Oil-soluble adducts of benzotriazole and dialkylamines and lubricant compositions containing the same

Certain new adducts of benzotriazole and dialkylamines, the alkyl groups of which contain from 4 to 20 carbon atoms, are provided. Lubricant compositions having excellent anticorrosion characteristics are also provided when minor amounts of such adducts are added thereto.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a new addiitive composition constituting the 
reaction product adduct of benzotriazole and a specified dialkylamine. 
This invention further relates to lubricant compositions which normally 
cause or induce oxidative deterioration and/or corrosion of metallic 
surfaces with which said compositions are in contact. More particularly, 
in one of its aspects, the invention relates to lubricant compositions, 
particularly petroleum derived compositions, such as mineral lubricating 
oils, automotive oils, gear oils, transmission fluids, hydraulic fluids, 
way lubricants, heavy circulating oils, greases and other forms of 
lubricant compositions normally requiring the presence of anticorrosion 
additives and which contain a minor proportion of the aforenoted additive. 
2. Description of the Prior Art 
Prior to the present invention, benzotriazole has been employed in 
lubricants as a metal deactivator. Benzotriazole-maleic anhydride adducts 
have also been known and are disclosed in "Elisa Shigi and Franca Rocchi," 
Gass. Chim. Ital. 84, 183 (1955). It is found, however, that these adducts 
are not effective anticorrosion agents inasmuch as they are not 
oil-soluble. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, it has been found that 
anticorrosion properties can be effectively incorporated into lubricant 
compositions by including an anticorrosion amount of an adduct of 
benzotriazole and a specified dialkylamine. These adducts are soluble in 
organic compositions, such as the aforementioned lubricating oils, 
automotive oils, gear oils, transmission fluids, greases and other forms 
of lubricating compositions normally requiring the presence of 
anticorrosion additives and exhibit excellent anticorrosion properties. 
Therefore, the invention herein described and claimed is more particularly 
drawn to an adduct of benzotriazole and a dialkylamine prepared by 
reacting benzotriazole with a suitable dialkylamine and to a lubricant 
composition comprising a major proportion of an oil of lubricating 
viscosity or grease prepared therefrom and a minor amount sufficient to 
impart anticorrosion properties thereto of said adduct. 
The dialkylamines suitable herein include those having the general formula 
R.sub.1 R.sub.2 NH where R.sub.1 and R.sub.2 are alkyl groups of 4 to 20 
carbon atoms. The groups may be either identical or dissimilar, providing 
they contain a number of carbon atoms within the aforenoted range. Also, 
it is contemplated that R.sub.1 +R.sub.2 may be cycloalkyl, in which 
instance the cycloalkyl group may contain from 4 to 40 carbon atoms. Thus, 
the dialkylamines can be symmetrical such as dioctylamine or unsymmetrical 
such as heptyloctylamine. 
Exemplary of the dialkylamines useful in forming the described 
benzotriazole adduct are dioctylamine, didecylamine, didodecylamine and 
distearylamine. 
The adduct can be effectively employed in any amount which is useful for 
imparting the desired degree of anticorrosion properties. In many 
applications, the adduct is effectively employed in an amount from about 
0.001% to about 20%, by weight, and preferably in an amount from about 
0.5% to about 5%, by weight, of the total weight of the lubricant 
composition. 
In general, the adduct of benzotriazole and the specified dialkylamines are 
preferably reacted in a mole ratio of benzotriazole and dialkylamine of 
from about 1:1.5 to about 1:5. This reaction can be conducted at a 
temperature from about 80.degree. C., to about 150.degree. C. and 
preferably from about 90.degree. C. to about 110.degree. C. 
The above-described benzotriazole-dialkylamine adducts, as previously 
mentioned, may be incorporated in any lubricating media, which may 
comprise, for example, liquid lubricating oils. These oils may be in the 
form of either a mineral oil or a synthetic oil in the form of a grease in 
which any of the aforementioned oils are employed as a vehicle. In 
general, mineral oils, employed as the lubricating or grease vehicle, may 
be of any suitable lubricating viscosity range, as for example, from about 
45 SSU at 100.degree. F. to about 6,000 SSU at 100.degree. F., and, 
preferably, from about 50 to about 250 SSU at 210.degree. F. These oils 
may have viscosity indexes varying from below zero to about 100 or higher. 
Viscosity indexes from about 70 to about 95 are preferred. 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. 
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-ethyl hexyl) sebacate, di(2-ethyl hexyl) adipate, dibutyl phthalate, 
fluorocarbons, silicate esters, silanes, esters of phosphorous-containing 
acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, 
chain-type polyphenyls, siloxanes and silicones (polysiloxanes), 
alkyl-substituted diphenyl ethers typified by a butyl-substituted bis 
(p-phenoxy phenyl) ether, and phenoxy phenylethers.

DESCRIPTION OF SPECIFIC EMBODIMENTS 
The following examples and comparative data will serve to illustrate the 
novel adducts of the present invention and their anticorrosion properties 
in organic media, particularly lubricant compositions, containing them. 
EXAMPLE 1 
A mixture of di-n-octylamine (3 grams) and benzotriazole (1 gram) was 
stirred at 95.degree. C. for 5 minutes. The product was then tested for 
oil solubility and anticorrosion activity as described below. 
EXAMPLE 2 
The product was prepared and tested as described in Example 1, except that 
di-n-decylamine was substituted for di-n-octylamine. 
EXAMPLE 3 
The product was prepared and tested as described in Example 1, except that 
di-n-dodecylamine was substituted for di-n-octylamine. 
EXAMPLE 4 
The product was prepared and tested as described in Example 1, except that 
distearylamine was substituted for di-n-octylamine. 
EXAMPLE 5 
A mixture of di-n-octylamine (9 grams) and benzotriazole (1 gram) was 
stirred at 95.degree. C. for 5 minutes. The product was then tested for 
oil solubility as described below. 
EXAMPLE 6 
The product was prepared and tested as in Example 5 except that 
di-n-dodecylamine was substituted for di-n-octylamine. 
EXAMPLE 7 
The product was prepared and tested as in Example 5 except that 
distearylamine was substituted for di-n-octylamine. 
Solubility Tests 
The additives were tested for solubility in a 150 SUS solvent-refined 
mineral oil by measuring the time required to dissolve at 65.degree. C., 
and the time required for formation of haze at 25.degree. C. All additives 
were tested at the 0.1% benzotriazole level. A comparison with unreacted 
benzotriazole is shown in Table 1 below. 
Corrosion Tests 
Representative additives were then evaluated with respect to their 
abilities to protect copper and steel against corrosion by elemental 
sulfur in oil. The oil blend used for testing the aforementioned was an 
Arabian Light 150 SUS oil containing 50 ppm of elemental sulfur. The 
Modified ASLE-64-9 Corrosion Test was used. 
TABLE 1 
______________________________________ 
Solubilities of Additives 
in Lubricating Oils 
Time required to 
Time required to 
dissolve in oil 
form precipitate 
at 65.degree. C. 
or haze at 25.degree. C. 
Blend (in 150 SUS oil) 
(minutes) (hours) 
______________________________________ 
0.4% Example 1 6 &gt;23 
(0.1% benzotriazole) 
(0.3% di-n-octylamine) 
0.4% Example 2 5 &gt;23 
(0.1% benzotriazole) 
(0.3% di-n-decylamine) 
0.4% Example 3 4 &gt;23 
(0.1% benzotriazole) 
(0.3% di-n-dodecylamine) 
0.4% Example 4 4 &gt;23 
(0.1% benzotriazole) 
(0.3% distearylamine) 
(0.1% benzotriazole) &gt;168 
(0.9% di-n-octylamine) 
(0.1% benzotriazole) &gt;168 
(0.9% di-n-dodecylamine) 
1% Example 7 2 16 
(0.1% benzotriazole) 
(0.9% distearylamine) 
0.1% benzotriazole 
&gt;240 &gt;0.5 
______________________________________ 
MODIFIED ASLE-64-9 CORROSION TEST 
ASLE SLIDEWAY LUBRICANT ACCELERATED BREAKDOWN TEST 
Place clean polished pieces.sup.(1) of copper and carbon steel rods 
(approximate 0.25 inches diameter by 3.0 inches long) in a 100-cc Griffin 
beaker containing 35 to 40 grams of oil sample. Put beaker and contents 
into an electric drying oven for 24 hours, maintaining a temperature of 
210.degree..+-.2.degree. F. (99.degree..+-.1.degree. C.). Test period may 
be extended 72 hours, if necessary. 
FNT ( .sup.1 ) Test specimen pieces must be freshly polished and placed in 
pentane for &gt;30 minutes before using. These polished specimens must then 
be used within 30 minutes after the original 30-minute pentane 
deactivation period. 
Test results: 
Condition of Steel Rod 
Condition of Copper Rod 
Precipitate or Sludge 
Evaporation Loss % Wt. 
Specimens should be rated "as is" when removed from the oil (no washing); 
copper and steel rods are rated by comparing them and assigning the number 
from 1 (clean) to 10 (completely covered with corrosion) which most 
closely resembles their condition. 
TABLE 2 
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Corrosion Test Results 
Metal Specimen Rating 
Additive Copper Steel 
______________________________________ 
None 9 8 
0.02% Benzotriazole 
9 3 
0.04% Benzotriazole 
3 1 
0.08% Example 1 3 5 
(0.02% benzotriazole) 
(0.06% di-n-octylamine) 
0.08% Example 2 3 5 
(0.02% benzotriazole) 
(0.06% di-n-decylamine) 
0.08% Example 3 4 5 
(0.02% benzotriazole) 
(0.06% di-n-dodecylamine) 
0.08% Example 4 3 5 
(0.02% benzotriazole) 
(0.06% distearylamine) 
______________________________________ 
The data summarized in the Tables clearly establish that lubricant 
compositions of effective anticorrosion characteristics are provided when 
the reaction product of benzotriazole and a dialkylamine as defined herein 
are added in minor amounts thereto. 
It is apparent to those skilled in the art that the present invention has 
been described with reference to preferred emobidments and that departure 
therefrom can be effectively made and are within the scope of the 
specification.