N-Hydroxyalkyl pyrrolidinone esters as detergent compositions and lubricants and fuel containing same

Esters of hydroxyalkylpyrrolidinones and alkenylsuccinic anhydrides are effective detergent additives for hydrocarbyl lubricants and fuels.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to novel organic fluids containing minor amounts of 
hydroxyalkylpyrrolidinone esters useful as detergents, preferably in 
lubricants comprising oils of lubricating viscosity or greases prepared 
therefrom, fuels and functional fluids. 
2. Description of the Prior Art 
U.S. Pat. No. 3,155,685 describes the preparation of lactone-esters from 
half-esters of alkenylsuccinic anhydrides. It is also known to prepare 
such esters from alcohols and alkenylanhydrides. U.S. Pat. No. 4,029,675 
describes a continuous process for preparing lactone-esters from a 
branched-chain alkenylsuccinic anhydride and an alcohol or thiol. It is 
also known to react lactones and amines and thereafter esterify the 
product so produced with an alkenylsuccinic anhydride. However, there has 
been no previous disclosure of the present hydroxy pyrrolidinones or their 
use in lubricants or fuels known to applicant. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, novel compounds and novel 
hydrocarbyl fluids selected from the group consisting of lubricating oils, 
greases, liquid fuels and various functional fluids and a minor amount 
sufficient to impart detergent and/or dispersant properties thereto of a 
hydroxy pyrrolidinone prepared by (a) reacting a lactone such as 
butyrolactone with a hydroxyamine having one or more hydroxy substituents 
and (b) reacting the intermediate formed from (a) with an alkenylsuccinic 
anhydride. Equimolar ratios of a lactone and an amino alcohol are 
preferred for the reaction in (a), although a slight excess, e.g. from 
about 5 to about 10%, of amino alcohol may be used. The resultant 
hydroxyamino substituted pyrrolidinone is then reacted in step (b) in a 2 
to 1 molar ratio with an alkenylsuccinic anhydride to produce the desired 
hydroxy pyrrolidinone ester product. However, the molar ratios of the step 
(b) reactants may be varied respectively from about 1:1 to about 1:10 to 
produce polymeric products. The process may be briefly summarized with the 
following illustration: 
##STR1## 
where n is from 1 to 6, R is alkyl, cycloalkyl or aralkyl of 1 to 30 
carbons and P is a polymer such as polyisobutylene of C.sub.8 -C.sub.300. 
Temperatures of from 110.degree. to 300.degree. C. are used in reaction 
(a), preferably about 180.degree. to about 220.degree. C. Temperatures of 
from about 110.degree. to about 250.degree. C. are used in reaction (b), 
with the range of 140.degree. to about 180.degree. C. being preferred. It 
will be understood that the OH group or groups can be anywhere on the R 
group. Thus, the pyrrolidinone can also be represented as 
##STR2## 
where R.sub.1 and R.sub.2 are hydrogen alkyl, cycloalkyl, aralkyl or the 
OH-substituted members thereof. Together with the C linkage, they add up 
to the stated 1 to 30 carbon atoms for R. 
It is to be understood that other hydroxy-amino materials are formed and 
undoubtedly present during reaction (a) such as oxazolines or 
hydroxyamides which could, in similar manner to that shown for compound I, 
react with an alkyl or alkenylsuccinic anhydride to form esterified 
products. Accordingly the final product will consist substantially of 
compound III plus crude mixtures of other such reaction products. The 
ratios of I and II may be varied in any convenient ratio, e.g., from 1:1 
to 1:10 or more as stated previously to produce the additive, which may be 
monomeric, as in III, or polymeric, as in IIIA. The following equation is 
illustrative thereof: 
##STR3## 
where R is as defined above, n is equal to or greater than 2 and X 
indicates repeating polymer groups. It is noted, however, that the 
specification and the claims are not limited to the molar ratios of 
reactants illustrated in the exemplary equations. 
Suitable lactones include .gamma.-butyrolactone, .gamma.-valerolactone and 
alkyl, cycloalkyl, aryl and aralkyl substituted-butyrolactones. Especially 
preferred is .gamma.-butyrolactone. 
The hydroxy-substituted primary amines useful in this invention have the 
formula R--NH.sub.2, wherein R is a hydroxy-substituted hydrocarbyl group, 
preferably alkyl, and contains from 2 to 30 carbon atoms and from 1 to 6 
hydroxy groups. Preferably, the hydroxy primary amines contain from 2 to 
about 20 carbon atoms in a branched form and one or more of the branches 
contains hydroxy substituents. Hydroxy-substituted alkyl primary 
monoamines having up to three hydroxyl groups provide highly satisfactory 
products in accordance with this invention. As stated hereinabove, R may 
be alkyl, cycloalkyl or aralkyl, and R may also contain other 
substituents, such as sulfur, oxygen and the like and even additional 
amino groups. Alkyl and aralkyl sulfide groups and alkyl and aralkyl ether 
groups may also be present. Preferred hydroxyamines are the primary amines 
such as 2-aminoethanol, 3-aminopropanol, 2-amino-2-methylpropanol, D, 
L-2-amino-1-propanol, 2-(2-aminoethoxy)-ethanol and 
2-amino-2-ethyl-1-3-propanediol. These primary amines are well known in 
the art and can be prepared by conventional procedures or obtained 
commercially when available. 
Preferred alkenylsuccinic anhydrides are those conveniently prepared by 
reacting an olefin or a polymer or oligomer thereof having from 8 to about 
300 carbon atoms with maleic anhydride. However, any suitable procedure 
may be used to obtain alkenylsuccinic anhydrides useful in the present 
invention. Included among the preferred polymers useful in preparing the 
anhydride is polyisobutylene having a molecular weight in the range of 
about 300 to 3000. Such polymers are readily available through normal 
commercial channels or can be prepared by known methods. 
Of particular significance, in accordance with the present invention, is 
the ability of the compounds to improve the detergency of lubricating 
media which may comprise liquid hydrocarbon oils in the form of either a 
mineral oil or a synthetic oil, or in the form of a grease or other solid 
lubricant 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 
SSU at 100.degree. F. to about 6000 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. A wide variety of materials may be employed as 
thickening or gelling agents. These may include any of the conventional 
metal salts or soaps, which are dispersed in the lubricating vehicle in 
grease-forming quantities in such degree as to impart to the resulting 
grease composition the desired consistency. Other thickening agents that 
may be employed in the grease formulation may comprise the non-soap 
thickeners, such as surface-modified clays and silicas, aryl ureas, 
calcium complexes and similar materials. 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-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, phenoxy phenylethers, etc. 
It is to be understood, however, that the compositions contemplated herein 
can also contain other additive materials. For example, corrosion 
inhibitors, extreme pressure agents, viscosity index agents, antioxidants, 
anti-wear agents and the like can be used. These materials do not detract 
from the value of the compositions of this invention, rather these 
materials serve to impart their customary properties to the particular 
compositions in which they are incorporated. 
Of still further significance, is the detergency improvement of petroleum 
distillate fuel oils having an initial boiling point from about 75.degree. 
F. to about 135.degree. F. and an end boiling point from about 250.degree. 
F. to about 750.degree. F. It should be noted, in this respect, that the 
term "distillate fuel oils" is not intended to be restricted to 
straight-run distillate fractions. These distillate fuel oils can be 
straight-run distillate fuel oils, catalytically or thermally cracked 
(including hydrocracked) distillate fuel oils, naphthas and the like, with 
cracked distillate stocks. Moreover, such fuel oils can be treated in 
accordance with well-known commercial methods, such as acid or caustic 
treatment, hydrogenation, solvent-refining, clay treatment and the like. 
The distillate fuel oils are characterized by their relatively low 
viscosity and pour point. The principal property which characterizes these 
hydrocarbons, however, is their distillation range. As hereinbefore 
indicated, this range will lie between about 75.degree. F. and about 
750.degree. F. Obviously, the distillation range of each individual fuel 
oil will cover a narrower boiling range, falling nevertheless within the 
above-specified limits. Likewise, each fuel oil will boil substantially, 
continuously throughout its distillation range. 
Particularly contemplated among the fuel oils are Nos. 1, 2, and 3 fuel 
oils, used in heating and an diesel fuel oils, gasoline, turbine oil and 
jet combustion fuels. The fuel oils generally conform to the specification 
set forth in ASTM Specification D396-48T. Specifications for diesel fuels 
are defined in ASTM Specification D975-48T. Typical jet fuels are defined 
in Military Specification MIL-F-5624B. 
Functional fluids such as hydraulic fluids, heat exchange fluids, 
transmission fluids, and gear oils and marine diesel oils and fuels such 
as gasoline and fuel oil may advantageously use the additives of the 
present invention. Other additives may also be present in these 
compositions, such as additional detergents, viscosity improvement agents, 
extreme pressure additives and oxidation stability additives. These 
additional additives may be ash forming or non-ash forming, including 
alkenylsuccinimide of alkylene polyamines, metal sulfonates, metal 
phenates and metal phosphorodithioates. Notably the products of this 
invention produce no ash and are non-metallic. 
The compositions in accordance herewith may contain from 0.05% to about 20% 
by weight of the said additives and preferably from about 0.1 to 10%. 
Generally speaking the additives in accordance with the present invention 
may be effectively used in concentrations ranging from about 0.001 to 10 
wt. % with 0.05 to 5 wt. % being preferred.

DESCRIPTION OF SPECIFIC EMBODIMENTS 
The following data and examples serve to illustrate the marked degree in 
detergency improvement of organic media employing the aforementioned 
esters of hydroxy pyrrolidinones. It is understood, however, that the 
invention is not limited to the particular embodiments disclosed nor the 
specific compounds employed as detergent additives. Various modifications 
thereof can be employed and will be readily apparent to those skilled in 
the art. 
EXAMPLE 1 
Preparation of N-(2-hydroxyethyl)-2-pyrrolidinone is described by Puetzer 
et al., J. Am. Chem. Soc. 74, 4959 (1952). In essence, one mole of 
.gamma.-butyrolactone is reacted with one mole (or a slight excess) of 
2-aminoethanol with partial condensation to allow the water liberated to 
distill from the reactor. After 5-20 hours at 200.degree. C. an 88% yield 
of product after distillation is obtained. Unreacted starting materials 
can be recycled for high ultimate yields if desired. 
EXAMPLE 2 
In a procedure similar to that of Example 1, 2-amino-2-methylpropanol was 
reacted with .gamma.-butyrolactone resulting in a 59% yield of 
N-(1,1-dimethyl-2-hydroxyethyl)-2-pyrrolidinone, b.p. 175.degree./21 torr, 
after two cycles. The material melted at 56.degree.-58.degree. with 
.sup.13 CNMR peaks shifted 176.1, 69.7, 58.7, 46.3, 32.9, 23.2 and 18.2 
ppm from TMS. The elemental analyses agreed with the theoretical values 
for the expected compound. 
Found: C, 60.95%, H, 9.38%; N, 9.30%. Calc'd. C, 61.12%; H, 9.62%; N, 
8.91%. 
EXAMPLE 3 
3-aminopropanol reacted in similar manner to Example 2 with butyrolactone 
furnished a 78.6% yield of N-(3-hydroxypropyl)-2-pyrrolidinone, b.p. 
160.degree. C./3 torr. 
EXAMPLE 4 
2-(2-aminoethoxy)-ethanol reacted in the same manner as Example 1 yielded 
75% N-[(2-hydroxyethoxy)ethyl]-2-pyrrolidinone, b.p. 170.degree. C./2.5 
torr. 
EXAMPLE 5 
The reaction product of .gamma.-butyrolactone with 
2-amino-2-ethyl-1,3-propanediol reacted as in Example 1 was a dark, 
viscous material. The infrared absorption spectrum was similar to the 
other materials in the series with the expected peaks at 3375 cm.sup.-1 
(hydroxyl) and 1660 cm.sup.-1 (lactam). 
EXAMPLE 6 
From the reaction of D,L-2-amino-1-propanol with .gamma.-butyrolactone as 
in Example 1, a 78.6% yield of 
N-(1-methyl-2-hydroxyethyl)-2-pyrrolidinone, b.p. 142.degree. C./2.5 torr. 
Ester detergents in accordance with the present invention were prepared by 
reacting the hydroxy substituted pyrrolidinones described in certain of 
the above examples with alkenylsuccinic anhydrides in accordance with the 
equation denominated hereinabove as equation (b). 
EXAMPLE 7 
An alkenylsuccinic anhydride prepared from a commercial mixture of 
C.sub.18-24 olefins and maleic anhydride (75.5 g, 0.16 moles) was stirred 
with hydroxyethylpyrrolidinone (Example 1: 47.4 g, 0.37 moles) using a 
Barrett trap and azeotropic distillation with xylene to remove the water 
formed. When water collection ceased the solvent was removed under vacuum 
at 150.degree. C. 
EXAMPLES 8-10 
The ester detergents of these Examples were prepared like the ester of 
Example 7 except that the alkenylsuccinic anhydrides of Examples 8, 9 and 
10 were respectively prepared from a commercial C.sub.36 olefin (a dimer 
of the C.sub.18 -C.sub.24 mixture of Example 7), polyisobutylene having a 
molecular weight of 1300 and polyisobutylene having a molecular weight of 
900. 
EXAMPLES 11-12 
Additives of the present invention were prepared like the additive of 
Example 7, except that the hydroxy substituted pyrrolidinone used was that 
of Example 5. Also in Example 11 the alkenyl in the alkenylsuccinic 
anhydride was a 1300 weight polyisobutylene and in Example 12 it was a 
C.sub.36 olefin dimer of the C.sub.18 -C.sub.24 mixture used in Example 8. 
EXAMPLE 13 
In a manner identical to that of Example 7 a product was made by reacting 
together the pyrrolidinone of Example 2 and a 900 molecular weight 
polyisobutylenesuccinic anhydride. 
EXAMPLES 14-16 
In identical manner to that of Example 7 additives of the present invention 
were prepared with the exceptions as indicated in the Table. 
TABLE 
__________________________________________________________________________ 
Alkenylsuccinic 
Anhydride 
Pyrrolidinones 
##STR4## 
##STR5## Anhydride/Mole Ratio, 
Example No. 
where P is 
R.sub.1 
R.sub.2 Pyrrolidinone 
Hot Tube Rating 
__________________________________________________________________________ 
7 C.sub.18 H H 1/2 8 
8 C.sub.36 H H 1/2 8 
9 1300 PB H H 1/2 5+ 
10 900 PB H H 1/2 6 
11 1300 PB C.sub.2 H.sub.5 
CH.sub.2 OH 
1/2 6+ 
12 C.sub.36 C.sub.2 H.sub.5 
CH.sub.2 OH 
1/2 6+ 
13 900 PB CH.sub.3 
CH.sub.3 
1/2 8- 
14 900 PB C.sub.2 H.sub.5 
CH.sub.2 OH 
1/1 5+ 
15 800 PP CH.sub.3 
H 1/2 4+ 
16 1300 PB H H 1/2 6 
but the OH has been 
replaced by OCH.sub.2 CH.sub.2 OH 
__________________________________________________________________________ 
C.sub.18 is a mixture of 18-24+ carbon atoms 
C.sub.36 is a dimer of the above mixture 
900 and 1300 PB refer to the molecular weights of a polyisobutylene 
PP is polypropylene 
Several of the hydroxy pyrrolidinone esters of the foregoing examples were 
individually, 20 parts (non-oil basis), compounded with 947 parts solvent 
refined SAE 30 grade lubricating oil, 16 parts calcium sulfonate, 4 parts 
calcium phenate, 10 parts zinc alkyl-dithiophosphate and 1 part acrylic 
ester polymer and evaluated by the hot tube test described below. The 
results are shown in Table 1. If no detergent is used, the tube becomes 
completely clogged with particulate deposits and would have a rating of 
10. 
HOT TUBE TEST PROCEDURE 
Test oil and air are passed upward through a 2 mm capillary tube which is 
heated with an aluminum block. The test conditions are as follows: 
530.degree.-550.degree. F., 10 cc air/minute, 1/3 cc oil/hour, 16 hours. 
At the end of the test, the tubes are washed with hexane, then rated. A 
uniform lacquer is deposited in the tube and is rated on a scale of 0-10, 
with 0 being clean and 10 being heavy black deposits. 
As will be seen from the foregoing comparative data and results the 
compounds in accordance with the present invention impart markedly 
effective detergent properties to organic compositions. 
Although the present invention has been described with preferred 
embodiments, it is understood that various modifications and adaptations 
thereof may be made without departing from the spirit and scope of the 
invention as one of ordinary skill in the art will readily understand.