Microscopic Identification of Certain Sugars and Polyhydric Alcohols

Abstract

VOL. 12, NO. 9 height. Then about 6 t o 10 m of the ester are introduced and the tottle is weighed again. The bottle is stoppered and heated in a brass or copper block ( Figure 2) to 60" to 70" C. The stopper is then opened momentarily, closed tightly again, and heated to 13O0, at which tem erature it is held for 2 minutes. It is agowed to cool, the stopper being occasionally removed momentarily to prevent later dificulty in its removal. The stopper is washed off into the bottle. The contents of the latter are then washed out into a 10-ml. Erlenmeyer flask. Care should be taken to keep the volume of the liquid small, not exceeding 2 ml. It is then titrated with 0.02 N acid, using phenolphthalein as indicator. A blank is run on the reagent to determine the amount of potassium hydroxide per gram of the reagent.Attempts to measure the reagent volumetrically gave poor results because of the difficulty of getting the same volume of such a viscous liquid from a capillary pipet each time the experiment was tried. Care must be taken throughout the determination t o r t loss of easily volatile esters.hen introducing the sample into the weighing bottle, a capillary pipet should be used and the Sam le delivered from the pipet directly over t ! e diethylene glycol reagent, BO that solution in the reagent takes place as quickly as possible.