Synthesis of 1,2,3-Triazole Derivatives and Its Evaluation...

Research ArticleSynthesis of 123-Triazole Derivatives and Its Evaluation asCorrosion Inhibitors for Carbon Steel

Gabriel O Resende1 Sara F Teixeira2 Igor F Figueiredo1 Alexandre A Godoy2

Dafne Juacutelia F Lougon2 Bruno A Cotrim 1 and Flaacutevia C de Souza 2

1 Instituto Federal de Educacao Ciencia e Tecnologia do Rio de Janeiro Campus Rio de Janeiro 20270-021 Rio de Janeiro RJ Brazil2Instituto Federal de Educacao Ciencia e Tecnologia do Rio de Janeiro Campus Sao Goncalo 24425-005 Sao Goncalo RJ Brazil

Correspondence should be addressed to Flavia C de Souza flaviasouzaifrjedubr

Received 1 November 2018 Accepted 8 January 2019 Published 22 January 2019

Academic Editor Adalgisa Rodrigues de Andrade

Copyright copy 2019 Gabriel O Resende et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Heterocyclic compounds containing the 123-triazole moiety can be synthesized through click-chemistry which is rapid reactionswith good yields allowing the synthesis of great derivatives diversity by making minor changes in the reagents The products wereobtained with good yields through a synthetic route which uses ready available nonexpensive commercial reagents and withoutany further purification of any product or intermediate The carbon steel anticorrosive activity was tested through weight lossand electrochemical assays in acid media It was observed relevant inhibition efficiency (gt 90) for inhibitors 1 and 2 FromLangmuir isotherm it was hypothesized the adsorption of inhibitors on the carbon steel surface might occur by physical andchemical interaction however the activation energy raised suggests a physisorption process for the interaction of the inhibitor onthe carbon steel surface

1 Introduction

Heterocyclic compounds have a great diversity of physicalchemistry and biological properties which provide them awide range of practical uses This chemistry class is largelyused in the pharmaceutical industry both in commercialproducts and in research and development andmore recentlythey are gaining attention in researches for the developmentof new anticorrosive compounds [1 2]

Compounds containing 124-triazole moiety are widelystudied as anticorrosive for copper [3ndash5] and mild steel inhydrochloric acid [6ndash8] phosphoric acid [9] and nitric acid[9] Although not widely studied the use of 123-triazolederivatives as an anticorrosive for steel [10 11] can be foundin the literature

Compounds containing the 123-triazole moiety can besynthesized through click-chemistry which is rapid reactionswith good yields allowing the synthesis of a great derivativesdiversity by making minor changes in the reagents Thecopper-catalyzed 13-dipolar cycloaddition reaction betweenan azide and an alkyne is widely used for the synthesisof compounds with the 123-triazole ring with substituents

in position 4 [12] Other methodology for the synthesis ofthis class of compounds is the reaction of an azide withmethylenic activated compounds using different catalystsgenerating a triazol with substituents in positions 4 and 5 [13]

The objective of the present work is the synthesis of123-triazole derivatives (Figure 1) and evaluation of theiractivity as corrosion inhibitor for carbon steel in corrosiveenvironments

2 Experimental

Reactions progress was monitored by TLC on aluminumsheets precoated with silica gel 60 (HF-254 Merck) filmthickness of 025mm Nuclear magnetic resonance (1H and13C NMR) spectra were recorded using a Varian 500MHzinstrument For the 1H NMR spectra chemical shifts (120575) arereferenced from tetramethylsilane (TMS 000 ppm) and thecoupling constants (J) are reported in Hz Fourier transforminfrared (FT-IR) spectra of triazole derivatives were obtainedat 25∘C in a Bruker Alpha spectrophotometer using theattenuated total reflectance (ATR) module

HindawiInternational Journal of ElectrochemistryVolume 2019 Article ID 6759478 12 pageshttpsdoiorg10115520196759478

2 International Journal of Electrochemistry

NH2

N

N

N

HO

1

NH2

N

N

N

HO

2

NH2

N

N

N

EtO

O

3

Figure 1 123-Triazole derivatives structures

All reagents and solvents used were commercially avail-able and were employed without further purification unlessspecifically indicated

21 Inhibitor Synthesis

Synthesis of 1-azido-4-nitrobenzene (5) In a flask previouslycontaining HCl 6N (30mL) p-nitroaniline (3 g 2174mmol)was added with magnetic stirring at room temperatureAfterwards a solution of NaNO2 (15 g 2174mmol) in 20mLof water was added dropwise controlling the temperature at5-10∘C The reaction was stirred for 1 h at room temperatureand a solution of NaN3 (141 g 2174mmol) in 20mL of waterwas added slowly under vigorous stirring The reaction wasfollowed by thin layer chromatography (TLC) and productwas filtered washed with water and dried The product wasobtained as a yellowish solid yield 90 (32 g)

FT ATR IR 3069 (C-H ar st) 2120 (N3 st) 1590 (ar C=Cst) 1512 (C-NO2 ass st) 1287 (C-NO2 sym st)

Synthesis of (1-(4-nitrophenyl)-1H-123-triazol-4-yl)methanol(7) To a suspension of (5) (12 g 732mmol) in terc-butanol(5mL) was added a mixture of ascorbic acid (281mg16mmol) CuSO45H2O (145mg 058mmol) and NaHCO3(135mg 16mmol) in 55mL of water Afterwards propar-gylic alcohol (052mL 9mmol) was added and the reactionmixture was stirred for 24-48 h at room temperature Thereaction was followed by TLC and the product was obtainedby filtration washed with water and dried The product wasobtained as a brownish solid and was used without furtherpurification in next step yield 78 (125 g)

FT-IR (ATR) 3436 (O-H st) 1598 (ar C=C st) 1510 (C-NO2 ass st) 1287 (C-NO2 sym st)

Synthesis of (1-(4-aminophenyl)-1H-123-triazol-4-yl)methanol(1) To a suspension of (7) (154 g 70mmol) in water(40mL)NH4Cl (750mg 14mmol) and zinc powder (3325g508mmol) were addedThe reaction mixture was stirred and

heated to 80∘C during 3 hours The resulting mixture was fil-tered and washed with dichloromethane The aqueous phasewas extracted with dichloromethane five times The organicphase was dried over Na2SO4 filtered and concentrated toobtain the product as a pinkish solid yield of 68 (090 g)

FT-IR (ATR) 3462 (O-H st) 3362 (N-H st) 1631 (ar C=Cst) 860 (ar C-H 120575)1H NMR (500MHz DMSO-1198896) 120575 828 (s 1H) 745-743

(d J=90Hz 2H) 671-669 (d J=85Hz 2H) 532 (s 2H)505 (s 1H) 458 (s 2H)13CNMR (225MHz DMSO-1198896) 120575 14922 14848 12626

12154 12062 11393 5506

Synthesis of ethyl 1-(4-nitrophenyl)-5-methyl-1H-123-triazole-4-carboxylate (6) To a round bottom flask of 50mL wereadded 276mg (2mmol) of compound 5 and 1mL of DMF andthe solid was solubilized with magnetic stirrer at room tem-perature Afterwards 06mL of trimethylamine and 055mLof ethyl acetoacetate were added to the flask The reactionmixture was stirred at room temperature for 24 hours Thereaction was followed by thin layer chromatography Thework up of the product was made through filtration Thereaction had a yield of 94 (436mg) brownish solid

FT ATR IR 3080 (C-H ar st) 2976 (C-H aliph st) 1711(C=O st) 1530 (C-NO2 assym st) 1343 (C-NO2 sym st) 852(ar C-H 120575)Synthesis of ethyl 1-(4-aminophenyl)-5-methyl-1H-123-tria-zole-4-carboxylate (3) In a round bottom flask of 100mLwere added 332mg (13mmol) of compound 6 50mg ofpalladium 10 supported on active charcoal 10 375mg ofammonium formate and 2mL of methanol The reactionwas maintained under nitrogen atmosphere with magneticstirring and room temperature for 24 hoursThe reaction wasfollowed by thin layer chromatography The reaction mixturewas filtered through Celite and the Celite was washed with10mL of dichloromethane The filtrate was extracted withbrine the organic phase was dried with Na2SO4 anhydrous

International Journal of Electrochemistry 3

and then distilled under reduced pressure The product wasobtained as a white solid with a yield of 832 (244mg)

FT-IR (ATR) 3345 (N-H st) 2978 (C-H st) 1702 (C=O st)1516 (ar C=C st)) 840 (ar C-H 120575)1H NMR (500MHz DMSO-1198896) 120575 717-716 (d J=90Hz

2H) 673-772 (d J=90Hz 2H) 550 (S 1H) 437-432 (qJ=75Hz 2H) 243 (s 3H) 135-132 (t J=75 3H)13C NMR (125MHz DMSO-1198896) 120575 16170 15071 13936

13593 12675 12390 11423 6067 1460 1004

Synthesis of 1-(5-methyl-1-(4-nitrophenyl)-1H-123-triazol-4-yl)ethanone (8) To a round bottom flask of 10mLwere added693mg (32mmol) of compound 5 and 17mL of DMF andthe solid was solubilized with magnetic stirrer at room tem-perature Afterwards 12mL of trimethylamine and 09mLof ethyl acetylacetone were added to the flask The reactionmixture was stirred at room temperature for 24 hours Thereaction was followed by thin layer chromatography Thework up of the product was made through filtration Theproduct was obtained as a solid powder with a 755 yield(740mg)

FT ATR IR 3076 (C-H ar st) 1677 (C=O st) 1518 (C-NO2assym st) 1341(C-NO2 sym st) 853 (ar C-H 120575)Synthesis of 1-(1-(4-aminophenyl)-5-methyl-1H-123-triazol-4-yl)ethanol (2) In a 10mL round bottom flask was addedcompound 208mg of compound 8 5mL of methanol and08mL of an aqueous saturated solution of CuSO4 In asecond flask it was prepared a solution of 190mg of NaBH4in 6mL of a mixture of watermethanol 11 Under ice bath(5-10∘C) the content of the second flask was added dropwiseto the first flask and it was observed the formation of aCuS black precipitate The reaction was followed by thinlayer chromatography The CuS precipitated was filteredand methanol was distilled under reduced pressure Theconcentrate was solubilized in ethyl acetate and extractedwith water The organic phase was dried with anhydrousNa2SO4 and the solvent was distilled under reduced pressureThe product was obtained as a purplish solid with 79 yield(144mg)

FT-IR (ATR) 3466 (O-H st) 3326 (N-H st) 2972 (C-H st)1517 (ar C=C st) 837 (ar C-H 120575)1H NMR (500MHz DMSO-1198896) 120575 710-709 (d J=85Hz

2H) 671-670 (d J=85Hz 2H) 538 (s 2H) 492-488 (m2H) 223 (s 3H) 150-149 (d J=65 3H)13C NMR (125MHz DMSO-1198896) 120575 15009 14789 13049

12640 11425 6212 2352 902

22 Gravimetric Weight Loss Carbon steel used as specimenswas cut into 30 cm times 10 cm times 10 cm sections and abradedwith emery paper of different granulometry (320 600 and1000) The chemical composition ASTM 1020 carbon steelis (wt) C (018) Mn (030) S (005) and Fe (bal-ance) These pieces were washed with double distilled waterdegreased with acetone and dried in air

Triplicate specimens were immersed in a 10mol Lndash1HCl aqueous solution prepared from 37 HCl (purchasedfrom Merck Co Darmstadt Germany) and double distilledwater in the absence and presence of corrosion inhibitors

at 250mg Lndash1 for a period of 24 h After the specimenswere removed washed with water and acetone and dried inwarm air the weight was obtained according to ASTM G31-72 [ASTM International G31-72 Standard practice for labo-ratory Immersion Corrosion Testing of Metals West Con-shohocken ASTM International 1999] (standard method)and determined using an analytical balance with a 01mgprecision The efficiency of inhibition (119864119868) was calculatedusing

119864119868 () = 1198820 minus1198821198820 times 100 (1)

where 1198820 and 119882 are the weight loss (g cmndash2 hndash1) in theabsence (blank) and presence of the corrosion inhibitorcompound respectively The corrosion rate in millimeterspenetration per year (mmy) was obtained

119882 = 119870119872119860119905 120588 (2)

where 119870 is a constant (876 times 104) 119872 is the weight loss ingrams 119860 is the specimen area in cm2 119905 is time in hour and 120588is the specific mass of carbon steel (786 g cmndash3)

The gravimetric testing was also performed at differentinhibitor concentrations (250ndash1250mg Lndash1) different immer-sion times (4 8 12 24 and 48 h) and different temperatures(25 35 45 and 55∘C)

23 Electrochemical Experiments Electrochemical measure-ments were carried out in conventional three-electrodecell (100mL) using a Microautolab IIIFRA2 (Eco ChemieUtrecht the Netherlands) coupled to a personal computerand controlled with GPES 49 software (General PurposeElectrochemical System) In all cases ASTM was used asstandard method The supporting electrolyte was the sameused in loss weight and the measurements were carried outin 100mL of nonstirred and naturally aerated electrolytemaintained at 25∘C

Carbon steel specimens with same composition usedin the gravimetric weight loss measurements were cut andemployed as work electrode with exposed surface area of078 cm2 These carbon steel electrodes also were abraded inpolitriz Aropol 2V (Arotec) with emery paper of differentgranulometry (320 400 600 and 1000) washed with doubledistilled water degreased with acetone and dried in airSaturated calomel electrode (SCE) was used as the referenceelectrode and a Pt wire with large superficial area was usedas the auxiliary electrode

Work electrode in electrochemical measurements waskept in support electrolyte during 1 h to reach its stableopen-circuit potential (OCP) Electrochemical impedancespectroscopy (EIS) was performed using the aforementionedpotentiostat over a frequency range of 100 kHz to 10mHzat the stable open-circuit potential with an AC wave of10mV (rms) Potentiodynamic polarization curves were alsoobtained after 1 h in the open-circuit potential and performedusing a scan rate equal to 1mV sndash1 from ndash300mV up to+300mV in relation to OCP


NO2

NH2

a)

NO2

N3

b)

NO2

c)

N

N

N

NH2

N

N

N

EtOEtO

O O

NO2

N

N

N

O

g)e)

NH2

N

N

N

OH

NO2

N

N

N

HO

d) f)

NH2

N

N

N

HO

4 5 6 3

12

7 8

Scheme 1 Synthetic route to triazole derivatives compounds 3ndash8 (a) (1)HClNaNO3 (2)NaN3 (b) Ethyl Acetoacetate Et3NDMF (c) PdCammonium formate (d) (1) Ascorbic Acid CuSO45H2O NaHCO3 (2) Propargylic Alcohol (e) Zn NH4ClH2O (f) Et3N Acetylacetone(g) NaBH4MeOH Cu2SO45H2O

The synthetic inhibitorswith the best inhibitory efficiency(119868119864) by gravimetric weight loss were subjected to theelectrochemical testing of OCP EIS measurements andpolarization curves The 119868119864() value was also obtainedfrom potentiodynamic polarization curves and EIS diagramsfrom

119868119864 () = 1198951198881199001199031199030 minus 1198951198881199001199031199031198951198881199001199031199030 times 100 (3)

where 1198951198881199001199031199030 and 119895119888119900119903119903 are the corrosion current densityobtained from Tafel plots in the absence and presence of aninhibitorThe 119868119864() value fromEIS diagramswas calculatedfrom

119868119864 () = 119877119888119905 minus 1198771198881199050119877119888119905 times 100 (4)

were 1198771198881199050 and 119877119888119905 are the charge transfer resistance in thepresence and absence of the inhibitor both obtained from theEIS diagrams by extrapolation of the semicircle

3 Results and Discussions

31 Inhibitor Synthesis and Characterization Synthetic routeproposed to obtain triazoles compounds was presented inScheme 1 Briefly the reaction of p-nitroaniline (4) withsodium nitrite in acidic medium and addition of sodiumazide was used to obtain compound 5 [12] The intermediate5 was reacted with ethyl acetoacetate in the presence oftriethylamine to obtain compound 7 [13] Compound 8 wasobtained from reaction of intermediate 6 with propargylalcohol catalyzed by Cu+ [12] and compound 9 from reactionof intermediate 6 with acetoacetone in the presence oftriethylamine [13] Compounds 3 and 1 were obtained fromrespective reaction of 6 7 and 8 with zinc in presence ofammonium chloride and water or PdC with ammoniumformate [14] Compound 2 was obtained from reaction ofcompound 8 with sodium borohydride in the presence ofcopper sulphate [15]


Table 1 Inhibitor efficiencies to carbon steel in 10mol Lndash1 HCl solution containing 250mg Lndash1 of commercial and proposed inhibitors afterimmersion for 24 h at 25∘C

Inhibitor 119868119864 () Error ()1 919 132 958 073 702 13Commercial 722 19

Table 2 Inhibitor efficiencies and corrosion rates to carbon steel in 10mol Lndash1 HCl solution with different concentrations of inhibitors afterimmersion for 24 h at 25∘C

Inhibitor Concentration (mg Lndash1)Inhibitor 1 Inhibitor 2 Commercial Inhibitor

119882 119868119864 Error 119882 119868119864 Error 119882 119868119864 Error(mmy) () () (mmy) () () (mmy) () ()

Blank 128 ndash ndash 128 ndash ndash 128 ndash ndash250 10 919 13 05 958 07 22 722 19500 09 934 03 04 967 03 13 829 12750 07 943 08 06 955 55 13 831 091000 06 950 05 02 982 03 13 839 071250 05 962 02 01 992 02 08 841 05

The products were obtained using synthetic route usingready available nonexpensive commercial reagents and with-out any further purification of any product or intermediateProducts were obtained in good purity as observed ininfrared and RMN analysis and yields of all synthetic stepswere good varying between 60 and 94

32 Gravimetric Weight Loss Measurements In an electro-chemical spontaneous corrosion process when the metalinteracts with electrolyte solution both anodic and cathodicreactions occur Corrosion mechanism of carbon steel in acidsolution can happen by reaction between metallic iron andH+ producing ferrous ion (Fe2+) and hydrogen gas shown asfollows [16]

Fe + H 997888rarr [FeHads]+

[FeHads]+ + eminus 997888rarr [FeHads]

[FeHads] + H+ + eminus 997888rarr Fe + H2Fe 997888rarr Fe2+ + 2eminus

The inhibition efficiency obtained from weight lossexperiments with carbon steel in acid medium is presentedin Table 1 An imidazoline based commercial corrosioninhibitor was used in same concentration to compare theinhibition efficiency of proposed inhibitors

Thedata fromTable 1 suggest that the triazole compoundsbehave as corrosion inhibitors and that their inhibitionefficiency remains high through long periods of immersion(24 h) for low inhibitor concentration Inhibitors 1 and 2showed the best inhibitions efficiencies (greater than 90)with a relative standard deviation lower than 2 Analyzingthis result we can hypothesize that the hydroxyl grouppresent in both compounds 1 and 2 and absent in compound3 could be an important group with anticorrosive activity

Additional studies as molecular docking between the syn-thesized inhibitors and the metal alloy should be done inorder to understand the structurendashactivity relationships forthe synthesized triazole corrosion inhibitors Therefore wechose inhibitors 1 and 2 to carry out further corrosion assaysand try to explain the corrosion inhibition mechanism

The rates of carbon steel corrosion in 10mol Lndash1 HClaqueous solution in the presence and absence of the bestinhibitors in concentration range of 250ndash1250mg Lndash1 for 24 himmersion at 25∘C as well as the efficiency results are shownin Table 2

The carbon steel corrosion rate (119882) shown in Table 2 wassignificantly reduced with addition of the inhibitors Thoseresults show the inhibitory effect of the triazole compoundsagainst carbon steel corrosion in low pH solutions Further-more the inhibition efficiency grew when the concentrationof triazole compounds in this medium increased It has alsobeen observed that the inhibition efficiencies of compound 2are higher when compared to those of compound 1

The corrosion process was also investigated in differentimmersion time of carbon steel in 10mol Lndash1 HCl aqueoussolution in presence and absence of 500mg Lndash1 of inhibitors(4 8 12 24 and 48 h) at room temperature and the results ofthe weight loss measurements are shown in Table 3

It can be observed in Table 3 that in solutions withoutinhibitor the uniform corrosion rate is very severe for allimmersion times (varying of 160mmy to 128mmy) andthe ratewas greatly reducedwith the addition of the inhibitorsfor all immersion times reaching 09mmy and 04mmy inthe presence of the inhibitors with 24 h of immersion Thesecorrosion rates are considered low according to Gentil (forcheap materials like carbon steel the corrosion rate could beacceptable in the range of 0225 to 15mmy) [17]


Table 3 Inhibitor efficiencies and corrosion rates to carbon steel in 10mol Lndash1 HCl aqueous solution in presence and absence of the inhibitor(500mg Lminus1) with different immersion times at 25∘C

Immersion Time (h)Blank Inhibitor 1 Inhibitor 2W W IE Error W IE Error

(mmy) (mmy) () () (mmy) () ()4 160 17 892 15 03 979 068 147 18 875 19 03 979 0212 147 16 888 07 02 987 0524 128 09 934 03 04 967 0348 142 16 886 12 03 979 02

Table 4 Values of the 120572 and 119903 of the Langmuir isotherm119870 and 1198660119886119889119904

obtained for the corrosion inhibitors

Inhibitor Parameters of Langmuir isotherm120572 119903 119870 (L mmolndash1) Δ1198660

119886119889119904(KJ molndash1)

1 1027 09999 925 ndash3362 0998 09991 1136 ndash331

80

0

60

50

40

30

20

10

000605040302010

C (m

mol

L-

)

C (mmol L-)

Inhibitor 1Inhibitor 2

Figure 2 Langmuir adsorption isotherms of triazole compounds on the carbon steel surface in 10mol Lndash1 HCl aqueous solution

Corrosion rate reduction in presence of inhibitors occursdue to the formation of protective layer by inhibitor adsorp-tion on the metallic surface To investigate the adsorptionbehavior of triazole compounds various isotherms were usedand Langmuir isothermwas the best fit with the experimentaldata from Table 2 Langmuir isotherm was obtained fromlinear correlation between the level of surface coating (120579) andinhibitor concentration (119862) The adsorption isotherm used isplotted assuming that all adsorption sites are equivalent andthat binding of particles is unaffected by any nearby occupiedor unoccupied locations In accordance with this isotherm120579119862 is related to 119862 by

119862120579 = 119862 + 1

119870 (5)

where 119870 is the adsorption equilibrium constant Figure 2shows the relationship between 119862120579 and the concentration ofinhibitors

A linear correlation can be observed in Figure 2 withsignificant correlation coefficients (119903) showing the validityof the isotherm (Table 4) The curve slope is near the unitywhich can suggest that the inhibitor adsorbedmolecules formamonolayer on carbon steel surfaceThe adsorption constant(119870) was calculated from the Langmuir intercept and relatedto the standard Gibbs free energy (1198660119886119889119904) according to

119870 = 15555 exp(

minus1198660119886119889119904119877119879 ) (6)

where 119877 is the universal gas constant 119879 is the absolutetemperature and 5555mol Lndash1 is the water molar concen-tration in solution Table 4 shows the values of the slope (120572)the correlation coefficient (119903) of the Langmuir isotherm theadsorption constant (119870) and the standard Gibbs free energy(1198660119886119889119904)

The1198660119886119889119904 values obtained from (6)wereminus336 and 331 kJmolminus1 to compounds 1 and 2 respectively Generally values of


Table 5 Inhibitor efficiencies and corrosion rates to carbon steel in 10mol Lndash1 HCl aqueous solution in absence and presence of 250mg Lndash1of inhibitors during 4 h varying temperatures

Temperature Inhibitor 119882 119868119864 Error(∘C) (mmy) () ()

25Blank 160 minus minus1 17 892 152 03 979 06




1198660119886119889119904

greater thanminus20 kJmolminus1 indicate electrostatic interac-tions attributed to inhibition interaction between the chargedcompounds and the charged metal surface (physisorption)and values equal or smaller than minus40 kJmolminus1 are related toelectrons share or electrons transfer from organic moleculesof the inhibitor to the metal surface forming a coordinatebond (chemisorption) In accordance with the 1198660119886119889119904 valuesobtained it can be hypothesized that the adsorption of bothcompounds is not only by physisorption or chemisorptionbut by obeying a comprehensive adsorption (chemisorptionand physisorption) It is difficult to differentiate betweenchemisorption and physisorption based only on these crite-ria particularly when charged species are adsorbed

The effects of temperature on the corrosion of carbonsteel in 10mol Lndash1 HCl solution in absence and presenceof 250mg Lndash1 of inhibitors were studied during 4 h varyingtemperatures (25 35 45 and 55∘C) The corrosion rates andinhibitor efficiencies obtained in this study were presented inTable 5

Table 5 shows that in solutions without inhibitor thecorrosion process is accentuated and increased with thetemperature (varying of 160mmy to 998mmy) It canbe observed that corrosion rate reduces with the additionof the inhibitors for all temperatures in the presence ofthe inhibitors and inhibition efficiencies increase Theseinhibition efficiencies stay high even at high temperatures(870plusmn03 and 946plusmn03 at 55∘C)

The apparent activation energy for carbon steel corrosionin absence and presence of 250mg Lndash1 of inhibitors wasdetermined from an Arrhenius-type plot according to

ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)

where119882119888119900119903119903 is corrosion rate 119864119886 is activation energy 119860 is thefrequency factor 119879 is the absolute temperature and 119877 is themolar gas constant Arrhenius plots of ln119882119888119900119903119903 versus 1119879in the absence and presence of 250mg Lndash1 of inhibitors areshown in Figure 3

The apparent activation energy obtained for the corrosionprocess in the acid solution was 497 kJ molndash1 and in the acidsolution in presence of 1 and 2 inhibitors were 552 and 788 kJmolndash1 respectively (Table 6) It was clear that apparent acti-vation energy increase with the presence of inhibitors com-pounds indicates the physical adsorption mechanism [18]

The corrosion inhibition process also can be explained byusing thermodynamicmodelThe adsorptionheat (1198670) andthe adsorption free entropy (1198780) were calculated by plot ofln(119882119888119900119903119903119879) versus 1119879 according to

ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)

where ℎ is the Planckrsquos constant119873 is the Avogadrorsquos number119879 is the absolute temperature and 119877 is the universal gasconstant Straight lines of ln(119882119888119900119903119903119879) versus 1119879 are plottedin Figure 4 andHandS values from the slope of (minus1198670119877)and an intercept of [(ln(119877119873ℎ) + (11987802303119877119879)] respec-tively were calculated and also listed in Table 6

The positive values of 119867 observed in Table 6 reflect theendothermic nature of the carbon steel dissolution processwhich is attributed to the slower dissolution of mild steel inthe presence of the inhibitor than in its absence The negativevalues of Δ119878 observed for uninhibited and inhibited solutiondue the activated complex in the rate determining steprepresent an association rather than dissociation resulting ina decrease in the randomness on going from the reactantsto the activated complex [19] It was clear from Table 6 datathat 119864119886 and 119867 values vary in the same way The 119867 valueswere lower than 119864119886 values and it can indicate the corrosionprocessmust involve a gaseous reaction probably a hydrogenevolution reaction associated with decrease in total reactionvolume These results fit the known thermodynamic relationbetween 119864119886 and 119867 described in

119864119886 minus 119867 = 119877119879 (9)

It was found that for the whole system the difference is260 kJ molminus1 in HCl medium This is the approximate value


Table 6 Thermodynamic parameters of corrosion inhibition process of carbon steel in 10mol Lndash1 HCl solution in absence and presence ofinhibitors

Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867

(kJ molndash1) (kJ molndash1) (J molndash1 Kndash1) (kJ molndash1)blank 5039 09910 4779 ndash1269 09918 25971 5284 09916 5022 ndash1377 09840 25972 7651 09998 7391 ndash7223 09971 2602

minus20

minus40

minus60

minus80

minus100

30times10-331times10-3


34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘

Figure 3 Arrhenius plots of lnWcorr versus 1T in the absence and presence of 250mg Lndash1 of inhibitors compounds

minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘

Figure 4 Adsorption heat (1198670) and adsorption free entropy (1198780) of triazole compounds on the carbon steel surface in 10mol Lndash1 HClaqueous solution

estimated for 119877119879 where 119879 is the range of experimentaltemperatures

33 Electrochemical Experiments

331 Potentiodynamic Polarization Curves Figure 5 showsthe potentiodynamic polarization curves of carbon steel in

10mol Lndash1 HCl solution in absence and presence of differentconcentration of inhibitors at room temperature

The potentiodynamic polarization curves show theinhibitors presence caused a significant decrease in cathodicand anodic current densitiesThese results could be explainedby the adsorption of inhibitors at the active sites of theelectrode surface which also retards the metallic dissolution


10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1

minus900 minus800 minus700 minus600 minus500 minus400 minus300 minus200 minus100

E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Figure 5 Potentiodynamic polarization curves of carbon steel in 10mol Lndash1 HCl solution in absence and presence of different concentrationsif inhibitor 1 (a) and inhibitor 2 (b)

Table 7 Electrochemical parameters of carbon steel in 10mol Lndash1 HCl aqueous in absence and presence of inhibitors at differentconcentrations

Inhibitor Inhibitor Concentration 119864119888119900119903119903 119895119888119900119903119903

119887119888 119887119886 119868119864(mg Lndash1) (mV) (mAcm2) (mVdec) (mVdec) ()

Blank ndash4964 06055 18018 10174

1

250 ndash4976 02448 52242 10508 60500 ndash5075 01157 36912 9809 81750 ndash4962 00397 13492 7877 931000 ndash4920 00295 10554 6252 95

2


and hydrogen evolution and consequently slows the cor-rosion process The electrochemical parameters ie thecorrosion potential (119864119888119900119903119903) corrosion current density (119895119888119900119903119903)and the anodic (119887119886) and cathodic (119887119888) Tafel constantsshown in Table 7 were obtained from the Tafel plots fromFigure 5

The corrosion current density (119895119888119900119903119903) decreases in thepresence of both inhibitors (Table 7) There was no remark-able shift in the corrosion potential (119864119888119900119903119903) value with respectto the blank According to literature report [20] whencorrosion potential is more than plusmn85mV with respect to thecorrosion potential of the blank the inhibitor can be consid-ered distinctively as either cathodic or anodic type Howeverthe maximum displacement in this study is less than plusmn85mV

The cathodic (119887119888) and anodic (119887119886) Tafel slopes are significantlychanged indicating that the inhibition mechanism occurredwith the addition of the inhibitors (Table 7) blocking theavailable cathodic and anodic active sites on the metalsurfaceThe change in cathodic Tafel slopes is larger than thatin anodic Tafel slopes which reveals that inhibitor moleculesare adsorbed on both sites but under prominent cathodiccontrol resulting in the inhibition of anodic dissolution andcathodic reduction The inhibition efficiency calculated fromthe j119888119900119903119903 values obtained in the absence and presence ofinhibitors varied from 60 to 95 in inhibitor 1 and 78 to 95in inhibitor 2 over a concentration range of 250ndash1000mg Lndash1These results of the inhibition efficiencies revealed a fairlygood inhibition action of synthetic inhibitors


Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)

Figure 6Nyquist diagramof carbon steel in 10mol Lndash1HCl solutionwithout (a) andwith inhibitors 1 (b) and 2 (c) at different concentrations

332 Electrochemical Impedance Spectroscopy (EIS) Thecorrosion behavior of carbon steel in 10mol Lndash1 HClin the absence and presence of triazole compounds(250ndash1000mg Lndash1) was investigated by EIS after immersionfor 1 h at room temperature and Figure 6 illustrates the elec-trochemical impedance diagrams The impedance data fromEIS experiments done in the absence and presence of increas-ing inhibitors concentrations were summarized in Table 8

The electrochemical impedance diagrams exhibit onedepressed capacitive loop which indicate a single time

constant in the absence and presence of the inhibitorsimplying two noteworthy effects the charge transfer resis-tance considerably increases and 119891119898119886119909 decreases when theinhibitors are added These aforementioned effects decreasethe capacitance values which could be caused by a decrease inthe local dielectric constant andor by a growth in the thick-ness of the electrical double layer indicating that the presenceof the triazoles compounds changes the electric double-layerstructure which can suggest the inhibitor compounds act byadsorption at the metalsolution interface The impedance


Table 8 Impedance data obtained from Nyquist diagram of carbon steel in 10 mol Lndash1 HCl solution without and with inhibitors at differentconcentrations

Inhibitor Inhibitor Concentration 119864119874119862119875

119877119888119905

119877119904

119891119898119886119909

119862119889119897

Efficiency(mg Lndash1) (V) (Ω cmndash2) (Ω cmndash2) (Hz) (120583F cmndash2) ()

Blank 0 ndash0506 17344 3599 19953 4599 ndash

1

250 ndash0504 14512 3881 3981 2755 88500 ndash0514 26185 3928 1995 3046 93750 ndash0505 47514 4233 794 4217 961000 ndash0500 56042 3646 794 3575 97

2


diagrams obtained are not perfect semicircle because ofthe frequency dispersion of the interfacial impedance Thisatypical phenomenon is attributed in the literature to thenonhomogeneity of the electrode surface rising from thesurface roughness or interfacial phenomena [21 22]

This semicircle intersection with the real axis at highfrequencies produces an ohmic resistance (119877119904) of nearly 36Ω cmndash2 of the solution The solution resistance (119877119904) is closein the absence and presence of the inhibitors compoundsThe charge transfer resistance (119877119888119905) was calculated from thevariance in impedance at lower and higher frequencies Thedouble-layer capacitance (119862119889119897) was obtained using

119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)

where 119891119898119886119909 is the frequency when the imaginary componentof the impedance is maximal A 119862119889119897 value of 460 120583F cmndash2

was found for the carbon steel electrode at 10mol Lndash1 HClaqueous solution

From Table 8 it is clear that the 119877119888119905 values increased withinhibitor concentration increment which implies a reductionin the active surface area derived by the adsorption of theinhibitors on the carbon steel surface and indicates thecorrosion process turned to be hindered This assumptionis supported by the anodic and cathodic polarization curvesresults The inhibition efficiency obtained from the 119877119888119905 valuesin the absence and presence of inhibitors varied from 88to 97 in inhibitor 1 and 94 to 98 in inhibitor 2 over aconcentration range of 250ndash1000mg Lndash1

4 Conclusions

The synthesis of triazoles compound following an easy lowcost and simplified synthetic route gave good corrosioninhibitors For this purpose a range of 250 to 1000mg Lminus1was applied in weight loss and electrochemical assays in acidmedia forASTM1020 carbon steelThese assays showed somerelevant inhibition efficiency (gt 90) for named inhibitors 1and 2 From Langmuir isotherm the adsorption of inhibitorson the carbon steel surface might occur by physical andchemical interaction however the activation energy raised

suggesting a physisorption process for the interaction of theinhibitor on the carbon steel surface

For the future our perspective is the addition of anamount of these inhibitors in commercial anticorrosive inks

Data Availability

The data used to support the findings of this study areavailable from the corresponding author upon request

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Theauthors thankNational Council of Technological and Sci-entific Development (Brazil) for research fellowship supportand IFRJ and FAPERJ for the financial support

References

[1] J A Joule and K Mills Heterocyclic Chemistry Wiley 5thedition 2010

[2] C G de Oliveira VW Faria G F de Andrade et al ldquoSynthesisof thiourea derivatives and its evaluation as corrosion inhibitorfor carbon steelrdquo Phosphorus Sulfur and Silicon and the RelatedElements vol 190 no 8 pp 1366ndash1377 2015

[3] A Zarrouk B Hammouti S S Al-Deyab et al ldquoCorrosioninhibition performance of 35-Diamino-124-triazole for Pro-tection of Copper inNitric Acid Solutionrdquo International Journalof Electrochemistry vol 7 pp 5997ndash6011 2012

[4] FM Al-Kharafi F H Al-Hajjar andA Katrib ldquo3-phenyl-124-triazol-5-one as a corrosion inhibitor for copperrdquo CorrosionScience vol 26 pp 257ndash264 1986

[5] P G Fox and P A Bradley ldquo1 2 4-triazole as a corrosioninhibitor for copperrdquo Corrosion Science vol 20 pp 643ndash6491980

[6] K R Ansari D K Yadav E E Ebenso and M A QuraishildquoCorrosion inhibition and adsorption studies of somebarbi-turates on mild steelacid interfacerdquo International Journal ofElectrochemical vol 7 pp 4780ndash4799 2012


[7] MAQuraishi Sudheer K R Ebenso andE E Ebenso ldquo3-Arylsubstituted triazole derivatives as new and effective corrosioninhibitors for mild steel in hydrochloric acid solutionrdquo Interna-tional Journal of Electrochemcal Science vol 7 pp 7476ndash74922012

[8] H-L Wang H-B Fan and J-S Zheng ldquoCorrosion inhibitionof mild steel in hydrochloric acid solution by a mercapto-triazole compoundrdquo Materials Chemistry and Physics vol 77no 3 pp 655ndash661 2003

[9] L Lin Wang M J Zhu F C Yang and C W Gao ldquoStudyof a triazole derivative as corrosion inhibitor for mild steel inphosphoric acid solutionrdquo International Journal of Corrosionvol 2012 Article ID 573964 6 pages 2012

[10] G E Negron-Silva R Gonzalez-Olvera D Angeles-Beltranet al ldquoSynthesis of new 123-triazole derivatives of uraciland thymine with potential inhibitory activity against acidiccorrosion of steelsrdquoMolecules vol 18 no 4 pp 4613ndash4627 2013

[11] L M Alaoui B Hammouti A Bellaouchou A Benbachir AGuenbour and S Kertit ldquoCorrosion inhibition and adsorptionproperties of 3-amino-123-triazole on mild steel in H3PO4rdquoDer Pharma Chemica vol 3 no 4 pp 353ndash360 2011

[12] N Boechat V F Ferreira S B Ferreira et al ldquoNovel 123-triazole derivatives for use against mycobacterium tuberculosisH37Rv (ATCC 27294) strainrdquo Journal of Medicinal Chemistryvol 54 no 17 pp 5988ndash5999 2011

[13] S Zeghada G Bentabed-Ababsa A Derdour et al ldquoA com-bined experimental and theoretical study of the thermalcycloaddition of aryl azides with activated alkenesrdquo Organic ampBiomolecular Chemistry vol 9 no 11 pp 4295ndash4305 2011

[14] S Ram and R E Ehrenkaufer ldquoAmmonium formate in organicsynthesis a versatile agent in catalytic hydrogen transfer reduc-tionsrdquo Synthesis vol 1988 no 2 pp 91ndash95 1988

[15] S E Yoo and S H Lee ldquoReduction of organic compounds withsodium borohydride-copper(II) sulfate systemrdquo Synlett no 7pp 419-420 1990

[16] S Jothilakshmi and K U Rekha Rekha ldquoA review of greencorrosion inhibitors from plant extracts of various metal indifferent mediumrdquo Advances in Materials and Corrosion vol 3pp 17ndash19 2014

[17] V GentilCorrosao 2011 6119886 (LTC) Rio de Janeiro Brazil 2001[18] K Tebbji A Aouniti A Attayibat et al ldquoInhibition efficiency

of two bipyrazole derivatives on steel corrosion in hydrochloricacid mediardquo Indian Journal of Chemical Technology vol 18 no3 pp 244ndash253 2011

[19] P P Kumari P Shetty and S A Rao ldquoElectrochemical mea-surements for the corrosion inhibition of mild steel in 1 Mhydrochloric acid by using an aromatic hydrazide derivativerdquoArabian Journal of Chemistry vol 10 pp 653ndash663 2017

[20] G M Pinto J Nayak and A N Shetty ldquo4-(NN-Diethyl-amino)benzaldehyde thiosemicarbazone as Corrosion Inhib-itor for 6061 Al ndash 15 vol pct SiC(p) Composite and its Basealloyrdquo Materials Chemistry and Physics vol 125 pp 628ndash6402011

[21] F S De Souza and A dan Spinelli ldquoCaffeic acid as a greencorrosion inhibitor for mild steelrdquoCorrosion Science vol 51 no3 pp 642ndash649 2009

[22] A Ostovari S M Hoseinieh M Peikari S R Shadizadehand S J Hashemi ldquoCorrosion inhibition of mild steel in 1M HCl solution by henna extract a comparative study of theinhibition by henna and its constituents (Lawsone Gallic acid120572-d-Glucose and Tannic acid)rdquo Corrosion Science vol 51 no 9pp 1935ndash1949 2009

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018


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Journal of

Chemistry


Advances inPhysical Chemistry

Hindawiwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2018

Bioinorganic Chemistry and ApplicationsHindawiwwwhindawicom Volume 2018

SpectroscopyInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Medicinal ChemistryInternational Journal of


NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Applied ChemistryJournal of



Biochemistry Research International


Enzyme Research


Journal of

SpectroscopyAnalytical ChemistryInternational Journal of


MaterialsJournal of



BioMed Research International Electrochemistry

International Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom


NH2

N

N

N

HO

1

NH2

N

N

N

HO

2

NH2

N

N

N

EtO

O

3

Figure 1 123-Triazole derivatives structures

All reagents and solvents used were commercially avail-able and were employed without further purification unlessspecifically indicated

21 Inhibitor Synthesis

Synthesis of 1-azido-4-nitrobenzene (5) In a flask previouslycontaining HCl 6N (30mL) p-nitroaniline (3 g 2174mmol)was added with magnetic stirring at room temperatureAfterwards a solution of NaNO2 (15 g 2174mmol) in 20mLof water was added dropwise controlling the temperature at5-10∘C The reaction was stirred for 1 h at room temperatureand a solution of NaN3 (141 g 2174mmol) in 20mL of waterwas added slowly under vigorous stirring The reaction wasfollowed by thin layer chromatography (TLC) and productwas filtered washed with water and dried The product wasobtained as a yellowish solid yield 90 (32 g)

FT ATR IR 3069 (C-H ar st) 2120 (N3 st) 1590 (ar C=Cst) 1512 (C-NO2 ass st) 1287 (C-NO2 sym st)

Synthesis of (1-(4-nitrophenyl)-1H-123-triazol-4-yl)methanol(7) To a suspension of (5) (12 g 732mmol) in terc-butanol(5mL) was added a mixture of ascorbic acid (281mg16mmol) CuSO45H2O (145mg 058mmol) and NaHCO3(135mg 16mmol) in 55mL of water Afterwards propar-gylic alcohol (052mL 9mmol) was added and the reactionmixture was stirred for 24-48 h at room temperature Thereaction was followed by TLC and the product was obtainedby filtration washed with water and dried The product wasobtained as a brownish solid and was used without furtherpurification in next step yield 78 (125 g)

FT-IR (ATR) 3436 (O-H st) 1598 (ar C=C st) 1510 (C-NO2 ass st) 1287 (C-NO2 sym st)

Synthesis of (1-(4-aminophenyl)-1H-123-triazol-4-yl)methanol(1) To a suspension of (7) (154 g 70mmol) in water(40mL)NH4Cl (750mg 14mmol) and zinc powder (3325g508mmol) were addedThe reaction mixture was stirred and

heated to 80∘C during 3 hours The resulting mixture was fil-tered and washed with dichloromethane The aqueous phasewas extracted with dichloromethane five times The organicphase was dried over Na2SO4 filtered and concentrated toobtain the product as a pinkish solid yield of 68 (090 g)

FT-IR (ATR) 3462 (O-H st) 3362 (N-H st) 1631 (ar C=Cst) 860 (ar C-H 120575)1H NMR (500MHz DMSO-1198896) 120575 828 (s 1H) 745-743

(d J=90Hz 2H) 671-669 (d J=85Hz 2H) 532 (s 2H)505 (s 1H) 458 (s 2H)13CNMR (225MHz DMSO-1198896) 120575 14922 14848 12626

12154 12062 11393 5506

Synthesis of ethyl 1-(4-nitrophenyl)-5-methyl-1H-123-triazole-4-carboxylate (6) To a round bottom flask of 50mL wereadded 276mg (2mmol) of compound 5 and 1mL of DMF andthe solid was solubilized with magnetic stirrer at room tem-perature Afterwards 06mL of trimethylamine and 055mLof ethyl acetoacetate were added to the flask The reactionmixture was stirred at room temperature for 24 hours Thereaction was followed by thin layer chromatography Thework up of the product was made through filtration Thereaction had a yield of 94 (436mg) brownish solid

FT ATR IR 3080 (C-H ar st) 2976 (C-H aliph st) 1711(C=O st) 1530 (C-NO2 assym st) 1343 (C-NO2 sym st) 852(ar C-H 120575)Synthesis of ethyl 1-(4-aminophenyl)-5-methyl-1H-123-tria-zole-4-carboxylate (3) In a round bottom flask of 100mLwere added 332mg (13mmol) of compound 6 50mg ofpalladium 10 supported on active charcoal 10 375mg ofammonium formate and 2mL of methanol The reactionwas maintained under nitrogen atmosphere with magneticstirring and room temperature for 24 hoursThe reaction wasfollowed by thin layer chromatography The reaction mixturewas filtered through Celite and the Celite was washed with10mL of dichloromethane The filtrate was extracted withbrine the organic phase was dried with Na2SO4 anhydrous





13593 12675 12390 11423 6067 1460 1004





12640 11425 6212 2352 902




119864119868 () = 1198820 minus1198821198820 times 100 (1)


119882 = 119870119872119860119905 120588 (2)







NO2

NH2

a)

NO2

N3

b)

NO2

c)

N

N

N

NH2

N

N

N

EtOEtO

O O

NO2

N

N

N

O

g)e)

NH2

N

N

N

OH

NO2

N

N

N

HO

d) f)

NH2

N

N

N

HO

4 5 6 3

12

7 8



119868119864 () = 1198951198881199001199031199030 minus 1198951198881199001199031199031198951198881199001199031199030 times 100 (3)


119868119864 () = 119877119888119905 minus 1198771198881199050119877119888119905 times 100 (4)


























(mmy) (mmy) () () (mmy) () ()4 160 17 892 15 03 979 068 147 18 875 19 03 979 0212 147 16 888 07 02 987 0524 128 09 934 03 04 967 0348 142 16 886 12 03 979 02




119886119889119904(KJ molndash1)

1 1027 09999 925 ndash3362 0998 09991 1136 ndash331

80

0

60

50

40

30

20

10

000605040302010

C (m

mol

L-

)

C (mmol L-)




119862120579 = 119862 + 1

119870 (5)



119870 = 15555 exp(

minus1198660119886119889119904119877119879 ) (6)










1198660119886119889119904





ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)




ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)



119864119886 minus 119867 = 119877119879 (9)




Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls








13593 12675 12390 11423 6067 1460 1004





12640 11425 6212 2352 902




119864119868 () = 1198820 minus1198821198820 times 100 (1)


119882 = 119870119872119860119905 120588 (2)







NO2

NH2

a)

NO2

N3

b)

NO2

c)

N

N

N

NH2

N

N

N

EtOEtO

O O

NO2

N

N

N

O

g)e)

NH2

N

N

N

OH

NO2

N

N

N

HO

d) f)

NH2

N

N

N

HO

4 5 6 3

12

7 8



119868119864 () = 1198951198881199001199031199030 minus 1198951198881199001199031199031198951198881199001199031199030 times 100 (3)


119868119864 () = 119877119888119905 minus 1198771198881199050119877119888119905 times 100 (4)


























(mmy) (mmy) () () (mmy) () ()4 160 17 892 15 03 979 068 147 18 875 19 03 979 0212 147 16 888 07 02 987 0524 128 09 934 03 04 967 0348 142 16 886 12 03 979 02




119886119889119904(KJ molndash1)

1 1027 09999 925 ndash3362 0998 09991 1136 ndash331

80

0

60

50

40

30

20

10

000605040302010

C (m

mol

L-

)

C (mmol L-)




119862120579 = 119862 + 1

119870 (5)



119870 = 15555 exp(

minus1198660119886119889119904119877119879 ) (6)










1198660119886119889119904





ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)




ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)



119864119886 minus 119867 = 119877119879 (9)




Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





NO2

NH2

a)

NO2

N3

b)

NO2

c)

N

N

N

NH2

N

N

N

EtOEtO

O O

NO2

N

N

N

O

g)e)

NH2

N

N

N

OH

NO2

N

N

N

HO

d) f)

NH2

N

N

N

HO

4 5 6 3

12

7 8



119868119864 () = 1198951198881199001199031199030 minus 1198951198881199001199031199031198951198881199001199031199030 times 100 (3)


119868119864 () = 119877119888119905 minus 1198771198881199050119877119888119905 times 100 (4)


























(mmy) (mmy) () () (mmy) () ()4 160 17 892 15 03 979 068 147 18 875 19 03 979 0212 147 16 888 07 02 987 0524 128 09 934 03 04 967 0348 142 16 886 12 03 979 02




119886119889119904(KJ molndash1)

1 1027 09999 925 ndash3362 0998 09991 1136 ndash331

80

0

60

50

40

30

20

10

000605040302010

C (m

mol

L-

)

C (mmol L-)




119862120579 = 119862 + 1

119870 (5)



119870 = 15555 exp(

minus1198660119886119889119904119877119879 ) (6)










1198660119886119889119904





ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)




ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)



119864119886 minus 119867 = 119877119879 (9)




Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls


























(mmy) (mmy) () () (mmy) () ()4 160 17 892 15 03 979 068 147 18 875 19 03 979 0212 147 16 888 07 02 987 0524 128 09 934 03 04 967 0348 142 16 886 12 03 979 02




119886119889119904(KJ molndash1)

1 1027 09999 925 ndash3362 0998 09991 1136 ndash331

80

0

60

50

40

30

20

10

000605040302010

C (m

mol

L-

)

C (mmol L-)




119862120579 = 119862 + 1

119870 (5)



119870 = 15555 exp(

minus1198660119886119889119904119877119879 ) (6)










1198660119886119889119904





ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)




ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)



119864119886 minus 119867 = 119877119879 (9)




Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls











1198660119886119889119904





ln119882119888119900119903119903 = minus119864119886119877119879 + ln119860 (7)




ln119882119888119900119903119903119879 = ln119877

119873ℎ + 1198780119877 minus 1198670

119877119879 (8)



119864119886 minus 119867 = 119877119879 (9)




Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls






Inhibitor 119864119886 1199032

Δ119867 Δ1198781199032

119864119886minus Δ119867


minus20

minus40

minus60

minus80

minus100



34times10-3


Blank

ln W

corr

--1

) (g

cmh

1T ( C)∘


minus80

minus100

minus120

minus140

1T ( C)



34times10-3

∘


Blank

ln W

Tco

rr-

-1-1

) (g

cmh

C∘








10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)

Blank250 mg

-1500 mg

-1

750 mg -1

1000 mg -1


E (mV) vs SCE

(a)

10-1

10-2

10-3

10-4

10-5

10-6

10-7

log

i (A

cm-

)


E (mV) vs SCE

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)





Blank ndash4964 06055 18018 10174

1


2






Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





Blank

30

25

20

15

10

5

0302520151050

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

(a)-I

mag

inar

y Pa

rt (

cm-

)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

(b)

Blank250 mg

-1

500 mg -1

750 mg -1

1000 mg -1

-Im

agin

ary

Part

(cm

-)

Real Part ( cm-)

800

700

600

500

400

300

200

100

08007006005004003002001000

(c)








119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







119877119888119905

119877119904

119891119898119886119909

119862119889119897



1


2




119862119889119897 = 12120587119891119898119886119909119877119888119905 (10)




4 Conclusions




Data Availability




Acknowledgments


References





























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls


























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




Synthesis of 1,2,3-Triazole Derivatives and Its Evaluation...

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Transcript of Synthesis of 1,2,3-Triazole Derivatives and Its Evaluation...