Analisis angka asam (total acid number) dg potensiometer , Titrino/titroprocessor

Alat yg digunakan
Potentiometer = 751 GPD Titrino / Titroprocessor
Electrodes = 6.0133.100 pH glass electrode; input 1
6.0729.100 Ag/AgCl reference electrode ( LiCl sat in ethanol); input 2
6.0331.000 Pt auxiliary electrode; input Ref.
Differential potentiometry

Pereaksi
c(TBAOH) = 0.1 mol/L in isopropanol/methanol; D0
TBAOH = Tetrabutyl ammonium hydroxide

Sampel
app. 1.5 g of used motor oil
50 mL solvent: chlorobenzene : isopropanol (2 : 1)

Remarks
· Calculations:

TAN=(EP1-C01)*C02*C03/C00;2;mg/g

TAN = acid of sample, calculated as mg KOH per g of sample
C01 = blank value, consumption of titrating agent by solvent mixture (0 mL)
C02 = concentration of titrating agent (0.1 mol/L)
C03 = molecular mass of KOH (56.106 g/mol)

. Answer

TAN = (0.680) x 0.1 x 56.106 / 1.6646 = 2.29 mg/g

EP1 = 0.680 mL
C00 = 1.6646 g

· Store glass electrode in dist. water over night. Before titrating,
precondition it in solvent during 10 - 30 min.
· The 6.0430.100 Ag Titrode may be used instead of the 6.0133.100
and 6.0331.000 electrodes. In this case, you make differential
potentiometry with only two electrodes, the Ag Titrode and the
6.0729.100 reference electrode.

Literature

· Metrohm Application Bulletin No. 80: Determination of the acid / base
number in petroleum products (TAN/TBN)
· ASTM D 2896 - 80
· DIN 51596