992-Ethyl-7-nitro-5-(trifluoromethyl)-1H-benzo[d]imidazole(12)

NIST 259157 (M+) 241123 227105 213095 207014 199073186098 158187 147827 114459 99536 54368

1102-Ethyl-7-nitro-1-propyl-5-(trifluoromethyl)-1H-benzo[d]imidazole(9)

NIST 301134 (M+)302143 282140 272098 258078243087244094 212077213083 159043 145037

1277-Amino-2-ethyl-1-propyl-5-(trifluoromethyl)-1H-benzo[d]imidazole3-oxide (7)

MS 287150 (M+)288159 258113259124 245103 23082217069 202083

1293-(2-(Hydroxyamino)-6-nitro-4-(trifluoromethyl)phenylamino)propan-1-ol(10)

MS 295164 (M+)296177 280140 266123 25211123111239112 225095

1302-Ethyl-1-propyl-5-(trifluoromethyl)-1H-benzo[d]imidazol-7-amine(11)

MS 271155 (M+)272160 256131 242113 229104228097

1523-(26-Dinitro-4-(trifluoromethyl)phenylamino)propan-1-ol(6)

MS 310171 (M+) 295153 283159284162 268134 254116240101 227102 213089214091 185057

Note that the number in the parenthesis corresponds to the number of the compound in the degradation scheme

23 Analysis For GC-MS analysis AccuTOF-GCv (JMS-T100GCv) system from Jeol Asia equipped with Agilent 7690GC was used The GC column for separation was a HP-530m long and 025mm internal diameterThe film thicknesswas 025120583m The column temperature programme used was100∘C initially with an isothermal hold time for 5min andthen rose to 280∘C at a ramp of 10∘Cmin The injectortemperature was 250∘C and the injection volume was 04120583Lwith a split ratio of 1 50 The interface temperature wasmaintained at 280∘C The carrier gas was helium with a flowrate of 1mLmin The positive electron ionization mode wasused at 70-electron volt

3 Results and Discussion

31 Photocatalytic Transformation of Trifluralin (1) GC-MSanalysis of unirradiated and irradiated samples (6 hr and 9 hr)of trifluralin (1) is shown in Figures 1(a) 1(b) and 1(c) respec-tively Figure 1(a) indicates a single peak at retention time(119877119905) 94 corresponding to trifluralin confirmed by comparing

molecular ion and mass fragmentation pattern with NISTlibrary Figures 1(b) and 1(c) indicate formation of severalintermediate products on irradiation of trifluralin in thepresence of TiO

2 It is interesting to note that on prolonged

irradiation of trifluralin for 9 hours concentration of fewintermediates decreases whereas some additional intermedi-ates are formed Few products that were characterized based

on molecular ion on mass fragmentation patterns and alsoon comparison with NIST library are shown in Table 1

The probable degradation pathway of trifluralin (1) underphotocatalytic conditions showing the formation of variousproducts is shown in Scheme 1 The complete reduction ofone of the nitro groups of 1 to amino group leads to theformation of 4 Partial reduction of nitro group of 4 givesnitroso derivative 8 which upon cyclization and subsequentloss of water molecule leads to the formation of product 11Cyclization of 4 prior to reduction of nitro group leads toN-oxide derivative 7 Similarly partial reduction of one of thenitro groups of 1 leads to intermediate 5 which upon furtherloss of water molecule gives benzimidazole derivative 9 Lossof N-propyl group of 9 leads to the formation of 12 The for-mation of benzimidazoles (9 11 and 12) and benzimidazole-N-oxide derivative 7 was not unexpected Previous studieshave shown that N-alkyl-o-nitroanilines are readily cyclisedto form benzimidazoles and benzimidazole-N-oxides uponirradiation at 2537 A and upon irradiation through Pyrex[41 42] The entire aspects of chemical interaction betweenaromatic nitro groups and ortho side chains had been thesubject of a review by Preston and Tennant [43] Alternativelyloss of one of the propyl groups and hydroxylation of anotheralkyl group of 1 may lead to 6 Partial reduction of oneof the nitro groups of 6 gives 10 It is worth mentioningthat dealkylation and reduction of nitro group to amino vianitroso under photocatalytic conditions are well documentedin the literature [7 11 44ndash46]


Scheme 1 Probable pathway for the degradation of trifluralin (1) catalyzed by TiO2in the presence of UV light

32 Photocatalytic Transformation of Clodinafop-Propargyl(2) Figures 2(a) and 2(b) show the gas chromatogram ofunirradiated and irradiated sample (3 hr) of clodinafop-propargyl (2) respectively The single peak at retention time(119877119905) of 229min in Figure 2(a) corresponds to clodinafop-

propargyl confirmed by comparing its molecular ion andmass fragmentation pattern with those in NIST libraryFigure 2(b) shows the gas chromatogram of clodinafop-propargyl after irradiation for three hours indicating theformation of several intermediate products along with someunchanged starting material The structures of eight degra-dation products have been confirmed on the basis of theirmolecular ion and mass fragmentation patterns shown inTable 2

The formation of these products during photocatalyticdegradation of clodinafop-propargyl 2 can be understood interms of the pathway shown in Scheme 2 The main reactionroutes for the degradation involve dehalogenation aromaticring substitution reduction of triple bond to double bondand cleavage of ether linkage

Loss of fluorine in 2 followed by hydroxylation may leadto the formation of 13 which in turn may form product 16by the loss of pyridyl moiety via cleavage of the ether linkageAlternatively demethylation and the loss of propargyl alcoholradical followed by hydroxylation lead to product 14 Cleav-age of the ether linkage in 14 may lead to the formation of5-chloro-3-fluoropyridin-2-ol (17) and 2-phenoxyacetic acid(18) Loss of acetic acid moiety of 14 may give product 19


Table 2 Probable products formed during the photocatalytic degradation of clodinafop-propargyl (2) along with their retention time andcorresponding mass fragmentation

RetentionTime (min) Name Confirmed By Mass fragmentation

241

Prop-2-ynyl2-(4-(5-chloro-3-hydroxypyridin-2-yloxy)phenoxy)propanoate(13)

MS346934 (M+)348926 310977 281030264022266022 235985 219987 207977 179996172055 146055 127986 99903 90983 72570 62376

240Allyl 2-(4-(5-chloro-3-fluoropyridin-2-yloxy)-2-hydroxyphenoxy)propanoate(20)

MS366986 (M+)368852 266016268014237979238985 221978 209977 176026 159034129981 90894

239Allyl 2-(4-(3-fluoro-5-hydroxypyridin-2-yloxy)phenoxy)propanoate(21)

MS 333962 (M+) 226014228012 198932 183971 170949154030 138009 124974 110962 92868

2292-Propynyl (R)-2-[4-(5-chloro-3-fluoro-2-pyridinyloxy)phenoxy]propionate(clodinafop-propargyl) (2)

NIST348943 (M+)350912351911 310992 26632268014251997 237995239977 221978 209976 204010181988 176025 159034 129980 109936 9089475672 62374

1762-(4-(5-Chloro-3-fluoropyridin-2-yloxy)phenoxy)acetaldehyde(14)

MS 281083 (M+) 237977238996240983 210984176025177028 149033 129982 80755 62375

1624-(5-Chloro-3-fluoropyridin-2-yloxy)phenol(19)

MS237979 (M+)238996240983 210984 204010176029177028 156031 149032 129980 10898293875 80755 75660 64444

139 Prop-2-ynyl2-(4-hydroxyphenoxy)propanoate (16) MS 220039 (M+)221043 137056138060 109994111003

80755 6444459 2-Phenoxyacetic acid (18) MS 152038 (M+) 109994 8075538 5-Chloro-3-fluoropyridin-2-ol (17) MS 146983 (M+)148979 118976120986 91831 56180Note that the number in the parenthesis corresponds to the number of the compound in the degradation scheme

Table 3 Probable products formed during the photocatalytic degradation of 12-dichloro-4-nitrobenzene (3) along with their retention timeand corresponding mass fragmentation

Retention time(min) Name Confirmed By Mass fragmentation

166 12-Bis(34-dichlorophenyl)diazene (27) NIST 318 (M+)319947 1729751749 1449631469 10898475021

83 Dichloronitrophenol (22) NIST206957 (M+)2089210970 1769911789 160969148969 132969134967 124989 112989 9698686969 72986 62016

67 2-Chloro-5-nitrophenol (23) NIST 172990 (M+)174990 142992144992 126995 10701198994 91012 72979 63018 53001

66 34-Dichloroaniline (25) NIST 16098 (M+)1629164979 126008 98995 9002763 34-Dichlorophenol (24) NIST 161967 (M+)1639165962 144707 98995 63020

62 12-Dichloro-4-nitrobenzene (3) NIST190987 (M+)192978194970 160974162971144983146974 1329721339 108995110987 83978740167502473001 50017


which in turn may form 17 by the expulsion of phenoxideradical The difference of 18 mass units between 20 (mz367) and 2 (mz 349) suggests that before hydroxylationprecursor compound 15 is formed via the partial reductionof triple bond to double bond Alternatively dechlorinationof 15 followed by hydroxylation may lead to the formation ofproduct 21 It is interesting to note that compounds 13 and17 have also been reported to be formed during the direct

photolysis of 2 on glass surface under sunlight and UV light[47]

33 Photocatalytic Transformation of 12-Dichloro-4-Ni-trobenzene (3) Gas chromatograms of unirradiatedand irradiated samples (3 and 9 hr) of 12-dichloro-4-nitrobenzene (3) are shown in Figures 3(a) 3(b) and 3(c)respectively It is obvious from Figure 3(a) that unirradiated


(1)94

Intensity (57006869)

Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106

(a) Unirradiated trifluralin

94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103

(b) Irradiated sample (6 hr)

Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103

(c) Irradiated sample (9 hr)

Figure 1 Gas chromatogram of trifluralin (1) (a) unirradiatedtrifluralin (b) irradiated mixture (6 hr) and (c) irradiated mixture(9 hr)

(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16

(a) Unirradiated clodinafop-propargyl

(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16


Figure 2 Gas chromatogram of clodinafop-propargyl (2) (a)unirradiated clodinafop-propargyl (b) irradiated sample (3 hr)

sample of compound 3 shows a single peak at a retentiontime (119877

119905) of 62 minutes corresponding to 12-dichloro-4-

nitrobenzene confirmed by comparing its molecular ion andmass fragmentation pattern with those in NIST library Gaschromatogram of the irradiated sample (3 hours) indicatesthe formation of several degradation products along withsome unchanged startingmaterialThe prolonged irradiationfor nine hours shows increase in the concentration of few

(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16

(a) Unirradiated 12-dichloro-4-nitrobenzene

(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52


Figure 3 Gas chromatogram of 12-dichloro-4-nitrobenzene (3)(a) unirradiated 12-dichloro-4-nitrobenzene (b) irradiated sample(3 hr) and (c) irradiated sample (9 hr)

products as well as formation of several new products Thestructure of few products corresponding to peaks at retentiontimes (119877

119905) of 63min 66min 67min 83min and 166min

has been confirmed on the basis of their molecular ionon mass fragmentation pattern and also on comparison oftheir mass fragmentation data with that in NIST libraryThe molecular ion and mass fragmentation pattern of12-dichloro-4-nitrobenzene and its different degradationproducts are shown in Table 3 The probable pathwayshowing the transformation of 12-dichloro-4-nitrobenzeneinto various intermediate products in the presence of TiO

2

in acetonitrile water mixture is shown in Scheme 3The main routes of transformation of 12-dichloro-4-

nitrobenzene under photocatalytic conditions were found tobe dehalogenation denitration hydroxylation and dimeriza-tion Thus the direct hydroxylation of 3may give 22 whereassubstitution of one of the chlorines by hydroxyl group leadsto 23

Alternatively denitration of 3 followed by hydroxylationmay give dichlorophenol 24 Complete reduction of nitrogroup of 3 to amino group via nitroso derivative 26 givesdichloroaniline derivative 25 Reaction of 25 with nitrosoderivative 26 followed by loss of water gives diazene deriva-tive 27 It is interesting to note that reduction of nitro groupto amino via nitroso under photocatalytic conditions is welldocumented in the literature [11 44ndash46]


2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O

+eminusminusC5H3NClO

+H+

+H+

+eminusminusC3H3Ominus2eminus 2H+

+eminusminusCH2 CO2H

+H+

+eminus +eminusminusClminus

+eminusminusCH3+H

+

hTiO2

HOminus

+eminusminusFminusHOminus

HOminus

HOminus

∙

∙

∙

+eminusminusC 6H5O∙

Scheme 2 Possible route for the degradation of clodinafop-propargyl (4) in CH3CNH

2Omedium catalyzed by TiO

2in the presence of UV

light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O

+eminusminus2H2O6(eminus H+)

4(eminus H+ )

2(eminus H+)+eminusminusClminus +eminusminusNO2minus

hTiO2

HOminus HOminusHOminus

Scheme 3 Probable phototransformation of 12-dichloro-4-nitrobenzene (3) in CH3CNH

2O medium catalyzed by TiO

2in the presence of

UV light


4 Conclusion

Photocatalytic transformation of organic pollutants is animportant factor to understand their fate and environmentalbehavior The three pesticide derivatives studied underwentphotocatalytic degradation and comprehensive pathways oftransformation were proposed by identification of interme-diate products The GC-MS technique proved efficient forthe detection and identification of the formed degradationproducts The photocatalytic degradation of pesticides ofdifferent chemical structures demonstrated markedly differ-ent degradation pathways Loss of alkyl groups halogen(s)cleavage of alkoxy and ester bonds denitration oxidation ofside chain cyclization and reduction of alkyne to alkene andnitro to amino groupwere found to be the typical degradationroutes The study is essential in revealing the extent ofphotostability and the precise reactionmechanisms of photo-catalytic transformation of pesticides and contributes to theapt understanding of environmental behavior of pesticides

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

Financial supports from UGC New Delhi and CSTUPLucknow for Research Project Grants DRS-1 (SAP) fromUGC New Delhi to the Department of Chemistry Ali-garh Muslim University Aligarh and the Award of SeniorResearch Fellowship from UGC New Delhi to Niyaz AMir are gratefully acknowledged The authors would liketo acknowledge the support of Solid State and StructuralChemistry Unit Indian Institute of Science Bangalore Indiaand Department of Earth System Sciences Yonsei UniversityRepublic of Korea

References

[1] D M Blake ldquoBibliography of work on the Photocatalyticremoval of hazardous compounds from water and air (1994)(1995) (1997) (1999) and (2001)rdquoNRELTP430-22197NationalRenewable Energy Laboratory Golden Colorado

[2] M Janus E Kusiak-Nejman and AWMorawski ldquoDetermina-tion of the photocatalytic activity of TiO2 with high adsorptioncapacityrdquo Reaction Kinetics Mechanisms and Catalysis vol 103no 2 pp 279ndash288 2011

[3] E B Azevedo A R Torres F R Aquino Neto and MDezotti ldquoTiO

2-Photocatalyzed degradation of phenol in saline

media in an annular reactor hydrodynamics lumped kineticsintermediates and acute toxicityrdquo Brazilian Journal of ChemicalEngineering vol 26 no 1 pp 75ndash87 2009

[4] R Vinu and GMadras ldquoEnvironmental remediation by photo-catalysisrdquo Journal of the Indian Institute of Science vol 90 no 2pp 189ndash230 2010

[5] J Herrmann ldquoPhotocatalysis fundamentals revisited to avoidseveral misconceptionsrdquo Applied Catalysis B Environmentalvol 99 no 3-4 pp 461ndash468 2010

[6] N A Mir M M Haque A Khan M Muneer and S Vijay-alakshmi ldquoPhotocatalytic degradation of herbicide Bentazonein aqueous suspension of TiO

2 mineralization identification

of intermediates and reaction pathwaysrdquo Environmental Tech-nology vol 35 no 4 pp 407ndash415 2014

[7] N A Mir A Khan M Muneer and S VijayalakhsmildquoPhotocatalytic degradation of a widely used insecticide Thi-amethoxam in aqueous suspension of TiO

2 adsorption kinet-

ics product analysis and toxicity assessmentrdquo Science of theTotal Environment vol 458-460 pp 388ndash398 2013

[8] A Bianco Prevot M Vincenti A Bianciotto and E PramauroldquoPhotocatalytic and photolyric transformation of chlorambenin aqueous solutionsrdquo Applied Catalysis B Environmental vol22 no 2 pp 149ndash158 1999

[9] A B Prevot E Pramauro and M De la Guardia ldquoPhotocat-alytic degradation of carbaryl in aqueous TiO

2suspensions

containing surfactantsrdquo Chemosphere vol 39 no 3 pp 493ndash502 1999

[10] S Parra V Sarria S Malato P Peringer and C PulgarinldquoPhotochemical versus coupled photochemical-biological flowsystem for the treatment of two biorecalcitrant herbicidesmetobromuron and isoproturonrdquo Applied Catalysis B Environ-mental vol 27 no 3 pp 153ndash168 2000

[11] I K Konstantinou and T A Albanis ldquoPhotocatalytic transfor-mation of pesticides in aqueous titanium dioxide suspensionsusing artificial and solar light intermediates and degradationpathwaysrdquoApplied Catalysis B Environmental vol 42 no 4 pp319ndash335 2003

[12] A P F M de Urzedo M E R Diniz C C Nascentes R RCatharino M N Eberlin and R Augusti ldquoPhotolytic degra-dation of the insecticide thiamethoxam in aqueous mediummonitored by direct infusion electrospray ionization massspectrometryrdquo Journal of Mass Spectrometry vol 42 no 10 pp1319ndash1325 2007

[13] E Gikas N G Papadopoulos F N Bazoti G Zalidis andA Tsarbopoulos ldquoUse of liquid chromatographyelectrosprayionization tandem mass spectrometry to study the degradationpathways of terbuthylazine (TER) by Typha latifolia in con-structed wetlands identification of a new ter metaboliterdquo RapidCommunications in Mass Spectrometry vol 26 no 2 pp 181ndash188 2012

[14] R P Lopes A P F M de Urzedo C C Nascentes andR Augusti ldquoDegradation of the insecticides thiamethoxamand imidacloprid by zero-valent metals exposed to ultrasonicirradiation in water medium electrospray ionization massspectrometry monitoringrdquo Rapid Communications in MassSpectrometry vol 22 no 22 pp 3472ndash3480 2008

[15] Reregistration Eligibility Decision Trifluralin 1996[16] R Grover J D Wolt A J Cessna and H B Schiefer

ldquoEnvironmental fate of trifluralinrdquo Reviews of EnvironmentalContamination and Toxicology vol 153 pp 1ndash64 1997

[17] USDA National Agricultural Statistics Service Agriculturalchemical usage 2001 Field Crop Summary 2002

[18] GW Probst J B Tepe P C Kearney and D D Kaufman ldquoTri-fluralin and related compoundsrdquo in Degradation of Herbicidespp 255ndash282 Marcel Dekker New York NY USA 1969

[19] GW Probst T Golab and LWWrightHerbicides ChemistryDegradation andMode of Action Marcel Dekker NewYork NYUSA 1975

[20] G W Probst T Golab R J Herberg et al ldquoFate of trifluralinin soils and plantsrdquo Journal of Agricultural and Food Chemistryvol 15 no 4 pp 592ndash599 1967


[21] S A Greene and R P Pohanish Sittigs Handbook of Pesticidesand Agricultural Chemicals William Andrew Publishing NewYork NY USA 2005

[22] L S Brar U S Walia and B K Dhaliwal ldquoBioefficacy of newherbicides for the control of resistant phalaris minor in wheatrdquoPesticide Research Journal vol 11 no 2 pp 177ndash180 1999

[23] R E Blackshaw G Semach and T Entz ldquoPostemergencecontrol of foxtail barley (Hordeum jubatum) seedlings in springwheat (Triticum aestivum) and flax (Linum usitatissimum)rdquoWeed Technology vol 12 no 4 pp 610ndash616 1998

[24] MAiroldi U D Alberti andH T R Gut ldquoNew postemergencegraminicide forwheatrdquo Informatore Fitopatologico vol 47 pp57ndash60 1997

[25] C E Bell ldquoField evaluation of MKH-6561 for Phalaris minorcontrol in durum wheatrdquo in Proceedings of the Brighton CropProtection Conference Weeds pp 211ndash216 1999

[26] U S Walia L S Brar and B K Dhaliwal ldquoPerformanceof Clodinafop and Fenoxapropp-ethyl for control of resistantPhalaris minor in wheatrdquo Indian Journal of Weed Science vol30 pp 48ndash50 1998

[27] P Barnwell and A H Cobb ldquoGraminicide antagonism bybroadleaf weed herbicidesrdquo Pesticide Science vol 41 no 2 pp77ndash85 1994

[28] A V Toole D G Crosby and S Simons ldquoDissipation ofFenoxaprop ethyl under different conditionsrdquo EnvironmentalToxicology and Chemistry vol 8 pp 1171ndash1176 1999

[29] R E Alcock A Sweetman and K C Jones ldquoAssessment oforganic contaminant fate in waste water treatment plants Iselected compounds and physicochemical propertiesrdquo Chemo-sphere vol 38 no 10 pp 2247ndash2262 1999

[30] National Toxicology Program ldquoNTP technical report on toxi-city studies of 2-chloronitrobenzene and 4-chloronitrobenzeneadministered by inhalation to F344N rats and B6C3F1 micerdquoToxicity Report Series No 33 NIH Publication No 93ndash33821993

[31] D E Rickert and S D Held ldquoMetabolism of chloronitroben-zenes by isolated rat hepatocytesrdquo Drug Metabolism and Dispo-sition vol 18 no 1 pp 5ndash9 1990

[32] A G Livingston and A Willacy ldquoDegradation of 34-dichloroaniline in synthetic and industrially produced wastew-aters by mixed cultures freely suspended and immobilized ina packed-bed reactorrdquo Applied Microbiology and Biotechnologyvol 35 no 4 pp 551ndash557 1991

[33] M P Yurawecz and B J Puma ldquoIdentification of chlorinatednitrobenzene residues in Mississippi River fishrdquo Journal of theAssociation of Official Analytical Chemists vol 66 no 6 pp1345ndash1352 1983

[34] R S Nair F R Johannsen G J Levinskas and J B Ter-rill ldquoSubchronic inhalation toxicity of p-nitroaniline and p-nitrochlorobenzene in ratsrdquo Fundamental and Applied Toxicol-ogy vol 6 no 4 pp 618ndash627 1986

[35] R S Nair F R Johannsen G J Levinskas and J B TerrillldquoAssessment of toxicity of o-nitrochlorobenzene in rats follow-ing a 4-week inhalation exposurerdquo Fundamental and AppliedToxicology vol 7 no 4 pp 609ndash614 1986

[36] G S Travlos J Mahler H A Ragan B J Chou and JR Bucher ldquoThirteen-week inhalation toxicity of 2- and 4-chloronitrobenzene in F344N rats and B6C3F1 micerdquo Funda-mental and Applied Toxicology vol 30 no 1 pp 75ndash92 1996

[37] Q Li M Minami and H Inagaki ldquoAcute and subchronicimmunotoxicity of p-chloronitrobenzene in mice I Effect on

natural killer cytotoxic T-lymphocyte activities and mitogen-stimulated lymphocyte proliferationrdquo Toxicology vol 127 no 1ndash3 pp 223ndash232 1998

[38] Q Li M Minami T Hanaoka and Y Yamamura ldquoAcuteimmunotoxicity of p-chloronitrobenzene in mice II Effectof p-chloronitrobenzene on the immunophenotype of murinesplenocytes determined by flow cytometryrdquo Toxicology vol 137no 1 pp 35ndash45 1999

[39] R I Bickley T Gonzalez-Carreno J S Lees L Palmisano andR J D Tilley ldquoA structural investigation of titanium dioxidephotocatalystsrdquo Journal of Solid State Chemistry vol 92 no 1pp 178ndash190 1991

[40] N A Mir M M Haque A Khan K Umar M Muneer andS Vijayalakshmi ldquoSemiconductor mediated photocatalysedreaction of two selected organic compounds in aqueous sus-pensions of Titanium dioxiderdquo Journal of Advanced OxidationTechnologies vol 15 no 2 pp 380ndash391 2012

[41] D J Neadle and R J Pollitt ldquoThe photolysis of 119873-24-dinitrophenylamino-acids to give 2-substituted 6-nitrobenzimidazole 1-oxidesrdquo Journal of the Chemical SocietyC Organic Chemistry pp 1764ndash1766 1967

[42] R Fielden O Meth-Cohn and H Suschitzky ldquoThermal andphotolytic cyclisation rearrangement and denitration reac-tions of o-nitro-t-anilinesrdquo Tetrahedron Letters vol 11 no 15pp 1229ndash1234 1970

[43] P N Preston and G Tennant ldquoSynthetic methods involvingneighboring group interaction in ortho-substituted nitroben-zene derivativesrdquo Chemical Reviews vol 72 no 6 pp 627ndash6771972

[44] P Piccinini C Minero M Vincenti and E Pelizzetti ldquoPho-tocatalytic interconversion of nitrogen-containing benzenederivativesrdquo Journal of the Chemical Society - Faraday Transac-tions vol 93 no 10 pp 1993ndash2000 1997

[45] A Maldotti L Andreotti A Molinari S Tollari A Penoniand S Cenini ldquoPhotochemical and photocatalytic reductionof nitrobenzene in the presence of cyclohexenerdquo Journal ofPhotochemistry and Photobiology A Chemistry vol 133 no 1-2 pp 129ndash133 2000

[46] V Brezova P Tarabek D Dvoranova A Stako and S BiskupicldquoEPR study of photoinduced reduction of nitroso compoundsin titanium dioxide suspensionsrdquo Journal of Photochemistry andPhotobiology A Chemistry vol 155 no 1ndash3 pp 179ndash198 2003

[47] S Roy and S B Singh ldquoPhototransformation of clodinafop-propargylrdquo Journal of Environmental Science and Health BPesticides Food Contaminants and Agricultural Wastes vol 40no 4 pp 525ndash534 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


The photocatalyzed degradation of pesticides does notoccur directly to release inorganic species but through theformation of prolonged intermediates or degradation prod-ucts which can themselves be toxic and in some cases morepersistent than the original substrate [8ndash10]

Therefore detection and identification of the degradationproducts during photocatalytic treatment are important tooptimize and increase the overall efficiency of the processHowever the intricacy of the reaction pathways formation ofnumerous by-products and the broad range of concentrationand polarity of intermediated products are some of theproblems faced during analytical determination of degrada-tion products Therefore careful analytical screening usingdiverse techniques is essential to examine the various possibletransformation routes and to understand and propose thereaction pathways [11]

Due to the complexity of the electronradical inducedreactions occurring during the photocatalytic processes itis difficult to suggest a comprehensive reaction pathwayexplaining the formation of all detected intermediates How-ever a comparatively adequate number of fairly abundantdegradation products have been recognized during the pro-cess so that a probable scheme can be suggested consider-ing the common transformation processes of other organiccompounds [11] Gas chromatography coupled with massspectrometry is one of themost frequent analytical tools usedfor the detection of degradation products [12ndash14]

Trifluralin (26-dinitro-NN-dipropyl-4-(trifluorometh-yl) aniline) (1) a dinitroaniline herbicide is one of the mostcommon herbicides used to control many annual grassesand broadleaf weeds for agricultural crops [15] Trifluralin iscurrently registered inmore than 50 countries for use on over80 crops [16] It is currently the 3rd and 4th most commonlyused herbicide on cotton and soybean respectively Due to itshydrophobic nature it strongly sorbs to soil and therefore itstransport to the surface and ground water in the dissolved-phase is very limited Offsite transport mainly takes placeby soil erosion and subsequent deposition into streams andlakes or by volatilization losses following field applications[17ndash20] Trifluralin has been classified as group C possiblehuman carcinogen and possesses relatively high toxicity foraquatic organisms Moreover trifluralin is suspected to be anendocrine disruptor [21]

Clodinafop-propargyl (2-propynyl (R)-2-[4-(5-chloro-3-fluoro-2-pyridinyloxy)phenoxy]propionate) (2) is asystemic postemergence herbicide that effectively controlsisoproturon-resistant little seed canary grass biotypes(Phalaris minor Retz) along with other broad-leaved weedsof wheat (Triticum aestivum) [22ndash26] This herbicide isused in combination with a safener cloquintocet-mexylbut has an antagonistic effect with auxin-type herbicides[27] It interferes with the production of fatty acids neededfor plant growth in susceptible grassy weeds [28] Thisherbicide breaks down rapidly in soil and is mobile in soilThe toxicity data indicates that clodinafop-propargyl haslow acute oral dermal and inhalation toxicity It has beenclassified as ldquolikely to be carcinogenic to humanrdquo causingdevelopmental and fetotoxicity in rats This product hasbeen found to be moderately toxic to aquatic organisms

(human health risk assessment for the use of the new activeingredient clodinafop-propargyl on wheat United StatesEnvironmental Protection Agency Office of PreventionPesticides and Toxic Substances Washington DC)

Chloronitrobenzenes are important chemical intermedi-ates in the manufacture of dyes and agricultural pharmaceu-tical and industrial agents [29ndash33] The toxicity induced bychloronitrobenzenes includes hematoxicity sphenotoxicityhepatotoxicity [34ndash36] and immunotoxicity [37 38]

Therefore in this paper we report the photocatalytictransformation of three selected pesticide derivatives tri-fluralin (1) clodinafop-propargyl (2) and 12-dichloro-4-nitrobenzene (3) in acetonitrilewater medium catalyzed byTiO2in the presence of atmospheric oxygen and UV light

2 Experimental

21 Reagents and Chemicals The analytical standard tri-fluralin (1) clodinafop-propargyl (2) and 12-dichloro-4-nitrobenzene (3) were purchased from Sigma-Aldrich Indiaand were used without further purification Heterogeneousphotocatalytic transformation experiments were carried outusing Degussa P-25 TiO

2(Degussa AG) Degussa P25 con-

sists of 80 anatase and 20 rutile with a specific BET-surface area of 50m2 gminus1 and primary particle size of 20 nm[39] All other chemicals used in this study like acetonitrile(CH3CN) sodium sulphite (Na

2SO3) chloroform (CHCl

3)

and so forth were of analytical grade and obtained fromMerck

22 Procedure Experiments were carried out in an immer-sion well photoreactor made of Pyrex glass equipped with amagnetic bar a water circulating jacket and an opening formolecular oxygen A detailed description of photocatalyticreactor was documented in our previous paper [40] In atypical run TiO

2(Degussa P25 15 gLminus1) was added to ace-

tonitrilewater (1 6) solution of trifluralin (122mM 180mL)or clodinafop-propargyl (122mM 180mL) or 12-dichloro-4-nitrobenzene (124mM 180mL) The suspensions werecontinuously purgedwithmolecular oxygen throughout eachexperiment Irradiations were carried out using a 125Wmedium pressure mercury lamp (Philips) placed at thecentre of the inner jacket The light intensity was measuredat the inner wall of the annular reactor using UV-lightintensity detector (LutronUV-340) andwas found in between192 and 195mWcm2 IR-radiations were eliminated by awater jacket Aliquots (10mL) were withdrawn at differenttime intervals and filtered using Whatman grade number1 filter paper to remove the TiO

2particles The filtrate

was extracted at least thrice with chloroform (10mL) anddried over anhydrous sodium sulphate and the solvent wasremoved under reduced pressure to give a residual massThe formation of products was followed using thin-layerchromatography technique and then finally analyzed by GC-MS analysis technique CHCl

3was used to reconstitute the

sample of trifluralin and clodinafop-propargyl for GC-MSanalysis whereasCH

3CNwas used as solvent for 12-dichloro-

4-nitrobenzene





NIST 335142 (M+) 318138 306136307105 290105264076265053 248054 206051 160049 145035


NIST 259157 (M+) 241123 227105 213095 207014 199073186098 158187 147827 114459 99536 54368


NIST 301134 (M+)302143 282140 272098 258078243087244094 212077213083 159043 145037


MS 287150 (M+)288159 258113259124 245103 23082217069 202083


MS 295164 (M+)296177 280140 266123 25211123111239112 225095


MS 271155 (M+)272160 256131 242113 229104228097


MS 310171 (M+) 295153 283159284162 268134 254116240101 227102 213089214091 185057



















241


MS346934 (M+)348926 310977 281030264022266022 235985 219987 207977 179996172055 146055 127986 99903 90983 72570 62376


MS366986 (M+)368852 266016268014237979238985 221978 209977 176026 159034129981 90894


MS 333962 (M+) 226014228012 198932 183971 170949154030 138009 124974 110962 92868


NIST348943 (M+)350912351911 310992 26632268014251997 237995239977 221978 209976 204010181988 176025 159034 129980 109936 9089475672 62374


MS 281083 (M+) 237977238996240983 210984176025177028 149033 129982 80755 62375


MS237979 (M+)238996240983 210984 204010176029177028 156031 149032 129980 10898293875 80755 75660 64444















(1)94


Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106


94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103


Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103



(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16


(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16






(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16


(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52






2





2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





NIST 335142 (M+) 318138 306136307105 290105264076265053 248054 206051 160049 145035


NIST 259157 (M+) 241123 227105 213095 207014 199073186098 158187 147827 114459 99536 54368


NIST 301134 (M+)302143 282140 272098 258078243087244094 212077213083 159043 145037


MS 287150 (M+)288159 258113259124 245103 23082217069 202083


MS 295164 (M+)296177 280140 266123 25211123111239112 225095


MS 271155 (M+)272160 256131 242113 229104228097


MS 310171 (M+) 295153 283159284162 268134 254116240101 227102 213089214091 185057



















241


MS346934 (M+)348926 310977 281030264022266022 235985 219987 207977 179996172055 146055 127986 99903 90983 72570 62376


MS366986 (M+)368852 266016268014237979238985 221978 209977 176026 159034129981 90894


MS 333962 (M+) 226014228012 198932 183971 170949154030 138009 124974 110962 92868


NIST348943 (M+)350912351911 310992 26632268014251997 237995239977 221978 209976 204010181988 176025 159034 129980 109936 9089475672 62374


MS 281083 (M+) 237977238996240983 210984176025177028 149033 129982 80755 62375


MS237979 (M+)238996240983 210984 204010176029177028 156031 149032 129980 10898293875 80755 75660 64444















(1)94


Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106


94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103


Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103



(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16


(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16






(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16


(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52






2





2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










241


MS346934 (M+)348926 310977 281030264022266022 235985 219987 207977 179996172055 146055 127986 99903 90983 72570 62376


MS366986 (M+)368852 266016268014237979238985 221978 209977 176026 159034129981 90894


MS 333962 (M+) 226014228012 198932 183971 170949154030 138009 124974 110962 92868


NIST348943 (M+)350912351911 310992 26632268014251997 237995239977 221978 209976 204010181988 176025 159034 129980 109936 9089475672 62374


MS 281083 (M+) 237977238996240983 210984176025177028 149033 129982 80755 62375


MS237979 (M+)238996240983 210984 204010176029177028 156031 149032 129980 10898293875 80755 75660 64444















(1)94


Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106


94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103


Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103



(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16


(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16






(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16


(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52






2





2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




241


MS346934 (M+)348926 310977 281030264022266022 235985 219987 207977 179996172055 146055 127986 99903 90983 72570 62376


MS366986 (M+)368852 266016268014237979238985 221978 209977 176026 159034129981 90894


MS 333962 (M+) 226014228012 198932 183971 170949154030 138009 124974 110962 92868


NIST348943 (M+)350912351911 310992 26632268014251997 237995239977 221978 209976 204010181988 176025 159034 129980 109936 9089475672 62374


MS 281083 (M+) 237977238996240983 210984176025177028 149033 129982 80755 62375


MS237979 (M+)238996240983 210984 204010176029177028 156031 149032 129980 10898293875 80755 75660 64444















(1)94


Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106


94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103


Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103



(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16


(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16






(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16


(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52






2





2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(1)94


Time (min)0 2 4 6 8 10 12 14 16 18

0

20

40

times106


94

110

127

129

130

152 173

Intensity (1611187)

84

(6)

(11)

(7)

(9)

Time (min)0 2 4 6 8 10 12 14 16 18

0

1000

times103


Intensity (1845748)

Time (min)0

33 8494

99(12)

110

(10)123129 177

2 4 6 8 10 12 14 16 180

1000

times103



(2)229


0

20

40

60times10

6

Time (min)0 2 4 6 8 18 20 22 2414 16


(17) (18) (16)

(19)

(14) (20)

(13)(21)38 59 75 139

162

176

229

240

239 241


0

20

40

times106

Time (min)0 2 4 6 8 18 20 22 2414 16






(3)62Intensity (47792784)

0

20

40

times106

Time (min)0 2 4 6 8 10 12 14 16


(3)

(22)(24)

62

63 83 102 11152


010203040times10

6

Time (min)0 2 4 6 8 10 12 14 16


(24) (25)(23)(22)

(27)

636683

8467

96106

102

111

116

166

Intensity (4126390)

0

100

200

300

400times10

4

Time (min)0 2 4 6 8 10 12 14 16

52






2





2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


2

13

16 17

14

+

18

19 20 21

OOH

OH OH

OH

O

ON

F

OOO

ON

FCl

OOO

ON

OH

OOO

HOHO

OOO

ON

FClClCl

Cl Cl

ClON

F

N OH

F

OOO

ON

F OOO

ON

F

15

OO

ab

ab

CH3CNH2O


+H+

+H+



+H+


+eminusminusCH3+H

+

hTiO2

HOminus


HOminus

HOminus

∙

∙

∙





light

O2N

O2N

Cl

Cl

OH ON

HO

HO

NN

3

22 23 24 25 26

27

CH3CNH2O

Cl Cl Cl

Cl

Cl

ClCl

Cl

Cl

Cl Cl

ClCl O2N H2N

minusH2O

minusH2O

minusH2O


4(eminus H+ )


hTiO2




2in the presence of

UV light


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


4 Conclusion




Acknowledgments


References












2 adsorption kinet-




2suspensions



















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Documents

Research Article Photocatalytic Degradation of Trifluralin ... · e toxicity data indicates that clodinafop-propargyl has low acute oral, dermal, and inhalation toxicity. It has been