Lubricant additive comprising mixed hydroxyester or diol/phosphorodithioate-derived borates

Disclosed herein are the reaction products of dialkyl or diaryl phosphorodithioate acids and hydrocarbyl diols, hydroxyester or related polydiols and borating agent. These reaction products are useful as additives for lubricating compositions.

NATURE OF THE INVENTION 
This invention is concenred with the borate compounds of mixed hydroxyester 
or diol/phosphorodithioates and lubricant compositions containing these 
materials. 
SUMMARY OF THE INVENTION 
In one aspect this invention comprises the reaction product resulting from 
the reaction of phosphorodithioate-drived alcohols which are co-borated 
with hydrocarbyl diols, hydroxyesters, or related polydiols. In another 
aspect this invention comprises the lubricant composition made from the 
afore described reaction product and a liquid hydrocarbon liquid. 
DESCRIPTION OF PREFERRED EMBODIMENT 
The first step in the preparation of the reaction products of this 
invention is to obtain the O,O-dialkyl or O,O-diaryl phosphorodithioic 
acid by the reacting an alcohol or hydrocarbyl phenol with phosphorus 
pentasulfide, according to the following schematic formulas: 
EQU ROH+R.sub.2 S.sub.5 .fwdarw.2(RO).sub.2 PSSH+H.sub.2 S I 
Where R is C.sub.3 to C.sub.30 hydrocarbyl or oxyhydrocarbylene radical, or 
mixtures thereof and optionally contains sulfur, oxygen, and nitrogen 
atoms. The O,O, dialkyl phosphordithioic acid and an epoxide, hydroxyester 
or diol are then reacted as follows: 
##STR1## 
where "a" ranges between 1 to 10 and where R.sup.1, R.sup.2, R.sup.3, and 
R.sup.4 are hydrogens or C.sub.1 to C.sub.30 hydrocarbyl groups, and 
optionally contain sulfur, nitrogen, oxygen, or phosphorus. Although 
ethylene oxide, butylene oxide, and cyclohexene oxide in particular can be 
used, preferred are propylene oxide and butylene oxide. 
The resulting product is then reacted with a hydroxy-bearing component and 
a borate such as boric acid. 
##STR2## 
where R.sup.5 is a C.sub.1 -C.sub.30 hydrocarbyl group and optionally 
contains ester, amide or oxygen, nitrogen and/or sulfur groups, x is 1 to 
10, y and z are integers and y+z=3. 
The hydroxybearing compound can be a diol or mixture of diols such as 
1,2-dodecanediol, 1,2-hexadecanediol, 1,2-octadecandiol, glycerol 
monooleate, glycerol dioleate, glycerol monostearate, glycerol 
monomyristate, sorbitan monooleate, and similar hydroxyl-containing 
species. 
It is preferred to react the materials in the stochiometric ratios 
indicated in the previous equation although less than molar quantities or 
greater than molar quantities of a boronating agent can be use. Boric acid 
is the boronating agent of choice, although other boron compounds such as 
metaborates, trialkylborates or other suitable boronating agents can be 
employed. An excess of boronating agent can be used and is often 
preferred. 
The reaction are all conducted at a temperature between about -10.degree. 
C. and about 250.degree. C. for a period of between 1 and 48 hours. 
Preferably the reaction designated II above is conducted at a temperature 
of between -30.degree. C. and 60.degree. C. and the reaction designated 
III at 50.degree. C. to 250.degree. C. The desired reaction product 
separates as a liquid that can be then decanted from the remaining 
reaction mixture. In preparing the lubricant composition of this invention 
it desirable to use the additive in a concentration of between 0.001% and 
10% by weight of the total composition, although it is preferred to use 
between 0.1% to 3%. Greater concentrations can, of course, be used if such 
is desirable. 
Of particular significance is the ability of the additives of this 
invention to improve a variety of properties of a lubricant composition. 
They include the improved wear resistance or friction qualities of 
lubricated parts and improved resistance to oxidation and corrosion of 
oleaginous materials in lubricating media. These media preferably comprise 
liquid oils, in the form of either a mineral oil or a snythetic oil or 
mixtures thereof, but also may be a grease in which any of the 
aforementioned oils are employed as a vehicle. In general, mineral oils, 
both paraffinic, naphthenic and mixtures thereof, employed as the 
lubricant, or grease vehicle, may be of any suitable lubricating viscosity 
range, as for example, from about 45 SUS at 100.degree. F. to about 6000 
SUS at 100.degree. F., and preferably, from about 50 to about 250 SUS at 
210.degree. F. These oils may have viscosity indexes ranging to about 100 
or higher preferably from about 70 to about 95. The average molecular 
weights of these oils may range from about 250 to about 800. Where the 
lubricant is to be employed in the form of a grease, the lubricating oil 
is generally employed in an amount sufficient to balance the total grease 
composition, after accounting for the desired quantity of the thickening 
agent, and other additive components to be included in the grease 
formulation. A wide variety of thickening agents can be used in the grease 
of this invention. Included among the thickening agents are alkali and 
alkaline earth metal soaps of fatty acids and fatty materials having from 
about 12 to about 30 carbon atoms per molecule. The metals are typified by 
sodium, lithium, calcium and barium. Fatty materials are illustrated by 
stearic acid, hydroxystearic acid, stearin, cottonseed oil acids, oleic 
acid, palmitic acid, myristic acid and hydrogenated fish oils. Other 
thickening agents include salt and salt-soap complexes as calcium 
stearate-acetate (U.S. Pat. No. 2,197,263); barium stearate acetate (U.S. 
Pat. No. 2,564,561); calcium stearate-caprylate-acetate complexes (U.S. 
Pat. No. 2,999,065); calcium caprylate-acetate (U.S. Pat. No. 2,999,066); 
and calcium salts and soaps of low-, intermediate- and high-molecular 
weight acids and of nut oil acids. In general, grease thickeners may be 
employed which do not melt and dissolve when used at the required 
temperature within a particular environment; however, in all other 
respects, any material which is normally employed for thickening or 
gelling hydrocarbon fluids for forming grease can be used in preparing the 
aforementioned improved grease in accordance with the present invention. 
In instances where synthetic oils, or synthetic oils employed as the 
vehicle for the grease, are desired in preference to mineral oils, or in 
combination therewith, various compounds of this type may be successfully 
utilized. Typical synthetic vehicles include polyisobutylene, polybutenes, 
hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, 
trimethylol propane esters, neopentyl and pentaerythritol esters, 
di(2-ethylhexyl) sebacate, di(2-ethylhexyl) adipate, dibutyl phthalate, 
fluorocarbons, silicate esters, silanes, esters of phosphorus-containing 
acids, liquid ureas, ferrocene derivatives, hydrogenated synthetic oils, 
chain-type polyphenyls, siloxanes and silicones (polysiloxanes), 
alkyl-substituted diphenyl ethers typified by a butyl-substituted 
bis(p-phenoxy phenyl) ether, phenoxy phenylethers. 
It is to be understood that the compositions contemplated herein can also 
contain other materials. For example, other corrosion inhibitors, extreme 
pressure agents, anitwear agents, defoamants, detergents, dispersants, and 
the like can be used. These materials do not detract from the value of the 
compositions of this invention. Rather the materials serve to impart their 
customary properties to the particular compositions in which they are 
incorporated.

EXAMPLES 
Example 1 
Propoxylated Di-2-Ethylhexylphosphorodithioic Acid 
Approximately 708.6 grams of di-2-ethylhexylphosphorodithioic acid 
(Stauffer Chemical Company) was charged into a one-liter flask and 116.5 
grams (2.0 mole) propylene oxide were slowly added over a course of two 
hours. The reaction temperature was controlled at about or below 
40.degree. C. At the end of the addition, the color of the mixture changed 
from dark-green to light-yellow. The mixture weighed approximately 825 
grams. 
Example 2 
Borated Mixed Glycerol Monooleate/s-2 Hydroxypropyl 
O,O-di-2-Ethylhexylphosphorodithioate 
Approximately 178.1 grams of commercial glycerol monooleate (Stepan 
Company), 31 grams boric acid, 206 grams of the product from Example 1 and 
200 milliliters toluene were mixed in a one-liter, four-neck reactor 
equipped with thermometer, nitrogen gas sparger, Dean-Stark trap 
condenser, and agitator. The mixture was refluxed 
(113.degree..+-.2.degree. C.) over a period of three hours. A total volume 
of 22.8 milliliters of water was collected in the Dean-Stark trap. 
An additional hour of heating produced no more water of reaction. The 
toluene was removed by distillation leaving about 392 grams of 
low-viscosity brown liquid product. 
Example 3 
Borated Mixed Glycol Monooleate/Propoxylated 
O,O-di-2-Ethylhexylphosphorodithioate (Using Higher Boric Acid Charge) 
Approximately 178 grams glycerol monooleate, 93 grams boric acid, 206 grams 
of the product from Example 1 and 200 milliliters of toluene were mixed in 
a one-liter reactor with a nitrogen blanket. The mixture was heated and 
refluxed at 115.degree..+-.2.degree. C. over a course of 10 hours. A 
volume of 41.5 milliliters of water was collected in the Dean-Stark trap. 
Refluxing was continued for two more hours until H.sub.2 O evolution 
ceased. The mixture was diluted with 300 milliliter extra toluene when it 
had cooled to below 50.degree. C. The unreacted solids were then removed 
by filtration. The yellow-brown filtrate was returned to a reactor and 
toluene was removed under reduced pressure at 110.degree.-115.degree. C. A 
yield of 370 grams of brown liquid was obtained. 
The hydroxyester/phosphorodithioate-derived alcohol borates from the 
examples were blended into fully formulated oils and evaluated for 
oxidative stability. Basically, in the test the lubricant is subjected to 
a stream of air which is bubbled through at a rate of 5 liters per hour at 
325.degree. F. for 40 hours (Table 1), 260.degree. F. for 80 hours (Table 
2), and 375.degree. F. for 24 hours (Table 3). Present in the composition 
are samples of metals commonly used in engine construction, namely, iron, 
copper, aluminum and lead. See U.S. Pat. No. 3,682,980, incorporated 
herein by reference for further details of the test. Reductions in 
viscosity increase or limiting of neutralization number (or both) show 
effective control. 
TABLE 1 
______________________________________ 
CATALYTIC OXIDATION TEST 
Percent 
Additive Change in 
Conc. Kinematic 
Item (Wt. %) Viscosity Sludge 
______________________________________ 
Base Oil (150 second, fully 
0 30.61 Nil 
formulated, solvent refined 
paraffinic bright oil containing 
defoamant/demulsifier/antiwear/ 
anticorrosion/EP/antirust 
performance package 
Example 2 1.0 26.67 Nil 
______________________________________ 
TABLE 2 
______________________________________ 
CATALYTIC OXIDATION TEST 
Percent Percent 
Additive Change in Change in 
Conc. Acid Kinematic 
Item (Wt. %) Number Viscosity 
Sludge 
______________________________________ 
Base Oil (150 second, 
0 0.01 6.48 Nil 
fully formulated, 
solvent refined 
paraffinic bright oil 
containing defoamant/ 
demulsifier/antiwear/ 
anticorrosion/EP/ 
antirust 
performance package 
Example 2 1.0 0.11 6.46 Nil 
Example 3 1.0 -0.41 6.42 Nil 
______________________________________ 
TABLE 3 
______________________________________ 
CATALYTIC OXIDATION TEST 
Percent Percent 
Additive Change in Change in 
Conc. Acid Kinematic 
Item (Wt. %) Number Viscosity 
Sludge 
______________________________________ 
Base Oil (150 second, 
-- 6.53 177.9 Medium 
fully formulated, 
solvent refined 
paraffinic bright oil 
containing defoamant/ 
demulsifier/antiwear/ 
anticorrosion/EP/ 
antirust 
performance package 
Example 2 1.0 4.29 125.6 Light 
Example 3 1.0 4.08 101.2 Medium 
______________________________________ 
Table 4 below shows the improved wear resistance of these additives when 
tested in a Shell 4-ball wear tester. 
TABLE 4 
______________________________________ 
Four-Ball Test 
Wear Scar Diameter in MM, 30 Minute Test 
60 kg Load 
1000 2000 1000 2000 
RPM RPM RPM RPM 
Item 200.degree. F. 
200.degree. F. 
300.degree. F. 
300.degree. F. 
______________________________________ 
Base Oil (80% Solvent 
1.91 2.63 1.95 2.50 
Paraffinic Bright, 20% 
Solvent Paraffinic 
Neutral Mineral Oils) 
No additive from the Examples 
1% Example 2 in above 
0.77 1.13 0.86 1.15 
Base Oil 
1% Example 3 in above 
0.75 1.43 0.81 1.38 
Base Oil 
______________________________________ 
As an be seen from the above wear test results, the products described 
exhibit considerable antiwear activity.