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-NN+]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 to L, and for % (0.001*100=0.1)
C03 = concentration of titrating agent (0.2 mol/L)
Enter the appropriate molecular mass for other amines (C01).
Instead of the Pt Titrode the 6.0420.100 combined Pt electrode can be used.

. Answer

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

EP1 = 14.396 mL
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
dos.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
============