US 2510031 A
Description (OCR text may contain errors)
Patented May 30, 1950 METHOD; on INHIBITING vownon OF HYDROGEN; SULFIDE FROM SULFURIZED OIL LUBRICANTS nerrrqidacrr, lzbslhifieles, cam, assigno'r to socony vacuum- Oil Company, Incorporated, New York, Y=,- a corporation of-New York No Drawings Application,OctobrZD,1945, Serial No. 625,461
4 claims. 1,
inthe manufacture of ktrmepressuie liibri cants' for various purposes it is common practlce tostiI iuriZe the mineral oil stock ofto blend mmer n "on with'a sulfurized' an 'or fatsu'ch as laid on; sperm oil, hydfogenf'ated fats, etc.
In the step of sulfurization whi'cli is a direct addition of sulfur to the hatedbil; more or'less hydrogen sulfide is evolved; This'is customarily removed by air blowing; so that thEfilflSHGGPI'Odu'ct is free from objectionable odor.
Unfortunately, however, the reaction by which hydrogen sulfide is produced is often notcomp l't'ed during the manufacture of the oil, but
continues during the storage "of the product. The" dd'or thus. generated not particularly dtrimental if the Oh is used ina closedshell, as for example a gear case, but where the product is used for metal cutting, grindingpr forming the fetid odor of hydrogen sulfide is highly objectionable to the operator and is the source of many complaints. p
h I have discovered that hen anoil 'sol'uble soap of a wat'erdnsoluble, heavy metal which forms a stable sulfide is add'edto the sulfurized product,
preferably as a final step in its manufacture. and
after all free hydrogen sulfide has been blown off} the further formation of hydrogen sulfide is inhibited over extended storage p'e'riods. Apparently the inhibiting action is common to a long list'of heavy metals, includingcadmium, cop per, cobalt, iron, lead, manganese, mercury, nickel, silver, tin, and Zinc, and is indifferent to the nature of the soaps-forming organic acid with which the metal is combined, so long as the 'soap is readily oil-soluble. For reasons of economy,
However, and also because of their somewhat greater effectiveness, I' prefer 'to use the lead, copper, and cadmium soaps, and particularly the'naphthenates and the oleats of'these metals.
The effectiveness of these agents in inhibiting the release of free hydrogen "sulfide, with its production of an unpleasant odor, was demonstrated by a series of experiments in which lead naphthenate, lead oleate, copper naphthenate, copper oleate, zinc naphthenate, and the naphthenates of chromium, nickel, manganese, cadmium, iron, and cobalt were used as inhibiting agents; and (A) copper sulfate, (B) cadmium chloride, and (C) mercuric chloride as indicators.
Inmaking the tests the sulfurized compounded oils were heated and blown until free from odor and were'then divided into the-'requisite number of portions and the additives mixed in. The samples were then stored for various periods, at the end of which paper strips spotted with solutions of the three indicators were introduced into the vapor space above the oil and allowed to remain for five minutes (in the case of Test s for 40 hours). The varying sensitivities of these indicators is shown by the following table:'
TABLE' '1' Sensitivity of "indicators Classification 7 Vol; Per cent Has Reactions by $815115? of in Vapor More than 0.002%. 0 n .9 6
Lesslthan 0.001% Undetermined.
TABLE II M ine'raZ =0zl with 50 sulfurized lard oil '(1 5%18') [Lead maphthenate inhibitor] Percent Storage, Period Lead added 49 Days 76 Days 203 Days 329 Days 522Days i/idiu m SIight Slight.
Slight .sdo Ntmp None..- None.
fin .Lj'ln TABLE III sulfurizedlminemltloil(0.7 added S) with 6.4% sulfurized lard'oz'l (15% S) [Lead naphthenate inhibitor] Storage Period Trcent LeadiAddcl" n l 3 Days 1 48 Days 274 Days.
None -Strong n N511; None None. (1 T1 1 'rln dn D0; 0.1'I';.; fin dn D0 Mineral oil wit h;% or sulfurized mineral oiZ (8% added :8)
[Head naphthenate inhibitor] StoragePeriod Percent LeadAddd 84 Da'yszonna s None Strong -Strong: 0.08..- m NnnP- Medium. 011 do 1 Slight. 0.17 None: 0 28.;. (ln 1 DOW 3 TABLE V Mineral oil with 50% sulfurized Zara, oil (15% S) Storage Period Per cent Inhibit MetalAdded 95 days 213 days 406 days Lead Naphthenate 0.056 Pb Slight--- Medium Strong.
Do 0.11 Pb do Sl1ght Medium. D 0.17 Pb None None Slight. Lead Oleate 0.026 Pb- Medium Strong Do--- 0.05 Pbht Do. 0.08 Pb (1 Strong. CopgerNaphthenate 0.016 Cu 0.05 Cu Strong. 0.017 Ou 0.03 Cu 0.05 Cu None Slight Strong. 0.016 Zn Strong Strong" 0.03 Zn Medium do 0.05 7n Jin Medium Strong.
TABLE VI Mineral ml with 50% sulfurzeed lard 012 (15% S) Per Cent Storage 141 Inhibitor etal Added Days Strong.
Do. Medium. Strong.
Do. Medium. Strong.
Do. Slight. None. Strong. Do.
Medium. Strong. Medium.
TABLE VII With Phosphorized and Sulfurized Oil 15 Days Storage With 10% Phosphorized and Sulfurized Oil Days Storage Percent Lead Added None Strong- Strong. 0.28... N None. 0.56 do Do.
The effect of these minute additions of heavy metal soaps on the extreme pressure characteristics of the lubricant is immaterial. The lead soaps, when used in greater quantity, impart extreme pressure resistance, while the effects of the other heavy metal soaps are either favorable or neutral.
The tests summarized in Tables II-VI, inclusive, show that as regards the development of free hydrogen sulfide, the lead soaps and copper and cadmium naphthen ate are substantially on a parity when the dosage is proportionate to the molecular weight of the metal, being notably effective as deodorizers. Copper oleate and the naphthenates of other heavy metals, for example, chromium, nickel, manganese, cadmium, iron, and cobalt are seen. to be also effective, though the reactions are somewhat less marked. All may be useful under given circumstances. It is additionally apparent that the particular organic acid with which any of the metals is combined appears to affect only the solubility of the soap in mineral oil, a characteristic which is prerequisite to functionality.
The tests shown in Table VII indicate that lead as lead naphthenate effectively deodorizes a phosphorized and sulfurized oil, and it is believed that other heavy metal soaps will serve similarly.
While the above tests show that a very minute quantity of the heavy metal soap suffices to inhibit the evolution of hydrogen sulfide in storage, it will be understood that much larger quantitles of the soap may be used if desired, up to the point, if any, at which the soap begins to exercise a deleterious effect on the extreme pressure-resisting properties of the lubricant.
It is further understood that I do not intend to be restricted either as to nominal dosage quantities of the heavy metal soaps hereinabove mentioned, or as to the particular solutions thereof, but rather intend to include all such usage within the spirit of my invention and the scope of the appended claims.
I claim as my invention:
1. The method of inhibiting the evolution in storage of hydrogen sulfide from lubricants compounded with sulfurized oils which consists in adding to the compounded lubricant, after removal therefrom of free hydrogen sulfide, an oilsoluble soap of a metal selected from the group consisting of lead, cadmium, copper, zinc, chromium, manganese, iron, nickel, and cobalt, in proportions of about 4 to parts by weight of said metal per thousand parts by weight of sulfur.
2. The method of inhibiting the evolution in storage of hydrogen sulfide from lubricants compounded with sulfurized oils which consists in adding to the compounded lubricant, after removal therefrom of free hydrogen sulfide, an oilsoluble soap of lead in proportions of about 4 to 75 parts by weight of lead per thousand parts by weight of sulfur.
3. The method of inhibiting the evolution in storage of hydrogen sulfide from lubricants compounded with sulfurized oils which consists in adding to the compounded lubricant, after removal therefrom of free hydrogen sulfide, an oil-soluble soap of copper in proportions of about 4 to 75 parts by weight of copper per thousand parts by weight of sulfur.
4. The method of inhibiting the evolution in storage of hydrogen sulfide from lubricants compounded with sulfurized oils which consists in adding to the compounded lubricant, after removal therefrom of free hydrogen sulfide, an oilsoluble soap of cadmium in proportions of about 4 to '75 parts by weight of cadmium per thousand parts by weight of sulfur.
BERT FOLDA, JR.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 604,515 Bragg May 24, 1898 2,242,624 Schulz May 20, 1941 2,246,281 Zimmer June 1'7, 1941 OTHER REFERENCES The Alkaline Earth and Heavy Metal Soaps,
E'lliott (1946), pages 144, 169, 201, 213, 214, 219