阅读说明：本技术 制备反-1，4-聚异戊二烯聚合物的均相催化剂、其制备方法及应用 (Homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer, preparation method and application thereof ) 是由 王萌 张�杰 郑雷 臧晓燕 荣先超 王鸿飞 李寿 蒲诚勇 于 2020-12-23 设计创作，主要内容包括：本发明属于合成反-1,4-聚异戊二烯聚合物催化剂技术领域,公开了制备反-1,4-聚异戊二烯聚合物的均相催化剂、其制备方法及应用。所述均相催化剂包括负载型钛系催化剂、AlR-3烷基铝助催化剂和聚异戊二烯聚合物；其中,所述AlR-3烷基铝助催化剂中的R为C-1-C-6的烷基,所述聚异戊二烯聚合物的数均分子量为1000-10000,所述聚异戊二烯聚合物中顺-1,4-聚异戊二烯的质量分数不低于30％。本发明所述均相催化剂为液相催化剂,这使得在工业生产和聚合过程中避免了因固体难分散而导致聚合不均匀,聚合反应难控制,产品技术指标相差大等问题。(The invention belongs to the technical field of catalysts for synthesizing trans-1, 4-polyisoprene polymers, and discloses a homogeneous catalyst for preparing trans-1, 4-polyisoprene polymers, and a preparation method and application thereof. The homogeneous catalyst comprises a supported titanium catalyst and AlR 3 An alkylaluminum cocatalyst and a polyisoprene polymer; wherein, the AlR 3 R in the alkylaluminum cocatalyst is C 1 ‑C 6 The number average molecular weight of the polyisoprene polymer is 1000-10000, and the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is not less than 30%. The homogeneous catalyst of the present invention is a liquid phase catalyst, whichThe problems of uneven polymerization, difficult control of polymerization reaction, large difference of product technical indexes and the like caused by difficult dispersion of solids in industrial production and polymerization processes are solved.)

1. A homogeneous catalyst for the preparation of trans-1, 4-polyisoprene polymer, characterized in that: comprises a supported titanium catalyst and AlR₃An alkylaluminum cocatalyst and a polyisoprene polymer; wherein, the AlR₃R in the alkylaluminum cocatalyst is C₁-C₆The number average molecular weight of the polyisoprene polymer is 1000-10000, and the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is not less than 30%.

2. The homogeneous catalyst of claim 1, wherein: the supported titanium catalyst and AlR₃The molar ratio of the alkylaluminum cocatalyst to the polyisoprene polymer is 1:1-10: 1-50.

3. The homogeneous catalyst of claim 1, wherein: the AlR₃The alkyl aluminum cocatalyst is triisobutyl aluminum; the supported titanium catalyst is TiCl₄/MgCl₂。

4. The homogeneous catalyst of claim 1, wherein: the preparation method of the homogeneous catalyst comprises the following steps of proportionally mixing the supported titanium catalyst and AlR under the protection of nitrogen₃And (3) sequentially adding the alkyl aluminum cocatalyst and the polyisoprene polymer into a reaction vessel, and reacting at 0-60 ℃ for 10-240min to obtain the homogeneous catalyst.

5. A process for preparing trans-1, 4-polyisoprene polymer using the homogeneous catalyst as claimed in any one of claims 1 to 4, wherein: adding isoprene under the protection of nitrogen, adding AlR according to any one of claims 1-4₃An alkyl aluminum cocatalyst, reacting for 0.5-2h at-10-25 ℃, then adding the homogeneous catalyst of any one of claims 1-4, reacting for 0.5-72h at-10-25 ℃, and terminating the reaction to obtain the trans-1, 4-polyisoprene polymer.

6. Use of the method of claim 5; terminating the polymerization reaction by using ethanol, standing and settling, and drying in vacuum to obtain the trans-1, 4-polyisoprene polymer.

Technical Field

The invention relates to a catalyst for synthesizing trans-1, 4-polyisoprene polymer, in particular to a homogeneous catalyst for preparing the trans-1, 4-polyisoprene polymer, a preparation method and application thereof.

Background

Trans-1, 4-polyisoprene is a crystalline material, shows the performance of high modulus and high tensile strength, the polymerization mode of trans-1, 4-polyisoprene usually has solution polymerization and bulk polymerization at present, solution polymerization is convenient for heat transfer and production process regulation and control, but the solvent content in the reaction system is as high as 90%, directly leads to long post-treatment process, more devices, high energy consumption, and brings about many environmental protection and pressure in the aspect of safety. Although the bulk polymerization can perfectly make up for the defects of long flow, multiple devices, high energy consumption and the like of solution polymerization, the polymerization reaction is generally carried out under the anaerobic condition, a supported titanium catalyst and aluminum alkyl are sequentially added into isoprene, constant-temperature stirring polymerization is carried out, methanol or ethanol is used as a terminator, the catalyst is a commonly used supported solid catalyst, the phase state of the supported catalyst is solid, the polymerization reaction process is solid-liquid two-phase polymerization, the dispersion is difficult in industrial production, the reaction progress is difficult to control, and the performance and the uniformity of a polymer are directly influenced. In view of the above, the invention provides a homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer, a preparation method and an application thereof, wherein the catalyst is a titanium homogeneous catalyst, and a homogeneous bulk polymerization method is adopted at the early stage of polymerization reaction, so that the technical problems of uneven polymerization and difficult regulation and control of the production process in the existing polymerization reaction are solved.

Disclosure of Invention

In order to solve the technical problems of uneven polymerization and difficult regulation and control of the production process of the polymerization reaction in the prior art, the invention provides a homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer.

The traditional Ti series catalyst is powder, and during the polymerization use process, the powder Ti and the alkyl aluminum are directly added into the isoprene for polymerization, or the powder Ti and the alkyl aluminum are mixed for reaction and then added into the isoprene for polymerization. The powder Ti is mixed with the alkyl aluminum to obtain the liquid catalyst containing the precipitate, and the liquid catalyst is still solid powder when directly used, so that the polymerization reaction process is solid-liquid two-phase polymerization.

In order to solve the technical problems, the invention adopts the following technical scheme:

the homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer includes supported titanium catalyst, AlR₃An alkylaluminum cocatalyst and a polyisoprene polymer; wherein, the AlR₃R in the alkylaluminum cocatalyst is C₁-C₆The number average molecular weight of the polyisoprene polymer is 1000-10000, and the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is not less than 30%.

According to the invention, through introducing the polymer of the key component isoprene, the mass fraction of cis-1, 4-polyisoprene in the polymer is not less than 30%, the prepared catalyst can be ensured to be fully dissolved in polyisoprene, and the polymer of isoprene with low molecular weight and low viscosity can perform coordination reaction on the supported titanium catalyst, so that the phase state of the supported titanium catalyst is changed from a solid phase to a liquid phase, and the liquid phase homogeneous catalyst with low viscosity and capable of being dissolved in isoprene is obtained.

Preferably, the supported titanium catalyst and AlR₃The molar ratio of the alkylaluminum cocatalyst to the polyisoprene polymer is 1:1-10: 1-50. Meanwhile, the dosage of the low-molecular-weight and low-viscosity isoprene polymer is strictly controlled, when the dosage is too low, the isoprene polymer cannot be coordinated with all Ti to generate a new catalyst, when the dosage is too high, the increase of the amount of the polymer coordinated with the Ti influences the viscosity of the catalyst, and when the viscosity of the catalyst is too high, the dispersion of the catalyst in the later polymerization process is influenced, so that the purposes of controlling polymerization and product stability cannot be achieved.

More preferably, the AlR₃The alkyl aluminum cocatalyst is triisobutyl aluminum; the supported titanium catalyst is TiCl₄/MgCl₂。

The invention also provides a preparation method of the homogeneous catalyst, and the supported titanium catalyst and the AlR are proportionally mixed under the protection of nitrogen gas₃And (3) sequentially adding the alkyl aluminum cocatalyst and the polyisoprene polymer into a reaction vessel, and reacting at 0-60 ℃ for 10-240min to obtain the homogeneous catalyst.

Another object of the present invention is to provide a method for preparing trans-1, 4-polyisoprene polymer using the above homogeneous catalyst, which comprises adding isoprene and AlR under nitrogen protection₃The alkyl aluminum cocatalyst reacts for 0.5 to 2 hours at the temperature of between 10 ℃ below zero and 25 ℃, then the homogeneous catalyst of claim 1 is added to react for 0.5 to 72 hours at the temperature of between 10 ℃ below zero and 25 ℃, and the reaction is stopped to obtain the trans-1, 4-polyisoprene polymer.

At the beginning of the reaction, isoprene was added first, and AlR₃The alkyl aluminum cocatalyst is reacted for a time sufficient to allow AlR₃Can be completely completed with micro water, micro oxygen and other impurities in isoprene, ensures the cleanliness of a system, further ensures the control of the catalytic efficiency after the homogeneous catalyst is added and the product indexes such as the molecular weight, the distribution, the Mooney and the like of the product, and also aims to obtain a product with narrower and more controllable molecular weight distribution.

Preferably, ethanol is used for terminating the polymerization reaction, and after standing and settling, the trans-1, 4-polyisoprene polymer is obtained by vacuum drying.

Firstly, the homogeneous catalyst provided by the invention is used for polymerization reaction, and can improve the catalytic effect of the catalyst and the polymerization efficiency of the polymerization reaction. The solid catalyst or the two-phase catalyst containing the precipitate cannot be uniformly distributed in the polymerization production process, so that the active center of the catalyst is partially agglomerated and cannot exert the maximum effect of the catalyst. The solid catalyst or the two-phase catalyst containing the precipitate is easy to adhere and remain on the wall of a polymerization kettle in the polymerization production process, so that a large part of the catalyst cannot be uniformly dispersed in a polymerization solution, the efficiency of the catalyst is greatly reduced, and the production loss is increased.

Secondly, the homogeneous catalyst of the invention can reduce the difficulty of conveying and metering materials in production. The traditional catalyst is light solid powder or two-phase liquid containing precipitate, requires inert environment protection in the conveying and metering processes, and has high difficulty in actual conveying and metering of production. The light solid powder cannot be metered on line, and only can be metered and added manually, so that the production efficiency is greatly reduced, and meanwhile, because the catalyst reacts violently in water, air and oxygen, the manual operation brings great danger and inconvenience; although the two-phase liquid containing the precipitate can be conveyed and metered on line by using mechanical equipment, the uniformity of the conveyed and metered catalyst is difficult to ensure due to the precipitate, and the polymerization control, the product index and the stability control of the product are influenced. The homogeneous phase low viscosity catalyst of the invention can realize accurate and stable on-line conveying, and ensures the stability of the catalyst, thereby ensuring the stable control of polymerization and the stable control of products. The traditional catalyst causes molecules to agglomerate on the kettle wall to form gel due to the attachment of the kettle wall, thereby bringing great instability to products. In the operation and maintenance of actual production equipment, the maintenance frequency of a polymerization kettle is reduced under the condition of using a homogeneous catalyst, so that the production efficiency is improved.

The invention provides a homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer, a preparation method thereof and a homogeneous bulk polymerization method, wherein a polymer of isoprene with low molecular weight and low viscosity as a key component is introduced to perform coordination reaction on a supported titanium catalyst, so that the phase state of the supported titanium catalyst is changed from a solid phase to a liquid phase. According to the technical scheme, compared with solution polymerization, the polymerization reaction provided by the invention uses a bulk polymerization process, has no solvent, can avoid the problems of long post-treatment process, more devices, high energy consumption and the like, does not need post-treatment and monomer solvent recovery processes, and has the advantages of simple process flow, high production efficiency, low cost and no three-waste pollution; compared with the traditional titanium bulk polymerization, the catalyst prepared by the invention is liquid phase rather than solid, so that the problems of nonuniform polymerization, difficult control of polymerization reaction, large difference of product technical indexes and the like caused by difficult dispersion of solid in industrial production and polymerization processes are avoided.

Detailed Description

The invention discloses a homogeneous catalyst for preparing trans-1, 4-polyisoprene polymer, a preparation method and application thereof, and can be realized by appropriately improving process parameters by a person skilled in the art by referring to the content. It is expressly intended that all such similar substitutes and modifications which would be obvious to those skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The following detailed description of the invention refers to specific embodiments thereof for better understanding by those skilled in the art.

EXAMPLE 1 preparation of homogeneous catalyst

Under the protection of nitrogen, a supported titanium catalyst TiCl with the molar ratio of 1:1:1 is added₄/MgCl₂、AlR₃Sequentially adding an alkyl aluminum cocatalyst tripropyl aluminum and a polyisoprene polymer into a reaction vessel, and reacting at 0 ℃ for 240min to obtain a homogeneous catalyst; the number average molecular weight of the polyisoprene polymer is 1000, the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is 35%, and the room temperature viscosity of the obtained homogeneous catalyst is 10 pa.s.

EXAMPLE 2 preparation of homogeneous catalyst

Under the protection of nitrogen, a supported titanium catalyst TiCl with the molar ratio of 1:10:50 is added₄/MgCl₂、AlR₃Sequentially adding an alkyl aluminum cocatalyst, namely triethyl aluminum and a polyisoprene polymer into a reaction vessel, and reacting at 60 ℃ for 10min to obtain a homogeneous catalyst; the number average molecular weight of the polyisoprene polymer is 10000, the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is 60%, and the room temperature viscosity of the obtained homogeneous catalyst is 105pa.

EXAMPLE 3 preparation of homogeneous catalyst

Under the protection of nitrogen, a supported titanium catalyst TiCl with the molar ratio of 1:5:25 is added₄/MgCl₂、AlR₃Sequentially adding an alkyl aluminum cocatalyst triisobutyl aluminum and a polyisoprene polymer into a reaction vessel, and reacting at 30 ℃ for 120min to obtain a homogeneous catalyst; the number average molecular weight of the polyisoprene polymer is 5000, the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is 80%, and the room temperature viscosity of the obtained homogeneous catalyst is 45 pa.s.

The homogeneous catalysts prepared in examples 1 to 3 had suitable viscosity, and in the preparation of the homogeneous catalysts, if the amount of polyisoprene polymer added was too low, only a pasty solid mixture containing a large amount of powder could be obtained, and since the amount of isoprene polymer was too low, a liquid phase catalyst could not be obtained at all. If the amount of polyisoprene polymer added is too high, the trans 1, 4 structure content in the product polymer may be less than 98%. If the mass fraction of cis-1, 4-polyisoprene in the polyisoprene polymer is less than 30%, a high-viscosity semisolid catalyst is obtained, and the mixing process is difficult to carry out; when the mass fraction of cis-1, 4-polyisoprene is less than 30%, the remaining structure may be either trans-1, 4 structure or 3, 4 structure, and neither structure can synthesize liquid-phase catalyst, so that the fluidity is not affected.

EXAMPLE 4 Synthesis of trans-1, 4-polyisoprene Polymer

Adding isoprene and adding AlR under the protection of nitrogen₃Alkyl radicalAn aluminum cocatalyst triisobutylaluminum reacts for 1 hour at 15 ℃, then the homogeneous catalyst prepared in the embodiment 3 is added to react for 36 hours at 10 ℃, ethanol is adopted to terminate the polymerization reaction, the mixture is stood for settling and then is dried in vacuum to obtain the trans-1, 4-polyisoprene polymer, the content of the trans-1, 4-polyisoprene polymer in the obtained product polymer is 99 percent, the molecular weight distribution of the product polymer is 3.5, and the catalytic efficiency is 50000g/1 gTi.

The homogeneous catalyst prepared in the example 3 is in a liquid homogeneous state, no precipitation phenomenon occurs, the homogeneous catalyst can be rapidly and uniformly distributed in a polymerization liquid in the polymerization process, no adhesion and agglomeration phenomenon is formed in the kettle wall, and the conveying and metering of materials in the process are easy to realize.

EXAMPLE 5 preparation of trans-1, 4-Polyisoprene Polymer

Adding isoprene and adding AlR under the protection of nitrogen₃An alkyl aluminum cocatalyst, namely triethyl aluminum, is reacted for 2 hours at the temperature of minus 10 ℃, then the homogeneous catalyst prepared in the embodiment 2 is added, the reaction is carried out for 72 hours at the temperature of minus 10 ℃, ethanol is adopted to terminate the polymerization reaction, the reaction product is stood for settling and then is dried in vacuum to obtain the trans-1, 4-polyisoprene polymer, the content of the trans-1, 4-polyisoprene polymer in the obtained product polymer is 98 percent, the molecular weight distribution of the product polymer is 3.2, and the catalytic efficiency is 58000g/1 gTi.

The homogeneous catalyst prepared in the example 2 is in a liquid homogeneous state, no precipitation phenomenon occurs, the homogeneous catalyst can be rapidly and uniformly distributed in a polymerization liquid in the polymerization process, no adhesion and agglomeration phenomenon is formed in the kettle wall, and the conveying and metering of materials in the process are easy to realize.

EXAMPLE 6 preparation of trans-1, 4-Polyisoprene Polymer

Adding isoprene and adding AlR under the protection of nitrogen₃An alkyl aluminum cocatalyst tripropyl aluminum reacts for 0.5h at 25 ℃, then the homogeneous catalyst prepared in the embodiment 2 is added to react for 0.5h at-10 ℃, ethanol is adopted to terminate the polymerization reaction, the mixture is kept stand and settled and then dried in vacuum to obtain the trans-1, 4-polyisoprene polymer, the content of the trans-1, 4-polyisoprene polymer in the obtained product polymer is 99 percent, and the product is producedThe molecular weight distribution of the polymer was 3.6, and the catalytic efficiency was 28000g/1 gTi.

The homogeneous catalyst prepared in the example 2 is in a liquid homogeneous state, no precipitation phenomenon occurs, the homogeneous catalyst can be rapidly and uniformly distributed in a polymerization liquid in the polymerization process, no adhesion and agglomeration phenomenon is formed in the kettle wall, and the conveying and metering of materials in the process are easy to realize.

Comparative example 1

Under the protection of nitrogen, adding isoprene, and adding supported titanium catalyst TiCl4/MgCl with the molar ratio of 1:5₂And AlR₃And (2) reacting triisobutylaluminum serving as an alkyl aluminum cocatalyst for 36 hours at 10 ℃, terminating the polymerization reaction by using ethanol, standing for settling, and drying in vacuum to obtain the trans-1, 4-polyisoprene polymer. The content of trans-1, 4-polyisoprene polymer in the obtained product polymer is 98%, the molecular weight distribution of the product polymer is 5.7, and the catalytic efficiency is 3000g/1 gTi.

Supported titanium catalyst TiCl_4/MgCl₂The catalyst is solid powder, the AlR3 alkyl aluminum cocatalyst is liquid, the AlR3 alkyl aluminum cocatalyst and the liquid can be sequentially blended to form a two-phase state of supernatant and lower-layer sediment, the catalyst still keeps sediment particles in a polymerization liquid in the polymerization process, the solution cannot be rapidly and uniformly distributed in the polymerization liquid, the adhesion and agglomeration phenomena are formed in the kettle wall, even the gelation phenomenon occurs, and the conveying and metering of materials are difficult in the process.

Comparative example 2

Adding isoprene and adding AlR under the protection of nitrogen₃Triisobutylaluminum as alkyl aluminum cocatalyst is reacted for 1h at 15 ℃, and then supported titanium catalyst TiCl with the molar ratio of 1:5 is added₄/MgCl₂And AlR₃And (2) reacting triisobutylaluminum serving as an alkyl aluminum cocatalyst for 36 hours at 10 ℃, terminating the polymerization reaction by using ethanol, standing for settling, and drying in vacuum to obtain the trans-1, 4-polyisoprene polymer. The content of trans-1, 4-polyisoprene polymer in the obtained product polymer is 98%, the molecular weight distribution of the product polymer is 5.0, and the catalytic efficiency is 3600g/1 gTi.

Supported titanium catalyst TiCl₄/MgCl₂And AlR₃The alkyl aluminum cocatalyst is in a two-phase liquid shape, precipitation occurs, the catalyst cannot be dissolved in polymerization liquid and cannot be rapidly and uniformly distributed in the polymerization process, adhesion and agglomeration phenomena are formed in the kettle wall, and the conveying and metering of materials are difficult in the process.

From the catalytic results of comparative examples 1 and 2, whether or not AlR was added prior to the reaction₃The molecular weight distribution and the catalytic efficiency of the finally obtained polymer are not ideal when the alkyl aluminum cocatalyst is used for purification treatment.

Comparative example 3

Under the protection of nitrogen, the homogeneous catalyst prepared in example 3 was added, the reaction was carried out for 36 hours at 10 ℃, ethanol was used to terminate the polymerization reaction, and after standing and settling, the polymer was vacuum-dried to obtain a trans-1, 4-polyisoprene polymer, wherein the content of the trans-1, 4-polyisoprene polymer in the obtained polymer product was 98%, the molecular weight distribution of the polymer product was 4.6, and the catalytic efficiency was 49000g/1 gTi.

Comparative example 3 no AlR addition prior to reaction₃The aluminum alkyl cocatalyst is used for purification treatment, which has little influence on the catalytic efficiency of the catalyst, but can influence the molecular weight distribution of the final product polymer.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.