US3294501A

US3294501A - Corrosion inhibitors for gasolines

Info

Publication number: US3294501A
Application number: US411146A
Authority: US
Inventors: Fred K Kawahara
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1964-11-13
Filing date: 1964-11-13
Publication date: 1966-12-27
Anticipated expiration: 1983-12-27

Description

United States Patent Ofi ice 3,294,501 Patented Dec. 27, 1966 3,294,501 CORROSION INHIBITORS FOR GASOLINES Fred'K. Kawahara, Park Forest, 111., assignor to Standard Oil Company, Chicago, 11]., a corporation of Indiana No Drawing. Filed Nov. 13, 1964, Ser. No. 411,146

1 Claim. (Cl. 44-71) V This is a continuation-in-part of US. patent application Ser. No. 234,557, now abandoned.

This invention relates to corrosion inhibitors for gasolines. More particularly it relates to the use of certain corrosion inhibitors for gasolines which contain tetraaIkyl-lead and a benzoic-acid or a hexahydrobenZoic-acid type lead appreciator.

For the most part, motor gasolines that are marketed in this country contain tetra-alkyl lead compounds such as tetramethyl or tetraethyl lead to upgrade their octane ratings. Recently, it has been found that certain organic compounds possess the unusual feature of enhancing the effectiveness of tetra-alkyl lead compounds. Two such compounds are benzoic acid and hexahydrobenzoic acid (i.e., cyclohexane carboxylic acid). This phenomenon of enhancing the effectiveness of tetra-alkyl lead compounds is termed lead appreciation and is currently receiving scientific as well as commercial attention.

Both benzoic acid and hexahydrobenzoic acid are very corrosive with respect to several metals, particularly when in contact with moisture. Gasolines containing either of these compounds are particularly corrosive toward zinc or zinc alloys. Both zinc and zinc alloys are used extensively in fuel pumps, carburetors and other diecast parts of automative and aviation engines.

It has now been discovered pursuant to the invention that the corrosiveness toward zinc and zinc alloys of gasolines containing either benzoic acid or hexahydro- 'benzoic acid as a lead appreciator may be substantially inhibited by incorporating into the gasoline a small amount of one or more of the following additives:

Picric acid 3;5 dintrosalicyclic acid S-nitrosalicyclic acid 1-hydroxy-2-naphthoic acid 3-hydroxy-2-naphthoic acid 2,4,5-trihydroxy =butyrophenone 5 ,5 '-methylene disalicyclic acid 2,4-'dinitrophenol It has been found that the effectiveness of the foregoing inhibitors may be considerably enhanced, in certain cases, by utilizing a combination of inhibitors, as will be shown presently. I

An additional discovery associated with the present invention is that the effectiveness of the foregoing inhibitors may be enhanced even further by adding to the inhibited gasoline a small amount of trihydroxy decanophenone, which is, by itself an ineffective corrosion inhibitor. It has been demonstrated also that many compounds which may be suggested by the prior art as inhibiting ferrousmetal corrosion and which are close analogs of the inventive additives fail to exhibit any substantial degree.

of inhibition of corrsion of zinc in the presence of benzoic by the results from tests made with such compounds as 2,4-dihydroxy benzoic acid, p-hydroxy benzoic acid, salicyclic acid, beta-naphthoic acid, Z-hydroxy stearic acid, dl-mandelic acid and citrimic acid.

The various tests employed in this series of experiments, as well as those reported later, involved the following procedure. For each test, 100 ml. of leaded gasoline were poured into a tall-form bottle. In some of these tests, the leaded gasoline contained no other substances. In others, the leaded gasoline contained 02% hexahydrobenzoic acid; and still in others, the leaded gasoline contained both hexahydrobenzoic acid and an anti-corrosion agent.

A weighted strip of metal was then immersed in each gasoline sample. After a; particular strip had been immersed for 30 minutes, 10 ml. of water were added and the bottle was rolled for one minute. After three days of immersion, each metal strip was removed, scrubbed,

' and washed to removed corrosion products and reweighed. The loss in weight was taken as a measure of effectiveness of the particular corrosion inhibitor. The results of this series of tests, which used strips of zinc metal and anti-corrosion agents suggested by the prior art, are reported in Table I below:

TABLE I Zinc Test Gasoline Composition Ifiss,

Leaded 2a saline As in- Test 1 plus 0.2% cyclohexane carboxylic acid- As in Test 2plus 2,4-dihydroxybenzoic acid (30 PIB As in Test 2 plus p-hydroxybenzoic acid (30 PTB As in Test 2 plus alicyclic acid (30 PTB Leaded a saline As in Test 6 plus 0.2% cyclohexane carboxylic acid As in Test 7 plus 2-hydroxy stearieacid (30 PTB As in Test 7 plus dl-mandelie acid (30 PTB Leaded gasoline As in Test 10 plus 0.2% cyclohexane carboxylic acid.

As in Test 11 plus citrimic acid (30 PTB 1 Concentration of additive in pounds per thousand barrels of gasoline.

The results of Tests 2, 7 and 11 demonstrate that hexahydrobenzoic acid, i.e., cyclohexane carboxylic acid, is very corrosive toward zinc. The results of Tests 3, 4 and 5 indicate that 2,4-dihydroxybenzoic acid, p-hydroxybenzoic acid and salicyclic acid, individually, did not appreciably reduce the corrosive action of the cyclohexane carboxylic acid on the zinc. Furthermore, the results of Tests 8, 9 and 12 indicatethat 2-hydroxy stearic acid, dl-mandelic acid and citrimic acid, individually, did not reduce the corrosiveness of the cyclohexane carboxylic acid toward zinc.

These results establish that anti-corrosion inhibitors of the six types suggested by the prior art do not inhibit the corrosion of zinc resulting from the presence of cyclohexane carboxylic acid (hexahydrobenzoic acid).

The quantities of the inventive additives that are incorporated into gasolines for internal combustion engines are not crucial. These quantities depend upon the amount of the benzoic acid or hexahydrobenzoic acid (cyclohexane carboxylic acid) that is present, the service conditions of storage and use, the nature of the inhibitor, and other similar factors. It has been found that excellent corrosion inhibitionis obtained at additive concentrations of as little as 30 pounds of additive per thousand barrels of gasoline (42 gallons per barrel), although this TABLE II amount may be increased or decreased as a matter of pref- Zinc Loss, Mg" ercnce. Quantities as little as 0.5 pound per thousand H Alterbarrels of gasoline, or even less, are effective, while quan- 5 Test Gasolme Composltlon tities of as much as 100 pounds per thousand barrels, or 3 Days 5 Days more, may be used in a particularly serious situation.

The other constituents of the gasoline will depend upon Leaded gasoline the manufacturers specifications and the consumers refix: f1???tiifil gfifg fifijifigigii lfi 19572213 32's quirements. Ordinarily, the gasoline is predominantly a tyrophenone 0 PTB hydrocarbon, having paraffin, naphthene, olefin and aroti tit t It tai a t tra a1ky1 l ad at 3 Concentration of additiveinpounds per thousand barrels of gasoline. concentration ordinarily within the range of 0.5 to about Th lt f T t 14 how th corrosive action of the 6 Cubic centimeters P gallon, dePehdihg 1111011 market benzoic acid toward zinc. The results from Test requirements It also y contain either behzoic acid 15 show the inhibition of such corrosion by the use of 2,4,5- or hexahydrobenzoic acid, advantageously in the freetrihydroxy butyrophenone, acid form, although derivatives such as the methyl In the second series of tests, hexahydrobenzoic acid other gasoline-soluble esters may be used. The amount (cyclohexane b li id was used as h lead of the benzoic acid or hexahydrobenzoic acid mayrange predator, A number of organic compounds was used from as iittie as 0-005 Weight Percent to about Weight to inhibit the corrosive effect of the lead appreciator on Percent As Was noted above, this q y is not Critical zinc. In addition, various combinations of these inhibiahd y be greater of smaller than the foregoing range tors were employed. In general, the concentration of an for as much as all Order Of magnitude, if this is quired. inhibitor, when used alone, was 30 pounds of the inhibitor The inventive additives were evaluated in a number of r 1000 barrel of the gasoline, In the case of the use tests employing the simple laboratory tests discussed of multiple inhibitors, the total quantity of the inhibitors above. In some of these tests, the corrosive action of did not exceed pounds per 1000 barrels. Equal porhEXahYdIOhBHZOiC acid, as inhibited y selected tions of the inhibitors were employed; for example, in pounds, was determined with iron and copper strips, as Test 29 corrosive inhibition of the zinc was brought about well as zinc strips. In each case the metal strips were of by the use of 15 pounds of 3-hydroxy-2-naphthoic acid uniform size, about 2 /2 inches long by /2 inch wide. 30 per 1000 barrels of gasoline and 15 pounds of 2,3,4-tri- Each zinc strip weighed approximately 1.5 gr.; each hydroxy decanophenone per 1000 barrels of gasoline, iron strip weighed about 2.4 gr.; and each copper strip, while in Test 36 corrosion inhibition resulted from the about 3.7 gr. use of 10 pounds of picric acid per 1000 barrels of gaso- In the first series of tests, benzoic acid was used as the line, 10 pounds of S-nitrosalicylic acid per 1000 barrels lead appreciator and zinc strips were employed. The re- 35 of gasoline and 10 pounds of 3,5-dinitrosalicylic acid per sultts from the tests of this series are presented in 1000 barrels of gasoline. The results of the tests made Table II. in this series are presented in Tables III and 1V.

TABLE III Concen Zine Loss Aiter Specified N 0. 01 Days, Mg. Test Gasoline Composition tration,

PTBI

Leaded gasoline 0.5 0 3-1 4 0. 5-2.9 2.3 0.0 0.3 0.2 Leaded gasoline and 0.2% hexahydrobenzoic acid 29. 6-34. 1 30. 8 31. 1-31. 8 34. 2 42. 3 42.1

As in Test 17 plus picric acid As in Test 17 plus 3,5-dinitrosalicylic acid.

As in Test 17 plus 5-nitrosalicylic acid As in Test 17 plus l-hydroxy-Z-naphthoic aci As i3 Test 17 plus 3-hydroxy-2-naphthoie acid As in Test 17 plus 5,5-n1ethylene disalicylic aci 30 7. 1 As in Test 17 plus 4-cthoxy-2-hydroxybenzoic aci 3O 9. 2 As in Test 17 plus 2,4-dinitrophenol 30 5.1 As in Test 17 plus 3,5-dinitrosalicylic acid and 15 3-hydr0xy-2-naphthoic acid. 15 2. 2 2. 3

1 Concentration of additives in pounds per thousand barrels of gasoline.

TABLE IV Zinc Loss After Specified No. Concen- Days, Mg. Test Gasoline Composition tlnaltion, 1

28 As in Test 17 plus 2,3,4-trihydroxy decanoplienone 30 23. 0 29 As in Test 17 plus 3-hydroXy-2naphthoic acid and 15 O 7 5 2 3 3 4 7 2,3,4-trihydroxy decanophenone. 15 30 As in Test 17 plus 3-liydroxy-2-naphthoic acid and 7. 5 1 1 19 0 2,3,4-trihydroxy decanophenone. 7. 5 31 As in Test 17 plus picric acid and 15 1 9 21 4 3 6 32 1 3-hydroxy-2-naphthoic acid. 15 32 As in Test 17 plus picrie acid and 7. 5 24 2 33 7 3-hydroxy-2-naphthoic acid. 7. 5 33 As in Test 17 plus 3,5-dinitr0salicylic acid and 15 2 2 2 3 3-hydroxy-2-naphthoic acid. 15 34 As in Test 17 plus 3,4-dinitr0sa1icylie acid and 7. 5 4 8 12 7 3-hydroxy-2-naphth0ic acid. 7. 5 35 As in Test 17 plus picric acid and 15 4 6 4 0 5-nitrosalicy in acid. 15 36 As in Test 17 plus pieric acid and 10 5-nitrosalicylic acid and 10 7 4 3,5-dinitrosalicylie acid. 10 37 As in Test 17 plus picrie acid and 10 3-hydroxy-2-naphthoie acid and 10 9 8 2,3,4-trihydroxy dccanophcnone. l0

1 Concentration of additive in pounds per thousand barrels of gasoline.

The corrosive nature of hexahydrobenzoic acid toward zinc is clearly shown by Test 17'. Examination of the reto inhibit the corrosive effect of hexahydrouenzoic acid on zinc. The results of these tests are shown in Table VI.

TABLE VI Zinc Loss, Mg. Immer- Test Gasoline Composition si0n,-

' Days Fresh Sea Water Water 48 Leaded gasoline 33 0. 4 2. 2 49 Leaded gasoline and 0.2% hexahydrobenzoic acid.-. 33 28. 4 32. 0 50 As in Test 49 plus picric acid and 3-hydroxy-2-naph- 33 0.3 1. 0

thoic acid and 2,3,4trihydroxy decanophenone. 51 Leaded gasoline 70 0. 3 15. 3 52 Leaded gasoline and 0.2% hexahydrobenzoic acid 70 43. 3 40. 2 53 As in Test 52 plus picric acid and 3-hydroxy-2-naph- 70 1. 8

them acid and 2,3,4-trihydroxy decanophenone.

sults from Tests 18-28 show the eifectiveness of the various compounds in inhibiting the corrosion of Zinc due to the presence of hexahydrobenzoic acid. Only the compound used in Test 28, 2,3,4-trihydroxy decanophenone, does not greatly reduce the corrosion. However, the use of 2,3,4-trihydroxy decanophenone in conjunction with another additive improves the corrosion inhibition due to the use of the other additive. Compare the results from Test 22 with those from Test 29. Furthermore, combinations of the various compounds seem to inhibit the corrosive efi'ect toward zinc, at least When the combinations are used in a concentration of 30 pounds of insibitors per 1000 barrels of gasoline. For example, in Test 31, the combination of picric acid and 3-hydroxy- Z-naphthoic acid in a combined concentration of 30 pounds per 1000 barrels of gasoline inhibits the corrosive action at least after 14 days of immersion. However, when the total concentration was halved, as shown in Test 32, substantial corrosion had occurred after the same period of time.

The results of the tests made with the iron and copper strips are presented in Table V.

These results indicate that although the sea water has a very corrosive effect on inc, even without the presence of the lead appreciator, the above combination of corrosion inhibitors minimized the corrosive effect on zinc when the zinc had been immersed in the solution for 70 days.

Thus it is evident that there has been provided, :according to the invention, an outstanding procedure for inhibiting the corrosiveness of gasolines which contain one or more of the following lead appreciators: benzoic acid and hexahydrobenzoic acid. While the invention has been described in conjunction with specific embodiments thereof, these are presented for illustration only. Accordingly, many alternatives, modifications and variations will be apparent to those skilled in the art. In view of the foregoing description, it is full intended to embrace all such alternatives, modifications and variations as fully within the spirit of broad scope of the appended claim.

What is claimed is:

A gasoline containing, as a lead appreciator, a member selected from the group consisting of benzoic acid and hexahydrobenzoic acid together with a first additive TABLE V Metal Loss After Specified No. of Days, Mg. Concen- Test; Gasoline Composition tration,

PTB 1 Iron Copper Leaded nasnline 0. 8 3. 7 0. 3 0. 5 Leaded gasoline and 0.2% hexahydrobenzoic acid 6. 6 6. 9 7. l 9. 4 As in Test 39 plus pieric acid 30 1. 3 As in Test 39 plus 2,3,4-trihydroxy decanophen 30 0.9 As in Test 39 plus 3-hydroxy-2-naphthoic acid and 15 3' 1 1 8 2. 7

2,3,4-trihydroxy decanophenone. l5 As in Test 39 plus 3-hydroxy-2naphthoic acid and 7. 5 4 1 6 3 2,3,4-trihydroxy decanophenone. 7. 5 As in Test 39 plus picric acid and l5 5 9 L 1 A3- hy (Ii ro b2-n1apthoic acid(.1 d 1; 5

s in es p us plcric aci an A3-hy grog2-riaphthgic agaidl 1 d d i 7.5 1 2 O 4 1 8 1 1 s in es p us 3,5- ini rosa icy ic aci an 15 A %'i%5 "i ?i t 1 1 d d 5 L3 0.6 L1 1.2

s in es p us 3,5- ini rosa icy ic aci an 3-hydroxy-2-naphtoic acid. 7.5 1 5 1 Concentration of additive in poinids per thousand barrels of gasoline.

These results demonstrate that the use of the inventive and a second additive said first additive being em 10 ed e o l a l u u 1 I o p y compounds will not detenously affect these metals. in COIIJHI'lCtlOll wlth said second additlve, said first add1- Hence, they can be used safely to inhibit the corrosive tive comprising at lea-st one member of the group consistnature of the benzoic acid or hex-ahydrobenzoie acid tomg ward zinc without seriously affecting the iron and copper Picric acid in the system. 3,5-dinitrosalicylic acid In another series of tests, sea water, as well as fresh S-nitrosalicylic id water was used. The sea water was a synthetic prepal-hydroxy-Z-na hthoic acid 5 I p a ration made according to the specification of ASTM 3-hydroxy-2-na-phtho1c acid Preparation D-665. The zinc strips were immersed in 2, ,5-tr1hydr0Xy butyrophenone the various solutions for e1ther 33 or days. A comb1 5,5 m y dlsallcyhc acld nation of picric acid, 3-hydroxy-2-naphthoic acid, and 2, 7 A- P 3,4-trihydroxy decanophenone, each in a concentration of 10 pounds per 1000 barrels of gasoline, was employed said second additive being 2,3,4-trihydroxy decanophenone, the amount of said first additive being eifective to provide inhibition of the corrosiveness of gasoline containing Water with respect to zinc, and the amount of said second additive being effective to improve said inhibition which results from the use of said first additive.

References Cited by the Examiner UNITED STATES PATENTS 2,334,158 11/1943 Von Fuchs et a1 4470 2,349,044 5/1944 Jahn 10614 DANIEL E. WYMAN, Primary Examiner. Y. H. SMITH, Assistant Examiner.