US3562161A - Polyalkylene glycol esters of ethylene-diaminetetraacetic acid as lubricant dispersants - Google Patents

Abstract

A NEW CLASS OF COMPOUNDS AND A SERIES OF NOVEL LUBRICANT COMPOSITIONS ARE DISCLOSED. POLYALKYLENE GLYCOL-ETHYL ENEDIAMINETETRAACETIC ACID ADDITION COMPOUNDS WHICH ARE USEFUL AS DISPERSANTS IN POLYALKYLENE GLYCOL LUBRICANT FLUIDS AS SLUDGE DISPERSANTS AND LUBRICANT FLUID COMPOSITIONS INCLUDING SUCH COMPOUNDS ARE DESCRIBED.

Description

United States Patent O POLYALKYLENE GLYCOL ESTERS F ETHYLENE- DIAMINETETRAACETIC ACID AS LUBRICANT DISPERSANTS Frederick F. Caserio, Jr., Laguna Beach, and Ting-I Wang,

Fullerton, Calif., assignors to Atlantic Richfield Company, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed Oct. 8, 1968, Ser. No. 775,981

Int. Cl. 'C10m 1/32 US. Cl. 252-515 4 Claims ABSTRACT OF THE DISCLOSURE A new class of compounds and a series of novel lubricant compositions are disclosed. Polyalkylene glycol-ethylenediaminetetraacetic acid addition compounds which are useful as dispersants in polyalkylene glycol lubricant fluids as sludge dispersants and lubricant fluid compositions including such compounds are described.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to chemical compositions and, more particularly to chemical compositions useful as lubricating fluid additives and to lubricating fluid compositions. Still more particularly, this invention relates to polyalkylene glycol-ethylenediaminetetraacetic acid lubricant additives and lubricant compounds.

Description of the prior art Motor fuel lubricants, such as conventional automobile motor oil or oils designed for special applications, e.g., marine, aircraft and stationary engines, conventionally include oxidation inhibitors and dispersant additives. Viscosity improvers, etc. are also conventionally added to the basic lubricant fluid to provide particular characteristics desired in the end lubricating compound.

Many hydrocarbon-based or hydrocarbon-containing additives are commercially available for use in conventional hydrocarbon lubricating fluids. It is, of course, essential that any successful additive be soluble in the lubricating fluid at all potential operating or handling conditions. Long chain aliphatic hydrocarbon substituted succinic acid-amine derivatives have been proposed as dispersant additives for hydrocarbon-based lubricant fluids, see US. Pat. No. 3,172,892, LeSuer and Norman, for example.

A new class of potentially commercially valuable lubricating fluids has been developed, however, in which most known dispersant additives are insoluble or of limited solubility. It is, accordingly, an object of this invention to provide improved dispersant additives for non-hydrocarbon lubricant fluids.

SUMMARY OF THE INVENTION A new class of synthetic crankcase oils for use in automobile engines, aircraft engines, marine engines, stationary engines and the like, are described. The basic fluid, in the preferred embodiment, is a doubly end-blocked polypropylene glycol diether polymer identified hereinafter as Ucon fluid DLB-ZOOE. It has been found that while many oxidation inhibitors useful in petroleum derived hydrocarbon lubricant fluids may be used with the synthetic crankcase oils of this invention, none of the dispersant additives previously'known are sufliciently soluble and none are otherwise successful as dispersants in the synthetic crankcase oil compositions of this invention. It is, accordingly, a principal object of this invention to provide a new and improved dispersant additive for use in propylene glycol diether polymer synthetic lubricating fluids.

3,562,161 Patented Feb. 9, 1971 Similarly, a principal object of the invention is to provide improved synthetic lubricant fluids for use as crankcase oils and as lubricants generally, which comprise polypropylene glycol diethers, as base fluids and an improved sludge dispersant additive.

A more specific object of the invention is to provide an improved dispersant additive comprising polyalkylene glycol-ethylenediaminetetraacetic acid compounds.

An additional and more specific object of the invention is to provide a lubricating composition including a polyalkylene glycol diether lubricant base fluid in combination with a sludge dispersant additive comprising polyalkylene glycol-ethylenediaminetetraacetic acid compounds.

A further and more specific object of the invention is to provide a class of polyalkylene glycol-ethylenediaminetetraacetic acids for use as lubricant additives.

A process for preparing lubricant additives and lubricant fluids constitutes an additional and still more specific object of the invention.

The provision of the specific compounds described hereinafter and the specific processes for producing these compounds and the described lubricant fluids constitutes an additional and highly specific, but non-limiting, object of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The foregoing and additional objects are accomplished in general by preparing the desired polyalkylene glycolethylenediaminetetraacetic acid (EDTA) compounds and blending the resultant product with a propylene glycol diether polymer lubricating fluid generally of the type identified as Ucon fluid DLB-200E or equivalent.

The dispersant additives of this invention are prepared,

' in general, by refluxing ethylenediaminetetraacetic acid (EDTA) with a polyalkylene glycol at a temperature sufliciently high to initiate the reaction and remove water. A solvent, such as toluene, xylene, etc., may be used during the refluxing operations, if desired.

The reaction, the formation of the polyalkylene glycol ester of EDTA is carried out under atmospheric pressure, with or without the addition of solvent, at temperature of from about C. to about 300 C., and preferably in the range of about C. to C. for from about 1 to about 500 hours, preferably from about 10 to about 200 hours.

The process is illustrated by the following specific examples showing the reaction conditions thereof.

0.1 mole of EDTA and 0.1 mole of a polypropylene glycol ether identified as Ucon fluid LB-385, produced by Union Carbide Plastics and Chemicals Department, New York, along with 100 mls. of toluene and 0.005 mole of sulfosalicyclic acid as a catalyst were introduced into a 500 ml. reaction flask. Ucon LB385 has an apparent specific gravity of 0.995 at 20 C., a viscosity index (ASTM D-567) of 144, a viscosity, Saybolt seconds, at 210 F. of 75, at 100 F. of 385, and at 0 F. of 15,000, a viscosity in centistokes at 210 F. of 14.3, at 100 F. of 83.3, and at 0 F. of 4,700, with a pour point (ASTM D-97) of 35 F. and a fire point (ASTM D-92) of 500 F. The molecular weight of the poly propylene glycol is about 12004500.

The reaction mixture was refluxed for one hour. At the end of this time there had been no color change and no H O removal. The temperature was gradually increased, with distillation of toluene, to 180 C. At this point, 1.2 ml. water and 70 ml. toluene were removed. The material was dark brown with a significant amount of coagulated solids. The solids were filtered off the solution through a fritted glass 'filter with Celite and rinsed with 50 mls. of toluene. The sample was heated to distill off the excess toluene and was then submerged in an oil no observable cloudiness or separation. An oxidation inhibitor Oronite 254 was added at a 3 percent level.

Dispersant effectiveness was tested by blending the additive to used Ucon DLB-200E obtained from engines used in dynamometer tests. The dispersant additive product of the aforementioned process was mixed with the material to be tested in a Waring Blendor for 5 minutes. The sample was observed for sludge separation, and paper chromatographic spot tests were made to determine dispersant eflectiveness. Data showing the relative eifectiveness of the composition of this invention are given in Table I along with comparative data using other known and experimental dispersant additives.

TABLE I.DISPERSANT TESTS [Waring Blendor, high speed, 5 minutes] Percent separation, hrs. settling Percent Code Number cone. Structure 24 240 Standard No. 1 100 Used Ucon from chassis dynamometer test on Chevrolet 19 72 Standard No. 2. 100 Used Ucon from chassis dynamometer test on Ford 4 58 649-29-1 Reaction product of ethylenediaminetetraaeetic acid and Ucon LB-385 polypropylene 0 5 g yeo CH CH I I RO CHzCHz OOCCH2 CH OOO-OH CH O R A n N CHzCHzN R OCH2CH2 OOCCH2 CHzCOO ?H2CH2O- R 1113) 3 )1:

649-17-1 5 (012E2 0 C O C CH2)2NCH2CH2N(CH2GO2H)2 3 28 649-7-1 2 C12H23 CHO 0 48 1 75 I N-CH2OH2CH2NHZ 01120 O 49-9-1 2 C|zHz3-CHO O C 0-0 H: 50 1 N(CH2OHzNH) CHzCHzN CH3 CO CO-CH-CmHga CnHzr-CHC 0 (EH: 649-6-1 2 N CHz-CHNH3 649-8-1 2 C zH2aCHC 0 C 0-0112 6 1 18 N(CHzCH2NH)3CH3CHzN CHBOO O0-CHC12H 649-5-1 2 C nHzg-CHC O N-CHzCHgNHCHzCHzNH1 CHsC O 5 Same as above 2 l8 5 Bls-urninopropyl piperazine 649-16-1 5 C|2H23-("HC 0\ /NCHgCHzCHgNONCHzCHzCHzNHz 1 36 CH2 0 O 649-14-1 5 C Hag-GHQ O NCH OHzNHCH CHzNHz 1 16 (31120 0 Plus C12H23-CHCO (JO-CH NCHzCH NHOHzCHzN CHzCO COOHC12 2a 64949-1 5 C1'3H23OHC O NCH2CH2NH2 3 58 5 Maleie acid plus triethylenetetramine 2 5 Ethylenediaminitetraacetic acid plus Pluronie 13-62... 5 Ethylenediaminetetraacetic aeid plus Pluronie L-101 32 5 (3H CH3 4 4s CrzHzg-CHC OzCHCHrK-O JJHCHTOR CHzCOzH TABLE I. Continued Percent separation, hrs. settling Percent Code Number cone. Structure 24 240 630-43B 2 N,N,N,N tetraethyl sebacamide 4 39 C E -CH0 0zCIICHz\O CHCHzl OR CHQG O NHCH2CII2 NH2 649-36-1 3 Reaction product of tetmpropenylsuccinic anhydride plus Ucon LB-385 3 1 19 649-35-1 5 Reaction product tetraethylenepentamine plus Ucon LB-385 2 1 4 1 Soap like deposit formed on graduate. 2 Sticky deposit formed. 3 at 72. 4 6 at 72. 5 72 at 144. 96 at 120. 7 76 at 96. E 3 at 72.

The advantages of the ester addition compounds of EDTA and polyalkylene glycol are immediately apparent from the foregoing table. The significant advantage of these compounds as dispersant additives, as compared with structurally related and similar compounds, is quite unexpected. As an examination of the table will show, it is quite impossible to predict with any degree of certainty the potential effectiveness of a compound as a dispersant additive.

While we do not wish to be bound by the following reaction mechanism, it is believed, on the basis of infrared data, molecular weight, etc., that the following equation properly describes the reaction of the inventive process. Side reactions of an undetermined nature are also believed to occur, however.

Reaction scheme wherein R and R are hydrogen or lower alkyl and n is a positive integer from 1 to 100, e.g., in the specific examples hereinbefore described.

Obviously, depending upon the reaction conditions, a mixture of mono, di, tri and tetrapolyalkylene glycol esters of ethylenediaminetetraacetic acid may be formed. The product of the aforementioned reactions comprises essentially an equilibrium mixture of these mono, di, tri and tetrapolyalkylene glycol-EDTA esters.

The lubricating compositions of this invention are preferably formed by blending the compounds heretofore described with end-blocked polyalkylene glycol ether lubricating fluids, for example, the end-blocked polypropylene glycol ether identified as Ucon fluid DLB-200E available from Union Carbide Plastics and Chemicals Department, New York. The dispersant additive concentration level 'is from 0.1 to percent generally, preferably from about 1 percent to about 25 percent, by weight. Oxidation inhibitors are also added inthe 0.1 percent to 5 percent range, preferably in the range of from 0.5 percent to 3 percent. Many conventional oxidation inhibitors were tested and found to be successful, for example, 3 percent Oronite 254 is the preferred additive but 1 percent concentration of 4,4-methylene, bis-2,6-ditertiary butyl phenol (Ethyl 702), an alkylated phenol (Lubrizol 814), phenyl alpha-naphthylamine, and

an alkylated diphenylamine (VanLube SL) were found to be successful oxidation inhibiting additives.

U-con DLB-200 fluid is amber in color, has a viscosity at 210 F. of 58.3 (SUS), at F. of 201 (SUS) and at 0 F. of 5660 (SUS). The viscosity, in centistokes, is 9.70 at 210 F., 43.2 at 100 F., 1230 at 0 F., 4140 at 20 F. and 23,800 at 40 F. The viscosity index is 161, the pour point is -50 F., the flash point is 520 F. and the fire point is 565 F. This product is described in Union Carbide Chemicals Company Advance Technical Information publication 1 -40400, June 1959. Double end-blocked lubricants of this class generally may be used in the compositions of this invention, the primary consideration being the desired viscosity and viscosity index. The manufacture and properties of these compounds is discussed by Gunderson et al., Synthetic Lubricants, Reinhold, New York, 1962, chapter 3 on Polyglycols. Reference is made to this work and the publications and patents cited therein for a complete discussion of the lubricant base stocks used in the inventive composition.

It is diflicult to overestimate the importance of providing the proper blend of lubricating fluid, dispersant additive, and oxidation inhibitor. To illustrate, using the fluids of the present invention, e.g., an end-blocked polyalkylene glycol ether lubricating base fluid, a dispersant additive of the type described, and an oxidation inhibitor, e.g., Oronite 254, there is provided a potential lifetime motor lubricant. The lubricating properties of the base fluid are not diminished under normal operating conditions; however, over long periods of time the base fluid may be oxidized to form volatile components which are discharged from the crankcase. An effective oxidation inhibitor is, therefore, necessary to prevent too rapid decomposition of the base lubricating fluid resulting in the necessity for continual addition of lubricant. Sludge is formed in every internal combustion engine from combustion products, wear products, etc. It is essential that this sludge be maintained in the lubricant and carried to an effective filter. Therefore, an effective dispersant additive is required to provide an essentially homogeneous circulating lubricant fluid in which the sludge forming materials are maintained in dispersion. As the homogeneous fluid is circulated through the oil filter, the sludge components are removed and the clean lubricating fluid is returned to the crankcase. Except for occasional addition of lubricating fluid, no additional attention need be given to a vehicles engine lubricating system. The convenience and economy of this type of fluid are immediately apparent.

The lubricating compositions of this invention, the dispersant additives, and the process for preparing these products have been set forth in rather specific terms to 7 aid those skilled in the art to understand and to practice the invention. Departures from the specific disclosure will be made by those skilled in the art based upon the principles and teachings herein and such variations may be made without departing from the spirit and scope of the invention, as defined in the following claims.

We claim:

1. A composition comprising a mixture of mono-, di-, tri-, and tetrapolyalkylene glycol esters of ethylenediaminetetraacetic acid.

2. A lubricant composition comprising a major portion of an end-blocked polypropylene glycol diether and a minor portion of polyalkylcne glycol esters of ethylenediaminetetraacetic acid.

3. A mixed ester product prepared by reacting ethylenediaminetetraacetic acid with polyalkylene glycol monoether at temperatures in the range of 75 C. to 300 C.

4. The product of the process of claim 3 wherein the 8 polyalkylene glycol monoether is polypropylene glycol monoether of the formula m ocmrhrr wherein R is lower alkyl and n is from 1 to 100.

References Cited UNITED STATES PATENTS 2/1962 Matson 252--5l.5A 2/1969 Beavers et al. 260-482P