US2406575A - Preparation of an improved lubricant - Google Patents

Description

cosity index which have erties; and relates particularly to lubricants con- 'to, thicken thelubricant and also "polyisobutylene .well under conditions where lubrication of sur- I sulfur and chlorine ,as 2-methyl pentadiene temperatures by the mide or'stannic T perature with element selected from the sulfur group. -,;ji erred P386, P480 or P2865 1 treatment very efiective Patented Aug..27, 1946 I PREPARATION ormmraovnn I LUBRICANT I David W. Young, Roselle, N. 1., Hlneline, Mount Vernon, N.

and Harris D. Y., assignors to- Standard Oil Development Companyga cor poration of Delaware I No sawing, v

Appllcation luly s, 1944,

Serial No. 544,148 11 Claims. (crass-46.6)

1 This invention relates to thickened having an improved viscosity index;

pcially relates esextremepressure proptaining phosphorous pentasulfide treated, cyclicized polymer such as polymethyl pentadiene.

' A number of oil soluble substances have been fomid, which serve when dissolved in lubricants to improve its viscosity index; that is, to reduce the rate of I change of viscosity with change in temperature of the lubricant; among the best of which has been polyisobutylene. Polylsobutylene, however, lacks extreme pressure lubricating properties, and while the viscosit indexis excellent, it does not stand up faces under extremely heavy pressure is required. On the other hand, various substances have been offered which contain such inorganic radicals as which improve the extreme pressure properties of the'lubricant, but do not culty is encountered in adding both agents and obtaining satisfactory results.

The present invention provides a single soluble addition agent which, tains both V. I. improving elementsand E. P. im-

proving elements and is found to yield an excellent viscosity index, and, simultaneously, excellent extreme pressure properties. v

For this purpose a polymerizable polyoleiin such 1,3- is polymerized at low application of a Friedel Crafts catalyst dissolved in a low freezing, noncomplex formin lar weight polymer: which the application of an appropriate cyclicizing agent such'as p-toluene sulionic acid or aluminum brochloride or The presubstance is phosphorous pentasulflde or P236 or P488 01' F286;. This mer) a considerable quantity of combined phosphorous; which, together yield the high molecular weight or the cyclicized polylubricants to thickened lubricants of improved vis.

of a lubricating 011 containing improve the viscosity index; and difiithe polyolefins having in a single substance, con per molecule,

, the like. The cyclic-. ized polymer is then treated at an elevated tem-' a compound of phosphorous and an adds-into the cyclicized polymer (or into the oil blend containing the cyclic'lzed polyof combined sulfur (or selenium or tellurium) and a smaller quantity extreme pressure properties whilepolymer which is preferred raw material is polymethyl p ntadiene;

that is the polymer of 2, methyl 'pentadiene-1,3 v quite r'eadmer yields the desired thickening and-the desired.

improvement in viscosity index. I

Thus the present invention provides a, new composition of matter comprising a hydrocarbon solu-- tion of a cyclicized polymer such aspolymethyl pentadiene containing combined sulfur, and smaller or negligible quantities of combined phos phorous, dissolved in a hydrocarbon lubricant to yield a solution which remains liquid at low temperatures, and retains its body at relatively high temperatures. Other objects and details of the invention will be apparent from the following dev scription.

The raw material for the present invention is a relatively high molecular weight polyoleilnic capable of. cyclicization. The

which polymerizes at low temperature ily into high molecular weight polymers, and when so polymerized cyclicizes quite readily. After nativel almost any of the other high molecular weight polyolefinic polymersare useful. Thus,

such polyolefins as 2,5-methyl pentadiene-1,3

or 2-methyl-5.-ethyl pentadiene-1,3 or the like are similarly useful. That is, substantially any of more than 5 carbon atoms in which there is an aliphatic sub- I stituent on the second carbon atom with a double solvent; to yield a high'molecuis, the cyclic-ized by I I Alternatively, other analogous compounds may be used,such for example as P453,

linkage between the first and second carbon atom, v

is useful. Those compounds which are c'onju gated, that is, contain two double linkages separated by a single linkage, are preferred, but the condition of conjugation is not necessary.. The limiting molecular carbon atoms per molecule polymerized and cyclicized, and are reactive with phosphorous pentasulfide; fins including such ing the formula A I cmnmcncmcme-cmo'm are very desirable raw materials, since they poly- I -merize readily, cyclicize readily, are oil-soluble Y when polymerized readily with phosphorous pentasulflde after cy and cyclicized, and combine cyclicization. Similarly, the triolefln known as alloocymene,having the formula I is qually advantageously useful. These subsize of the compounds isstill unknown, but compounds as high as 12 or 14 are useful. All of these dioleflns polymerize reasonably readily, 1 -cyc'licize readily, are soluble in hydrocarbons when Similarly, the triole substances as myrcene, havof good purity is used. In

noncomplex forming solvent.

Crafts halides, especially aluminum stances are representative of polyoleflns which polymerize at temperatures below C. into oil soluble polymers having molecular weightsabove 3000, 4000 or 5000, up to several hundred thousand, with iodine numbers ranging from about 100 to 330 or above, which are readily cyclicized to reduce the overall unsaturation, yet retain, in the cyclicized condition, sufiicient unsaturation to he reactive with phosphorous pentasulfide; and when so reacted, combine with the phosphorous and sulfur in such a way that the solubility in hydrocarbons remains good, the inorganic atoms are solidly held so that the compound is stable, yet the inorganic molecules are so placed as to result in an effective extreme pressure improvement.

Of these compounds, the polymer of methyl pentadiene is preferred.

In preparing this polymer, methyl pentadiene' after given, a methyl pentadiene having a boiling point of 75 C. to 77 C. (at 760 mm. of Hg), 9. density of 0.7113 and 1.4472 was used. This material has a purity better than 95 and further determinations indicate that its purity is in fact approximately 98%. The methyl pentadiene is cooled to a temperature about between 0 C. and -l64= a temperature between -40 propane, and '103 C.) as set by liquid C. as set by liquid ethylene.

The methyl pentadiene by itself may be, cooled, by the application of a refrigerating Jacket to the polymerization reactor. Alternatively the methylv diluted with such substances pentadiene may be as the lighter hydrocarbons or the alkyl, mono, or poiyhalides or carbon disulfide or the like. Alternatively the methyl pentadienemay be cooled by an internal reirigerant-diluent. For this purpose such substances as liquid propane or liquid'ethane or The cold methylpentadiene is then polymerized by the application of a Friedel-0rafts catalyst which preferably is in solution in a low freezing The Friedel-Crafts catalyst may be substantially any of the substances disclosed on The Friedel-Crafts Synthesis Journal of American Chemical $ociety at Baltimore in 1935 in volume XVII, No. 3, the article beginning on page 327, the list being particularly well shown on page 375. These Friedel-Crafts active metal halides may be used as such in single salts, or

printed in the oral metals or several halides or even with alkoxy substituents. These catalysts may be solid, liquid or gaseous (boron trifiuoride being gaseous; titanium tetrachloride being liquid; most of the remainder being solids). mouohalides are preferred such as methyl or ethyl chloride. Other alkyl mono or peiyhalides having melting points below 0 C. are also useful; as is carbon disulfide. All of these substances show an adequate solvent capacity for the Friedelchloride which is the preferred catalyst. Alternatively, and especially where catalyst complexes containing several halides, are used, the lighter hydrocarbons such as propane, butane, pentane, hexane, and the like may be used; the principal requirements being a solubility of at least 0.5% for the examples hereinan index of refraction N C. (preferably to liquid ethylene or even liquid methane may be used; or the material may bisby N. 0. Galloway in his article Chemical Reviews, published for the For solvent, the alkyl the active methyl halides and a freezing point below 0 C. (thereby being low freezing). The catalyst solution may be added to the cold olefinic material in anyconvenient manner which 5 will bring the catalyst solution quickly into intimate dispersion in the cold olefin. A convenient siredpolymer, and the conversion may be carried to a yield of from 40-50% of the amount of methylpentadiene present, to a yield as high as 90-95%. Such high yields are, however, less desirable since the range of molecular weight is greater. When the reaction has reached the desired stage, the catalyst supply is interrupted. The solid polymer may be recovered in any desired manner; merely by boiling off residual unpolymerized methylpentadiene; and refrigerate if present, or the reaction mixture may be treated with warm water or warm alcohol or warm naphtha, with or without small quantities of alcohol 'or the like. I v

The resulting polymer may have a molecular weight almost anywhere between 2000, 3000 or -12,000 and 30,000-100,000, depending upon the lowness of the polymerization temperature, the

purity oi the methylpentadiene, the presence and purity of diluent-refrigerant, and the character of catalyst chosen. The preferred molecular weight is within the and 35,000 to 45,000 since higher molecular somewhat more easily in service and lower molecular weights require an rgim temperature and is ready for the dissolving S D.

Alternatively; the polymer may be dissolved in light naphtha and treated with stannic chloride at temperatures ranging from 20 C. to 00 C. for time intervals ranging from 15 minutes to 80 hours. This treatment also is effective for cyclicization, and likewise reduces the iodine number to approximately 15 to 50.

Other methods which will be obvious to those skilled in the art may likewise be used for this cyclicizs-tion step.

the phosphorous pentasulfide treatment.

The polymer is then dissolved in from 0.5% to 10% or 15% in the desired hydrocarbon lubricant. For the production of a fluid lubricant, a high grade, well refined oil having a viscosity at The reaction proceeds rapidly to yield the de- I range between about 5000 The polymer is then ready for desired values. is to be made,

150". C; to 225 C. for

' polymer be oil-soluble.

linkages, which I butylene, down to 0.-

210 F. of from 30 S. S. U. to '70 S. S. U. may be used, sufficient polymer being dissolved in the oil to bring the viscosity and viscosity index to the Alternatively, if a heavy grease a much heavier lubricant stock addition agents be incorporated; ofthe may be utilized and the various used to make heavy greases may together with from 1% to 15% or 20% polymer.

To this solution there is then added a substantial quantity of phosphorous pentasulfide, the

amount ranging from 1% to or of the amount of cyclicized polymer. The oil solution is then heated to temperatures ranging from from 15 minutes to 150 minutes. The solution is then filtered to remove any uncombined phosphorous pentasulflde, and

products, the material -being preferably filtered while hot because of the more rapid filtering rate. In the preparation. of greases it is, of course, desirable that the auxiliary components be added after the filtration step.

Th above outlined procedure applies particularly to methylpentadiene, and to its polymers,

any insoluble reaction but substantially the same procedure may be applied to a wide range of polymerizable substances, polymers, and high molecular weight substances in general, it being merely necessary that they be capable of cyclicizatlon; when cyclicized be soluble in hydrocarbons, and when cyclicized retain a suificiently high iodine numher, and a sufficient amount of unsaturation to combine with the phosphorous pentasulfide.

Thus, for instance, an interpolymer of isobutylene with a polyolefin having more than 5 carbon atom in which a substantial quantity of the polyolefin is interpolymerized, is similarly useful, especially with polyolefins up to 12 or 14 carbon atoms per molecule and especially when the quantity of polyoleiin interpolymerized is subtion of sulfur without cross linkages retains the oil-solubility and it is of the essence of the present invention that, broadly, the polymer is cyclicized and 'sulfurized without the introduction of cross linkage, in order to obtain a compound of high molecular weight which contains substantial quantities of combined sulfur (the effect of which is aided by the presence of smaller quantities of phosphorous) and accordingly, the invention is applicable to any polymer which can be 'cycliclzed and combined with phosphorous pen-tasulfide without the formation of sufiicient cross linkages to destroy the solubility in hydro- Example 1 Approximately 100 parts of methyl pentadiene having a purity of approximately 95% were cooled to a temperature or approximately 88 C. by the addition thereto of approximately 300 parts of liquid ethane. The mixture was then polymerized by the addition of approximately 50 parts of a solution of aluminum chloride in ethyl chloride having a concentration of approximately 2%, the catalyst solution being sprayed on to the surface of the rapidly stirred oleflnic mixture. The polymerization proceeded quickly to yield a solid polymer having a molecular weight of approximately 40,000. The polymerization mixture was thrown into hot water stantial in amount. That is, it is desirable that the polyoleiins having more than 5 carbon atoms, but not a characteristic of butadiene, and the presence of butadiene per se to the extent of more than about 20% introduces so much cross linkage upon cyclicization as to render the cyclicized polymer useless. Thus, copolymers of isobutylene with butadiene or isc-prcne or piperylene, containing from 2% to 15% or 20% of butadiene are usable. Copolymers of isobutylene with dimethyl butadiene, myrcene, dimethallyl and the like, up to 12 or 14 carbon atoms, are usable, especially when the proportion of interpolymerized diolefins exceeds 5% or 10%. Likewise, as will be evident from the above description, these polyolefins may be used with any proportion of isothe phosphorous pentato volatilize residual refrigerant and to separate. unpolymerized methyl pentadiene. The yield was approximately 80%. lhe polymer was then placed on the double roll mill, washed with water until most of the residual traces of catalyst were removed. and then approximately 3 parts by weight (per hundred of polymer) of p-toluene. sulfonic acid were added and thoroughly milled into the solid polymer. The milling was continued until a thoroughly homogeneous mixture was obtained. The solid mixture was then placed in a hot air ovenat 100 C. for 30 minutes.

The mixture was then cooled and approximately 50 parts by weight of the polymer were dissolved in 1000 parts by weight of a high grade parafilnic mineral lubricating oil which had a visis found to be a characteristic of cosity at 210 1". of 52 S. S. U. and a V. I. of 98. .When the solution was complete, yielding a clear fluid solution, approximately 50 parts by weight of powdered yellow phosphoric pentasulflde P285 was added, well stirred in and the mixture heated to a temperature of 180 C. for 30 minutes, the mixture being well stirred during the heating step. At the end of the 30 minutes, the mixture was cooled to approximately 25 C. and filtered 55 through a paper filter to yield a clear filtrate.

Chemical analysis of the clear filtrate showed that it contained 0.58% of phosphorous and 2.03% of sulfur. v

Viscosity determinations and viscosity index determinations showed the following inspection results:

, S.B.U.vis S.S.U.vls-

coslty at cosity at 210 V. I.

F. F. 488 74 l 131 These results show that the resulting oil has an excellent viscosity and an excellent viscosity index.

Other portions of this oil product were then charged into the Almen machine for the usual 30 second run. At the end of the 30 seconds, the successive 2 lb. weights were added at 10 second interaeoaert vals until the full number or 15 weights had been added. The oil carried all 15 weights. The pin an bushing were made of steel-and at the end of the test the pin and bushing werein good condition.

Example 2 was then polymerized by the addition of approximately '75 parts by volume of a solution or aluminum chloride in methyl chloride in a concentration or approximately 0.8%. The polymerization was conducted by spraying the catalyst solution onto the surface oil the rapidly stirred oleilnic material. The polymerization proceeded rapidly to yield a solid polymer having a molecular weight (by the Staudinger method) of approximately rescue. The polymerization mixture was then then thrown intowarm Water to volatilize residual traces of refrigerant and to separate out any unpolymerized methyl pentadiene. The yield of polymer was approximately 69%. The solid polymer was then placed on a double roll mill and washed with water until most of the residual traces of catalyst and monomer were removed.

When this stage was reached, approximately 10 parts by weight (per 100 of polymer) of p-toluene sulfonic acid were added and thoroughly milled into the solid polymer. The milling was continued until a thoroughly homogeneous mixture was obtained. The mixture was then-placed in a hot air oven at 100 C. minutes. lhe brown polymer mixture was then cooled and approximately 50 parts by weight of the polymer were dissolved in 1000 parts by weight of a good lubricating oil which had a. viscosity at 100 F. of 128 S. S. U., a viscosity at 210 F. of 42 S. S. U. and

v. I. of 109. When the solution was about complate, approximately 50 parts by weight of powdered yellow phosphorous pentasulfide (Pass) was added and well stirred in. The mixture was then heated to a temperature of 180 C. for 60 minutes, the mixture being well stirred during the heating period. At the end of the 60 minutes the mixture was cooled to approximately 35 C. and filtered through a paper filter to remove residual traces of, uncombined phosphorous pentasulilde'and to yield a clear filtrate. The filtrate was then blown with air, using about 5 cubic feet per hour per kilo of solution for a period of 2 hours to remove traces of hydrogen sulfide and to deodorize the oil.

Chemical anaylsis or the clear, odorless filtrate showed that it contained 0.8% of combined phosphorousand 2.88% of combined sulfur. Viscosity determinations and viscosity index determine:

tions showed the 'followinginspection results;

s. s. U. at s. s. U. at v.1.

d ried all 15 weights under this shock loading and after the test the pin and bushing. which were made of steel, were in good condition.

The oil was then tested under gradual loading conditions in the 'Almen machine as outlined in Example 1. The cyclicized P255 treated polymer in solution in the oil carried all weights.

1 These results indicate that the oil prepared as a above described is a high grade lubricant having a very advantageous viscosity index and a very val.- uable extreme pressure property.

While there are above disclosed but a limited number of embodiments of the invention, it is out departing from the inventive concept herein disclosed and it is, therefore, desired that only such limitations be imposed upon the appended claims as are stated therein or required by the higher art. The invention claimed is:

1. An improved lubricant comprising a hydrocarbon lubricating agent having dissolved therein .5 to 20% of polymer of a polyolefin having more than 5 carbon atoms per molecule which is char-- acterized by cyclicization and the presence or phosphorous sulfide.

' 2. An improved lubricant comprising in combination a hyrh'ocarbon material and a solute therein comprising .5% to 20% of a cyclicized.

comprising .5 to 20% of a cyclicized, phosphorous pentasulfide treated. polymer of myrcene. v

6. An improved lubricant comprising in com-- bination a hydrocarbon oil and a solute therein comprising .5 to 20% of a cyclicized, phosphorous pentachloride treated, polymer of allo-ocymene.

7. The method of preparing a lubricant comprising the steps in combination of polymerizing a polyolefin having from 6 to l'carbon atoms per moleculecyclicizing the polymer, treating the cyclicized polymer with a compound of pliesphorous and an element from the sulfur group and dissolving .5 to 20% of the cyclicized phosphorous compound treated polymer in a lubricating material. I

-8. The method of preparing a lubricant com prising the steps in combination of polymerizing a. polyolefin having from 6 to 14 carbon atoms per molecule, cyclicizing the polymer, dissolving the cyclicized polymer in a hydrocarbon liquid, treating the cyclicizec polymer with a compound or phosphorous and an element from the sulfur group and dissolving .5 to 20% of the cyclicized phosphorous compound treated polymer in a. lu-

bricating material.

9. The process of preparing a lubricant come prising the steps in combination of polymerizing a methyl pentadiene, cyclicizing the methyl pentadiene, dissolving .5 to 20% of the cycliclzeo possible to provide still-other embodiments witlobination a hydrocarbon oil and solute therein I 9 v 7 methyl pentadiene in a. hydrocarbon lubricant,

and treating the dissolved polymer with phosphorous pentasulflde.

10. The process of preparing a lubricant comprising the steps in combination of polymerizing v a. methyl pentadiene, cyclicizing the methyl pentadiene by the application thereto of p-sulfonic acid, dissolving .5fto 20% of the cyclicized methyl pentadiene in a hydrocarbon lubricant, and treating the dissolved polymer with phosphorous pen- 10 V tasulflde. w