Potentiometric Determination of the 2-Aminophenol

Potentiometric Determination of the 2-Aminophenol

Equipment
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0431.100 Pt Titrode; input 1

Reagents
c(NaNO2) = 0.2 mol/L; D0

Sample
app. 0.3 ... 0.35 g sample (2-aminophenol)
10 mL w(HBr) = 0.20 (20%)
30 mL dist. water

Remarks
Determination reaction:

H+R-NH2 + HNO2 + HBr ......[R-NN+]Br- + 2 H2O

Calculations:

Content=EP1*C01*C02*C03/C00;2;%

Content = content of 2-aminophenol in %
C01 = molecular mass of 2-aminophenol (109.13 g/mol)
C02 = factor for conversion mL , and for % (0.001*100=0.1)
C03 = concentration of titrating agent (0.2 mol/L)
Instead of the Pt Titrode a combined Pt electrode 6.0420.100 can be used.

Answer

Content = 14.396 x 109.13 x 0.1 x 0.2 / 0.3188 = 98.56%

EP1 = 14.396
C00 = 0.3188 g

Literature
Metrohm Application Bulletin No. 228: Diazotisation titrations

Method documentation

'pa
751 GPD Titrino 15215 751.0010
MET U Diazo
parameters
>titration parameters
V step… 0.10 ml
dos.rate max…. ml/min
signal drift ….OFF mV/min
equilibr.time ….15 s
start V:…. OFF
pause ….30 s
os.element:…. internal D0
meas.input: …1
temperature ….25.0 °C
>stop conditions
stop V: ….abs.
stop V ….17 ml
stop U …OFF mV
stop EP …9
filling rate max…. ml/min
>statistics
status: …OFF
>evaluation
EPC …30 mV
EP recognition:… all
fix EP1 at U OFF …mV
pK/HNP: …OFF
>preselections
req.ident: …OFF
req.smpl size:… value
activate pulse: ….OFF
------------
'fm
751 GPD Titrino 15215 751.0010
MET U Diazo
>calculations

Content=EP1*C01*C02*C03/C00;2;%

C00= 0.3188

C01= 109.13

C02= 0.1

C03= 0.2

------------

'fr

751 GPD Titrino 15215 751.0010

U(init) 125 mV MET U Diazo

smpl size 0.3188 g id#1 09120

EP1 14.396 ml -203 mV

Content 98.56 %

stop V reached

============

'cu

751 GPD Titrino 15215 751.0010

start V 10.000 ml MET U Diazo

2.0 ml/div dU=100.0 mV/div