CA1333488C - Process for overbased petroleum oxidate - Google Patents

Abstract

A method is disclosed for preparing overbased petro-leum oxidates which comprises carbonating a petroleum oxi-date in the presence of a base selected from the group consisting of alkali metal compounds and alkaline earth metal compounds. The petroleum oxidate is made by oxidiz-ing petroleum oil in the presence of a base. The over-based petroleum oxidates are useful as rust inhibitors, dispersants, detergents, friction modifiers and as a sub-strate for overbased sulfonates, phenates, and salicy-lates. The overbased sulfonates, phenates and salicylates are easily overbased and have improved storage stability and improved rust inhibition.

Description

13334~
PROCESS FOR OVERBASED PETROLEUM OXIDATE

Field of the Invention This invention relates to a method of preparing over-based petroleum oxidates. More particularly, it relates to a process for preparing an alkali or alkaline earth metal overbased petroleum oxidate by carbonating the petroleum oxidate in the presence of a solubilized alkali or alkaline earth metal compound and to the overbased petroleum oxidate prepared thereby. The overbased alkali metal or alkaline earth metal petroleum oxidate can be an overbased calcium petroleum oxidate, an overbased magne-sium petroleum oxidate, or an overbased sodium petroleum oxidate, as well as other overbased petroleum oxidates.
Ihe operation of diesel and spark ignition internal combustion engines is typically accompanied by the forma-tion of sludge, lacquer and resincus deposits which adhereto the moving engine parts and thereby reduce engine effi-ciency. In order to prevent or reduce the formation of these deposits, a wide variety of chemical additives has been developed for incorporation into lubricating oils.
These additives, which are commonly referred to as deter-gents or dispersants, have the ability to keep deposit-forming materials suspended in the oil so that the engine remains in a clean and efficient operating condition for extended periods of time. Among the many additives which have been developed for this purpose, certain alkaline earth metal salts have been found to be highly effective detergents for lubricating oils.
In addition to serving as highly efficient detergent additives for lubricating oils, alkaline earth metal salts are also excellent oxidation and corrosion inhibitors.
Further, these salts have the ability to neutralize acidic combustion products which are formed during engine opera-tion. The formation of these acidic products is a partic-ular problem during engine operation with high sulfur fuels. These acids appear to cause degradation of the lubricating oil and are corrosive to metal engine compo-nents such as bearings. If uncontrolled, the corrosion induced by acidic combustion products can cause rapid engine wear and a resulting early engine breakdown.
To further improve the ability of alkaline earth metal salt additives to neutralize acidic combustion products, these additives are commonly overbased.
Although overbased calcium and barium phenates and sulfonates, among other salts, have been widely known and used as detergents and sulfonates, overbased petroleum oxidates and the easy ability to make and use highly over-based petroleum oxidates have not been previously known.
The present invention is predicated on the discovery that petroleum oils, oxidized in the presence of an amount of a basic metal salt, such as metal hydroxides or, preferably, an amount of an overbased petroleum oxidate of the same composition as the overbased petroleum oxidate product, can be overbased by carbonation in the presence of an inorganic base. The carbonated overbased product of the petroleum oxidate can be used directly in a lubricant for-mulation as a rust inhibitor or as a lubricating oildetergent. In addition, the presence of petroleum oxidate facilitates the carbonation process in the preparation of overbased sulfonates, phenates and salicylates.
When petroleum oxidate is used as a modifier for pre-paring overbased sulfonates, it has been discovered thatthe carbonation overbasing process is faster and more eco-nomical than conventional methods. The overbased sulfo-nate product of the carbonation is more stable under conditions of prolonged heat and storage and is very clear in appearance, without any or with little haze present, thus adding to the product's market acceptance. Some-times, the overbased sulfonates' Total Base Number (TBN) is increased by using petroleum oxidate as an overbasing modifier.

I 3334~8 Description of the Prior Art The preparation of oxidized petroleum oils and their use as detergents in lubricating oils is known in the art.
U.S. Patent No. 2,779,737 to Koft discloses the prep-aration of calcium salts of oxidized petroleum oils by a process which comprises the steps of oxidizing a petroleum oil in the presence of calcium hydroxide and reacting the product thus obtained with a calcium salt selected from the group consisting of calcium chloride, calcium hypo-chlorite and a mixture of calcium chloride and calcium hydroxide in the presence of water. The oxidation step is carried out at a temperature within the range of from about 250~ to about 600P while passing air or oxygen through the reaction mixture. By reacting the oxidation product with a calcium salt, calcium content of the oxi-dized oil product is increased from about 3 equivalents of calcium in the oxidized product to about 3.35 to about 3.65 equivalents of calcium in the reacted product.
U.S. Patent No. 2,864,846 to Gragson discloses the preparation of alkaline earth salts of oxidized petroleum oils by a process which comprises the steps of oxidizing petroleum oil with air in the presence of an oxidation catalyst, preferably a P2S5-terpene reaction product, and neutralizing the treatea oil with an alkaline earth hydroxide or oxide.
U.S. Patent No. 2,895,978 to Brooks discloses a pro-cess for oxidation of petroleum oils in the presence of excess amounts of a metal hydroxide over and above that which is eventually taken up by the oil during the oxida-tion. The metal salts produced contain about 2 equiv-alents of metal per equivalent of acid-hydrogen formed during the oxidation.
U.S. Patent No. 2,975,205 to Lucki discloses a pro-cess for preparation of metal salts of oxidized petroleumoils which comprises oxidizing petroleum oil in the pres-ence of a metal hydroxide to incorporate the metal hydrox-1~33 ~ ~

ide into the oil and then reacting the product obtainedwith more metal hydroxide in the presence of water to incorporate an additional amount of metal hydroxide into the product.
U.S. Patent No. 2,978,470 to Christensen discloses a -- process for air oxidation of petroleum oils in the pres-ence of a catalyst such as potassium permanganate or potassium stearate. The oxidation is carried out until the change has a saponification number of about 100 to 150.
Accordingly, although the oxidation of petroleum cils to prepare a petroleum oxidate has been known, the prior art neither teaches nor suggests the invented process com-prising carbonation of a petroleum oxidate in the presenceof an inorganic base to produce a highly overbased petro-leum oxidate, which is useful as a detergent, dispersant and rust inhlbitor. Also, the prior art neither teaches nor suggests that petroleum oxidate as a process modifier improves overbasing processes for preparing overbased sul-fonates, phenates and salicylates useful as lubricating oil detergents and dispersants.

Summary of the Invention A process is disclosed for preparation of novel lubricant additives useful in lubricating oils and greases comprising overbased alkali metal and alkaline earth metal petroleum oxidates and for alkali metal and alkaline earth metal oxidate-modified sulfonates, phenates and salicy-lates with improved storage and heat stability.

1333~
-4a-Further according to the present invention, there is provided a process for carbonate overbasing S of an alkali or alkaline earth metal sulfonate, phenate or salicylate which comprises conducting said carbonate overbasing of the sulfonate, phenate or salicylate in the presence of a petroleum oxidate overbasing modifier, said modifier being obtained by a process comprising (a) introducing into a reaction zone a petroleum oil and a base selected from the group consisting of an alkali metal or alkaline earth metal compound to form a mixture; and (b) contacting said mixture with an oxidizing gas or compound at a temperature from about -40F to effect oxidation of said petroleum oil and reaction of said base with the oxidized oil.

Detailed Description of the Invention The invention comprises the method of overbasing an oxidized petroleum oil to produce an overbased petroleum oxidate and the products resulting from the overbasing process. The term "overbased" is applied to designate the presence of basic metal salts wherein the metal is present 1333~8 in stoichiometrically larger amounts than the organic acid radical. The petroleum oil is oxidized by an oxygen-con-taining gas or compound in the presence of a base. The presence of a base is an essential element of the oxida-tion process. The base can be insoluble, such as sodium hydroxideJ but a soluble base such as an overbased sulfo-nate is preferred. Air oxidation in the presence of an overbased petroleum oxidate of calcium, magnesium or sodium as catalyst is more preferred. Other overbased petroleum oxidates of barium, potassium and strontium can also be used. The resulting petroleum oxidate has a TBN
of about 1-10. The petroleum oxidate can be treated with inorganic base and carbonated to yield a clear, overbased oxidate of high TBN.
In another aspect of this invention, the petroleum oxidate can be used to modify well-known processes used to make overbased sulfonates and phenates. Such modification with oxidate often results in process or product improve-ments. Sodium, calcium and magnesium overbased petroleumoxidates are clear liquids useful as rust inhibitors, dis-persants, detergents and friction modifiers. Sulfonates overbased in the presence of petroleum oxidates have improved rust inhibitor properties with a low sulfonate soap content. Phenates overbased in the presence of petroleum oxidates are semi-solid and solid materials with lubricating properties as greases. Salicylates overbased in the presence of petroleum oxidates also demonstrate lubricant properties as grease materials.
A satisfactory feedstock for the invented process is that prepared from topped crude oils obtained from any source, for example, Pennsylvania, Mid-Continent, Califor-nia, East Texas, Gulf Coast, Venezuela, Borneo and Arabian crude oils. In this method, a crude oil is topped, i.e., distilled to remove therefrom more volatile and light gas oil, and then vacuum-reduced to remove heavy gas oil and light lubricating oil of the SAE-10 and 20 viscosity 1333~8 grade. The vacuum-reduced crude is then propane frac-tioned to remove additional heavier fractions of lubricat-ing quality hydrocarbons.
Following the propane fractionation step, the over-head oil fraction is solvent-extracted with a selective solvent which will separate the paraffinic hydrocarbons from the more aromatic type hydrocarbons. This solvent extraction step for the removal of the more highly aro-matic compounds can be carried out in accordance with the concurrent or countercurrent solvent extraction techniques which are well known in the art.
The resulting solvent-extracted material, before or after the removal of the more aromatic hydrocarbons, is preferably dewaxed. The dewaxing can be carried out by any conventional method, e.g., by solvent dewaxing using propane or other known solvents and solvent mixtures such as methylethylketone or methylisobutylketone with benzene at a suitable temperature.
A preferred feed material for the oxidation reaction is a substantially saturated hydrocarbon fraction having at least 40 carbon atoms per molecule, preferably between 40 and 80 carbon atoms per molecule, a refractive index nD20 of between 1.440 and 1.520, an average molecular weight between 550 and 1300, a viscosity of between 50 and 1400 SUS at 210F, and a viscosity index, when determin-able, of between 50 and 125.
The oxidizing reaction of the petroleum feed material is accomplished in the presence of a basic catalyst by contacting the selected hydrocarbon fraction, as hereinbe-fore described, under suitable conditions of temperature and pressure with an oxidizing agent such as free oxygen, sulfur trioxide, nitrogen dioxide, nitrogen trioxide, nitrogen pentoxide, acidified chromium oxide and chro-mates, permanganates, peroxides, such as hydrogen perox-ide, and sodium peroxide, nitric acid and ozone. Any oxygen-containing material capable of releasing molecular 133~

oxygen under the conditions can be used. Air is a pre-ferred oxidizing agent from the standpoint of economy.
Generally, the oxidation reaction is carried out at a S temperature in the range from -40F to 800F. When air is used as the oxidizing agent, temperatures in the range of 100F to 800F, preferably 390F to 575F, are generally used. When nitric acid is used as the oxidation agent, temperatures ranging from room temperature up to 200F, preferably 140F to 170F, are ordinarily used.
The oxidation reaction can be carried out at sub-at-mospheric, atmospheric or super-atmospheric pressure. The reacticn is preferably carried out at a pressure of between about 10 to 100 pounds per square inch absolute depending upon the composition of the oxidizing gas.
A basic catalyst must be present during the oxidation of the petroleum feed stock. An oxidation catalyst also can be present to promote the oxidation reaction. The oxidation catalyst can be selected from the group of well-known oxidation catalysts such as oil-soluble salts and compounds containing such metals as copper, iron, cobalt, lead, zinc, cadmium, silver, manganese, chromium and vana-dlum .
Any base may be used as the basic catalyst. It can be soluble or insoluble. Typical basic catalysts includecalcium hydroxide, sodium hydroxide, overbased sodium, calcium or magnesium sulfonate, or an overbased oxidate of high TBN (one of the products of this invented process).
Powdered, insoluble catalysts such as calcium hydrox-ide are inexpensive, but the oxidate must then be filteredto remove unreacted base. In order to eliminate the need for this filtering step, it is preferred to use a homoge-neous base, for example, a high-base calcium sulfonate.
Enough base must be used so that the total mass of oil and base has a TBN of at least 2 before oxidation. There is no upper limit to the amount of homogeneous base which can 133~

be used, but economically it is undesirable to use more than 3~ of this component.
For example, if the basic catalyst is sodium hydrox-ide, calcium hydroxide, 300 TBN calcium sulfonate, 400 TBN
magnesium sulfonate, or 400 TBN sodium oxidate, the mini-- mum base levels necessary to yield a highly overbasable oxidate would be 0.14%, 0.13%, 0.67%, 0.5~, or 0.5%, respectively. Chemically, there is no upper limit for these bases, but there are practical upper limits. For the inexpensive insoluble bases such as sodium or calcium hydroxide, unreacted base must be filtered, and it is con-venient to limit the level of base to about 2-3%. For the more expensive soluble bases such as overbased sulfonates, 2-3% is always adequate and can be described as the upper practical limit. The use of very high levels of overbased sulfonate as catalyst would thwart the very usefulness of this invention, namely, a less expensive overbasing sub-strate (soap) than sulfonate.
Since the product, high-base petroleum oxidate, of the invented process is less expensive than high-base sul-fonate, it is less costly to use the high base petroleum oxidate as catalyst instead of high-base sulfonate. Homo-geneous catalysts, such as high base calcium sulfonate, have been used at levels of 1% to 3% in the base oil. The resulting petroleum oxidate has a TBN of at least 2.
Although the oxidate can have a high TBN, the upper limit should be about 12 TBN for economic reasons. Typical petroleum oxidates will have TBNs of about 5-8.
Unexpectedly, it has been found that highly overbased products [100 TBN and higher) can be made using these oxi-dates as an inexpensive substrate instead of the usual phenate, sulfonate, or salicylate. It has been discovered that these oxidates can be used to facilitate overbasing phenates and sulfonates to unexpectedly high TBNs not pre-viously considered possible by conventional methods.

133',~
g The oxidates prepared as described above can be over-based by carbonating to clear, highly alkaline products.
The exact reason as to why clear, highly alkaline products result from using petroleum oxidate as the substrate is not known, but it is believed that the alkaline salts of - Group I and Group II metals are finely dispersed by the oxidate. The products have TBNs much higher than previ-ously achieved, as taught in the prior art.
Unexpectedly, it has been found also that use of the oxidate to prepare overbased sulfonate, phenate or salicy-late products results in improved products over those pre-pared by methods taught in the prior art. For example, use of oxidate in overbasing magnesium sulfonate can improve clarity of the product.
Unexpectedly, it has also been found that use of a petroleum oxidate as the substrate in overbasing a sulfo-nate by carbonation can result in an overbased product with a low viscosity as compared with the viscosity of an overbased sulfonate prepared without use of petroleum oxi-date.
Examples of overbased sulfonates or carboxylates which can be prepared with use of a petroleum oxidate substrate are overbased aikali and alkaline earth metal salts of sulfonic acids or carboxylic acids, typically salts of sodium, potassium, lithium, calcium, magnesium, strontium or barium prepared from sodium, potassium, lithium, calcium, magnesium, strontium or barium sulfo-nates, phenates or salicylates. The sulfonic acids can be derived from petroleum sulfonic acids such as alkylbenzene sulfonic acids. Examples of carboxylic acid salts pre-pared with use of a petroleum oxidate substrate include overbased phenates, both low-base phenates of TBN of 80-180 TBN and high-base phenates of about 250 TBN, and salicylates, prepared by reacting alkali or alkaline earth metal bases with alkyl salicylic acids. TBNs of so-pre-1~3~

pared overbased salicylates can range from about 120 toabout 250.
The overbased sulfonates prepared by the process of this invention are preferably magnesium, calcium or sodium sulfonates. Magnesium sulfonates are preferably made from - alkylbenzene sulfonic acids and typically will have a TBN
of about 400 with a sulfonate soap content of about 28%.
Calcium sulfonates preferably are from alkylbenzene sul-fonic acids and typically will have TBNs ranging from300-400 with sulfonate soap contents ranging from about 20-30~. Sodium sulfonates preferably are made from a'kyl-benzene sulfonic acids and typically will have TBNs of about 400 and a soap content of about 18~. Low-base sul-fonates prepared by the process of this invention are typ-ically calcium sulfonate and preferably are made from alkylbenzene sulfonic acids. These low-base sulfonates typically will have TBNs of 15 to 40 and a soap content of abcut 40~.
The commonly employed methods for preparing the basic salts involves heatins a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate, bicarbonate or sulfide at a temperature about 50C and filtering the resulting mass. The use of a "promoter" in the neutral-ization step and the incorporation of a large excess of metal likewise is known. Examples of compounds useful as the promoter include phenolic substances such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol, and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octyl alcohol, Cellosolve, Carbitol, ethylene glycol, stearyl alcohol, and cyclohexyl alcohol, amines such as aniline, phenylenediamine, phenyl beta-naphthylamine and dodecylamine. A particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic alkaline earth metal neutralizing agent, *Trade Marks 3~
--ll--a phenolic promoter compound, and a small amount of water and carbonating the mixture at an elevated temperature such as 60-200C.
The overbasing process is carried out in the presence of an organic solvent if more fluidity is desired. Such - solvents can be benzene, toluene, xylene or raffinate, among others.
The invented process for preparation of an overbased alkali metal or alkaline earth metal petroleum oxidate additive for lubricants with detergent, dispersant, anti-rust and friction modifying properties accordingly com-prises: (a) introducing into a reaction zone a petroleum oil, (b) a base selected from the group consisting of an alkali metal compound or an alkaline earth metal compound to form a mixture, (c) contacting said mixture with an oxidizing gas or compound at a temperature from about -40F to about 800F to effect oxidation of said petroleum oil and reaction of said base with the oxidized oil, (d) optionally, filtering said mixture to separate the base-reacted oxidized oil, (e) carbonating said base-reacted oxidized oil in the presence of a base selected from the group consisting of an alkali metal compound and an alkaline earth metal compound to form a mixture com-prising water and an overbased alkali metal or alkalineearth metal petroleum oxidate, (f) optionally filtering said mixture to remove unreacted alkali metal compound or alkaline earth metal compound, and (g) stripping said overbased alkali metal or alkaline earth metal oxidate additive to remove water.
The alkali metal compound or alkaline earth metal compound for step (b) is selected from the group consist-ing of the oxides, hydroxides and carbonates of sodium, potassium, calcium, magnesium, barium and strontium.
The alkali metal compound or said alkaline earth metal compound for steps (b) and (e) also can be selected from the group consisting of oxides, hydroxides, carbo~

1~33~

nates, sulfonates, phenates, salicylates and an overbased petroleum oxidate. The alkali metal compound or alkaline earth metal compound of step (b) also can be selected from the group consisting of oxides, hydroxides and carbonates of sodium, potassium, calcium, magnesium, barium and strontium, and said alkali metal or alkaline earth metal compound of step (e) can be selected from the group con-sisting of sulfonates, phenates, salicylates, and an over-based petroleum oxidate.
As an example, the process of the instant inventionfor preparing an overbased magnesium sulfonate comprises:
a) adding t~ a suitable vessel a charge mixture of (1) about 30 to 90 parts by weight of ammonium sulfonate, (2) about 50 to 120 parts by weight of No. 100 neutral petroleum oil oxidized to petroleum oxidate, (3) about 100 to 400 parts by weight of xylene, and (4) about 25 to about 60 parts by weight of magnesium oxide wherein said magnesium oxide is added during mixing at ambient temper-ature to about reflux temperature of said charge mixture;b) heating said charge mixture to about 100F wherein from about 10 to about 35 parts by weight of methanol is added and heating is continued up to about 140F wherein about 30 to 60 parts by weight of water is added, and the resulting mixture is refluxed for up to 4 hours;
c) distilling said mixture to remove methanol, water and xylene at a temperature of up to about 225F at ambient pressure; d) cooling said mixture to about 100F and thereupon carbonating said mixture with about 35 to about 90 parts by weight of carbon dioxide at a temperature of from about 60F to about 200F until said mixture is satu-rated; e) removing magnesium oxide impurities by centri-fuge or filtration; and f) removing remaining xylene, methanol and water by distillation at a reflux temper-ature.
The following examples are illustrative of typicalembodiments of this invention and should not be considered -13- 1 33~q ~

as limltlng the scope of the invented process and composltlons.

Example I
The following example illustrates the preparation of an oxidized calcium mineral oil which can be overbased to yield oil-miscible alkaline agents.
A suitable vessel was charged with:
- 679 g Amoco Oil HX-40 - 21 9 high-base calcium sulfonate (300 TBN ) - 10 ft.3/hr. air The mixture was heated to a temperature of 400F for 4 hours. The product exhi~ited an activity of 68% on silica gel with hexane as eluent in an elution column. It needed no filtering because the basic catalyst was solu-ble. It had a TBN of 7.

Example II
In the procedure of Example I, a sodium oxidate was prepared. A suitable vessel was charged with:
- 980 9 Amoco Oil HX-40 - 20 9 400 TBN Sodium-Overbased Oxidate (as prepared in Example V) - 10 ft.3/hr. air The mixture was heated to a temperature of 400F for 7.5 hours. Water collected overhead was 14 9. Light oil collected in a dry ice condenser was 9 9. The product was 50% active on silica gel in an elution column using hexane as the eluent. The product needed no filtering, and it had a TBN of 6. The product could also be made using NaOH
as the basic catalyst, but then it would have to be fil-tered to remove unreacted base.
*Trade Mark 13~3~8 Example III
In the procedure of Example I, a magnesium oxidate was prepared. A suitable vessel was charged with:
2,910 9 Amoco Oil HX-40 90 g high-base magnesium sulfonate (400 TBN) 10 ft3 air/hr The mixture was heated at 395F for 4 hours. The product was 39~ active on silica gel in an elution column, using hexane as the eluent. The product was clear without filtration and had a T~N of 9.

Example IV
The product from Example I was overbased with calcium as follows:
To a 2-liter, 3-neck round bottom flask fitted with a heating mantle, reflux condenser, stirrer and dropping funnel there was added 100 ml calcium oxidate from Exam-ple I, 300 ml xylene, and 10 grams calcium oxide. The mixture was then heated, and 5.5 grams of methanol were added when its temperature reached 38C, and 0.9 grams of water were added when its temperature reached 60C. neat-ing was continued and the resulting mixture heated at reflux (about 81C.) for 10 hours. A Dean Stark water trap was placed between the reaction flask and the reflux condenser. After cooling to 38C, the mixture was treated with gaseous carbon dioxide which was introduced below the surface of the reaction mixture at a rate of .41 liter/minute over a period of 8 minutes while the reaction mixture was maintained at a temperature of 38-46C. A total of 3.3 liters of carbon dioxide were absorbed by the reaction mixture. The mixture was then heated to 121C to remove water by way of a Dean Stark water trap. Next, 10 grams calcium oxide, 0.9 grams water and 5.5 ml methanol were added and the resulting mixture carbonated with carbon dioxide for 9 minutes. An addi-13~C~8 tional 2.0 liters of carbon dioxide were absorbed.
Finally, the mixture was cooled to 100P and filtered.
The filtrate was nitrogen-stripped at a temperature of about 360F to remove water and methanol.
The overbased calcium oxidate had a TBN of 120, a - level of calcium oxidate overbasing not previously known in the prior art. To my knowledge, use of petroleum oxi-date as the substrate for overbasing to such a high TBN
was not taught or suggested in the prior art.
Although acidic substrates such as sulfonic acids, phenols, carboxylates and other acidic compounds are widely used to make overbased products and, although it has long been known that mineral oils oxidize in the pres-i5 ence of air at high temperatures, it has not been previ-ously known that mineral oil can be oxidized to make clear substrates which can be overbased to make highly (e.g., TBNs 100-500) alkaline agents suitable as rust inhibitors or detergents.
Example V
The petroleum oxidate from Example II was overbased with sodium as follows: To a 2-liter, 3-neck round bottom flask fitted with a heating mantle, reflux condenser, stirrer and dropping funnel there was added 100 grams petroleum oxidate from Example II, 200 ml xylene and 370 grams of 20% NaOH in methanol. The mixture was stirred and heated to about 225F, removing and condensing the volatiies coming off as overhead. Then 16.8 liters of carbon dioxide were introduced into the mixture at a rate of 0.6 l/minute at a temperature of 225F. Carbonation was then stopped, and the mixture was cooled to 100F and filtered. The filtrate was then heated to about 360F and nitrogen-stripped for a period of about 1 hour to remove water and xylene. The resulting product was a clear, amber viscous fluid and had a TBN of 413. To my know-ledge, an overbased sodium oxidate with a high TBN has not 1333~

been previously known, and the prior art does not suggest the possibility.

Example VI
Petroleum oxidate from Example III was overbased with - magnesium as follows: To a 2-liter, 3-neck round bottom flash fitted with a heating mantle, reflux condenser, stirrer and dropping funnel, there was added 65 grams of magnesium petroleum oxidate from Example III, 100 grams xylene, 20 srams magnesium oxide and 25 ml methanol. The mixture was refluxed at a temperature of about 180F for a period of about one minute. Water, 40 ml, was added and the mixture was again refluxed at a temperature of about 220F for about one hour. The mixture was then nitrogen-stripped at a temperature of about 280F for a period of about 20 minutes to remove methanol which also removed some water. The mixture was cooled to about 120F and 17 ml water was added. Carbon dioxide was introduced into the mixture at a rate of 0.6 l/min. for a period of about 30 minutes. Approximately 5 liters of carbon dioxide were absorbed. The mixture was cooled and filtered. The fil-trate was nitrogen-stripped at 360F to remove water, xylene and remaining methanol. The product, an overbased magnesium oxidate, was a clear amber liquid with a TBN of 147. To my knowledge, overbased magnesium oxidates of such high TBN have not been reported in the prior art.

Example VII
An overbased magnesium sulfonate oxidate was pre-pared. To a suitable vessel there was added 30 grams alkylbenzene sulfonic acid (mol-ecular weight 732), 16.1 grams SAE 20 base oil, 106.9 grams petroleum oxidate prepared as in Example III, and 350 ml xylene. After mixing and heating to 100F, ammonia gas was bubbled into the mixture to neutralize the mixture. Magnesium oxide, 37 grams, with 17 ml of methanol was then added with stir-133~8 ring at a temperature of 100F. Temperature was raised to reflux, approximately 180F, and 35 ml water was added after which the mixture was refluxed for approximately one hour. The mixture was nitrogen-stripped to a temperature of about 280 F to remove volatiles comprising principally methanol, but some water was also removed. The mixture was allowed to cool to about 120F after stripping and 33 ml water was added. Carbon dioxide was introduced into the mixture at a rate of 0.6 l/min. for a period of 25 ~,inutes. Eighteen liters of carbon dioxide were absorbed. The mixture was allowed to cool to 100F and was filtered. The filtrate was nitrogen-stripped to remove solvent and water at a temperature of 360~. The proa ;-t was a clear amber liquid, had a TB~ of 396 and contained 13.2 (wt)% sulfonate soap. The product was clear, neat and in benzene solution. Prior art does not teach or suggest the preparation of an overbased magnesium sulfonate cxidate with a TBN of 396 and a low level of soap in a clear product.

Example VIII
Formulated oils containing the additives shown in Table I were prepared and tested in a Sequence II D Test Method. This procedure uses a 1977, 350 CID (5.7 liter) Oldsmobile V-8 engine at moderate speed (1500 rpm) for 30 hours followed by a shutdown for 30 minutes and 2 hours of high speed (3600 rpm) operation. The test is run with leaded gasoline. The test measures the tendency of an oil to rust or corrode the valve train. After the run, the engine is disassembled and the condition of the valve train is visually measured by trained operators against a standard of 1 to 10. A 10 is no rust. The high-base mag-nesium sulfonate oxidate prepared in Example VII was the additive used. The control was a commercially available magnesium sulfonate supplied by Amoco Petroleum Additives *Trade Mark 1333~

Company, Clayton, Missouri. The sulfonate oxidate per-formed well in the II D test.

Table I
Ex. VII
Mg ControlSulfonate Formulation (wt)%
Base Oil, 20 SAE 83.73 83.73 V.I. Im?rover 10.60 10.60 400 TBN Mg Sulfonate 1.00 0 400 TBN Mg S~lfonate Oxidate 0 1.00 Other Additives 4.67 4.67 100 . O 100 . O
II ~ Test Average Rust 8.07 8.73 Example IX
In this example, oxidate is used to facilitate the carbonation process during overbasing to produce a 400 TBN
magnesiu;~ sulfonate. The overbasing process was similar to that in Example VII, except for the amounts of raw materials charged. The carbonation proceeded much more smoothly in the run in which mineral oil was replaced by oxidate.

Run 145A: 90 9 sulfonic acid blend 63 g Amoco Oil SX-5 mineral oil Carbonation: 16 1 absorbed in 75 min, with CO2 supplied at 0.75 l/min Run 147A: 90 9 sulfonic acid blend 63 9 oxidate prepared in the method of Example III

1~33~88 Carbonation: 19 1 absorbed in only 35 min, with CO2 supplied at 0.75 l/min Example X
Overbased alkali metal and alkaline earth metal sul-fonates, phenates and salicylates, prepared wherein the substrate is a petroleum oxidate, demonstrate improved properties such as less haze.
The runs from Example IX provide an example of better solubility (less haze) in overbased sulfonates modified with oxidate.
Run 145A, control run: Haze in hexane = N
Run 1~7A, oxidate modified: Haze in hexane = F
Haze in hexane is defined as the haze of a solution con-sisting of 5% test sulfonate and 95% hexane, as measured on an Amoco Hazeometer. Range of haze values is from A
(clearest) to N (haziest).

Example XI
The influence of oxidate in modifying the carbonation process can control the viscosity of the final overbased products. The viscosity effect, accordingly, can be con-trolled, depending upon the type of product that is desired. The oxidate effect in Run 147A from Example IX
controls the viscosity of the product to produce an oil additive for which a low viscosity is desired. The vis-cosity of the control, Run 145A from Example IX, was veryhigh.
Run 145A, control run: 9,733 cSt at 100C
Run 147A, oxidate-modified: 85 cSt at 100C

Example XII
In some sulfonate overbasing processes, the presence of oxidate increases the efficiency with which the avail-~3~3~8 able metal is carbonated and incorporated into ~he prod-uct. An example is the overbasing of calcium sulfonate by the following process.
The following runs were made in a suitable vessel.
Runs 160-1 and 160-2 were controls. Run 160-3 was modi-fied by using calcium oxidate, as produced in Example I, to replace the SX-5 oil. Run 160-3 utilized over 30% more lime than controls 160-1 and 160-2.
Run 160-1, control run 1) 64.3 9 ammonium sulfonate, 56% soap, 644 MW
108.8 g Amoco SX-S mineral oil 400 ml xylene 2) blow with ammonia 3) add 65 g CaO, 6 ml water, 35.4 ml methanol;
carbonate at 115-125F

4) add 24 g CaO, 2.2 ml water, 2.4 ml methanol;
carbonate at 115-125F

5) repeat step 4 6) strip to 195F, cool to 190 F, add 4 ml water, stir 15 min 7) strip to 260F, filter, strip to 360F

Results: 31.3 liters of CO2 absorbed:
TBN = 331 Lime utilized = 36%
Control Run 160-2, repeat of Run 160-1 TBN = 334 Lime utilized = 37%

Run 160-3, oxidate-modified 34.4 1 CO2 absorbed TBN = 408 - Lime utilized = 49%

The TBN of the oxidate-modified sulfonate, 408, was approximately 22% greater than the TBN of the control sul-fonate, 334, demonstrating the increased efficiency of carbonating the oxidate-modified product.

Claims (4)

1. A process for carbonate overbasing of an alkali or alkaline earth metal sulfonate, phenate or salicylate which comprises conducting said carbonateoverbasing of the sulfonate, phenate or salicylate in the presence of a petroleum oxidate overbasing modifier, said modifier being obtained by a process comprising:
(a) introducing into a reaction zone a petroleum oil and a base selected from the group consisting of an alkali metal or alkaline earth metal compound toform a mixture; and (b) contacting said mixture with an oxidizing gas or compound at a temperature from about -40°F to about 800°F to effect oxidation of said petroleum oil and reaction of said base with the oxidized oil.

2. The overbased alkali or alkaline earth metal sulfonate, phenate or salicylate prepared by the process set forth in Claim 1.

3. The overbased sodium, magnesium or calcium sulfonate prepared by the process of Claim 1.

4. The overbased sodium, magnesium or calcium phenate prepared by the process of Claim 1.