Gas-phase polymerization using a homogeneous catalyst or initiator system

Abstract

The present invention relates to a continuous process of monomer polymerization in the gas phase using a homogeneous catalyst system or a homogeneous initiator system in a reactor that includes a device for crushing and mixing aggregated polymers. This process is carried out such that the vapor pressure of each monomer in the reactor is always higher than its partial pressure in the reactor. This condition is maintained in the process by setting appropriate conditions in the reactor. For this purpose, the pressure and temperature in the reactor are adjusted accordingly. Monomers that do not polymerize can be condensed in a condenser and returned to the reactor. Under the dominant conditions in the reactor, the monomers evaporate, providing a cooling effect. This is also true when the monomers are generally introduced into the reactor in liquid form. Furthermore, the condensation of monomers in the condenser reduces the pressure in the reactor.

Description

[Technical Field]

[0001] The present invention relates to a process for the polymerization of monomers in the gas phase. In this process, a homogeneous catalyst system or a homogeneous initiator system is used. [Background Art]

[0002] Polymerization is a chemical reaction in which monomers react to form polymers. Monomers are generally unsaturated organic compounds. The reaction proceeds by cleaving multiple bonds in monomers and forming single bonds between the monomers. Therefore, a polymer is a molecule having a long chain composed of interconnected monomers. A distinction is made between homopolymerization, in which only one type of monomer is converted, and copolymerization, in which two or more different monomers react. The reaction takes place under the influence of a catalyst or after initiation by an initiator. Those skilled in the art are familiar with various catalyst systems and initiator systems, which are selected depending on the monomer to be polymerized. These catalyst systems and initiator systems may be homogeneous or heterogeneous. A homogeneous system does not contain any carrier material.

[0003] Those skilled in the art are familiar with various methods for polymerizing monomers, for example gas phase polymerization, solution polymerization and bulk polymerization (Massepolymerisation).

[0004] Gas-phase polymerization is used on a large industrial scale for the production of polyolefins such as polyethylene and polypropylene. Gas-phase polymerization occurs in gaseous monomers. Catalysts immobilized on carrier materials such as silicon dioxide particles or magnesium chloride particles are used for this purpose. The reaction occurs on and within the particles at the active center of the catalyst. Thus, the catalyst particles become polymer particles, which can be considered microreactors. Therefore, the polymer contains catalyst particles, which can be disadvantageous for certain applications requiring high purity. In this way, homopolymers and copolymers of propylene and ethylene can be obtained. The resulting polymers consist of chains with relatively short branching caused by the structure of the monomers, such as the methyl side chain in polypropylene, or the ethyl side chain when 1-butene is used as the comonomer, or the butyl side chain when 1-hexene is used as the comonomer.

[0005] To produce very pure polyethylene (LDPE) with a high degree of long-chain branching, bulk polymerization is used on an industrial scale, in which ethylene is radically polymerized under very high pressure or supercritical conditions using a suitable initiator. These harsh reaction conditions naturally lead to high energy consumption.

[0006] Known processes must always be carried out in a way that avoids the formation of polymer aggregates as much as possible. The formation of aggregates can severely disrupt the process, usually requiring it to be shut down and the plant's reaction vessels and other components to be cleaned at considerable expense. This involves a great deal of effort and very high costs.

[0007] The risk of aggregation and related problems are reasons why synthetic rubber, an important industrial product, is not manufactured industrially using gas-phase polymerization. Synthetic rubber is highly adhesive, leading to the aggregation of polymer particles.

[0008] The use of gas-phase polymerization for the manufacture of synthetic rubber is described in scientific literature and patent applications. However, the problem of aggregation has not been satisfactorily resolved.

[0009] Generally, fluidized bed reactors or stirred batch reactors are used for gas-phase polymerization to produce synthetic rubber. As mentioned above, it is important to avoid particle aggregation because it leads to operational problems (sheeting, chunking, and reduced fluidity), resulting in overheating, hot spot formation, and ultimately damage to the synthetic rubber product. This results in a decrease in the quality of the synthetic rubber.

[0010] One way to avoid aggregation is to use powders such as silica or carbon black that settle on the surface of the sticky synthetic rubber particles. However, the use of powders introduces other problems.

[0011] Solution polymerization is used industrially to manufacture synthetic rubber. Since polymerization occurs in a solvent, polymer particles are not formed in a separate phase, and therefore no aggregation occurs. The drawback of this process is that it requires the use of large amounts of solvent, which must then be cumbersomely removed from the polymer product. The solvent separated from the polymer product then needs to be purified and returned to the process. Solvent separation and purification are highly energy-intensive and cost-intensive, significantly increasing the CO2 footprint of synthetic rubber production. In addition, the polymer product can be contaminated by the solvent. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] Therefore, there is a great need for a process that can solve known problems. [Means for solving the problem]

[0013] Therefore, the present invention relates to a process (method) for the polymerization of monomers in the gas phase, a) A step of continuously supplying monomers to the reactor, b) A step of contacting monomers in a reactor with a homogeneous catalyst system or a homogeneous initiator system to obtain a polymerizable mixture, c) A step of polymerizing a polymerizable mixture in a reactor to obtain a polymer, d) A step of continuously discharging the polymer from the reactor. Includes, The above monomers are molecules containing unsaturated bonds with carbon atoms. The above reactor includes equipment for crushing and mixing the aggregated polymer. The reactor is connected to a condenser that allows monomers to be collected from the reactor, condensed, and the condensed monomers to be returned to the reactor. This process is directed such that the vapor pressure of each monomer in the reactor is always higher than its partial pressure in the reactor.

[0014] The present invention solves some of the above problems by providing a process that enables monomers to be polymerized in the gas phase using a homogeneous catalyst system or a homogeneous initiator system. Therefore, the polymer does not contain any residue from the carrier material. This process is carried out in a reactor that allows for the breakdown and mixing of any aggregates that may form. Thus, the formation of aggregates does not interfere with the process and does not impair the quality of the product. A condenser can absorb and condense the (gaseous) monomers. The condensed monomers can be returned to the reactor. The process is carried out such that the vapor pressure of each monomer in the reactor, i.e., all monomers in the case of one type of monomer (homopolymerization) or different types of monomers (copolymerization), is always higher than its partial pressure in the reactor, i.e., the monomers are gaseous under these conditions, and these conditions are maintained throughout the process. As a result, the condensed monomers supplied to the reactor via the condenser evaporate in the reactor. Of course, the same applies when liquid monomers are supplied to the reactor according to step a) of the process of the present invention.

[0015] The supply of monomers and discharge of polymers are carried out continuously; that is, the process of the present invention is a continuous process for the polymerization of monomers in the gas phase.

[0016] The condition that the vapor pressure of each monomer in the reactor is always higher than its partial pressure in the reactor is maintained in the process according to the present invention by setting appropriate conditions in the reactor. The pressure and temperature in the reactor are adjusted accordingly.

[0017] It is known to those skilled in the art that polymerization proceeds with exothermic reactions. This heat must be dissipated to prevent overheating. Those skilled in the art are familiar with measures suitable for this purpose.

[0018] In the method according to the present invention, the monomers (that did not polymerize) can be condensed in a condenser and returned to the reactor. Under the dominant conditions in the reactor, the monomers evaporate, providing a cooling effect. Furthermore, the condensation of monomers in the condenser reduces the pressure in the reactor.

[0019] The degree of monomer condensation in the condenser can be controlled by the condenser's cooling capacity. For example, the temperature and / or flow rate of the coolant in the condenser can be adjusted for this purpose. In this way, the pressure and temperature in the reactor can be controlled.

[0020] The pressure inside the reactor can also be adjusted by supplying monomers according to step a) and discharging polymers according to step d) of the method of the present invention.

[0021] In the process according to the present invention, preferably, a liquid monomer is supplied to the reactor in step a). The liquid monomer evaporates under dominant conditions in the reactor, providing a cooling effect. In this way, the temperature in the reactor can be controlled by the rate at which the monomer is supplied to the reactor.

[0022] The temperature inside the reactor can also be adjusted by the rate at which the homogeneous catalyst system or the homogeneous initiator system is introduced, since this rate makes it possible to control the degree of polymerization.

[0023] Compared with solution polymerization, the process of the present invention has the advantage that there is no need to use, separate and purify solvents. This makes the process according to the present invention significantly more energy efficient, resource efficient and cost effective.

[0024] Compared with gas phase polymerization in conventional gas phase reactors (fluidized bed reactors, stirred fluidized beds), the process of the present invention has the advantage that the reactor is less susceptible to agglomeration. In the case of very sticky polymers such as synthetic rubbers, this also eliminates the need for powders to prevent or reduce agglomeration. Furthermore, there is no need to use supported catalysts. Alternatively, conventional homogeneous catalysts known from solution polymerization can be used. This reduces the required labor and materials, thereby lowering the process cost. In addition, the polymer does not contain any residues from the support material.

[0025] According to a preferred embodiment of the process of the present invention, the polymer obtained in step c) is mixed in the reactor by means of an apparatus for crushing and mixing agglomerated polymer, preferably continuously mixed, or crushed and mixed, preferably continuously crushed and mixed, which is similar to a meat grinder.

[0026] Suitable apparatuses for crushing and mixing agglomerated polymer are known to those skilled in the art.

[0027] The apparatus for crushing and mixing the aggregated polymer in the reactor can be based on a single-screw (Einwellen-Apparat) or twin-screw (Zweiwellen-Apparat) reactor. The only important thing is that the polymer obtained in step c) can be crushed and mixed in the reactor using the apparatus for crushing and mixing the aggregated polymer. This means that the shafts and the inner surface of the reactor can be cleaned. In the case of a single-screw reactor, additional counter hooks (Gegenhaken) (scrapers) can be provided in the reactor for this purpose. In the case of a twin-screw reactor, these counter hooks (scrapers) can also be provided, and / or the shafts can clean each other.

[0028] The apparatus for crushing and mixing aggregated polymers used in a reactor according to the method of the present invention should be distinguished from apparatus suitable only for stirring, such as those used in conventional gas-phase reactors (fluidized bed reactors, stirred fluidized beds, see above), the latter of which are not suitable for crushing and mixing aggregated polymers, and are particularly unsuitable for crushing aggregated polymers.

[0029] Rather, as mentioned above, in conventional gas-phase reactors (fluidized bed reactors, stirred fluidized beds, see above), preventing the formation of aggregates is particularly important because aggregates severely disrupt the process, usually requiring the process to be stopped and other parts of the reaction vessel and plant to be cleaned at considerable expense. This involves considerable effort and very high costs. Therefore, in the processes described above, polymers are usually obtained as powder products. The reactor may contain agitators that can help prevent aggregation (see, for example, U.S. Patent No. 4,012,573), but these reactors are not particularly suited to breaking up aggregates that have already formed. Rather, these agitators are mainly used to maintain the fluid state of the powder product in the fluidized bed (see, for example, U.S. Patent Application Publication 2002 / 0198335A1).

[0030] Therefore, the apparatus for crushing and mixing aggregated polymers used in a reactor according to the method of the present invention does not include a stirrer unsuitable for crushing and mixing aggregated polymers.

[0031] Therefore, conventional stirrers known from the prior art, such as those used in conventional gas-phase reactors (fluidized bed reactors, stirred fluidized beds, see above), are not suitable for crushing and mixing polymers aggregated according to the method of the present invention.

[0032] The monomer is typically supplied from the storage tank to the reactor via the metering line according to step a).

[0033] If the monomer contains polymerization stabilizers, these can be separated before polymerization in the usual manner, for example, by re-condensation.

[0034] According to a preferred embodiment of the method of the present invention, a pump transports monomer from a storage tank to a reactor via a metering line. Furthermore, it is preferable to have a device that allows the metering line and the pump to be cooled with chilled water.

[0035] According to a preferred embodiment of the method of the present invention, the cooler also includes a storage tank from which condensed monomers can be collected and supplied to the reactor as needed. The storage tank of the cooler may also be the same as the storage tank described above.

[0036] According to a preferred embodiment of the method of the present invention, the polymer is continuously discharged from the reactor by a screw.

[0037] According to a preferred embodiment of the method of the present invention, the polymer is continuously discharged from the reactor in a non-particulate form.

[0038] According to a preferred embodiment of the method of the present invention, the polymer is degassed after being discharged from the reactor. Degassing is performed under vacuum.

[0039] According to a preferred embodiment of the method of the present invention, polymerization is stopped in a conventional manner, and the polymer is optionally stabilized by adding a stopper and optionally a stabilizer to the discharged polymer. Suitable stoppers and stabilizers are known to those skilled in the art.

[0040] According to a preferred embodiment of the method of the present invention, the reactor is a high-viscosity reactor (Hochviskosreaktor). High-viscosity reactors are known to those skilled in the art. Furthermore, the high-viscosity reactor preferably includes a counter hook (scraper) to prevent the polymer from adhering to the shaft of the high-viscosity reactor.

[0041] In the same preferred embodiment of the method of the present invention, a second high-viscosity reactor is preferably connected to a high-viscosity reactor (first high-viscosity reactor, polymerization reactor) in which polymerization occurs, and the polymer is preferably continuously discharged from the first high-viscosity reactor into the second high-viscosity reactor by a screw. The polymer is preferably continuously discharged from the first high-viscosity reactor in a non-particulate form. It is also preferable to add a stopper and optionally a stabilizer to the polymer in the second high-viscosity reactor. Furthermore, the second high-viscosity reactor preferably includes a device for degassing the polymer. It is also preferable to degas the polymer under vacuum in the second high-viscosity reactor. The finished polymer is preferably carried out of the second high-viscosity reactor through an outlet by a discharge screw.

[0042] The connection between the first high-viscosity reactor and the second high-viscosity reactor can be disconnected for starting purposes. Similarly, the outlet of the second high-viscosity reactor can be closed for starting purposes.

[0043] The first and second high-viscosity reactors can preferably be temperature-controlled via jackets and thermostats. The first high-viscosity reactor also preferably has a counter hook (scraper) to prevent the polymer from adhering to the shaft of the first high-viscosity reactor. The second high-viscosity reactor also preferably has a counter hook (scraper) to prevent the polymer from adhering to the shaft of the second high-viscosity reactor.

[0044] An overhead cooler having a storage tank is preferably attached to the first high-viscosity reactor, which allows condensate to flow into the storage tank and from there into the first high-viscosity reactor.

[0045] According to a preferred embodiment of the method of the present invention, the sum of the masses of the monomer, homogeneous catalyst system or homogeneous initiator system and polymer accounts for at least 90% of the total mass of all substances in the reactor. Furthermore, this sum preferably accounts for at least 95% of the total mass of all substances in the reactor. This sum can account for up to 100% of the total mass of all substances in the reactor.

[0046] The process according to the present invention does not require the addition of a solvent, diluent, or dispersant.

[0047] Accordingly, in a preferred embodiment of the method of the present invention, the total mass of the solvent, diluent and dispersant in the reactor accounts for a maximum of 10% of the total mass of all substances in the reactor, preferably a maximum of 5.0% of the total mass of all substances in the reactor, preferably a further 3.0% of the total mass of all substances in the reactor, and preferably a further 1.0% of the total mass of all substances in the reactor. This total may account for only 0.1% of the total mass of all substances in the reactor, or it may even be 0.0%.

[0048] This invention is generally directed toward a method for polymerizing monomers in the gas phase and is therefore not limited to any particular monomer. A monomer is a molecule containing an unsaturated bond with one, i.e., at least one, carbon atom. Therefore, a suitable monomer must contain at least one polymerizable multiple bond (double or triple bond) with a carbon atom. The selection of a suitable monomer naturally depends on the polymer to be produced.

[0049] Typical monomers include ethylene, olefins such as α-olefins and dienes, acrylic acid esters, methacrylic acid esters, maleic anhydride, nitriles, and styrene.

[0050] The process according to the present invention can be carried out as a homopolymerization or copolymerization using typical monomers.

[0051] According to a preferred embodiment of the process of the present invention, the monomer is a molecule containing an unsaturated carbon-carbon bond (double or triple bond). Furthermore, the monomer is preferably a hydrocarbon, i.e., the monomer consists of carbon and hydrogen atoms and does not contain any other so-called heteroatoms.

[0052] According to a preferred embodiment of the method of the present invention, the monomer is selected from the group consisting of ethylene, α-olefins having 3 to 8 carbon atoms, dienes having 4 to 8 carbon atoms, and mixtures thereof.

[0053] According to a more preferred embodiment of the method of the present invention, the monomer is selected from the group consisting of ethylene, propylene, isobutene, styrene, α-methylstyrene, 4-methylstyrene, ethyl acrylate, methyl methacrylate, ethyl methacrylate, maleic anhydride, acrylonitrile, 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-heptadiene, 2,4-heptadiene, 2-methyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, and mixtures thereof.

[0054] For example, the monomer may consist of a mixture of ethylene, propylene, and diene. The resulting copolymer contains polymer units derived from ethylene, polymer units derived from propylene, and polymer units derived from diene, and is known as ethylene-propylene-diene rubber (EPDM) and is technically related as synthetic rubber.

[0055] According to a more preferred embodiment of the method of the present invention, the monomer consists of at least 50 mol% 1,3-butadiene. Therefore, in this preferred embodiment, the method according to the present invention results in the production of a polymer containing polymer units derived from 1,3-butadiene.

[0056] The remaining monomers may belong to one or more other monomer species, and may result in a copolymer of 1,3-butadiene.

[0057] For example, the monomer may consist of a mixture of 1,3-butadiene and styrene. The resulting copolymer contains polymer units derived from 1,3-butadiene and polymer units derived from styrene, and is known as styrene-butadiene rubber (SBR) and is technically related as a synthetic rubber.

[0058] The monomer is more preferably composed of at least 60 mol% 1,3-butadiene, more preferably at least 70 mol% 1,3-butadiene, more preferably at least 80 mol% 1,3-butadiene, and more preferably at least 90 mol% 1,3-butadiene, based on the total amount of all monomers supplied to the reactor in step a).

[0059] In this preferred embodiment, the method according to the present invention therefore results in the production of a polymer containing polymer units derived from 1,3-butadiene, more preferably comprising at least 50 mol% of polymer units derived from 1,3-butadiene, even more preferably at least 60 mol% of polymer units derived from 1,3-butadiene, more preferably at least 70 mol% of polymer units derived from 1,3-butadiene, more preferably at least 80 mol% of polymer units derived from 1,3-butadiene, and even more preferably at least 90 mol% of polymer units derived from 1,3-butadiene.

[0060] According to a more preferred embodiment of the method of the present invention, the monomer is 1,3-butadiene.

[0061] In this preferred embodiment, the method according to the present invention therefore results in the production of a polymer consisting of polymer units derived from 1,3-butadiene, i.e., a homopolymer of 1,3-butadiene. This homopolymer is known as polybutadiene rubber (BR) and is technically related as a synthetic rubber.

[0062] According to a preferred embodiment of the method of the present invention, the monomer and the homogeneous catalyst system or homogeneous initiator system are continuously supplied to the reactor.

[0063] In step b) of the process of the present invention, the monomer is brought into contact with a homogeneous catalyst system or a homogeneous initiator system in a reactor to obtain a polymerizable mixture.

[0064] The process according to the present invention uses a conventional homogeneous catalyst system or a homogeneous initiator system. These catalysts or initiators are known to those skilled in the art.

[0065] Initiators are used, for example, in radical polymerization. In radical polymerization, peroxides or azo compounds are typically used as initiators. Initiators are also used in anionic polymerization. A typical initiator used in anionic polymerization is butyllithium.

[0066] Typical catalyst or initiator systems are listed below.

[0067] In the following sections, the term "catalytic system (CS)" is used to refer to a typical catalytic or initiator system. (a) Catalytic systems based on coordination catalysts, such as Ziegler-Natta catalysts and metallocene catalysts, that increase the reaction rate by reducing the activation energy without consumption in addition polymerization in which monomers are added to a growing polymer via organometallic active centers, and (b) A catalytic system based on an anionic initiator, such as an alkyllithium initiator, which induces a form of chain growth polymerization or addition polymerization involving the polymerization of monomers having an olefin moiety induced by an active carbanion species consumed by the polymerization process, It includes both.

[0068] The catalyst system (CS) may include a coordination catalyst component (CC) and optionally a co-catalyst component (Co), wherein the coordination catalyst component (CC) is based on transition metals and / or rare earth metals of groups 4 to 10 of the periodic table, and preferably, the coordination catalyst component (CC) is based on titanium, chromium, vanadium, cobalt, nickel, zirconium, neodymium, gadolinium, or a mixture thereof.

[0069] The catalyst system (CS) may include an anionic initiator (AI) and optionally an activator and / or modifier compound (ARC), the anionic initiator (AI) being a monofunctional or polyfunctional organometallic compound, preferably a monofunctional or polyfunctional organoalkali metal compound, preferably a monolithium compound represented by formula RLi, where R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy, and mixtures thereof.

[0070] Catalyst systems (CS) having coordination catalyst components (CC): The catalyst system (CS) may include a coordination catalyst component (CC) and optionally a co-catalyst component (Co).

[0071] The coordination catalyst component (CC) may be a coordination catalyst based on transition metals and / or rare earth metals of groups 4 to 10 of the periodic table. Preferably, the coordination catalyst component (CC) is a coordination catalyst based on titanium, chromium, vanadium, cobalt, nickel, zirconium, neodymium, gadolinium, or mixtures thereof. More preferably, the coordination catalyst component (CC) is a coordination catalyst based on titanium, nickel, neodymium, or mixtures thereof. Even more preferably, the coordination catalyst component (CC) is a coordination catalyst based on neodymium.

[0072] Examples of coordination catalyst components (CCs) include TiCl3, Ti(On-Bu)4, CpTiCl3, Ti(CH2Ph)4, VCl, VCl3, (1,2-dimethylcyclopentadienyl)VCl3, (1,3-dimethylcyclopentadienyl)VCl3, (1,2,3-trimethylcyclopentadienyl)VCl3, (1,2,4-trimethylcyclopentadienyl)VCl3, and (1,2,3,4-tetramethylcyclopentadienyl)VCl3. Examples include CrCl2(1,2-bis(dimethylphosphinoethane)2), Co(acetylacetonate)3, Ni(carboxylate)2, Ni(acetylacetonate)2, NiCl3, Ni(octanoate)2, Nd(1,5-cyclooctadiene), Nd(carboxylate)3, Nd(octanoate)3, Nd(BH4)3, Gd(2,9-dimethyl-1,10-phenanthroline)3, NdV3, and mixtures thereof.

[0073] The coordination catalyst component (CC) is preferably NdV3.

[0074] The cocatalyst component (Co) is used to improve the catalytic activity of the catalyst system (CS). The cocatalyst component (Co) used with the coordination catalyst component (CC) is usually an organometallic compound based on an alkaline earth metal or an organometallic compound based on the boron group of the periodic table, and preferably the cocatalyst component (Co) is a magnesium organometallic compound or an aluminum organometallic compound, with the latter being particularly preferred.

[0075] The co-catalyst component (Co) may be an organoaluminum compound represented by the formula AlRXn3-n, where each R may be the same or different, and is a monovalent organic group bonded to an aluminum atom via a carbon atom; each X may be the same or different, and is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryl oxide group; and n is an integer from 1 to 3. Each R may be, but is not limited to, a hydrocarbon group such as an alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an alkenyl group, a cycloalkenyl group, a substituted cycloalkenyl group, an aryl group, an alkylaryl group, and an alkynyl group. These hydrocarbon groups may, but are not limited to, contain heteroatoms such as a nitrogen atom, an oxygen atom, a boron atom, a silicon atom, a sulfur atom, and a phosphorus atom.

[0076] Examples of co-catalyst components (Co) include, but are not limited to, ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride, dimethylaluminum chloride, trimethylaluminum, triethylaluminum, tri-n-butylaluminum, tri-n-butylaluminum, tri-i-butylaluminum, trihexylaluminum, tri-n-octylaluminum, di-i-butylaluminum hydride, di-sec-butylaluminum hydride, methylaluminum oxane (MAO), hexa-i-butylaluminum oxane (HIBAO), and tetra-i-butylaluminum oxane (TIBAO), as well as mixtures thereof. Preferably, the co-catalyst component (Co) is selected from triethylaluminum, diethylaluminum chloride, tri-i-butylaluminum, ethylaluminum dichloride, di-i-butylaluminum hydride, methylaluminum oxane (MAO), and mixtures thereof.

[0077] The cocatalyst component (Co) may be an organomagnesium compound containing the formula MgRXn2-n, where each R may be the same or different, and is a monovalent organic group bonded to a magnesium atom via a carbon atom; each X may be the same or different, and is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryl oxide group; and n is an integer from 1 to 3. Each R may be, but is not limited to, a hydrocarbon group such as an alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an alkenyl group, a cycloalkenyl group, a substituted cycloalkenyl group, an aryl group, an alkylaryl group, and an alkynyl group. These hydrocarbon groups may, but are not limited to, contain heteroatoms such as a nitrogen atom, an oxygen atom, a boron atom, a silicon atom, a sulfur atom, and a phosphorus atom.

[0078] Examples of cocatalyst components (Co) include, in particular, Examples include dialkylmagnesiums such as diethylmagnesium, di-n-butylmagnesium, di-i-butylmagnesium, di-sec-butylmagnesium, and ethylbutylmagnesium; alkylmagnesium halides such as ethylmagnesium chloride, i-butylmagnesium chloride, sec-butylmagnesium chloride, and n-butylmagnesium chloride; dialkoxymagnesiums such as diethyloxymagnesium, diisopropoxymagnesium, di-n-butoxymagnesium, di-i-butoxymagnesium, di-sec-butoxymagnesium, di-2-ethylhexoxymagnesium, and diphenoxymagnesium; magnesium alkoxyhalides such as methoxymagnesium chloride, ethoxymagnesium chloride, and phenoxymagnesium chloride; and magnesium carboxylates such as magnesium stearate. Preferably, the co-catalyst component (Co) is selected from di-n-butylmagnesium.

[0079] Examples of catalyst systems (CS) containing coordination catalyst components (CC) include TiCl / AlEt33, Ti(OnBu) / AlEt43, Ti(OnBu) / Al-i-Bu43, Ti(OnBu) / AlEtCl42 / MAO, Ti(OnBu)4 / MAO, CpTiCl3 / MAO, Ti(CH2Ph)4 / MAO, VCl / AlEt33, CrCl2(1,2-bis(dimethylphosphinoethane))2 / MAO, Co(acetylacetonate)3 / MAO, Co(acetylacetonate) / AlEt33Cl / H2O, Ni(carboxylate) / AlEt / BF2332, and OEtNi(acetylacetonate). Examples include, but are not limited to, tylacetonate)2 / MAO, NiCl3, Ni(octanoate) / AlEt / BF233, Nd(1,5-cyclooctadiene) / B(CF)653, Nd(carboxylate)3, Nd(octanoate) / AlEt32Cl / Al(i-Bu)3, Nd(BH) / AlEt433, Nd(BH)43(THF) / AlEt33, Nd(BH)43(THF) / BuMg32, Gd(2,9-dimethyl-1,10-phenanthroline) / AlEt33, NdV / Al32Et3Cl3 / Al(i-butyl)2H, and mixtures thereof.

[0080] Preferably, the catalyst system (CS) containing the coordination catalyst component (CC) is NdV / Al32Et3Cl3 / Al(i-butyl)2H.

[0081] Catalyst systems (CS) containing anion initiators (AI): This catalyst system (CS) may include an anionic initiator (AI) and optionally an activating and / or modulating compound (ARC).

[0082] The anion initiator (AI) may be an alkali metal or an alkaline earth metal. In addition, the anion initiator (AI) may be a monofunctional or polyfunctional organometallic compound, preferably a monofunctional or polyfunctional organoalkali metal compound, and more preferably a monofunctional or polyfunctional organolithium compound.

[0083] The anionic initiator (AI) may be a monolithium compound of formula RLi, where R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy, and mixtures thereof.

[0084] Examples of monolithium compounds include alkyllithium compounds such as methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, pentyllithium, n-hexyllithium, n-decyllithium, and eicosyllithium; cycloalkyllithium compounds such as cyclohexyllithium and 2-(6-lithio-n-hexoxy)tetrahydropyran; alkoxylithium compounds such as lithium methoxide and lithium ethoxide; aryllithium compounds such as phenyllithium, 4-butylphenyllithium, 1-naphthyllithium, and p-tolyllitolium; and mixtures thereof.

[0085] In addition, monolithium compounds derived from lithium amides of secondary amines such as lithium pyrrolidide, piperidide, lithium diphenylamide, and mixtures thereof may be selected.

[0086] Organolithium compounds are commercially available or can be prepared by reacting the corresponding halide with elemental lithium (see, e.g., A. Streitwieser, C. Heathcock, Organische Chemie, Verlag Chemie, Weinheim 1980, pp. 192-194), or by reacting a secondary amine with an organolithium compound (see, e.g., H. Beyer, Lehrbuch der Organischen Chemie, S. Hirzel Verlag, Stuttgart 1988, pp. 185-186). However, lithium amides can also be produced in situ by reacting organolithium compounds with secondary (sec) amines.

[0087] Preferably, the monolithium compound is selected from n-butyllithium, sec-butyllithium, t-butyllithium, and mixtures thereof.

[0088] The anionic initiator (AI) may be a polylithium compound of the formula RLin, where n is 2 to 4, preferably 2, and R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy, and mixtures thereof.

[0089] Examples of polylithium compounds include hexamethylenedilithium, 1,4-dilithiobutane, 1,6-dilithiohexane, 1,4-dilithio-2-butene, 1,4-dilithiobenzene, dilithium 1,6-hexamethylenediamide, or dilithium piperazine.

[0090] Other suitable monofunctional or polyfunctional organoalkali metal compounds are described, for example, in U.S. Patent No. 5,171,800, U.S. Patent No. 6,429,273, and U.S. Patent No. 5,321,093.

[0091] The catalyst system (CS) may contain activating and / or modulating compounds (ARCs) used in conjunction with an anionic initiator (AI) in the polymerization reaction. Typical activating and / or modulating compounds (ARCs) include, among others, rate regulators (retardants), chain scalpers, and agents for controlling microstructure.

[0092] By adding rate regulators (retardants), the reaction rate can be reduced or the temperature increased without adversely affecting polymer properties, to the extent that the heat of polymerization released, even at high monomer concentrations, can be controlled. In the presence of rate regulators, side reactions that can lead to the deactivation of the growing polymer chain, such as lithium hydride elimination, are slowed down, allowing for higher temperatures than polymerization without these compounds. Carrying the reaction at higher temperatures may be necessary, for example, to handle relatively high molecular weight products or relatively high-concentration polymer solutions.

[0093] The rate regulator is preferably a compound of an element from the second or third main group or subgroup of the IUPAC periodic table. Typically, alkaline earth metal compounds having an alkyl or aryl group with 1 to 20 carbon atoms are used. Instead of alkyl or aryl metal compounds, alkyl or aryl metal halides or alkyl or aryl metal hydrides, such as diethylaluminum chloride or dibutylaluminum hydride, may also be used. Compounds having the same or different groups, or mixtures thereof, may be used.

[0094] Particularly preferred rate regulators are butylethylmagnesium, dibutylmagnesium, butyloctylmagnesium, dihexylmagnesium, diethylzinc, dibutylzinc, trimethylaluminum, triethylaluminum, tri-i-butylaluminum, tri-n-hexylaluminum, di-i-butylaluminum hydride, diethylaluminum chloride, or mixtures thereof.

[0095] Once the molecular weight increase is complete, the "living" polymer ends can be reacted with the usual chain arresters or coupling agents used in anionic polymerization.

[0096] Suitable chain arresters are proton-active substances or Lewis acids, such as water, alcohols, aliphatic carboxylic acids and aromatic carboxylic acids, phenols, and inorganic acids, such as carboxylic acids and boric acid, or mixtures thereof.

[0097] Suitable agents for controlling the microstructure include, for example, ether compounds and / or amine compounds, such as diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-butyl ether, ethylene glycol di-tert-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether, diethylene glycol di-tert-butyl ether, 2-(2-ethoxyethoxy)-2-methylpropane, triethylene glycol dimethyl ether, tetrahydrofuran, ethyltetrahydrofuryl ether, ditetrahydrofurylpropane, dioxane, trimethylamine, triethylamine, N,N,N',N'-tetramethylethylenediamine, N-methylmorpholine, N-ethylmorpholine, 1,2-dipiperidinoethane, 1,2-dipyrrolidinoethane and / or 1,2-dimorpholinoethane, and mixtures thereof.

[0098] The agent used to control the microstructure is preferably N,N,N',N'-tetramethylethylenediamine.

[0099] Polymers can be modified with polyfunctional compounds, such as polyfunctional aldehydes, ketones, esters, tin halides or silane halides, organosilanes, epoxides, or mixtures thereof, to increase their molecular weight or modify their branched structure. The compounds used to modify the polymer are not particularly limited and are selected as needed. [Brief explanation of the drawing]

[0100] [Figure 1] A schematic diagram of a process according to a preferred embodiment of the present invention. [Modes for carrying out the invention]

[0101] Experiment Department An embodiment of the process of the present invention was carried out at the following pilot plant. Figure 1 shows a schematic diagram.

[0102] The pilot plant consists of two high-viscosity reactors. Polymerization takes place in the first high-viscosity reactor (polymerization reactor), while the second high-viscosity reactor is used as a degassing device.

[0103] In this test setup, both the polymerization reactor and the degasser have a reaction volume of 1 liter and can be temperature-controlled via jackets and thermostats. In this test setup, the polymerization reactor is designed as a single-screw reactor with a counter hook, and the degasser is designed as a twin-screw reactor. This allows for the continuous separation and mixing of reaction masses in both high-viscosity reactors (polymerization reactor and degasser). In addition, the shafts of the single-screw reactor can be cleaned, and the shafts of the twin-screw reactors can clean each other. Furthermore, the inner surfaces of the housings of the two high-viscosity reactors can be cleaned.

[0104] A pump can transport liquid monomer from a storage tank to the polymerization reactor via a metering line. The metering line and pump can be cooled with chilled water. Furthermore, the catalyst or initiator system to be used can be transported to the polymerization reactor using a suitable pump to initiate polymerization. The heat of reaction released during polymerization can be dissipated via condensation cooling. For this purpose, an overhead cooler is installed in the polymerization reactor. The condensate can be returned from the overhead cooler to the storage tank.

[0105] The polymer from the polymerization reactor can be transported from the polymerization reactor to the degasser by a discharge screw. To start the polymerization reactor, the connection between the two high-viscosity reactors can be disconnected. During continuous operation, the connection is sealed by the generated polymer.

[0106] To deactivate the polymerization catalyst or initiator, a termination agent solution can be added to the degasser. If necessary, a stabilizer (e.g., an oxidizing or UV stabilizer) can also be added at this stage. Furthermore, unreacted monomers can be removed from the polymer by creating a vacuum with a vacuum pump (rotary vane pump). The polymer can then be discharged from the degasser using a discharge screw. The degasser is sealed from the atmosphere by the polymer during continuous operation or by a sealing plug during startup.

[0107] Before actually carrying out the process according to the present invention, the following preparations are made.

[0108] The monomers used must have a purity suitable for the polymerization mechanism used, or be purified accordingly. Appropriate methods are known to those skilled in the art. For example, trace amounts of water can be separated using molecular sieve columns. Polymerization stabilizers can be separated by re-condensation before polymerization.

[0109] First, the test apparatus is deactivated. This is done by repeatedly pressurizing the apparatus with nitrogen and then evacuating it.

[0110] Next, the polymerization reactor and degassing unit are brought to the desired process temperature using appropriate thermostats, and the cooling and feeding lines of the condenser are opened.

[0111] The reactor can be started either empty or filled with polymer.

[0112] If the reactor is started empty, the connection between the polymerization reactor and the degassing unit is first disconnected. Polymerization is started by continuously feeding the monomer and catalyst or initiator system into the polymerization reactor using an appropriate feed pump.

[0113] Reaction heat is released as a result of polymerization. This reaction heat is dissipated through the evaporation of the added liquid monomer. Unreacted gaseous monomer is removed from the reactor via an external overhead cooler (boiling / condensation cooling). The temperature inside the reactor can be controlled according to the mass flow rate of the added monomer (and catalyst). The pressure inside the reactor regulates itself according to the reaction temperature and condensation temperature. Therefore, the pressure inside the reactor can be influenced by adjusting the condensation temperature (temperature and flow rate of the coolant in the cooler).

[0114] Once the polymerization reactor is sufficiently filled by polymerization so that the discharge screw can ensure a proper seal, the shut-off valve is opened, and the discharge screw continuously discharges the polymer from the polymerization reactor into the degasser.

[0115] In the degasser, the catalyst system or initiator system can be inactivated by continuously adding a termination solution as needed, and the polymer can be stabilized with an appropriate stabilizer as needed. The remaining monomer is removed by applying a vacuum. Once the degasser is fully filled, the degassed polymer can be continuously discharged from the degasser by a discharge screw after opening the sealing plug as needed. [Examples]

[0116] chemicals catalyst: Neodymium catalyst, type COMCAT Nd-FC20 / G3, with Nd concentration of 0.0554 mol / l, from Comar Chemicals Ltd.

[0117] monomer: 1,3-butadiene with a purity of 2.3, manufactured by Gehrling & Holz. The stabilizer 4-butylcatechol contained within was separated by re-condensation.

[0118] Inhibitor: 1-Octanol Sigma Aldrich, Purity >99%

[0119] Abbreviation Bd 1,3-butadiene BR Polybutadiene rubber

[0120] Example 1: Coordination polymerization of 1,3-butadiene using an Nd catalyst The thermostat of the polymerization reactor is heated to 65°C, and the thermostat of the degassing device is heated to 50°C. The condensation temperature is set to approximately 25°C. The butadiene flow is started at 1.7 l / h, and the catalyst flow is started at 5 μl / s.

[0121] After the initial phase, a pressure in the reactor is established in the range of 2.7–3.3 bar. Four temperature measurements within the reactor show temperatures of 52–60°C (a slight temperature gradient along the length of the reactor).

[0122] After filling the reactor and degasser, approximately 290 g / h is continuously discharged from the plant. The discharged polymer no longer emits the odor of 1,3-butadiene, but it does emit the odor of the stopper 1-octanol. 1 The 1,4-cis content of the polymer, as determined by 1H-NMR, is higher than 95%.

Claims

1. A method for polymerization of monomers in the gas phase, a) A step of continuously supplying monomers to the reactor, b) A step of contacting the monomer in the reactor with a homogeneous catalyst system or a homogeneous initiator system to obtain a polymerizable mixture, c) A step of polymerizing the polymerizable mixture in the reactor to obtain a polymer, d) A step of continuously discharging the polymer from the reactor. Includes, The monomer is a molecule containing an unsaturated bond involving a carbon atom, The reactor includes a device for crushing and mixing the aggregated polymer. The reactor is connected to a cooler that allows monomers to be collected from the reactor, condensed, and the condensed monomers to be returned to the reactor. The above method is carried out such that the vapor pressure of each monomer in the reactor is always higher than its partial pressure in the reactor. method.

2. The method according to claim 1, wherein the polymer obtained according to step c) is mixed in the reactor by the apparatus for crushing and mixing aggregated polymers, or crushed and mixed.

3. The method according to claim 1 or 2, wherein the polymer is discharged from the reactor by a screw.

4. The method according to any one of claims 1 to 3, wherein the polymer is discharged from the reactor in a non-particulate form.

5. The method according to any one of claims 1 to 4, wherein the polymer is degassed after being discharged from the reactor.

6. The method according to any one of claims 1 to 5, wherein the reactor is a high-viscosity reactor.

7. The method according to claim 6, wherein the high-viscosity reactor is a first high-viscosity reactor connected to a second high-viscosity reactor which includes a device for degassing the polymer, and the polymer is discharged from the first high-viscosity reactor into the second high-viscosity reactor according to step d).

8. The method according to any one of claims 1 to 7, wherein the sum of the masses of the monomer, the homogeneous catalyst system or homogeneous initiator system, and the polymer accounts for at least 90% of the total mass of all substances in the reactor.

9. The method according to any one of claims 1 to 8, wherein the total mass of the solvent, diluent, and dispersant present in the reactor accounts for a maximum of 10% of the total mass of all substances present in the reactor.

10. The method according to any one of claims 1 to 9, wherein the condition that the vapor pressure of each monomer in the reactor is always higher than its partial pressure in the reactor is maintained by setting appropriate conditions in the reactor.

11. The method according to any one of claims 1 to 10, wherein the monomer is discharged from the reactor, condensed in the cooler, and returned to the reactor.

12. The method according to any one of claims 1 to 11, wherein the monomer is selected from the group consisting of ethylene, α-olefins having 3 to 8 carbon atoms, dienes having 4 to 8 carbon atoms, and mixtures thereof.

13. The method according to any one of claims 1 to 11, wherein the monomer is selected from the group consisting of ethylene, propylene, isobutene, styrene, α-methylstyrene, 4-methylstyrene, ethyl acrylate, methyl methacrylate, ethyl methacrylate, maleic anhydride, acrylonitrile, 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 1,3-heptadiene, 2,4-heptadiene, 2-methyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, and mixtures thereof.

14. The method according to any one of claims 1 to 13, wherein the monomer consists of at least 50 mol% 1,3-butadiene based on the total amount of all monomers supplied to the reactor in step a).

15. The method according to any one of claims 1 to 14, wherein the monomer comprises 1,3-butadiene.

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