A vanadium catalyst system and its preparation method and application

Abstract

The invention relates to the technical field of catalysts for synthesizing ethylene-propylene rubber, and in particular to a vanadium catalyst system and a preparation method and application thereof. The vanadium catalyst system comprises a main catalyst and a co-catalyst, wherein the main catalyst is formed by the coordination of a vanadium compound and an organic phosphine compound; the vanadium compound is VO(OR)3, V(acac)3, VO(OR)2Cl, VO(OR)Cl2, VCl4, VOCl3 or a vanadium complex, and the ligand of the vanadium complex is a fatty alcohol, an amine, a phosphate, octahydroxyquinoline or an oxime; the organic phosphine compound has the structural formula: PR3 or P(Ph-OR1)3, where R is C1 to C 20 One of alkyl, phenyl, and substituted phenyl; R1 is C1~C 20 The vanadium catalyst system has enhanced stability to water, air and oxygen. When used for copolymerization of ethylene and propylene, the reaction activity is high, and the ethylene content in the obtained ethylene-propylene rubber binary copolymer can be adjusted to 50wt% to 70wt%, and the ENB content in the ternary copolymer can be adjusted from 0.80wt% to 10.57wt%, and the structure is controllable.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts for synthesizing ethylene-propylene rubber, and in particular to a vanadium catalyst system and a preparation method and application thereof. Background Art

[0002] Ethylene propylene rubber is a copolymer rubber with ethylene and propylene as basic monomers. It can be specifically divided into EPDM and EPDM. Compared with other rubber varieties, EPDM has the following advantages: 1. It does not contain double bonds in the main chain, is fully saturated, and is resistant to ozone, aging, chemicals and high temperatures; 2. It has a light specific gravity; 3. It has excellent insulation properties; 4. It is a rubber variety that can be highly oil-filled. EPDM is one of the most promising types of rubber. Since its commercial production, its application field has been continuously expanded. It has been widely used in automotive parts, building materials, wires and cables, heat-resistant hoses, advanced sealing materials, lubricant additives and polyolefin modification.

[0003] The production of EPDM rubber at home and abroad mostly uses vanadium compounds as the main catalyst, and organic aluminum compounds and activation promoters as co-catalysts. Among them, these vanadium compounds used as the main catalyst are VX3, VX4, VOX3 and VO(OR) 3-n X n , X is a halogen, mainly a chlorine atom, R is an alkyl group of 6 to 12 carbon atoms, and n is an integer of 0 to 2. Among them, VOCl3 is the most commonly used catalyst in industry, which is prepared by high-temperature chlorination of V2O5. The large-scale use of chlorine not only harms the health of operators, but also causes serious environmental pollution. On the other hand, VOCl3 is very sensitive to water and oxygen. A very small amount of water can react with it to decompose the catalyst and generate hydrogen chloride gas and reddish-brown dust of vanadium pentoxide, which is extremely harmful to the human body and also limits the application of such catalysts. The inventor team is committed to the research on the preparation technology and application technology of vanadium-based catalysts, adopts green preparation technology, avoids the high-temperature chlorination preparation process of the above-mentioned vanadium compounds, solves the problem of water and oxygen instability of vanadium catalysts, and improves the polymerization activity of vanadium catalysts (Chinese patents ZL201410182308.2, ZL 201210496187.X, ZL 201210330503.6). Although the above invention effectively improves the disadvantages of low activity and rapid deactivation of traditional vanadium catalysts such as VOCl3 at high temperature, the problem of how to regulate the microstructure of EPDM and the insertion rate of comonomers has not been solved. Therefore, the technical problem solved by the present invention is to regulate the electron cloud density and steric hindrance of the active center of the vanadium catalyst by designing and selecting the structure of the organic phosphine compound, regulate the ethylene unit content in the EPDM or the insertion rate of the third monomer in the EPDM, and reduce the formation of gel in the polymerization process of the EPDM, so as to enhance the ability of random copolymerization of ethylene and propylene. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present invention provides a vanadium catalyst system and a preparation method and application thereof. The vanadium catalyst system is formed by combining a vanadium compound with an organic phosphine compound. The addition of the organic phosphine compound enhances the electron cloud density of the vanadium active center and improves the life of the active center; at the same time, the ability to regulate the insertion rate of the comonomer is increased to prepare an ethylene-propylene rubber with a controllable structure; and the disadvantages of the traditional vanadium catalyst preparation process being complicated, unsuitable for existing industrial production equipment, and having low practicality are avoided.

[0005] To achieve the above object, the technical solution of the present invention is: a vanadium catalyst system, comprising a main catalyst and a co-catalyst, wherein the main catalyst is formed by a combination of a vanadium compound and an organic phosphine compound;

[0006] The vanadium compound is at least one of VO(OR)3, V(acac)3, VO(OR)2Cl, VO(OR)Cl2, VCl4, VOCl3 and vanadium complexes;

[0007] The ligand of the vanadium complex is at least one of fatty alcohols, amines, phosphates, octahydroxyquinoline and oximes;

[0008] The co-catalyst includes an organoaluminum compound.

[0009] Further, the organic phosphine compound includes at least one of structural formula I and structural formula II;

[0010]

[0011]

[0012] Among them, the structural formula of structural formula I is: PR3, R is C1~C 20 One of alkyl, phenyl, and substituted phenyl; the structural formula of structural formula II is: P(Ph-OR1)3, R1 is C1~C 20 of alkyl.

[0013] In the present invention, the vanadium catalyst system comprises a main catalyst and a co-catalyst, wherein the main catalyst is formed by a vanadium compound and an organic phosphine compound. The electron pair of the organic phosphine compound can coordinate with pentavalent vanadium to protect the pentavalent vanadium.

[0014] Furthermore, the organoaluminum compound is at least one of triethylaluminum trichloride, ethylaluminum dichloride, diethylaluminum monochloride and isobutylaluminum dichloride.

[0015] Furthermore, the co-catalyst also includes an activation promoter, and the activation promoter is a halogenated alkane or an ester.

[0016] The co-catalyst is commonly used in the art, and the organoaluminum compound is more preferably one or both of ethylaluminum dichloride and diethylaluminum monochloride. The present invention has no special restrictions on the source of the alkylaluminum compound, which can be purchased from the market. The activation promoter is more preferably ethyl trichloroacetate, CH3Cl, CH2Cl2 or CHCl3; or no activation promoter is used. The present invention does not impose any special restrictions on the usage ratio of the main catalyst and the co-catalyst, and it can be selected according to the routine of those skilled in the art.

[0017] Furthermore, the ratio of the mole number of vanadium in the vanadium compound to the mole number of the organic phosphine compound is 1:1-10.

[0018] Furthermore, the structural formula I is at least one of tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, triphenylphosphine, tri(2,4-xylyl)phosphine, and tri(p-tolyl)phosphine.

[0019] Furthermore, in the structural formula II, R1 is C1 to C 16 of alkyl.

[0020] The present invention also discloses a method for preparing the vanadium catalyst system described in the above technical solution, comprising the following steps:

[0021] S1: mixing a vanadium compound and an organic phosphine compound in an organic solvent to obtain a main catalyst;

[0022] S2: mixing the main catalyst and the co-catalyst to obtain a vanadium catalyst system.

[0023] Furthermore, in the organic solvent solution of the vanadium compound, the organic solution of the organic phosphine compound is slowly added dropwise at 0 to 20°C, and then the reaction is carried out at a temperature of 20 to 70°C for 2 to 40 minutes. After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 35 to 80°C to obtain the main catalyst. In the present invention, the vanadium compound and the organic phosphine compound are first mixed and reacted in an organic solvent to obtain the main catalyst. The ratio of the molar number of vanadium in the vanadium compound to the molar number of the electron donor is preferably 1:1 to 1:10, and more preferably 1:1.05 to 1:8. The organic solvent is preferably C5 to C 10 Alkanes or C6~C 15 The mixed reaction process is as follows: slowly drop an organic solution of an organic phosphine compound into an organic solvent solution of a vanadium compound at 0-20°C, and then react at 20-70°C for 2-40 minutes. After the reaction is completed, remove the organic solvent by reduced pressure distillation at 35-80°C to obtain a main catalyst. Then add co-catalysts in sequence.

[0024] The present invention also discloses an application of the vanadium catalyst system described in the technical solution in the field of ethylene propylene rubber synthesis, which is applied to the synthesis of ethylene propylene diene rubber and ethylene propylene diene rubber.

[0025] The beneficial effects achieved by the present invention are:

[0026] Compared with the prior art, the addition of the organic phosphine compound in the vanadium compound of the present invention can stabilize the vanadium compound and enhance the stability of the vanadium compound. In the copolymerization process of ethylene and propylene, pentavalent vanadium plays a major catalytic role. The presence of the organic phosphine compound changes the electronic properties of the active vanadium, increases the growth rate of the polymerization chain, accelerates the insertion rate of the monomer, improves the reaction activity, and effectively improves the shortcomings of low activity and fast deactivation of traditional vanadium catalysts such as VOCl3 at high temperatures. In addition, since the organic phosphine compound also participates in the composition and polymerization reaction of the active center as an effective component of the catalyst, the formation of gel of EPDM rubber during the polymerization process can be reduced, and the ability of the vanadium compound to regulate the insertion rate of the comonomer is increased, so as to prepare EPDM rubber with controllable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the GPC spectrum of the EPDM rubber prepared in Comparative Example 1 and Example 3;

[0028] Figure 2 The EPDM rubber prepared in Comparative Example 3 and Example 15 1 HNMR spectrum. DETAILED DESCRIPTION

[0029] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0030] Examples 1 to 10

[0031] Taking VOCl3 catalyst as an example, the preparation method of the main catalyst (organic phosphine-modified vanadium compound) is as follows: extract 1 mmol of VOCl3 compound to prepare a 0.1 mol / L VOCl3 hexane solution, add 1 mmol of organic phosphorus compound into cyclohexane solution at 20°C, react the above solution at 45°C for 40 minutes, distill at 50°C under reduced pressure for 6 hours, remove the solvent and set aside.

[0032] Install the reactor used for polymerization, keep it airtight, and replace it with nitrogen 2 to 3 times; add the main catalyst prepared above with a vanadium content of 0.025mmol, 0.75mmol diethylaluminum chloride (Al(C2H5)2Cl), 0.05mmol ethyl trichloroacetate (ETCA), and 50ml hexane in sequence, and introduce a mixed gas with a molar ratio of ethylene and propylene of 1:2, control the polymerization pressure at 0.4MPa, stir, and react at 20℃ for 30min. After the polymerization is completed, add a 5% by mass hydrochloric acid-ethanol solution to the polymerization product, wash it with ethanol, and then dry it under vacuum to obtain EPDM rubber. The glass transition temperature of the obtained polymer was tested by differential calorimetry (DSC); 1 H NMR spectrum analysis, the bound ethylene mass content (C2wt%) of the obtained polymer; the molecular weight and molecular weight distribution of the sample were tested by gel permeation chromatography-high temperature GPC. Specific test data are shown in Table 1.

[0033] Table 1 Effect of organophosphorus-modified vanadium compounds on the copolymerization of ethylene and propylene

[0034]

[0035] Polymerization conditions: EASC: Al / V=30, 20°C, 0.4-0.45MPa, 0.5h, ethylene:propylene=1:2mol / mol;

[0036] *: 1 HNMR

[0037] Comparative Example 1

[0038] Refer to Examples 1 to 10 to prepare EPDM rubber using VOCl3 as a vanadium catalyst. Install the reactor used for polymerization, keep it airtight, and replace it with nitrogen 2 to 3 times; add 0.025mmol VOCl3 catalyst with a vanadium content, 0.75mmol diethylaluminum chloride (Al(C2H5)2Cl), 0.05mmol ethyl trichloroacetate (ETCA), and 50ml hexane in sequence; introduce a mixed gas with a molar ratio of ethylene to propylene of 1:2, control the polymerization pressure at 0.4MPa, stir, and react at 20°C for 30min. After the polymerization is completed, add a 5% by mass hydrochloric acid-ethanol solution to the polymerization product, wash it with ethanol, and then dry it under vacuum to obtain 4.24g of EPDM rubber. The catalytic efficiency of the vanadium catalyst is calculated to be 3.33kgEPR / gV·h. According to differential calorimetry (DSC) analysis, the glass transition temperature of the obtained polymer is -46.5°C; 1H NMR spectral analysis showed that the bound ethylene mass content (C2wt%) of the obtained polymer was 68.62%; the number average molecular weight of the sample tested by gel permeation chromatography-high temperature GPC was 11.2×10 4 , molecular weight distribution 2.45.

[0039] Embodiment 11

[0040] Taking the fatty alcohol vanadium complex VOCl3·3IOOH (IOOH is the abbreviation of isooctyl alcohol compound) catalyst as an example, the preparation method of the main catalyst (organic phosphine-modified vanadium compound) is as follows: extract a hexane solution containing 1 mol of VOCl3·3IOOH, add trioctyl phosphine with an equal molar amount of vanadium at 20°C, react at 30°C for 10 minutes, and after the reaction is completed, remove the solvent by reduced pressure distillation at 35°C to obtain the main catalyst. Referring to Examples 1 to 10, 0.75 mmol of triethylaluminum trichloride (Al2(C2H5)3Cl3), 0.025 mmol of the main catalyst prepared above, without adding an active promoter, and 50 ml of hexane were added to a polymerization kettle; a mixed gas with a molar ratio of ethylene to propylene of 1:2 was introduced, the polymerization pressure was controlled at 0.4 MPa, stirred, and reacted at 40°C for 30 min. After the polymerization was completed, a 5% by mass hydrochloric acid-ethanol solution was added to the polymerization product, and the product was washed with ethanol, and then dried under vacuum to obtain 2.22 g of ethylene-propylene rubber, with a calculated catalytic efficiency of 3.48 kgEPR / gV·h, a glass transition temperature Tg of -51.9°C, a polymerized ethylene mass content (C2 wt%) of 60.62%, and Mn=8.25×10 4 ,Mw / Mn=2.75.

[0041] Comparative Example 2

[0042] Reference Example 11, except that the vanadium catalyst used was VOCl3 and no organic phosphine electron donor was added, the yield of the obtained EPDM rubber was 1.65 g, the calculated catalytic efficiency was 2.59 kgEPR / gV·h, the glass transition temperature Tg was -50.9°C, the bound ethylene mass content of the polymer (C2 wt%) was 69.62%, Mn=9.25×10 4 ,Mw / Mn=2.45.

[0043] Example 12

[0044] With reference to Examples 1 to 10, taking VOCl3 catalyst as an example, the preparation method of the main catalyst (triphenylphosphine modified vanadium compound) is as follows: extract 1mmol of VOCl3 compound to prepare 0.02mol / L VOCl3 heptane solution, add 6mmol of triphenylphosphine organic solution at 10°C, mix at 50°C for 30min, and remove organic solvent by reduced pressure distillation at 60°C to obtain the main catalyst. Install the reaction kettle used for polymerization, keep it airtight, and replace it with nitrogen 2 to 3 times; add the main catalyst prepared by the above method with a vanadium content of 0.025mmol, 1.0mmol of ethylaluminum dichloride, 0.15mmol of ethyl trichloroacetate (ETCA), and 50ml of hexane in sequence; pass a mixed gas with a molar ratio of ethylene to propylene of 1:2, control the polymerization pressure at 0.4MPa, stir, and react at 20°C for 30min. Other experimental operations are the same as those of Examples 1-10, and 4.31g of ethylene-propylene rubber is obtained, and the calculated catalytic efficiency is 6.75EPR / gV·h. The glass transition temperature of the obtained polymer was -52.5°C according to differential scanning calorimetry (DSC). 1 H NMR spectral analysis showed that the bound ethylene mass content (C2 wt%) of the obtained polymer was 63.62%; the number average molecular weight of the sample tested by gel permeation chromatography-high temperature GPC was 9.2×10 4 , molecular weight distribution 2.85.

[0045] Example 13

[0046] With reference to Examples 1 to 10, taking VOCl3 catalyst as an example, the preparation method of the main catalyst (tri-(4-n-octyloxyphenyl)phosphine modified vanadium compound) is as follows: extract 1mmol of VOCl3 compound to prepare 0.02mol / L VOCl3 toluene solution, add 10mmol of tri-(4-n-octyloxyphenyl)phosphine at 5°C, mix at 60°C for 5min, and remove the solvent by reduced pressure distillation at 75°C to obtain tri-(4-n-octyloxyphenyl)phosphine modified vanadium compound. Install the reaction kettle used for polymerization, keep it airtight, and replace it with nitrogen 2 to 3 times; add the main catalyst prepared by the above method with a vanadium content of 0.05mmol, 1.0mmol dichloroisobutylaluminum, 0.5mmol ethyl trichloroacetate (ETCA), and 50ml of hexane in sequence, and other experimental operations are the same as in Examples 1 to 10, and 6.41g of ethylene propylene rubber is obtained, and the calculated catalytic efficiency is 5.02EPR / gV·h. The glass transition temperature of the obtained polymer was -50.2°C according to differential scanning calorimetry (DSC). 1 H NMR spectral analysis showed that the bound ethylene mass content (C2 wt%) of the obtained polymer was 67.92%; the number average molecular weight of the sample tested by gel permeation chromatography-high temperature GPC was 11.2×10 4, molecular weight distribution 2.98.

[0047] Examples 14 to 23

[0048] VO(P 204 )2, fatty alcohol vanadium complex VOCl3·3IOOH, amine vanadium complex VO2Cl·TOA, phosphate vanadium complex VO2Cl·3TBP, V(acac)3, octahydroxyquinoline vanadium complex VO(OH)·(8HQ)2, α-benzoin oxime vanadium complex VO(OH)·(DPhOx)2, VO(OBu)3, VCl4 and VO(OEt)Cl2, to prepare the main catalyst (tri(4-methoxyphenyl)phosphine modified vanadium compound), the preparation method is the same as Examples 1 to 10. The polymerization reaction was carried out under the following polymerization conditions: (1) 0.1L reactor, 0.025mmol of the modified vanadium compound prepared by the above method; (2) ENB: 0.23ml; (3) Al2(C2H5)3Cl3: 0.75mmol; (4) ETCA: 0.3mmol; (5) 50ml of solvent hexane; (6) the molar ratio of ethylene to propylene in the mixed gas was 1:2, the pressure was 0.4MPa, and the reaction was carried out at 20℃ for 15min. After the polymerization was completed, a 5% by mass hydrochloric acid-ethanol solution was added to the polymerization product, and the product was washed with ethanol, and then dried under vacuum to obtain EPDM rubber. The specific results are shown in Table 2.

[0049] Table 2 Characterization results of products obtained using different catalysts in Examples 14 to 23

[0050]

[0051]

[0052] Comparative Examples 3-4

[0053] Reference Examples 14 to 23, except that VOCl3 (1) and VO2Cl·3TBP (2) were used as vanadium catalysts to prepare EPDM rubber. The yield of the prepared EPDM rubber was (1) 2.6 g; (2) 3.0 g. The glass transition temperatures of the obtained polymers were (1) -47.2°C; (2) -49.5°C. 1 HNMR spectral analysis showed that the bound ethylene mass content (1) (C2 wt%) of the obtained polymer was 62.25%, and C=C (wt%) was 6.03%; (2) (C2 wt%) was 63.5%, and C=C (wt%) was 7.12%. The number average molecular weight (1) of the sample tested by gel permeation chromatography-high temperature GPC was 7.2×10 4 , molecular weight distribution 2.58; (2) 7.34×10 4 , molecular weight distribution 2.8.

[0054] Embodiment 24

[0055] Referring to Examples 14 to 23, taking VOCl3 catalyst as an example, the preparation method of the main catalyst (tri-(4-n-hexadecyloxyphenyl)phosphine modified vanadium compound) is as follows: extract 1mmol of VOCl3 compound to prepare 0.1mol / L VOCl3 toluene solution, add 1mmol of tri-(4-n-hexadecyloxyphenyl)phosphine toluene solution at 20°C, mix the above solution at 70°C for 30min, and remove the solvent by reduced pressure distillation at 80°C for standby use. Other experimental conditions are the same as those of Examples 14 to 23. The yield of the prepared EPDM rubber is 5.6g, and the glass transition temperature of the obtained polymer is -49.8°C; 1 HNMR spectral analysis showed that the bound ethylene mass content (C2 wt%) of the obtained polymer was 53.87%, and C=C (wt%) was 7.52%. The number average molecular weight of the sample tested by gel permeation chromatography-high temperature GPC was 6.2×10 4 , molecular weight distribution 2.65.

[0056] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A vanadium catalyst system, comprising a main catalyst and a co-catalyst, characterized in that: The main catalyst is composed of a vanadium compound and an organic phosphine compound; The vanadium compound is at least one of VO(OR)3, VO(OR)2Cl, VO(OR)Cl2, VOCl3 and a vanadium complex; The ligand of the vanadium complex is at least one of fatty alcohols, amines, phosphates, octahydroxyquinoline and oximes; The co-catalyst includes an organoaluminum compound; The organic phosphine compound includes structural formula II, Among them, R is C1~C 20 One of alkyl, phenyl, and substituted phenyl; R1 is C1~C 20 The alkyl group; The preparation method of the vanadium catalyst system comprises the following steps: S1: mixing a vanadium compound and an organic phosphine compound in an organic solvent to obtain a main catalyst; S2: mixing the main catalyst and the co-catalyst to obtain a vanadium catalyst system.

2. A vanadium catalyst system according to claim 1, characterized in that: The organic aluminum compound is at least one of triethylaluminum trichloride, ethylaluminum dichloride, diethylaluminum monochloride and isobutylaluminum dichloride.

3. A vanadium catalyst system according to claim 1, characterized in that: The co-catalyst also includes an activation promoter, and the activation promoter is a halogenated alkane or an ester.

4. A vanadium catalyst system according to claim 1, characterized in that: The ratio of the mole number of vanadium in the vanadium compound to the mole number of the organic phosphine compound is 1:1-10.

5. A vanadium catalyst system according to claim 1, characterized in that: In the structural formula II, R1 is C1~C 16 of alkyl.

6. A vanadium catalyst system according to claim 1, characterized in that: In the step S1, an organic solution of an organic phosphine compound is slowly added dropwise to an organic solvent solution of a vanadium compound at 0 to 20°C, and then reacted at a temperature of 20 to 70°C for 2 to 40 minutes. After the reaction is completed, the organic solvent is removed by reduced pressure distillation at 35 to 80°C to obtain a main catalyst.

7. Use of the vanadium catalyst system according to any one of claims 1 to 6, characterized in that: The applications include use in the synthesis of ethylene propylene rubber.

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