Chemistry and Physics. 443 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. Tfte Improvement of High Boiling Petroleum Oils. — For 

 a long time it has been known that a sufficient heating of high 

 boiling oils, a process called cracking, will cause them to break 

 down into lower boiling oils or even gases with the deposition of 

 carbon. A difficulty in tbe practical application of this cracking 

 process lies in the fact that in breaking down the high boiling 

 hydrocarbons into simpler ones there is not enough hydrogen to 

 saturate the newly formed bodies, in spite of the deposition of 

 carbon, so that the products contain large amounts of unsaturated 

 hydrocarbons, which give them undesirable qualities. Such pro- 

 ducts can, of course, be refined somewhat with sulphuric acid, 

 but there must be too much acid used and too much oil lost to 

 permit in practice a thorough treatment with the acid. A. M. 

 McAfee has applied Friedel and Craft's reaction, that is, treat- 

 ment with anhydrous aluminium chloride during the distillation, 

 for the purpose of converting high boiling into low boiling oils, 

 and he has found that with proper control of the vapors leaving 

 the distilling system and entering the final condenser, and with 

 sufficient time given the aluminium chloride, there is a complete 

 transformation, and no matter how unsaturated the high boiling 

 hydrocarbons may be, the low boiling oils produced from them 

 are sweet smelling, water white and saturated. The reaction 

 gives little gas, and only about the right amount of carbon is de- 

 posited to allow for the production of saturated products. In 

 carrying out the process in practice, the crude oil is first heated 

 in the still to render it anhydrous, and also distil off any gasoline 

 and kerosene that it may contain originally. In many of our crude 

 oils, especially some of those from Texas, California, and Mexico, 

 there is practically no gasoline and very little kerosene present. 

 Anhydrous aluminium chloride is then added to the extent, ap- 

 parently, of 5 to 1\ per cent, the mixture is stirred and heated to 

 boiling, usually at a temperature of about 500° F. The still is 

 provided with large, air cooled, trap condensers which cause the 

 condensation and the return to the boiler of the higher boiling- 

 products and of the aluminium chloride and its compounds. 

 When the vapors are allowed to pass into the final condenser at a 

 temperature of about 300° F. the product is gasoline alone, which 

 is ready for market when washed with an alkaline solution. The 

 operation is carried on until the least valuable, so-called gas oil, 

 portion of the oil has been converted into the low boiling distil- 

 late, then the operation is stopped, and the more valuable higher 

 boiling part is drawn off from the coky residue containing the 

 aluminium chloride, in order that it may be worked up for 

 lubricating oil and paraffine products. The latter products are 



