CA1103692A - Catalyst composition polymerization of isoolefins and multiolefins - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The present invention relates to improved catalyst compositions used in the formation of substantially gel-free copolymers and terpolymers of isobutylene and one or more dienes having an ?n of about less than 500,000, a mole % unsaturation of about 8 to about 45, and a polydispersity value of about 3 to about 30.

Description

11();~i5~2 SUMMARY OF THE INVENTION
The present invention relates to improved catalyst compositions for the formation of substantially gel free copolymers and terpolymers of isobutylene and one or more dienes having an ~n of about less than 500,000, a mole ~
unsaturation of 8 to ~5, and a polydispersity value of 3 to 30, wherein the mixture of isobutylene and diene monomers and a cosolvent are contacted with the catalyst composition at polymerization conditions (-50 to -100 C), wherein the improvement includes a hydrocarbon soluble catalyst composi-tion being formed from the reaction product of (A) a material of the formula:

R AlX
m 3-m wherein m is an integer of from 1 to 3 inclusive, R is the same or different alkyl radical of straight or branched chain structure of frGm 1 to 7 carbons and X is the same or different halogen selected from the group consisting of chlorine and bromine, and (B) a halogen containing material which is Y moles of halogen, halogen acid, and mixed halogen per mole of aluminum compound wherein the halogen is selected from the sroup consisting of chlorine and bromine wherein the molar ratio of the formed catalyst composition to the monomer is critical ~y selectiny at .0001 to 0.001 in order to obtain the desired elastomeric co- and terpolymers. I'he molar ratio of the halogen containing material to the R AlX3 used in forming the catalyst is critically selected at 0.01 A

~5j ,.
,:

i6~;~

to 0.11 and the catalyst composition is soluble in the inert solvent.
Accordingly, it ls an object of the instant inven-tion to provide improved catalyst compositions for the formation of high quality, substantially gel free elastomers of co- and terpolymers of .isobutylene and one or more dienes having an Mn of less than 500,000, a mole ~ unsaturation of 8 to 45, and a polydispersity of 3 to 30. The catalyst is formed from the reaction of RmAlX3 m and a halogen containing material at a molar ratio of the halogen containiny material to the RmAlX3_m of 0.014 to 0.11. The formed catalyst i.s subsequently used at a molar ratio of catalyst to monomer of .0001 to 0.001, wherein improved monomer conversion at higher polymerization temperatures are readily attainable thereby improving the efficiency of ~he process.
The improved catalyst compositions provide a pro-cess whereby it is possible to reduce the ratio of isobutyl-ene to cosolvent thereby resulting in higher monomer ~
conversion, improve~ economics as well as increased cement concentration.
GENERAL DESCRIPTION
The novel improved halogenated organoaluminum catalyst compositions employed in the process of the instant invention are prepared by reacting a material of the formula RmAIX3_~ wherein m is from 1 to 3, R is an alkyI radical of straight or branched chain structure of from 1 to 7 carbons and X lS the same or different halogen selected ~rom the group consisting o~ chlorine and bromine and a halogen con-tainin~ material whlch Y moles of a halogen, halogen acid, : - 3 -:

~ .

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

1103t;~2 or interllalogen per mole of aluminum compound wherein the halogen is selected from the group consisting of chlorine and bromine.
In a more particular embodiment, novel organo-aluminum catalyst compositions are prepared by reacting a material of the formula RAlX2 wherein R is an alkyl radical of straight or branched chain structure of from l to 7 carbons and X is the same or different halogen selected from the group consisting of chlorine and bromine with the halogen containing material which is Y moles of halogen, halogen acid, or interhalogen wherein the halogen is selected from the group consisting of chlorine and bromine.
In an alternative embodiment, the novel catalyst compositions are prepared by mixing materials of the formula R2AlX wherein R is the same or different alkyl radical of straight or branched chain structure of from 1-7 carbons and X is a halogen selected from the group consisting of chlorine and bromine with the halogen containing material which is Y moles of a halogen, halogen acid, or interhalogen per mole ~1()3692 of dialkyl aluminum monohalide wherein the halogen is seleeted from the group eonsisting of chlorine and bromine.
In yet another embodiment, the novel eata-lyst compositions are prepared by mixing, before use, materials of the formula R3Al, wherein R is the same or different alkyl radieal of ,traight or branched chain strueture of from 1-7 earbons with the halogen containing material which is Y moles of halogen, halogen acid, or interhalogen per mole of trialkyl aluminum compound, wherein the halogen is selected from the group eonsisting of chlorine and bromine.
The catalyst preparation is preferably carried out in a solvent, more preferably in a hydrocarbon solvent, most preferably in a paraffinie hydroearbon liquid or mixtures thereof, of from 1 to 10 earbons whieh may be normal branehed or eyclic in strueture.
~he eomponents are preferably diluted in an inert para-ffinic solvent such as butane, isobutane, pentane, iso-pentane, hexane, isomerie 11~)3692 he~anes, cyclohexane, methylcyclohexane or mixtures of paraffinicsolvents are the solvents of choice for the polymerization so as to facilitate mixing and reaction. The catalvst solution con-centrations may range from 0.01 to 50~, preferably 0.2 to 20%, e.g. l~.

The molar ratio of the R Al~ to the monomer is .0001 m 3-m to .001, more preferably .0002 to .0008, and most preferably .0004 to .0006. The molar ratio of halogen containing material to RmAlX3 m is critically selected at 0.014 to O.ll, more prefer-ably at 0.0~5 to 0.055 and most preferably 0.030 to 0.~50. The formation of the catalyst is done prior to contact with the monomers and is preferably at least 60 seconds, more preferably 20, and most preferably 5 thereby ensuring formation of the catalyst prior to contact with the monomers and thus minimizing adverse side reactions of either the halogen containing mzterial.
The reactive catalyst composition thus prepared, exhibitshigher catalytic activity and efficiency than catalysts of the prior art and permits polymerization reactions to be run which yield higher molecular weight polymers and copolymers at higher temperature and/or the inclusion of a greater degree of unsatura--tion in a polymer of either high or low moleculzr weight at temperatures higher than previously possible.
The catalyst compositions of this invention are particu-larly beneficial for homogeneous cationic solution polymerization in hydrocarbon media since they are more reactive than alkyl-aluminum dichlorides or dibromides alone. They also avoid difficulties associated with using hydrocarbon insoluble catalysts such as AlC13 since hydrocarbon slurries of the lztter ~1~3692 frequently cause gelation or fouling, whi'e usin~ polar solvent (i.e. methyl chloride) solutions of the latter catalyst require counteracting the effects of the polar catalyst solvent which is a nonsolvent for the polymer and require diluting the monomer with additional quantities of polymer solvent to maintain homo-geneous polymerization conditions.
The improved catalyst compositions of this invention offer further ~enefits in that they frequently give higher molecu-lar weight polymers and copolymers than the generally available organoaluminum compounds from which they are conveniently and inexpensively prepared. The formation of polymers o higher molecular weights with the novel catalysts of this invention frequently permits operation at warmer polymerization temperatures (-50 to -100 C) while yielding equivalently high mole wt. poly-mers. Since polymer molecular weights generally decrease with increasing temperature in prior art cationic polymerizations, the ability of the catalyst compositions of the instant invention to permit manufacturing of high molecular weight polymers at higher temperature is a marked advance over the prior art.
Since polymerizations are generally quite exothermic and frequently carried out at low temperatures, process limitations relating to solution viscosity, heat transfer rates, maximum solids contents and ultimately production capacity for a given size unit are encountered. Thus, it is heneficial and indus-trially quite valuable if the desired molecular weights can be attained at warmer polymerization temperatures. The present invention features these characteristics and advantages.
The catalysts of this invention are particularly valuable since they not only gi~;e high catalyst efficiencies and high monomer conversion but they also produce higher molecular -~;eight polymers and copoiymers at warmer temperatu~es than con~-entional catalysts.
One group of cationically polYmeri~able monomers suitabl.e for use with the novel improved catalyst compositions of the instant invention are cationically polymerizable unsaturated compounds, especially unsaturated hydrocarbons. Particularly valuable polymers can be prepared from isoolefins of from 4 to 20 carbons, multiolefins of from 5 to 20 carbons, or mixtures there-of to produce homopolymers and copolymers. Examples of such unsaturated hydrocarbons include but are not restricted to iso-butylene, 2-methylbutene, 3-methylbutene-1, 4-methylpentene-1, and ~ -pinene. Multiolefins include but are not limited to butadiene, isoprene, piperylene, 2,3-dimethylbutadiene, cyclo-pentadiene, methyl cyclopentadiene, l,3-cyclohexadiene, dimethyl-fulvene and divinylbenzene.
The catalyst composition of this invention is prepared by diluting in an inert solvent, preferabiy a hydrocarbon solvent, more preferahly a paraffinic hydrocarbon sol~ent, most preferably a paraffinic sol~rent with carbon atoms of 1 to 10, and the catalyst composition which is a reaction product of a hydrocarbyl aluminum halide compound together wi.th a halogen, interhalogen, or halogen acid. The hydrocarbyl aluminum compound has the general formula R AlX3 ~ wherein R is a hydrocarbyl group, preferably an alkyl group ha~ing 1 to 7 carbon atoms, most preferably a C~ to C~ alkyl group and X is a halogen or mi~ture of halogens, preferably chl.orine or bromi.ne, most preferabl~

, , ~103692 chlorine and m is 1-3 inclusive. Preferably, the hydrocarbyl aluminum halide compound has m = 1. ~lost preferably, the hydro-carbyl aluminum halide compound is an alkyl aluminum dichloride.
The quantity of halogen containing materials selected from the group consisting of halogen, halogen acid, or inter-halogen which must be reacted with the hydrocarbyl aluminum compound to obtain the desired catalyst is determined by the value of m in the hydrocarbyl aluminum compound. The molar ratio of the halogen containing material to RAlX2 is .014 to 0.86, more preferably .025 to .055 and most preferably .030 to .050. The molar ratio of halogen containing material to R2AlX is 0.030 to .090, more preferably .040 to .080 and most preferably .050 to .070. The molar ratio of halogen containing material to R3Al is .040 to .12, more preferably .050 to .11, and most preferably .06 to .10.
It is a vital requirement of this invention that said aluminum compound be reacted with said halogen, halogen acid or mixed halogen compound sufficiently prior to introducing the resultant catalyst solution into a polymerization feed containing monomers and cosolvent so as to insure reaction between the catalyst component species to form the catalyst composition.
The cosolvents of the instant invention are selected from the group consisting of cyclic, branched or normal paraffinic hydro-carbons, and mixtures thereof. A preferred cosolvent system is a blend of 75 wt. % of cyclohexane and 25~ wt. ~ hexane. The weight ratio of isobutylene to cosolvent is critically selected at 1 to 10, more preferably at 1.5 to 6 and most preferably at 2 to 5. The critical selection of the ratio of isobutylene to _ g _ . ~ .

cosolvent provides increased monomer ~ conversion at increase~
cement concentration thereby making the process more economical.
The operating temperature of polymeri7ation is -50 to -100 C, more preferably -60 to -95 and most preferably -70 to -90 C.
The operating pressure is 0 to 1000 psig, more preferably 5 to 5~0, and most preferably 15 to 300 and the nominal residence time in a continuous process is 1 to 60 minutes, more preferably 5 to 30 and most preferably 10 to 20.
The components used in forming the catalyst composition 1~ must be premixed, preferably at least 60 seconds more preferably 20 seconds, most preferably 5 seconds before use. The halogen, halogen acid or interhalogen compound may be admixed with a solution of hydrocarbylaluminum dihalide either as neat liquids, gases or preferably in solution in an inert solvent. Solvents such as paraffins are inert to halogens in the absence of free radical initiators and radiation, therefore, said solutions should be protected from light prior to the reaction with alumin-um compound. It is absolutely essential that the components be premixed prior to use.
One embodiment of this invention is the utilization of said improved novel catalyst composition in a process for the preparation of isoolefin homopolymers and copolymers of an isoolefin with multiolefins or mixtures of multiolefins These catalyst compositions have been found to be surprisingly useful for the production of valuable highly unsaturated high molecular weight copolymer of isobutylene with conjugated diolefin(s).
Some of the characteristics of these processes are higher catalyst efficiencies and higher polymer molecular weightsth2n 1103t~92 are reali~ed with ordinary hydrocarbylaluminum dihalides. Many of the novel catalyst compositions of this invention are soluble in hydrocarbons even paraffinic hydrocarbons. They are active in an all hydrocarbon system of monomers and solvents (cosolvents) and frequently give greater monomer conversions, more rapid polymerization, and higher molecular weights. Thus under a wide variety of conditions these catalysts achieve faster reactions and higher molecular wei~hts at warmer temperatures than con-ventional hydrocarbyl aluminum dihalide catalysts. These cat-alyst compositions are particularly valuable for the production of extraordinarily high molecular weight, highly unsaturated copolymers of isobutylene and conjugated diolefins such as cyclopentadiene. As a consequence, highly unsaturated copolymers with number average molecular weights similar to those obtained with hydrocarbyl aluminum dihalide can be produced at substantial-ly warmer polymerization temperatures.
The Mn of the co- or terpolymers formed with the unique and novel process of the instant invention which employs the improved catalyst composition are 30,000 to 500,000, more prefer-ably 40,000 to 400,000, and most preferably 50,000 to 300,000, wherein the mole ~ unsaturation is 8 to 45, more preferably 10 to 40, and most preferably 12 to 40.
A series of copolymers were prepared according to this invention by the following procedure using the unique and novel improved catalyst compositions of the instant invention.
EXAMPLE I
Two identical experiments were conducted in order to illustrate our invention. In the first experiment only methylaluminumdichloride (MADC) and no hydrogen halides were fed into the reaction zone, while in the second experiment anhydrous hydrogen chloride was mixed with the MADC prior to injection into the reaction zone. The contact time of the ~ADC
and HCl was about 5 seconds.
All feed streams were dried before they were injected into a well-stirred stainless steel reactor (reaction zone). The first stream consisted of 78.4 wt. ~ isobutylene, 6.1 wt. %
cyclopentadiene (CPD) and 15.5 wt. % cosolvent (75 wt. g cyclo-hexane and 25 wt. % hexane). The second feed stream consisted of methylaluminumdichloride dissolved in cosolvent (and anhydrous hydrogen chloride in experiment "B").
The first feed stream was chilled to a temperature of -136C prior its continuous introduction into the reactor. The second (catalyst) stream entered the reactor through a separated feed nozzle at ambient temperature. The temperature of the reactor and its contents was maintained constant at -104C by circulating re~rigerant through the reactor jacket. The feed rates of the isobutylene, CPD and cosolvent were adjusted so that a 12-minute nominal residence time was provided in the reactor.
Polymerization occurred only in the reactor. The reactor effluent was contacted with an isopropyl alcohol-ammonia quench stream to deactivate the catalyst.

The process conditions were the following when the reactor achieved steady state.

116)3692 ~1 ~
~ o o ..
~ o~
~ ~, o o -; o o _1 O O
o o~ CO
C~ ~ ~

o o a o o P~ U~
_, '~ o o E~ O ~ c~
U~ C~`

..
e~
Z

O -.
~, e ~ O O
cd ~o ~ ~
l l G

- 15 - 11~369Z

1 ~ The reactor effluent was then ~tabilized with

2 I~GANOX 1010. The ~tabilized polymer solution was then

3 ~team stripped, and the precipitated polymer crumb was

4 dried on a hot mill.
S The obtained process data and the copolymer pro-6 perties are ~hown in Table 2 below.

li~)369;Z
a o ¦
x~

o ~) ~1 ~ ~
~ c~ ~
o ~ ~

u~ n C,~ _, ~
~ o o U) V~
C
U~ O
~1~1 ~o t, ~

o ~ ~ a:~
V o ~ ~ .
~ ~C _1 U -E o .

C
.~ 't:
~;1 Results in Table 2 indicate that the practice of this invention, surprisingly, results in a significant increase in both (isobutylene and CPD) conversions, catalyst efficiency and cement concentration. In addition to the process advantages, it also results in copolymers with much higher molecular weights (Mn 154,000 versus 119,000).
EXAMPLE II
To demonstrate that methylaluminumdichloride (MADC) is preferred, another experiment was conducted following the procedure of Example I. The process conditions and the results of these tests are shown in Tables III and IV below.

, .

~ 20 :

: ~ :

~ ~ - 17 -.. .. . .. , . ..
.
' .', , . ' '' ' ~. " . , . . - . - .

)3692 ,~_ o o ~ U~ o ~ ~ _I
~ ~ ~ C~

U~
E ; o o bC ~ O O
o . I
~n a~
~ o o t~ ~

~1~ o o O o o U~ ~ ~

-~ C 0 oo ~, I 0 ~ ~ V Cr~
~o l l ~J ~ ~ .
C~

C~ ~ ~
X

.~

115)3~;~2 1 The obta~ned process tata and the copolymer pro-2 perties are shown in Table 4 below.

4 Conv.. % CopolYmer Properties Cement 6 Conc. Cat. M/~ ~L @ ~n x 7 Exper. Wt. Z Eff.ISO_CL CPD CPD 127C 10-3 8 A 9.7 73 9 40 31 51 90 9 B 14.0 113 13 56 31 59 83 Results in Table 4 indicate that whlle both alkyl-~ uminumdichlorides are excellent, methylaluminumdichloride 12 is more active than ethylaluminumdichloride.

14 To demonstrate that anhydrous hydrogen bromide also works in the instsnt invention, another experiment was 16 conducted following the procedure of Example I. The process 17 conditions and the results of this test are shown in T~bles 18 5 and 6 below.

Feeds. ~rams/hr ~1 Contact Nom.
22 Time of Reactor Res.
23 HBr and Temp. Time, 24 ADC C Min. IS0-C CPD Cosolv. EADC HBr ~5 sec. -107 18 12,800 1,330 2,560 11.34 .63 26 The obtained process data and the copolymer pro-27 perties are shown in Table 6 below.

29 _ Conv. Z CopolYmer Properties 30 Cement 31 Conc. Catalyst _l 3~ wt. Vb Efficiency IS0-C4 CPD Mole% CPD Ml @ 127C
33 7.7 113 6.5 34 32 53 2 In order to illustrate the gcope of thi~ invention, 3 Table VII below shows a series of copolymers (made with the 4 ~ADC HCl catalyst system according to our invention) with a wide range of unsaturation, molecular weight, and molecular 6 weight distribution (expressed as Q; ~ ~ Mw/Mn).

8 CopolYmer Properties GPC Data MW x 10 3 9 CP~ ~ont.
Example Mole % M~127C Mw Mv Mn Q-Mw/Mn 11 A 11.5 52 1,100 819 147 7.5 12 B 36.5 1121,286 884 140 9.2 13 C 24 55 ~77 518 135 5.0 14 D 31 78 1,108 723 105 10.5 E 35 40 450 312 72 6.2 16 F 36 52 410 315 77 5.3 17 G 37 75 948 650 80 11.9 18 The following terms are herein defined as used in 19 the specification and claims and Bre 8s follows.
1. R - The rate of polymerization in grams per hour.
21 2. Efficiency - The catalyst efficiency was determined in 22 terms of grams of polymer produced per grams of aluminum 23 alkyl dihalide fed.
24 3. ~h Conversion - The percent of isobutylene and separately the percent of diene in~ected into the re~ction vessel, 26 which w~6 converted lnto polymer product, was measured.
27 4. % Unsaturation-Diene Content - The mole % of diene in 28 the polymer w~s measured by refractive index, or NMR.
29 5. Inherent Vlsco6ity - The inherent vi~co~ity of the )3692 polymer product was determined in decalin at 135 C
(AMI 148-023).
6. ML - The Mooney viscosity at 126.7 C was determined using a large ~1 rotor for 8 minutes.
7. Mn - The number average molecular weight was determined by membrane osmometry.
8. Gel Content - The percent of polymer insoluble in toluene at 100 C. One gram of polymer is dissolved in 100 ml of toluene at 100C and filtered through a 200 ln mesh screen. The amount of insoluble polymer retained on the screen is dried and weighed and converted into ~ insoluble polymer. By substantially gel free is meant less than about 2 wt. % of polymer insolubles.
9. Polydispersity~ Q - Ratio of Mw to Mn measured by GPC.

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An improved olefin polymerization catalyst composition comprising a soluble reaction product formed in a solvent by the reaction of:
(A) An aluminum compound of the formula RmA1X3-m wherein m ranges from 1 to 3 inclusive, R is the same or different straight or branched chain alkyl radical having 1 to 7 carbon atoms and X is the same or different halogen selected from the group consisting of chlorine and bromine; and (B) A halogen containing material selected from the group consisting of C12, Br2, HC1, HBr, and a C1-Br interhalogen, the molar ratio of said halogen containing material to said RmA1X3-m being 0.014 to 0.11.

2. The improved catalyst composition of claim 1, wherein RmAlX3-m is R Al.

3. The improved catalyst composition of claim 1, wherein RmA1X3-m is R2A1X.

4. The improved catalyst composition of claim 1, wherein RmA1X3-m is RA1X2.

5. The improved catalyst composition of claim 1, wherein said catalyst composition is formed at least about 5 seconds prior to contacting with said monomers.

6. The improved catalyst composition of claim 1, wherein said solvent is a C1-C10 paraffinic hydrocarbon.

7. The improved catalyst composition of claim 6, wherein a concentration of said catalyst composition in said solvent is .01 to 50 wt. % .

8. The improved catalyst composition of claim 1, wherein said halogen containing material is C12, Br2, HBr or HC1.