Similar products are also formed by heating gutta-percha which closely resembles caoutchouc in its chemical structure.
To charge a lot of them as a whole in a heating furnace, bring them as a whole to rolling temperature, and then withdraw them as a whole for rolling, is very wasteful of heat, because it is only in the first part of the heating that the outside of the ingots is cool enough to abstract thoroughly the heat from the flame.
The osotriazoles are obtained by heating the osazones of orthodiketones with mineral acids; by the action of acetic anhydride on the hydrazoximes of orthodiketones, or by condensing diazo-methane with cyanogen derivatives (A.
The hardening of steel consists in first transforming it into austenite by heating it up into region 4 of fig.
Mehner patented heating the oxides of silicon, boron or magnesium with coal or coke in an electric furnace, and then passing in nitrogen, which forms, with the metal liberated by the action of the carbon, a readily decomposable nitride.
CO 2 Na being thus formed; by continuing the heating under pressure this carbonate gradually changes into mono-sodium salicylate.
Esters may be prepared by heating the silver salt of an acid with an alkyl iodide; by heating the alcohols or alcoholates with an acid chloride; by distilling the anhydrous sodium salt of an acid with a mixture of the alcohol and concentrated sulphuric acid; or by heating for some hours on the water bath, a mixture of an acid and an alcohol, with a small quantity of hydrochloric or sulphuric acids (E.
Spiegel, Ber., 1881, 14, 23 9), by heating benzoylformaldehyde with alkalis (H.
Metallic cobalt may be obtained by reduction of the oxide or chloride in a current of hydrogen at a red heat, or by heating the oxalate, under a layer of powdered glass.
The heating as well as the illuminating value of the gas per unit volume is lowered by over-baking, and Dr Bueb gives the following figures as to the heating value of gas obtained from the same coal but by different methods of carbonization: Vertical Retorts, 604 British thermal units per cub.