A SIMPLE BURNER for BLOWPIPE REACTIONS IRVING A. COWPERTHWAITE Columbia University, New York City
There are many high-temperature oxidation-reduction and fusion reactions in the scope of general chemistry which should f o m an important part of the laboratory work in the subject. Such reactions include, for example, the oxidation of the metals, their reduction from their compounds, and many kinds of combination and displacement reactions between anhydrides. This kind of work has been quite generally neglected in elementary laboratory courses because the blowpipe
or various types of blow-torches usually employed to direct the necessary fine hot flames upon the reacting masses are special pieces of apparatus requiring considerable technic for effective use. A simple burner giving an intense flame that can be easily applied to a desired material is needed to make these experiments available. It is the purpose of this note to describe a torch that has been developed in our laboratory for student use in the field of high-temperature reactions. The device has proved to be entirely satisfactory and is so simple that any student can make one in a few moments.
The burner is shown in the accompanying diagram. It is made from a piece of glass tubing, A , of about 3 4 mm. bore drawn down to a fine tip, B. The tip at B should be closed down by rotating in a Bunsen flame until it is of such a size that the full pressure of the gas behind i t will give a blue flame about an inch to an inch and a half in length. Such a flame will have a welldefined inner cone, C, with a pale yellowish tip, and a nearly invisible outer cone, D. Oxidation experiments are effectively carried out a t the tip of the o-uter cone and reduction reactions a t the tip of the inner cone. It should be emphasized that this burner requires no air and so relieves the student of the tiring and disagreeable task of blowing. The flame from this burner will reduce copper compounds and yield the metal as a molten globule. As the melting point of copper is 1083'C., the temperature of the flame is a t least llOO°C. However, although the temperature of the flame is high, its capacity is rather low and i t should only be used on small samples of the reacting material supported on a heat insulator such as a block of charcoal. All the usual blowpipe experiments such as the oxidation of metals, reduction of their salts, reduction of sulfur compounds to sulfides, production of green cobalt zincate and blue cobalt aluminate, as well as such fusion reactions as the making of glass and the disintegration of silicates with sodium carbonate are easily and comfortably performed with this little glass burner.
