US2382818A - Corrosion prevention - Google Patents

Description

Patented Aug. 14, 1945 CORROSION PREVENTIO Herbert D. Rhodes and Roger W. Watson, Chicago, 111., asslgnors to Standard Oil Company, Chicago, lill., a corporation of Indiana No Drawing. Application December 21, 1942, Serial No. 469,702

13 Claims. 101. 25241) The present invention relates to compositions possessing corrosion or rusting preventive properties. More particularly the invention relates to the use of certain corrosion or rust inhibitors in compositions containing predominately hydrocarbon or non-hydrocarbon materials, in connection with the use of suchcompositions in systems employing water or steam, or which may become contaminated with water or steam.

In various industrial equipment in which water or steam is used or which may become contaminated with water or steam during service, rusting or corrosion of themetal parts, particularly the ferrous metal parts, is encountered causing material damage to such equipment. For example, in the operation of steam turbines rusting or corrosion of the metal parts of such systems is a serious problem and hence the prevention or inhibition oi such corrosion or rusting is highly important.

It is, therefore, an object of the present invention to provide compositions which will effectively inhibit or prevent the rusting or corrosion of metal parts of equipment which come in contact with water or steam. It is another object of the present invention to provide an oil composition which will effectively inhibit or prevent rusting or corrosion in systems in which oil is brought in contact with water or steam. Another object of the invention is to provide means of preventing rusting or corrosion to metal parts of equipment in which water or steam is used or which may become contaminated with water or steam. Still another object of the invention is to provide a lubricant composition which effectively inhibits or amounts for example, from about 0.001% to about 0.5% and preferably from about 0.005% to about 0.1% ota hydroxylamine or an organic salt of hydroxylamine having the following representative formulae:

N 8H R t and o R"C ONRt OH in which R and R are substltuents selected from the group consisting of hydrogen, avhydrocarbon substituent and an ester residue and R" and R are substituentsselected from the group consisting of hydrogen and a hydrocarbon substituent. When R, R, R" and R' are hydrocarbon substituents such as aliphatic radicals, (i. e. alkyl and alicyclic radicals), aryl radicals, alkaryl radicals, arylalkyl radicals, etc., they may bethe same or different substituents, and are preferably of sufficient size to render the compound oil soluble, for example, a long chain parafiinic hydrocarbon. Examples of specific compounds of the above named classes are the following:

N lauryl hydroxylamine Naphthenic acid salt of hydroxylamine Wax substituted hydroxylamine Methyl naphthenate substituted hydroxylamine N butyl hydroxylamine Octyl hydroxylamine Cetyl hydroxylamine,

Lauryl hydroxylamine salt degree corrosion or rust inhibiting properties all or them are not necessarily equivalent in.i;heir effectiveness.

We are aware that hydroxylamines hav been used in lubricants to impart extreme pressure properties thereto. For example, U. 8; Patent 2,066,173 discloses the use of hydroxylamines in combination with various nitro aromatic compounds to impart extreme pressure properties to lubricants and to retard wearing and seizure of bearing surfaces. The present invention is not concerned with the lubricating properties of lubricating compositions but is concerned with the inhibition of rusting or corrosion of metal surfaces which come in contact with water. Our invention is particularly adapted to equipment or systems in which a lubricant and an aqueous material are employed, or in systems employing a lubricant in which contamination by water may be encountered. In such systems rusting is prevented or inhibited by employing a lubricant containing small amounts of a hydroxylamine or an organic salt of hydroxylamine of the type above described. For example, in the operation of steam turbines rusting or corrosion of those portions of the equipment which come in contact with water or moisture is substantially prevented or inhibited by employing a turbine oil to which has been added a small amount of a hydroxylamine or an organic salt of a hydroxylamine. 1

For the purpose of exemplifying our invention, th same will be described as applied to steam turbine lubrication, for which highly refined oils having Saybolt Universal viscosities at 100 F. of from about 125 seconds to about 350 seconds are employed, although it is to be understood that the invention is not limited thereto. With the advent of drastic refining treatments to produce more highly refined turbine oils having improved sludging resistant and emulsiflcation properties, the desirable components of oils responsible for the wetting and therefore rust-inhibiting qualities of the oil were, however, removed by these refining methods and the stable oils produced became inferior with respect to rust-inhibiting qualities. In steam turbines, rusting is usually encountered in the upper portions of oil reservoirs, and other parts of the system caused by droplets of water coming in contact with the steel surfaces which have been covered by the oil and displacing it. An oil will provide adequate protection against this rusting only if it wets the steel surfaces preferentially as compared with water. In the presence of oils which provide no protection coating, the steel surfaces are attacked by water with the formation of ferric oxide and black magnetic oxide. As the rusting progresses these oxides scale oil and may be carried in suspension in the oil, often scoring bearings, plugging oil lines and often causing faulty operation or sticking of delicate governor parts. The need for non-rusting turbine oils is therefore great.

In accordance with the present invention the addition of small amounts of hydroxylamines or organic salts thereof to turbine oils eflectively inhibits rusting of the type above described. The rust-inhibiting characteristic of turbine oils containing these additives is demonstrated by the following test: Three hundred cubic centimeters of the oil to be tested are placed in a 400 cc. lipless glass beaker and heated to about 140 F. in an oil bath and the oil stirred with a stirrer maintained at about 750 R. P. M. When the temperature of the oil sample reaches about 140 F. a cleaned test strip of cold-rolled steel is Billspended in the oil and stirring continued for 30 minutes to insure complete wetting of the steel specimen. Thirty cubic centimeters of distilled water are then carefully added by pouring it down the side of the beaker, and stirring continued for 48 hours. At the end of this period the specimen is removed from th beaker, washed with naphtha and visually inspected for the presence of rust. The method of carrying out this test is fully described in the ASTM Manual 1942, page 274, and identified as ASTMX mess-42 A number of oils containing varioushydroxylamines and salts of hydroxylamines were subjected to the above test, and the'following 'results Test pieces are rated numerically 1 to 5 accordin to increasing amounts of corrosion. A rating of 1 is g ven test pieces showing no rust or discoloration; a rating of i5 is iven to badly rusted test pieces resulting from tests on unin ibited oils.

To inhibit the oxidative deterioration of the oils susceptible to such deterioration small amounts of known antioxidants can be added to the oils in combination with the hydroxylamines or their organic salts, for example, catechol, tertiary butyl catechol and octyl catechol can be used. Other effective antioxidants are cresol, pyrogallol, hydroquinol, and hydroxy condensed ring compounds and their alkyl derivatives, such as beta-naphthol, octyl beta-naphthol, amyl betanaphthol, lauryl beta-naphthol, alpha-naphthol. cetyl alpha-naphthol, amyl alpha-naphthol and other alkyl derivatives of betaand alpha-naphthols. Other antioxidants such as phenyl alphanaphthylamine, diphenylamine, butyl para-aminophenol, etc., can be used. The amount of antioxidant employed will depend upon the effectiveness of the particular material used, but in general will range in quantity from about 0.001% to about 0.25%. Thus, we have found that a suitable turbine oil having a Saybolt Universal viscosity at F. of from about seconds to about 330 seconds exhibiting non-rusting properties and resistant to oxidative deterioration is onecontaining from about .0005% to about .1%

wax substituted hydroxylamine and from about 0.02% to about 0.2% of a mixture containing two parts of beta-naphthol and one part of octyl betanaphthol.

While we have described our invention by reference to its adaptability to turbine oils, it is to be understood that this is intended to be merely illustrative of the invention and not a limitation of .the scope thereof. Thus, our invention is applicable to emulsiilable soluble oils, liquid fuels, greases, and in general to compositions in connection with which the water-corrosion of the containing system is to be avoided.

We claim:

1. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water comprising an oil and a hydroxylalmine compound selected from the group consisting of a hydroxylamine having the general formula in which R and R are substituents selected from r the group consisting of hydrogen, a hydrocarbon substituent and an ester residue and a salt of hydroxylamine having the general formula rw-cf omw 'orl in which R" and R' are substituents selected from the grou consisting of hydrogen and a hydrocarbon substituent, said hydroxylamine compound being used in small but suflicient quantity to inhibit the corrosion of said metal.

2. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water, comprising an oil and an aliphatic substituted hy-,

' droxylamine having the general formula in which at least one of the R's is an aliphatic group, said aliphatic substituted hydroxylamine being used in small but suflicient quantities to inhibit the corrosion of said metal.

3. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water comprising an oil and an organic salt of hybut suillcient quantity to inhibit corrosion of said metal.

'7. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water comprising an oil and a methylnaphthenate substituted hydroxylamine in which the hydroxyl radical is attached directly to the nitrogen atom, said methylnaphthenate substituted hydroxylamine being used in small but sufiicient quantity I to inhibit the corrosion of said metal.

droxylamine in which the hydroxyl radical is attached directly to the nitrogen atom, said organic salt of hydroxylamine being used in small but suillcient quantities to inhibit the corrosion of said metal.

4. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water comprising an oil and a wax substituted hydroxylamine, having the general formula in which at least one of the R's is a wax substituent, said wax substituted hydroxylamine being used in small but sufficient quantity to inhibit the corrosion of said metal.

5. A rust inhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosion by said water comprising an oil and .a naphthenic acid salt of hydroxylamine in which the hydroxyl radical is attached directly to the nitrogen atom, said naphthenic acid salt of hydroxylamine being used in small but sufficient quantity to inhibit corrosion of said metal.

6. A rustinhibiting oil composition adapted for use in the presence of water in systems containing metal susceptible to corrosionby said water comprising an oil and a lauryl hydroxylamine having the general formula in which at least one of the R's is a lauryl group,

said lauryl hydroxylamine being used in small 8. In a system in which on and water are present and in which metal surfaces of said system are susceptible to corrosion by said water,the method of inhibiting said corrsion comprising employing in said system an oil containing a small amount of a hydroxylamine compound selected from the group consisting of hydroxylamine having the general formula in which R and R are substituents selected from the group consisting of hydrogen/a hydrocarbon and an ester residue and a salt of hydroxylamine having the general formula rw-c oNnw' on in which R" and R'" are substituents selected from the group consisting of hydrogen and a,

lip-0 in which R" and R' are substituents selected from the group consisting of hydrogen and a hydrocarbon substituent.

10. A stabilized and rust inhibiting turbine lubricant comprising a mineral oil, and in combination a small amount of an antioxidant sufllcient to inhibit the oxidation of said mineral oil and a small amount of a hydroxylamine compound selected from the group consisting of a lhydroxylamine having the general formula N-OH R! in which R and R are substituents selected from the group consisting of hydrogen, a hydrocarbon and an ester residue, and a salt of hydroxylamine having the general formula V oNal'" OH in which R" and R' are substituents selected from the group consisting of hydrogen and a hy- 4- a,eao,s1a

0.0005% to about 0.1% of a hydroxylamine in 1 the nitrogen atom. v

13. A ltabiliied and rust inhibiting turbine oil comprising a mineral oil. from about 0.001% to about 0.25% or a beta nephthol and from about 0.0005% to about 0.1% of a salt of hydroxylamine in which the hydroxyl radical is attached direct- 18 to the nitrogen atom.

' HERBERT D. RHODES.

ROGER W. WATSON.

which a hydroxyl radical u m nia directly to