US2199108A - Stable petroleum product - Google Patents

Description

Patented Apr. 30, 1940* STABLE PETROLEUM PRODUCT Clarence M. Loane and Bernard H. Shoemaker,

Hammond, Indi, assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application December 13, 1937,

. Serial No. 179,473

7 Claims. (o1. 1964.149)

This invention relates to stable petroleum products and in particular oxidation stable white mineral oils and products containing the same.

White mineral oils, often also referred to as mineral medicinal oils and liquid paraffins, are usually prepared by treating petroleum distillates of the desired viscosity with fumingsulfuric acid, the amount of acid used ranging from about 2 lbs. to about 8 lbs. of acid per gallon of oil. White oils which will pass the U. S. Pharmacopoeia acid test (hereinafter referred to as U.'S.P. acid test) may be prepared by treating a distillate stock of about 100 seconds to about 800 seconds Saybolt viscosity at 100 F. with from about-' lbs. to about 8 lbs. of 104%; sulfuric acid per gallon of oil in /2 lb. dumps, neutralizing the acid treated oil with a neutralizing agent such as caustic, washing the neutralized oil with about volumes of 50-55% alcohol per 100volumes of oil and treating the neutralized oil with an absorbent material such as clay. Mineral medicinal oil so treated will give a color not greater than 3 N. 'P. A. by the U. S. P. .acid test which consistsof heating 5 cc. of oil and 5 cc. of chemically pure sulfuric acid in a glass stoppered cylinder for ten minutes in a water bath and shaking at second intervals. The oil must remain colorless and'the acid must not become darker than pale amber (almost 3 N. P. A.)

In additionto the mineral medicinal oils other grades of white oils are made which, because of their use, need not pass the U. S. P. acid test. These oils are referred to as technical white oils or commercial white oils and are obtained by treating petroleum distillates of thedesired viscosity range with from about 2 lbs. to about 5 lbs. of fuming sulfuric acid per gallon of oil and neutralizing and washing the neutralized oil with alcohol as in the treatment of U. S. P. white oils above described. White mineral oils which have been so treated that they will not pass the U. S. P. acid test will hereinafter be referred to as technical white oils.

It is the primary object of the present inventionto provide white mineral oils which are highly resistant to oxidation. It is another object of the present invention to provide a technical white oil which is highly resistant to oxidation and which when added in small amounts to other substances will render them resistant to oxida-' tion.

We have found that technical white oils having a sulfur content of from about 0.01% to about 0.1% processed from certain crudes, in particular high sulfur crudes having a sulfur content of white oil containing no technical white oil from about 0.5% to about 2.5%, are resistant to oxidation to a degree heretofore unknown and unexpected. Whereas the ordinary technical white oils have an averageRogers stability life test 1 (hereinafter described) "of about 40 hours, we 5 have found that the technical white oils processed from high sulfur crudes in the manner herein described have Rogers stability life tests of about 500 hours to more than 3600 hours.

Exemplary of our invention butnot limitative thereof, a distillate obtained from Winkler crude oil, which crude oil has a sulfur content of about 1.5%, when treated with about 5 lbs. of 104 sulfuric acid to give a technical white oil of about 30+ Saybolt color and a Saybolt viscosity of about '75 seconds at F. and a sulfur content of from about 0.02% to about 0.04%, has 2. Rogers stability life in excess of 3640 hours. The Rogers stability life test (as described in detail in Ind. 8;

Eng. Chem., vol. 19, page 308, 1927) is an index of the oxidation resistance of the oil. The average Rogers stability life (time to develop an acidity equivalent to 1 mg. KOI-I per gram of oil) of the ordinary technical white oil is about 40 hours.

- Wehave found that U. S. P'. white oils can be made highly resistant to oxidation by the addition of from about 0.05% to about 5% of a technical white oil which will not pass the U. S. P. acid test and particularly technical white oils from high sulfur crudes. The oxidation stability of U. S. P. white oils containing up to about 2% of a technical white oil from a high sulfur crude isabout 7500% greater than the same U. S. P.

a high sulfur crude. v 1

We have found that up to about 2% of these technical white oils from high sulfur'crudes may be added to U. S. P. white oils and still enable the white oils to pass a U. S. P. acid test. The effect of up to 2% of technical white'oil from high sulfur crude on the U. S. P. acid test is illustrated by the following table.

Table 1 '45 To. s. P. acid test-N. P. A.

colors Oil