US2249602A - Suppression of metal catalysis - Google Patents

Description

Patented July 15, 1941 SUPPRESSION or METAL CATALYSIS Joseph A. Chenicek, Chicago, Ill., assigno'r to Universal 011 Products Company, Chicago, 111., a

corporation oi. Delaware No Drawing. Application December 28, 1939, Serial No. 311,316

12 Claims.

or.minimize oxidation reactions resulting in the formation or objectionable peroxides, gums and other deleterious oxidation products has been practiced. They are particularly useful in cracked, reformed, and polymer gasolines which contain relatively high concentrations of monoolefins and somewhat smaller concentrations of other unsaturated hydrocarbons such as diclefins.

The function of inhibitors is primarily to minimize or prevent such oxidation reactions and thus keep the motor fuel in satisfactory condition for use in internal combustion engines. They tend .to prevent losses in antiknock value which accompanies oxidation of this type of gasoline. Among the materials which have been used are various phenolic, amino, and amino-phenolic compounds as well as fractions of wood tar oil, etc. which are usually added to the gasoline in concentrations of approximately 0.0010.1%, depending upon the efiectiveness of the particular compound used and the gasoline to which it is added.

Although inhibitors are used in both treated and untreated gasolines, it is with the latter type that they find the greatest application. Treated gasolines may be defined as those which have been subjected to chemical refining processes such as sulfuric acid, fullers earth, and the like, either with or without a subsequent. sweetening treatment. Untreated gasolines may be said to be those which have received no refinement beyond possibly caustic washing and/or sweetening. The former type of gasoline is usually relatively stable and requires little or no added inhibitor, although the use of inhibitors has been practiced to supplement other refining methods. In the case of. untreatedgasolines, on the other hand,

many bf them are unstable and require thaprotectionsaifo'rded by inhibitors to prevent undue deterioration during the time they are in storage.

Practically all gasolines require some form of sweetening treatment in order to improve the odor thereof and produce a product having a negative doctor test. The sodium plumbite or doctor process, as well as the hypochlorite sweetening process have been used in the past with .onsiderable success. During recent years, the o-called copper sweetening process has been developed in which gasoline is contacted with a copper-containing reagent. As a result of the presence of relatively minor amounts of impurities in such gasolines, the sweetened gasoline usually contains relatively small amounts of copper compounds which have a catalytic efiect on oxidation reactions which may result when the gasoline comes in contact with air. Various methods have been developed for removing such copper compounds including treatment with alkalior alkaline earth-metal sulfides; and heavy metal sulfides such as zinc sulfide and the like. In some instances, however, these reagents may not be completely effective in removing the copper from the gasoline and as a consequence the gasoline may have a reduced stability and susceptibility to added gasoline gum inhibitors. Moreover gasolines come in contact with various metals in the course of refining, storing and shipping operations, and this may result in the gasoline containing minute amounts of such metals as copper, iron, cobalt, nickel and the like which are oxidation catalysts. It is with a method of pre-' venting depreciation due to the presence of such catalysts that this invention is concerned.

In one specific embodiment the present invention comprises a method for suppressing the catalytic action of heavy metal compounds which may be contained in hydrocarbon distillates such as cracked gasolines and which tend to promote the ,formation of gum therein, by adding to said gasoline-approximately 0.00010.01% of a condensation product of a mono or polyhydroxy benzaldehyde with an aminophenol, either with or without a gasoline gum inhibitor.

Compounds of this type may be represented'by the general formula:

m mo.

wherein R is a substituent group such as an hycompound of this type is ortho-hydroxy-benzalortho-aminophenol.

These compounds may be made by dissolving In some cases the compounds may be used in the gasoline without added gum inhibitors. This is particularly true when used in connection with straight-run di'stillates or cracked gasolines which have been refined to an adequate degree of stability such as by acid-treatment or other suitable methods. However these compounds are not of themselves gasoline gum inhibitors except to a minor extent, so that they do not result in a gasoline of improved stability except when metal compounds are present therein.

However, the usual method of application is to add both the suppresser and the gasoline gum inhibitor simultaneously. The resulting induction period is usually the same or slightly increased over that obtainable with the inhibitor alone in a gasoline free of metal compounds. The suppresser may be dissolved in the gasoline gum inhibitor. As a rule, smaller amounts of the sup? presser are required than of the gum inhibitor so that a relatively minor amount of the suppresser may be added to the inhibitor, say for example, less than 50% ofthe total mixture. When using inhibitors of the aminophenol type, the hydroxybenzaldehyde 1110100110110 solution can be added directly to the inhibitors Thefollowing examples are given to illustrate the usefulness of the invention, but shouldnot be construed as limiting it to the compounds shown therein.

Example 1 A cracked gasoline produced by cracking Pennsylvania. crude oil was sweetened by a copper-sweetening method and was found to contain 1 mg. of copper per. liter of gasoline. The induction period when the copper was completely 325 minutes for a copper-freesample of the gasoline plus 0.01% of the commercial inhibitor.

Example 2 To an acid-treated cracked gasoline having an induction period of 300 minutes and a-copperdish gum content of 5 mg., was added 1.5 mg.- of copper per liter of gasoline. period was reduced to -100 minutesand the cop per-dish gum content increased to 95. Addition of 0.001% of ortho-hydroxy-benzal-ortho-aminophenol to the gasoline brought the induction period to 325 minutes, the gum content to 15 mg. per 100 cc.

Example 3 A Mid-Continent gasoline containing 0.75 'mg. of copper per liter had an induction period upon the addition of a commercial gum inhibitor of 175 minutes. Upon the addition of 0.005% of orthohydroxy-benzal-meta-aminophenol, the induction period was increased to 2'75 minutes.

Another sample was treated with 2,4-dihydroxy-benzal ortho-aminophcnol and the induction period in the presence of a commercial gum inhibitor was increased to 300 minutes.

Example 4 1. A method for treating gum-forming hydrocarbon distillates containing metal compounds having a catalytic effect on gum formation, which comprises incorporating into the distillate a relatively small but suflicient quantity of an orthohydroxybenzal aminophenol to suppress said catalytic eflect of the metal compounds.

2. A method for treating gum-forming hydrocarbon distlllates containing metal compounds "having a catalytic eifect on gum formation, which comprises incorporating into the distillate a relatively small but suflicient quantity of -a -mono- 'ortho-hydroxybenzal-amlnophenol to suppress said catalytic effect of the metal compounds. I

3-. The method as defined in claim 1 further characterizedin that the suppressor of said catalytic eilect comprises ortho-hydroxybenzal-orthoaminophenol.

4. The-methodas defined in claim 1 further 0 characterized in that the suppressor of said catalytic effect comprises ortho-hydroxybenzal-metaaminophenol.

5. The method as defined in claim 1 further characterized in that the suppressor of said cate lytic effect comprises ortho-hydroxybenzal-para aminophenol. p v

6. The method as defined in claim 1 further characterized in that the suppressor of said catalytic eflect is incorporated into the distillate in V the amount 01' about 0.0001 to 0.01%.

'7. Motor fuel comprising gum-forming gasoline containing metal compounds having a catalytic effect on gum formation and additionally containing, as a suppressor of said catalytic eflect, a relatively small amount of an ortho-hydroxybenzal-amino-phenol.

8. Motor fuel comprising gum-forming gasoline containing metal compounds having a catalytic effect on gum formation and additionally containing, as a suppressor of said catalytic efl'ect, a relatively small amount of a mono-ortho -hydroxybenzal-aminophenol.

, 9. Motor fuel comprising gum-forming gasoline containing' metal compounds having a' catalytic The induction ortho-aminoph'enol effect on gum formation and additionally containing, as a suppressor of said catalytic eflfect, a

relatively small amount of ortho-hydroxybenzal- 10. Motor fuel comprising-gum-forming gasoline coiitainingmetal, compounds having a catalytic effect on g'um formation and additionally containing, as a suppressor of said catalytic effeet, a relatively small amount of orthoehydroxybenzal-meta-aminophenol.

11-. Motor fuel comprisinggum-forming gaso- -,line containing metal compounds having a catalytic efi'ect on gum formation and additionally lytic effect on gum formation and additionally containing, as a suppressor of said catalytic efcontaining, as a suppressor of said catalytic effect, feet, a relatively small amount of ortho-hydroxyabout 0.0001 to 0.01% of an ortho-hydroxybenzalbenzal-para-aminophenol. aminophenol. a

12. Motor fuel comprising gum-forming gaso- 5 JOSEPH A. CHENICEK.

line containing metal compounds havlngacata-