CA1116627A

CA1116627A - Process for preparing nitrogen and phosphorus-containing compositions

Info

Publication number: CA1116627A
Application number: CA000314181A
Authority: CA
Inventors: Bruce W. Hotten
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1977-12-08
Filing date: 1978-10-25
Publication date: 1982-01-19
Also published as: JPS5486504A; FR2411231A1; FR2411231B1; GB2010844A; DE2852205A1; NL7811873A; GB2010844B

Abstract

ABSTRACT OF THE DISCLOSURE
Amine phosphate salts or mixtures thereof with phosphoramides are prepared by reacting a triaryl phosphate with an aliphatic amine in the presence of certain boron-containing catalysts. The composition of the product depends upon the specific catalyst used. Certain products are useful as lubricating oil additives.

Description

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FIELD OF THE INVENTION
This invention relates to a process for preparing amine phosphate salts or mixtures of amine phosphate salts and phosphoramides and the products prepared by this process. This invention also relates to lubricating oil compositions containing certain of these products.
BACKGROUND OF THE INVENTION
Amine phosphate salts have been prepared by heating an amine and the corresponding 0,0-dihydrocarbyl phosphoric acid. When trialkyl phosphates are reacted with amines, they act as alkylating agents with the product forming as illustrated below, where R and Rl are alkyl:
~RO~3PO ~ R NH2 ~~~ ~R)2Po2NRRlH2 The type of reaction is illustrated in United States Patent

2,563,506.
When R in the above reaction sequence is aromatic, no reaction bet-ween the amine and the phosphate occurs.
Nearly all phosphoramides have been synthesized from phosphoryl chloride and amines. This reaction is adequate for academic research, but it is impractical for commercial production of oil-soluble products, because the water-washing step required for removal of chlorides causes severe emulsi-fication problems.
SUMMARY OF THE INVENTION
It has now been found that certain boron-containing catalysts can be used to prepare amine phosphate salts or mixtures of amine phosphate salts and phosphoramides from triaryl phosphates and aliphatic amines.
The reaction between a triaryl phosphate and a primary or secondary aliphatic amine is catalyzcd by boric acîd to yield rapid, selective formation of the amine phosphate salt.
The reaction between a triaryl phosphate and a primary or secondary ~1 166~7 aliphatic amine is catalyzed by trialkyl borate to yield a mixture of amine phosphate salts and phosphoramides.
Phosphoramides can he prepared by methods that require no chloride removal, when a triaryl phosphate and a primary or secondary aliphatic amine are reacted in the presence of boron trifluoride to yield predominantly a phosphoramide or bisphosphoramide along with a minor amount of the amine phos-phate salt.
Thus this invention provides a process comprising heating a triaryl phosphate and a primary or secondary aliphatic amine in the molar ratio of 1:1-20 respectivelyJ at a temperature of 100-200C for 0.5 to 30 hours in the presence of a catalytic amount of a boron-containing compound selected from boric acid, trialkyl borate wherein the alkyl portion contains from 2 to 6 carbon atoms, and boron trifluoride, to yield a phosphate salt, a mixture comprising a minor portion of phosphoramide and a major portion of phosphate salt, or a major proportion of phosphoramide and a minor proportion of phos-phate salt, respectively.
In an alternative aspect this invention provides, as a new composi-tion of matter, the product of the process of this invention.
Certain of the products prepared by the process of this invention are particularly useful as anti-oxidants, anti~wear agents and friction-modifying additives for lubricating oils.
DETAILED DESCRIPTION OF ~THE INVENTION
~ .
Starting Materials Preferred triaryl phosphates for use within the scope of this invention are those of the formula (Rn ~ ) 3 where R is alkyl, halo, alkoxy, nitro, trifluoromethyl, or dihydrocarbylamine 6~i27 and n is ~ero, 1 or 2.
Preferred primary or secondary aliphatic amines are those in which the aliphatic radical contains from 4 to 18 carbon atoms.
Particularly preferred starting-material phosphates and amines for preparing the lubricating oil additives are those where R is alkyl and the aliphatic amine is a primary alkyl amine containing 12-18 carbon atoms.
As used herein, the following terms have the meaning set forth below.
"Aryl" means a compound containing at least one aromatic, 6-carbon-membered ring. It may contain other cycloaliphatic rings and/or any substi-tuent groups that do not adversely affect the desired reaction path.
"Primary amine" means an amine having two hydrogen substituents and one non~hydrogen substituent that is bonded by a carbon bond to a nitrogen atom, "Secondary amine" means an amine having one hydrogen substituent and two non~hydrogen substituents that are bonded by a carbon bond to a nitrogen atom.
"Aliphatic" means a non-aromatic, carbon~containing radical which is either saturated or unsaturated, that is contains one or more olefinic or acetylenic sites of unsaturation. The aliphatic radical may not contain any substituents that would adversely affect the reaction of this invention.
Preferably the aliphatic group contains only carbon and hydrogen and consists of 3 to 30 carbon atoms.
"Alkyl" means a saturated aliphatic carbon chain of 1 to 30 carbon atoms which contains only carbon and hydrogen atoms.
"Halo" means fluoro, chloro, bromo or iodo.
"Alkoxy" means the radical alkyl-O- where alkyl is as defined above.
"Hydrocarbyl" means a Cl~C30 aliphatic or C6-C30 aromatic hydrocarbon radical containing only carbon and hydrogen atoms.

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11~l6627 Reaction Conditions The reaction is preferably carried out by combining in the reaction mixture from 1 to 20 mols of amine per mol triaryl phosphate. Generally the reaction proceeds most efficiently when the molar ratio of reactants is 2-3 mols of amine per mol of triaryl phosphate, The reaction usually proceeds to completion in from 0.5 to 30 hours when a reaction temperature of 100-200C is employed.
Excess amine, aromatic by-products and catalyst can be removed, if desired, from the reaction product by vacuum distillation at 100-1000 Pa ~0.75-7.5 mm Hg) and a pot temperature of about 100-170C.
A catalytic amount of the boron-containing catalyst must be present in the reaction mixture. Preferably, 1-5 weight percent based on the total weight of amine and phosphate, and most preferably 3-5 weight percent, of the boron-containing compound is used as catalyst. The boron compounds for use as catalysts within the scope of this invention are boric acid, boron trifluo-ride, and trialkyl borate of the formula ~R30)3B, wherein R3 is alkyl of 2 to 6 carbon atoms Preferably the alkyl group is ethyl, propyl, amyl, butyl, or hexyl. Most preferably, the alkyl group is butyl.
If desired, the reaction may be carried out in the presence of a hydrocarbon diluent; however, the reaction usually proceeds satisfactorily in the absence of any solvent or diluent.
Uses The amine phosphate salts and mixtures thereof with phosphoramides prepared by the process of this invention have a variety of uses, such as lubricating oil additives, thickening agents, and biocides.
Lubricating Oil Com~ositions The preferred starting materials for preparing compositions of this invention for use in lubricating oil compositions are described above. These

- 4 -.,~

~.166;27 compositions are particularly useful as anti-oxidant, anti-wear and friction-modifying additives for lubricating oils. Their use in oils reduces the power lost between sliding parts and can increase the number of miles per gallon of fuel that an engine can produce.
The lubricating oil compositions of this invention can be prepared by mixing an oil of lubricating viscosity with from 0.01 to 10% by weight of the desired phosphorus compound as additive. The amount of additive w}lich may be present in the lubricating oil in order to impart the desired properties varies with the type of additive, the type of lubricating oil, and the pre-sence of other additives. This type of variation is well known in the art.In general, the preferred additive concentration is 0.05 to 2~ by weight based on the weight of the final lubricating oil composition.
The lubricating oil which may be employed in the practice of this invention includes a wide variety of hydrocarbon oils. Other oils include lubricating oils derived from coal products and synthetic oils, e.g., alkylene polymers ~such as polypropylene, polybutylene, etc,, and mixtures thereof), alkylene oxide-type polymers (e.g., alkylene oxide polymers prepared by poly~
merizing alkylene oxides such as propylene oxide, etc., in the presence of water or alcohol, e.g., ethyl alcohol~, carboxylic acid esters ~e.g,, those which were prepared by esterifying carboxylic acids such as adipic acid, azelaic acid, suberic acid, sebacic acid, alkenylsuccinic acid, fumaric acid, maleic acid, etc., with the alcohol such as butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, pentaerythritol, etc., liquid esters of phosphorus, such as trialkyl phosphate ~tributyl phosphate), dialkylaryl phosphate, triaryl phosphate ~tricresyl phosphate), etc., alkylbenzenes, polyphenols ~e.g., bisphenols and terphenols), alkylbiphenylethers, esters and polymers of silicon, e.g., tetraethyl silicate, tetraisopropyl silicate, hexyl-~4-methyl-2-pentoxy) disilicate, poly~methyl)siloxane and poly~methylphenyl)siloxane, etc. The

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~166;~7 lubricating oils may be used individually or in combinations whenever miscible or whenever made so by use o mutual solvents. The lubricating oils generally have a viscosity which ranges from 50 to 5000 SUS ~Saybolt Universal Seconds) and usually from 100 to 1500 S~S at 100F (38C).
In addition to the compositions of this invention, other additivec may be successfully employed within the lubricating compositions of this inven-tion without affecting their high stability and performance over a wide tem-perature scale. One type of additive is an anti-oxidant or oxidation inhibitor.
This type of additive is employed to prevent varnish and sludge formation on metal parts and to inhibit corrosion of alloyed bearings. Typical anti-oxidants are organic compounds containing sulfur, phosphorus or nitrogen, such as organic amines, sulfides, hydroxysulfides, methanols, etc., alone or in combi-nation with metals such as zinc, tin or barium. Particularly useful anti-oxidants include phenyl-alpha-naphthyl-amine, bis(alkylphenyl)amine, N,N'-diphenyl-p-phenylenediamine, 2,2,4-trimethyldihydroquinoline oligomer, bis(4-isopropylaminophenyl) ether, N-acylaminophenol, N-acylphenothizaines, N hydro-carbylamides of ethylenediamine tetraacetic acid, alkylphenol-formaldehyde-amine polycondensates, etc.
Another additive which may be employed is a rust inhibitor. The rust inhibitor is employed in all types of lubricants to suppress the formation of rust on the surface of metallic parts. Exemplary rust inhibitors include sodium nitrite, alkenylsuccinic acids and derivatives thereof, alkylthioacetic acid and derivatives thereof, substituted imidazoles, amine phosphates, etc.
Another additive which may be incorporated into the lubricant composition of this invention is an anti-corrodant. The anti-corrodant is employed to inhibit oxidation so that the formation of acidic bodies is suppressed and to form films over the metal surfaces which decrease the effect of corrosive materials on exposed metallic parts. Typical anti-corrodants are organic compounds .
": . ' ~ ', ' : '" '' .

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-' ~ ' :1~1.16~Z~7 containing active sulfur, phosphorus or nitrogen, such as organic sulfides, phosphides, metal salts of thiophosphoric acid, cyclic and acyclic epoxides and sulfurized waxes, barium phenates and sulfonates, etc. A particularly effective corrosion inhibitor is a~lonium dinonylnaphthYlene sulfonate.
Other types of lubricating oil additives which may be employed in the practice of this invention include anti-foam agents (e.g., silicones, organic copolymers), stabilizers, anti--stain agents, tackiness agents, anti-chatter agents, dropping point improvers, anti-squawk agents, lubricating color correctors, extreme-pressure agents, odor control agents, dispersants, detergents, etc., as well as other anti-wear agents such as tricresyl phosphate and zinc dithiophosphate esters.
In many instancG:s, it may be advantageous to form concentrates of the reaction product of this invention within a carrier liquid. The employ-ment of concentrates provides a convenient method of handling and transporting the reaction products for their subsequent dilution and use. The concentration of the reaction product within the concentrates may vary from 10 to 90 weight percent, although it is preferred to maintain the concentration between about 20 and 80 weight percent.
ILLUS~RATIVE E~.~MPLE
To a l-liter flask was added 109 g (1/3 mol) triphenyl phosphate and 215 g ~1 mol) cocoamine (96% n-dodecylamine). Thc reaction mixture was heated with stirring at 150C under nitrogen for 4 hours. Analysis by in~rared at the end of 4 hours indicated that little to no reaction had taken place.

To a reaction vessel was added 326.3 g (1 mol) triphenyl phosphate in 215 g (1 mol) n-dodecylamine (98% pure) and 27 g (5% by weight) of boron trifluoride in phenol. The reaction mixture was stirred at 150C for 4 hours.

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~lfi6~'7 The prcduct contained 7.0% P and 3.1% N and had an aci-' number of 39 mg KOH/g and alkalinity value of 1 mg KOH/g.
EX~MPLE 2 To a 2-liter reaction flack wns acded ~3C g (2 mols) cocoanine (96n n-dodecylamine), 326.3 g (1 mol) triphenyl phosphate, and 37.8 g (5% by weight) of boror trifluoride ethe:cte. The reaction mixture was heated to 150C for 4 hours and then stripped to 150C at 4 mm Hg, to yield 768.9 g of product.
Analysis: 5,9% P, 3.4% N, acid number 34 mg KO~I/g, alkalinity value 15 mg KOH/g.

To a 3-liter flask was added 575 g cocoamine (96% n-dodecylamine) and 715 g n-dodecylamine ~98% pure) (6 mols total), 652.8 g (2 mols) triphenyl phosphate and 38.4 g (2% by weight) boric acid. The reaction mixture WâS
stirred at 200C for 8 hours. Analysis by infrared indicated the reaction is complete. The reaction mixture was then stripped at 200 C and 3 mm Hg to yield 1177 g of overhead distillate. The residue was then filtered hot through â thin pad of diatomaceous earth to yield 734 g of product. The product con-tained 3.48% nitrogen, 7,55% phosphorus, and had an alkalinity value of 67.2 mg KOH/g.
EXAMPL~ 4 To a 500-~,1 flask was added 163.2 g (0.5 mol) triphenyl phosphate and 107.5 g (0,5 mol) cocoamine (96% n-dodecylamine) and 10.8 g (4 weight percent) boric acid. The reaction mixture was stirred at 130C for 10 hours.
The reaction mixture was then stripped at 165C and 3 mm Hg to yield 197.9 g of product.
E`^~?PLE 5 To a 2-liter flask was added 326.3 g (1 mo?) triphenyl phosphate, 645 g (3 mols) cocoamine (S61 n-dodecylar;ire, ?lld ~ g (4 weight percent) ....

.

i627 boric aci~i. The reac~io~ ture was stirred ~t 120C for 10 hours under a nitrogen atmosphere. The mixture was then stripped to 165C at 4 ~1 Hg, yie]d-ing 571.8 ~ cf product.

To a l-liter flash was added 108.8 g ~1/3 mol) trip~leriyl phosphate, 215 g ~1 mol) cocoamine ~96% n-dodecy'~ine) and 16 g ~5 weight percent) boric acid. The reaction n~ixture wzs stirred under nitrogen at 150C for 4 hours.
Analysis by infrared indicated that the reaction was essentially conm~lete after 5G minutes. The re~ction mixture was stripped to 150C at ~ mm Hg.
-~XI~'.PLE~7 To a l-liter flask was added 326.3 g ~1 mol) triphenyl phosphate, 430 g ~2 mols) cocoamine ~96 n-dodecylzmine) and 38 g ~5% by weight) tri-n-butyl borate. The reaction mixture was stirred at 120C for lO hours and at 130C for 5 hours.
~E~A~PLE 8 To a 2-liter flask was added 645 g ~3 mols) cocoan~ine (96% n-dodecylamine), 326 g (1 mcl) triphenyl phosphate and 49 g ~5% by weight) tri-n-butyl borate. The reaction mixture was stirred at 120 C for 10 hours and then stripped to 150C at 2-3 mm Hg. Product analysis: 5.3O P, 2,9% N, acid nu~ber 86 mg KCH/g, alkalinity value 103 mg KOH/g.
EX/U?~LE a To a 3-liter flask were added 967.5 g ~4,5 mols) cocoamine ~96% n-dodecylamine), 489 g ~1.5 mols) triphenyl phosphate and 73.5 g (5% by weight) tri-n-hutyl borate. The reaction mixture was stirred under nitrogen at 120C
for 10 hours and then stripped to 150C at about 2 mm Hg. Product analysis:
5.4% P, 2.3% N, acid number 79 mg KOH/g, alkalinity value 96 mg KOH/g.
Thc analysis of the products of Examples 1-9 is presented in Table I, which shows the percent distribution of the various amine-phosphorus C _ 9 -6Z~

compounds in the final procluct. The structure of the compounds was determined by phosphorus nucleas magnetic resonance.

Molar percentage distribution in final product prepared in Fxample:
Product 1 2 3 4 5 6 7 8 9 ~o-P-~NHR)2 3 12 4 0 0 0 5 2 3 o (~0)2P-NHR 73 76 5 2 315 2 3 2 o ~032P-02NH3R (salt) 5 5 3871 9274 62 8174 ~033P O starting material11 1 1 27 5 0 3114 21 r~O)2PI-NR O 0 5 0 0 0 0 0 0 L ~2 Other Product 8 6 47 0 011 0 0 0 The coefficient of friction of a lubricating oil containing the additives prepared by the process of Examples 2, 5 and 8 were tested in the Kinetic Oiliness Testing Machine ~KOTM) manufactured by G.L. Neeley of Berkeley, California. The procedure used in this test is described by G.L.
Neeley, Proceedings of Mid-Year Meeting, American Petroleum Institute, 1932, 10pp. 60-74. Friction was measured in this test under boundary conditions with a load of 100 pounds ~12 MPa), speed of 0.1 rpm ~0.5 mm/sec). The oil being tested is an SAE lOW40 oil containing 8.4% of a polyacrylate viscosity index improver and also containing a conventional polybutene succinimide dispersant, zinc dialkyl dithiophosphate and overbased magnesium sulfonate. The results in Table II below show good reduction in the coefficient of friction on both metal combinations tested and at all temperatures tested.

" ,, ,,~,~ - 1 0 ., .~, i6Z7 TABLE II
Effect of Product on Coefficient of Friction Product of Coefficient of Friction at Metal SurfaccsEx. No. Wt. % 50C 100C 150C 200C
Chromium sliders on) 2 0 0.13 0.13 0.13 0.14 Cast Iron Track ) 1 0.13 0.12 0.12 0.12 52100 Steel Sliders) 2 0 0.14 0.13 0.13 0.15 on Cast Iron Track ) 1 0.12 z 0.11 0.11 0.12 Chromium sliders on) 5 1 0.11 0.10 0.11 0.12 Cast Iron Track 52100 Steel Sliders) 5 1 a.10 0.080 0.082 0.099 on Cast Iron Track 52100 Steel Sliders on) 8 0 0.13 0.14 0.15 0.16 52100 Steel Track ) 1 0.055 0.038 0.038 0.071 This reduction in coefficient of friction noted for the product of Example 8 results i.n a fuel savings in a V-8 engine of the following percents at the speeds noted:
Speed, mph Savings~ %
Q (idle~ 1.2

6.5 2.1 , .. .

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process comprising heating a triaryl phosphate and a primary or secondary aliphatic amine in the molar ratic of 1:1-20 respectively, at a temperature of 100-200°C for 0.5 to 30 hours in the presence of a catalytic amount of a boron-containing compound selected from boric acid, trialkyl borate wherein the alkyl portion contains from 2 to 6 carbon atoms, and boron trifluo-ride, to yield a phosphate salt, a mixture comprising a minor portion of phosphoramide and a major portion of phosphate salt, or a major proportion of phosphoramide and a minor proportion of phosphate salt, respectively.

2. The process of Claim 1 wherein the triaryl phosphate has the formula where R is alkyl, halo, alkoxy, nitro, trifluoromethyl, or dihydrocarbyl amino, n is zero, 1 or 2, and the aliphatic amine has the formula where R1 is an aliphatic radical containing 4-18 carbon atoms and R2 is hydro-gen or an aliphatic radical containing 4-18 carbon atoms, and 1-5 weight per-cent of the boron-containing compound is employed.

3. The process of Claim 2 wherein 3-5% boron-containing compound is employed, the trialkyl borate is triethyl borate, tripropyl borate, tributyl borate, triamyl borate or trihexyl borate, and the molar ratio of phosphate to amine is about 1:2-3.

4. The process of Claim 3 wherein R is alkyl, R1 is alkyl of 12-18 carbon atoms, and R2 is hydrogen.

5. The product prepared by the process of Claim 1.

6. The product prepared by the process of Claim 2.

7. A lubricating oil composition comprising an oil of lubricating viscosity and from 0.01 to 10% by weight of the product of Claim 5 or 6.

8. A lubricating oil concentrate comprising from 10-90%
by weight of an oil of lubricating viscosity and from 90-10% by weight of the product of Claim 5.

9. A lubricating oil concentrate comprising from 10-90%
by weight of an oil of lubricating viscosity and from 90-10% by weight of the product of Claim 6.

10. A method for reducing the friction between relatively moving parts comprising lubricating said parts with the lubri-cating oil composition of Claim 8 or 9.