CA2119012A1

CA2119012A1 - Two-step radical catalyzed process for the preparation of alkenyl succinic anhydride

Info

Publication number: CA2119012A1
Application number: CA002119012A
Authority: CA
Inventors: James J. Harrison; William R. Ruhe, Jr.
Original assignee: Individual
Current assignee: Chevron USA Inc
Priority date: 1992-07-23
Filing date: 1993-07-23
Publication date: 1994-02-03
Also published as: EP0605715B1; DE69318528D1; JPH07501832A; EP0605715A4; WO1994002571A1; DE69318528T2; JP3285356B2; EP0605715A1; US5286799A

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: (a) 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 100 ·C to 220 ·C to provide a mixture of alkenyl succinic anhydride having an average of greater than 1.2 succinic groups per alkenyl group and unreacted polyolefin, wherein the conversion of polyolefin is from about 30 to about 65 percent, and (b) reacting the mixture of alkenyl succinic anhydride and unreacted polyolefin with maleic anhydride at a temperature in the range of about 200 ·C to 250 ·C to thereby provide an alkenyl succinic anhydride having an average of greater than 1.2 succinic groups per alkenyl group, wherein the total conversion of polyolefin is about 5 to 40 percentage points higher than the conversion in step (a).

Description

V~ 9~/~2571 PCI/U~93/06915 ` 2119~12 01 q~O--8TEP ~ RADI~ A~AI,Y8ED ~ROCBR8 02 ~0~ R~P~aTION OF
~3 I~X~Y~ 8~CINIC ~YD~IDI~

S BAÇXGROUND OF l~IEIN

07 The present invention relates to a pros::e~s f or preparing 08 composition~ which are useful as inter~ediates f or 09 - dispersants used in lu3~ricAting oil compositions or as dispersants themselves. In addition, some of the 11 compositiorls prepared by the present process are useful in 12 ~e preparation of high molecular weight dispersarlts which 13 ha~ve ~;uperior dispersant propertie~ f or dispersing sludge :14 arld varnish. Such high mol~cular weight dispersants also ~LS ~ adv2~tageously impar~ f luidity modifying prop~rties to 16 ~ lu:~i~:ating oil compositions which are suf f icient to allos~
:17: eli~ina~ion o~ ~;ome proportion of vi~;c:osity index improsrer fr~m lau1tigrade lubricatins~ oil co~positions which contain 19 ~ the~3e~ di~p~r~ants.

2 0 ~ ~ ~
2 ~ It i~ lcnown irl the art that alkenyl-subs~itut~-d ~UCCilliC
2~ anhydrides have been usç~d as disper~ants. Such 23 ~ alkenyl- ubstituted succinic ar~hydrides have been prepar~3d 24 ~by two dif~eren~ processes, a thermal process (see, e.g., U~.S. Patent No. 3,361,673) and a chlorination process (see, 2 C e . g ., U . S . Patent No . 3 , 172 , 892 ) . The polyisobutenyl ~7 succinic anhydride ( "PIBSA" ) produced by the thermal process 2~ has been characterized as a monomer con~aining a double bond 2 ~ in th~ product . Although the exac~ structure of chlvrination PIBSA has not been definitiYely determined, the 3 ~ chlorination process PIBSA materials have been characterized 32 as monomers containing either a double bond, a ring other 33 than succinic anhydride ring and/or chlorine in th~ product.
34 ~ (See J. Weill and B. Sillion, "Reaction of Chlorinated W094~02~71 PCT/US93/06g1~

L9U~'l 01 Polyi~o~utene with Maleic Anhydride: Mechani~m Catalysis ~y 02 Dichloramal~ic ~nhydride", Revue de 1'Institut Francai~ du 03 Petrole, Vol. 40, No. lg pp. 77-89 (January-February, 0~ 1985~.] Such compositions inelude one-to-one monomeric 05 adducts (see, e~g., U.S. Patents Nos. 3,219,666; 3,381~022) 06 as well ~8 adducks having polyalkenyl-derived ~ubstitu~nts 07 adducted with at least 1.3 succinic groups per 08 polyalk nyl-derived substituent (see, e.g., U.S. Patent 0~ No. 4,234,435).
~1 Commonly assigned International Patent Application 2 No. PCT/US89/04270, Publication No. W0 90/~3359, dated 13 ~pri~l 5, 1990 and entitled "Novel Polymeri~ Disper~ants 14 ~:H2ving Alternating~Polyalkylene and Succinic Groups"
I5~ di~c}oses copolymers prepared by reacting an unsaturated 6 ac~dic~reactant, ~uoh:as maleic anhydride, with a high 17 ~Dolecular weigh~olefin, such as polyisobutene, in th~
a8 : pres~nee of a fsee radical ini~iator, wherein at least about 9; ~2~0 perce~t o~thé~total;high molecular weight olefin comprises~ an ~lk~lvinylidene isomer and wh~rein the high 2~ molecular weight ol~fin has a suf icient number of carbon 22: ~;atoms sueh that:;th resulting copolymer is soluble in 23 lubricating oil~.
24 ~
U.S. Patent No. 4,234,435 to Meinhar~t ~t al., assigned to 26 The Lubrizol Co~porati~on, discloses substituted succinic 27 a~ylating agents:derived from polyalkanes, such as 28 polybutene,~ànd a dibasic carboxylic reactant, such as 2~ maleic acid or anhydride, wherein the polyalkenes have a number average molecular weight of about 1300 to 5000 and a 31: ratio of weight average to number average molecular weight 32 of about 1.5 to 4. These acylating agents are further 33 characterized by the presence of an average of at least 34 1.3 succinic groups for each equivalent weight of ~N~94/02571 ~ 1 1 90 1 2 PCT/US93/06915 01 sub~tituent group. Meinhardt et al. teach that such 02 acylating agents ar~ prepared by heating the polyalkene and 03 carboxyli~ reactant with chlorine in ~ one-step proc~ or, ~ alt~r~atively, by ~ir~t reacting the polyalk~ne with S chlorine and then r~acting the resulting chlorinated 06 polyalkene wit~ the carboxylic reactant. This patent 07 ~urther te~ches that such substituted succinic acylating Q8 agents and their derivatives are useful lubricati1g oil 09 disp~rsant additives which also exhibit viscosity index improving prop~rties.

~2 U.S. P~te~t No. 4,~73,004 to Beverwijk et al., assigned to 13 S~ell OiI Compa~y, disclsses an alkyl or alkenyl-substituted succinic anhydride, wherein the alkyl or alkenyl group on 5 ~ ~he anhydride has a number average mol~cular weight of from a6 6~0 to 1~00 and wh~rein the aver~ge number o~ ~ucci~ic ~7 ~ groups per alkyl or alkenyl group i5 betw~n l.4 and 4~0 8 B~erwijk et al. teach th~t these alkyl or 1~ alkenyl ubstituted ~uccinic anhydrid~s can b~ prepared by 2~ ~ixing a polyolefin with maleic anhydride and passing :21 chlorine through the ~ixtur~, or by r~acting a chlorinated 22 polyol~fin wi~h~alei~ anhydride. B~verwijk 2t. al. furth~r 23 tea~ that the suc~inimide derivativ~s of such substitutad 2 ~ 5uccinic anhydrides are useful d~sper~ant additive~ for X5 lubri~2tin~ oils.
2~
27 U~S. Patent No. 3, 367,B64 to Elliot et al., a~signed to ~8 Castrol Limited, disclos~s in Example I thereo~ the 2~ preparation of a polyisobutenyl succinic anhydride by the 3o reaGtion of about a 1: 1 molar ratio of polyisobutylene and 3l maleic anhydride in refluxing toluane and in the presence of 32 a di tertiary-butyl peroxide free radical initiator. Elliot 33 et al. further teach that the succinic anhydride product 3~ produced by this method is similar to the product obtained WO94/0~571 PCT/U~3/06glS~

9~

01 ~y th~rmally r~acting polyi~sbutylene and ma~eic anhydride 02 ~t 240C ~or 30 hour.
~3 ~ It h~s g~nerally been recogni~ed in the art that the 05 polyi~obutenyl succinic anhydride prepared by employing a 06 conv~ntional thermal process is primarily a monomeric 07 one-to-one adduot, that is, havin~ about one succinic group 08 per polyiaobutenyl group in the product. However t recent ~ analysis o~ a numb~r o~ polyisobutenyl succinic anhydride products produced by following the free radical-initiated 1 proc~ of Exampl~ I o~ U.S. Patant No. 3,367,864 has 12 r~ulted in a inding ~hat such products are mon~meric a3 a~duct~ containing an av~rage of about 1.~ or greater 14 ~uccinic groups~per polyisobutenyl group.

16 : Mor~over, Europ~an Patent Application Publication 17 ~ No.:0,:355,89~5 A2~, published F~bruary 28, 1990, di clos~s a 8 ~ psoce s or~the~ preparation of polyol~fin-substituted 9 ~ ~8~ cinic a~nhydride~ in which the aYerage molar ratio of ~succinic groups to polyolefin chains is greate~ than .3 t~ which comprises heating a polyolefin wit~ at least 22 ~ a molar ~xce~s of~maleic anhydride, wherein the polyolefin 23 emp~yed ~ontain~ at least 70 p~rcent of the terminal 24 groupings in a structure having an alpha olef~nic bond or structures in eq~ilibrium with uch alpha olefinic 26 structures~ Thus J this European pat~nt application teaches 27 that greate~ than 1.3 succinic groups per polyolefin group 28 can be obtained when the polyolefin employed i5 one wherein 29 th~ pr~dominant isomer is an alkylvinylidene.

~9~/02571 2 1 ~ 9 0 1~ PCT/US~3/06915 01 ~=i 03 ~h~ pr~ent invention provides a two-step process for ~h~
04 preparation of an alkenyl-substituted succini~ anhydride 05 wherein th~ alkenyl ~ubstituent has a number aver~ge 06 molecular w~ight ~f from about 500 to 5000 and the average 07 number of ~uccinic groups per alkenyl ~r~up is greater than 08 l.2 which mpri~e~:

~a) reacting a polyolefin having an alkylvinylide~e isomer 11 content of léss than about $0 peraent and a num~er 12 ~ average molecular weight o~ about 500 to 5000 with 3~ mal~ic anhydride in the presence of a free r~dical 4 ~ ini~iatoF ~at a~t~mperature in the ra~ge of ab~ut lOO~C
:~ to~220C~to provide~a mixture of alkenyl succinic 16 ;: a~hydride ha~ing~an averag~ o~ grea~er than 17 ~ 1.2~sùccinio~:groups per alkenyl group and unre~cted 8~ : polyolefin,~:~wherein~the co~ver ion ~f polyolefin is, 9:~ from about~:30~to about 65 percen~, and (b)~:~r~acting~the mixture~ of alkenyl succinic anhydride and 2~ ;polyolefin~with~maleic anhydride at a temperature in 23 ~ the;:rànge:~of:~ about 200C to 250C to there~y provide an : 24 :~ :~ alkenyl succinic anhydride~ha~ing an avP-rage of greater than 1.2 suc inic groups per alk~nyl group, wh~rein the :`26 ~otal co~version of polyolefin is about 5 to 40 27 percentage points higher than the conversion in 28 step (a). ~ :
2~ ~
Amony other ~actors, the present inYention is based on the 31. discovery that certai~ alkenyl-substituted succi~ic 32~:: anhydrides containing an average o~ greater than 33 1.2 succinic groups per alkenyl group can be effectively 34 prepared in high yields and conversio~s by employing a W094/02571 PCTJUS93/06915~i 9~

01 unique two-~tep proce~s which does not involve the use of 02 chlorine, there~y resulting in a product havin~ improved 03 en~ironment~l properties.

Q5 The average numb~r of surcinic groups per al~enyl group i~
06 th~ alkenyl 8ucCinic anhydride produced by the present ~7 process is grsater than 1.2, preferably gr~ater than 1.3, 08 mor~ preferably greater than 1.3 to about 4.0, and most Q9 preferably greater than 1.3 to about 2.5.
11 Sui~able polyolefins for use in preparing the alkenyl lZ : uc~inic anhydride products will have a number av2rage 13 molecular weight of about 500 to 5000, pre~erably ~rom about ~ 700 to 3000,: and ~ore preferably, from about 900 to 2500.
Generally, such~polyolefins will contain at lea~t about 35 carbon atoms, pre~erably about 50 carbo~ ato~s or 17 greater. Preferred polyolefins are poly~utene and .
I8 polypropylene:, par~icularly polyisobute~e. Suitable ~9 ;polyolefins will a:lso contain an alkylvinylidene isom~r ~ ~ con~ent of le s~than about 10 percent.
21:~:
2~ The ~uccinic anhydride products prepared by the process of 23 ~ the in~ention~are use~ul as dispersants the~elves and also 24 as intermedi~t~s~in the preparation of other dispersant additi~es havlng improved dispersancy and/or detergency 26 properties when employed in a lubricating oil.

28 The products produced by the instant process can also be 29 us~d to form polysuccinimides which are prepared by reacting the alkenyl succinic anhydride with a polyamine to give a 3l polysuccinimide. These polysuccinimides are useful as 32 di~persants andlor detergents in fuels a~d oils. In 33 ~ddition, these polysuccinimides have advantageous viscosity 34 modifyi~g properties, and may provide a viscosity index WO94/02571 PCr/US93~06915 01 credit ("V.I. Credit") when used in lubricati~g oils, which 02 may permit eli~in~tion of some portion of viscosity index 03 impro~er ("V.I. Improver") from multigrade lubricating oil~
0~ containing the same.

06 ~oreover, the ~uccinic anhydrides prepared by the present 07 proc~ss can be employed to make modified poly~uccinimides 08 wherein one or more o~ the nitrogens of the polyamine 0~ aomponent is ~ubsti~uted with a hydrocarbyl oxycarbonyl, a ~ hydroxyhydrocarbyl oxycarbonyl or a hydroxy l? poly(o~yalkyl~ne)-oxycarbonyl. Thes modified 12 poly uccin~mides are improved dispersants and/or detergents for use in fuels or oils~
1~
~S Accordingly, the alkenyl succini~- anhydrides made by the 16 p~ent proc~s are use~ul in providing a lubricating oil 17~ composition comprising a major amount of an oil of 8 ~lubri~ating vi~cosity and an amount of a ~uccinic anhydride, l9 poly~uccinimide or modified uccinimide additive sufficient to provide dispersancy an~/or detergen y. These adaitives 2~ ~ay al~G be formulated in lubricating oil concentrates which 22 cont~in about 10 to about 50 weight percent of the additive.

24 Furthermore/ the alkenyl succinic anhydrides formed by the present prccess can be used to provide a fuel compo îtion 26 ~ompri~ing a major porti~n of a fuel boiling in a gasoline 27 or diesel range ~nd an amou~t of succinic anhydride, 28 polysuccinimide or modified ~uccinimide additive sufficient 29 to provide dispersancy and/or detergency. These additives can also be used to make fuel concentxates comprising an 31 inert stable oleophilic organic sol~ent boiling in the range 32 of about 150F to about 400F and from about 5 to about 33 50 weight percent of such additive.

W~ 94/~2~71 PCr/US93/06glS ~

9~

DET~ D DESRIP~ION_C)F~HE_INVEN~ION

03 The hig~ molecular weight polyo}ef in~; used in the ~ prepara~ion of the instant alkenyl 8UCCirliC anhydrides are ~ of suf ~iciently long chain length so that the resulting 06 co~po~ition is ~oluble in and compatible with mineral oils, 07 fu~ls and ~he like. Thus, the polyol~in will typically 08 c:ont~in about 3 5 carbon atoms or gr~ater, pref era~ly about 09 50 c:arbon atoms or greater.
1~
11 Such high molecular weight polyolef ins are generally 12 mixtures of mol~cllles; having dif f erent molecular weights and 13 can have at least one branch per 6 carbon atoms along the ~ chain, pref er~bly at least one branch per 4 c:arbon atoms 15 alorlg the chain, and move preferably about one branch per 1~ 2 carbon atoms along t:he chain. These branch~d c:hain ~: :
17 ole~ins may aon~éniently comprise polyalkenes pr~pa~ed by 18 thg~ polymerization~of olefins of from 3 ~o 6 carbon atom~, 9 and pre~er~bly from olefin~ o~ from 3 to 4 carbon at~ms, and ~ore preferably fr~m pro~ylen~i or isobutyl~ne. The' 2i ad~ltion polymerizable olefin~ employed are norma~ly 22 : l~ole~ins. ~he branch may be o~ ~rom 1 to 4 carbon atoms, 23 ~ore usually of from l to 2 carbon atoms and pref-rably 2~ methyl.

26 The polyol~fins employed in the procesi of the present 27 invention may be prepared by conventional techniques well 2B known in the art, ~uch as aluminum chloride-catalyzed 29 poly~erization of lower olefins.

3l Pxeferred polyo~efins are polyisobutenes having ~um~er 32 average molecular weights of about 500 to about 5000, more 33 preferably about 700 to about 3000. Especially preferred ~ ~W~94/025?1 PCT/US93306915 2119~1~

01 are kho~e polyisobutene~ having numb~r average molecular 02 weights of ~bout 900 to 2500.

0~ Th~ polyole~in~ employed in the instant proc~ss will also 05 have a low alkylvinylidene isomer content, that i~, less 0~ than about ~0 percent alkylvinylidene. As used herein, the 07 t~rm ~'alkylvinylidenel' or "alkylvinylidene isomer'i i~ meant 08 to indicate ~lefins having the ~ormula:
~9 Rl ~1 R21CH2 3 :
14 wherein R1 i8 lower alkyl of 1 ~o about 6 carbon atoms and R2 is a polyolefin residue. Consequently, high lC :;alkylvi~ylidene polyolefins having greater than about a 17 ~o per~ent alkylvinylidene content, such as the commercially available Ultravis type of polyisobu~ene, are unsuitable for u~e iD the procesq inven~ion~ since such materials tend to :Porm copolymers with maleic anhydride in the presence of a Z1 free ~adical initiator.
2~ ~
In general, the ratio of weight average molecular weight 24 (Mw3 to number average molecular weight (MN), tha~
~W~MN~ for the polyolefins employed in the present ~ invention will faIl within the range of about 1.1 to 4Ø
28 The MW and MN ~alues for the polyolefins used in this 29 invention are determi~ed by gel permeation chromato~raphy (GPC) as described, for example, in U.S. Patent 31 NoO 4,234,435 to Meinhardt et al.

33 As noted a~ove, the present invention relates to a unique 34 two-step process for preparing an alkenyl succinic anhydride WO 94/02571 PCr/V~3/0~915 ~so.

9~

01 }la~ring greatar th~n 1.. 2 succinic groups pç~r alkenyl group, 02 wher~in the f irst step introlves reacting a polyolef in wîth 03 maleic anhydride in the presence of a free radical initiator 04 to ~ive a ~ixture of unreacted polyolef in and alkenyl 9S succinic anhydride having an aYerage of greater than 06 1. 2 su ::cinic group per alkenyl group, wherein the conYersion 07 of polyolefin is from about 30 to about 65 perc~nt. Then, ~8 in the second st~p, the mixture of unreactsd polyolef in and 03 alkenyl ~;uccinic anhydride from the first ~tep is reac:ted ~ O with additional maleic anhydride under thermal conditions to 11 give the d~sired produc:t having an average of ~reater than 12 1 . 2 ~;U~GilliC: groups per alkenyl group, and wherein the total 3 co~v~ræiorl o polyolef in is about 5 to 4 0 p~rcentage points higher than the conversion in the f irst ~tep.

Acc:ordingly t in the î irst step of the instant process, the 17 polyo}e~in and maleic anhydride are reacted in the presens:e 18 of a free radical initiator. The temperature of thia 19 reaction will generally be in the range of about 100C to 20: 220C, ;preferably about 120C to 1~0C. The time o~
21 rq~ac:tion will Yary~ depending in part upon the reaction 22 ~tem~era~ure, but will generally Pall withi~ the range of 23 ~abo~t 2 to 30 hours, preferably about 4 to 20 hours. The 2~ reaction pressure can be atmospheric, ~lthough higher pressures up to about 50 psig are preferred. The molar 26 ratio of maleic anhydride to polyolefin will generally be 27 about 1:1 to about 9.1. Upon completion, this reaction will 28 typically result in about a 30 to about 65 percent 29 conversion of polyolefin to an alkenyl succinic anhydride product having an average of greater than 1.2 succinic 31 groups per alkenyl groupO

33 In the second step of the present process, the crude 34 reaction mixture of alkenyl succinic anhydride and unreacted ~094/~2571 2 ~ PCT/U~3J06915 0~ polyolefin from the first step ifi further r~acted with 02 additional maleic anhydride under thermal aonditions. The 03 te~pera~re o~ this re ction wi~l generally be in ~he range 04 of ~bout 200C to ~50~C, preferably about 220C to about 0s 240C. The reaction time is suitably between about 2 and 06 lO hours, preferably betw~en about 4 and 8 hours~ The 07 r~action pr~s~ure can be atmospheric, although higher 08 pr~sures up to about 50 ~sig are preferred. In general, 09 about l to ~ moles of maleic anhydride will be employed per mol~ of the mixture of a}kenyl succinic anhydride a~d l unreacted polyolefin from the first step. The maleic 12 ~nhydride employed in the second ~t~p can be either excess 13 maleic anhydride left over from the firs~ step or l4~ additionally added maleic anhydride. The reaction will normally proceed:to give a conversion of polyolefin to the 6 d~sired alk~nyl~succinic a ~ ydride product about 5 to 17 ~4~0 per~entage points higher than the conversion in the fir~t 18 step.

20~ : The:reaction 1nvolvsd in either the first or s~cond'step of 21: :th~ present proc~ss can be carried out in the pre~ence or ;22 :: ~sence of a ~olvent which is i~ert to the reaGtion taking 23 :~ place. Wh~n~employed, suitable solvents include toluene, 2~ : xylene, Cg aromatics, neutraI oil, and the like~
Preferably, both reaction~ are carried out without a 26 solvent.
27~ :
2~ ~ The alkenyl succinic anhydride produced by this twostep process will contain an average of greater than about 1.2 succinic groups per alkenyl group, preferably greater than l.3, more preferably greater than l.3 to about 4.0, and 32 most preferably greater than l.3 to about 2.5 succinic 33 groups per alkenyl group.

g4/(12571 P~I~/US93/06915.~s?`"~

?, -12-01 In ~eneral, the f irst step of the process of the present 02 invent:ion c~n be initiated by any free radic~l initiator~, 03 Such initiators are well known in the art. Howev~r, the ~ choice of free radic::al initiator may be influenced by the 05 reaction temperature employed.
OS
07 Preferably, the half-life of the decomposi ion of the free Q8 radical initiator at the temperature of reaction will be in 09 th~ range o~ about 5 minutes to 10 hours, more preferably, about 10 ~inute to 5 hours, and most preferably, about 10 11 mimltes to 2 hours.
1~ :
13 ~ The: pr~ferred free-radical initiators are the peroxide-type initiators and azo-type initiators.
5: ; :`
6 The peroxide-typ~ free-radical initiator can be organic: or 17~ ~ inorgarlic" the ~organic :having the general formula- R300R3~
a8 wh~r~ R3 is any organic radieal and :R3~ is select~d from the 19 ~group :consisting o~ hydrogen and any organic radical. Bo~h 20 ~ nd ~3t can ~;e organic radicals, preferably hydrocarbon, aroyl ~ ~nd ac:yl r~dicals, carrying, i~ desired, sub~;tituents 22 sucp as halogens, etc. Preferred peroxides include 3 di-~:ert-butyl:peroxide, tert-butyl peroxybenzoate, a~d 24 dicumyl peroxide.
':: j 26 Examples of other suitable peroxides, which in no way are limiting, inc~ud~e benzoyl peroxide; lauroyl peroxide; other 28 tertiary butyl peroxides; 2,4-dichlorobenzoyl peroxide;
~ 29 tertiary butyl hydroperoxide; cumene hydroperoxide; diacetyl `~ 3 peroxide; ~cetyl hydroperoxide; diethylperoxycarbonate;
:~: 31 ~ertiary butyl perbenzoate; and the like.
: 32 .

`~94~02571 PCT/U~93/06915 01 The azo-type compounds, ~ypi~ied by alpha, 02 alpha' azo-bi~issbutyronitrile ~AIB~), are al~o well-know~
03 free-radical promoting mat~rials. Th~se azo compounds can Oq be defin~d a~ those having present in the molecul~ the 05 group -N-N wherPin th~ balances are satisfi~d by organic 06 r~dical~, at l~ast one of which is preferably attached to a 07 terti~xy carbon. Other suitable azo compounds include, but 08 are not limited to, p-bromobenzenediazonium ~luoborate;
~ p-tolyldiazoaminobenzene; p-bromobenzenediazonium hydroxide;
azomethane and ph nyldiazonium halides. ~ suitable list of 11 azo~type compounds can be found in U.S. Patent 12 No. 2,~51,8~3, issued May 8, 1951 to Paul Pinkney.
~3 ~4 The hal~ lif~ values for known free radical initiator~ at various tQmperature are readily available ~rom the 16 lit~ratur~. S~e~ ~or ~xample, C. Walling, ~'Free Radicals 17 in Solutio~l, John Wiley and Sons, Inc., New York (1957~
18 Alter~atively, ~he half-life values are avail~bl~ ~rom the 19 variou~ supplier~ of free radical initiators, such as Witco, Atochem, Lucido~, Phillips Petroleum, and the like.' Table 1 21 li8t~ ~he half~ e temperatures for a number of free 22 radical initiators at a given half-life. The half-life : ~ , ~23 temperature is the temperature required for a free radical 2~ initiator to exhibit a specified half-life. As a rule, the higher the half~life temperatur~, the lower the half life of 26 the free radical initiat~r.
~7 3~

WO 94/02571 PCr/US93/Ob915 ,~

~ 14-01 Table 1 H21f~Life Temperature~ of Varicu~ Free ~3Rad~cal I~it~atora ~t Spæcif~2d Ha1~-Live~
04 ~
Ha1f-Life TemPerature~_C, 06:
In~t~ator 5 ~ins.10 min~.2 Br~.5 Hr~. 10 ~r~.
~7 ~
08 1~L~ lanY~:5 di-t~butyl peroxide 173 166 143 135 129 di-t~amy1 pæroxide167 150 137 129 123 ~1 12 di-cumyl paroxld~161 154 131 123 117 13 ~ 2, 5-d~th~1~2, 5 -164 157 134 126 120 14 di(t-bu~ylperoxy~hexane ' ;~ 5 P~BQ~s 16 1, 1 - di-tannylperoxy- 134 12a 106 9g 93 17 cycloh2xane ,~
8~ D5~ ~YI_L~ 5 d~ thylhexylp~roxy- 85 79 60 54 49 20 :di~arbo~a~

: Z~2~
d~dec oyl peroxid~ 102 96 76 69 64 24 d-~e~zoyl peroxids114 108 86 78 73 PLI~OEY_e~E~
26 t-buty1 ~eroctoat-115 ?~9 90 82 77 : 27 2~8 t-butyl perbenzoate 1~2 144 119 110 104 AZO~CO~POUNDS

::: :

: ~2 W~94/02~71 PCT/USg3/06gl~

01 ~h~ amount o initiator to employ depends to a large ext~nt 02 on the particular initiator chosen, the olefin used and the 03 reaction conditions. The initiator should generally be 0~ ~oluble in the reaction ~edium. The usual concen~rations of OS initiator are between 0.001:1 and 0.4:1 moles of initiator 06 per ~ol~ of polyolefin reactant, with preferred amounts 07 betwe~n 0.005:1 and 0.20:1.

09 In carrying out the process of the invention, a single free ~0 radical initiator or a mixture of free radical initiators 11 may be employed. For examplP, it may be desirable to add an 12 initiator having a low decomposition te~perature a~ the 13 mixture is warming to reaction temperature, and then add an initia~or: ha~ing a higher decomposition temperature as the mixture reaches high~r reaction temperatures.
lS Alt~rnatively, a combination of initiators could both be 17 added prior to hea~ing and reaction. In this case, an initiator having~ a high dec~mposition temperature would 19 ~:initially be inert~ but would later become active as the 20~ ~tempera~ure rose.
2~
22 ~h~ initiator may also be added over time. For exa~ple, if 23 ~ an lnitiator is chosen with a short h~lf-life, e.g., 5-20 24 minutes, at the reaction temperatur~, then the initiator may be added over a period of time so that an adequate 2~ Goncentration of free radicals will be available throughout 27 the rea~tion period to give impro~ed 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) 33 peroxide initiator, this temperature i5 typic`ally about 34 160C or higher.

WO g4/02~71 P~r/vss3/~ssls ,~ ~ .

~1 A~ us~d ~er~in, the term "multiple adduction~l refers to the 02 alkenyl succinic a~hydride re~ction product of maleic 03 anhydride and polyolefin, wherein more than one molecule of 04 malaic anhydride is bonded to one molecule of polyolePin.

06 The av~rage level of multiple adduction can be calculated 07 from the saponification number (mg KOH per gram of sample) 08 and the active content of the alkenyl ~uccinic anhydride 09 product and the molecular weight of the tarting polyolefin.
~ By "average level of multiple adduction" i~ meant the 11 average number o~ ~uccinic groups per polyolefin group in ~2 the alkenyl succinic anhydride product. For example, an 13 average multiple adduction level of 1.0 indicates an average of o~e SU~GiniC grGup per polyolein group in the alkenyl succinic anhydride product. Likewise~ an average multiple 16 addu~tion level of 1.35 indicates an average o~
17 ~.35 succinic groups per polyolefin group in the alkenyl succinic anhydride product, and ~o forth.

20 :~The active~ co~tent of the alXenyl succinic a~hydr~de 21 product is measured in terms of the actives fraction, 22 wherein an actives fraction of 1.0 is e~uivalent to 23 100 percent actives. Accordingly, an activ~s ~raction of 24 0.5 would correspond to 50 percent actives.

26 The average level of multiple adduction for the alkenyl 2~ succinic anhydride product of maleic anhydride and 28 polyolefin can be calculated in accordance wi ~ the 29 following equation:

31 Ayerage Level of = Mpo x P
3~ Multiple Adduction (C x ~) - (M~A x P) ~ W~94/02571 PCr/VS53/06915 Ol wherein P = ~aponif ic:ation number o~ the alkenyl 0~ su¢cinic: anhydride ample (mg ~OH/g~

0~ A = ac:tives fraction of the alkenyl fiU ~ inic S anhydride sample Q7 ~pO = number average molecular weight of the starting polyolefin o~
~o PqMA mol~3cular weight of maleic anhydride C = c:onv~rsion factor = ll2220 (for a : c:onversi~n of gram-mole~ of alkenyl a ~ .
suc:cinic anhydrid~ per gram o~ sample to 15: ~nilligrams of KOH per gram of sampl~

17~ Th@ ~ponif ic:ation nu~9: er, P, can be measured using known a~; procedures, for examp1e, as d~scr~bed i~ ~S~q D94.
19 ;
2~ ~ ~ The actives ~ractiorl o~ the alkenyl ~uc~:inic anhydrid~ can 21 be determined frora the percent of unreacted polyolefin 22 ~ acc~rding to the following procedure~ A SO 0 gram sample of 23 the reac:tion product o~ maleic a~ydride and polyo}ef in is 2~ dissoIv~l in hexane,:pl~ced in a column of 80.0 grams of 2s ~;ilica ~el (Davi~il 62, a l40 angstro~ pore siæe ~ilica 26 gel), and ~lu~d with 1 liter of hexane. The psrc:ent 27 : unreacted po}yolef in i~s determined by removing the hexane 8 solvPn under vacuum frs7m the eluent and weighing the 2 9 residue . Percent unreacted polyolef in i calclllated 30 ~c ording to the following formula:

~3 WO 94/0~571 PCr/US93~06915 ~

9~ ~

0~ Net ~eight of 02 Percent V~eac:ted Polyolef in = S~ple Weight 0~
05 The weight percent actives f or the alkenyl ~i;uccinic 0~; ~nhydride produe:t is calculated from the percent unreacted 07 polyole~in using the f ormula:
o~
We ght Percent = 100 - Percent Unreacted Polyolef 1~ .
12 Thla~ actives fraction of the alkenyl ~uccinic anhydride i~;
13 ~ :then calculated a~; follows:

~ Actives Frac~iorl = Welah~ Per ent Ac:tives : ~ :
16 : :~
Th~ percent conversion of polyole~in i~ aalculated from the we~ght percent~ active~ as follows:

~21 ~ 6 x Percer~ actives (~ tMMA x MADI)] ) 22 ~on~e2~sion ~
2~3~ rwt-%:X~ r~-wto%l 4 Lac:tives lMpo ~ lMMA x MADD]JJ ~actives 26 wherein Mpo = nwnber aver~ge molecu~ ar wei~t of the 7 ~tarting polyolef in .

~A = molecular weight of maleic anhydride.
31 MADD -- average level of multiple adduction.

3~

~ ~094/~2571 PCT/US93/0~91~

~1 19~12 ~ It is, o~ course, understood that alkenyl sucGinic anhydrid~
Q2 products having high average le~els of multiple addurtion, 03 as prepare~ ~y the process of the prese~t inven~ion, can 0~ al~o b~ ble~ded with other alkenyl ~uccinic anhydrid~
05 having ~ lower a~erage level of multiple adduction, for 06 ~x~mple, a lev~l of arou~d l.0, t9 provide an alkenyl 07 succinic anhy ~ ide product ~aving an inkermediate average 08 l~vel of multiple adduction.

10 The following examples are offered to specifically ll ill~trate this invention. These examples and illustrations 12 ar~ not be construed in any way as li~iting the scope of 13 ~hi~ invention.

E~M~LEs 17 : ExamPle l Step~a~
Q :2648 grams t2.04 moles) of polyisobutene having a number B~ a~erag~ol~cular weight of 1300 and a me~hy~inyl~dene 2l i~omer conten~of:about 6 p~rceng was oharged to a reactor, 22 ~heat~d to 1509C and stirred at 60 rpm with a mechanical 23 ~stirrer. TO this was added a mixture of 29~8 gram~
2~: ~:0.204 mole) of di-t-butylperoxide, 318 ~rams of 100 neutral dilue~t oil and a total of 399.4 grams (4~08 mol~s) of 26 malei a~hydr~de ov~r a four hour period. Then the reaction 27 was held at:l50C-for an additional one hour. The resulting 28 polyisobutenyl~succinic anhydride product had a 29 saponificakion number of 63.8 mg KOH/gram sample, 45 weight perce~t actives, and an average o~ about 1.87 succinic 31: groups per polyisobutenyl group. The conversion of 32 polyisobutene was about 41.8 percent. The half-life of the ~3 di-t-butylperoxide free radical initiator at the reaction 3q temperatur~ of 150C is about 1 hour.

W094/02571 PC~/US93/06915f ?.~39~

01 ~, 02 4000 grams of the polyisobutenyl succinic anhydride product 03 obtained from two runs of ~he procedure d~cribed in 04 step ta), ~ontaining 55 weight pPrcent unreacted 05 polyi~obutene, wa~ pla~ed i~ a reactor. The temperature was 06 rai~d tQ 232C and to this was added 867 gram~ (8.85 grams) 07 of maleic anhydride over a period of 4.5 hours. The 08 re~ction pre~sure was maintained at 24 psia (9.3 psig). The 09 reaction was held at 232C for an additional 0.5 hour. Then the exeess ~aleic anhydride was removed in vacuo and the 11 product was filtered at 200C. The resulting polyiso~utenyl 2 succinic anhydride product had a saponification number of 3~ 85.~ mg KOH/gram of sample, 71.4 weight percent actives, and an averag~ of about 1.56 succiniG groups per polyisobutenyl 15 ~:group. ~he conversion of polyisobutene wa~ about 69.1 16 perc~nt. According, ~he total conversion after carrying out 7 ~tep (~) was 27.3 perce~tage points higher than the 18 ~ aonversion in Step (a~.
g: ~ :
Example_2 (ComearatiyeL

22 This example demonstrates that a one ~tep~ free radical 23 initiated process ~orresponding to step (a) o~ the instant 24 i ~ ention r~sults in a poorer yield of the desired alkenyl succinic a~hydride product than the unique two~step process 26 of t~ present invention.

28 61,900 grams (47.6 moles~ of polyisobutene ha~ing a number 29 average molecular weight of 1300 and a methylvinylidene isomer contant of about 6 percent was charged to a reactor 3~ and heated to 150C. To this was added over a twelve-hour 32 period a mixture of 695.2 grams (4.76 moles) of 33 di-t-butylperoxide and a total of 9332.6 grams (95.2 msles) 34 of maleic anhydride. The reaction was then heated to 190C

WO94/02~71 21 I ~ ~1 h PCT/US93/06915 01 ~er a two-hour p~riod in order to decom~o~e the unreacted 02 di~t-butylperoxide. Any unreacted ~aleic anhydride was then 03 r~oved in vacuo tO.18 psia) at 190C for one houx. The 0~ product was ~iltered to gi~e ~ polyisobut~nyl su~cinic 05 anhydride having ~ ~aponifieation numb~r of 94.5 mg KOH/gram 06 of ~a~ple, 65.4 weigh~ percent active~, and an averag~ of 07 a~out 1.92 uccinic groups per polyisobu~enyl group. The ~8 con~er~ion of polyi~sbutene was about 62.3 percent.

~xam~le 3 (Com~arative~

12 This exa~ple de~ons~rates that a one-step thermal reaction 13 o~ polyiso~ut@ne and maleic a~hydride does not provide an : 14 alkenyl ~uccinic anhydrid~ having a multiple adduction l~vel ~f greater tha~ 1~2 ~uccinic groups per alkenyl group.

17 3000 gra~ (2.31 moles) of polyisobutene having ~ number ~erage ~ol~cular waight of 1300 and a methylvinylidene 9 i~o~Qr content of a~out 6 percent was plaGed in a reactor and heated to 232~C. The pressure was maintained at 24 psia : : : :21: ~9.3 psig). To:this was added 1083 grams (11.05 moles~ of ; 22 ~ma~l~ic anhydride. Tbe reaction vessel was h~ated to 232C
23 for a period of 4 hours. Then the exc~ss maleic anhydride 2~ wa~ removed in vaeuo. The product was filtered to g~ve a ::, 25 polisobutenyl 8uccinic anhydrid having a ~aponification : 2~ number of 70.1 mg XOH/gram of sample, 77.2 weight percent 27 actiYes ~ and an average of about 1.09 succinic groups per :~ ~28 polyisobu~enyl group.
2~
: 30

Claims

WHAT IS CLAIMED IS:

1. 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:
(a) 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 100°C to 220°C to provide a mixture of alkenyl succinic anhydride having an average of greater than 1.2 succinic groups per alkenyl group and unreacted polyolefin, wherein the conversion of polyolefin is from about 30 to about 65 percent, and (b) reacting the mixture of alkenyl succinic anhydride and unreacted polyolefin with maleic anhydride at a temperature in the range of about 200°C to 250°C
to thereby provide an alkenyl succinic anhydride having an average of greater than 1.2 succinic groups per alkenyl group, wherein the total conversion of polyolefin is about 5 to 40 percentage points higher than the conversion in step (a).

2. The process according to Claim 1, wherein the alkenyl succinic anhydride produced in either step (a) or step (b) 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 in either step (a) or step (b) 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 in either step (a) or step (b) 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 in step (a) 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 in step (a) is about 1:1 to about 9:1.

13. The process according to Claim 1, wherein about 1 to 9 moles of maleic anhydride will be employed in step (b) per mole of the mixture of alkenyl succinic anhydride and unreacted polyolefin from step (a).