Process for preparing polymeric dispersants having alternating polyalkylene and succinic groups

A process for preparing an oligomeric copolymer of an unsaturated acidic reactant and a high molecular weight olefin having a sufficient number of carbon atoms such that the resulting copolymer is soluble in lubricating oil and wherein at least 20 weight percent of the total olefin comprises an alkylvinylidene isomer, which process comprises reacting the high molecular weight olefin with the unsaturated acidic reactant in the presence of a solvent which comprises the reaction product of an unsaturated acidic reactant and a high molecular weight olefin.

BACKGROUND OF THE INVENTION 
The present invention relates to a process for preparing compositions which 
are useful as intermediates for dispersants used in lubricating oil 
compositions or as dispersants themselves. In addition, some of the 
compositions prepared by the present process are useful in the preparation 
of high molecular weight dispersants which have superior dispersant 
properties for dispersing sludge and varnish and superior Viton Seal 
compatibility. Such high molecular weight dispersants also advantageously 
impart fluidity modifying properties to lubricating oil compositions which 
are sufficient to allow elimination of some proportion of viscosity index 
improver from multigrade lubricating oil compositions which contain these 
dispersants. 
It is known in the art that alkenyl-substituted succinic anhydrides have 
been used as dispersants. Such alkenyl-substituted succinic anhydrides 
have been prepared by two different processes, a thermal process (see, 
e.g., U.S. Pat. No. 3,361,673) and a chlorination process (see, e.g., U.S. 
Pat. No. 3,172,892). The polyisobutenyl succinic anhydride ("PIBSA") 
produced by the thermal process has been characterized as a monomer 
containing a double bond in the product. Although the exact structure of 
chlorination PIBSA has not been definitively determined, the chlorination 
process PIBSA materials have been characterized as monomers containing 
either a double bond, a ring other than a succinic anhydride ring and/or 
chlorine in the product. [See J. Weill and B Sillion, "Reaction of 
Chlorinated Polyisobutene with Maleic Anhydride:Mechanism Catalysis by 
Dichloromaleic Anhydride", Revue de l'Institut Francais du Petrole, Vol. 
40, No. 1, pp. 77-89 (January-February, 1985).] Such compositions include 
one-to-one monomeric adducts (see, e.g., U.S. Pat. Nos. 3,219,666; 
3,381,022) as well as adducts having polyalkenyl-derived substituents 
adducted with at least 1.3 succinic groups per polyalkenyl-derived 
substituent (see, e.g., U.S. Pat. No. 4,234,435). 
In addition, copolymers of maleic anhydrides and some aliphatic 
alpha-olefins have been prepared. The polymers so produced were useful for 
a variety of purposes including dispersants for pigments and intermediates 
in the preparation of polyesters by their reaction with polyols or 
polyepoxides. However, olefins having more than about 30 carbon atoms were 
found to be relatively unreactive. (See, e.g., U.S. Pat. Nos. 3,461,108; 
3,560,455; 3,560,456; 3,560,457; 3,580,893; 3,706,704; 3,729,450; and 
3,729,451). 
Commonly assigned copending U.S. patent application Ser. No. 251,613, to 
James J. Harrison, filed Sep. 29, 1988, entitled "Novel Polymeric 
Dispersants Having Alternating Polyalkylene and Succnic Groups" discloses 
copolymers prepared by reacting an unsaturated acidic reactant, such as 
maleic anhydride, with a high molecular weight olefin, such as 
polyisobutene, in the presence of a free radical initiator, wherein at 
least about 20 percent of the total high molecular weight olefin comprises 
an alkylvinylidene isomer and wherein the high molecular weight olefin has 
a sufficient number of carbon atoms such that the resultng coolymer is 
soluble n lubricating oil. In U.S. Ser. No. 251,613, it is also taught 
that the reaction may be conducted neat or in the presence of a solvent in 
which the reactants and free radical initiator are soluble. Suitable 
solvents disclosed in U.S. Ser. No. 251,613 include liquid saturated or 
aromatic hydrocarbons having from 6 to 20 carbon atoms, ketones having 
from 3 to 5 carbon atoms and liquid saturated aliphatic dihalogenated 
hydrocarbons havng from 1 to 5 carbon atoms. Examples of solvents taught 
in U.S. Ser. No. 251,613 are acetone, tetrahydrofuran, chloroform, 
methylene chloride, dichloroethane, toluene, dioxane, chlorobenzene and 
xylene. 
The use of halogenated hydrocarbons as a solvent in the reaction of 
unsaturated acidic reactants, such as maleic anhydride, and high molecular 
weight olefins of the type described in U.S. Ser. No. 251,613 has a number 
of disadvantages. Such solvents are expensive, they are environmentally 
undesirable and they impede recycling of lubricating oils because of the 
residual halogen content. 
In the above-described reaction, the solvent is used primarily to 
solubilize the unsaturated acidic reactant, but also serves to reduce the 
viscosity of the reaction mixture. Unsaturated acidic reactants such as 
maleic anhydride are not very soluble in high molecular weight olefins at 
typical reaction temperatures of 50.degree. C. to 210.degree. C. When the 
unsaturated acidic reactant is maleic anhydride, it has been found that if 
the maleic anhydride forms a separate phase due to poor solubility, not 
only is the reaction rate negatively affected, but an undesirable resin or 
tar-like substance is formed which is believed to be polymaleic anhydride. 
Consequently, it would be highly advantageous to provide a process which 
avoids this condition, without having to resort to a halogenated 
hydrocarbon solvent. 
SUMMARY OF THE INVENTION 
The present invention is directed to a process for preparing an oligomeric 
copolymer of an unsaturated acidic reactant and a high molecular weight 
olefin having a sufficient number of carbon atoms such that the resulting 
copolymer is soluble in lubricating oil and wherein at least 20 weight 
percent of the total olefin comprises an alkylvinylidene isomer, which 
process comprises reacting the high molecular weight olefin with the 
unsaturated acidic reactant in the presence of a free radical initiator 
and a solvent which comprises the reaction product of an unsaturated 
acidic reactant and a high molecular weight olefin. Preferably, the 
solvent comprises (a) an oligomeric copolymer of an unsaturated acidic 
reactant and a high molecular weight olefin; or (b) a monomeric adduct of 
an unsaturated acidic reactant and a high molecular weight olefin in at 
least a one to one mole ratio of acidic reactant to olefin; or a mixture 
thereof. 
The copolymers produced by the present process have alternating succinic 
and polyalkylene groups. Suitable olefins for use in preparing these 
copolymers include those having about 32 carbon atoms or more, preferably 
having about 52 carbon atoms or more. Those preferred high molecular 
weight olefins include polyisobutenes. Especially preferred olefins for 
use in preparing the copolymer products are polyisobutenes having average 
molecular weights of from about 500 to about 5000 and in which the 
alkylvinylidene isomer comprises at least 50 percent of the total olefin. 
The copolymers prepared by the process of the invention are useful as 
dispersants themselves and also as intermediates in the preparation of 
other dispersant additives having improved dispersancy and/or detergency 
properties when employed in a lubricating oil. These copolymers are also 
advantageous because they do not contain double bonds, rings other than 
succinic anhydride rings, or chlorine (in contrast to thermal and 
chlorination PIBSAs) and as such have improved stability, as well as 
improved environmental properties due to the absence of chlorine. 
The copolymers produced by the instant process can also be used to form 
polysuccinimides which are prepared by reacting the copolymer with a 
polyamine to give a polysuccinimide. Such polysuccinimides include 
mono-polysuccinimides (where a polyamine component reacts with one 
succinic group); bispolysuccinimides (where a polyamine component reacts 
with a succinic group from each of two copolymer molecules, thus 
effectively cross-linking the copolymer molecules); and higher 
polysuccinimides (where a polyamine component reacts with a succinic group 
from each of greater than 2 copolymer molecules). These polysuccinimides 
are useful as dispersants and/or detergents in fuels and oils. In 
addition, these polysuccinimides have advantageous viscosity modifying 
properties, and may provide a viscosity index credit ("V.I. Credit") when 
used in lubricating oils, which may permit elimination of some portion of 
viscosity index improver ("V.I. Improver") from multigrade lubricating 
oils containing the same. 
In addition, such polysuccinimides can form a ladder polymeric structure or 
a cross-linked polymeric structure. These structures are advantageous 
because it is believed such structures are more stable and resistant to 
hydrolytic degradation and also to degradation by shear stress. 
Moreover, the copolymers prepared by the present process can be employed to 
make modified polysuccinimides wherein one or more of the nitrogens of the 
polyamine component is substituted with a hydrocarbyl oxycarbonyl, a 
hydroxyhydrocarbyl oxycarbonyl or a hydroxy poly(oxyalkylene)-oxycarbonyl. 
These modified polysuccinimides are improved dispersants and/or detergents 
for use in fuels or oils. 
Accordingly, the copolymers made by the present process are useful in 
providing a lubricating oil composition comprising a major amount of an 
oil of lubricating viscosity and an amount of a copolymer, polysuccinimide 
or modified succinimide additive sufficient to provide dispersancy and/or 
detergency. These additives may also be formulated in lubricating oil 
concentrates which comprise from about 90 to about 50 weight percent of an 
oil of lubricating viscosity and from about 10 to about 50 weight percent 
of the additive. 
Furthermore, the copolymers formed by the present process can be used to 
provide a fuel composition comprising a major portion of a fuel boiling in 
a gasoline or diesel range and an amount of copolymer, polysuccinimide or 
modified succinimide additives sufficient to provide dispersancy and/or 
detergency. These additives can also be used to make fuel concentrates 
comprising an inert stable oleophilic organic solvent boiling in the range 
of about 150.degree. F to about 400.degree. F and from about 5 to about 50 
weight percent of such additive. 
DEFINITIONS 
As used herein, the following terms have the following meanings unless 
expressly stated to the contrary. The term "unsaturated acidic reactants" 
refers to maleic or fumaric reactants of the general formula: 
##STR1## 
wherein X and X' are the same or different, provided that at least one of 
X and X' is a group that is capable of reacting to esterify alcohols, form 
amides or amine salts with ammonia or amines, form metal salts with 
reactive metals or basically reacting metal compounds and otherwise 
function as acylating agents. Typically, X and/or X' is --OH, 
--O--hydrocarbyl, --OM.sup.+ where M.sup.+ represents one equivalent of a 
metal, ammonium or amine cation, --NH.sub.2, --Cl, --Br, and taken 
together X and X' can be --O-- so as to form an anhydride. Preferably X 
and X' are such that both carboxylic functions can enter into acylation 
reactions. Maleic anhydride is a preferred unsaturated acidic reactant. 
Other suitable unsaturated acidic reactants include electron-deficient 
olefins such as monophenyl maleic anhydride; monomethyl, dimethyl, 
monochloro, monobromo, monofluoro, dichloro and difluoro maleic anhydride; 
N-phenyl maleimide rnd other substituted maleimides; isomaleimides; 
fumaric acid, maleic acid, alkyl hydrogen maleates and fumarates, dialkyl 
fumarates and maleates, fumaronilic acids and maleanic acids; and 
maleonitrile, and fumaronitrile. 
The term "alkylvinylidene" or "alkylvinylidene isomer" refers to high 
molecular weight olefins and polyalkylene components having the following 
vinylidene structure 
##STR2## 
wherein R is alkyl or substituted alkyl of sufficient chain length to give 
the resulting molecule solubility in lubricating oils and fuels, thus R 
generally has at least about 30 carbon atoms, preferably at least about 50 
carbon atoms and R.sub. v is lower alkyl of about 1 to about 6 carbon 
atoms. 
The term "soluble in lubricating oil" refers to the ability of a material 
to dissolve in aliphatic and aromatic hydrocarbons such as lubricating 
oils or fuels in essentially all proportions. 
The term "high molecular weight olefins" refers to olefins (including 
polymerized olefins having a residual unsaturation) of sufficient 
molecular weight and chain length to lend solubility in lubricating oil to 
their reaction products. Typically olefins having about 32 carbons or 
greater (preferably olefins having about 52 carbons or more) suffice. 
The term "high molecular weight polyalkyl" refers to polyalkyl groups of 
sufficient molecular weight and hydrocarbyl chain length that the products 
prepared having such groups are soluble in lubricating oil. Typically 
these high molecular weight polyalkyl groups have at least about 30 carbon 
atoms, preferably at least about 50 carbon atoms. These high molecular 
weight polyalkyl groups may be derived from high molecular weight olefins. 
The term "PIBSA" is an abbreviation for polyisobutenyl succinic anhydride. 
The term "polyPIBSA" refers to a class of copolymers within the scope of 
the present invention which are copolymers of polyisobutene and an 
unsaturated acidic reactant which have alternating succinic groups and 
polyisobutyl groups. PolyPIBSA has the general formula 
##STR3## 
wherein n is one or greater; R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are 
selected from hydrogen, methyl and polyisobutyl having at least about 30 
carbon atoms (preferably at least about 50 carbon atoms) wherein either 
R.sub.1 and R.sub.2 are hydrogen and one of R.sub.3 and R.sub.4 is methyl 
and the other is polyisobutyl, or R.sub.3 and R.sub.4 are hydrogen and one 
of R.sub.1 and R.sub.2 is methyl and the other is polyisobutyl. 
The term "PIBSA number" refers to the anhydride (succinic group) content of 
polyPIBSA on a 100% actives basis. The PIBSA number is calculated by 
dividing the saponification number by the percent polyPIBSA in the 
product. The units are mg KOH per gram sample. 
The term "succinic group" refers to a group having the formula 
##STR4## 
wherein W and Z are independently selected from the group consisting of 
--OH, --Cl, --O-- lower alkyl or taken together are --O-- to form a 
succinic anhydride group. The term "--O-- lower alkyl" is meant to include 
alkoxy of 1 to 6 carbon atoms. 
The term "degree of polymerization" expresses the length of a linear 
polymer an refers to the number of repeating (monomeric) units in the 
chain. The average molecular weight of a polymer is the product of the 
degree of polymerization and the average molecular weight of the repeating 
unit (monomer). Accordingly, the average degree of polymerization is 
calculated by dividing the average molecular weight of the polymer by the 
average molecular weight of the repeating unit. 
The term "polysuccinimide" refers to the reaction product of a copolymer 
made by the present process with polyamine.

DETAILED DESCRIPTION OF THE INVENTION 
A. Copolymer 
The copolymers made by the present process are prepared by reacting a high 
molecular weight olefin wherein at least about 20% of the total olefin 
composition comprises the alkylvinylidene isomer and an unsaturated acidic 
reactant in the presence of a free radical initiator and a solvent 
comprising the reaction product of an unsaturated acidic reactant and a 
high molecular weight olefin. Preferably, the solvent comprises (a) an 
oligomeric copolymer of an unsaturated acidic reactant and a high 
molecular weight olefin or (b) a monomeric adduct of an unsaturated acidic 
reactant and a high molecular weight olefin in at least a one to one mole 
ratio of acidic reactant to olefin; or a mixture thereof. Suitable high 
molecular weight olefins have a sufficient number of carbon atoms so that 
the resulting copolymer is soluble in lubricating oil and thus have on the 
order of about 32 carbon atoms or more. Preferred high molecular weight 
olefins are polyisobutenes and polypropylenes. Especially preferred are 
polyisobutenes, particularly preferred are those having a molecular weight 
of about 500 to about 5000, more preferably about 900 to about 2500. 
Preferred unsaturated acidic reactants include maleic anhydride. 
Since the high molecular weight olefins used in the process of the present 
invention are generally mixtures of individual molecules of different 
molecular weights, individual copolymer molecules resulting will generally 
contain a mixture of high molecular weight polyalkyl groups of varying 
molecular weight. Also, mixtures of copolymer molecules having different 
degrees of polymerization will be produced. 
The copolymers made by the process of the present invention have an average 
degree of polymerization of 1 or greater, preferably from about 1.1 to 
about 20, and more preferably from about 1.5 to about 10. 
In accordance with the process of the present invention, the desired 
copolymer products are prepared by reacting a "reactive" high molecular 
weight olefin in which a high proportion of unsaturation, at least about 
20% , is in the alkylvinylidene configuration, e.g., 
##STR5## 
wherein R and R.sub.v are as previously defined in conjunction with 
Formula III, with an unsaturated acidic reactant in the presence of a free 
radical initiator and an oligomeric or monomeric solvent as described 
above. The product copolymer has alternating polyalkylene and succinic 
groups and has an average degree of polymerization of 1 or greater. 
The copolymers prepared by the instant process have the general formula: 
##STR6## 
wherein W' and Z' are independently selected from the group consisting of 
--OH, --O-- lower alkyl or taken together are --O-- to form a succinic 
anhydride group, n is one or greater; and R.sub.1, R.sub.2, R.sub.3 and 
R.sub.4 are selected from hydrogen, lower alkyl of 1 to 6 carbon atoms, 
and high molecular weight polyalkyl wherein either R.sub.1 and R.sub.2 are 
hydrogen and one of R.sub.3 and R.sub.4 is lower alkyl and the other is 
high molecular weight polyalkyl, or R.sub.3 and R.sub.4 are hydrogen and 
one of R.sub.1 and R.sub.2 is lower alkyl and the other is high molecular 
weight polyalkyl. 
In a preferred embodiment, when maleic anhydride is used as the unsaturated 
acidic reactant, the reaction produces copolymers predominately of the 
following formula: 
##STR7## 
wherein n is about 1 to about 100, preferably about 2 to about 20, more 
preferably 2 to 10, and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are selected 
from hydrogen, lower alkyl of about 1 to 6 carbon atoms and higher 
molecular weight polyalkyl, wherein either R.sub.1 and R.sub.2 are 
hydrogen and one of R.sub.3 and R.sub.4 is lower alkyl and the other is 
high molecular weight polyalkyl or R.sub.3 and R.sub.4 are hydrogen and 
one of R.sub.1 and R.sub.2 is lower alkyl and the other is high molecular 
weight polyalkyl. 
Preferably, the high molecular weight polyalkyl group has at least about 30 
carbon atoms, preferably at least about 50 carbon atoms. Preferred high 
molecular weight polyalkyl groups include polyisobutyl groups. Preferred 
polyisobutyl groups include those having average molecular weights of 
about 500 to about 5000, more preferably from about 900 to about 2500. 
Preferred lower alkyl groups include methyl and ethyl; especially 
preferred lower alkyl groups include methyl. 
Generally, such copolymers contain an initiator group, I, and a terminator 
group, T, as a result of the reaction with the free radical initiator used 
in the polymerization reaction. In such a case, the initiator and 
terminator groups may be 
##STR8## 
where R.sub.7 is hydrogen, alkyl, aryl, alkaryl, cycloalkyl, alkoxy, 
cycloalkoxy, acyl, alkenyl, cycloalkenyl, alkynyl; or alkyl, aryl or 
alkaryl optionally substituted with 1 to 4 substituents independently 
selected from nitrile, keto, halogen, nitro, alkyl, aryl, and the like. 
Alternatively, the initiator group and/or terminator group may be derived 
from the reaction product of the initiator with another material, such as 
solvent. 
The copolymers prepared by the present process differ from the PIBSAs 
prepared by the thermal process in that the thermal process products 
contain a double bond and a singly substituted succinic anhydride group, 
that is, a monomeric one to one adduct. The copolymers prepared by the 
present process differ from the PIBSAs prepared by the chlorination 
process, since those products contain a double bond, a ring other than a 
succinic anhydride ring, or one or more chlorine atoms. 
The copolymers prepared by the present process contain no double bonds, 
rings other than succinic anhydride rings, or chlorine atoms. In addition, 
the succinic anhydride groups are doubly substituted (i.e., have two 
substituents, one of which may be hydrogen) at the 2- and 3-positions, 
that is: 
##STR9## 
A(1) High Molecular Weight Polyalkylene Group 
The high molecular weight polyalkyl group is derived from a high molecular 
weight olefin. The high molecular weight olefins used in the preparation 
of the instant copolymers are of sufficiently long chain length so that 
the resulting composition is soluble in and compatible with mineral oils, 
fuels and the like; and the alkylvinylidene isomer of the high molecular 
weight olefin comprises at least about 20% of the total olefin 
composition. 
Such high molecular weight olefins are generally mixtures of molecules 
having different molecular weights and can have at least one branch per 6 
carbon atoms along the chain, preferably at least one branch per 4 carbon 
atoms along the chain, and particularly preferred that there be about one 
branch per 2 carbon atoms along the chain. These branched chain olefins 
may conveniently comprise polyalkenes prepared by the polymerization of 
olefins of from 3 to 6 carbon atoms, and preferably from olefins of from 3 
to 4 carbon atoms, and more preferably from propylene or isobutylene. The 
addition-polymerizable olefins employed are normally 1-olefins. The branch 
may be of from 1 to 4 carbon atoms, more usually of from 1 to 2 carbon 
atoms and preferably methyl. 
The preferred alkylvinylidene isomer comprises a methyl- or ethylvinylidene 
isomer, more preferably the methylvinylidene isomer. 
The especially preferred high molecular weight olefins used to prepare the 
instant copolymers are polyisobutenes which comprise at least about 20% of 
the more reactive methylvinylidene isomer, preferably at least 50% and 
more preferably at least 70% . Suitable polyisobutenes include those 
prepared using BF.sub.3 catalysis. The preparation of such polyisobutenes 
in which the methylvinylidene isomer comprises a high percentage of the 
total composition is described in U.S. Pat. Nos. 4,152,499 and 4,605,808. 
Polyisobutenes produced by conventional AlCl.sub.3 catalysis when reacted 
with unsaturated acidic reactants, such as maleic anhydride, in the 
presence of a free radical initiator, produce products similar to thermal 
PIBSA in molecular weight and thus do not produce a copolymeric product. 
Preferred are polyisobutenes having average molecular weights of about 500 
to about 5000. Especially preferred are those having average molecular 
weights of about 900 to about 2500. 
A(2) Unsaturated Acidic Reactant 
The unsaturated acidic reactant used in the preparation of the instant 
copolymers comprises a maleic or fumaric reactant of the general formula: 
##STR10## 
wherein X and X' are the same or different, provided that at least one of 
X and X' is a group that is capable of reacting to esterify alcohols, form 
amides or amine salts with ammonia or amines, form metal salts with 
reactive metals or basically reacting metal compounds and otherwise 
function to acylate. Typically, X and/or X' is --OH, --O--hydrocarbyl, 
--OM.sup.+ where M.sup.+ represents one equivalent of a metal, ammonium or 
amine cation, --NH.sub.2, --Cl, --Br, and taken together X and X.sup.- 
can be --O-- so as to form an anhydride. Preferably, X and X' are such 
that both carboxylic functions can enter into acylation reactions. 
Preferred are acidic reactants where X and X' are each independently 
selected from the group consisting of --OH, --Cl, --O-- lower alkyl and 
when taken together, X and X' are --O--. Maleic anhydride is the preferred 
acidic reactant. Other suitable acidic reactants include 
electron-deficient olefins such as monophenyl maleic anhydride; 
monomethyl, dimethyl, monochloro, monobromo, monofluoro, dichloro and 
difluoro maleic anhydride; N-phenyl maleimide and other substituted 
maleimides; isomaleimides; fumaric acid, maleic acid, alkyl hydrogen 
maleates and fumarates, dialkyl fumarates and maleates, fumaronilic acids 
and maleanic acids; and maleonitrile, and fumaronitrile. 
Preferred unsaturated acidic reactants include maleic anhydride, and maleic 
acid. The particularly preferred acidic reactant is maleic anhydride. 
A(3) General Preparation of Copolymer 
As noted above, the copolymers made by the process of the invention are 
prepared by reacting a reactive high molecular weight olefin and an 
unsaturated acidic reactant in the presence of a free radical initiator 
and a specific solvent, as described herein. 
As discussed above, in U.S. patent application Ser. No. 251,613 it is 
taught that the reaction of high molecular weight olefin and unsaturated 
acidic reactant in the presence of a free radical initiator may be 
conducted neat or with a solvent, such as a saturated or aromatic 
hydrocarbon, a ketone or a liquid saturated aliphatic dihalogenated 
hydrocarbon. 
It has now been found that when this reaction is carried out neat, that is, 
in the absence of any solvent, a significant amount of resin is formed, 
presumably from polymerization of the unsaturated acidic reactant. 
This problem can be somewhat avoided by employing a halogenated hydrocarbon 
solvent, but the use of such solvents also has certain drawbacks. 
Halogenated hydrocarbon solvents are both expensive and environmentally 
undesirable. Moreover, they impede the recycling of lubricating oils 
because of the residual halogen content. 
It has now been discovered that oligomeric copolymers of high molecular 
weight olefins and unsaturated acidic reactants can be prepared in 
improved yields by employing a solvent which comprises the reaction 
product of an unsaturated acidic reactant and a high molecular weight 
olefin. Preferably, the solvent comprises either (a) an oligomeric 
copolymer of an unsaturated acidic reactant and a high molecular weight 
olefin or (b) a monomeric adduct of an unsaturated acidic reactant and a 
high molecular weight olefin in at least a one-to-one mole ratio of acidic 
reactant to olefin. Mixtures of (a) and (b) may also be employed as the 
solvent. 
For use as a solvent, the oligomeric copolymer of unsaturated acidic 
reactant and high molecular weight olefin can be conveniently obtained by 
retaining a portion of the oligomeric copolymer product from a previous 
run. Alternatively, the solvent may be a monomeric adduct of an 
unsaturated acidic reactant and a high molecular weight olefin in at least 
a 1:1 ratio of acid to olefin, which can be readily prepared via the known 
"thermal process" or the known "chlorination process", as described above. 
For use in preparing the monomeric adduct, the high molecular weight 
olefin may contain less than 20% of the alkylvinylidene isomer. 
Preferred solvents include the oligomeric copolymer product of maleic 
anhydride and polyisobutene, that is, "polyPIBSA", as defined above, and 
the monomeric adduct of maleic anhydride and polyisobutene, namely, 
polyisobutenyl succinic anhydride or "PIBSA". A particularly preferred 
solvent is polyPIBSA. 
The "thermal" PIBSA described above is well known in the art. One method of 
preparing thermal PIBSA is disclosed in U.S. Pat. No. 3,361,673, the 
disclosure of which is incorporated herein by reference for its teachings 
on preparing thermal PIBSA. The "chlorination process" PIBSA described 
above is also well known in the art. One method of preparing chlorination 
process PIBSA is disclosed in U.S. Pat. No. 3,172,892, the disclosure of 
which is incorporated herein by reference for its teachings in preparing 
chlorination process PIBSA. 
The amount of solvent employed should be such that it can dissolve the 
acidic reactant and the high molecular weight olefin, in addition to the 
resulting copolymers. The volume ratio of solvent to high molecular weight 
olefin is suitably between 1:1 and 100:1, and is preferably between 1.5:1 
and 4:1. 
The reaction may be conducted at a temperature in the range of about 
90.degree. C. to about 210.degree. C., and preferably from about 
130.degree. C. o about 150.degree. C. Reaction at lower temperatures works 
to a point, but the reaction solution generally becomes viscous and 
therefore requires added heat to obtain satisfactory reaction. Although 
not wishing to be bound by any theory, it is believed that there is a 
so-called "cage-effect", wherein the free radical initiator is trapped in 
the solvent/reaction mixture and therefore cannot effectively initiate the 
polymerization reaction. 
Although it has been observed that reaction may be slow or incomplete below 
the preferred temperature range of about 130.degree. C. to 150.degree. C., 
it is envisioned that stepping the reaction temperature up in increments 
from a minimum of about 90.degree. C. could provide advantageous results. 
The highest temperature of these incremental temperature steps is 
preferably above about 140.degree. C. when complete reaction is desired. 
In general, the copolymerization process of the present invention can be 
initiated by any free radical initiator. Such initiators are well known in 
the art. However, the choice of free radical initiator may be influenced 
by the reaction temperature employed. 
The preferred free-radical initiators are the peroxide-type polymerization 
initiators and the azo-type polymerization initiators. Radiation can also 
be used to initiate the reaction, if desired. 
The peroxide-type free-radical initiator can be organic or inorganic, the 
organic having the general formula: R.sub.3 OOR.sub.3 ' where R.sub.3 is 
any organic radical and R.sub.3 ' is selected from the group consisting of 
hydrogen and any organic radical. Both R.sub.3 and R.sub.3 ' can be 
organic radicals, preferably hydrocarbon, aroyl, and acyl radicals, 
carrying, if desired, substituents such as halogens, etc. Preferred 
peroxides include di-tert-butyl peroxide, tert-butyl peroxybenzoate, and 
dicumyl peroxide. 
Examples of other suitable peroxides, which in no way are limiting, include 
benzoyl peroxide; lauroyl peroxide; other tertiary butyl peroxides; 
2,4-dichlorobenzoyl peroxide; tertiary butyl hydroperoxide; cumene 
hydroperoxide; diacetyl peroxide; acetyl hydroperoxide; 
diethylperoxycarbonate; tertiary butyl perbenzoate; and the like. 
The azo-type compounds, typified by alpha,alpha'-azo-bisisobutyronitrile, 
are also well-known free-radical promoting materials. These azo compounds 
can be defined as those having present in the molecule group --N=N wherein 
the balances are satisfied by organic radicals, at least one of which is 
preferably attached to a tertiary carbon. Other suitable azo compounds 
include, but are not limited to, p-bromobenzenediazonium fluoborate; 
p-tolyldiazoaminobenzene; p-bromobenzenediazonium hydroxide; azomethane 
and phenyldiazonium halides. A suitable list of azo-type compounds can be 
found in U.S. Pat. No. 2,551,813, issued May 8, 1951 to Paul Pinkney. 
The amount of initiator to employ, exclusive of radiation, of course, 
depends to a large extent on the particular initiator chose, the high 
molecular olefin used and the reaction conditions. The initiator must, of 
course, be soluble in the reaction medium. The usual concentrations of 
initiator are between 0.001:1 and 0.2:1 moles of initiator per mole of 
acidic reactant, with preferred amounts between 0.005:1 and 0.10:1. 
In carrying out the process of the invention, a single free radical 
initiator or a mixture of free radical initiators may be employed. The 
initiator may also be added over time. For example, it may be desirable to 
add an initiator having a low decomposition temperature as the mixture is 
warming to reaction temperature, and then add an initiator having a higher 
decomposition temperature as the mixture reaches higher reaction 
temperatures. Alternatively, a combination of initiators could both be 
added prior to heating and reaction. In this case, an initiator having a 
high decomposition temperature would initially be inert, but would later 
become active as the temperature rose. 
The reaction pressure should be sufficient to minimize losses of acidic 
reactant to the vapor phase. Pressures can therefore vary between about 
atmospheric and 100 psig or higher, but the preferred pressure is 
atmospheric. 
The reaction time is usually sufficient to result in the substantially 
complete conversion of the acidic reactant and high molecular weight 
olefin to copolymer. The reaction time is suitable between one and 24 
hours, with preferred reaction times between two and ten hours. 
As noted above, the subject reaction is a solution-type polymerization 
reaction. The high molecular weight olefin, acidic reactant, solvent and 
initiator can be brought together in any suitable manner. The important 
factors are intimate contact of the high molecular weight olefin and 
acidic reactant in the presence of a free-radical producing material. 
Although the following description shows the use of polyisobutene (PIB), 
maleic anhydride (MA) and polyisobutenyl succinic anhydride (PIBSA), it is 
intended to be merely exemplary and the disclosure is intended to apply 
equally well to other high molecular weight olefins, unsaturated acidic 
reactants and the reaction products therefrom. Moreover, the following 
exemplary polyPIBSA disclosure is intended to apply equally well to the 
copolymer reaction product of any of the unsaturated acidic reactants and 
high molecular weight olefins described herein. 
The reaction can be run either batchwise or continuously. The reaction 
temperature range is about 90.degree. C. to 210.degree. C. and preferably 
about 130.degree. C. to 150.degree. C. The reactor temperature effects the 
molecular weight distribution, and this can influence the ratio of maleic 
anhydride to polybutene that is fed to the reactor. Theoretically the 
maleic anhydride charge can range from 1 to 2 moles of maleic anhydride 
per mole of methyl vinylidene isomer of PIB. Typically, the free radical 
initiator is charged at 0.1 moles initiator per 1.0 moles maleic 
anhydride, although this can vary. The reaction can be carried out at 
atmospheric pressure, although at the higher temperature range it may be 
desirable to pressurize the reactor slightly (i.e., 10 psig) to suppress 
the loss of maleic anhydride to the vapor phase. Neutral oil can be used 
to reduce the viscosity of the mixture, but this can be deleterious to the 
reaction rate and productivity of the reactor. 
If the reaction is run batchwise, PIB and polyPIBSA from a previous run are 
charged to the reactor. Thermal process PIBSA or chlorination process 
PIBSA may also be used in lieu of or in addition to polyPIBSA. The ratio 
of PIB to polyPIBSA should be such as to assure complete solubility of 
maleic anhydride in the mixture at reaction conditions. If polyPIBSA is 
not added at a sufficient level so as to maintain total maleic anhydride 
solubility, the rate of reaction can be negatively affected, and the 
formation of resin may be likely. To maximize reactor productivity, the 
minimum amount of polyPIBSA that is necessary to maintain total solubility 
of the maleic anhydride charge should be used. The reactor is stirred and 
heated to the desired reaction temperature, and the maleic anhydride and 
free radical initiator are added at the appropriate time/times during this 
step. Reaction times will vary with temperature, concentration of 
reactants, and types of free radical initiators. Reactions performed at 
140.degree. C., for example, were nearly complete according to .sup.13 C 
NMR in roughly two hours. When the reaction is complete, removal of any 
unreacted maleic anhydride can be accomplished by increasing the reactor 
temperature to 150.degree. C. to 250.degree. C., preferably 180.degree. C. 
to 200.degree. C., while applying sufficient vacuum. This procedure also 
tends to decompose any remaining free radical initiator. Another method 
for removal of unreacted maleic anhydride is the addition of a solvent 
(e.g., hexane) which solubilizes the polyPIBSA and precipitates the maleic 
anhydride. The mixture then is filtered to remove the maleic anhydride 
followed by stripping to remove the solvent. 
If the reaction is run continuously, a continuous stirred tank reactor 
(CSTR) or series of such reactors can be used. Reaction conditions should 
be selected to maintain the bulk concentration of polyPIBSA at a 
sufficient level to maintain maleic anhydride solubility in the reactor or 
series of reactors. A continuous reactor is thought to be particularly 
advantageous for reactions carried out at the lower temperature range. As 
the temperature is reduced, the maleic anhydride solubility in the 
polyPIBSA/polybutene mixture decreases and this necessitates that the 
polyPIBSA concentration be increased or the maleic anhydride concentration 
be decreased so that total solubility of the maleic anhydride is 
maintained. In a batch process an increase in the initial charge of 
polyPIBSA can result in a decrease in reactor productivity. Likewise, 
decreasing the maleic anhydride charge or extending the addition of maleic 
anhydride over a time period can decrease reactor productivity. On the 
other hand, in a CSTR at steady state conditions the polyPIBSA 
concentration in the bulk mixture is not only constant, but it is 
essentially the same the product exiting the reactor. Therefore, the 
polyPIBSA concentration in a CSTR is at a maximum (equal to the polyPIBSA 
product for a single stage CSTR) when compared to a simple batch process 
where the all polybutene is charged at the beginning of the reaction and 
the polyPIBSA concentration is at a minimum. 
For the continuous reactor, the temperature can range from 90.degree. C. to 
210.degree. C. and preferably from 130.degree. C. to 150.degree. C. PIB, 
maleic anhydride, and free-radical initiator can be fed continuously at 
appropriate rates so as to maintain a certain level of conversion of the 
reactants to polyPIBSA. It is envisioned that the product stream from the 
reactor then is heated to a temperature in the range of 150.degree. C. to 
250.degree. C. and preferably in the range from 180.degree. C. to 
200.degree. C. to strip off any unreacted maleic anhydride and to 
decompose any remaining free-radical initiator. Vacuum can also be sued to 
facilitate removal of the unreacted maleic anhydride. It is envisioned 
that a wiped film evaporator or similar types of equipment may be suitable 
for this type of operation. 
In one envisioned embodiment, the reaction product of an unsaturated acidic 
reactant and a high molecular weight, high vinylidene-containing olefin is 
further reacted thermally. In this embodiment, any unreacted olefin, 
generally the more hindered olefins, i.e., the non-vinylidene, that do not 
react readily with the unsaturated acidic reactant under free radical 
conditions are reacted with unsaturated acidic reactant under thermal 
conditions, i.e., at temperatures of about 180.degree. to 280.degree. C. 
These conditions are similar to those used for preparing thermal PIBSA. 
The reaction solvent, as noted above, must be one which dissolves both the 
acidic reactant and the high molecular weight olefin. It is necessary to 
dissolve the acidic reactant and high molecular weight olefin so as to 
bring them into intimate contact in the solution polymerization reaction. 
It has been found that the solvent must also be one in which the resultant 
copolymers are soluble. 
It has been found that a small amount of haze or resin, typically less than 
one gram per liter, is observed at the end of reaction. Accordingly, the 
reaction mixture is typically filtered hot to remove this haze or resin. 
In general, after the reaction is deemed complete, for example, by NMR 
analysis, the reaction mixture is heated to decompose any residual 
initiator. For a di(ti-butyl) peroxide initiator, this temperature is 
typically about 160.degree. C. 
The isolated copolymer may then be reacted with a polyamine to form a 
polymeric succinimide. The preparation and characterization of such 
polysuccinimides and their treatment with other agents to give other 
dispersant compositions is described herein. 
A(4) Preferred Copolymers 
Preferred copolymers prepared by the present process include those where an 
unsaturated acidic reactant, most preferably maleic anhydride, is 
copolymerized with a "reactive" polyisobutene, in which at least about 50 
percent or more of the polyisobutene comprises the alkylvinylidene, more 
preferably, the methylvinylidene, isomer, to give a "polyPIBSA". 
Preferred are polyPIBSAs wherein the polyisobutyl group has an average 
molecular weight of about 500 to about 5000, more preferably from about 
950 to about 2500. Preferred are polyPIBSAs having an average degree of 
polymerization of about 1.1 to about 20, more preferably from about 1.5 to 
about 10. 
B. Polysuccinimides 
As noted above, polyamino polysuccinimides may be conveniently prepared by 
reacting a copolymer made by the present process with a polyamine. 
Polysuccinimides which may be prepared include monopolysuccinimides (where 
a polyamine component reacts with one succinic group), 
bis-polysuccinimides (where a polyamine component reacts with a succinic 
group from each of two copolymer molecules), higher succinimides (where a 
polyamine component reacts with a succinic group from each of more than 2 
copolymer molecules) or mixtures thereof. The polysuccinimide(s) produced 
may depend on the charge mole ratio of polyamine to succinic groups in the 
copolymer molecule and the particular polyamine used. Using a charge mole 
ratio of polyamine to succinic groups in copolymer of about 1.0, 
predominately monopolysuccinimide is obtained. Charge mole ratios of 
polyamine to succinic group in copolymer of about 1:2 may produce 
predominately bis-polysuccinimide. Higher polysuccinimides may be produced 
if there is branching in the polyamine so that it may react with a 
succinic group from each of greater than 2 copolymer molecules. 
The copolymers made by the present process, including preferred copolymers 
such as polyPIBSA, may be post-treated with a wide variety of other 
post-treating reagents. U.S. Pat. No. 4,234,435, the disclosure of which 
is incorporated herein by reference, discloses reacting succinic acylating 
agents with a variety of reagents to give post-treated carboxylic acid 
derivative compositions which are useful in lubricating oil compositions. 
C. Lubricating Oil Compositions 
The copolymers, polysuccinimides and modified polysuccinimides described 
herein are useful as detergent and dispersant additives when employed in 
lubricating oils. When employed in this manner, these additives are 
usually present in from 0.2 to 10 percent by weight to the total 
composition and preferably at about 0.5 to 8 percent by weight and more 
preferably at about 1 to about 6 percent by weight. The lubricating oil 
used with these additive compositions may be mineral oil or synthetic oils 
of lubricating viscosity and preferably suitable for use in the crankcase 
of an internal combustion engine. Crankcase lubricating oils ordinarily 
have a viscosity of about 1300 CSt 0.degree. F. to 22.7 CSt at 210.degree. 
F. (99.degree. C.). The lubricating oils may be derived from synthetic or 
natural sources. Mineral oil for use as the base oil in this invention 
includes paraffinic, naphthenic and other oils that are ordinarily used in 
lubricating oil compositions. Synthetic oils include both hydrocarbon 
synthetic oils and synthetic esters. Useful synthetic hydrocarbon oils 
include liquid polymers of alpha olefins having the proper viscosity. 
Especially useful are the hydrogenated liquid oligomers of C.sub.6 to 
C.sub.12 alpha olefins such as 1-decene trimer. Likewise, alkyl benzenes 
of proper viscosity, such as didodecyl benzene, can be used. 
Blends of hydrocarbon oils with synthetic oils are also useful. For 
example, blends of 10 to 25 weight percent hydrogenated 1-decene trimer 
with 75 to 90 weight percent 150 SUS (100.degree. F.) mineral oil gives an 
excellent lubricating oil base. 
Lubricating oil concentrates are also envisioned. These concentrates 
usually include from about 90 to 10 weight percent, preferably from about 
90 to about 50 weight percent, of an oil of lubricating viscosity and from 
about 10 to 90 weight percent, preferably from about 10 to about 50 weight 
percent, of an additive described herein. Typically, the concentrates 
contain sufficient diluent to make them easy to handle during shipping and 
storage. Suitable diluents for the concentrates include any inert diluent, 
preferably an oil of lubricating viscosity, so that the concentrate may be 
readily mixed with lubricating oils to prepare lubricating oil 
compositions. Suitable lubricating oils which can be used as diluents 
typically have viscosities in the range from about 35 to about 500 Saybolt 
Universal Seconds (SUS) at 100.degree. F. (38.degree. C.), although an oil 
of lubricating viscosity may be used. 
Other additives which may be present in the formulation include rust 
inhibitors, foam inhibitors, corrosion inhibitors, metal deactivators, 
pour point depressants, antioxidants, and a variety of other well-known 
additives. 
It is also contemplated that the additives described herein may be employed 
as dispersants and detergents in hydraulic fluids, marine crankcase 
lubricants and the like. When so employed, the additive is added at from 
about 0.1 to 10 percent by weight to the oil. Preferably, at from 0.5 to 8 
weight percent. 
D. Fuel Compositions 
When used in fuels, the proper concentration of the additive necessary in 
order to achieve the desired detergency is dependent upon a variety of 
factors including the type of fuel used, the presence of other detergents 
or dispersants or other additives, etc. Generally, however, the range of 
concentration of the additive in the base fuel is 10 to 10,000 weight 
parts per million, preferably from 30 to 5000 parts per million of the 
additive per part of base fuel. If other detergents are present, a lesser 
amount of the additive may be used. The additives described herein may be 
formulated as a fuel concentrate, using an inert stable oleophilic organic 
solvent boiling in the range of about 150.degree. to 400.degree. F. 
Preferably, an aliphatic or an aromatic hydrocarbon solvent is used, such 
a benzene, toluene, xylene or higher-boiling aromatics or aromatic 
thinners. Aliphatic alcohols of about 3 to 8 carbon atoms, such as 
isopropanol, isobutylcarbinol, n-butanol and the like, in combination with 
hydrocarbon solvents are also suitable for use with the fuel additive. In 
the fuel concentrate, the amount of the additive will be ordinarily at 
least 5 percent by weight and generally not exceed 70 percent by weight, 
preferably from 5 to 50 and more preferably from 10 to 25 weight percent. 
The following examples are offered to specifically illustrate this 
invention. These examples and illustrations are not to be construed in any 
way limiting the scope of this invention. 
EXAMPLES 
Example 1 (Comparative) 
Preparation of Polyisobutyl-24 PolyPIBSA 
To a 12-liter, 3-neck flask equipped with an overhead stirrer, thermometer, 
condenser, and heating mantle under nitrogen atmosphere was added 5,000 
grams (5.265 mole) of polyisobutene of about 950 molecular weight having 
the trade name ULTRAVIS-10 obtained from BP Chemicals wherein the 
methylvinylidene isomer comprised about 70% of the total composition, 
1547.1 grams (15.79 mole) maleic anhydride, and 2,500 ml chloroform. The 
mixture was heated to reflux, and to this was added 67.21 grams (0.41 
mole) 22'-azobis (2-methyl-propionitrite) ("AIBN"). The mixture was 
refluxed for two hours at which time an additional 67.21 grams of AIBN was 
added. This was followed by another two hours of reflux and a third charge 
(66.58 grams) of AIBN. A total of 201 grams (1.2 mole) of AIBN Was added. 
The reaction mixture was refluxed a total of 20 hours, and then allowed to 
cool. Two layers formed. The lower phase which contained mostly chloroform 
and unreacted maleic anhydride was discarded. The upper layer which 
contained mainly product and unreacted polyisobutene was separated. 
Solvent and maleic anhydride were removed in vacuo. A total of 4,360 grams 
of product having a saponification number of 40.4 was recovered. 
Example 2 (Comparative) 
Preparation of Polyisobutyl-24 PolyPIBSA 
To a 1-liter 3-neck flask equipped with a thermometer, overhead stirrer, 
nitrogen inlet and water condenser, was added 165.02 grams (0.174 mole) 
polyisobutylene (ULTRAVIS-10 from BP Chemicals) and 105 ml dichloroethane, 
then 16.4 grams (0.167 mole) maleic anhydride were added. The resulting 
mixture was heated to about 45.degree. C., and 3.3 grams (0.017 mole) 
tert-butylperbenzoate was added. The resulting mixture was heated to 
reflux (83.degree. C.). The reaction mixture was heated (with stirring) 
for a total of 30 hours. The reaction mixture was allowed to cool. The 
solvent was removed in vacuo. Unreacted maleic anhydride was removed by 
heating the residue to 150.degree. C. at 0.1 mm Hg vacuum. A total of 
176.0 grams product was obtained, which had an average molecular weight of 
about 5000. The conversion was about 60% . The saponification number was 
73.3. 
Examples 3 to 15 and Examples 1C to 5C (Comparative) 
Table I tabulates additional preparations following the basic synthetic 
procedure outlined in Examples 1 and 2. Table I lists the reactants, 
reaction temperature, time and solvent, and free radical initiator used. 
Example 12 was prepared using polyisobutene of about 1300 molecular weight 
having the trade name ULTRAVIS-30 obtained from BP chemicals wherein the 
methylvinylidene isomer comprised about 70% of the total composition. 
Comparison Examples 1C to 5C were prepared using a polyisobutylene of about 
950 molecular weight prepared with AlCl.sub.3 catalysis having the trade 
name Parapol 950 obtained from Exxon Chemical. 
TABLE I 
__________________________________________________________________________ 
Product 
of Maleic 
Example 
Polybutene 
Anhydride 
Solvent Initiator* 
Temp Time 
No. (g) (g) (ml) (g) .degree.C. 
Hrs. 
__________________________________________________________________________ 
2 Ultravis-10 
16.4 Dichloroethane 
TBPB 83 30 
(165.09) (105) (3.3) 
3 Ultravis-10 
119 Toluene AIBN 110 6 
(384.6) (250) (15.5) 
4 Ultravis-10 
32.3 Chlorobenzene 
DTBP 138 30 
(330) (210) (5.8) 
5 Ultravis-10 
1547 Dichloroethane 
AIBN 83 13 
(5000) (2500) (200) 
6 Ultravis-10 
119 Chloroform 
AIBN 74 24 
(384.6) (250) (15.5) 
7 Ultravis-10 
119 Methylene 
AIBN 40 94 
(384.6) Chloride (250) 
(15.5) 
8 Ultravis-10 
32.3 Toluene DTBP 110 30 
(330) (210) (5.8) 
9 Ultravis-10 
32.3 Xylene DTBP 144 39 
(330) (210) (5.8) 
10 Ultravis-10 
32.3 Xylene DTBP 114 4 
(330) (210) (5.8) 
11 Ultravis-10 
32.3 Toluene DTBP 110 4 
(330) (210) (5.8) 
12 Ultravis-30 
16.4 Dichloroethane 
TBPB 83-184 
26 
(217.1) (105) (3.3) 
13 Ultravis-10 
328.3 Chlorobenzene 
DTBP 138 28 
(3350) (1600) (42.6) 
14 Ultravis-10 
515.8 Chloroform 
TBPB 72 54 
(5000) (3000) (102.8) 
15 Ultravis-10 
1031 Chloroform 
TBPB 72 48 
(10,000) (6000) (205.6) 
then 140 
2 
1C Parapol 950 
119 Toluene AIBN 110 6 
(384.6) (250) (15.5) 
2C Parapol 950 
23.8 Dichloroethane 
AIBN 83 4 
(76.4) (50) (2.33) 
3C Parapol 950 
32.3 Toluene DTBP 110 30 
(330) (210) (5.8) 
4C Parapol 950 
32.3 Xylene DTBP 114 30 
(330) (210) (5.8) 
5C Parapol 950 
32.3 Chlorobenzene 
DTBP 138 30 
(330) (210) (5.8) 
__________________________________________________________________________ 
*AIBN = 2,2azobis (2methyl-propionitrite); DTBP = ditertbutyl peroxide; 
TBPB = tertbutyl peroxybenzoate 
**Molecular weight 1300 
EXAMPLE 16 
A 500-ml, 3-necked flask was charged with 100 g of a polyPIBSA/polybutene 
mixture (prepared according to the method of Example 5) which comprised 
about 38 weight percent polyPIBSA and about 62 weight percent (0.0653 mol) 
unreacted polyisobutene (of which about 68 weight percent (0.0444 mol) 
comprised the methylvinylidene isomer). The mixture was heated to 
70.degree. C. Then, 8 g (0.0816 mol) maleic anhydride and 1.7 g (0.0116 
mol) di-tert-butyl peroxide were added to the mixture. The mixture was 
stirred and heated to 150.degree. C. for 5 hours. After allowing the 
mixture to cool, 150 ml hexane was added to precipitate unreacted maleic 
anhydride which was then removed by filtration. The hexane was removed by 
stripping for 4 hours at 36 mm Hg (abs) at 90.degree. C. The filtered 
product had an unreacted maleic anhydride content of 0.08 weight percent, 
as determined by gas chromatography. The saponification number of the 
final product was determined to be 84 mg KOH/g sample. The amount of 
unreacted polybutene was determined to be 28.2% by column chromatography. 
Example 17A 
A 22-liter, 3-necked flask was charged with 3752 g (3.95 mol) of 
polyisobutene (BP Ultravis 10) and 2800 g of a polyPIBSA/polyisobutene 
mixture (prepared according to Example 13) which comprised about 57 weight 
percent polyPIBSA and about 43 weight percent (1.27 mol) unreacted 
polyisobutene. The mixture was heated to 91.degree. C.; then 14 g (0.143 
mol) maleic anhydride and 2.7 g (0.0185 mol) di-tert-butyl peroxide (DTBP) 
were added. A slight exotherm was noticed where the temperature increased 
to 147.degree. C. The mixture was stirred and heated at 140.degree. C. for 
one hour. After standing at room temperature overnight, the mixture was 
heated to 140.degree. C. and 378 g (3.86 mol) maleic anhydride and 56.7 g 
(0.388 mol) of DTBP were added. The mixture was stirred and heated at 
140.degree. C. for 6.5 hours. The mixture was allowed to cool to ambient 
temperature overnight. The mixture was heated to 80.degree. C. and vacuum 
was applied at 28 inches Hg (vac); the temperature was increased to 
200.degree. C. The mixture was stripped at 200.degree. C. and 28 inches Hg 
(vac) for 2 hours to remove any unreacted maleic anhydride. Analysis of 
the final product by proton NMR showed that a significant amount of the 
polybutene methylvinylidene isomer had disappeared along with the maleic 
anhydride. 
Example 17B 
A 22-liter, 3-necked flask was charged with 8040 g (8.46 mol) polyisobutene 
(BP Ultravis 10) and 6000 g of a polyPIBSA/polybutene mixture prepared 
according to Example 17A. The mixture was heated to 109.degree. C., then 
840 g (8.57 mol) maleic anhydride and 126 g (0.863 mol) DTBP were added. 
The resulting mixture was stirred and heated at 140.degree. C. for 5.25 
hours. The mixture was cooled to ambient temperature. The mixture was then 
heated to 128.degree. C. with stirring and an additional 153 g (1.561 mol) 
maleic anhydride and 23 g (0.158 mol) DTBP were added. The mixture was 
stirred and heated at 140.degree. C. for 3.5 hours and then an additional 
153 g (1.561 mol) maleic anhydride and 11.8 g (0.0808 mol) DTBP were 
added. The mixture was stirred and heated at 140.degree. C. for an 
additional 3.67 hours. The mixture was cooled to ambient temperature. The 
mixture was then stirred and heated at 186.degree. C. for one hour while 
vacuum was applied to strip the unreacted maleic anhydride from the 
product. The product had a saponification number of 85.8 mg KOH/g. 
Inspection of the proton NMR spectrum of the final product indicated that 
the polybutene methyl vinylidene isomer was significantly depleted and 
that the maleic anhydride was totally consumed. 
Example 18 
Preparation of PolyPIBSA TETA Polysuccinimide with a Low Degree of 
Polymerization 
To a 5-liter flask equipped with a heating mantle, overhead stirrer and 
Dean Stark trap under nitrogen sweep, was added 1000 g polyPIBSA prepared 
according to Example 17B (saponification number 85.8, molecular weight 
about 2500) and 999 g Chevron 100NR diluent oil. The mixture was heated to 
60.degree. C.; then 75.78 g triethylene tetraamine (TETA) was added. The 
mixture was heated to 160.degree. C. and kept at temperature for 4 hours. 
A total of 7.0 ml water was recovered from the Dean Stark trap The 
reaction mixture was then maintained at 160.degree. C. under vacuum for 2 
hours. The reaction mixture was allowed to cool. Obtained was 2018.2 g of 
product having % N=1.35. 
Example 19 
Preparation of PolyPIBSA HPA Polysuccinimide With a Low Degree of 
Polymerization 
To a 5-liter flask equipped with a heating mantle, overhead stirrer and 
Dean Stark trap (under nitrogen sweep) was added 1000 g polyPIBSA prepared 
according to Example 17B (saponification number 85.8 molecular weight 
2500) and 932 Chevron 100NR diluent oil. The mixture was heated to 
60.degree. C.; to this was added 142.45 g heavy polyamine ("HPA") No. X 
obtained from Union Carbide Corporation. The mixture became very thick. 
The reaction mixture was heated to 165.degree. C. and maintained at that 
temperature for 4 hours; the mixture became less viscous. Then the 
reaction mixture was heated at 165.degree. C. under vacuum for 2 hours. 
The mixture was allowed to cool. Obtained was the above-identified product 
having % N=2.23. 
Example 20 (Comparative) 
An experiment was performed in a manner similar to Examples 17A and 17B, 
but in the absence of any added oligomeric copolymer solvent. The 
resulting mixture, upon heating, formed a significant amount of maleic 
anhydride (MA) resin, as indicated by total disappearance of the MA peak 
in the proton NMR, while still leaving a large amount of methyl vinylidene 
protons. Moreover, MA resin formation was evidenced by the product being 
stuck to the reactor walls and the formation of tar. 
Example 21 
Proton NMR Analysis of Reaction of Polyisobutene with MA 
The reaction of PIB with MA can be monitored by proton NMR. The MA peak in 
deuterochloroform is located at 7.07 ppm and the methyl vinylidene olefin 
hydrogens are at 4.61 and 4.87 ppm. Disappearance of these peaks, 
especially the PIB vinylidene peaks, indicates copolymerization with the 
MA. IR can also be used to confirm that copolymerization is occurring. 
Generally, the reaction is run until the MA olefin peak disappears and the 
methyl vinylidene peaks have significantly decreased. 
Example 22 
Saponification Number of PIBSA and PolyPIBSA 
Approximately one gram of sample is weighed and dissolved in 30 ml xylene 
in a 250-ml Erlenmeyer flask at room temperature. Unless otherwise noted, 
the polyPIBSA product samples were filtered at about reaction temperature 
to remove any MA hydrolysis product (i.e., fumaric acid) and any poly MA 
resin. 
Twenty-five ml of KOH/methanol is added to the xylene solution. A reflux 
condenser is attached and the mixture is heated to reflux using a 
hotplate/stirrer and held at reflux for 20 minutes. A ceramic spacer is 
placed beneath the flask, and 30 ml of isopropyl alcohol is added through 
the condenser. The sample is then cooled to about room temperature and 
back titrated with 0.5 Normal HCl, using a Metrohm 670 auto titrator and a 
Dosimat 665 pump system. 
Comparisons with blanks provide the saponification number (SAP number), 
which is mg of KOH/gm of sample. 
Examples 23-25 
Examples 23-25 were carried out following the general procedure of Examples 
16, 17A and 17B. The results are shown in Table II. 
In Example 24, proton NMR showed a significant consumption of polyisobutene 
methyl vinylidene isomer and maleic anhydride. In Example 25, the maleic 
anhydride and free radical initiator were added by slugs. 
Example 26 
A reaction mixture containing 350 grams of a 45 weight percent polyPlBSA 
and 55 weight percent unreacted polyisobutene mixture having a SAP Number 
of 34 was combined with 150 grams BP ULTRAVIS 30, a high vinylidene 
polyisobutene having an average molecular weight of about 1300 and 176 
grams of a Chevron 100 neutral lubricating oil. The mixture was heated to 
50.degree. C. Twenty-two (22) grams of maleic anhydride and 5 grams of 
t-butylperoxy-2-ethyl hexanoate (t-butyl peroctoate) were added. The 
reaction temperature was raised to 90.degree. C. and held at this 
temperature for 4 hours. A product with a SAP Number of 26 was produced. 
Proton NMR indicated a very slow reaction rate. 
Example 27 
A reaction mixture containing 500 grams of a 45 weight percent polyPIBSA 
and 55 weight percent unreacted polyisobutene mixture having a SAP Number 
of 34 was combined with 214 grams BP ULTRAVIS 30, a high vinylidene 
polyisobutene having an average molecular weight of about 1300. The 
mixture was heated to 110.degree. C. and 31.4 grams of maleic anhydride 
was added. Every 15 minutes starting from the MA addition time, 6.53 grams 
of 100 neutral oil and 0.73 grams of t-butylperoxy-2-ethyl hexanoate 
(t-butyl peroctoate) were added. Additions were continued for the first 2 
hours and 30 minutes. Thereafter the reaction was held at 110.degree. C. 
for 5.5 hours. This produced a product which had a SAP Number of 31. 
Proton NMR showed a slow reaction rate. 
Example 28 
A reaction mixture containing 464 grams of a 45 weight percent polyPIBSA 
and 55 weight percent unreacted polyisobutene mixture having a SAP Number 
of 34 was combined with 316 grams BP ULTRAVIS 30, a high vinylidene 
polyisobutene having an average molecular weight of about 1300. The 
mixture was heated to 120.degree. C. and 31.2 grams of maleic anhydride 
and 5.85 grams of t-butylperoxy-2-ethyl hexanoate (t-butyl peroctoate) 
were added. The reaction temperature was raised to and held at 120.degree. 
C. for 6 hours. A product with a SAP Number of 33 was produced. 
Example 29 
A reaction mixture containing 259 grams of a 45 weight percent polyPIBSA 
and 55 weight percent unreacted polyisobutene mixture having a SAP number 
of 34 was combined with 177 grams BP ULTRAVIS 30, a high vinylidene 
polyisobutene having an average molecular weight of about 1300. The 
mixture was heated to 130.degree. C. and 12.6 grams of maleic anhydride 
and 3.32 grams of di-t-butylperoxide were added. The reaction temperature 
was held at 130.degree. C. for 5 hours. Then 5.1 grams of maleic anhydride 
and 0.7 grams of di-t-butylperoxide were added. The temperature was raised 
to 140.degree. C. and then held these for 4.5 hours. The product had a SAP 
Number of 41. Proton NMR showed a significant reduction in polyisobutene 
methyl vinylidene isomer. 
Example 30 
A reaction mixture containing 896 grams of polyPIBSA containing some 
unreacted polybutene was combined with 1883 grams BP ULTRAVIS 30. The 
mixture was heated to 140.degree. C. and 142 grams of maleic anhydride and 
21.2 grams of di-t-butylperoxide were added. The reaction temperature was 
raised and held at 140.degree. C. for 4 hours and then heated to 
200.degree. C. for 2 hours. The product had a SAP Number of 49. 
Example 31 (Comparative) 
A reactor containing 721 grams BP ULTRAVIS 30 was heated to 140.degree. C. 
and 38.8 grams of maleic anhydride and 8.2 grams of di-t-butylperoxide 
were added. This reaction was done in the absence of added polyPIBSA 
solvent. The reaction temperature was held at 140.degree. C. for 7 hours. 
An abundance of tarry resin, believed to be derived from the maleic 
anhydride was evident. The mixture was filtered hot. The product had a SAP 
number of 17 after the resin was filtered out. The percent actives was 37% 
. 
Example 32 
This reaction shows that after the copolymer is formed, unreacted PIB can 
be reacted with maleic anhydride to form thermal PIBSA. 
PolyPIBSA prepared in a manner similar to Example 17B having a SAP Number 
of 86 was charged to a reactor and heated to 204.degree. C. A molar 
equivalent of MA (43.3 g), relative to unreacted non-vinylidene 
polybutene, of MA was added and the mixture heated to 232.degree. C. and 
held at this temperature for 4 hours. The temperature was reduced to 
210.degree. C. and the pressure was reduced to 28 inches of mercury. The 
reduced pressure and temperature was maintained for one hour. Then the 
mixture was filtered. The product had a SAP Number of 88. The results of 
Examples 26-32 are shown in Table II. 
TABLE II 
__________________________________________________________________________ 
Wt % PIB 
PIB 
PIB 
MA Init. 
PIB PolyPIBSA 
in Rx Rx Temp 
Rx time 
SAP Wt % 
Example 
MW Mole 
Mole 
Initiator Type 
Mole 
Grams 
Grams Mixture 
.degree.C. 
Minutes 
Number 
Actives 
__________________________________________________________________________ 
23 950 
0.00 
0.08 
Di-t-Butyl Peroxide 
0.12 
0.0 
100 0.0 150 300 90 71.8 
24 950 
3.95 
4.00 
Di-t-Butyl Peroxide 
0.40 
3752.0 
2800.0 
57.3 140 400 -- -- 
25 950 
8.46 
8.57 
Di-t-Butyl Peroxide 
0.86 
8040.0 
6000.0 
53.5 140 620 76 77.2 
.sup. 26.sup.a 
1300 
0.12 
0.23 
t-Butyl Peroctoate 
0.02 
150.0 
350.0 22.2 90 240 26 -- 
.sup. 27.sup.b 
1300 
0.17 
0.32 
t-Butyl Peroctoate 
0.03 
214.5 
500.0 27.5 110 330 31 -- 
28 1300 
0.24 
0.32 
Di-t-Butyl Peroxide 
0.04 
315.8 
463.8 40.5 120 240 33 -- 
29 1300 
0.14 
0.13 
Di-t-Butyl Peroxide 
0.03 
176.9 
259.0 40.6 130 450 41 -- 
30 1300 
1.45 
1.45 
Di-t-Butyl Peroxide 
0.15 
1883.0 
896.0 70.3 140 240 49 60.4 
31 1300 
0.55 
0.40 
Di-t-Butyl Peroxide 
0.06 
721.0 
0.0 100.0 140 420 17 32.6 
32 950 
0.00 
0.44 
None 0.00 
0.0 
700.0 0.0 232 240 88 78.0 
__________________________________________________________________________ 
.sup.a The reaction mixture contained 176 grams of neutral lubrication oi 
(26 wt. % in reaction mixture). 
.sup.b The reaction mixture contained 65.25 grams of neutral lubrication 
oil (8.4 wt. % in reaction mixture).