US3036969A - Oil containing rust inhibiting combination of two ingredients - Google Patents

Description

rates Unite atent 3,036,969 Patented May 29, 1962 Fire of Delaware N Drawing. Filed Nov. 26, 1957, Ser. No. 608,937 6 Claims. (Cl. 252-325) The present invention is concerned with an oil containing two ingredients that in combination have surprising rust inhibiting properties. More specifically, this invention proposes the synergistic combinataion in an oil of minor amounts, under 0.2 weight percent each, of a branched alkyl mercaptoacetic acid and a non-emulsifying alkaline earth metal dialkylnaphthalene sulfonate to impart superior rust inhibition to the oil.

In brief compass, this invention proposes a lubricating composition comprising a major proportion of an oil of lubricating grade, and in the range of .005 to 1.0, e.g. 0.007 to 0.50, weight percent each of a C to C alkyl mercaptoacetic acid and an alkaline earth metal salt of a dialkylnaphthalene sulfonate, wherein each alkyl group has from 6 to 12 carbon atoms. The alkaline earth metal is preferably selected from the group of calcium and barium with the latter being most preferred, This rust inhibiting combination is particularly eflective when used in proportions of 3.0 to 0.3 parts by weight of branched alkyl mercaptoacetic acid to 1 part by weight of alkaline earth dialkylnaphthalene sulfonate.

The mercaptoacetic acid used in the present composition has a formula:

wherein R is a branched alkyl group containing in the range of 9 to 17 carbon atoms. In a preferred embodiment of this invention R is highly branched. By highly branch d is meant that the alkyl radical contains at least three forked or lateral groupings of one or more carbon atoms as side chains.

The particular naphthalene sulfonates used in this invention are characterized by the fact that in the concentrations used they do not tend to stabilize emulsions and in some cases actually act as demulsifying agents. That is, they do not promote the formation of stable emulsions as measured by the standard demulsibility test (ASTM D1401). Oils containing these naphthalene sulfonates do meet the limiting requirement for Navy turbine oils of 3 ml. maximum lacy end in 30minute as set forth in Specification MIL-L-17331A (Ships), The two alkyl groups of the alkylnaphthalene sulfonate may be located in various positions on the rings, and are branched chain radicals having from C to C carbon atoms per radical. Particularly preferred are the dinonylnaphthalene sulfonates of the type described in US. Patent 2,764,548.

The lubricating oil can be any conventional oil of lubricating grade known to the art, including animal, vegetable, synthetic and mineral oilsthe latter being preferred. Preferably the oil base has a viscosity in the range of 37 to 150 seconds, Saybolt Universal at 210 F., a flash point above 370 F., a pour point below 25 F., and a gravity in the range of 26 to 34 API.

Examples of suitable synthetic oils are diesters such as di-Z-ethyl hexyl seb'acate; complex esters such a reac' tion products of 2 parts di-2-ethyl hexanol, 2 parts dibasic acid, and one part polyethylene glycol of about 200 average molecular weight; silicone oils such as the polydimethyl siloxane Dow-Corning Fluid 200, prepared by hydrolytic condensation of dimethyldichlorosilane; phosphorus derivatives such as C Oxo diphenyl phosphate and the. like.

The composition of this invention can also contain normal lubricating oil additives in their customary proportions to impart certain desired properties. These additives are known to the art and include viscosity index irnprovers, pour point depressants, extreme pressure agents, antioxidants, antifoamants and the like.

EXAMPLE I The base oil was derived from a Mid-Continent crude by phenol extraction, dewaxing by the MEK process with methyl ethyl ketone and clay contacting.

It has the following inspections:

Sulfated ash, weight percent 0.001 Sulfur, Weight percent 0.22

The additives were C Oxo mercaptoacetic acid and barium dinonylnaphthalene sulfonate. The alkyl radicals of the mercaptoacetic acid were derived from C Oxo alcohol produced by carbonylation of tetrapropylene in the presence of a carbonyl catalyst, usually cobalt carbonyl, with carbon monoxide and hydrogen at a temperature in the range of 200 to 400 C. and at a pressure of from to 300 atmospheres. After the carbonylation stage, an aldehyde having one more carbon atom than the starting olefin is obtained, and this aldehyde is then hydrogenated at temperatures of from 750 F. and at pressures of from 100-300 atmospheres, in the presence of a hydrogenating catalyst (copper, nickel, etc.) to obtain the C Oxo alcohol. The C OX0 alcohol may be converted to C Oxo mercaptoacetic acid by reacting with hydrogen bromide to form the bromide and treating the bromide with an alkali metal mercaptan. The C OX0 mercaptan is then reacted with sodium hydroxide. Monochloro acetic acid is added to this reaction mixture to produce the C Oxo mercaptoacetic acid.

The barium dinonylnaphthalene sulfonate is prepared by alkylating naphthalene with highly branched nonenes, for example, tripropylene with a suitable catalyst, such as, hydrogen fluoride or anhydrous aluminum chloride in an anhydrous solvent containing in solution the naphthalene, Suitable solvents such as naphtha, sulfur dioxide, nitrobenzene or a mixture of benzene and nitrobenzene in the alkylation result in a high yield of dinonylnaphthalene and relative ease of recovery of the solvent. The dinonylnaphthalene is then dissolved in an organic solvent which is substantially inert in its reaction with sulfuric acid and the solution is sulfonated with oleum or sulfuric acid. Barium carbonate is reacted With the dinonylnaphthalene sulfonic acid to form the barium dinonylnaphthalene sulfonate used in this invention.

Oil solutions were made up and tested in the MILL 17331A rust test. This test is the Standard ASTM sea water rust test (ASTM D665) and was carried out after distilled water Washing of the oil sample at 90 C. for 30 minutes (as required by MIL-L-17331A (Ships)).

The results are shown in Table I.

Table I shows that a surprisingly small amount of each of the ingredients can be used in combination to give effective rust inhibition. These small amounts in com-" bination are equal or superior to substantially larger amounts of each of the components used separately.

EXAMPLE II In some lubricating oils it is desirable to use zinc dialkyl dithiophosphate as an antioxidant or extreme pressure additive. Some rust inhibitors of the free carboxylic acid type, including some very similar to the highly branched alkyl mercaptoacetic acid disclosed herein, form precipitates in the presence of zinc dialkyl dithiophosphate, giving hazy blends and a partial loss of rust protection. No such precipitate is formed by the use of the highly branched mercaptoacetic acid (C Oxo SCH COOH) shown in the table below. The table shows a comparison between branched C13H2'7SCH2COOH and a mercaptoacetic acid averaging n-C H SCH COOH, where the alkyl groups range from n-C H to H-C13H37.

Mixtnre of mercaptoacetic acids ranging from n-O HmSOOOH to n-CmH SCOOH and averaging H'OlQHflSCOOH.

?This additive is the same 0x0 mercaptoacetic acid as used in Example I.

EXAMPLE III The same base oil was used as in Example I. Samples were made up with 0.35 weight percent of a zinc dialkyl dithiophosphate (where the alkyl groups are derived from a mixture of about 25 weight percent isopropyl alcohol and about 75 weight percent methyl isobutylcarbinol) to test the effectiveness of the rust inhibitingcombination.

The results are shown in Table III.

Table III Highly Branched Ba Salt of 13 0 9 2 SCHQCOOI'I) Naphthalene MIL-Ir-I73S1A Mercaptoaeetic sulfonate Rust Test Acid (Weight (Weight percent) 1 percent) 2 0. 04 Nil Fail (2% Rust). 0. 06 Nil Fail (1% Rust).

Nil 0. Fail (10% Rust). Nil 0.10 Fail 1% Rust). Nil 0.125 Pass (N 0 Rust). 02 0. 05 Pass (No Rust).

1 This additive is the same mercaptoacetic as used in Example I. This additive is the same sulfonate as used in Example I.

Table II points out that the combination of mercaptoacetic acid and sulfonate in accordance with the present invention gives equally effective rust inhibition to oils containing zinc thiophosphate additives. The table also 5 points out that the combination permits good rust inhibition at relatively low total rust inhibitor content and with a low level of free acid present. Thus, even when an excess of the inhibitors has been added as a margin of safety, the combination gives desirable flexibility in pre- 10 paring blends to fulfill other important requirements of quality, for example, low ash and low neutralization number.

To demonstrate an interaction between rust-inhibiting components, low limiting concentrations, borderline in effectiveness, were tested experimentally. In actual serv- -.ice, however, it is desirable to use concentrations of rust inhibitors which will provide some margin of safety, concentrations which will still afford protection after some rust inhibitor has been removed as by plating out on metal surfaces or by very slow leaching of the inhibitors from the oil into water. The following examples show finished oil formulations incorporating the rust inhibitor combination of the invention in concentrations suitable for commercial service.

EXAMPLE IV A marine extreme pressure turbine oil was formulated using a parafiinic type oil derived from a Mid-Continent crude by distillation, phenol extraction, MEK dewaxing with methyl ethyl ketone and clay contacting.

This base oil had the same physical properties as shown in Example I. I

The following ingredients were added to this base oil. 0.35 weight percent of the zinc dialkyl dithiophosphate cited in Example III; 0.05 weight percent of barium dinonylnaphthalene sulfonate (as 50% concentrate in Coastal oil) prepared as in Example I; 0.03 weight percent C Oxo mercaptoacetic acid prepared as in Example 1; 0.0005 weight percent Silicone antifoam agent (350 centistokes at 25 C.).

The finished inhibited formulation had the following inspections.

Viscosity, S.U.S., at 210 F 59.3. Viscosity, S.U.S., at 100 F 397.7.

Viscosity index 104.5.

Pour point, F. 20.

Neutralization number (ASTM D974) 0.8.1.

Sea water rust test (MIL-L-17331A) Pas (no rust). Oxidation life (ASTMD943) 1000 hrs.

Emulsion test (ASTM D1401) (3 ml.

max. lacy cutt' after 25 mins.) Pass. Mineral acidity (MIL-L17331A) Neutral. Copper strip corrosion (ASTM D130) (3 hours at 212 F.) 1(a).

Conradson carbon (ASTM D189) 0.16. Sulfated ash 0.14. Tag Robinson color 13%. Mean Hertz load (VV-L-79l, 6503) 35.2 kg.

Ryder gear test (MILL17331A) 3310 lbs/inch.

Four ball wear scar (15 kg, 80 C.,

600 r.p.m., 2 hrs.) 0.27 mm.

This turbine oil is being field tested in a new 38,000 ton supertanker equipped with a 26,500 rated shaft horsepower compounded steam turbine, built by Newport News Shipbuilding & Dry Dock Company. The steam turbine is coupled to an articulated double reduction main propulsion gear set built by General Electric Company. The turbine oil has shown excellent service in this test.

EXAMPLE V A higher viscositylu-bricating oil was prepared by blending about 80 weight percent of the base oil of Exampie 1 with about 20 weight percent of a (propane) deasphalted, MEK dewaxed, phenol extracted, clay contacted residuum from a Mid-Continent crude to give a base oil having a viscosity at 210 F. of about 65 S.U.S. To this base oil was added 0.34 weight percent zinc dialkyl dithiophosphate, 0.15 Weight percent barium dinonyl naphthalene sulfonate, and 0.05 weight percent C 0X0 mercaptoacetic acid. This oil passed the ASDM D665 sea water rust test.

Similar oils of higher viscosity containing: (a) 0.05 sulfonate and 0.03 C Oxo SCH COOH or; (b) 0.10 sulfonate and 0.04 C 0x0 SCH COOH have passed the above rust test.

The following claims set forth that part of the above described invention for which patent protection is respectfully requested.

What is claimed is:

1. A non-emulsifying lubricating composition comprising a major proportion of a mineral lubricating oil and in the range of 0.005 to 1.0 Weight percent each of a branched C to C alkyl mercaptoacetic acid and an alkaline earth metal salt of C to C branched chain dialkylnaphthalene sulfonate as the sole sulfonate, the alkaline earth metal being selected from the group consisting of calcium and barium.

2. The lubricating composition of claim 1 comprising, in addition thereto, 0.05 to 2.0 weight percent of an oil soluble zinc C to C dialkyl dithiophosphate.

3. The lubricating composition according to claim 1 wherein the alkyl radical of the alkyl mercaptoacetic 6 acid is a highly branched radical having at least three branched groups.

4. The lubricating composition according to claim 1 wherein the mercaptoacetic acid is a highly branched C mercaptoacetic acid and the sulfonate is a branched chain dinonylnaphthalene sulfonate.

5. The lubricating composition according to claim 1 wherein said alkyl mercaptoacetic acid is a C Oxo mercaptoacetic acid and wherein said dialkyl naphthalene sulfonate is a barium dinonylnaphthalene sulfonate.

6. The lubricating composition according to claim 2 wherein said alkyl mercaptoacetic acid is a C Oxo mercaptoacetic acid and wherein said dialkyl naphthalene sulfonate is a barium dinonylnaphthalene sulfonate.

References Cited in the file of this.patent UNITED STATES PATENTS 2,364,284 Freuler Dec. 5, 1944 2,491,066 Wasson et a1. Dec. 13, 1949 2,693,448 Landis et al. Nov. 2, 1954 2,739,125 Myers et al Mar. 20, 1956 2,764,548 King et a1 Sept. 25, 1956 2,779,784 Sharrah Jan. 29, 1957 FOREIGN PATENTS 659,072 Great Britain Oct. 17, 1951 689,759 Great Britain Apr. 1, 1953 526,206 Canada June 12, 1956

Claims (1)

1. A NON-EMULSIFYING LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND IN THE RANGE OF 0.005 TO 1.0 WEIGHT PERCENT EACH OF A BRANCHED C9 TO C17 ALKYL MERCAPTOACETIC ACID AND AN ALKALINE EARTH SALT OF C6 TO C12 BRANCHED CHAIN DIALKYLNAPHTHALENE SULFONATE AS THE SOLE SULFONATE, THE ALKALINE EARTH METAL BEING SELECTED FROM THE GROUP CONSISTING OF CALCIUM AND BARIUM.