CA2119010A1 - One-step process for the preparation of alkenyl succinic anhydride - Google Patents

Abstract

A process for the preparation of an alkenyl-substituted succinic anhydride wherein the alkenyl substituent has a number average molecular weight of from about 500 to 5000 and the average number of succinic groups per alkenyl group is greater than 1.2 which comprises reacting a polyolefin having an alkylvinylidene isomer content of less than about 10 percent and a number average molecular weight of about 500 to 5000 with maleic anhydride in the presence of a free radical initiator at a temperature in the range of about 80 ·C to 200 ·C for a period of less than 20 hours, wherein the molar ratio of maleic anhydride to polyolefin is about 1.0:1 to 9:1, and wherein the half-life of the decomposition of the free radical initiator is about 5 minutes to 10 hours at the reaction temperature.

Description

2 1 1 9 0 1 0 PCl/VS93/0690~ ~

~`ONE:-8T15~ ~?ROCBS~ FOI~ E PRI~:PA}U~q!ION OF
02AI~XE~ 1 CINIC AN~YDRIDE
03 : ~`
04BACXGROUND OF T.~E INVENTION

06 The present invention relates to a process for preparing 07 compo~itions which are useful as intermediates for ::~
08 di~per ants used in lubricating oil compositions or as 09 dispersants themselves~ In addition, some of the ~ ~:
compositions prepared by the presant process are useful in 1~ the preparation of high molecular weight dispersants which 12 have ~up~rior dispersant properties for dispersing sludge 13 and varnish. Such high molecular weight dispersants also .
1~ advantageously impart fluidity ~odifying properties to ~:
lubricating oil compositions which are sufficient to allow 16 ~ elimination of 50m~ proportion of vi~cosity index improver 17 from multigrade lubricating oil compositions which contain 1~ these di~persants.
~g It is kn~wn in the art that alkenyl-~ubstituted succinic 2~ anhydrides have b ~n used as dispersants. Such 22 alkenyl-substituted succinic anhydride~ have been prepared 23 by two different processes, a thermal process ~seet e.g., 24 U~S. Pat~nt No. 3~361,673) and a chlorination process (see, e.g., U.S~ Patent No. 3,172,892). The polyisobutenyl 26 succinic anhydride ("PIBSA"~ produced by the thermal process 27 has been characterized as a monomer containing a double bond 28 in the product. Although the exact structure of 29 chlorinaiion PIBSA has not ~een definitively determined, the chlorination process PIBSA materials have been characterized 31 as monomers containing either a double bond, a ring other 32 than succinic anhydride ring and/or chlorine in the product.
33 [(See J. Weill and B. Sillion, "Reaction of Chlorinated :~

3~ Polyisobutene with Maleic Anhydride: Mechanism Catalysis by .

W094/02523 PCT/US93/069~C

2~g~

01 Dichloramaleic Anhydride", Revue de 1'Institut Francais du 02 Petrole, Vol. 40, No. 1, pp. 77-89 (January-February, 03 1985).] Such compositions include one-to-one monomeric ~- adducts (see, e.g., U.S. Patents Nos. 3,219,666; 3,381,022) 05 as well as adduct~ having polyalkenyl-derived sub6tituents 06 adducted with at least 1.3 succinic groups per 07 polyalkenyl-derived substituent (see, e.g., U.S. Patent 08 No. 4,234,435). ~ `
og ', 10 Commonly assigned International Patent Application ;~
11 No. PCTtUS89/04270, Publication No. WO 90/03359, dated 12 April 5, 1990 and entitled "Novel Polymeric Dispersants 13 Having Alternating Polyalkylene and Succinic Groups"
1~ discloses copolymers prepared by reacting an unsaturated acidic reactant, such as maleic anhydride, with a high lC - molecular weight olefin, such as polyisobutene, in the 17 presence of a free radical initiator, wherein at least about ;~
18 20 percent of the total high molecular weight olefin ~9 comprises an alkylvinylidene isomer and wherein the high molecular weight olefin has a sufficient number of carbon 21 atoms such that the resulting copolymer is soluble in 22 lubricating oil.

2~ U.S. Patent No. 4,234,435 to Meinhardt et al., assiqned to 25 The Lubrizol Corporation, discloses substituted succinic ; --~
26 acylating agents derived fr~m polyalkenes, such as 27 polybutene, and a dibasic carboxylic reactant, such as 28 maleic acid or anhydride, wherein the polyalkenes have a 2~ number average molecular weight of about 1300 to 5000 and a ratio of weight average to number average molecular weight 31 of about 1.5 to 4. These acylating agents are further 32 characterized by the presence of an average of at least 33 1.3 succinic groups for each equivalent weight of 3~ substituent group. Meinhardt et al. teach that such WQ94/02523 2 1 1 9 0 1 0 PCT/US93/0690~ ;

ol acylating agents are prepared by heating the polyalkene and ~ ~
02 carboxylic reactant with chlorine in a one-step proce~s or, ~ ~-03 alternatively, by first reacting the polyalkene with ~-~ chlorine and then reacting the resulting chlorinated OS poly~lkene with the carboxylic reactant. This patent 06 further teache~ that such substituted succinic acylating 07 agent~ ~nd thQir derivatives are u~eful lubricating oil 08 di~per~ant additives which also exhibit vis~osity index 09 improving properties.
,, ~, 11 U.S. Patent No. 4,873,004 to Beverwijk et al., assigned to 12 Shell Oil Company, discloses an alkyl or alkenyl-substitut~d ~
13 ~uccinic anhydride, wherein the alkyl or alkenyl group on ~-1~ the anhydride has a number average molecular weight of from lS 600 to 1300 and wherein the average number of succinic 16- group~ per alkyl or alkenyl group is between 1.4 and 4~0. ;~
17 Beverwijk et al. teach that these alkyl or 18 alkenyl-substituted suc~inic anhydrides can be prepared by ~ -19 mixing a polyolefin with maleic anhydride and passinq chlorine through ~he mixture, or by reacting a chlorinated 21 polyolefin with maleic anhydride. Beverwijk et. al. further ~-22 teach that the ~uccinimide derivatives of such substituted 23 succinic anhydrides are useful dispersant additives for 24 lubricating oils.

26 U.S. Patent No. 3,367,864 to Elliot et al., assigned to 27 Castrol Limited, discloses in Example I thereof the 28 preparation of a polyisobutenyl succinic anhydride by the 29 reaction of about a 1:1 molar ratio of polyisobutylene and maleic anhydride in refluxing toluene and in the presence of 31 a di-tertiary-butyl peroxide free radical initiator. Elliot ;~
32 et al. further teach that the succinic anhydride product -~;
33 produced by this method is similar to the product obtained 0~ by thermally reacting polyisobutylene and maleic anhydride 02 at 240C for 30 hours.

~ It has generally been recognized in the art that th~
05 polyisobutenyl succinic anhydride prepared by ~mploying a 06 conventional thermal process is primarily a mono~eri.c 07 one-to-one adduct, that is, having about one succinic group 08 per polyisobutenyl group in the product. However, recent 09 analysis of a number of polyisobutenyl succinic anhydride products produced by following the free radical-initiated 11 process of Example I of U.S. Patent No. 3,367,864 has -12 resulted in a finding that ~uch products are monomeric 13 adduct~ containing an average of about 1.6 or greater 14 succinic groups per polyiso~utenyl group.
16 ~ Moreover, European Patent Application Publication 17 No. 0,355,89s A2, publi~hed February 28, 1990, disc~oses a 18 process for khe preparation of polyolefin-substituted 19 succinic anhydrides in which the average molar ratio of succinic groups to polyolefin chain~ is greater than 1.3 21 to ~, which comprises heating a polyolefin with at least a 22 molar excess of maleic anhydride, wherein the polyolefin 23 employed con~ains at least 70 percent of the terminal 2~ groupings in a structure havinq an alpha olefinic bond or structures in equilibrium with such alpha olefinic 26 structures. Thus, this European patent application teaches 27 that greater than 1.3 succinic groups per polyolefin group 28 can be obtained when the polyolefin employed is one wherein 29 the predominant isomer is an alkylvinylidene.
3~ SUMMARY OF THE INVENTION

33 The present invention is directed to a one-step process for 3~ the preparation of an alkenyl-substituted succinic anhydride ~094/02523 PCT/~S93/~690~
2 I i r~ ~)1 0 : ~

01 wherein the alkenyl substituent has a number a~erage 02 molecular weight of from about 500 t~ 5000 and the average -03 number of succinic groups per alkenyl group is greater than ~ 1.2 which compri~e~ reacting a polyolefin having an 05 alkylvinylidene isomer content of les~ than about 10 percent 06 and a number average molecular weight of about 500 to 5000 07 with maleic anhydride in the presence of a free radical 08 in~tiator at a temperature in the range of about 80C to 09 220C for a period of less than ~0 hours, wherein the molar ratio of maleic a~hydride to polyolefin is ab~ut 1.0:1 to 1~ 9:1, and wherein the half-life of the decomposition of the 12 free radîcal initiator ic about 5 minutes to 10 hours at the :
~3 reaction temperature.

~5 Among other factors, the present invention is based on the 16 ~ discovery that certain alkenyl-substituted succinic ~ ~
17 anhydrides containing an average of greater than ~ ~ -~8 1.2 ~uccinic groups per alkenyl group can be effectively 19 prepared in high yields and conversions at shorter reaction .
times by employing a unique cne-step process which does not 21 in~olve the use of chlorine, thereby resulting in a product 22 having improved environmental properties.
23 ~:~
2~ The average nu~ber of succinic groups per alkenyl group in the alkenyl succinic anhydride produced by the present 26 process is greater than 1.2, preferably greater than 1.3, 27 more preferably greater than 1.3 to about 4.0, and most 28 preferably greater than 1.3 to about 2.5.

Suitable polyolefins for use in preparing the alkenyl 31 succinic anhydride products will have a number average 32 molecular weight of about 500 to 5000, preferably from about 33 700 to 3000, and more preferably, from about 900 to 2500.
3~ Generally, such polyolefins will contain at least about -W094/02523 PCT/US93/0~90'-9~

01 35 carbon atoms, preferably about 50 carbon atoms or 02 greater. Preferred polyolefins are polybutene and 03 polypropylene, particularly polyisobutene. Suitable 04 polyolefins will also contain an alkylvinylidene isomer 05 content of less than about 10 percent.

07 The succinic anhydride products prepared by the process of 08 the invention are useful as dispersants themselves and also 09 as intermediates in the preparation of other dispersant ::
additives having improved dispersancy and/or detergency 1~ properties when employed in a lubricating oil.

13 The products produced by the instant process can also be . ~:
1~ used to form polysuccinimides which are prepared by reacting ~5 the alkenyl succinic anhydride with a polyamine to give a 16 'polysuccinimide. These polysuccinimides are useful as 17 disper~ants andlor detergents in fuels and oils. In 18 addition, these polysuccinimides have advantageous viscosity -19 modifying properties, and may provide a viscosity index credit (~VDI~ Credit") when used in lubricating oils, which 21 may permit elimination of some portion of viscosity index 22 improver ("V.I. Improvert') from multigrade lubricating oils 23 containing the same.
2~
Moreover, the succinic anhydrides prepared by the present 26 process can be employed to make modified polysuccinimides 27 wherein one or more of ~he nitrogens of the polyamine 28 component is substituted with a hydrocarbyl oxycarbonyl, a 29 hydroxyhydrocarbyl oxycarbonyl or a hydroxy 3~ poly(oxyalkylene)-oxycarbonyl. These modified -:
31 polysuccinimides are improved dispersants and/or detergents 32 for use in fuels or oils.

3~

"'~ 94/02523 P ~ /US93tO690~
21i91~ 1 0 01 Accordingly, the alkenyl cuccinic anhydrides made by the 02 pre~ent process are useful in providing a lubrîcating oil 03 compo~ition comprising a major amount of an oil of ~ -04 lubricating viscosity and an amount of a succinic anhydride, 05 poly~uccinimide or modified succinimide additive sufficient 06 to provide dispersancy and/or detergency. The~e additiveç
07 may ~l~o be formulated in lubricating oil concentrates which 08 contain about 10 to about 50 weight percent of the additive.

Furthermore, the alkenyl succinic anhydrides formed by the 11 present process can be used to provide a fuel composition 12 comprising a major portion of a fuel boiling in a gasoline ~
13 or diesel range and an amount of succinic anhydride, -14 polysuccinimide or modified succinimide additive sufficient ~5 to provide di~p~rsancy and/or detergency. These additives 16 ' can also be used to make fuel concentrates compri~ing an 17 inert stable ol~ophilic organic solvent boiling in the range 18 of about ~50F to about 400F and from about 5 to about lg 50 weight percent of such additive.

23 The high molecular weight polyolefins u~ed in the 2~ prepsration of the instant alkenyl succinic anhydrides are of sufficiently long chain length so that the resulting 26 composition is soluble in and compatible with mineral oils, 27 fuels and the like. Thus, the polyolefin will typically 28 contain about 35 carbon atoms or greater, preferably about 29 50 carbon atoms or greater.
31 Such high molecular weight polyolefins are generally 32 mixtures of molecules having dif f erent molecular weights and 33 can have at least one branch per 6 carbon atoms along the 3~ chain, preferably at least one branch per 4 carbon atoms W094/02s23 PCT/US93/069~-90~

01 along the chain, and move preferably about one branch per 02 2 carbon atoms along the chain. TheQe branched chain 03 olefins may conveniently comprise polyalkenes prepared by 0~ the polymerization of olefins of from 3 to 6 carbon atoms, 05 and preferably from olefins of from 3 to 4 carbon atoms, and OC more preferably from propylene or isobutylene. The 07 addition-polymerizable olefins employed are normally 08 l-olefin~. The branch may be of from 1 to 4 carbon atoms, 09 more usually of from 1 to 2 carbon atoms and preferably ~0 methyl.
Il ~ --~
12 The polyolef ins employed in the process of the present -13 invention may be prepared by conventional techniques well 1~ known in the art, such as aluminum chloride-catalyzed lS polymerization of lower olefins.

17 Preferred polyolefins are polyisobutenes having number ~8 average molecular weights of about 500 to about 5000, more ~9 preferably about 700 to about 3000. Especially preferred are those polyisobutenss having number average molecular 21 weigh~s of about 900 to 2500.

23 The p~lyolefins employed in the instant process will also 2~ have a low alkylvinylidene isomer content, that is; less than abou~ 10 percent alkylvinylidene. As used herein, the 26 term "alkylvinylidene" or "alkylvinylidene isomer" is meant 27 to indicate olefins having the formula:

2~ Rl 31 R2--C = CH2 3 wherein Rl is lower alkyl of 1 to about 6 carbon atoms and 3~ R2 is a polyolefin residue. Consequently, high -~94/02523 PCT/US93/0690~ .:
21~ n 1~1 d ; `
~`

g ,.. .
...
`

01 alkylvinylidene polyolefins having greater than about a ~ ~
02 10 percent alkylvinylidene content, such a~ the commercially ~ ::
03 available Ultravis type of polyisobutene, are unsuitable for ~ use in the process of the present invention, since such 05 ~aterials tend to form copolymers with maleic anhydride in ~ ~
OC the presence of a free radical initiator. ~::
07 ~ :
08 In general, the ratio of weight average molecular weight 09 (Mw) to number average molecular weight (MN), that is, MW/MN, for the polyolefins employed in the present 11 invention will fall within the range of about 1.1 to 4Ø ~-12 The MW and ~N values for the polyolefins used in this 13 invention are determined by gel permeation chromatography 1~ (GPC) as described, for example, in U.S. Patent No. 4,234,435 to Meinhardt et al.
16 ~-1 A~ noted above, the present invention relates to a unique ~8 one-step process for preparing an alkenyl succinic anhydride -19 having greater than 1.2 succinic groups per alkenyl group, which involves reacting a polyolefin with maleic anhydride 21 in the presence of a free radical initiator to give an 22 alkçnyl succinic anhydride having an average of greater than 23 1.2 succinic groups per alkenyl group.
2~
Accordi~gly, in the process of the instant invention, the polyolefin and maleic anhydride are heated in the presence 27 of a free radical initiator to a temperature in the range of 28 about 80C to about 220C, preferably about 120C to about 29 180C, more preferably about 140C to about 180~C, and most 3 preferably, about 1~5C to about 16C. The time of reaction will vary, depending in part upon the reaction 2 temperature, but will generally be less than 20 hours, 3 preferably about 1 to 15 hours. The reaction pressure can 3~
' ~' W~94/02523 PCT/US93/069~-~
9~

01 be atmospheric, although higher pressures up to about 02 50 p8ig are preferred~ The molar ratio of maleic anhydride 03 to polyolefin will generally be about 1.0:1 to about 9:1, 0~ preferably about 1.5:1 to about 5:1, and more preferably 05 about 2:1 to about 4:1. Upon completion, this reaction will 06 preferably result in greater than about a 50 percent 07 conversion of polyolefin to alkenyl succinic anhydride.

09 The reaction involved in the present process can be carried out in the presence or absence of a solvent which is inert 1 to the reaction taking pl~ce. When employed, suitable 12 solvents include toluene, xylene, C9 aromatics, neutral oil, 13 and the like. Preferably, the reaction is carried out 1~ without a solvent.
15 , 1~ The alkenyl succinic anhy~ride produced by the present 17 process will contain an average of greater than about .
~8 1.2 succinic groups per alkenyl group, preferably greater ~9 than 1.3, more preferably greater than 1.3 to about 4.0, and 20 most prefera~ly greater than 1~3 to about 2.5 succinic .
21 groups per alkenyl group. ~:

23 In general, the process of the present invention can be :~
2~ initiated by any free radical initiator. Such initiators are well known in the art. However, the choice of free 26 radical initiator may be influenced by the reaction 27 temperature employed.

29 It has now been found that if the half-life of the decomposition of the free radical initiator at the 31 temperature of reaction is in the range of about 5 minutes 32 to 10 hours, preferably about 10 minutes to 5 hours, and :

33 more preferably about 10 minutes to 2 hours, then the W094/02523 PCT/US93/~90~ ~
211.'~0 ~

-11- `, 01 desired alkenyl succinic anhydride product can be 02 effectively prepared in high yields and conversions at short 03 react~on times.
0~ :
05 The preferred free-radical initiators ~re the peroxide-type ~ initiators and azo-type initiators.

03 Th~ peroxide-type free-radical initiator can be organic or 09 inorganic, the organic having the general formula: R300R3' 10 wh~re R3 is any organic radical and R3' i8 selected from the ;~
1~ group consisting of hydrogen and any organic radical. Both 12 R3 and ~' can be organic radicals, preferably hydrocarbon, 13 aroyl, and acyl radicals, carrying, if desired, substituents 1~ such as hal~gens, etc. Preferred peroxides include di-tert-b~tyl peroxide, tert-butyl peroxybenzoate, and 16 dicuoyl peroxide.
17 ~ -~8 Examples of other suitable peroxides, which in no way are 19 limiting, include benzoyl peroxide; lauroyl peroxide; other ~-terti~ry butyl peroxides; 2,4-dichlorobenzoyl peroxide;
2~ tertiary butyl hydroperoxide; cumene hydroperoxide; diacetyl 22 per4xide; acetyl hydroperoxide; diethylperoxycarbonate;
23 tertiary butyl perbenzoate; and the like.

The azo-type compounds, typified by alpha, 2C alpha'-azo-bisisobutyronitrile (AIBN), are also well-known 27 free-radical promoting materials. These azo compounds can 28 be defined as those having present in the molecule the group 29 -N=N wherein the balances are satisfied by organic radicals, 3~ at least one of which is preferably attached to a tertiary 31 carbon. Other suitable azo compounds include, but are not 32 limited to, p-bromobenzenediazonium fluoborate;
33 p-tolyldiazoamino-benzene; p-bromobenzenediazonium 3~

W094/02523 PCT/US93/069~

9~ ~

01 hydroxide; azomethane and phenyldiazonium halide6. A
02 suitable list of azo-type compounds can be found in U.S.
03 Patent No. 2,551,813, issued May 8, 1951 to Paul Pinkney.
0~
05 The half-life values for known free radical initiators at 06 various temperatures are readily available from the 07 literature. See, for example, C. Walling, ~Free Radicals in `~
08 Solution~, John Wiley and Sons, Inc., New York (1957).
09 Alternatively, the half-life values are available from the ~-various suppliers of free radical initiators, such as Witco, 11 Atochem, Lucidol, Phillips Petroleum, and the like. ~Table 1 -~
12 lists the half-life temperatures for a number of free 13 radical initiators at a given half-life. The half-life 1~ temperature is the temperature required for a free radical initiator to exhibit a specified half-life. As a rule, the 16 - higher the half-life temperature, the lower the half-life of 17 the free radical initiator. --~8 -~
19 ~:

2~

2~
~ -27 ~-~

;-3~
- ~ .
.,:..

~U? 94/02523 PCT/US93/0690~

2 1 1~0~ 1 0 3 TAl~ 1 _ 0~ I~ LIFJ~ 1PERA~UR~5 OF VARIOU~ F~ RADICAL
05 INITIA~ ORS A~ SPEClFI~CD ~ ;
0~ Balf-~if- ~r~p-r~tur-, C.
-- _, , ~

08 In~tl-tor ~. ~iD. _ ~r-. 10 09 Dialkyl P~roxid~: . . .
di-t-butyl perox$de 173 166 143 135 _ 129 11 d~-t-amyl peroxide ?67 160 l3? 129 123 ~:
12 di-cumyl peroxide 161 154 131 123 117 ~:~
2, 5-d~m-thyl-2, 164 157 134 126 120 ~ :
13 5-dl~t-butylparoxy) 1~ h-xane . - ~.
. . . . . _ 16 ' PeroxYk~tal~: ~:
. ~___ -- . . . . _ _ 17 1, l-di-t~nnylperoxy- 134 128 106 9g 93 cyclohexane _ _ ~ _ . .
lB . ~ . .
19 DiperoxYearbonates: . ~ . . _ di-~thylh~xylparoxy- 85 79 60 54 49 2 dicarbonate . - . _ . . .
2~ _ _ . _ _ _ _ 23 Diacyl PeroxideQ: . _ _ 2~ ~ 102 96 76 69 6 d~benzoyl peroxide 114 108 86 78 73 _ , . . - _ 26 ~ . . .
27 ~ _ _ - . ..
2~ t-butyl peroctoa~e 115 109 90 82 77 29 t-butyl perbenzoa~e 152 144 119 110 104 . . _ . .

31 Azo Compound~. . .
32 `I~N 105 9B 7B 72 65 3~

W094/02523 PCT/US93/064~C-9~

01 The amount of initiator to employ depends to a large extent 02 on the particular initiator chosen, the olefin used and the 03 reaction conditions. The initiator should generally be 0~ ~oluble in the reaction medium. The usual concentrations of 05 initiator are between 0.001:1 and 0.4:1 moles o~ initiator 06 per mole of polyolefin reactant, with preferred amounts 07 between 0.005:1 and 0.20:1.

09 In carrying out the process of the ïnvention, a single free -~
radical initiator or a mixture of free radical initiators 11 may be employed. For example, it may be desirable to add an ~;
12 initiator having a low decomposition temperature as the -~
13 mixture is war~ing to reaction temperature, and then add an 1~ initiator having a higher decom~osition temperature as the mixture reache~ higher reaction temperatures.
16 Alternatively, a combination of initiators could both be 17 added prior to heating and reaction. In this case, an 18 initiator having a high decomposition temperature would 19 initially be inert, but would later become active as the temperature rose.
2~ -~
22 The initiator may also be added over time. For example, if ~-23 an initiator is chosen with a short half-life, e.g., 5-20 - -~
2~ minutes, at the reaction temperature, then the initiator may be added over a period of time so that an adequate 26 concentration of free radicals will be available throughout 27 the reaction period to give improved yields of the desired 28 product.

In general, after the reaction is deemed complete, for 31 example, by NMR analysis, the reaction mixture is heated to 32 decompose any residual initiator. For a di(t-butyl) ~3 peroxide initiator, this temperature is typically about 3~ 160C or higher.

~94/02523 PCT/US93/0690~ ~
0 1 ~

--15-- ~ ~

01 A~ used herein, the term "multiple adduction" refers to the 02 alkenyl succ~nic anhydride reaction product of maleic 03 anhydride and polyolefin, wherein more than one molecule of ;-04 maleic anhydride is bonded to one molecule of polyolefin.
0s ~ ~, OC The average level of multiple adduction can be calculated 07 from the ~aponific~tion number (mg KOH per gram of sample) 08 and t~e activ~ content of the alkenyl succinic anhydride 09 product and the molecular weight of the starting polyolefin.
By ~average level of multiple adduction" is meant the 11 average number of succinic groups per polyolefin group in 12 the ~lkenyl ~uccinic an~ydride product. For example, an ~3 a~erage multiple adduction level of l.O indic~tes an average 1~ of one ~uccinic group per polyolefin group in the alkenyl ~uccinic anhydride product. Likewise, an average multiple 16 adduction level of 1.35 indicates an average of 1.35 17 succinic groups per polyolefin group in the alkenyl ~uccinic 18 anhydride product, and so forth.

The actives content of the alkenyl succinic anhydride 21 product is measured in terms of the actives fraction, 22 wherein an actives fraction of l.O is equivalent to 23 lOO percent actives. Accordingly, an actives fraction of 2~ 0.5 would correspond to SO percent actives.
26 The average level of multiple adduction for the alkenyl 27 succinic anhydride product of maleic anhydride and 28 polyolefin can be calculated in accordance with the 29 following equation:
31 Average Level of Mpo x P
32 M~ltiple Adduction (C x A) - (MMA x P) 3~

W094/02~23PCT/US93J06g~-9~

01 wherein P- saponification number of the alkenyl ;~ :
02~uccinic anhydride sample tmg KOH/g) OS A= actives fraction of the alkenyl succinic S anhydride sample ~:~

07 MPD = number average ~olecular weight of the ~
08 ~tarting polyolefin :-MMA Z molecular weight of maleic anhydride ~ ::
11 ~. .
12 C = conversion factor = 112220 (for conversion :~
13 of gram moles of alkenyl succinic anhydride 1~ per gram of sample to milligrams of XOH per ~ ~
gram of sample) ~ ;

17 The ~aponification number, P, can be measured using known 18 procedures, for example, as described in ASTM D94.
lg The actives fraction of the ~lkenyl succinic anhydride can 21 be determined from the percent of unreacted polyolefin 22 according to the following procedure. A 5.0 gram sample of ;~
23 the reaction product of maleic anhydride and polyol~fin is 2~ dissolved in hexane, placed in a column of 80.0 grams of silica gel ~Davisil 62, a 140 angstrom pore si e silica 26 gel), and eluted with l liter of hexane. The percent 27 unreacted polyolefin is determined by removing the hexane 28 solvent under vacuum from the eluent and weighing the 29 residue. Percent unreacted polyolefin is calculated according to the following formula:

32 Net Weight of 33 Percent Unreacted Polyolefin = Sample W~-ight x 190 ~094/02523 PCT/US93/~90~

21i901(3 ` ~

-17- ;~ ~
.' ~
01 The weight percent actives for the alkenyl succinic ~ ~
02 anhydr~de product is calculated from the percent unreacted ~ ~i 03 polyolefin using the formula~
0~ ~:
OS We ght Percent 100 - Percent Unreacted Polyolefin .

08 The actives fraction of the alkenyl succinic anhydride is ~ ;
0~ then calculated as follows:
, ,~
11 Actives Fraction z Weiaht Percent Actives ~2 13 The percent conversion of polyolefin is calculated from the ~:
1~ weight percent actives as follows: :~:
lS
16 wt. % x ~
actives .
1 Percent ~ + Mn~ x MADDJ
18 Conversion ~wt.. % x ~ oo _ wt~%
22 r l ~ [~. , J ~ L actlves ~

2~ wherein ~ = number average molecular weight of the starting polyolefin 27 Mn~ = molecular weight of maleic anhydride MADD = average level of multiple adduction It is, of course~ understood that alkenyl succinic anhydride products havinq high average levels of multiple adduction, as prepared by the process of the present invention, can 3~
. . .

- :''..',-01 also be blended with other alkenyl succinic anhydrides 02 having a lower average level of multiple adduction, for `~
03 ex~mple, a level of around 1.0, to provide an alkenyl 0~ succin~c anhydride product having an intermediate average OS level of mutliple adduction.

07 The following examples are offered to specifically ~;
08 illu~trate this invention. These examples and illustrations O~i are not be construed in any way as ii~iting the scope of -~
thi~ invention.
11 '~. ~ . .
12 ~XAMPLES -1~ Example 1 -lS
16 ~ 1000 grams (0.77 mole) of polyisobutene having a number 17 average molecular weight of 1300 and a methylvinylidene --18 isomer content of about 6 percent was charged to a reactor 19 and heated to 150C and stirred at 60 rpm with a mechanical ætirrer. To this was added a mixture of 11.2 grams ~0.077 21 mole) of di-t-butylperoxide, 120 ~ra~s of Chevron lOONR -22 diluent oil, and a total of 150.gO grams (1.54 moles) of 23 maleic anhydride over a four hour period. Then the reaction 2~ was held at 150C for an additional one hour. Any unreacted maleic anhydride was removed in vac~o at 1900C. The product 26 was then filtered. The resulting polyisobutenyl succinic 27 anhydride product had a saponification number of 47.7 mg 28 KOHtgram of sample, 31 weight percent actives, and an 29 average of about 2.06 succinic groups per pailyisobutenyl group. The conversion of polyisobutene was about 31 28.0 percent. The half-life of the di-t-butylperoxide free 32 radical initiator at the reaction temperature of 150C is 33 about 1 hour.
3~

,.:

~94/02523 PCT~US93/0690~
21i.~01~

01 E~mPle 2 03 The procedure of Example 1 wa~ followed, using 2648 grams ~ (2.04 moles) of 1300 molecular weight polyisobutene, S 389.4 grams (4.08 moles) of maleic anhydride~ 29.8 grams 06 (0.204 mole) of di-t-butylperoxide, and 318 grams of Chevron 07 100NR d~luent oil. The resulting polyisobutenyl succinic 08 anhydride product had a saponification number of 63.8 09 mg KOH/gram of sample, 45 weight percent actives, and an average of 1.87 succinic groups per polyisobutenyl group.
11 The conversion of polyisobutene was about 41.8 percent.

13 Example 3 1~ , .
~5 The procedure of Example 1 was followed, using 2167 grams 16 (1.67 moles) of 1300 molecular weight polyisobutene, 17 326.97 grams (3.34 moles) of maleic anhydride, 24.34 grams 1~ (0.167 moles) of di t-butylperoxide, and 260 grams of 19 Che~ron 100NR diluent oil. The resulting polyisobutenyl succinic anbydride product had a saponification number of 21 63.8 mg KOH/gram of sample, 45 weight percent actives~ and 22 an average of 1.87 succinic groups per polyi~obutenyl group.
23 The conversion of polyisobutene was about 41.8 percent.
2~
Example 4 ~6 27 The procedure of Example 1 was followed, using 1600 grams 28 (1.23 moles) of 1300 molecular weight polyisobutene, 193 2~ grams (1.97 moles) of maleic anhydride and 28 grams (0.1~2 mole) of di-t-butylperoxide. In addition, 300 grams of a C9 31 aromatic solvent was used instead of the Chevron 100NR
32 diluent oil and the r~a~tion time was 14 hours instead of 5 33 hours. The resulting polyisobutenyl succinic anhydride 3~ -,:, .:.. ..

W094/02523 PCT/US93/069~--9~

01 product had ~ saponification number of 84.2 mg KOH/gram of 02 sample, 60.4 weight percent actives, and an average of 1.84 03 succinic groups per polyisobutenyl ~roup. The conversion of 0~ polyisobutene was about 57.3 percent.

06 Example 5 08 Th~ procedure of Example 1 was followed, using 60,700 gra~s 09 (46.7 moles) of 1300 molecular weight polyisobutene, 4,560 grams (46.7 moles) of maleic anhydride and 681.7 grams ~4.67 11 moles) of di-t-butylperoxide. No solvent was used and the 12 reaction time was 11 hours. The resulting polyisobutenyl 13 succinic ~nhydride product had a saponification number of 1~ 46.5 mg XOH/gram of sample, 44~4 weight percent actives, and an av2rage of 1~34 succinic groups per polyisobutenyl group.
16 ~ ~he conversion o~ polyisobutene was about 42.0 percent.
17 ~ -18 Example 6 ~0 The procedure of Example 1 was followed, using 61,900 grams 21 (47.6 moles) of 1300 molecular weight polyisobutene, 22 9,332.6 grams (95.2 moles~ of maleic anhydride and 695.2 23 grams (4.76 moles) of di-t;butylperoxide. No solvent was 24 used and the reaction time was 14 hours. The resulting polyisobutenyl succinic anhydride product had a 26 aponification number of 94O5 mg KOH/gram of sample, 65.4 27 weight percent actives, and an average of 1.92 succinic 28 groups per polyisobutenyl group. The conversion of 29 polyisobutene was about 62.3 percent.
31 ExamPle 7 -~

33 The procedure of Example 1 was followed, using 42,800 grams 34 (19.5 moles) of a polyisobutene having a number average -~

~094/02523 PCT/US93/0690~
21i9~310 01 molecular weight of 2200 and a methylvinylidene isomer 02 content of lecs than 2 percent, 4,294 grams (43.8 moles) of 03 maleic anhydride and 523 grams (3.58 moles) of di-t-04 butylperoxide. No solvent was used and the reaction time 05 was 14 hours. The resulting polyisobutenyl succinic OC anhydride product had a saponification number of 41.7 mg 07 KOHtgram of ~ample, 59 weight p~rcent actives, and an 08 average of 1.46 ~uccinic groups per polyisobutenyl group.
09 The conversion of polyisobutene was about 57.5 percent.
~0 11 COMPARATIV~ EXAMPLES

~3 Comparative Exa~ple 1 1~ .
lS This example follows the procedure of U.S. Patent No.
16 ~3,367,864, Example I, part (1).

~ To a 2-liter 3-necked flask equipped with a thermo~eter, 19 nitrogen inlet, condensor and stirrer was added 400.0 gram~
(G.355 mole) of a polyisobutene having a number average 21 molecular weight of about 1100 and a methylvinylidene isomer 22 content of about 2 percent, 38.27 grams (0.39 mole) of 23 maleic anhydride, 6.89 grams (0.0~7 mole) of 2~ di-t-butylperoxide, and 210 ml. of toluene as a solvent.
This mixture was stirred and heated at reflux (110C) for a 26 period of 30 hours. Then the toluene was removed in vacuo, 27 and the product was dissolved in 250 ml. o~ hexa~e and 28 f iltered to remove the unreacted maleic a~hydride. The 29 hexane was then removed in vacuo. The resulting polyisobutenyl succinic anhydride product had a 31 saponification number of 29.2 mg KOH/gram of sample, 32 16.24 weight percent actives, and an average of about 33 2.09 succinic groups per polyisobutenyl group. The 34 conversion of polyisobutene was about 14.1 percent. The W094/02s~3 PCT/US93/06 ~9~ -22-half-life of the di-t-butylperoxide free radical initiator 02 ~t the reaction temperature of 110C is about 120 hour~.

~ Comparative Example 2 06 The procedure of Comparative Example 1 was repeated. The 07 resulting polyisobutenyl succinic anhydride product had a 08 saponification number of 7.7 mg KOH/gram of sample, 09 4.7 weight percent ~ctives, and an average of about ---10 1.87 succinic groups per polyi~obutenyl qroup. The ~
11 conversion of polyisobutene was about 4.1 percent. ~ -13 5 ~ y~xample 3 1~ , lS The procedure of Comparative Example 1 was followed, using ~-~
~6 ' 330 grams (0.35 mole) of a polyisobutene having a number 17 average molecular weight of about 950 and a ~ethylvinylidene 18 i~omer content of about 2 percent, 32.3 grams (0.33 moles~
19 of maleic anhydride, 5.8 grams (0.040 mole) of 20 di-t-butylperoxide, and 210 ml. of toluene as a solvent. i~
21 The resulting polyisobutenyl su~cinic anh~dride product had 22 a saponification number of 87.3 mg KOH/gram of sample, 23 48 weight percent actives, and an average of about 2~ 1.83 succinic qroups per polyisobutenyl group. The conversion of polyisobuten~ was about 43.7 percent.
2~
27 Comparative Example 4 29 The procedure of Comparative Example 1 was followed, using -390 grams (0.30 mole) of polyisobutene having a number 31 average molecular weight of about 1300 and a 32 methylvinylidene isomer content of about 6 percent, ~3 3Z.3 grams (0.33 mole) of maleic anhydride, 5.8 grams 3~ ~0.040 mole) of di-t-~utylperoxide, and 210 ml. of toluene w?94/02523 PCT/US93/0690~
21 1 ~3 Dl D

0~ as a solvent. The resulting polyisobutenyl succinic 02 anhydride product had a saponification number of 53.9 mg 03 KOH/gram of sample, 43 weight percent actives, and an 0~ average of about 1.63 succinic groups per polyisobutenyl 05 group. The conversion of polyisobutene wa8 about 06 40.2 percent.

08 Comparative ExamDle 5 ~ Th~ procedure of Comparative Example 1 was followed, using 11 330 grams (0.35 mole) of 950 molecular weight polyisobutene, ~2 32.3 grams (0.33 mole) of maleic anhydride and 5.8 grams ~3 (0.040 mole) of di-t-butylperoxide. In addition, 210 ml. of 1~ xylene was used as a solvent instead of toluene and the lS reaction temperature was 114~C instead of 110C. The 16 ' resulting polyisobutenyl succinic anhydride product had z 17 ~aponification number of 80.9 mg KOH/gram of sample, :
~8 43 weight percent actives, and an average of about 1.90 :-19 succinic groups per polyisobutenyl grsup. The conversion of polyisobutene was about 38.7 percent.
22 Comparative Examples 1-5 show that the use of a di-t~
23 butylperoxide initiator at the reaction temperature of 110C
24 gives conver~ions of only 4.1 to 43.7 percent, even at the :~
25 relatively lon~ reaction time of 30 hours.
~6 27 Comparative Example 6 29 To a 2-liter flask equipped with a stirrer, thermometer and condensor was added 384.6 grams (0.405 mole) of a 3~ polyisobutene having a number average molecular weight of :
32 950 and a methylvinylidene isomer content of about 2 33 percent, 119 grams (1.215 moles) of maleic anhydride and 250 3~ ml. of toluene as a solvent. This mixture was heated to W094/02523 PCT/US~3/069Q~ ~

9~

. . ~
01 reflux (110C) and to this was added a total of 15.5 grams 02 (0.081 mole) of alpha, alpha'-azo-bisisobutyronitrile (AIBN) 03 over a period of four hours. The reaction was heated for a 04 total of six hours. The product was then cooled, placed 05 into a separatory funnel and the top phase was ~eparated and 06 filtered to remove excess maleic anhydride. The toluene w~s 07 then removed in vacuo. The resulting polyisobutenyl 08 succin~c anhydride product had a saponification number of 09 24.3 mg KOH/gram of sample, 13 weight percent actives, and i0 an average of 1.89 succinic groups per polyisobutenyl group.
11 The conversion of polyisobutene was about 11.1 percent. The 12 half-life of the AIBN free radical initiator at the reaction 13 temperature of 110C is about 3 minutes. This example ~hows 14 that the use of a free radical initiator having a very short half-life at the temperature of reaction results in a low 16 ' conversion of polyolefin.
17 ~-~

Claims (16)

WHAT IS CLAIMED IS:

1. A process for the preparation of an alkenyl-substituted succinic anhydride wherein the alkenyl substituent has number average molecular weight of from about 500 to 5000 and the average number of succinic groups per alkenyl group is greater than 1.2 which comprises reacting a polyolefin having an alkylvinylidene isomer content of less than about 10 percent and a number average molecular weight of about 500 to 5000 with maleic anhydride in the presence of a free radical initiator at a temperature in the range of about 80°C
to 220°C for a period of less than 20 hours, wherein the molar ratio of maleic anhydride to polyolefin is about 1.0:1 to 9:1, and wherein the half-life of the decomposition of the free radical initiator is about 5 minutes to 10 hours at the reaction temperature.

2. The process according to Claim 1, wherein the alkenyl succinic anhydride produced has an average of greater than 1.3 succinic groups per alkenyl group.

3. The process according to Claim 2, wherein the alkenyl succinic anhydride produced has an average of greater than 1.3 to about 4.0 succinic groups per alkenyl group.

4. The process according to Claim 3, wherein the alkenyl succinic anhydride produced has an average of greater than 1.3 to about 2.5 succinic groups per alkenyl group.

5. The process according to Claim 1, wherein the polyolefin has a number average molecular weight of about 700 to 3000.

6. The process according to Claim 5, wherein the polyolefin has a number average molecular weight of about 900 to 2500.

7. The process according to Claim 1, wherein the polyolefin is a polybutene or polypropylene.

8. The process according to Claim 7, wherein the polyolefin is a polyisobutene.

9. The process according to Claim 8, wherein the polyisobutene has a number average molecular weight of about 900 to 2500.

10. The process according to Claim 1, wherein the free radical initiator employed is a peroxide-type free radical initiator.

11. The process according to Claim 10, wherein the peroxide-type free radical initiator is di-tert-butyl peroxide.

12. The process according to Claim 1, wherein the molar ratio of maleic anhydride to polyolefin is about 2:1 to about 4:1.

13. The process according to Claim 1, wherein the reaction is carried out at a temperature in the range of about 140°C to about 180°C.

14. The process according to Claim 13, wherein the reaction is carried out at a temperature in the range of about 145°C to about 165°C.

15. The process according to Claim 1, wherein the reaction is carried out for a period of about 1 to 15 hours.

16. The process according to Claim 1, wherein the reaction is carried out in the absence of a solvent.