US2436051A

US2436051A - Lubricant

Info

Publication number: US2436051A
Application number: US551777A
Authority: US
Inventors: Lawson W Mixon
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1944-08-29
Filing date: 1944-08-29
Publication date: 1948-02-17
Anticipated expiration: 1965-02-17

Description

Pat ented Feb. 17, 1948 LUBRICANT Lawson W. Mixon, Hammond, Ind. assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application August 29, 1944, Serial No. 551,717

7 Claims. (c1. 25.2-33.6)

The present invention relates to improvements in lubricants and more particularly to lubricants containing an adjunct which imparts to the lubricants varnish inhibiting properties.

More particularly the invention relates to lubricating oil compositions adapted for use in ,internal combustion engines of the spark ignition and compression ignition types wherein under operation conditions corrosion, piston ring stick, ing, cylinder wear and varnish formation are substantially reduced.

Straight petroleum lubricants are effective within certain defined limits of engine operating conditions but when these limits are exceeded, such lubricants frequently fail to give the desired performance required of them, Since in modern engines designed to give increased performance, these limits are frequently exceeded, the use of straight hydrocarbon oils as lubricants produce undesirable conditions within the engine, thus varnish and carbon formation becomes excessive and corrosion of improved hard metal alloy type bearings is encountered.

It is ,an object of this invention to provide a lubricant which is resistant to the formation of varnish. It is another object of this invention to provide a hydrocarbon oil composition adapt- -ed for use in internal combustion engines and which is resistant to the formation of sludge, acidity and varnish and which is non-corrosive to bearing metals, particularly bearing metals of the hard metal alloy type. Other objects and advantages of this invention will become ap-,

parent as the description thereof proceeds.

I have discovered that the foregoing objects can be attained by adding to a lubricant composition containing a lubricating oil such as, for example, an animal, vegetable, marine, or a hydrocarbon oil such as a mineral or petroleum oil, a metallic salt of an organic polythiocarbonate in small but sufiicient quantities to inhibit varnish and/or sludge formation in such lubricant. Generally from about 0.05% to about Ira-(Lam in which x is an element selected from the group consisting of oxygen and sulfur. R is an organic group such as an alkyl, aryl, alkaryl, aralkyl, alicyclic or heterocyclic radical, and M represents a metal such as, for example, lithium, sodium, potassium, magnesium, calcium, strontium, barium, copper, aluminum, chromium, tin, lead, iron, cobalt, nickel, titanium, tungsten, vanadium, and zinc. The organic group may contain inorganic substituents such as oxygen, sulfur and phosphorus, Particularly efiective for the herein-described purpose are the metal salts of terpene polythiocarbonate and the metal salts of keryl polythiocarbonates. The term "keryl polythiocarbonate" denotes a substituted polythiocarbonate in which the hydrocarbon constituent is a petroleum fraction having distillation characteristics corresponding to that of a kerosene fraction.

,The metal salts of the organic polythiocarbonates can be prepared by reacting an alcoholic solution of a hydrocarbon mercaptan and caustic such as KOH with carbon disulfide. The alkali metal organic polythiocarbonate can then be treated with a polyvalent salt to obtain any desired metal salt of the organic polythiocarbonate. The preparation of these compounds is exemplifled by the following examples'which are given by way of illustration only and are not intended as limiting the scope of the invention. The zinc salt of terpene trithiocarbonate was prepared in the following manner: 108.5 grams of terpene mercaptan and 42 grams of KOH was dissolved in 500 cc. of ethyl alcohol. To this alcohol solution was added 48 grams of carbon disulfide and the mixture was stirred for about 15 minutes at a temperature of about 80 F. Upon completion of this reaction grams of zinc chloride dissolved in 100 cc. of water was added to the mixture withstirring. The zinc salt of the terpene trithiocarbonate was separated from the reaction mass as a reddish yellow oil by hexane extraction,

The zinc salt of keryl tri'thiocarbonate was prepared in the following manner: 108 grams of keryl mercaptan was dissolved in 300 cc. of ethyl alcohol. To this alcohol solution was added grams of carbon disuliide and the mixture was stirred for about 15 minutes at about F. At the end of this reaction a slight excess of zinc chloride dissolvedin water was added to the mixture with stirring. The zinc salt of the keryl trithiocarbonate was separated from the reaction mass as a reddish yellow oil by hexane extraction.

The metal salts of the organic polythiocarbonates of the type herein-described are particuhydrocarbons such as suliurized mineral oils,

sulfurized terpenes, substituted amines such as, for example, polyamino polyaryl methanes such as aminomethyl-aminodiphenyl methane, tetramethybd'iamino-diphenyi methane, diimethyl amino) dina'phthyl methane and derivatives 01 the same.

The eiiectiveness oi the metallic salts of or- 4 game polythiocarbonates in inhibiting varnish formation in internal combustion engines is 11- lustrated by the following data. These data were obtained by subjecting 0113 containing the addifail-rust agents, extreme pressure agents and the While I have described my invention with re!- erence to specific embodiments thereof, it is to be understood that the same are given merely by way of illustration and are not intended to limit the scope of the herein-described-invention except insofar as the same are defined by the appended claims.

I claim:

1. A normally liquid lubricant composition comprising a major proportion of a hydrocarbon oil and from about 0.0b% to about 10% of a zinc organo trithiocarbonate oi the group consisting of a zinc alkyl trithlocarbonate and a zinc alicyclic trithiocarbonate.

2. A normally liquid lubricant composition resistant to the formation of products of oxidative deterioration oi the type of varnish and sludge,

tives to accelerated engine tests made in the standard six cylinder spark ignition internal combustion engines operating for 60 hours at 35 B. H. I. and 3000 R. P. M. with an oil sump temperature of 285 F. At the end of the test period the engines are dismantled. inspected and given visual ratings. In this visual rating system a rating 0! 10 means that the engine had substantially the appearance or the engine at the start of the test while a rating of 1 indicates that the engine aiter'the test showed very extensive deposits of varnish and sludge. Engines having appearances between these extremes are given intermediate rating values. An engine lubricated with 'good conventional motor oil for a 60 hour period usually merits a visual rating of about 5. The data presented herein were obtained by subjecting the following oils to the foregoing tests:

Oil A.-,98.75% acid treated SAE-30 M. C. motor oil, 0.75% KOH neutralized reaction product of Past and isobutylene polymer, 0.25% suliurized mineral oil, 025% suliurized terpene.

Oil B.'Oll A+0.5% zinc terpenyl trithiocarbonate.

Oil O.-Qil A+0.5% zinc keryi trithiocarbonate.

The above data demonstrate the improvement in the overall and varnish rating due to the presence of the metallic soap oi the organic polythiocarbonate. I

The present invention also contemplates the addition 0! other additives to lubricant compositions such es, lo: example, antioxidants. pour point depressor-s, V. I. improvers, oiliness agents,

comprising a major proportion of a hydrocarbon oil normally susceptible to oxidative deterioration and in combination therewith from about 0.05 per cent to about 10 per cent of a zinc salt of an organic trithiocarbonate selected from the class consisting of an alkyl trithiocarbonate and an alicyclic trithiocarbonate and an additive exhibiting detergency properties, the latter being used in small but suiilcient quantities to inhibit the deposition or varnish and sludge on engine parts.

3. A normally liquid lubricant composition as described in claim 2 in which the additive exhibiting detergency properties is the neutralized reaction product of a phosphorus sulfide and a hydrocarbon.

4. A normally liquid lubricant composition comprising a major proportion of a hydrocarbon oil and from about 0.05% to about 10% of a zinc salt of an alkyl trithiocarbonate.

5. A normally liquid lubricant composition comprising a major proportion of a hydrocarbon oil and irom about 0.05% to about 10% of a zinc salt of an alicyclic trithiocarbonate.

6. A normally liquid lubricant composition containing a major proportion oi a hydrocarbon oil REFERENCES CITED The following references are of record in the file of this patent:

. UNITED STATES PATENTS Number Name Date 2,365,011 Rosen Dec. 12, 1944 2,289,105 McNab July 14. 1942 2,197,835 Reii! Apr. 23. 1940 2,346,155 Denison et al. Apr. 11, 1044