Research Article Kinetic Study of Catalytic Esterification

Hindawi Publishing CorporationISRN Chemical EngineeringVolume 2013 Article ID 520293 6 pageshttpdxdoiorg1011552013520293

Research ArticleKinetic Study of Catalytic Esterification of Butyric Acidand Ethanol over Amberlyst 15

Nisha Singh1 Raj kumar2 and Pravin Kumar Sachan3

1 Department of Chemical Engineering RNCET Panipat Haryana 132103 India2Department of Chemical Engineering Bipin Tripathi Kumaon Institute of Technology Dwarahat AlmoraUttarakhand 263653 India

3 Department of Biochemical Engineering Bipin Tripathi Kumaon Institute of Technology Dwarahat AlmoraUttarakhand 263653 India

Correspondence should be addressed to Raj kumar ranvir523gmailcom

Received 29 June 2013 Accepted 5 August 2013

Academic Editors G Bayramoglu and R Mariscal

Copyright copy 2013 Nisha Singh 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

The esterification reaction of butyric acid with ethanol has been studied in the presence of ion exchange resin (Amberlyst 15)Ethyl butyrate was obtained as the only product which is used in flavours and fragrances Industrially speaking it is also oneof the cheapest chemicals which only adds to its popularity The influences of certain parameters such as temperature catalystloading initial concentration of acid and alcohols initial concentration of water and molar ratio were studied Conversions werefound to increase with an increase in both molar ratio and temperature The experiments were carried out in a batch reactorin the temperature range of 32815ndash34815 K Variation of parameters on rate of reaction demonstrated that the reaction wasintrinsically controlled Experiment kinetic data were correlated by using pseudo-homogeneous model The activation energy forthe esterification of butyric acid with ethanol is found to be 30 k Jmol

1 Introduction

Organic esters are important fine chemicals used widely inthe manufacturing of flavors pharmaceuticals plasticizersand polymerization monomers They are also used as emul-sifiers in the food and cosmetic industries Several syntheticroutes are available for obtaining organic esters most ofwhich have been briefly reviewed by Yeramian et al [1]Several synthetic routes have been used tomake organic esterbut the most-used methodology for ester synthesis is directesterification of carboxylic acids with alcohols in the presenceof acidbase catalysts Esterification is usedThemost accept-able method is to react the acid with an alcohol catalyzed bymineral acids and the reaction is reversible [2] Esterificationof carboxylic acid with alcohol in the presence of acidcatalyst has been the subject of investigation ofmany researchworkers [3] The traditional industrial process of synthesiz-ing esters using homogeneous acid catalyst is convenientlyreplaced by solid acid catalyst ion exchange resins clay andso forth [4] The ion exchange resin is a promising material

for replacement of homogeneous acid catalystsThe use of ionexchange resins as solid catalyst has many advantages overhomogeneous acid catalysts They eliminate the corrosiveenvironment they can separate from liquid reaction mixtureby filtration and have high selectivity [5] They can alsobe used repeatedly over a prolonged period without anydifficulty in handling and storing them And the purityof the products is higher since the side reactions can becompletely eliminated [6] Fatty acid esters are used as rawmaterials for emulsifiers oiling agents for foods spin finishand textiles lubricants for plastics paint and ink additivesand for mechanical processing personal care emollients andsurfactants and base materials for perfumes They are usedas solvents cosolvents and oil carriers in the agriculturalindustries [7] The esters of biobased organic acids fall intothe category of benign or green solvents and are promisingreplacements for halogenated petroleum-based solvent in awide range of applications [8]

The ester of butyric acid and ethanol namely ethylbutyrate finds wide applications It is commonly used as

2 ISRN Chemical Engineering

artificial flavoring such as pineapple flavoring in alcoholicbeverage as a solvent in perfumery products and as aplasticizer for cellulose Ethyl butyrate is one of the mostcommon chemicals used in flavors and fragrances It can beused in a variety of flavors orange (most common) cherrypineapple mango guava bubblegum peach apricot fig andplum Industrially speaking it is also one of the cheapestchemicals which only adds to its popularity Although to thebest of our knowledge no researcher has reported the kineticsof esterification of butyric with ethanol in the presence ofAmberlyst 15 there are a number of studies related to theother esterification reactions catalyzed by solid resins

2 Experimental

21 Chemicals Ethanol ofgt985purity (Merck) and butyricacid of 998 purity (Merck) are used as the reactantsThe reaction occurred in the solution of dioxane of 990purity (Merck) All the aqueous solutions used in the analysisare prepared with distilled water sodium hydroxide (SDFine Chemicals Ltd Boisar India) and phenolphthaleinindicator (Qualigens Fine Chemicals Mumbai India)

22 Catalyst Amberlyst 15 (Rohm and Hass) is used ascatalyst It is synthesized from styrene-divinylbenzene bysuspension polymerization and finally sulfonated by sulfuricacid The esterification reaction of butyric acid with ethanolwas studied using different catalysts The catalytic activity ofAmberlyst 15 is higher than the Amberlyst 35 It is due toAmberlyst 15 has higher surface area and pore volume thanAmberlyst 35 So Amberlyst 15 is found to be the best catalystto generate the data

3 Apparatus and Procedure

Esterification reaction of butyric acid with ethanol withthe initial concentrations of 144molL and 1484molLrespectively was carried out in three-necked flask of 500mLcapacity fitted with a reflux condenser a thermometer and amagnetic stirrer The initial volume of reaction mixture wasapproximately 150mL A reflux condenser is used to avoid theloss of volatile compounds The ion exchange resin suspendsin the reaction mixture with the help of stirrer Temperatureinside the reactor is controlled within the accuracy of plusmn05 KIn all the experiments a known amount of butyric acid andthe catalyst charged into the reactor and heated to the desiredtemperature All of the reactants charged in the reactor arevolumetrically measuredThis time is considered the startingpoint of the reaction Samples were withdrawn at a regulartime intervals for analysis The progress of the reaction wasfollowed by withdrawing small enough samples to considerthem negligible compared to the volume of the reactionmixture at regular intervals

4 Analysis

All samples were measured in measuring cylinder of 1mLtaken periodically and titrated against 1 N standard NaOHsolution using phenolphthalein as an indicator

0

0001

0002

0003

0004

0005

0006

0007

0 05 1 15 2CA0 (molL)

minusr A

0(m

olLmiddotm

in)

Figure 1 Effect of acid concentration on initial reaction rate (1198621198610=

1484molL)

5 Kinetic Modeling

A pseudo-homogeneous model cab was effectively applied tocorrelate the kinetic data of the liquid solid catalytic reactionThe esterification reactions are known to be reversible reac-tion of second orderThe general rate expression can be givenby

119860 + 119861 997888rarr 119864 +119882 (1)

where 119860 = butyric acid 119861 = ethanol 119864 = ethyl butyrate and119882 = water and

minus119903119860=

119870119891 (119898119881) (119862119860119862119861 minus (119862119864 (119862119882119870119890)))

1 + 119870119861119862119861+ 119870119882119862119882

(2)

where subscript 119862119860and 119862

119861refer to acid and alcohol concen-

trations respectively 119870119891is forward reaction rate constant

119870119890is the equilibrium constant of the reaction 119870 is the

adsorption equilibrium constants 119898 is the quality of dryresin and 119881 is the volume of the resin

For the initial reaction rate with no product present (2)can be reduced to

minus1199031198600

= (

1198701198911198981198621198610119881

1 + 1198701198611198621198610

)1198621198600 (3)

A plot of minus1199031198600

versus 1198621198600

provides a straight line with slopeof (1198701198911198981198621198610119881(1 + 119870

1198611198621198610)) These lines were presented in

Figure 1 at temperature 348KIf (3) is rearranged for variables 119862

1198610values the following

expression can be obtained

11986211986001198621198610

minus1199031198600

=

119881

119870119891119898

+ (

119881119870119861

119870119891119898

)1198621198610 (4)

A plot of 11986211986001198621198610(minus1199031198600) versus 119862

1198610produces a straight line

with the slope of 119881119870119861119870119891119898 and intersection of 119881119870

119891119898

These lines are presented in Figure 1 at 348K From the slopeand lines shown in Figure 2 the following equation can beheld

ISRN Chemical Engineering 3

3195

3200

3205

3210

3215

3220

3225

3230

13 135 14 145 15CB0 (molL)

minusr A

0(m

ol m

inL

)CA0lowastCB0

Figure 2 11986211986001198621198610minus1199031198600

versus 1198621198610 temperature = 348K catalyst

loading = 732 kgm3

In order to evaluate the inhibiting effect of water concen-tration (2) with no ester present initially can be written as

minus1199031198600

=

119870119891 (119898119881)11986211986001198621198610

1 + 1198701198611198621198610+ 1198701198821198621198820

(5)

from which the following equation can be obtained

11986211986001198621198610

minus1199031198600

=

119881 (1 + 1198701198611198621198610)

119870119891119898

+ (

119881119870119882

119870119891119898

)1198621198820 (6)


1198820at constant acid and

alcohol concentrations gives a straight line with slope of119881119870119882119870119891119898 and intersection of 119881(1 + 119870

1198611198621198610)119870119891119898 These

lines were presented in Figure 3At temperature 348K

1198701198911198981198621198610

119881 (1 + 1198701198611198621198610)

= 00045

119881

119870119891119898

= 301206

119881119870119861

119870119891119898

= 1440

119881 (1 + 1198701198611198621198610)

119870119891119898

= 320113

119881119870119882

119896119891119898

= 2218

(7)

Solving these equations by the ldquomethod of averagesrdquo wefound the values of

119870119891= 453 times 10

minus6 L2mol

119870119861= 478 times 10

minus6 Lmol119870119882= 735 times 10

minus6 Lmol

51 Integrated Rate Expression If the reaction rate given in(3) is expressed in terms of conversion of butyric acid thefollowing equation can be obtained Adsorption effect ofalcohol and water is neglected as discussed earlier and asalcohol is taken in far excess so 119862

1198610is taken as constant

hence (3) becomes a pseudo-first-order rate equation

minus1199031198600

= 119870119891

119908

119881

1198621198610119862119860 (8)

0004

00041

00042

00043

00044

00045

00046

00047

0 05 1 15

minusr A

0(m

olLmiddoth

)

CW0 (molL)

Figure 3 Effect of water concentration on initial reaction ratecatalyst loading = 732 kgm3 temperature = 348K

Putting 119862119860= 1198621198600(1 minus 119883

119860)

minus1198621198600

119889119909119860

119889119905

= 119870119891

119908

119881

11986211986101198621198600(1 minus 119883

119860)

minus

119889119909119860

119889119905

= 119870119891

119908

119881

1198621198610(1 minus 119883

119860)

int

119909119860

0

minus

119889119883119860

(1 minus 119883119860)

= int119870119891

119908

119881

1198621198610119889119905

minus ln (1 minus 119883119860) = 119870

119891

119908

119881

1198621198610119905

(9)

where 119883119860is the fractional conversion of 119860 Thus a plot

of minus ln(1 minus 119883119860) against time 119905 gives a slope which represents

119870

6 Results and Discussion

The esterification reaction of butyric acid with ethanol wasstudied in a batch reactor in the presence of acidic ionexchange resin catalyst Amberlyst 15The kinetics of esterifi-cation of butyric acid is studied at different temperatures from32815 to 34815 K with different molar ratios and varyingcatalyst loading (Figure 11) A pseudo-homogeneous modelhas been used to describe the esterification reaction catalyzedby Amberlyst 15 The effects of temperature catalyst loadingand molar ratio are studied

61 Catalyst Performance In Figure 5 a comparison of thebehavior of the Amberlyst 15 and Amberlyst 35 catalystsis shown Catalysts are used to access their efficacy in theesterification of butyric acid with ethanol Amberlyst 15 isshown to be an effective catalyst as compared to Amberlyst35 The catalytic activity of Amberlyst 15 has higher activitythan Amberlyst 35 It is due to Amberlyst 15 has highertotal exchange capacity surface area and pore volume thanAmberlyst 35 So Amberlyst 15 is found to be the best catalystto generate the data (Table 1)

62 Effect of Catalyst Loading In Figure 6 experiments workconducted by varying the catalyst loading from 244 kgm3


Table 1 Characteristics of the catalysts

Property Amberlyst 35 Amberlyst 15Acidity (eq H+ kgminus1) 532 475Surface area (m2 gminus1) 34 42Total exchange capacity (eqkg) 520 470Pore volume (cm3 gminus1) 028 036Mean pore diameter (A) 329 343Skeletal density (g cmminus3) 1542 1416

3195

3200

3205

3210

3215

3220

3225

3230

0 05 1 15

CA0lowastCB0minusr A

0(m

olmiddotm

inL

)

CW0 (molL)

Figure 4 (11986211986001198621198610minus1199031198600) versus 119862

1198820 temperature = 348K catalyst

loading = 732 kgm3

to 814 kgm3 Keeping butyric acid and ethanol molar ratio1 10 and and the reaction temperature 75∘C It is found thatwith increase in catalyst loading the conversion of butyricacid increased with the proportional increase in the activesites At higher catalyst loading the rate of mass transfer ishigh and therefore there is no significant increase in the rate[9]

This data is once again used to plot minus ln(1 minus 119883119860) versus 119905

in Figure 7 and get a straight line passing through origin theslope of which gives the value of 119870

The values of 119870 are plotted against catalyst loading 119908(kgm3) in Figure 8 and it is observed that with the increasein 119908 there is a linear increase in 119870 thus it validates themodel

63 Effect of Molar Ratio The concentration of ethanol hadan influence on the reaction rate and on the conversion Theresults are given in Figure 9 It can be seen that the conversionof acid increases with increasing the initial molar ratio ofethanol to butyric acid For the esterification with ethanolthe equilibrium conversion of butyric acid increases from31 to 81 on varying ethanol to butyric acid ratio from 1 1to 1 15 for catalyst loading 732 kgm3 at temperature 348K(Figure 4) The result observed for the effect of initial molarratio of ethanol to butyric acid indicated that the equilibriumconversion of butyric acid can be effectively enhanced byusing a large excess of ethanol

For calculating 119870 these data are once again used to plotminus ln(1 minus 119883

119860) versus 119905 to get a straight line passing through

origin shown in Figure 10 the slope of which gives the valueof119870

0

10

20

30

40

50

60

70

80

0 200 400

Frac

tiona

l con

vers

ion

Time (min)

Figure 5 Variation with type of catalyst Amberlyst 15 (⧫) andAmberlyst 35 (◼) catalyst loading = 488 kgm3 temperature = 75∘Cand molar ratio = 1 10 (butyric acid ethanol)

0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)

Figure 6 Comparison of the effect of catalyst loading (⧫)244 kgm3 (◼) 325 kgm3 (998771) 488 kgm3 (times) 569 kgm3 (∙)6506 kgm3 (+) 732 kgm3 and (minus) 814 kgm3 on the conversion ofbutyric acid with ethanol molar ratio = 1 10 (butyric acid ethanol)and temperature = 75∘C

The values of 119870 are plotted against catalyst loading 119908(kgm3) and it was observed that with the increase in119908 therewas a linear increase in 119870 thus it validates the model

64 Effect of Temperature The study of the effect of temper-ature is very important because this information is useful incalculating the activation energy In order to investigate theeffect of temperature esterification reactions are carried outin the temperature region from 328 to 348K while keepingthe acid alcohol ratio at 1 10 and the catalyst loading of732 kgm3 dry resin (Figure 13) With an increase in reactiontemperature the initial reaction rate or the conversion ofthe butyric acid is found to increase substantially as shownin Figure 12 It shows that the higher temperature yieldsthe greater conversion of the acid at fixed contact time


0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)

Figure 7 Typical kinetic plot of comparison of different cata-lyst loadings (⧫) 244 kgm3 (◼) 325 kgm3 (998771) 488 kgm3 (times)569 kgm3 (lowast) 6506 kgm3 (∙) 732 kgm3 and (minus) 814 kgm3

0

005

01

015

02

025

03

035

04

0 20 40 60 80 100Catalyst loading (kgm3)

Rate

cons

tantK

(minminus1)

Figure 8 Effect on119870 with catalyst loading

0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)

Figure 9 Comparison of the effect of molar ratio 1 1 (⧫) 1 5 (◼)1 10 (998771) and 1 15 (times) on the conversion of butyric acidwith ethanolwith catalyst loading of 732 kgm3 and temperature of 75∘C

0

02

04

06

08

1

12

14

16

18

2

0 100 200 300 400Time (min)

minus(ln(1minusXA))

Figure 10 Typical kinetic plot of comparison of different molarratios (⧫) 1 5 (◼) 1 10 and (998771) 1 15 temperature 34815 K andcatalyst loading 732 (kgm3)

0

0001

0002

0003

0004

0005

0006

0 5 10 15 20Molar ratio

Rate

cons

tantK

(hrminus1)

Figure 11 Effect of different molar ratios rate constant (119870)versus molar ratio temperature 34815 K and catalyst loading 732(kgm3)

0010203040506070809

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)

Figure 12 Comparison of the effect of temperature 328K (⧫) 333 K(◼) 338 K (998771) 343 K (times) and 348K (lowast) on the conversion of butyricacidwith ethanol with catalyst loading of 732 kgm3 andmolar ratioof 1 10 (butyric acid ethanol)


0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)

Figure 13 Typical kinetic plot of comparison of different tempera-tures 328K (⧫) 333 K (◼) 338 K (998771) 343K (times) and 348K (lowast)

53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)

Figure 14 Arrhenius plot of minus ln 119870 versus 1119879 (molar ratio = 1 10catalyst loading = 732 kgm3)

Thus 75∘C is chosen as the maximum working temperaturefor the butyric acid esterification

Arrhenius law expresses the temperature dependency ofthe rate constant

119870 = 1198960exp(minus

1198640

119877119879

) (10)

where 1198960= frequency factor 119864

0= activation energy and 119877 =

gas constantThis data is once again used to plotminus ln(1minus119883

119860) versus 119905 to

get a straight line passing through origin the slope of whichgives the value of119870

Equation (1) a plot of minus ln 119870 versus 1119879 at constant acidand alcohol concentrations gives a straight line with a slopeof (119864119886119877) as shown in Figure 14

The study on the effect of temperature is very importantfor heterogeneously catalyzed reaction as this information isuseful in calculating the activation energy for this reactionAn Arrhenius plot for the initial rate of reaction is given inFigure 14The activation energy for the esterification reactionbased on the initial rate is found to be 30KJmol

7 Conclusion

The kinetics of esterification of butyric acid with ethanol inthe temperature ranging between 32815 K and 34815 K andat molar ratio 1 5 to 1 15 is investigated experimentally ina stirred batch reactor using Amberlyst 15 The optimumconditions for synthesizing ethyl butyrate have been delin-eated It has also been observed that the initial reaction rateincreases linearly with acid and alcohol concentrations Andrate of reaction is found to increase with the increase incatalyst loading temperature and molar ratio Eley-Ridealmodel is applied to study the kinetics of the reaction Asa result it is concluded that the acidic resin Amberlyst 15is a suitable catalyst for this reaction since in the presenceof it the reaction has been found to take place between anadsorbed alcohol molecule and a molecule of acid in thebulk phase (Eley-Rideal model) It is also observed that waterhas inhibiting effect of reaction Temperature dependencyof the kinetic constants has been found to apply Arrheniusequation The activation energy is found to be 30KJmol

References

[1] A A Yeramian J C Gottifredi and R E CunninghamldquoVapor-phase reactions catalyzed by ion exchange resins IIIsopropanol-acetic acid esterificationrdquo Journal of Catalysis vol12 no 3 pp 257ndash262 1968

[2] A Izci and F Bodur ldquoLiquid-phase esterification of acetic acidwith isobutanol catalyzed by ion-exchange resinsrdquo Reactive andFunctional Polymers vol 67 no 12 pp 1458ndash1464 2007

[3] M R Altiokka and A Citak ldquoKinetics study of esterification ofacetic acidwith isobutanol in the presence of amberlite catalystrdquoApplied Catalysis A vol 239 no 1-2 pp 141ndash148 2003

[4] K R Ayyappan T A Pal G Ritu B Ajay and R K WanchooldquoCatalytic hydrolysis of ethyl acetate using cation exchange resin(Amberlyst-15) a kinetic studyrdquo Bulletin of Chemical ReactionEngineering amp Catalysis vol 4 no 1 pp 16ndash22 2009

[5] B Chemseddine and R Audinos ldquoUse of ion-exchange mem-branes in a reactor for esterification of oleic acid and methanolat room temperaturerdquo Journal of Membrane Science vol 115 no1 pp 77ndash84 1996

[6] B Saha and M M Sharma ldquoEsterification of formic acidacrylic acid andmethacrylic acid with cyclohexene in batch anddistillation column reactors ion-exchange resins as catalystsrdquoReactive and Functional Polymers vol 28 no 3 pp 263ndash2781996

[7] A Chakrabarti and M M Sharma ldquoEsterification of aceticacid with styrene ion exchange resins as catalystsrdquo ReactivePolymers vol 16 no 1 pp 51ndash59 1991

[8] C F Oliveira L M Dezaneti F A C Garcia et al ldquoEsterifi-cation of oleic acid with ethanol by 12-tungstophosphoric acidsupported on zirconiardquo Applied Catalysis A vol 372 no 2 pp153ndash161 2010

[9] S S Dash and K M Parida ldquoEsterification of acetic acid withn-butanol over manganese nodule leached residuerdquo Journal ofMolecular Catalysis A vol 266 no 1-2 pp 88ndash92 2007

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artificial flavoring such as pineapple flavoring in alcoholicbeverage as a solvent in perfumery products and as aplasticizer for cellulose Ethyl butyrate is one of the mostcommon chemicals used in flavors and fragrances It can beused in a variety of flavors orange (most common) cherrypineapple mango guava bubblegum peach apricot fig andplum Industrially speaking it is also one of the cheapestchemicals which only adds to its popularity Although to thebest of our knowledge no researcher has reported the kineticsof esterification of butyric with ethanol in the presence ofAmberlyst 15 there are a number of studies related to theother esterification reactions catalyzed by solid resins

2 Experimental

21 Chemicals Ethanol ofgt985purity (Merck) and butyricacid of 998 purity (Merck) are used as the reactantsThe reaction occurred in the solution of dioxane of 990purity (Merck) All the aqueous solutions used in the analysisare prepared with distilled water sodium hydroxide (SDFine Chemicals Ltd Boisar India) and phenolphthaleinindicator (Qualigens Fine Chemicals Mumbai India)

22 Catalyst Amberlyst 15 (Rohm and Hass) is used ascatalyst It is synthesized from styrene-divinylbenzene bysuspension polymerization and finally sulfonated by sulfuricacid The esterification reaction of butyric acid with ethanolwas studied using different catalysts The catalytic activity ofAmberlyst 15 is higher than the Amberlyst 35 It is due toAmberlyst 15 has higher surface area and pore volume thanAmberlyst 35 So Amberlyst 15 is found to be the best catalystto generate the data

3 Apparatus and Procedure

Esterification reaction of butyric acid with ethanol withthe initial concentrations of 144molL and 1484molLrespectively was carried out in three-necked flask of 500mLcapacity fitted with a reflux condenser a thermometer and amagnetic stirrer The initial volume of reaction mixture wasapproximately 150mL A reflux condenser is used to avoid theloss of volatile compounds The ion exchange resin suspendsin the reaction mixture with the help of stirrer Temperatureinside the reactor is controlled within the accuracy of plusmn05 KIn all the experiments a known amount of butyric acid andthe catalyst charged into the reactor and heated to the desiredtemperature All of the reactants charged in the reactor arevolumetrically measuredThis time is considered the startingpoint of the reaction Samples were withdrawn at a regulartime intervals for analysis The progress of the reaction wasfollowed by withdrawing small enough samples to considerthem negligible compared to the volume of the reactionmixture at regular intervals

4 Analysis

All samples were measured in measuring cylinder of 1mLtaken periodically and titrated against 1 N standard NaOHsolution using phenolphthalein as an indicator

0

0001

0002

0003

0004

0005

0006

0007

0 05 1 15 2CA0 (molL)

minusr A

0(m

olLmiddotm

in)

Figure 1 Effect of acid concentration on initial reaction rate (1198621198610=

1484molL)

5 Kinetic Modeling

A pseudo-homogeneous model cab was effectively applied tocorrelate the kinetic data of the liquid solid catalytic reactionThe esterification reactions are known to be reversible reac-tion of second orderThe general rate expression can be givenby

119860 + 119861 997888rarr 119864 +119882 (1)

where 119860 = butyric acid 119861 = ethanol 119864 = ethyl butyrate and119882 = water and

minus119903119860=

119870119891 (119898119881) (119862119860119862119861 minus (119862119864 (119862119882119870119890)))

1 + 119870119861119862119861+ 119870119882119862119882

(2)

where subscript 119862119860and 119862

119861refer to acid and alcohol concen-

trations respectively 119870119891is forward reaction rate constant

119870119890is the equilibrium constant of the reaction 119870 is the

adsorption equilibrium constants 119898 is the quality of dryresin and 119881 is the volume of the resin

For the initial reaction rate with no product present (2)can be reduced to

minus1199031198600

= (

1198701198911198981198621198610119881

1 + 1198701198611198621198610

)1198621198600 (3)

A plot of minus1199031198600

versus 1198621198600

provides a straight line with slopeof (1198701198911198981198621198610119881(1 + 119870

1198611198621198610)) These lines were presented in

Figure 1 at temperature 348KIf (3) is rearranged for variables 119862

1198610values the following

expression can be obtained

11986211986001198621198610

minus1199031198600

=

119881

119870119891119898

+ (

119881119870119861

119870119891119898

)1198621198610 (4)


1198610produces a straight line

with the slope of 119881119870119861119870119891119898 and intersection of 119881119870

119891119898

These lines are presented in Figure 1 at 348K From the slopeand lines shown in Figure 2 the following equation can beheld


3195

3200

3205

3210

3215

3220

3225

3230

13 135 14 145 15CB0 (molL)

minusr A

0(m

ol m

inL

)CA0lowastCB0

Figure 2 11986211986001198621198610minus1199031198600


loading = 732 kgm3


minus1199031198600

=

119870119891 (119898119881)11986211986001198621198610

1 + 1198701198611198621198610+ 1198701198821198621198820

(5)


11986211986001198621198610

minus1199031198600

=

119881 (1 + 1198701198611198621198610)

119870119891119898

+ (

119881119870119882

119870119891119898

)1198621198820 (6)




1198611198621198610)119870119891119898 These


1198701198911198981198621198610

119881 (1 + 1198701198611198621198610)

= 00045

119881

119870119891119898

= 301206

119881119870119861

119870119891119898

= 1440

119881 (1 + 1198701198611198621198610)

119870119891119898

= 320113

119881119870119882

119896119891119898

= 2218

(7)


119870119891= 453 times 10

minus6 L2mol

119870119861= 478 times 10

minus6 Lmol119870119882= 735 times 10

minus6 Lmol




minus1199031198600

= 119870119891

119908

119881

1198621198610119862119860 (8)

0004

00041

00042

00043

00044

00045

00046

00047

0 05 1 15

minusr A

0(m

olLmiddoth

)

CW0 (molL)


Putting 119862119860= 1198621198600(1 minus 119883

119860)

minus1198621198600

119889119909119860

119889119905

= 119870119891

119908

119881

11986211986101198621198600(1 minus 119883

119860)

minus

119889119909119860

119889119905

= 119870119891

119908

119881

1198621198610(1 minus 119883

119860)

int

119909119860

0

minus

119889119883119860

(1 minus 119883119860)

= int119870119891

119908

119881

1198621198610119889119905

minus ln (1 minus 119883119860) = 119870

119891

119908

119881

1198621198610119905

(9)



119870








3195

3200

3205

3210

3215

3220

3225

3230

0 05 1 15


0(m

olmiddotm

inL

)

CW0 (molL)



loading = 732 kgm3









0

10

20

30

40

50

60

70

80

0 200 400

Frac

tiona

l con

vers

ion

Time (min)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)





0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


0

005

01

015

02

025

03

035

04


Rate

cons

tantK

(minminus1)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)


0

02

04

06

08

1

12

14

16

18

2

0 100 200 300 400Time (min)

minus(ln(1minusXA))


0

0001

0002

0003

0004

0005

0006


Rate

cons

tantK

(hrminus1)


0010203040506070809

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)



0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)




119870 = 1198960exp(minus

1198640

119877119879

) (10)




119860) versus 119905 to




7 Conclusion


References












RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










3195

3200

3205

3210

3215

3220

3225

3230

13 135 14 145 15CB0 (molL)

minusr A

0(m

ol m

inL

)CA0lowastCB0

Figure 2 11986211986001198621198610minus1199031198600


loading = 732 kgm3


minus1199031198600

=

119870119891 (119898119881)11986211986001198621198610

1 + 1198701198611198621198610+ 1198701198821198621198820

(5)


11986211986001198621198610

minus1199031198600

=

119881 (1 + 1198701198611198621198610)

119870119891119898

+ (

119881119870119882

119870119891119898

)1198621198820 (6)




1198611198621198610)119870119891119898 These


1198701198911198981198621198610

119881 (1 + 1198701198611198621198610)

= 00045

119881

119870119891119898

= 301206

119881119870119861

119870119891119898

= 1440

119881 (1 + 1198701198611198621198610)

119870119891119898

= 320113

119881119870119882

119896119891119898

= 2218

(7)


119870119891= 453 times 10

minus6 L2mol

119870119861= 478 times 10

minus6 Lmol119870119882= 735 times 10

minus6 Lmol




minus1199031198600

= 119870119891

119908

119881

1198621198610119862119860 (8)

0004

00041

00042

00043

00044

00045

00046

00047

0 05 1 15

minusr A

0(m

olLmiddoth

)

CW0 (molL)


Putting 119862119860= 1198621198600(1 minus 119883

119860)

minus1198621198600

119889119909119860

119889119905

= 119870119891

119908

119881

11986211986101198621198600(1 minus 119883

119860)

minus

119889119909119860

119889119905

= 119870119891

119908

119881

1198621198610(1 minus 119883

119860)

int

119909119860

0

minus

119889119883119860

(1 minus 119883119860)

= int119870119891

119908

119881

1198621198610119889119905

minus ln (1 minus 119883119860) = 119870

119891

119908

119881

1198621198610119905

(9)



119870








3195

3200

3205

3210

3215

3220

3225

3230

0 05 1 15


0(m

olmiddotm

inL

)

CW0 (molL)



loading = 732 kgm3









0

10

20

30

40

50

60

70

80

0 200 400

Frac

tiona

l con

vers

ion

Time (min)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)





0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


0

005

01

015

02

025

03

035

04


Rate

cons

tantK

(minminus1)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)


0

02

04

06

08

1

12

14

16

18

2

0 100 200 300 400Time (min)

minus(ln(1minusXA))


0

0001

0002

0003

0004

0005

0006


Rate

cons

tantK

(hrminus1)


0010203040506070809

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)



0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)




119870 = 1198960exp(minus

1198640

119877119879

) (10)




119860) versus 119905 to




7 Conclusion


References












RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












3195

3200

3205

3210

3215

3220

3225

3230

0 05 1 15


0(m

olmiddotm

inL

)

CW0 (molL)



loading = 732 kgm3









0

10

20

30

40

50

60

70

80

0 200 400

Frac

tiona

l con

vers

ion

Time (min)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)





0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


0

005

01

015

02

025

03

035

04


Rate

cons

tantK

(minminus1)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)


0

02

04

06

08

1

12

14

16

18

2

0 100 200 300 400Time (min)

minus(ln(1minusXA))


0

0001

0002

0003

0004

0005

0006


Rate

cons

tantK

(hrminus1)


0010203040506070809

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)



0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)




119870 = 1198960exp(minus

1198640

119877119879

) (10)




119860) versus 119905 to




7 Conclusion


References












RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


0

005

01

015

02

025

03

035

04


Rate

cons

tantK

(minminus1)


0

01

02

03

04

05

06

07

08

09

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)


0

02

04

06

08

1

12

14

16

18

2

0 100 200 300 400Time (min)

minus(ln(1minusXA))


0

0001

0002

0003

0004

0005

0006


Rate

cons

tantK

(hrminus1)


0010203040506070809

0 100 200 300 400 500Time (min)

Frac

tiona

l con

vers

ion

(XA

)



0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)




119870 = 1198960exp(minus

1198640

119877119879

) (10)




119860) versus 119905 to




7 Conclusion


References












RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

02

04

06

08

1

12

14

16

18

0 100 200 300 400Time (min)

minusln(1minusXA)


53545556575859

66162

285 29 295 3 305 311000 (T)

minusln

(K)




119870 = 1198960exp(minus

1198640

119877119879

) (10)




119860) versus 119905 to




7 Conclusion


References












RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









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