Tugas_2_Teknik Reaksi Kimia Lanjut_Fatoni Nugroho

TUGAS 2 TEKNIK REAKSI KIMIA LANJUT

Disusun Oleh : Fatoni Nugroho

Dosen enga!"u: Dr# Ista$i% S#T#% M#T#

JURUSAN TEKNIK KIMIA FAKULT FAKULTAS TEKNIK& UNI'ERSITAS DIONEGORO SEMARANG 2()*

The following data for the hydrogenation of i-octene to form i-octane were obtained using a differential reactor operated at 200°C. Table 1. Experimental ata

1.

e!elop a reaction rate law appropriate with this reaction "possibility controlling mechanism# "a$ if adsorption controlling% "b$ if surface reaction controlling% and "c$ if  desorption controlling

2.

&uggest a mechanism consistent with the abo!e experimental data

'.

E!aluate the reaction rate law model parameters according to the abo!e experimental data. (sage of )olymath software was recommended to sol!e the fitting.

Ans+er : Rea,tion

i-octene * hydrogen + * ,

i-octan C

)# De-elo" rea,tion rate la+ a""ro"iate +ith this rea,tion we as what ualitati!e conclusions can be drawn from the

data about

the

dependence of the rate of disappearance of i-octene/ -r + on the partial pressures of  i-octene/ hydrogen/ and i-octane.

1$ ependence on the product i-octane

n runs 1/ 2/  and 10/ we obser!e that for fixed concentrations "partial  pressures$ of i-octene and hydrogen the rate decreases with increasing concentration of i-octane. + rate expression in which the i-octane partial  pressure appears in the denominator could explain this dependency#

The type of dependence of -r + on ) C gi!en by Euation "1$ suggests that ioctane is adsorbed on the clinoptilolite surface. 2$ ependence on hydrogen n runs 2 and '/ or 1 and / we obser!e that rate increases with increasing concentration of hydrogen. &o we can conclude that hydrogen is adsorbed on the surface. 3ith combining euation "1$ suggests that the rate law may be of the form

'$ ependence on i-octene. n runs 2 and 4/ we obser!e that in the low concentration/ rate increases with increasing concentration of i-octene. ,ut in runs 1 and 5/ increasing concentration i-octene will decreasi the rate. 3e can assume that only low concentration of i-octene will absorbed on surface/ if high concentration of ioctene/ it can disturb reaction. 3ith combining euation "2$ suggests that the rate law may be of the form

3e now propose a mechanism for the hydrogenation of i-octene. 3e assume that i-octene and hydrogen is adsorbed on the surface and then reacts to produce i-octane adsorbed on the surface. i-octaneis then desorbed from the surface. The rate law can  be #

a# a$sor"tion ,ontrolling There are 2 reactan that adsorbed on surface + * & +.&

,

*

&

,.&

+.&

*

,.&

.# sur/a,e rea,tion ,ontrolling C.&

,# $esor"tion ,ontrolling C.&

C

*

&

2# Me,hanis! ,onsistent +ith the a.o-e e0"eri!ental $ata &ince approximately 567 of all heterogeneous reaction mechanisms are surface

reaction limited rather than adsorption or desorption limited/ we begin by assuming the reaction between adsorbed i-octene and hydrogen to be reaction rate limited. 8or surface reaction mechanism/

we see that we need to replace C +& C ,&/ and C C& that we can measure. n Euation "$  by uantities that we can measure.

8or surface-reaction-limited mechanisms/ we use the adsorption rate Euation "4$ to obtain C+& and e."6$ for C ,& #

+nd we use desorption rate e."5$ to obtain C C&

The total concentration

&ubstitute e. "9$/ "10$/ and "11$ to "12$/ we obtain #

&ubstitution the substitute for C +&/ C ,&/and CC& in e. "$ to obtain the rate law for the case of surface-reaction control#

,y neglecting the reser!e reaction we ha!e

Then substitute e. "1'$

1# E-aluation o/ the rate la+ !o$el "ara!eter

•

The data from experiment were entered into the ):;<=+T> and use  ?onlinier regression #

Figure ) # In"ut $ata ol3!ath4

•

The rates of reaction " e. 14$ were entered in )olymath #

Figure 2# Mo$el in ol3!ath •

Enter =odel parameter  Table 2. =odel )arameter  =odel parameter

nitial guess



1

@+

1

•

@,

1

@C

1

efinite !ariable in )olymath must be lie this #

Figure 1# 'aria.el in ol3!ath • •

&ol!e the problem The )olymath Aesults are gi!en in 8igure ' #

Figure *# ol3!ath re"ort

&o we ha!e/

Figure 5# Gra"h Result