162 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Diethyl Peroxide. — Bajeyer and Villiger have succeeded 

 in preparing this interesting derivative of hydrogen peroxide by 

 the action of the latter upon diethyl sulphate with the gradual 

 addition of potassium hydroxide. The substance, (C 2 H 5 ) 2 2 , is a 

 colorless, mobile liquid, boiling at 65°, which does not solidify in 

 a mixture of solid carbon dioxide and ether. It is difficultly solu- 

 ble in water, but miscible with alcohol and ether. It has a faint 

 odor resembling ethyl bromide, and its specific gravity at 15° 

 compared with water at 4° is -82 13. In its chemical behavior it 

 is remarkably inactive for a peroxide. It does not react with 

 permanganate, chromic acid or titanium sulphate. Acidified 

 potassium iodide solution is not changed by it until after long 

 standing. Metallic sodium has no action upon the pure sub- 

 stance, and sodium amalgam in the presence of water does not 

 reduce it. Alkaline pyrogallate solution is not darkened by it 

 until after long standing, when an intense color is produced .and 

 alcohol is formed. The substance, like all peroxides, is quickly 

 reduced by the action of glacial acetic acid and zinc dust, the 

 product being alcohol. The low kindling-point of the substance 

 is very striking. If the bulb of a thermometer warmed to 250° 

 is brought near the liquid, it ignites and burns very rapidly but 

 noiselessly with a large, luminous flame. Carbon disulphide 

 under the same conditions could not be kindled until a tempera- 

 ture of 300° was reached. If a hot copper wire is brought near 

 the liquid for an instant in an atmosphere of carbon dioxide, the 

 substance disappears very quickly after the wire is removed with- 

 out producing sound or light, and without boiling. This is appar- 

 ently a sort of slow explosion, which is almost magical in the 

 impression made upon the observer. This internal combustion 

 produces a large amount of formaldehyde, and, besides this, prin- 

 cipally carbon monoxide and ethane. A mixture of the vapor of 

 the substance with air explodes with violence, while with oxygen 

 it explodes more strongly than detonating gas. The authors 

 were unable to explode the liquid by the blow of a hammer even 

 when fulminating silver was present, but it is their opinion that 

 this apparently harmless substance may be very dangerous under 

 certain conditions, just as acetylene is. 



The properties of diethyl peroxide indicate that the older struc- 

 tural formula for hydrogen peroxide, HO . OH is more probable 

 than a newer one that has been advanced, H 2 : O : O, in which one 

 of the oxygen atoms is assumed to be quadrivalent. For, if the 

 ethyl compound had a structure analogous to the latter it seems 

 probable that its reduction product would be ethyl ether instead 

 of alcohol; moreover it would be expected that (C 2 H B ) 2 : O 

 would act upon alkaline pyrogallate as rapidly as molecular 

 oxygen, 0:0. 



