Chemical reaction engineering, 2012
Home task 2
Maan
Reaction of bromine with m-xylene in the presence of iodine catalyst was studied at 27ºC
in a laboratory scale batch reactor.
Small amounts of bromine and iodine were added to to a batch reactor in which there was
excess of m-xylene. In the course of the reaction iodine and m-xylene concentrations
were about constant. Reaction media was all the time in constant density and volume, and
for the dcrease of bromine in the raction we get:
−
dc Br2
dt
= k (c Br2 ) n
(1)
, where k pseudo reaction rate constant that includes iodine and m-xylene concentrations
and n is the order of reaction.
Table 1.
Br2 concentrations as a function of time in the batch reactor. Br2 was added at
time moment 0. t (min), cBr2 (mol/L).
t
0.00
2.52
7.56
10.08
12.60
17.64
20.16
22.68
25.20
32.76
35.28
40.32
42.84
45.36
47.88
52.92
55.44
57.96
63.00
CBr2
0.3335
0.2906
0.2258
0.2010
0.1799
0.1465
0.1331
0.1214
0.1111
0.0869
0.0805
0.0696
0.0650
0.0608
0.0569
0.0503
0.0473
0.0447
0.0399
a)
Determine k and n by linearizing eq. (1).
b)
Use nonlinear regression to determine k and n.
Hints:
§
§
§
Easy way is to use Polymath nonlinear regression mode.
Use differential method. Fit first the batch data to 5th degree polynomial and
dcBr2
 dc Br2 
 .
for each data point − 
Polymath calculates the derivatives −

dt
 dt  cBr 2
In a) use linear regression (Linear & Polynomial), in b) use nonlinear regression
(Nonlinear)
Return to Kimmo Klemola (room 2117) by 12.010.2012. Must be accepted
30.10.2012.