Gas-phase polymerization with homogeneous catalyst or initiator systems

Abstract

The present invention relates to a continuous process for the polymerization of monomers in the gas phase using homogeneous catalyst or initiator systems in a reactor containing devices for comminuting and mixing agglomerated polymer. The process is conducted such that the vapor pressure of each monomer in the reactor is always greater than its partial pressure in the reactor. This condition is maintained in the process by adjusting suitable conditions in the reactor. For this purpose, the pressure and temperature in the reactor are adjusted accordingly. Monomers that have not been polymerized can be condensed in a condenser and returned to the reactor. Under the conditions prevailing in the reactor, the monomers evaporate and provide a cooling effect. This also applies if the monomers are generally introduced into the reactor in liquid form.Furthermore, the condensation of the monomers in the condenser causes the pressure in the reactor to decrease.

Description

[0001] The present invention is directed to a process for the polymerization of monomers in the gas phase. This process utilizes homogeneous catalyst or initiator systems.

[0002] Polymerization is a chemical reaction in which monomers react to form polymers. The monomers are usually unsaturated organic compounds. The reaction proceeds with the dissolution of a multiple bond within the monomer and the formation of single bonds between the monomers. Polymers are therefore molecules with long chains consisting of interconnected monomers. A distinction is made between homopolymerization, in which only one type of monomer is reacted, and copolymerization, in which two or more different monomers are reacted. The reaction proceeds under the influence of catalysts or after initiation by initiators. Those skilled in the art are familiar with a variety of catalyst and initiator systems, which are selected depending on the monomers to be polymerized. These catalyst and initiator systems can be homogeneous or heterogeneous. Homogeneous systems do not contain any support materials.

[0003] Various processes for the polymerization of monomers are known to the person skilled in the art, such as gas phase polymerization, solution polymerization and bulk polymerization.

[0004] Gas-phase polymerization is used on a large scale for the production of polyolefins such as polyethylene and polypropylene. Gas-phase polymerization takes place in the gaseous monomer. It uses catalysts immobilized on support materials such as silicon dioxide or magnesium dichloride particles. The reaction takes place on and within the particles at the active sites of the catalyst. The catalyst particles are thus transformed into polymer particles, which can be considered microreactors. The polymers therefore contain the catalyst particles, which can be a disadvantage for certain applications requiring high purity. Homopolymers and copolymers of propylene and ethylene can be obtained in this way.The polymers obtained consist of chains that do not have large branches, apart from the relatively short branches that are due to the structure of the monomers, such as the methyl side chains in polypropylene or the ethyl side chains when using 1-butene or the butyl side chains when using 1-hexene as comonomers.

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

[0006] The known processes must always be conducted in such a way that agglomerates of the formed polymer are avoided as much as possible. The occurrence of agglomerates can seriously disrupt the processes and regularly results in the process having to be stopped and the reaction vessels and other parts of the plant having to be extensively cleaned. This involves a very high level of effort and expense.

[0007] The risk of agglomeration and the associated problems are the reason why an important industrial product, synthetic rubber, is not manufactured industrially using gas-phase polymerization. Synthetic rubber exhibits high stickiness, which leads to agglomeration of the polymer particles.

[0008] Although the use of gas-phase polymerization to produce synthetic rubber has been described in scientific literature and patent applications, the problem of agglomeration has not been satisfactorily resolved.

[0009] For gas-phase polymerization to produce synthetic rubber, fluidized bed reactors or stirred beds are typically used. As mentioned above, it is important to avoid particle agglomeration, as this leads to operational problems (sheeting, chunking, reduced fluidization) and, as a result, to overheating, the formation of hot spots, and ultimately to product damage to the synthetic rubber. This results in synthetic rubber of inferior quality.

[0010] One way to prevent agglomeration is to use powdering agents such as silica or carbon black, which adhere to the surface of the sticky synthetic rubber particles. However, the use of powdering agents leads to other problems.

[0011] Solution polymerization is used industrially to produce synthetic rubber. Because the polymerization takes place in a solvent, polymer particles do not form in a separate phase, thus preventing agglomeration. A disadvantage of this process is that large quantities of solvent are required, which then have to be laboriously removed from the polymer product. The solvent separated from the polymer product must then be purified and returned to the process. Separating and purifying the solvent are very energy- and cost-intensive and significantly increase the carbon footprint of synthetic rubber production. Furthermore, the polymer product may contain solvent impurities.

[0012] There is therefore a great need for a method that allows the known problems to be solved.

[0013] The present invention is accordingly directed to a process for the polymerization of monomers in the gas phase, which comprises the following steps: a) continuous introduction of monomers into a reactor; b) contacting the monomers in the reactor with a homogeneous catalyst or initiator system and obtaining a mixture capable of polymerisation; c) polymerisation of the mixture capable of polymerisation in the reactor and obtaining a polymer; d) continuously discharging the polymer from the reactor; where - the monomers are molecules containing an unsaturated bond involving a carbon atom; - the reactor contains devices for crushing and mixing agglomerated polymer; - the reactor is connected to a condenser which allows monomers to be taken up from the reactor, condensed, and condensed monomers to be reintroduced into the reactor; and - the process is conducted in such a way that the vapor pressure of each monomer in the reactor is always greater than its partial pressure in the reactor.

[0014] The present invention solves several of the above-mentioned problems by providing a process that allows monomers to be polymerized in the gas phase using homogeneous catalyst systems or homogeneous initiator systems. The polymers therefore do not contain any residues of support materials. The process takes place in a reactor that allows any agglomerates that occur to be comminuted and mixed. Accordingly, the formation of agglomerates does not disrupt the process or impair the product quality. The condenser can receive and condense (gaseous) monomers. The condensed monomers can be reintroduced into the reactor. The process is conducted such that the vapor pressure of each monomer, i.e., the monomers of one monomer type (homopolymerization) or of all monomers in the case of different monomer types (copolymerization), in the reactor is always greater 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, condensed monomers introduced into the reactor via the condenser evaporate in the reactor. The same applies, of course, if liquid monomers are introduced into the reactor according to step a) of the process of the present invention.

[0015] The introduction of the monomers and the discharge of the polymer take place continuously, ie 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 greater than its partial pressure in the reactor is maintained in the process according to the present invention by setting suitable conditions in the reactor. The pressure and temperature in the reactor are adjusted accordingly.

[0017] Those skilled in the art are aware that polymerization involves the development of heat. This heat must be dissipated to prevent overheating. Those skilled in the art are familiar with suitable measures for this.

[0018] In the process according to the present invention, monomers (which have not been polymerized) can be condensed in the condenser and reintroduced into the reactor. Under the conditions prevailing in the reactor, the monomers evaporate, providing a cooling effect. Furthermore, the condensation of the monomers in the condenser leads to a drop in pressure in the reactor.

[0019] The extent of condensation of the monomers in the condenser can be controlled by the condenser's cooling capacity. For example, the temperature of a coolant in the condenser and / or its flow rate can be adjusted. This allows pressure and temperature in the reactor to be regulated.

[0020] The pressure in the reactor can also be regulated by introducing the monomers according to step a) and by discharging the polymer according to step d) of the process of the present invention.

[0021] In the process according to the present invention, liquid monomers are preferably introduced into the reactor in step a). The liquid monomers evaporate under the conditions prevailing in the reactor and provide a cooling effect. In this way, the temperature in the reactor can be regulated by the rate at which the monomers are introduced into the reactor.

[0022] The rate of introduction of the homogeneous catalyst or initiator system can also be used to regulate the temperature in the reactor, as this allows the extent of polymerization to be regulated.

[0023] Compared to solution polymerization, the process of the present invention has the advantage that no solvents need to be used, separated, or purified. This makes the process of the invention significantly more energy- and resource-efficient and more cost-effective.

[0024] Compared to 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 not susceptible to agglomeration. This also eliminates the need for powdering agents to prevent or reduce agglomeration in the case of very sticky polymers such as synthetic rubber. Furthermore, supported catalysts are not required. Instead, conventional homogeneous catalysts, such as those known from solution polymerization, can be used. This reduces the effort and material consumption, thus lowering the process costs. Furthermore, the polymers contain no residues of the support materials.

[0025] According to a preferred embodiment of the process of the present invention, the polymer obtained according to step c) is mixed in the reactor by means of the devices for comminuting and mixing agglomerated polymer, further preferably continuously mixed, or comminuted and mixed, further preferably continuously comminuted and mixed, similar to a meat grinder.

[0026] Suitable devices for comminuting and mixing agglomerated polymer are known to the person skilled in the art.

[0027] The devices for comminuting and mixing agglomerated polymer in the reactor can be designed based on single- or twin-shaft apparatus. The only important thing is that the devices for comminuting and mixing agglomerated polymer can be used to comminute and mix the polymer obtained in step c) in the reactor. This means that the shafts and the internal surfaces of the reactor can be cleaned. In the case of a single-shaft reactor, additional counterhooks (scrapers) can be provided in the reactor for this purpose. In the case of a twin-shaft reactor, these counterhooks (scrapers) can also be provided and / or the shafts can clean each other.

[0028] The monomers are usually fed from a storage container via a dosing line into the reactor according to step a).

[0029] If the monomers contain polymerization stabilizers, these can be separated before polymerization in the usual way, e.g. by recondensation.

[0030] According to a preferred embodiment of the process of the present invention, a pump conveys the monomer from a storage container via a metering line into the reactor. Furthermore, devices are preferably provided that allow the metering line and the pump to be cooled with cold water.

[0031] According to a preferred embodiment of the process of the present invention, the condenser also has a storage vessel in which the condensed monomer can be collected and fed into the reactor as needed. It is further preferred that the storage vessel of the condenser be identical to the aforementioned storage vessel.

[0032] According to a preferred embodiment of the process of the present invention, the polymer is continuously discharged from the reactor by a screw.

[0033] According to a preferred embodiment of the process of the present invention, the polymer is continuously discharged from the reactor in non-particulate form.

[0034] According to a preferred embodiment of the process of the present invention, the polymer is degassed after being discharged from the reactor. Degassing takes place under vacuum.

[0035] According to a preferred embodiment of the process of the present invention, the polymerization is stopped in the usual way by adding a stopper and optionally a stabilizer to the discharged polymer, and the polymer is optionally stabilized. Suitable stoppers and stabilizers are known to those skilled in the art.

[0036] According to a preferred embodiment of the process of the present invention, the reactor is a high-viscosity reactor. High-viscosity reactors are known to those skilled in the art. Furthermore, the high-viscosity reactor preferably contains counter-hooks (scrapers) that prevent polymer from sticking to a shaft of the high-viscosity reactor.

[0037] According to the same preferred embodiment of the process of the present invention, a second high-viscosity reactor, into which the polymer is continuously discharged from the first high-viscosity reactor, further preferably by means of a screw, is further preferably coupled to the high-viscosity reactor in which the polymerization takes place. The polymer is further preferably continuously discharged from the first high-viscosity reactor in non-particulate form. Further preferably, stoppers and optionally stabilizers are added to the polymer in the second high-viscosity reactor. Further preferably, the second high-viscosity reactor comprises a device for degassing the polymer. Further preferably, the polymer is degassed under vacuum in the second high-viscosity reactor. The finished polymer is conveyed from the second high-viscosity reactor through a discharge opening, further preferably by means of a discharge screw.

[0038] The connection between the first high-viscosity reactor and the second high-viscosity reactor can be shut off for start-up purposes. Likewise, the discharge opening of the second high-viscosity reactor can be closed for start-up purposes.

[0039] The first high-viscosity reactor and the second high-viscosity reactor can preferably be temperature-controlled via a jacket and thermostats. The first high-viscosity reactor preferably also contains counterhooks (scrapers) to prevent polymer from sticking to a shaft of the first high-viscosity reactor. The second high-viscosity reactor preferably also contains counterhooks (scrapers) to prevent polymer from sticking to a shaft of the second high-viscosity reactor.

[0040] An overhead condenser with a storage tank is preferably attached to the first high-viscosity reactor, which allows condensate to flow into the storage tank and from there be introduced into the first high-viscosity reactor.

[0041] According to a preferred embodiment of the process of the present invention, the sum of the masses of the monomers, the homogeneous catalyst or initiator system, and the polymer constitutes at least 90% of the total mass of all substances present in the reactor. Further preferably, this sum constitutes at least 95% of the total mass of all substances present in the reactor. This sum can constitute up to 100% of the total mass of all substances present in the reactor.

[0042] The process according to the present invention does not require the addition of solvents, diluents and dispersants.

[0043] Accordingly, according to a preferred embodiment of the process of the present invention, the sum of the masses of solvents, diluents, and dispersants present in the reactor makes up at most 10% of the total mass of all substances present in the reactor, more preferably makes up at most 5.0% of the total mass of all substances present in the reactor, more preferably makes up at most 3.0% of the total mass of all substances present in the reactor, and more preferably makes up at most 1.0% of the total mass of all substances present in the reactor. This sum can also make up as little as 0.1% of the total mass of all substances present in the reactor, and this sum can also be 0.0%.

[0044] The present invention is generally directed to a process for the polymerization of monomers in the gas phase and is therefore not limited to specific monomers. The monomers are molecules that contain an unsaturated bond involving one, i.e., at least one, carbon atom. Suitable monomers must therefore contain at least one polymerizable multiple bond (double bond or triple bond) involving a carbon atom. The selection of suitable monomers naturally depends on the polymer to be produced.

[0045] Typical monomers are olefins such as ethylene, α-olefins and dienes, acrylic acid esters, methacrylic acid esters, maleic anhydride, nitriles, and styrenes.

[0046] The process according to the present invention can be carried out as a homo- or co-polymerization using typical monomers.

[0047] According to a preferred embodiment of the process of the present invention, the monomers are molecules containing an unsaturated carbon-carbon bond (double bond or triple bond). Furthermore, the monomers are preferably hydrocarbons, i.e., the monomers consist of carbon and hydrogen atoms and do not contain any other so-called heteroatoms.

[0048] According to a preferred embodiment of the process of the present invention, the monomers are selected from the group consisting of ethylene, α-olefins having three to eight carbon atoms, dienes having four to eight carbon atoms, and mixtures thereof.

[0049] According to a further preferred embodiment of the process of the present invention, the monomers are 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.

[0050] For example, the monomers can consist of a mixture of ethylene, propylene, and a diene. The resulting copolymer contains polymer units derived from ethylene, polymer units derived from propylene, and polymer units derived from a diene and is known as ethylene-propylene-diene rubber (EPDM) and is technically relevant as a synthetic rubber.

[0051] According to a further preferred embodiment of the process of the present invention, the monomers consist of at least 50 mol% 1,3-butadiene. In this preferred embodiment, the process of the invention therefore leads to the production of a polymer containing polymer units derived from 1,3-butadiene.

[0052] The rest of the monomers can belong to one or more other monomer types, resulting in a copolymer of 1,3-butadiene.

[0053] For example, the monomers can 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 relevant as a synthetic rubber.

[0054] It is further preferred that the monomers consist of at least 60 mol% of 1,3-butadiene, further preferably at least 70 mol% of 1,3-butadiene, further preferably at least 80 mol% of 1,3-butadiene, further preferably at least 90 mol% of 1,3-butadiene, based on the total amount of all monomers introduced into the reactor in step a).

[0055] In this preferred embodiment, the process according to the invention therefore leads to the production of a polymer which contains polymer units derived from 1,3-butadiene, further preferably consists of at least 50 mol% of polymer units derived from 1,3-butadiene, even more preferably consists of at least 60 mol% of polymer units derived from 1,3-butadiene, even more preferably consists of at least 70 mol% of polymer units derived from 1,3-butadiene, even more preferably consists of at least 80 mol% of polymer units derived from 1,3-butadiene, and even more preferably consists of at least 90 mol% of polymer units derived from 1,3-butadiene.

[0056] According to a further preferred embodiment of the process of the present invention, the monomers consist of 1,3-butadiene.

[0057] In this preferred embodiment, the process according to the invention therefore leads to 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 industrially relevant as a synthetic rubber.

[0058] According to a preferred embodiment of the process of the present invention, the monomers and a homogeneous catalyst or initiator system are continuously introduced into the reactor.

[0059] In step b) of the process of the present invention, the monomers in the reactor are contacted with a homogeneous catalyst or initiator system and a mixture capable of polymerization is obtained.

[0060] The process according to the present invention employs conventional homogeneous catalyst or initiator systems. These catalysts or initiators are known to those skilled in the art.

[0061] Initiators are used, for example, in radical polymerization. Typically, peroxides or azo compounds are used as initiators. Initiators are also used in anionic polymerization. A typical initiator here is butyllithium.

[0062] Typical catalyst or initiator systems are listed below: In the following section, the term “catalyst system (CS)” is used for typical catalyst or initiator systems. This includes both (a) catalyst systems based on coordination catalysts, such as Ziegler-Natta catalysts and metallocene catalysts, which increase the reaction rate by reducing the activation energy without being consumed in addition polymerization, in which a monomer is added to a growing macromolecule via an organometallic active center; and (b) Catalyst systems based on anionic initiators, such as alkyl lithium initiators, which is carried out by an active carbanion species that is consumed by the polymerization process and induces a form of chain growth polymerization or addition polymerization involving the polymerization of monomers with olefin moieties induced by strong electronegative groups.

[0063] The catalyst system (CS) may comprise a coordination catalyst component (CC) and optionally a co-catalyst component (Co), wherein the coordination catalyst component (CC) is based on a transition metal of groups 4 to 10 of the Periodic Table and / or rare earth metals, preferably the coordination catalyst component (CC) is based on titanium, chromium, vanadium, cobalt, nickel, zirconium, neodymium, gadolinium or mixtures thereof.

[0064] The catalyst system (CS) may comprise an anionic initiator (AI) and optionally activating and / or regulating compounds (ARC), wherein the anionic initiator (AI) is a mono- or polyfunctional organic metal compound, preferably a mono- or polyfunctional organic alkali metal compound, preferably a mono-lithium compound, represented by the formula RLi, wherein R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy and mixtures thereof.

[0065] Catalyst systems (CS) with coordination catalyst components (CC): The catalyst system (CS) may comprise a coordination catalyst component (CC) and optionally a co-catalyst component (Co).

[0066] The coordination catalyst component (CC) can be a coordination catalyst based on a transition metal from groups 4 to 10 of the Periodic Table and / or on rare earth metals; preferably, the coordination catalyst component (CC) is a coordination catalyst based on titanium, chromium, vanadium, cobalt, nickel, zirconium, neodymium, gadolinium, and mixtures thereof; more preferably, the coordination catalyst component (CC) is a coordination catalyst based on titanium, nickel, neodymium, and mixtures thereof; even more preferably, the coordination catalyst component (CC) is a coordination catalyst based on neodymium.

[0067] Examples of coordination catalyst components (CC) 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, (1,2,3,4-tertamethylcyclopentadienyl)VCl3 CrCl2 (1,2-bis(dimethylphosphino)ethane)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(BH )43, Gd(2,9-dimethyl-1,10-phenanthroline)3, NdV3, and mixtures thereof.

[0068] The coordination catalyst component (CC) is preferably NdV3 .

[0069] The co-catalyst component (Co) is used to improve the catalytic activity of the catalyst system (CS). The co-catalyst component (Co), which is used in conjunction with a coordination catalyst component (CC), is typically an organometallic compound based on alkaline earth metals or an organometallic compound based on the boron group of the periodic table. Preferably, the co-catalyst component (Co) is an organomagnesium compound or an organoaluminum compound, with the latter being particularly preferred.

[0070] The co-catalyst component (Co) can be an organoaluminum compound, including those represented by the formula AIR Xn3-n, wherein each R, which may be the same or different, is a monovalent organic group bonded to the aluminum atom through a carbon atom, wherein each X, which may be the same or different, is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and wherein n is an integer from 1 to 3. Each R can be a hydrocarbon group, such as, but not limited to, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl, alkylaryl, and alkynyl groups. These hydrocarbon groups can contain heteroatoms such as, but are not limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

[0071] 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, tri-hexylaluminum, tri-n-octylaluminum, di-ibutylaluminum hydride, di-secbutylaluminum hydride, methylaluminumoxane (MAO), hexa-ibutylaluminumoxane (HIBAO), and tetra-ibutylaluminumoxane (TIBAO), and mixtures thereof. Preferably, the co-catalyst component (Co) is selected from tri-ethylaluminum, diethylaluminum chloride, tri-ibutylaluminum, ethylaluminum dichloride, di-ibutylaluminum hydride, methylaluminumoxane (MAO), and mixtures thereof.

[0072] The co-catalyst component (Co) can be an organomagnesium compound, including those represented by the formula MgR Xn2-n, wherein each R, which may be the same or different, is a monovalent organic group bonded to the magnesium atom through a carbon atom, wherein each X, which may be the same or different, is a hydrogen atom, a halogen atom, a carboxylate group, an alkoxide group, or an aryloxide group, and wherein n is an integer from 1 to 3. Each R can be a hydrocarbon group, such as, but not limited to, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl, alkylaryl, and alkynyl groups. These hydrocarbon groups can contain heteroatoms such as, but are not limited to, nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

[0073] Examples of co-catalyst components (Co) include, but are not limited to, dialkylmagnesium such as diethylmagnesium, di-n-butylmagnesium, di-ibutylmagnesium, di-sec-butylmagnesium, ethylbutylmagnesium; alkylmagnesium halides such as ethylmagnesium chloride, i-butylmagnesium chloride, sec-butylmagnesium chloride, n-butylmagnesium chloride; dialkoxymagnesium such as diethoxymagnesium, di-ipropoxymagnesium, di-n-butoxymagnesium, di-ibutoxymagnesium, di-sec-butoxymagnesium, di-ethylhexoxymagnesium and diphenoxymagnesium; alkoxymagnesium halides such as methoxymagnesium chloride, ethoxymagnesium chloride and phenoxymagnesium chloride; magnesium carboxylates such as magnesium stearate; and the like. Preferably, the co-catalyst component (Co) is selected from di-n-butylmagnesium.

[0074] Examples of catalyst systems (CS) comprising a coordination catalyst component (CC) include TiCl / AlEt33, Ti(O nBu) / AlEt43, Ti(O nBu) / Al-i-Bu43, Ti(O nBu) / AlEtCl42 / MAO, Ti(O nBu)4 / MAO, CpTiCl3 / MAO, Ti(CH2Ph)4 / MAO, VCl / AlEt33, CrCl2(1,2-bis(dimethylphosphino)ethane)2 / MAO, Co(acetylacetonate)3 / MAO, Co(acetylacetonate) / AlEt33CI / H2O, Ni(carboxylate) / AlEt / BF2332, OEtNi(acetylacetonate)2 / MAO, NiCl3, Ni(octanoate) / AlEt / BF233, Nd(1,5-cyclooctadiene) / B(CF )653, Nd(carboxylate)3, Nd(octanoate) / AlEt32 Cl / Al(i-Bu)3, Nd(BH ) / AlEt433, Nd(BH )43 (THF) / AlEt33 , Nd(BH )43 (THF) / Bu Mg32, Gd(2,9-dimethyl-1,10-phenanthroline) / AlEt33, NdV / Al32 Et3 Cl3 / Al(i-butyl)2 H, and mixtures thereof.

[0075] Preferably, the catalyst system (CS) containing a coordination catalyst component (CC) is NdV / Al32 Et3 Cl3 / Al(i-butyl)2 H.

[0076] Catalyst systems (CS) with anionic initiators (Al): The catalyst system (CS) may comprise an anionic initiator (AI) and optionally activating and / or regulating compounds (ARC).

[0077] The anionic initiator (AI) can be an alkali metal or an alkaline earth metal. Furthermore, the anionic initiator (AI) can be a mono- or polyfunctional organic metal compound, preferably a mono- or polyfunctional organic alkali metal compound, more preferably a mono- or polyfunctional organolithium compound.

[0078] The anionic initiator (AI) can be a mono-lithium compound of the formula RLi, in which R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy and mixtures thereof.

[0079] Examples of monolithium compounds include, among others, alkyllithium compounds such as methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, pentyllithium, n-hexylithium, n-decyllithium, 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-tolyllithium; and mixtures thereof.

[0080] In addition, mono-lithium compounds can be selected from lithium amides of secondary amines, such as lithium pyrrolidide, piperididide, lithium diphenylamide and mixtures thereof.

[0081] The organolithium compounds are commercially available or can be prepared by reacting the corresponding halides with elemental lithium (see, for example, BA Streitwieser, CH Heathcock, Organic Chemistry, Verlag Chemie, Weinheim 1980, pp. 192-194) or by reacting secondary amines with organolithium compounds (see, for example, BH Beyer, Textbook of Organic Chemistry, S. Hirzel Verlag, Stuttgart 1988, pp. 185-186). However, the lithium amides can also be prepared in situ by reacting an organolithium compound with secondary (sec) amines.

[0082] Preferably, the monolithium compound is selected from n-butyllithium, sec-butyllithium, t-butyllithium and mixtures thereof.

[0083] The anionic initiator (AI) can be a polylithium compound of the formula RLin, in which n is 2 to 4, preferably 2, and in which R is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, alkoxy, heteroalkyl, heteroalkenyl, heteroalkynyl, arylalkyl, arylalkenyl, aryl, aryloxy and mixtures thereof.

[0084] 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 piperazide.

[0085] Other suitable mono- or polyfunctional organic alkali metal compounds are described, for example, in US Pat. Nos. 5,171,800; 6,429,273 and 5,321,093.

[0086] The catalyst system (CS) can contain activating and / or regulating compounds (ARCs) that are used together with the anionic initiator (AI) in the polymerization reaction. Typical activating and / or regulating compounds (ARCs) include rate regulators (retarders), chain terminators, and microstructure control agents.

[0087] By adding rate regulators (retarders), the reaction rate can be reduced or the temperature increased without adversely affecting the polymer properties, allowing the released heat of polymerization to be controlled even at high monomer concentrations. In the presence of rate regulators, side reactions that can lead to deactivation of the growing polymer chain—such as lithium hydride eliminations—are slowed down, allowing higher temperatures than in polymerization without these compounds. Conducting the reaction at higher temperatures may be necessary, for example, for handling relatively high-molecular-weight products or relatively highly concentrated polymer solutions.

[0088] The rate regulator is preferably a compound of an element from the second or third main group or subgroup of the IUPAC Periodic Table of Elements. Typically, alkaline earth metal compounds with alkyl or aryl radicals containing 1 to 20 carbon atoms are used. Instead of alkyl or arylmetal compounds, alkylmetal or arylmetal halides or alkylmetal or arylmetal hydrides, e.g., diethylaluminum chloride or dibutylaluminum hydride, can also be used. Compounds with identical or different radicals, or mixtures thereof, can be used.

[0089] 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.

[0090] Once the molecular weight increase is complete, the “living” polymer ends can be reacted with the usual chain terminators or coupling agents for anionic polymerizations.

[0091] Suitable chain terminators are proton-active substances or Lewis acids, e.g., water, alcohols, aliphatic and aromatic carboxylic acids, phenols, and inorganic acids, such as carboxylic acid and boric acid, or mixtures thereof.

[0092] Suitable agents for controlling the microstructure are, for example, ether 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, ethyl tetrahydrofuryl 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.

[0093] The microstructure control agent is preferably N,N,N',N'-tetramethylethylenediamine.

[0094] The polymers can be modified with polyfunctional compounds, such as polyfunctional aldehydes, ketones, esters, tin or silane halides, organosilanes, epoxides, or mixtures thereof, to increase the molecular weight or adjust the branching structure. The compounds used to modify the polymers are not particularly limited and are selected as needed. List of illustrations Fig. : Scheme of the process according to a preferred embodiment of the present invention. Experimental part

[0095] The examples of the process of the present invention were carried out in a pilot plant, which is described below. Fig. shows a schematic representation.

[0096] The pilot plant consists of two high-viscosity reactors. The first high-viscosity reactor (polymerization reactor) is used for polymerization, while the second high-viscosity reactor serves as a degasser.

[0097] In this pilot plant, both the polymerization reactor and the degasser have a reaction volume of 1 liter and can be temperature-controlled via a jacket and thermostats. In this pilot plant, the polymerization reactor is designed as a single-shaft reactor with a counter-hook, and the degasser is a twin-shaft reactor. This allows the reaction mass in both high-viscosity reactors (polymerization reactor and degasser) to be continuously divided and mixed. Furthermore, the shaft of the single-shaft reactor can be cleaned, and the shafts of the twin-shaft reactor can clean each other. Furthermore, the inner surfaces of the housings of both high-viscosity reactors can be cleaned.

[0098] A pump can transport the liquid monomer from a storage tank via a metering line into the polymerization reactor. It is possible to cool the metering line and the pump with cold water. Furthermore, the catalyst or initiator system used can be pumped into the polymerization reactor with a suitable pump to start the polymerization. The reaction heat released during polymerization can be removed via condensation cooling. For this purpose, an overhead condenser is attached to the polymerization reactor. The condensate can flow back from the overhead condenser into the storage tank.

[0099] The polymer from the polymerization reactor can be conveyed into the degasser via a discharge screw. To start up the polymerization reactor, the connection between the two high-viscosity reactors can be shut off. During continuous operation, the connection is sealed by the produced polymer.

[0100] A stopper solution can be added to the degasser to deactivate the polymerization catalyst or initiator. If necessary, stabilizers (e.g., oxidation or UV stabilizers) can also be added here. Furthermore, unreacted monomers can be removed from the polymer by applying a vacuum with a vacuum pump (rotary vane pump). The polymer can then be discharged from the degasser using a discharge screw. Sealing the degasser from the atmosphere is achieved by polymer during continuous operation or by a plug during startup.

[0101] Before the actual method according to the present invention is carried out, the following preparations are made.

[0102] The monomers used must be of a purity appropriate to the polymerization mechanism used, or must be purified accordingly. The corresponding methods are known to those skilled in the art. For example, traces of moisture can be removed using molecular sieve columns. Polymerization stabilizers can be removed prior to polymerization by recondensation.

[0103] The test setup is first rendered inert. This is done by repeatedly pressurizing it with nitrogen and then evacuating it.

[0104] The polymerization reactor and the degasser are then brought to the desired process temperature using the corresponding thermostats and the cooling lines of the condenser and the dosing line are opened.

[0105] The reactor can be started up either empty or filled with polymer.

[0106] When the reactor is started up empty, the connection between the polymerization reactor and the degasser is first shut off. Polymerization is initiated by continuously metering monomer and catalyst or initiator system into the polymerization reactor using the appropriate metering pumps.

[0107] Reaction heat is released during polymerization. This heat is removed by evaporation of the added liquid monomer. Unreacted gaseous monomer is removed from the reactor via the external overhead condenser (boiling / condensation cooling). The temperature in the reactor can be controlled accordingly by adjusting the flow rate of the added monomer (and also the catalyst).

[0108] The pressure in the reactor is adjusted according to the reaction and condensation temperatures. The pressure in the reactor can therefore be influenced by adjusting the condensation temperature (temperature and flow rate of the condenser's cooling medium).

[0109] When the polymerization reactor is sufficiently filled by the polymerization so that the discharge screw can ensure adequate sealing, the shut-off valve is opened and the discharge screw continuously discharges polymer from the polymerization reactor into the degasser.

[0110] In the degasser, the catalyst or initiator system can be deactivated, if necessary, by continuously adding a stopper solution, and the polymer can be stabilized with suitable stabilizers, if desired. The remaining monomer is removed by applying a vacuum. After the degasser has been sufficiently filled, the degassed polymer can be continuously discharged from the degasser via a discharge screw, if necessary after the closure plug has been opened. ChemicalsCatalyst:

[0111] Neodymium catalyst from Comar Chemicals Ltd, type COMCAT Nd-FC20 / G3 with a Nd concentration of 0.0554 mol / l Monomer:

[0112] 1,3-Butadiene from Gehrling & Holz, purity 2.3 - the stabilizer 4-butylcatechol was separated by recondensation. Stopper:

[0113] 1-Octanol Sigma Aldrich, purity >99% Abbreviations Bd 1,3-Butadien BR polybutadiene rubber

[0114] Example 1: Coordinative polymerization of 1,3-butadiene with Nd catalyst

[0115] The polymerization reactor thermostat is heated to 65 °C, and the degasser thermostat 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.

[0116] After a start-up phase, a pressure in the range of 2.7–3.3 bar is established in the reactor. The four temperature measurements in the reactor indicate temperatures of 52–60 °C (a slight temperature gradient along the reactor length).

[0117] After filling the reactor and degasser, approximately 290 g / h are continuously discharged from the plant. The discharged polymer no longer smells of 1,3-butadiene, but of the stopper 1-octanol. 1H-NMR determined 1,4-Cis content of the polymer is higher than 95%. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] A. Streitwieser, CH Heathcock, Organic Chemistry, Verlag Chemie, Weinheim 1980, pp. 192-194

[0081] H. Beyer, Textbook of Organic Chemistry, S. Hirzel Verlag, Stuttgart 1988, pp. 185-186

[0081]

Claims

[1] Process for the polymerization of monomers in the gas phase, comprising the following steps: a) continuous introduction of monomers into a reactor; b) contacting the monomers in the reactor with a homogeneous catalyst or initiator system and obtaining a mixture capable of polymerisation; c) polymerisation of the mixture capable of polymerisation in the reactor and obtaining a polymer; d) continuously discharging the polymer from the reactor; - the monomers are molecules containing an unsaturated bond involving a carbon atom; - the reactor contains devices for crushing and mixing agglomerated polymer; - the reactor is connected to a condenser which allows monomers to be taken up from the reactor, condensed, and condensed monomers to be reintroduced into the reactor; and - the process is conducted in such a way that the vapor pressure of each monomer in the reactor is always greater than its partial pressure in the reactor. [2] The process according to claim 1, wherein the polymer obtained according to step c) is mixed or is crushed and mixed in the reactor by means of the devices for crushing and mixing agglomerated polymer. [3] The process according to claim 1 or 2, wherein the polymer is discharged from the reactor by a screw. [4] The process according to any one of claims 1 to 3, wherein the polymer is discharged from the reactor in non-particulate form. [5] The process according to any one of claims 1 to 4, wherein the polymer is degassed after being discharged from the reactor. [6] The process according to any one of claims 1 to 5, wherein the reactor is a high viscosity reactor. [7] The process according to claim 6, wherein the high viscosity reactor is a first high viscosity reactor coupled to a second high viscosity reactor comprising 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 process according to any one of claims 1 to 7, wherein the sum of the masses of the monomers, the homogeneous catalyst or initiator system, and the polymer constitutes at least 90% of the total mass of all substances in the reactor. [9] The process according to any one of claims 1 to 8, wherein the sum of the masses of solvents, diluents and dispersants present in the reactor amounts to at most 10% of the total mass of all substances present in the reactor. [10] The process according to any one of claims 1 to 9, wherein the condition that the vapor pressure of each monomer in the reactor is always greater than its partial pressure in the reactor is maintained by setting suitable conditions in the reactor. [11] The process according to any one of claims 1 to 10, wherein monomers are discharged from the reactor, condensed in the condenser, and recycled to the reactor. [12] The process according to any one of claims 1 to 11, wherein the monomers are selected from the group consisting of ethylene, α-olefins having three to eight carbon atoms, dienes having four to eight carbon atoms, and mixtures thereof. [13] The process according to any one of claims 1 to 11, wherein the monomers are 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 process according to any one of claims 1 to 13, wherein the monomers consist of at least 50 mol% of 1,3-butadiene, based on the total amount of all monomers introduced into the reactor in step a). [15] The process according to any one of claims 1 to 14, wherein the monomers consist of 1,3-butadiene.

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