An external electron donor, an olefin polymerization catalyst comprising the same, and a method of olefin polymerization

Abstract

The present disclosure relates to an external electron donor, an olefin polymerization catalyst comprising the same and a method of olefin polymerization, the external electron donor having a structure shown in Formula I, wherein A, B and D are the same or different, and are each independently selected from C1-C10 alkoxy, C1-C10 alkylamino; R1 is selected from C4-C30 bridged cycloalkyl, C3-C30 bridged cycloalkyl containing N atom and / or P atom. The external electron donor of the present disclosure can improve the hydrogen response sensitivity of the catalyst, and has a wide spectrum of applicability. Formula I.

Description

Technical Field

[0001] This disclosure relates to the field of Fischer-Tropsch synthesis, and more particularly to an external electron donor, an olefin polymerization catalyst comprising the external electron donor, and a method for olefin polymerization. Background Technology

[0002] The catalytic polymerization (or copolymerization) of propylene using olefin polymerization catalysts is the result of the combined action of three parts: the main catalyst, the co-catalyst alkylaluminum, and the external electron donor. The main catalyst consists of a magnesium chloride support, an internal electron donor compound, and a titanium compound. The internal electron donor compound not only improves the catalyst's activity but also enhances its stereotactic properties. To date, various compounds such as diisobutyl phthalate, ethyl benzoate, succinate, glycol esters, diethers, 1,2-phenylene aromatic diesters, amides, or amide esters have been widely used as internal electron donors in the preparation of olefin polymerization catalysts, and have significantly improved the performance of Ziegler-Natta main catalysts. However, these main catalysts still have drawbacks in practical industrial applications, such as insufficient hydrogen sensitivity and inadequate product isotacticity.

[0003] Researchers from numerous enterprises and research institutions are dedicated to developing various novel external electron donors to address the aforementioned problems. Among these external electron donors, organosilanes are favored by industry due to their low toxicity, low cost, and excellent performance control. Based on continuous research in this area, a series of high-performance organosilane external electron donors have been successfully developed, such as T-Donor, C-Donor, D-Donor, B-Donor, and P-Donor. However, with the increasing market demand for high-flow products, the currently used external electron donors still have certain limitations, such as insufficient hydrogen sensitivity, which is unfavorable for producing high-flow polyolefin grades; secondly, the universality of various external electron donors for different main catalysts is still insufficient. Therefore, developing a new external electron donor that can overcome the above-mentioned defects of existing technologies for olefin polymerization is of great significance. Summary of the Invention

[0004] The purpose of this disclosure is to provide an external electron donor, an olefin polymerization catalyst comprising the external electron donor, and a method for olefin polymerization.

[0005] To achieve the above objectives, a first aspect of this disclosure provides an external electron donor for an olefin polymerization catalyst, the external electron donor having the structure shown in Formula I:

[0006] Formula I Among them, A, B and D may be the same or different, and are independently selected from C1-C10 alkoxy groups and C1-C10 alkylamino groups, respectively; R1 is selected from bridged cycloalkyl groups of C4-C30, or bridged cycloalkyl groups of C3-C30 containing N and / or P atoms.

[0007] Optionally, R1 is selected from C4-C30 bridged cycloalkyl groups, or C4-C30 bridged cycloalkyl groups containing N atoms and / or P atoms.

[0008] Optionally, R1 is selected from adamantyl, norbornel, azirmonobornel and bicyclo[3.3.3]undecyl.

[0009] Optionally, A, B, and D may be the same or different, and may be independently selected from methoxy, ethoxy, methylamino, and ethylamino, respectively.

[0010] Optionally, the external electron donor is selected from the group consisting of: , , , , , .

[0011] The second aspect of this disclosure provides an olefin polymerization catalyst comprising a main catalyst, a co-catalyst, and an external electron donor, wherein the external electron donor includes the external electron donor described in the first aspect of this disclosure.

[0012] Optionally, the main catalyst includes a magnesium-containing support, an internal electron donor, and a titanium-containing compound; The magnesium-containing carrier includes MgX n (OR2) 2-n One or more of MgCl2·mR2OH, MgCl2 / SiO2, MgCl2 / Al2O3, and mixtures of MgX2 and titanium alkoxides, wherein m is selected from 0.1-6, n is selected from any integer from 0-2, X is selected from halogens, and R2 is selected from hydrogen and C1-C8 alkane groups; The internal electron donor includes one or more of the following: n-butyl phthalate, isobutyl phthalate, 9,9-bis(methoxymethyl)fluorene, and 3-methyl-5-tert-butylcatechol benzoate. The chemical formula of the titanium-containing compound is TiX. p (OR3) 4-p Where R3 is selected from C1-C20 alkane groups, X is selected from halogens, and p is selected from any integer from 1 to 4; Optionally, the cocatalyst comprises an organoaluminum compound with the chemical formula Al(R4). q X (3-q)Organoaluminum compounds, wherein R4 is selected from hydrogen, C1-C20 alkane groups, X is selected from halogens, and q is selected from any integer from 1 to 3; Preferably, the co-catalyst comprises one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum.

[0013] Optionally, in the olefin polymerization catalyst, the molar ratio of the main catalyst to the co-catalyst is 1:(50-500), the molar ratio of the main catalyst to the external electron donor is 1:(5-100), and the number of moles of the main catalyst is calculated as the total number of moles of the magnesium-containing support, the internal electron donor, and the titanium-containing compound.

[0014] A third aspect of this disclosure provides a method for olefin polymerization, the method comprising: contacting the olefin with a catalyst to carry out an olefin polymerization reaction; the catalyst comprising the olefin polymerization catalyst described in the second aspect of this disclosure.

[0015] Optionally, the olefin has the structural formula CH2=CHR5, where R5 is selected from hydrogen and C1-C12 alkane groups.

[0016] Through the above technical solutions, the polycyclic organosilane with a specific structure disclosed herein, as an external electron donor, can effectively improve the hydrogen sensitivity of the main catalyst, increase the stereoregulation of the catalyst, and effectively improve the melt index of the polyolefin while maintaining its isotacticity. Furthermore, the external electron donor of this disclosure can also regulate the molecular weight distribution of the polyolefin, ensuring that the prepared polyolefin product meets requirements. The external electron donor of this disclosure has broad applicability and is suitable for different internal electron donor catalytic systems.

[0017] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0018] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0019] A first aspect of this disclosure provides an external electron donor for an olefin polymerization catalyst, the external electron donor having a structure shown in Formula I:

[0020] Formula I Among them, A, B and D may be the same or different, and are independently selected from C1-C10 alkoxy groups and C1-C10 alkylamino groups, respectively; R1 is selected from bridged cycloalkyl groups of C4-C30, or bridged cycloalkyl groups of C3-C30 containing N and / or P atoms.

[0021] The inventors of this disclosure unexpectedly discovered that using polycyclic organosilanes with specific structures as external electron donors can effectively improve the hydrogen sensitivity of the main catalyst, increase the stereoregulation of the catalyst, effectively improve the melt index of polyolefins while maintaining their isotacticity, and also regulate the molecular weight distribution of polyolefins, enabling the prepared polyolefin products to meet requirements. The external electron donors disclosed herein have broad applicability and are suitable for different internal electron donor catalytic systems.

[0022] In this disclosure, "bridged cycloalkyl" refers to a group formed by the loss of one hydrogen atom from a bridged cycloalkane. Bridged cycloalkyl groups can contain two, three, or four rings, and the number of carbon atoms in a bridged cycloalkyl group can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. In some embodiments, the bridged cycloalkyl group is a C4-C20 bridged cycloalkyl group; in other embodiments, the bridged cycloalkyl group is a C6-C12 bridged cycloalkyl group. The number of carbon atoms in the "bridged cycloalkyl group containing N and / or P atoms" can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30. In some embodiments, the bridged cycloalkyl group containing N and / or P atoms is a C4-C20 bridged cycloalkyl group containing N and / or P atoms. In other embodiments, the bridged cycloalkyl group containing N and / or P atoms is a C6-C12 bridged cycloalkyl group containing N and / or P atoms.

[0023] According to one embodiment of this disclosure, R1 is selected from C4-C30 bridged cycloalkyl groups and C4-C30 bridged cycloalkyl groups containing N atoms and / or P atoms.

[0024] According to one specific embodiment of this disclosure, R1 is selected from adamantyl alkyl ( ), norborneol alkyl ), azirmonoborneol ( ) and bicyclic [3.3.3]undecyl ( ).

[0025] In this disclosure, "alkoxy" is generally used The symbol indicates that R represents an alkyl group, and the number of carbon atoms in the alkoxy group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, including but not limited to methoxy, ethoxy, and propoxy groups.

[0026] In this disclosure, "alkylamino" refers to In this , R represents an alkyl group, and the number of carbon atoms in the alkylamino group can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, including but not limited to methylamino, ethylamino, and propylamino.

[0027] According to one embodiment of this disclosure, A, B, and D may be the same or different, and are independently selected from C1-C6 alkoxy groups and C1-C6 alkylamino groups, respectively.

[0028] According to one specific embodiment of this disclosure, A, B, and D may be the same or different, and are each independently selected from methoxy ( ), ethoxy ( ), methylamino ( ) and ethylamino ( ).

[0029] In this disclosure, It refers to the chemical bond that connects with other groups.

[0030] According to one specific embodiment of this disclosure, the external electron donor is selected from the group consisting of: , , , , , .

[0031] According to one embodiment of this disclosure, the external electron donor of this disclosure can be prepared by conventional steps.

[0032] The second aspect of this disclosure provides an olefin polymerization catalyst comprising a main catalyst, a co-catalyst, and an external electron donor, wherein the external electron donor includes the external electron donor described in the first aspect of this disclosure.

[0033] According to one embodiment of this disclosure, the main catalyst comprises a magnesium-containing support, an internal electron donor, and a titanium-containing compound, wherein the ratio of the magnesium-containing support, the internal electron donor, and the titanium-containing compound is conventional in the art; for example, the magnesium-containing support comprises MgX. n (OR2) 2-n The titanium-containing compound comprises one or more of the following: MgCl2·mR2OH, MgCl2 / SiO2, MgCl2 / Al2O3, and a mixture of MgX2 and titanium alkoxides, wherein m is selected from 0.1-6, n is selected from any integer from 0-2, X is selected from halogens, and R2 is selected from one or more of hydrogen and C1-C8 alkane groups; the internal electron donor comprises one or more of n-butyl phthalate, isobutyl phthalate, 9,9-bis(methoxymethyl)fluorene, and 3-methyl-5-tert-butylcatechol benzoate; the chemical formula of the titanium-containing compound is TiX. p (OR3)4-p In this context, R3 is selected from alkane groups of C1-C20, X is selected from halogens, and p is selected from any integer from 1 to 4.

[0034] According to one embodiment of this disclosure, the main catalyst can be commercially available or prepared by conventional procedures.

[0035] According to one embodiment of this disclosure, the type of cocatalyst is conventional in the art; for example, the cocatalyst includes an organoaluminum compound with the chemical formula Al(R4). q X (3-q) The organoaluminum compound, wherein R4 is selected from hydrogen, C1-C20 alkane group, X is selected from halogen, and q is selected from any integer from 1 to 3; preferably, the co-catalyst includes trialkylaluminum, more preferably one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum and tri-n-octylaluminum.

[0036] In this disclosure, "alkane group" refers to a group formed by losing one hydrogen atom from an alkane. The number of carbon atoms in a "C1-C20 alkane group" can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20, including but not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-hexyl, and n-octyl. The number of carbon atoms in a "C1-C12 alkane group" can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. The number of carbon atoms in a "C1-C8 alkane group" can be 1, 2, 3, 4, 5, 6, 7, or 8.

[0037] According to one embodiment of this disclosure, in the olefin polymerization catalyst, the molar ratio of the main catalyst to the co-catalyst is 1:(50-500), preferably 1:(50-200), including but not limited to 1:50, 1:80, 1:100, 1:120, 1:150, 1:180, 1:200, or any combination thereof; the molar ratio of the main catalyst to the external electron donor is 1:(5-100), preferably 1:(5-50), including but not limited to 1:5, 1:50 ... The molar ratios are 10, 1:12, 1:15, 1:20, 1:25, 1:30, 1:32, 1:35, 1:40, 1:48, 1:50, or any combination thereof, wherein the molar number of the main catalyst is calculated as the total molar number of the magnesium-containing support, the internal electron donor, and the titanium-containing compound; this disclosure, by selecting specific types of main catalysts and co-catalysts and combining them with external electron donors of specific structures of this disclosure, and by limiting the proportions of their use, enables the prepared olefin polymerization catalyst to have good hydrogen-modulated sensitivity.

[0038] According to one embodiment of this disclosure, a method for preparing an olefin polymerization catalyst includes: mixing a main catalyst, a co-catalyst, and an external electron donor, wherein the co-catalyst and the external electron donor can be added in solution form, and the mixing can be carried out at 20-70°C.

[0039] A third aspect of this disclosure provides a method for olefin polymerization, the method comprising: contacting the olefin with a catalyst to carry out an olefin polymerization reaction; the catalyst comprising the olefin polymerization catalyst described in the second aspect of this disclosure.

[0040] According to one embodiment of this disclosure, the olefin has the structural formula CH2=CHR5, where R5 is selected from one or more of hydrogen and C1-C12 alkane groups.

[0041] According to one embodiment of this disclosure, the method includes: adding hydrogen gas to the olefin polymerization reaction, wherein the amount of hydrogen gas used is conventional in the art; and the time, temperature, and other conditions of the olefin polymerization reaction are conventional in the art.

[0042] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. All raw materials used in the examples are commercially available.

[0043] Melt flow rate (MFR) test method: Tested according to ASTM D1238.

[0044] Molecular weight distribution was determined using a PolymerChar high-temperature gel permeation chromatography system (GPC-IR6).

[0045] Test method for catalyst polymerization activity: mass of product obtained per hour per gram of catalyst during polymerization.

[0046] Test method for xylene solubles (XS): The test was performed using the Polymer Char fully automated xylene solubles analyzer (CRYSTEX QC).

[0047] The external electron donors used in the following examples and comparative examples were prepared by conventional methods.

[0048] Examples 1-6 Propylene polymerization was carried out using propylene as a raw material in a 2L stainless steel polymerization reactor. Step 1: First, purge the reactor with purified nitrogen (water <1ppm, oxygen <1ppm); then, sequentially add 0.55L of liquid propylene and 0.2g of hydrogen at room temperature, and heat to 70℃. Step 2: Before the reactor temperature reaches 70°C, 0.75 mL of 1 M triethylaluminum (co-catalyst) heptane solution, 1.1 mL of 0.05 M hexane solution of the external electron donor, and 6 mg of the main catalyst (brand name SAL catalyst, magnesium support is magnesium chloride, internal electron donor is isobutyl phthalate, and titanium compound is titanium tetrachloride) are pre-complexed for 5 min to obtain the olefin polymerization catalyst. When the reactor reaches 70°C, the catalyst is injected into the reactor to start the reaction time.

[0049] In olefin polymerization catalysts, the molar ratio of main catalyst, co-catalyst and external electron donor is 1:200:15, and the molar number of the main catalyst is the total molar number of magnesium chloride, isobutyl phthalate and titanium tetrachloride. Step 3: After reacting for 60 minutes, vent the material, cool down, and stop the reaction. The polypropylene product was then removed and vacuum dried at 30°C for 2 hours. The resulting polypropylene product was tested for melt index, isotacticity, molecular weight distribution, and polymerization activity. The structure of the external electron donor and the reaction parameters are listed in Table 1.

[0050] Example 7 Preparation of main catalyst C1: In a 250 mL reactor with a stirrer and a custom-made 6-port filter, after complete nitrogen purging, 2.2 g of magnesium diethoxy and 50 mL of chlorobenzene were added. Then, 100 mL of titanium tetrachloride / chlorobenzene solution (volume ratio 1:1) was added dropwise while maintaining the temperature at -10 °C. The system was then slowly heated to 90 °C. At this point, 1.5 g of the internal electron donor 9,9-bis(methoxymethyl)fluorene (CAS: 182121-12-6) dissolved in chlorobenzene was injected into the reactor using a syringe. The system was then heated to 110 °C and held at this temperature for 1 h. The mother liquor was then filtered clean, and 100 mL of titanium tetrachloride / chlorobenzene solution (volume ratio 1:1) was added dropwise. The mixture was reacted at a constant temperature of 1:1 (1:1 ratio) for 1 hour at 110°C. The resulting mother liquor was then filtered clean. Finally, 100 mL of titanium tetrachloride / chlorobenzene solution (volume ratio 1:1) was added dropwise, and the mixture was reacted at a constant temperature of 110°C for 0.5 hours. The resulting mother liquor was then filtered clean, and the solid was washed with 100 mL of n-heptane. The washing was repeated three times. The n-heptane was filtered off, and the product was dried to obtain a solid powder, which is the main catalyst C1. The magnesium support is magnesium chloride, the internal electron donor is 9,9-bis(methoxymethyl)fluorene, and the titanium compound is titanium tetrachloride. In the main catalyst C1, the titanium content is 3.2 wt%, and the content of the internal electron donor 9,9-bis(methoxymethyl)fluorene is 16.2 wt%.

[0051] The propylene polymerization reaction was carried out using the method of Example 1, except that the SAL catalyst was replaced with an equimolar amount of the main catalyst C1. The structure of the external electron donor and the reaction result parameters are listed in Table 1.

[0052] Example 8 The propylene polymerization reaction was carried out using the method of Example 1, except that the SAL catalyst was replaced with an equimolar main catalyst (brand name C702, magnesium support is magnesium chloride, internal electron donor is 3-methyl-5-tert-butylcatechol benzoate, titanium compound is titanium tetrachloride, and titanium content is 3.2% by weight). The structure of the external electron donor and the reaction result parameters are listed in Table 1.

[0053] Comparative Examples 1-2 The propylene polymerization reaction was carried out using the method of Example 1, except that an external electron donor was used as shown in Table 1; the reaction result parameters are listed in Table 1.

[0054] Comparative Example 3 The propylene polymerization reaction was carried out using the method of Example 1, except that an equimolar amount of main catalyst C1 was used instead of the SAL catalyst, and the external electron donors in Table 1 were used; the reaction results parameters are listed in Table 1.

[0055] Comparative Example 4 The propylene polymerization reaction was carried out using the method of Example 1, except that an equimolar amount of the main catalyst C702 was used instead of the SAL catalyst, and the external electron donors in Table 1 were used; the reaction results parameters are listed in Table 1.

[0056] Table 1

[0057]

[0058] Based on the above data, it can be seen that the external electron donor disclosed herein is applicable to different types of internal electron donors. As an external electron donor for olefin polymerization catalysts, while maintaining good isotacticity, the catalyst exhibits significantly higher hydrogen sensitivity.

[0059] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0060] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. An external electron donor for an olefin polymerization catalyst, characterized in that, The external electron donor has the structure shown in Formula I: Formula I Among them, A, B and D may be the same or different, and are independently selected from C1-C10 alkoxy groups and C1-C10 alkylamino groups, respectively; R1 is selected from bridged cycloalkyl groups of C4-C30, or bridged cycloalkyl groups of C3-C30 containing N and / or P atoms.

2. The external electron donor according to claim 1, wherein, R1 is selected from C4-C30 bridged cycloalkyl groups, or C4-C30 bridged cycloalkyl groups containing N and / or P atoms.

3. The external electron donor according to claim 1, wherein, R1 is selected from adamantyl, norbornel, azanorbornel, and bicyclo[3.3.3]undecyl.

4. The external electron donor according to claim 1, wherein, A, B, and D may be the same or different, and are independently selected from methoxy, ethoxy, methylamino, and ethylamino, respectively.

5. The external electron donor according to claim 1, wherein, The external electron donor is selected from the group consisting of the following compounds: 、 、 、 、 、 。 6. An olefin polymerization catalyst, comprising a main catalyst, a co-catalyst, and an external electron donor, characterized in that, The external electron donor includes the external electron donor as described in any one of claims 1-5.

7. The olefin polymerization catalyst according to claim 6, wherein, The main catalyst includes a magnesium-containing support, an internal electron donor, and a titanium-containing compound; The magnesium-containing carrier includes MgX n (OR2) 2-n One or more of MgCl2·mR2OH, MgCl2 / SiO2, MgCl2 / Al2O3, and mixtures of MgX2 and titanium alkoxides, wherein m is selected from 0.1-6, n is selected from any integer from 0-2, X is selected from halogens, and R2 is selected from hydrogen and C1-C8 alkane groups; The internal electron donor includes one or more of the following: n-butyl phthalate, isobutyl phthalate, 9,9-bis(methoxymethyl)fluorene, and 3-methyl-5-tert-butylcatechol benzoate. The chemical formula of the titanium-containing compound is TiX. p (OR3) 4-p Where R3 is selected from C1-C20 alkane groups, X is selected from halogens, and p is selected from any integer from 1 to 4; Optionally, the cocatalyst comprises an organoaluminum compound with the chemical formula Al(R4). q X (3-q) Organoaluminum compounds, wherein R4 is selected from hydrogen, C1-C20 alkane groups, X is selected from halogens, and q is selected from any integer from 1 to 3; Preferably, the co-catalyst comprises one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and tri-n-octylaluminum.

8. The olefin polymerization catalyst according to claim 7, wherein, In the olefin polymerization catalyst, the molar ratio of the main catalyst to the co-catalyst is 1:(50-500), the molar ratio of the main catalyst to the external electron donor is 1:(5-100), and the number of moles of the main catalyst is calculated as the total number of moles of the magnesium-containing support, the internal electron donor, and the titanium-containing compound.

9. A method for olefin polymerization, the method comprising: The olefin is contacted with a catalyst to carry out an olefin polymerization reaction; characterized in that the catalyst comprises the olefin polymerization catalyst according to any one of claims 6-8.

10. The method according to claim 9, wherein, The olefin has the structural formula CH2=CHR5, where R5 is selected from hydrogen and C1-C12 alkane groups.

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