462 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE 



I. Chemistry and Physics. 



1. The Manufacture of Gasoline and Benzene- Toluene from 

 Petroleum and Other Hydrocarbons. — W. F. Rittjian, C. B. 

 Dutton and E. W. Dean have published an abstract of Bulletin 

 114 of the U. S. Bureau of Mines and have added some supple- 

 mentary information in regard to new developments in the 

 " cracking" of oils on a commercial scale. In these processes the 

 heavy oil passes down through vertical iron tubes where it is heated 

 to a high temperature under high pressure. Large quantities of 

 carbon are deposited in the tubes during the decomposition, and 

 an important feature of the newly devised apparatus is a rotating 

 " stirring rod " passing through the tube and provided with 

 attached chains which scrape the inner wall of the tube and keep 

 it free from carbon. The carbon falls into a receptacle at the 

 bottom of the tube while the gases and vapors pass on to a con- 

 denser. Several tubes are heated together in a chamber by 

 means of gas burners. Many experiments have been made in 

 connection with the benzene-toluene process in regard to the 

 most suitable size and length of the tubes and the best tempera- 

 ture and pressure. It has been found that each increase in the 

 diameter of the tubes has given improved results, and in the latest 

 plant tubes of lOf inch internal diameter have been employed, 

 capable of converting 60 gallons of oil per hour per tube. For 

 producing benzene and toluene it appears that a temperature 

 between 650° and 750° C. is suitable while pressures up to 250 

 lbs. per square inch have been employed. For producing gaso- 

 line a lower temperature of about 500 to 575° C. is used with a 

 pressure of about 250 to 300 lbs. per square inch. The yields 

 appear to vary with the nature of the heavy oil emploj^ed. The 

 yields of gasoline appear to vary between 10 and 30 per cent of 

 the original oil, while the yields of benzene and toluene together 

 Avere frequently from 5 to 9 per cent.™ -Tour. Indust. and Eng. 

 Chem., viii, 351. h. l. w. 



2. A Rapid Method for the Determination of Copper and 

 Iron. — Graham Edgar has devised an interesting combination 

 of well-known reactions for this purpose, where both metals are 

 determined volumetric-ally in a single portion. The solution con- 

 taining copper and iron, together with some sulphuric acid, is 

 nearly neutralized with ammonia or sodium carbonate. It is 

 then saturated with sulphur dioxide and heated until it begins to 

 boil. Then a slight excess of standard solution of ammonium 

 thiocyanate is added to precipitate all the copper. The solution 

 is then boiled vigorously for ten minutes, while a current of car- 

 bon dioxide is passed through the solution. This operation is car- 

 ried out in a flask. The stream of carbon dioxide is continued 



