De bepaling van het verzepingsingsgetal
The saponification value IS is the number that expresses in milligrams the quantity of potassium hydroxide required to neutralise the free acids and to saponify the esters present in 1 g of the substance.
Introduce the prescribed quantity of the substance to be examined (m g) into a 250 ml borosilicate glass flask fitted with a reflux condenser. Add 25.0 ml of 0.5 M alcoholic potassium hydroxide and a few glass beads. Attach the condenser and heat under reflux for 30 min, unless otherwise prescribed. Add 1 ml of phenolphthalein solution R1 and titrate immediately with 0.5 M hydrochloric acid (n1 ml of 0.5 M hydrochloric acid). Carry out a blank test under the same conditions (n2 ml of 0.5 M hydrochloric acid).
IS = 28.05 (n2 - n1) / m
10 september 1999