Ground-glass joints reagent

Apparatus. The apparatus is made of Pyrex glass, in one piece. It consists of a shaped bulb A (Fig. 89 of about 30 ml. capacity in which the reaction takes place, provided with an inclined inlet B at the side and a vertical ascension tube D. B serves not only as an inlet for the admission of the carrier gas but also as the route by which the reagents and test sample are introduced into the apparatus. B ends in a small ground-glass joint into which fits ajoint carrying a capillary-tube which projects well down into the bulb A (the end of the capillary should be just above the liquid level when the apparatus is charged for the determination). The upper extension of this capillary beyond the joint is provided with a tap C to control the rate of flow of the carrier gas. 

Locating an organic compound, 1128 Lubrication of ground glass joints, 225 Lucas test, 261 reagent, 261 ... 

Prior to 1930, and even later, many laboratory experiments were bedeviled with the glass apparatus available at that time. The component parts of the apparatus were, of necessity, connected together by corks and rubber stoppers these connections were attacked by many chemical substances, particularly acids and solvents. Efforts to do work under reduced pressure also suffered and the purity of the products left much to be desired. The introduction of ground-glass joints solved many of these problems they were probably an extension of the simple and common ground-glass stoppers found in reagent bottles. 

A 500-ml. round-bottomed flask is attached by a well-lubricated ground-glass joint to a reflux condenser with a side take-off having a stopcock which may be opened to permit distillation. In the flask are placed 170 ml. of commercial diethylene glycol and 30 g. (0.46 mole) of potassium hydroxide (u.s.p., or reagent grade, 85%). This mixture is heated carefully (Caution Note 1) until the potassium hydroxide begins to melt and go into solution then the heat is removed intermittently until the exothermic dissolution is completed. After the solution has been cooled to 80-100°, the condenser is removed and there are added to the flask 35 g. (0.152 mole) of 6-ketohendecanedioic acid and 22 ml. (22.4 g., 0.38 mole) of commercial 85% hydrazine hydrate. 4 he condenser is immediately replaced, and the mixture is... 

---