US3328463A - Borated-nitroalkyl-schiff base condensation products - Google Patents

Description

United States Patent 3,328,463 BORATED-NITROALKYL-SCHIFF BASE CONDENSATION PRODUCTS Richard J. Lee, Park Forest, 11]., assignor to Standard Oil Company, Chicago, 11]., a corporation of Indiana No Drawing. Filed June 30, 1964, Ser. No. 379,339 2 Claims. (Cl. 260-566) This invention relates to aliphatic ketones. More particularly it relates to nitro-ketone alkanes, their preparation, their use as intermediates in the preparation of ashless lubricant additives, and lubricants containing such additives.

The operation of the present day internal combustion engines in automobiles, delivery trucks, taxicabs, police cars, etc. in so-called stop and go city use results in severe demands for high dispersancy and detergency as well as extreme oxidation stability and protection of metal parts to rust and corrosion. This severe demand on Inbricant additives comes about by the accumulation of Water and partial combustion products in the crankcase of the engines of the foregoing vehicles. Water and many of the partial combustion products result in sludge formation which deposits on the valve train, pistons, piston rings, oil screens and filters. The partial oxidation products, when deposited on hot metal surfaces, form varnishes which impair the eiflcient operation of the engines. Many solutions to these severe performance demands of city driving conditions have been sought, but while solutions to the dispersing of water, sludge and varnish-forming materials in the lubricant oil was of paramount importance, it was also of paramount importance that the additives to accomplish the dispersing had to be thermally stable at high temperatures of continuous operation under high speed highway and expressway traveling. Also with the advent of the recommendation by internal combustion engine manufacturers of longer intervals between draining and replacement of crankcase lubricants, emphasis has also been directed at the protection of bearings and other metal parts of the internal combustion engines against corrosion, rust and wear. To further complicate the problems of formulating crankcase lubricants for the increasingly severe service demanded by the improved internal combustion engines, there was the always present problem of compatibility of the other additives such as the anti-wear, anti-corrosion, anti-rust and anti-oxidation additives. By adjustment of ratios of various additive materials, compatibility could be achieved at the sacrifice of bearing wear or bearing corrosion, rust inhibition and even oxidation stability.

A new method has been discovered for the preparation of nitro-ketones from alkenes, which ketones are valuable intermediates in the preparation of oil-soluble derivatives that are useful as ashless lubricant additives.

In accordance with the present invention, an alkene is nitrated with nitrogen tetroxide under non-oxidizing conditions to form the corresponding nitro-nitrito alkane. The nitro-nitrito alkane is then hydrolyzed under alkaline conditions in the presence of a basic material nonreactive with said alkane to the corresponding nitro-ketone alkane.

The nitration of the alkene is effected by treating the alkene under non-oxidizing conditions with nitrogen tetroxide in an inert carrier gas such as carbon dioxide or nitrogen at a temperature of from about 100 to about 250 F. until absorption of the nitrogen tetroxide ceases. The nitration is preferably conducted in an inert solvent. The amount of nitrogen tetroxide used will be about one mole per mole of unsaturation in the alkene. The nitrated product is substantially pure nit-ro-nitrito alkane.

Any olefinic material containing at least one ethylenically unsaturated site can be treated in accordance with the present invention. Monoand polyolefins can be converted to their corresponding nitro-ketones substantially quantitatively. Homopolymers of propene and butene having an average molecular weight in the range of from about 300 to 60,000 are especially useful products for the preparation of oil-soluble nitro-ketones that can be further reacted to form ashless lubricant additives.

The alkaline hydrolysis of the nitro-nitrito alkane can be effected by the addition of a concentrated aqueous solution of basic material, non-reactive with the nitro-nitrito alkane thereto, and reacting the resultant mixture at reflux temperatures. Basic materials that can be used include quaternary ammonium hydroxides, polyamines that form quaternary ammonium hydroxides in situ such as diethylenetriamine, and inorganic bases such as barium hydroxide and calcium hydroxide. Temperatures may range from about 20 to about C. for a period of time suflicient to convert the nitrito group to the keto group. Hydrolysis is generally complete when evolution of gas ceases.

The nitro-ketone alkanes containing at least 6 carbon atoms are particularly useful for conversion to ashless lubricant additives that impart detergency to liquid lubricating oils. A particular effective class of nitro-ketone alkanes are those derived from viscous polypropene and polybutene having an average molecular weight in the range of from about 300 to about 2,000.

Reaction of the nitro-ketone alkanes with a polyamine having the formula H N(RNH) H wherein R is C alkylene and x is 1 to 8, forms a nitro-Schiifs base condensation reaction product. Illustration of the polyamines are ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, propylene diamine, butylene diamine, etc. The condensation of the nitro-ketone alkane and polyamine is conducted at temperatures of from about 200 to 320 F. in the presence of a catalytic amount of an acid catalyst such as concentrated sulfuric acid. The molar proportion of the reactants is from about 2 to 4 moles of the alkane per mole of polyamine. The polyamine is preferably in slight excess to assure complete reaction with the keto groups in the nitro-ketone alkane.

The nitro-Schiifs base condensation product is then borated with boric acid or boric anhydride using about 3 moles equivalent boric acid per mole of basic nitrogen in the condensation product to provide nitrogen to boron ratio of about 3:1. The boration is conducted at temperatures of from about 200 to 300 F. The borated condensation reaction product is a valuable lubricating oil detergent.

Illustrative of the invention are the following examples:

EXAMPLE I A viscous polybutene having an average molecular weight of about 860 was dissolved in heptane in a 3-necked flask equipped with a stirrer and gas distributor, and reflux condenser. To this solution nitrogen tetra-oxide was introduced in carbon dioxide carrier gas at the rate of 2 cubic feet per hour at reflux temperatures, about F., for a period of 16 hours. Infrared analysis of the reaction product indicated substantially complete conversion of the polybutene polymer to the corresponding nitro-nitrito alkane.

EXAMPLE II Basic hydrolysis of a portion of the nitro-nitrito reaction product of Example I was conducted by treating said product with an equimolar amount of a concentrated aqueous solution of calcium hydroxide at reflux temperatures for 4 hours. Infrared analysis of the resultant reaction product indicated substantially complete conversion of the nitro-nitrito product to the corresponding nitro-ketone.

3 EXAMPLE III To 450 grams of the nitration product of Example I was added a concentrated aqueous solution of 25 grams of diethylenetriamine. The resultant mixture was then reacted at reflux temperature for 3 hours. The resultant reaction mixture was separated on a silica gel column and a yield of 70 percent of the corresponding pure nitroketone was obtained.

EXAMPLE IV To 3 moles of the nitro-ketone product of Example II was added /3 mole of tretraethylenepentamine and 2 ml. of concentrated sulfuric acid as catalyst. The reaction mixture was then heated at 270 F. for 12 hours. Thereafter, 200 grams of boric acid was added to the reaction mixture and the mixture heated at 300 F. for 12 hours. Analysis of the borated reaction product showed that it contained 1.27% nitrogen and 0.42% boron. Analysis of the condensation reaction product of the nitro-ketone and the amine by infrared showed the formation of the nitro-Schifis 'base reaction product.

The herein described borated reaction products are particularly suitable for use in amounts of from about 0.1 to about 10 weight percent as ashless addition agents for lubricating oils.

EXAMPLE V To a SAE 20 petroleum lubricating oil containing 1.2 weight percent of zinc dialkyldithiophosphate as an antioxidation, anti-wear additive there was added 2 weight ercent of the borated product of Example IV. The resultant lubricating oil composition was tested in the Lincoln MS Test Sequence V, to evaluate the low temperature dispersancy characteristics of the oil. The results obtained are:

Sludge 33 Varnish 38 Piston varn. 7.2 Oil ring plugging 22 Oil screen plugging 5 This example illustrates that the borated products prepared in accordance with this invention exhibit excellent low temperature disperancy in lubricating oils.

Suitable lubricating base oils are hydrocarbon oils, e.g., petroleum oils, synthetic hydrocarbon lubricating oils such as those obtained by the polymerization of hydrocarbons, and other synthetic lubricating oils such as alkylene oxide type oils, for example, the Ucon Oils, polycarboxylic acid ester-type oils such as esters of adipic acid, sebacic acid, azelaic acid, etc. and other synthetic lubricating oils.

While this invention has been described in connection with the use of the herein described additives and lubricant compositions, their use is not limited thereto but the same can be used in products other than lubricating oils, such as for example, fuel oils, insulating oils, greases, nondrying animal and vegetable oils, waxes, and asphalts.

Concentrates of a suitable oil base containing more than 10%, e.g. from about 15% to about or more, of the herein described derivatives, alone, or in combination with more than 10% of other additives, can be used for blending with other oils in proportions desired for the particular condition or use to give a finished product containing from about 0.1 to about 10 weight percent of the described derivative.

Lubricant composition containing the herein described derivatives can contain other addition agents such as for example, antioxidants, pour point depressors, V.I. improvers, etc.

I claim:

1. The oil-soluble lubricant additive which comprises the reaction product obtained by condensing an aliphatic hydrocarbon nitro-ketone containing at least 6 carbon atoms with a primary polyamine having the formula H N(RHN) H wherein R is C alkylene and x is 1 to 8 in the presence of a catalytic amount of an acid catalyst to form a reaction mixture containing the condensation product of said ketone and said amine; then borating said reaction mixture with a member of the group consisting of boric acid and boric anhydride to provide borated reaction product containing ratio of nitrogen to boron of from 1 to 4:1.

2. The additive of claim 1 wherein said nitro-ketone is derived from polybutene having a molecular Weight of about 860, said polyamine is tetraethylenepentamine, said acid catalyst is sulfuric acid, and the ratio of nitrogen boron is 3:1.

No references cited.

CHARLES B. PARKER, Primary Examiner.

ROBERT V. HINES, Assistant Examiner.

Claims (1)

1. THE OIL-SOLUBEL LUBRICANT ADDITIVE WHICH COMPRISES THE REACTION PRODUCT OBTAINED BY CONDENSING AN ALIPHATIC HYDROCARBON NITRO-KETONE CONTAINING AT LEAST 6 CARBON ATOMS WITH A PRIMARY POLYMAINE HAVING THE FORMULA H2N(RHN)XH WHEREIN R IS C2-8 ALKYLENE AND X IS 1 TO 8 IN THE PRESENCE OF A CATALYTIC AMOUNT OF AN ACID CATALYST TO FORM A RECTION MIXTURE CONTAINING THE CONDENSATION PRODUCT OF SAID KETONE AND SAID AMINE; THEN BORATING SAID REACTION MIXTURE WITH A MEMBER OF THE GROUP CONSISTING OF BORIC ACID AND BORIC ANHYDRIDE TO PROVIDE BORATED REACTION PRODUCT CONTAINING RATIO OF NITROGEN TO BORON OF FROM 1 TO 4:1.