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"BETTER THINGS" FROM PETROLEUM 701

tive distillation of coal; for example, benzene, toluene, xylenes, alkyl

naphthalenes, and high-solvency naphthas high in aromatics.

Cresylic acid (a mixture of phenols), formerly obtained from coal

tar alone, is now obtained from petroleum at a lower cost. It is used

for the preparation of germicides and insecticides and on a large scale

in flotation processes for the recovery of ore particles from crushed rock.

In the process of cracking large molecules to form molecules suitable

for gasoline, the production of smaller fragments, which are too

volatile to be used in gasoline, is unavoidable. Between 7 and 8 per

cent by weight of the total crude oil processed in our refineries becomes

gas. This amounts to about 14,000,000 tons per year. One company

alone was making over one hundred synthetic chemicals from these

refinery gases in 1940.

Propane and butane, refinery gases formerly burned as fuels in the

refinery boilers, are now liquefied and sold as "bottled gas" for use

where neither natural gas nor manufactured gas is available and

even in trucks and buses; 128,000,000 gallons of "bottled gas" were

sold in 1939.

One interesting use for propane is the removal of wax, asphalts,

and resins from lubricating-oil stocks. Dewaxing Is effected by dissolving

the oil in liquefied propane, evaporating a portion of the

propane and thus chilling the mixture, and subsequently filtering or

settling the wax crystals so formed. Residual stocks are deasphalted

by partial solution in liquefied propane. Furthermore, by proper

selection of the concentration and temperature, the very heavy portions

of the oil, nonasphaltic but "resinous," may be separated from

the balance of the oil. Thus deasphalting and deresinating are in

effect a substitute for high-vacuum distillation. Olefinic and other

easily oxidized constituents of lubricating oils, as well as materials

having poor viscosity-temperature characteristics, are separated from

lubricating oils by solvent extraction. Examples of selective solvents

are sulfur dioxide, chlorex, furfural, and phenol. The result of the

combination of these processes is the production of extremely highquality

motor oils with excellent viscosity-temperature coefficients,

high stability, and low pour-point.

Already refinery gases (former waste products) are being used to

produce ethylene glycol (antifreeze), glycerine, acetone, and ethyl

alcohol. Instead of using alcohol derived from the fermentation of

carbohydrates to replace gasoline as a fuel, as has been done in other

countries, we have seen petroleum used to produce cheaper and purer

alcohol to compete with fermentation alcohol in all of its many applications.

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