Metrohm 784 KFP Titrino - Manual (Page 141)

6.3 User methods
784 KFP Titrino
138
6.3.8 Determination of the bromine number "BrNumber"
Determination of the bromine number in pe-
troleum hydrocarbons according to ASTM D
1159-84.
The bromine number is defined as the quan-
tity of bromine in mg which reacts with 100 g
of the sample.
Electrode:
Double Pt-electrode 6.0338.100 at measuring
input "Pol".
Titrating agent:
Bromide/bromate-solution,
c(BrO
3
– /Br – ) = 0.5 mol/L
Dissolve 51.0 g KBr and 13.92 g KBrO
3
each
in distilled water and add up to 1 L.
Solvent:
714 mL glacial acetic acid,
134 mL 1,1,1-trichlorethane,
134 mL methanol,
18 mL w(H
2
SO
4
) = 0.2 (20%)
Sample:
Pipet 25 mL 1,1,1-Trichloroethane into a
50-mL volumetric flask and add the sample
(see table below). The weight of the sample is
obtained by difference between the weight of
the flask before and after addition of the sam-
ple. Fill the flask to the mark with
1,1,1-trichloroethane and mix well.
Add 5 mL of the sample solution to 110 mL
solvent in the titration vessel and mix.
The blank sample is titrated in the same way.
– Result in % (g bromine/100 g sample)
– Sample size in g
– Consumption of Blank sample in mL
– Normality of the titrating agent in mol/L
– Molecular mass of Br (79.9 g/mol) ∗ 0.1
(Conversion to % in weight and L)
– C04 = Dilution factor (Has to be calculated ac
cording to the sample preparation, for the
method described above, the factor is 10.)
Bromine no. (%, w/w) Sample size (g)
0...10 20...16
10...20 10...8
20...50 5...4
50...100 2...1.5
100...200 1.0...0.5
References:
ASTM D 1159-84
Metrohm Application Bulletin No. 177
'pa
784 KFP Titrino 784.0010
date 1999-08-18 time 14:52 0
KFT Ipol BrNumber
parameters
>control parameters
EP at U 500 mV
dynamics 500 mV
max.rate 5 ml/min
min.volume incr. min. µl
stop crit: time
t(delay) 30 s
>titration parameters
titr.direction: -
pause 1 0 s
start V: OFF
pause 2 0 s
extr.time 0 s
I(pol) 10 µA
electrode test: OFF
temperature 25.0 °C
time interval 2 s
>stop conditions
stop V: abs.
stop V 99.99 ml
filling rate max. ml/min
>statistics
status: ON
mean n= 3
res.tab: original
>preselections
conditioning: OFF
req.ident: OFF
req.smpl size: value
limit smpl size: OFF
activate pulse: OFF
------------
'fm
784 KFP Titrino 784.0010
date 1999-08-18 time 14:52 0
KFT Ipol BrNumber
>calculations
BrNumber=(EP1-C01)*C02*C03*C04/C00;0;
C00= 1.0
C01= 0.0
C02= 0.5
C03= 7.99
C04= 100
------------
'de
784 KFP Titrino 784.0010
date 1999-08-18 time 14:52
KFT Ipol BrNumber
def
>formula
BrNumber=(EP1-C01)*C02*C03*C04/C00
RS1 text BrNumber
RS1 decimal places 0
RS1 unit:
RS1 limit control: OFF
>silo calculations
match id: OFF
>common variables
>report
report COM1:full;
>mean
MN1=RS1
>temporary variables
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