Standard ground-glass joints

For dehydration, place the platinum (nickel) crucible with the prepared salt ( 5 g) into a test tube with a standard ground-glass joint (Fig. 63). Preliminarily weigh the crucible and the salt with an accuracy up to 0.01 g. Connect the test tube to a vacuum system. Evacuate it (10- mmHg) first at room temperature during 10-20 min, and then at 150 °C on an oil bath or a bath with Wood s alloy. Dehydrate the substance up to a constant mass. Calculate the composition of the product according to the change in its mass. 

Put the dried activated carbon loosely on a glass wool substrate into each of the bulbs of a cooler on standard ground glass joints (the number of bulbs should be at least six). The carbon should occupy at most one-half of the volume of a bulb. Camphor may be used instead of the activated carbon. 

Rapidly connect the receiver with the silicochloroform via standard ground-glass joint 3 to an apparatus for fractional distillation under atmospheric pressure (see Fig. 20) and close side arm 4 (see Fig. Ill) with a glass stopper. Perform distillation and gather the fraction boiling at 34-37 °C. 

The apparatus consists of a glass reaction flask fitted with a side arm and dropping funnel. The side arm is connected to two glass traps in series by means of standard ground-glass joints and stopcocks. 

Do not attempt to use non-standard ground-glass joints in the standard jointware, it will not fit correctly. For example, ground-glass stoppers from volumetric flasks do not seal Quickfit1 separatory funnels. 

The apparatus for the preparation is assembled as shown in Fig. 7. Standard ground-glass joints are used through-... 

Today, apparatus having standard ground-glass joints is used almost exclusively in every organic laboratory and hence in every distillation laboratory (Tab. 1). An encyclopaedia of chemical laboratory apparatus including the G.D.R. standards has been edited by Telle [3]. 

Sizes of standard ground-glass joints for interchangeable connections... 

A gas generator equipped with standard ground glass joints, which permits complete utilization of the acid and easy replenishment, has recently been made commercially available. 

Fig. 101. Karlsruhe apparatus for isolation of small amounts of steam-volatile lipids, a standard ground glass joint B 29 6 ascending tube c inlet for washing d condenser e pressure compensator with 1 ml graduations / graduated capillary with divisions of 1/200 g bulb h three-way tap i outlet I filling tube w microflask for gravimetric estimation of collected lipids If/S water level in flask [245]...

---