US1962435A - Gum inhibitor for cracked hydrocarbons - Google Patents

Description

Patented June 12, 1934 UNITED STATES PATENT OFFICE GUM INHIBITOR FOR CRACKED HYDROCARBONS No Drawing. Application September 26, 1930, Serial No. 484,703

6 Claims.

This invention relates to improvement in means I for the stabilization of mineral hydrocarbon products. More particularly it relates to the utilization of organic compounds as addition products for substances of the class named. The tendency of liquid hydrocarbons to discolor and to form gum, sludge and resinous substances is at present the bte noire of all persons connected with their production,-distribution and use.

Gasolines, for example, as produced by the modern cracking processes are extremely complicated mixtures comprising many constituents. The character ofthese constituents and the relative proportions of each depend upon the source of the crude petroleum and the particular cracking process employed. Ordinarily substantial percentages of unsaturated aliphatic and aromatic hydrocarbons are present. In certain instances these percentages are intentionally increased by the addition of unsaturated compounds to gasolines. Such additions may also be made to gasolines not containing unsaturated hydrocarbons. Regardless of how produced, gasolines containing these unsaturated compounds form, in -the presence of air, a series of products some of which are resinous or gummy. These gums or resins form sticky substances which deposit on the walls and bottom of the container in which the gasolines are stored and in some instances discolor the gasoline. Certain portions of the gums formed may be soluble in the gasoline but they are also objectionable because of the consequent introduction of non-volatile components into the gasoline. Exposure to sunlight causes discoloration which in some instances is accompanied by appreciable gumming.

Similar problems or disadvantages are encountered with motor benzol which is the name applied to amaterial similar to gasoline in physi. cal properties but which consists largely of aromatic or unsaturated hydrocarbon compounds. In transformer oil such as used in the electrical industry, these materials are detrimental in that a sludge tends to form in the transformer oil container and interferes with the satisfactory op:-

eration of such apparatus.

In the past it has been necessary to tolerate these disadvantages or to treat the crude products resulting from the more recent oil treating processes in some manner to remove the greater part of these unsaturated products.

This invention has for an object the inhibition or retardation of the formation of insoluble gums and resins in mineral hydrocarbons. Further objects are to prevent discoloration of the same compounds, to make possible the distribution and use of hydrocarbon motor fuels which are free from gum and to prevent gum formation in more highly cracked gasolines which would otherwise develop excessive amounts of gum and. thereby be 30 rendered unfit for ordinary use.

Still further objects are to make it possible to use as an internal combustion fuel liquid hydrocarbons such as gasoline that contain larger amounts of unsaturated compounds than commercially used at present, to produce a product of this sort at lower cost and to produce one which in certain instances possesses improved antiknockproperties. Other objects will appear hereinafter.

These objects are accomplished by the present invention whereby a member or members of the group comprising di-hydroxy naphthalenes and para-hydroxy-phenyl glycine are added in small quantities to cracked hydrocarbons. The invention Will be readily understood from a consideration of the examples which follow in which the parts are given by weight.

One of the tests used for evaluating the effectiveness of this class of compounds as stabilizers 89 or gum inhibitors is the accelerated oxygen test.

In this test twenty-five (25) cc. of motor fuel, cracked gasoline, motor benzol, or the like, treated with 0.001 to 1% of the stabilizing agent are heated at 100 C. in an atmosphere of oxygen for 3 to 6 hours. The gum formed is measured by evaporating the hydrocarbon after the oxygen test from a porcelain dish in the steam oven. The extent of gum formation during the accelerated oxygen test is a measure of the stability and gumming tendency of the fuel during the long time storage.

Example I Cracked gasoline treated with 0.02% 1:5-dihydroxy-napht halene gave 16 mg. gum per 25 co. in the accelerated oxygen gum test run for five and one-half hours. The gum formed in the same gasoline, but not stabilized, under the same conditions was mg. per 25 cc.

Example II treated. As specific examples,..=mention may be the above examples. Use may be made of higher or lower concentrations of any member of the groups of compounds disclosed above and as a result thereof greater or less inhibition of gum formation and prevention of discoloration secured depending upon the. specific agent used,

the solubility of the agent, the concentration of the agent, the nature of the material treated and the conditions under which the treatment and subsequent storage take place.

agent may vary between the limits of 0.001 to 1.0%. It will be apparent, however, that this range is not given as limiting since lesser or greater amounts may be used in specific instances within the scope of 'the invention; In

most instances no marked advantage is gained by using more than the maximum amount set out above. In any event the range given appears to be sufficient for the grades of gasoline and oils of similar characteristics now on the market.

.In' general all mineral hydrocarbons may be vided into several groups as follows:

IDihydroxynaphthalenes, such as-- (1) 1 2-dihydroxy-naphthalene (2) 1 :4-dihydroxy-naphthalene (3) 1 7-dihydroxy-naphthalene (4) 2:3-dihydroxy naphthalene The pre-l ferred actual concentration of the stabilizing II-Para-hydroxy-phenyl-glycine (5) It is to be understood that other isomers and homologues in the classes mentioned above may rbe used. In certain cases it has been found advantageous to use two or more of the specific compounds covered by this invention. It will be appreciated that the examples outlined above and the specific compounds mentioned are given merely for the purpose of illustrating and not for limiting, the invention.

Obviously this invention is of great importance in freeing internal combustion engines from the annoyance and improper functioning due to the deposition of gum in the fuel containers or fuel systems.

As many apparently widely diiferentexnbodimerits of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specific embodiments thereof except as defined in the appended claims.

We claim:

1. Motor fuel comprising cracked hydrocarbon spirits normally tending to form gum having incorporated therein a para-hydroxyphenyl-glycine in anamount sufiicient to inhibit the formation of gum therein.

2. Motor fuel comprising cracked hydrocarbon spirits normally tending to form gum having incorporated therein about 0.001 to 0.1% of a parahydroxy-phenyl-glycine.

3. Motor benzol comprising cracked hydrocarbon spirits normally tending to form gum having incorporated therein a para-hydroxy-phenylglycine in an amount sufficient to inhibit the formation of gum therein.

4. Motor benzol comprising cracked hydrocarbon spirits normally tending to form gum having incorporated therein about 0.001 to 0.1% of a para-hydroxy-phenyl-glycine.

5. Cracked gasoline normally tending to form gum having incorporated therein a para-hydroxy-phenyl-glycine in an amount suflicient to inhibit the formation of gum therein.

6. Cracked gasoline normally tending to form gum having incorporated therein about 0.001 to 0.1% of a para-hydroxy-phenyl-glycine.

FREDERICK B. DOWNING. HERBERT w. WALKER.