INVENTORS; David Yen-Lung Chen and Stephen A. Lassard

PRIORITY CLAIM TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No. 62/094,710 filed December 19, 2014, the disclosure of which is fully incorporated herein by its reference.

FIELD OF THE INVENTION

[0002] The invention relates to a method and system to quench a polymer slurry from a polymerization reactor to a flash tank with reduced downstream fouling of the equipment.

BACKGROUND OF THE INVENTION

[0003] Industry has generally accepted widespread use of a slurry polymerization process to produce butyl rubber in a diluent, commonly methyl chloride. Typically, the slurry polymerization of isoolefins such as isobutylene with any comonomers uses methyl chloride at low temperatures, generally lower than -90°C, as a diluent for a reaction mixture. Methyl chloride is used for a variety of reasons, including that it dissolves monomers and aluminum chloride catalysts but not polymer product. Methyl chloride also has suitable freezing and boiling points to permit, respectively, low temperature polymerization and effective separation from the polymer and unreacted monomers.

[0004] Commercial reactors typically used to make butyl rubber slurries are well mixed vessels of greater than 10 to 30 liters in volume with a high circulation rate provided by pump impellers. The polymerization and the pumps both generate heat, which is removed by heat exchangers to keep the slurries cold. The slurries are circulated through heat exchanger tubes. The product slurry is generally transferred from the butyl reactor to a quench drum or tank where it is mixed with a quench fluid, usually steam and/or hot water, to terminate any further polymerization and remove the diluent.

[0005] The polymer usually has a lower density than the diluent, and a reactor overflow line is used to transfer the polymer slurry from the reactor. The overflow transfer line transfers the chilled polymer slurry to a flash tank that is generally operated at a relatively warmer temperature ranging from the boiling point of the diluent up to the boiling point of water, e.g., from +40° to 100°C.

[0006] Reactor overflow transfer lines have a tendency to plug during polymer production cycles when using methyl chloride diluent. In methyl chloride diluent, the polymer particles tend to contain dissolved diluent and can be soft with a tendency for particles to stick together and to reactor surfaces, i.e., the particles are "sticky" and thought to cause transfer line plugging by agglomeration of particles and adhesion to the surfaces in the transfer line. Typically with methyl chloride diluent, the transfer line can be unplugged using a steaming practice which is thought to evaporate a thin film of methyl chloride on the internal surfaces of the line and/or to expel methyl chloride from the polymer particles. Elaborate steam sparging lines and condensate collection systems (not shown), including steam jacketing of the transfer line, have been devised for unplugging or preventing plugging of the transfer lines. The plug can often be released in this manner and pressured out of the transfer line, due to the soft nature of the rubber particles when using methyl chloride.

[0007] The utilization of hydroflourocarbons (HFCs) in diluents or blends of diluents has created new polymerization systems that reduce particle agglomeration and fouling in the reactor without having to compromise process parameters, conditions, or components and/or without sacrificing productivity/throughput and/or the ability to produce high molecular weight polymers. The use of HFCs is described in WO2004/058827. However, surprisingly even when using an HFC, the transfer line also has a tendency to plug and, unlike methyl chloride slurries, can not be easily cleared with the application of steam and pressure due to formation of harder plugs of material.

[0008] It is estimated that, regardless of the diluent used, transfer line plugging and downstream fouling of equipment in butyl manufacturing has been a significant source of down time for butyl reactors used in the industry for more than half a century. There is clearly a continued long-felt and unsatisfied need in the art for improvements in butyl manufacturing to reduce plugging and fouling of equipment.

SUMMARY OF THE INVENTION

[0009] According to the present invention, disclosed is a system and method to quench and transport a slurry of polymer and diluent from a reactor wherein the fouling of the downstream equipment is reduced, thereby improving manufacturing capacity and product quality.

[0010] In one aspect, the polymer manufacturing process comprises the following steps: a) contacting in a reactor one or more monomer(s), one or more Lewis acid catalyst, and an optional catalyst initiator, b) reacting the one or more monomer(s) until a polymer of desired molecular weight is formed from the one or more monomer(s), c) removing from the reactor a reactor effluent comprising the formed polymer, unreacted one or more monomer(s), and residual Lewis acid catalyst, d) contacting the reactor effluent with an alcohol, wherein the alcohol has a carbon chain length of four to twelve carbons, d) removing a complex product formed by the contact of the alcohol and the residual Lewis acid catalyst, and e) recovering the polymer of desired molecular weight. The recovered polymer may be further functionalized, for example, by halogenating the polymer.

[0011] In one aspect of the disclosed invention, a diluent is added to the reactor during the step of contacting the one or more monomer(s), the one or more Lewis acid catalyst, and the optional catalyst initiator.

[0012] In any aspect of the disclosed invention, the monomers employed in the polymerization are selected from isoolefins, conjugated dienes, non-conjugated dienes, styrenics, or substituted styrenics.

[0013] In any aspect of the disclosed invention, the alcohol is a straight chain alcohol. In a further aspect, the alcohol has a carbon length of four to eight carbons.

[0014] In any aspect of the invention, the complex formed by the alcohol quench agent and the unreacted, residual catalyst is soluble in a halogenated liquid for at least twenty-four hours, the halogenated liquid being suitable as a diluent for the at least one or more monomers.

[0015] In any aspect of the invention, the complex formed by the alcohol quench agent and the unreacted, residual catalyst is soluble in a hydrocarbon solvent for at least twenty- four hours.

DRAWINGS

[0016] The invention will be described by way of example and with reference to FIG. 1 which is a diagram for manufacturing a halogenated polymer.

DETAILED DESCRIPTION

[0017] The invention relates to a system and method to quench and transport a slurry of polymer and diluent from a reactor, which is producing isoolefin polymers, copolymers, and terpolymers such as polyisobutylene, isobutylene-isoprene polymer, isobutylene-alkylstyrene polymers, isobutylene-isoprene-alkylstyrene polymers, etc., to downstream processing equipment wherein the fouling of the downstream equipment is reduced, thereby improving manufacturing capacity and product quality.

[0018] In a preferred embodiment this invention relates to a process to produce polymers of cationically polymerizable monomer(s) comprising contacting, in a reactor, the monomer(s), a Lewis acid, and an initiator, in the presence of a diluent at a temperature of 0°C or lower, preferably -10°C or lower, preferably -20°C or lower, preferably -30°C or lower, preferably -40°C or lower, preferably -50°C or lower, preferably -60°C or lower, preferably -70°C or lower, preferably -80°C or lower, preferably -90°C or lower, preferably equal to or less than -100°C, preferably from 0°C to the freezing point of the polymerization medium, such as the diluent and monomer mixture and then quenching the reaction by the addition of a quench agent in the polymerization medium.

[0019] For purposes of this invention and the claims thereto, the term "reactor" is any container(s) in which a chemical reaction occurs. Commercial reactors typically used to make these polymers can be well mixed vessels of greater than 10 to 30 liters in volume with a high circulation rate provided by a pump impeller. The polymerization and the pump can both generate heat and, in order to keep the slurry cold, the reaction system can include heat exchangers. An example of such a continuous flow stirred tank reactor ("CFSTR") is found in U.S. 5,417,930, incorporated by reference. In these reactors, slurry can circulate through tubes of a heat exchanger. Cooling can be provided, for example, by boiling ethylene on the shell side. The slurry temperature can be set by the boiling ethylene temperature, the required heat flux and the overall resistance to heat transfer.

[0020] "Slurry" refers to a volume of diluent including polymer that has precipitated from, for example, the diluent, monomers, catalyst system components, e.g., Lewis acid, initiator, modifiers and so on.

[0021] "Diluent" means a diluting or dissolving agent. Diluent can include chemicals that can act as solvents for the catalyst system components, monomers, or other additives. Pure diluent does not generally alter the general nature of the components of a polymerization medium, i.e., the components of the catalyst system, monomers, etc.; however, some limited interactions between the diluent and reactants can occur. Additionally, the term diluent can include mixtures of two or more diluents. Further, halogenated hydrocarbons, such as, for example, methyl chloride and hydrofluorocarbons, are merely non-limiting examples of diluents which can be suitable for use in this invention.

[0022] As used herein, the new numbering scheme for the Periodic Table Groups are used as in Chemical and Engineering News, 63(5), 27, (1985).

[0023] Polymer may be used herein to refer to homopolymers, copolymers, interpolymers, terpolymers, etc. Likewise, a copolymer may refer to a polymer comprising at least two monomers, optionally, with other monomers.

[0024] When a polymer is referred to as comprising a monomer, the monomer is present in the polymer in the polymerized form of the monomer or in the derivative form of the monomer. Likewise, when catalyst components are described as comprising neutral stable forms of the components, it is well understood by one skilled in the art, that the ionic form of the component is the form that reacts with the monomers to produce polymers.

[0025] Isobutylene-based polymer refers to polymers comprising at least 80 mol % repeat units from isobutylene.

[0026] Isoolefin refers to any olefin monomer having two substitutions on the same carbon.

[0027] Multiolefin refers to any monomer having more than one double bond. In a preferred embodiment, the multiolefin is any monomer comprising two conjugated double bonds such as isoprene.

[0028] Elastomer or elastomeric composition, as used herein, refers to any polymer or composition of polymers consistent with the ASTM D1566 definition. The terms may be used interchangeably with the term "rubber(s)," as used herein.

[0029] Alkyl refers to a paraffinic hydrocarbon group which may be derived from an alkane by dropping one or more hydrogens from the formula, such as, for example, a methyl group (CH3), or an ethyl group (CH3CH2), etc.

[0030] Aryl refers to a hydrocarbon group that forms a ring structure characteristic of aromatic compounds such as, for example, benzene, naphthalene, phenanthrene, anthracene, etc., and typically possess alternate double bonding ("unsaturation") within its structure. An aryl group is thus a group derived from an aromatic compound by dropping one or more hydrogens from the formula, such as, for example, phenyl, or C6H5.

[0031] "Quench" or "quenching" refers to the process of rapidly heating and mixing the slurry from the reactor with a quench medium, usually water and/or steam, wherein further polymerization is terminated. For example, the slurry can leave the reactor colder than -90°C and enter the flash tank at 60° C.

Monomers and Polymers

[0032] Monomers which may be polymerized by this system include any hydrocarbon monomer that is polymerizable using this invention. Preferred monomers include one or more of olefins, alpha-olefins, disubstituted olefins, isoolefins, conjugated dienes, non- conjugated dienes, styrenics and/or substituted styrenics and vinyl ethers. The styrenic may be substituted (on the ring) with an alkyl, aryl, halide, or alkoxide group. Preferably, the monomer contains 2 to 20 carbon atoms, more preferably 2 to 9, even more preferably 3 to 9 carbon atoms. Examples of preferred olefins include styrene, para-alkylstyrene, para- methylstyrene, alpha-methyl styrene, divinylbenzene, diisopropenylbenzene, isobutylene, 2- methyl- 1-butene, 3 -methyl- 1-butene, 2-methyl-2-pentene, isoprene, butadiene, 2,3-dimethyl- 1,3 -butadiene, B-pinene, myrcene, 6,6-dimethyl-fulvene, hexadiene, cyclopentadiene, piperylene, methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether and the like. Monomer may also be combinations of two or more monomers. Styrenic block copolymers may also be used as monomers. Preferred block copolymers include copolymers of styrenics, such as styrene, para-methylstyrene, alpha-methylstyrene, and C ₄ to C30 diolefins, such as isoprene, butadiene, and the like. Particularly preferred monomer combinations include 1) isobutylene and para-methyl styrene, 2) isobutylene and isoprene, as well as homopolymers of isobutylene.

[0033] The monomers may be present in the polymerization medium in an amount ranging from 75 wt% to 0.01 wt% in one embodiment, alternatively 60 wt% to 0.1 wt%, alternatively from 40 wt% to 0.2 wt%, alternatively 30 to 0.5 wt%, alternatively 20 wt% to 0.8 wt%, and alternatively 15 wt% to 1 wt% in another embodiment.

[0034] Preferred polymers include homopolymers of any of the monomers listed in this Section. Examples of homopolymers include polyisobutylene, polypara-methylstyrene, polyisoprene, polystyrene, polyalpha-methylstyrene, polyvinyl ethers (such as polymethylvinylether, polyethylvinylether).

[0035] In one embodiment butyl polymers are prepared by reacting with a comonomer mixture, the mixture having at least (1) a C ₄ to Ce isoolefin monomer component such as isobutene with (2) a multiolefin, or conjugated diene monomer component. The isoolefin is in a range from 70 to 99.5 wt% by weight of the total comonomer mixture in one embodiment, 85 to 99.5 wt% in another embodiment. In yet another embodiment the isoolefin is in the range of 92 to 99.5 wt%. The conjugated diene component in one embodiment is present in the comonomer mixture from 30 to 0.5 wt% in one embodiment, and from 15 to 0.5 wt% in another embodiment. In yet another embodiment, from 8 to 0.5 wt% of the comonomer mixture is conjugated diene. The C ₄ to Ce isoolefin may be one or more of isobutene, 2 -methyl- 1 -butene, 3 -methyl- 1 -butene, 2-methyl-2-butene, and 4-methyl- 1-pentene. The multiolefin may be a C ₄ to C14 conjugated diene such as isoprene, butadiene, 2,3-dimethyl- l,3-butadiene, B-pinene, myrcene, 6,6-dimethyl-fulvene, hexadiene, cyclopentadiene and piperylene. One embodiment of the butyl rubber polymer of the invention is obtained by reacting 85 to 99.5 wt% of isobutylene with 15 to 0.5 wt% isoprene, or by reacting 95 to 99.5 wt% isobutylene with 5.0 wt% to 0.5 wt% isoprene in yet another embodiment. [0036] This invention also can be used in the manufacture of terpolymers and tetrapolymers comprising any combination of the monomers listed above. Preferred terpolymers and tetrapolymers include polymers comprising isobutylene, isoprene, and divinylbenzene, polymers comprising isobutylene, para-alkylstyrene (preferably paramethyl styrene) and isoprene, polymers comprising cyclopentadiene, isobutylene, and paraalkyl styrene (preferably paramethyl styrene), polymers of isobutylene cyclopentadiene and isoprene, polymers comprising cyclopentadiene, isobutylene, and methyl cyclopentadiene, polymers comprising isobutylene, paramethylstyrene, and cyclopentadiene.

Lewis Acid

[0037] The Lewis acid (also referred to as the co-initiator or catalyst) may be any Lewis acid based on metals from Group 4, 5, 13, 14, and 15 of the Periodic Table of the Elements, including boron, aluminum, gallium, indium, titanium, zirconium, tin, vanadium, arsenic, antimony, and bismuth. One skilled in the art will recognize that some elements are better suited in the polymerization of the above discussed monomers. In any embodiment, the Lewis acid catalyst is derived from aluminum, boron, or titanium, with aluminum based Lewis acids being most commonly used for the polymerization of isobutylene-based polymers.

[0038] A few illustrative, but not limiting, examples of suitable Lewis acid catalysts useful in cationic polymerization of isobutylene copolymers including: aluminum trichloride, aluminum tribromide, ethylaluminum dichloride, ethylaluminum sesquichloride, diethylaluminum chloride, methylaluminum dichloride, methylaluminum sesquichloride, dimethylaluminum chloride, boron trifluoride, titanium tetrachloride, etc., with ethylaluminum dichloride and ethylaluminum sesquichloride being preferred.

[0039] As one skilled in the art will recognize the aforementioned listing of Lewis acids is not exhaustive and is provided for illustration. For more information regarding Lewis acids in polymerization processes, see, for example, International Application Nos. PCT/US03/40903 and PCT/US03/40340.

Initiator

[0040] Initiators useful in this invention are those initiators which are capable of being complexed in a suitable diluent with the chosen Lewis acid to yield a complex which rapidly reacts with the olefin thereby forming a propagating polymer chain. Illustrative examples include Bronsted acids such as H ₂ 0, HC1, RCOOH (wherein R is an alkyl group), and alkyl halides, such as (CH ₃ ) ₃ CC1, C ₆ H ₅ C(CH ₃ ) ₂ C1 and (2-Chloro-2,4,4-trimethylpentane). More recently, transition metal complexes, such as metallocenes and other such materials that can act as single site catalyst systems, such as when activated with weakly coordinating Lewis acids or Lewis acid salts have been used to initiate isobutylene polymerization.

[0041] In an embodiment, the initiator comprises one or more of a hydrogen halide, a carboxylic acid, a carboxylic acid halide, a sulfonic acid, an alcohol, a phenol, a tertiary alkyl halide, a tertiary aralkyl halide, a tertiary alkyl ester, a tertiary aralkyl ester, a tertiary alkyl ether, a tertiary aralkyl ether, alkyl halide, aryl halide, alkylaryl halide, or arylalkylacid halide.

[0042] As one skilled in the art will recognize the aforementioned listing of initiator(s) is not exhaustive and is provided for illustration. For a more information regarding initiator(s) in polymerization processes, see, for example, International Application Nos. PCT/US03/40903 and PCT/US03/40340.

Diluents / Solvents

[0043] In conventional slurry polymerization of butyl and butyl-type polymer, a diluent is selected for its ready ability to dissolve the monomers and catalyst, and its lack of ability to dissolve the formed polymer. Thus, as the polymer is formed, it precipitates out of the diluent creating a slurry. The most commonly used diluents are organic compounds, with a preference for hydrocarbon fluids.

[0044] Suitable diluents include hydrocarbons, especially hexanes and heptanes, halogenated hydrocarbons, especially chlorinated hydrocarbons and the like. Specific examples include but are not limited: to propane, isobutane, pentane, methycyclopentane, isohexane, 2-methylpentane, 3-methylpentane, 2-methylbutane, 2,2-dimethylbutane, 2,3- dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3- dimethylpentane, 2,4-dimethylpentane, 3,3-dimethyl pentane, 2-methylheptane, 3- ethylhexane, 2,5-dimethylhexane, 2,24,-trimethylpentane, octane, heptane, butane, ethane, methane, nonane, decane, dodecane, undecane, hexane, methyl cyclohexane, cyclopropane, cyclobutane, cyclopentane, methylcyclopentane, 1, 1-dimethylcycopentane, cis 1,2- dimethylcyclopentane, trans- 1 ,2-dimethylcyclopentane, trans- 1 ,3-dimethylcyclopentane, ethylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, ortho-xylene, para-xylene, meta-xylene, and the halogenated versions of all of the above, preferably the chlorinated versions of the above, more preferably fluorinated versions of all of the above. Brominated versions of the above are also useful. Specific examples include methylene chloride, methyl chloride, ethyl chloride, propyl chloride, butyl chloride, chloroform, and the like. [0045] As already noted, there is commercial acceptance of the use of methyl chloride as the diluent in a slurry polymerization process. Typically, the polymerization process extensively uses methyl chloride at low temperatures, generally lower than -90°C, as the diluent for the reaction mixture. Methyl chloride is employed for a variety of reasons, including that it dissolves the monomers and commonly used aluminum chloride catalysts but not the polymer product. Methyl chloride also has suitable freezing and boiling points to permit, respectively, low temperature polymerization and effective separation from the polymer and unreacted monomers. The slurry polymerization process in methyl chloride offers additional advantages in that a polymer concentration of approximately 26% to 37% by volume in the reaction mixture can be achieved, as opposed to the concentration of only about 8% to 12% in solution polymerization. An acceptable relatively low viscosity of the polymerization mass is obtained enabling the heat of polymerization to be removed more effectively by surface heat exchange. Slurry polymerization processes in methyl chloride are used in the production of high molecular weight polyisobutylene and isobutylene-isoprene butyl rubber polymers. Likewise polymerizations of isobutylene and para-methylstyrene are also conducted using methyl chloride.

[0046] Hydrofluorocarbons are useful as diluents in a slurry polymerization of isobutylene based rubber polymers. The hydrofluorocarbons may be used alone or in combination with other hydrofluorocarbons or in combination with other diluents such as the above discussed organic fluids. Hydrofluorocarbons ("HFC's" or "HFC") are defined for the purpose of this invention to be saturated or unsaturated compounds consisting essentially of hydrogen, carbon and fluorine, provided that at least one carbon, at least one hydrogen, and at least one fluorine are present.

[0047] In certain embodiments, the diluent comprises hydrofluorocarbons represented by the formula: C _x H _y F _z wherein x is an integer from 1 to 30, alternatively from 1 to 20, alternatively from 1 to 10, alternatively from 1 to 6, alternatively from 2 to 20, alternatively from 3 to 10, alternatively from 3 to 6, most preferably from 1 to 3, wherein y and z are integers and at least one.

[0048] In any embodiment, the diluent comprises non-perfluorinated compounds or the diluent is a non-perfluorinated diluent. Perfluorinated compounds being those compounds consisting of carbon and fluorine. However, in another embodiment, when the diluent comprises a blend, the blend may comprise perfluorinated compound, preferably, the catalyst, monomer, and diluent are present in a single phase or the aforementioned components are miscible with the diluent as described in further detail below. A diluent blend may also comprise chlorofluorocarbons (CFC's), or those compounds consisting of chlorine, fluorine, and carbon.

[0049] In another embodiment, when higher weight average molecular weights (Mw) (typically greater than 10,000 Mw, preferably more than 50,000 Mw, more preferably more than 100,000 Mw) are desired, suitable diluents include hydrofluorocarbons with a dielectric constant of greater than 10 at -85 °C, preferably greater than 15, more preferably greater than 20, more preferably greater than 25, more preferably 40 or more. In embodiments where lower molecular weights (typically lower than 10,000 Mw, preferably less than 5,000 Mw, more preferably less than 3,000 Mw) are desired the dielectric constant may be less than 10, or by adding larger amounts of initiator or transfer agent when the dielectric constant is above 10. The dielectric constant of the diluent eD is determined from measurements of the capacitance of a parallel-plate capacitor immersed in the diluent [measured value CD], in a reference fluid of known dielectric constant eR [measured value CR], and in air (εΑ=1) [measured value CA]. In each case the measured capacitance CM is given by CM= eCC+CS, where ε is the dielectric constant of the fluid in which the capacitor is immersed, CC is the cell capacitance, and CS is the stray capacitance. From these measurements eD is given by the formula eD=((CD-CA) eR + (CR-CD))/(CR-CA). Alternatively, a purpose-built instrument such as the Brookhaven Instrument Corporation BIC-870 may be used to measure dielectric constant of diluents directly. A comparison of the dielectric constants (ε) of a few selected diluents at -85 °C is provided below.

Table 1

[0050] In other embodiments, one of any of the above diluents may be used in combination with another diluent or mixtures of diluents. In another embodiment, the diluent or diluent mixture is selected based upon its solubility in the polymer. Certain diluents are soluble in the polymer. Preferred diluents have little to no solubility in the polymer. Solubility in the polymer is measured by forming the polymer into a film of thickness between 50 and 100 microns, then soaking it in diluent (enough to cover the film) for 4 hours at -75°C. The film is removed from the diluent, exposed to room temperature for 90 seconds to evaporate excess diluent from the surface of the film, and weighed. The mass uptake is defined as the percentage increase in the film weight after soaking. The diluent or diluent mixture is chosen so the polymer has a mass uptake of less than 4 wt%, preferably less than 3 wt%, preferably less than 2 wt%, preferably less than 1 wt%, more preferably less than 0.5 wt%.

[0051] The diluent or diluent mixture may also be selected such that the difference between the measured glass transition temperature Tg of the polymer with less than 0.1 wt% of any diluent, unreacted monomers and additives is within 15°C of the Tg of the polymer measured after it has been formed into a film of thickness between 50 and 100 microns, that has been soaked in diluent (enough to cover the film) for 4 hours at -75°C. The glass transition temperature is determined by differential scanning calorimetry (DSC). Techniques are well described in the literature, for example, B. Wunderlich, "The Nature of the Glass Transition and its Determination by Thermal Analysis," in Assignment of the Glass Transition, ASTM STP 1249, R. J. Seyler, Ed., American Society for Testing and Materials, Philadelphia, 1994, pp. 17-31. The sample is prepared as described above, sealed immediately after soaking into a DSC sample pan, and maintained at below -80°C until immediately before the DSC measurement. Preferably the Tg values are within 12°C of each other, preferably within 11°C of each other, preferably within 10°C of each other, preferably within 9°C of each other, preferably within 8°C of each other, preferably within 7°C of each other, preferably within 6°C of each other, preferably within 5°C of each other, preferably within 4°C of each other, preferably within 3°C of each other, preferably within 2°C of each other, preferably within 1°C of each other.

[0052] Solution processes for producing isobutylene-based polymers or butyl polymers are also commercially practiced. In the solution process, the monomers, catalysts, and the resulting polymer are all dissolved in an inert hydrocarbon solvent. Suitable inert hydrocarbon solvents for a solution polymerization process include inert hydrocarbons such as benzene, toluene, hexane, heptane, cyclohexane and others. Polymerization Process

[0053] The polymer may be produced in continuous or batch processes. The reactor may be a plug flow reactor, a continuous stirred tank reactor, a boiling pool reactor, and/or other reactors which facilitate flow and interaction of the monomers and catalyst. In the art, reactors useful for producing isobutylene based or butyl polymers at temperatures less than 0°C are referenced as "butyl reactors." Illustrative examples include any reactor selected from the group consisting of a continuous flow stirred tank reactor, a plug flow reactor, a moving belt or drum reactor, a jet or nozzle reactor, a tubular reactor, and an autorefrigerated boiling-pool reactor.

[0054] In any embodiment, the polymer may be obtained in a slurry polymerization process or a solution polymerization process. In either the slurry or solvent process, the polymerization is carried out when the catalyst, monomer, and diluent are present in a single phase. Preferably, the polymerization is carried-out in a continuous polymerization process in which the catalyst and monomer(s) are present in a single phase by being dissolved in the organic liquid diluent or inert hydrocarbon solvent. In slurry polymerization, the monomers, catalyst(s), and initiator(s) are all miscible in the diluent or diluent mixture, i.e., constitute a single phase, while the polymer precipitates from the diluent with good separation from the diluent. Desirably, reduced or no polymer "swelling" is exhibited as indicated by little or no Tg suppression of the polymer and/or little or no diluent mass uptake. For solution polymerization, the polymer stays dissolved in the inert hydrocarbon solvent.

[0055] The order of contacting the monomer feed-stream, catalyst, and, optional, initiator, and diluent or solvent may vary depending on the manufacturer's preference. For more information regarding polymerization processes, see, for example, International Application Nos. PCT/US03/40903 and PCT/US03/40340.

[0056] Figure 1 illustrates a simplified flow diagram for halogenated polymers; the full diagram is for a slurry polymerization process and the steps within the dashed portion are absent when the polymer is manufactured using in a solution polymerization process. While the flow chart specifically references halogen functionalization of the polymer, the present invention is useful whenever it is desired to quench any remaining catalysts present in the reactor effluent that could negatively affect further processing or reactions with the polymer.

[0057] Monomer feeds are cooled to below about -0 °C and fed to the polymerization reactor. Catalyst feed is prepared and also fed to the reactor. These feed streams are not shown in the flow diagram but would be readily appreciated by those in the art. Within the reactor, polymerization takes place at a temperature normally maintained in a range from about -0°C to about -98°C by a cooling system. Typically, the reactor is a continuous flow stirred tank-type reactor. The reactor is generally fitted with an efficient agitation means, such as a turbo-mixer or impeller(s), an external cooling jacket and/or internal cooling tubes and/or coils, or other means of removing the heat of polymerization to maintain the desired reaction temperature, inlet means (such as inlet pipes) for monomers, diluents and catalysts (combined or separately), temperature sensing means, and an effluent overflow or outflow pipe which withdraws polymer, diluent and unreacted monomers among other things. Preferably, the reactor is purged of air and moisture. One skilled in the art will recognize proper assembly and operation.

[0058] Material, including the polymer produced during polymerization, exits the reactor as an effluent stream. As the reactor effluent is heated from below -0°C to temperatures in the range of 25° to 75°C, the unreacted catalyst may form undesirable species that will interfere with further functionalization, such as the illustrated halogenation, of the polymer. Thus, it is preferable to quench the effluent stream and terminate all reactive ability of the catalyst prior to any significant heating of the effluent stream. In the slurry polymerization process, this occurs prior to vaporing the diluent and dissolving the polymer into a solvent. In the solution polymerization process, the reactor effluent is desirably quenched prior to significant heating of the stream and prior to halogenation (i.e., the removal of the step in the dotted box of Figure 1).

[0059] Halogenation of the dissolved polymer is carried out by adding halogen liquid or vapor to the polymer solution. Halogenation of isobutylene copolymers is also described in U.S. 5,670,582. Following functionalization, including the noted halogenation, of the polymer, the stream is neutralized with a caustic wash, followed by removal of the solvent via steam, thereby flashing off the solvent. The wet rubber slurry is then dried by a manufacturer's preferred method. The dried polymer is generally obtained in a crumb form that may be baled or packaged.

[0060] It is nearly always desirable to quench the catalyst in the reactor effluent stream in order to prevent continued polymerization, with the concommitant production of low molecular weight ends and/or to prevent degradation and cross-linking reactions from occurring as the effluent is warmed. With the aluminum-based catalysts usually employed in making the copolymers discussed herein, and with the high catalyst efficiencies achieved, a separate catalyst residue removal step is not generally required, but much of this residue is extracted into the water phase in conjunction with conventional water-based finishing processes anyway.

[0061] As discussed above, if the catalyst is not properly quenched, reactions may continue after the polymer slurry has exited the reactor and as the slurry progresses through the process post-reactor. These post-reactor reactions may interfere with halogenation, create fouling in equipment, and undesirably impact polymer molecular weight.

[0062] As the polymerization diluent is replaced with a hydrocarbon solvent for slurry polymerization processes or as the solvent based effluent for solution polymerization processes, the quench agent added to the effluent should be capable of forming a solvent soluble complex to preclude precipitation of the quenching agent from the solution. Conventional quench agents have been methanol or triethylene glycol (TEG). However, these known quench agents form complexes that are not soluble in the solvent, and these complexes precipitate out during movement of the material and can create solid blockages in downstream piping, heat exchanges, and drying towers.

[0063] It has been determined that an ideal quenching agent will have the following characteristics: 1) reduced ability or inability to forming a three-dimensional complex with the Lewis acid catalyst; 2) reasonable solubility in the polymerization diluent; 3) low freezing point to prevent freezing of quench agent when contacting the reactor exiting slurry stream; 4) ability to form a complex with the Lewis acid wherein the complex is soluble in the hydrocarbon solvent used to replace the diluent from the reactor exiting slurry stream; and 5) no to minimal effect on product quality. The present invention is directed to reduce fouling and blocking of equipment due to the selection of the quench agent.

Experiments

[0064] Multiple compounds were tested as possible quench agents, including already commercially utilized methanol and TEG. The compounds were mixed with a) methylene chloride, used as the exemplary polymerization diluent and to simulate methyl chloride, and b) hexane, used as the exemplary solvent. Ethylaluminumdichoride (EADC) was used as the exemplary catalyst. The resulting mixtures were analyzed; the results are set forth below.

Table 2 Density 0.791 0.864 0.810 0.811 0.814 0.830 1.126

Formula weight 32.04 66.14 74.12 88.15 102.18 130.23 150.17 (gm/mole)

Vapor Pressure 97 @ 20 33 @ 20 5 @ 20 °C 1.5 @ 20 170 @ 28 @ 100 <0.01 @ (mm Hg) °C °C °C 100 °C °C 20 °C

Soluble in Yes; clear white Yes; clear Yes; clear Yes; clear Yes; clear Yes; clear methylene solution aggregate solution solution solution solution solution chloride after 24

hours

Complex white white Yes, clear Yes, clear Yes, clear Yes, clear Not solubility in aggregate aggregate solution solution solution solution soluble hexane formed formed

[0065] For the fluids evidencing a lack of solubility for the EADC-quench agent complex in hexane, it is expected that the fluid will also not be suitable, or preferable, when using aluminum trichloride based catalysts as aluminum trichloride is less soluble in hexane than EADC and any resulting complex formed with the AICI ₃ by the quench agent would also be less soluble in a hydrocarbon solvent. Comparable results of a lack of solubility would also be expected when using other aluminum chloride based catalysts.

[0066] The data suggest higher alcohols with hydrocarbon chain length of at least four carbons should form hexane-soluble complexes with aluminum chloride based catalysts and can be used as a quench agent with no or significantly reduced fouling downstream of the reactor. Alcohols with chain lengths greater than 12 may crystalize at low temperatures, comparable to a wax, thus reducing any quenching efficiency.

[0067] In accordance with the present invention, primary C ₄ to Cs alcohols, linear or branched, are selected as providing the desired characteristics for a quench agent.

Specific Embodiments

[0068] The invention, accordingly, provides the following embodiments:

Paragraph A: A polymer manufacturing process comprising the steps of i) contacting in a reactor one or more monomer(s), one or more Lewis acid catalyst, and an optional catalyst initiator, ii) reacting the one or more monomer(s) until a polymer of desired molecular weight is formed from the one or more monomer(s), iii) removing from the reactor a reactor effluent comprising the formed polymer, unreacted one or more monomer(s), and residual Lewis acid catalyst, iv) contacting the reactor effluent with an alcohol wherein the alcohol has a carbon chain length of four to twelve carbons, v) removing a complex product formed by the contact of the alcohol and the residual Lewis acid catalyst, and vi) recovering the polymer of desired molecular weight;

Paragraph B: The process of Paragraph A, wherein a diluent is added to the reactor during the step of contacting the one or more monomer(s), the one or more Lewis acid catalyst, and the optional catalyst initiator;

Paragraph C: The process of Paragraph B, wherein the diluent is selected from a hydrocarbon, halogenated hydrocarbon, or hydrofluorocarbons;

Paragraph D: The process of any one of Paragraphs A to C, wherein the one or more monomer(s) is selected from isoolefins, conjugated dienes, non-conjugated dienes, styrenics, or substituted styrenics;

Paragraph E: The process of any one or any combination of Paragraphs A to D, wherein the recovered polymer is an isobutylene based polymer further comprising either isoprene derived units or alkylstyrene derived units;

Paragraph F: The process of any one or any combination of Paragraphs A to E, wherein the Lewis acid catalyst is a Group 13 metal compound;

Paragraph G: The process of any one or any combination of Paragraphs A to F, wherein the Lewis acid catalyst is selected from the group consisting of aluminum trichloride, aluminum tribromide, ethylaluminum dichloride, ethylaluminum sesquichloride, diethylaluminum chloride, methylaluminum dichloride, methylaluminum sesquichloride, dimethylaluminum chloride, boron trifluoride, and titanium tetrachloride;

Paragraph H: The process of any one or any combination of Paragraphs A to G, wherein the alcohol is a straight chain alcohol;

Paragraph I: The process of any one or any combination of Paragraphs A to H, wherein the alcohol has a carbon length of four to eight carbons;

Paragraph J: The process of any one or any combination of Paragraphs A to I, wherein the alcohol is a straight chain alcohol of four to eight carbons;

Paragraph K: The process of any one or any combination of Paragraphs A to J, wherein the formed complex is soluble in a halogenated liquid for at least twenty-four hours, the halogenated liquid being suitable as a diluent for the at least one or more monomers;

Paragraph L: The process of any one or any combination of Paragraphs A to K, wherein the step of removing the formed complex comprises removing the formed complex from the reactor effluent by contacting the reactor effluent with a hydrocarbon solvent;

Paragraph M: The process of any one or any combination of Paragraphs A to L, wherein the formed complex is soluble in a hydrocarbon solvent for at least twenty-four hours; Paragraph N: The process of any one or any combination of Paragraphs A to M, comprising the further step of functionalizing the recovered polymer;

Paragraph O: The process of any one or any combination of Paragraphs A to N, wherein the recovered polymer is functionalized by halogenating the polymer;

Paragraph P: The process of any one or any combination of Paragraphs A to O, wherein monomers may be present in the polymerization medium in an amount ranging from 75 wt% to 0.01 wt% in one embodiment, alternatively 60 wt% to 0.1 wt%, alternatively from 40 wt% to 0.2 wt%, alternatively 30 to 0.5 wt%, alternatively 20 wt% to 0.8 wt%, and alternatively 15 wt% to 1 wt% in another embodiment; and

Paragraph Q: The process of any one or any combination of Paragraphs A to P wherein the formed polymer in the reactor effluent is dissolved in the effluent or is a solid precipitate in the effluent.

[0069] All patents and patent applications, test procedures (such as ASTM methods), and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.

[0070] While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.