Organic polymer carrier, main catalyst, ethylene polymerization catalyst composition and application thereofTechnical Field
The invention relates to the field of ethylene polymerization, in particular to the field of ethylene trimerization or ethylene tetramerization, and more particularly relates to an organic polymer carrier, a supported ethylene polymerization main catalyst containing the organic polymer carrier, an ethylene polymerization catalyst composition and application thereof.
Background
Ethylene oligomerization is one of the most important reactions in the olefin polymerization industry, by which inexpensive small molecule ethylene can be converted into products with high added value, i.e., different long chain alpha-olefins. Since the 70 s of the last century, research on the polymerization and oligomerization of olefins catalyzed by transition metal complexes has been increasingly receiving attention from scientists, and efforts have been made to develop new catalysts and to improve existing catalysts, to increase the activity of the catalysts and the selectivity of the catalytic products. Among the many studies that have been carried out the earliest and most rapidly, the more concentrated are nickel-based cationic catalytic systems, as reported earlier in U.S. Pat. nos. 3686351a and 3676523a, and the shell corporation SHOP process based on this patent technology. O-P bridged ligand is involved in shell company SHOP process, but the catalyst contains toxic organic phosphorus group, and has complex synthesis steps and poor stability. A number of patents such as the O-O, P-N, P-P and N-N type complex nickel catalysts have been developed later, such as JP11060627, WO9923096A1, WO991550, CN1401666A, CN1769270A, etc. However, the catalysts obtained from the above patents have the disadvantage of being relatively complex in terms of the preparation process.
Patent WO04056478 by Sasol discloses a PNP framework catalyst with a C8 component selectivity of about 66wt% and a C6 component selectivity of about 21wt% in ethylene tetramerization, wherein the content of 1-hexene in the C6 component is only 82%, and the total selectivity of 1-hexene and 1-octene is about 84%. In US20100137669A1 patent a PCCP symmetric framework catalyst is disclosed which is more stable than the PNP system in ethylene tetramerisation reactions, with a total selectivity of 1-hexene and 1-octene not exceeding 85%. The prior art also attempts to increase the reaction temperature to increase the 1-hexene content in the C6 component, but tends to result in a rapid decrease in the 1-octene content of the most predominant target product.
In these reaction systems, the byproducts such as cycloolefin and cyclized product present in the C6 product can be removed by separation and purification, but the economy of the whole process is disadvantageous. Thus, it is of some challenging importance how to increase the content of 1-hexene in the C6 component while maintaining a higher 1-octene content in the reaction product, thereby increasing the economics of the process. On the other hand, the reaction systems are basically homogeneous catalysis, and the related technologies of the supported ethylene oligomerization catalyst are less, and mainly the selection of the carrier is difficult. In particular, the application of the microporous organic polymer supported ethylene oligomerization catalyst is rarely reported.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides a novel organic polymer carrier for a supported metal catalyst, which can be applied to an ethylene polymerization catalyst for ethylene polymerization reaction, and has the advantages of long catalyst activity duration, low cocatalyst consumption and good catalyst performance.
The first aspect of the present invention provides an organic polymer carrier for a supported metal catalyst, the organic polymer carrier having a structural formula shown in formula (I),
In the formula (I), R1、R2、R3、R4 are the same or different, are each independently selected from at least one of hydrogen, alkyl of C1-C30 and halogen, and at least one is selected from fluorine atoms; r5 is selected from the group consisting of alkyl of C1-C30, cycloalkyl of C3-C30, aryl of C6-C30.
According to some embodiments of the invention, R1、R2、R3、R4 are the same or different and are each independently selected from at least one of hydrogen, alkyl of C1-C20, and halogen.
According to some embodiments of the invention, R5 is selected from the group consisting of C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, preferably R5 is selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclopropyl, cyclopentyl, cyclohexyl, phenyl, or substituted phenyl.
According to some embodiments of the invention, the organic polymer carrier has a high surface area microporous structure.
According to some embodiments of the invention, the organic polymer carrier has a surface area of 300-1500m2·g-1; the pore volume is 0.5-1.8cm3·g-1.
According to some embodiments of the invention, the organic polymer carrier is obtained by polymerization of an organic ligand monomer comprising the general formula (II) by means of solvothermal polymerization,
In the formula (II), R1'、R2'、R3'、R4' are the same or different, and are each independently selected from at least one of hydrogen, alkyl of C1-C30 and halogen, and at least one is selected from fluorine atoms; r5' is selected from the group consisting of alkyl of C1-C30, cycloalkyl of C3-C30, aryl of C6-C30.
According to some embodiments of the invention, preferably, R1'、R2'、R3'、R4' are the same or different, each independently selected from at least one of hydrogen, alkyl of C1-C20, and halogen.
According to some embodiments of the invention, preferably, R5' is selected from the group consisting of alkyl of C1-C20, cycloalkyl of C3-C20, aryl of C6-C20; more preferably, R5 is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, cyclopropyl, cyclopentyl, cyclohexyl, phenyl or substituted phenyl.
According to some embodiments of the invention, preferably, the organic ligand monomer is selected from the following compounds:
in the formula (II), R1＝R2＝R3＝H,R4＝2-F,R5＝i Pr;
in the formula (II), R1＝R3＝H,R2＝R4＝2-F,R5＝i Pr;
in the formula (II), R1＝H,R2＝R3＝R4＝2-F,R5＝i Pr;
in formula (II), R1＝R2＝R3＝H,R4＝2-F,R5＝t Bu;
in formula (II), R1＝R2＝R3＝H,R4＝2-F,R5＝Cy;
in formula (II), R1＝R2＝R3＝H,R4＝2-F,R5 = Ph.
According to some embodiments of the invention, the polymerization conditions include: the temperature is 0-200deg.C, and the time is 0.1-24h.
According to one embodiment of the present invention, the microporous organic polymer may be obtained by polymerizing a monomer represented by formula (II) under the action of an initiator such as Azobisisobutyronitrile (AIBN).
The second aspect of the invention provides a supported ethylene polymerization main catalyst, comprising the carrier and a metal compound supported on the carrier.
According to some embodiments of the invention, the metal compound is selected from a transition metal compound comprising chromium, molybdenum or tungsten, preferably at least one selected from chromium acetylacetonate, chromium tetrahydrofuran chloride and chromium isooctanoate.
According to some embodiments of the invention, the weight ratio of metal compound to support is from 1:1 to 3000, preferably from 1:10 to 2000, more preferably from 1:100 to 1000.
In a third aspect, the present invention provides an ethylene polymerization catalyst composition comprising the supported ethylene polymerization procatalyst described above and an organoaluminum cocatalyst.
According to some embodiments of the invention, the organoaluminum co-catalyst is selected from at least one of an alkylaluminum compound, an alkylaluminum compound and an alkylaluminum chloride compound, more preferably from at least one of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane and modified methylaluminoxane. In the present invention, the modified methylaluminoxane may be an alkyl modified methylaluminoxane, such as alkyl modified methylaluminoxane MMAO which is conventional in the art.
According to some embodiments of the invention, the molar ratio of procatalyst to organoaluminum cocatalyst, calculated as metal, is in the range of 1:1-2000, preferably in the range of 1:10-1000, more preferably in the range of 1:100-600.
In a fourth aspect, the invention provides a process for the polymerization of ethylene comprising: the ethylene polymerization is carried out in an organic solvent in the presence of said organic polymer support, or said procatalyst, or said ethylene polymerization catalyst composition.
According to some embodiments of the invention, the concentration of the catalyst composition is 0.1 to 10. Mu. Mol/L on a metal basis, calculated on the volume of the organic solvent.
According to some embodiments of the invention, the reaction conditions may be those commonly used in the art. Preferably, the reaction temperature of the ethylene polymerization reaction is 0 to 75 ℃, preferably the reaction temperature is 30 to 75 ℃, more preferably 40 to 75 ℃.
According to some embodiments of the invention, the reaction conditions may be those commonly used in the art. Preferably, the ethylene polymerization reaction has an ethylene pressure of 0.1 to 20.0MPa, preferably 0.5 to 5.0MPa, more preferably 2.0 to 5.0MPa.
Preferably, the ethylene polymerization is ethylene oligomerization, ethylene trimerization or ethylene tetramerization.
According to some embodiments of the invention, the organic solvent comprises aliphatic hydrocarbon compounds and/or aromatic hydrocarbon compounds.
According to some embodiments of the invention, the aliphatic hydrocarbon compound is selected from at least one of linear alkanes, branched alkanes, and cycloalkanes; more preferably at least one of pentane, heptane, hexane, cyclohexane and methylcyclohexane.
According to some embodiments of the invention, the aromatic compound is selected from at least one of benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, monochlorotoluene and derivatives thereof.
According to some embodiments of the present invention, in the above reaction, the supported procatalyst and the cocatalyst may be premixed and then added together into the reaction system, or both components of the supported procatalyst and the cocatalyst may be added separately into the reaction system.
The invention has the beneficial effects that:
(1) According to the organic polymer supported ethylene polymerization main catalyst and the catalyst composition, the metal complex is supported on the organic polymer carrier, so that the carrier can be used as a ligand of an active metal component on one hand and can be used as a carrier with high dispersion and high specific surface area for supporting the active metal component on the other hand, the problems of reduced reactivity, loss of the active component and the like caused by homogeneous catalysis immobilization are solved, the stability of the catalyst is improved, the economical efficiency of industrial application is better, and the cost is lower. The catalyst composition provided by the invention has the catalytic activity exceeding 1X 108g·mol(Cr)-1·h-1 and up to 8X 108g·mol(Cr)-1·h-1, the total selectivity of 1-hexene and 1-octene is more than 92% by weight and up to 96% by weight under different conditions, the byproducts such as cycloolefin and cyclized products are obviously reduced, the polymerization reaction can last for more than 2 hours, and the using amount of the cocatalyst is obviously reduced. Therefore, the catalyst composition provided by the invention has the characteristics of high catalytic activity, high selectivity, high stability and the like, and has good industrial application prospect and economic value.
(2) The organic polymer carrier for the supported metal catalyst can be applied to an ethylene polymerization catalyst for ethylene polymerization reaction, and the ethylene polymerization catalyst has better catalyst performance.
(3) The microporous organic polymer supported ethylene polymerization main catalyst has better stability, novel structure, simple preparation and lower cost. The catalyst has long activity duration and low cocatalyst consumption.
(4) The catalyst composition can effectively catalyze ethylene polymerization, especially ethylene oligomerization, ethylene trimerization and tetramerization, and has high catalyst activity and good product selectivity; and the byproducts such as cycloolefin, cyclized product and the like in the C6 product are obviously reduced.
(5) The catalyst composition provided by the invention has the characteristics of high catalytic activity, high selectivity and the like, and has good industrial application prospect and economic value.
Detailed Description
In order that the invention may be more readily understood, the invention will be described in detail below with reference to the following examples, which are given by way of illustration only and are not limiting of the scope of application of the invention.
The test method and the equipment used in the test are as follows:
(1) In the embodiment of the invention, nuclear magnetic resonance is detected by using a Bruker AV400 type nuclear magnetic resonance apparatus, wherein the detection conditions of nuclear magnetic resonance are as follows: deuterated chloroform is used as solvent.
(2) The room temperature test gas chromatograph adopts an Agilent 7890 chromatograph to detect, wherein the detection conditions of the gas chromatograph are as follows: a chromatographic column SE-54, a high-purity nitrogen carrier gas and a FID detector; the column temperature adopts two-stage temperature programming.
In the present inventiont Bu is tert-butyl,i Pr is isopropyl, cy is cyclohexyl, ph is phenyl, ar is substituted aryl, acac is acetylacetone, 2-EHA is isooctanoic acid, and THF is tetrahydrofuran.
[ PREPARATION EXAMPLE 1]
Preparation of microporous organic Polymer I:
The preparation method of the microporous organic polymer I comprises the following steps: 10mmol of monomer II is added into a hydrothermal synthesis reaction kettle under the protection of nitrogen, 100mL of dry tetrahydrofuran is added, 0.2mmol of AIBN is added, and the temperature is raised to 100 ℃ for reaction for 24 hours. And cooling the reaction liquid to room temperature, carrying out suction filtration, washing a filter cake with tetrahydrofuran for three times, and then carrying out vacuum drying to obtain the microporous organic polymer II. Wherein:
An organic polymer support I-1 (R1＝R2＝R3＝H,R4＝2-F,R5＝i Pr) having a surface area of 920m2·g-1; the pore volume was 1.10cm3·g-1.
An organic polymer carrier I-2 (R1＝R3＝H,R2＝R4＝2-F,R5＝i Pr) with a surface area of 898m2·g-1; the pore volume was 1.05cm3·g-1.
An organic polymer support I-3 (R1＝H,R2＝R3＝R4＝2-F,R5＝i Pr) having a surface area of 867m2·g-1; the pore volume was 1.02cm3·g-1.
Organic polymer support I-4 (R1＝R2＝R3＝H,R4＝2-F,R5＝t Bu) with a surface area of 1005m2·g-1; the pore volume was 1.27cm3·g-1.
An organic polymer support I-5 (R1＝R2＝R3＝H,R4＝2-F,R5＝Cy) having a surface area of 850m2·g-1; the pore volume was 0.82cm3·g-1.
An organic polymer support I-6 (R1＝R2＝R3＝H,R4＝2-F,R5 =ph) having a surface area of 779m2·g-1; the pore volume was 0.80cm3·g-1.
[ PREPARATION EXAMPLE 1]
Preparation of Supported main catalyst PL 1-1:
the preparation method of the supported main catalyst PL1 comprises the following steps: 50g of I-1 were added to the reaction flask under nitrogen, 200mL of cyclohexane was added, 0.05g of chromium acetylacetonate was added with stirring, and the temperature was raised from room temperature to 60℃and stirring was continued overnight. Stopping the reaction, and removing the solvent from the reaction solution by using a rotary evaporator to obtain solid powder, namely the supported main catalyst PL1-1.
[ PREPARATION EXAMPLE 2]
Preparation of Supported main catalyst PL2-1
The procedure is as in preparation 1, except that I-1 is replaced by I-2.
[ PREPARATION EXAMPLE 3]
Preparation of Supported Main catalyst PL3-1
The procedure is as in preparation 1, except that I-1 is replaced by I-3.
[ PREPARATION EXAMPLE 4]
Preparation of Supported main catalyst PL4-1
The procedure is as in preparation 1, except that I-1 is replaced by I-4.
[ PREPARATION EXAMPLE 5]
Preparation of Supported main catalyst PL5-1
The procedure is as in preparation 1, except that I-1 is replaced by I-5.
[ PREPARATION EXAMPLE 6]
Preparation of Supported main catalyst PL6-1
The procedure is as in preparation 1, except that I-1 is replaced by I-6.
[ PREPARATION EXAMPLE 7]
Preparation of Supported Main catalyst PL1-2
The same as in preparation example 1 was repeated except that chromium acetylacetonate was replaced with chromium chloride tetrahydrofuran.
[ Example 1]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
A300 mL stainless steel polymerizer was used. The autoclave was heated to 100 ℃, evacuated, replaced several times with nitrogen, then replaced by ethylene and cooled to the set temperature. Then methylcyclohexane was added at 70℃with 0.1. Mu. Mol of procatalyst PL1-1 (calculated as chromium metal) and cocatalyst-Modified Methylaluminoxane (MMAO) added, the total volume of the mixture being 100mL, wherein the molar ratio of procatalyst PL1-1 to cocatalyst was 1:500, controlling the reaction pressure to 3MPa, introducing ethylene, and carrying out ethylene oligomerization.
After the reaction was continued for 2 hours, the reaction was completed, the system was cooled to room temperature, the gas phase product was collected in a gas metering tank, the liquid phase product was collected in a conical flask, and 1mL of ethanol was added as a terminator to terminate the reaction. The gas-liquid phase product was measured and analyzed by gas chromatography (chromatograph is Hewlett-packard 5890). The data results are shown in Table 1.
[ Example 2]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 2-1.
The difference from example 1 is that the main catalyst PL1-1 was replaced with a main catalyst PL2-1. The data results are shown in Table 1.
[ Example 3]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 3-1.
The difference from example 1 is that the main catalyst PL1-1 was replaced with a main catalyst PL3-1. The data results are shown in Table 1.
[ Example 4]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 4-1.
The difference from example 1 is that the main catalyst PL1-1 was replaced with a main catalyst PL4-1. The data results are shown in Table 1.
[ Example 5]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-2.
The difference from example 1 is that the main catalyst PL1-1 is replaced with a main catalyst PL1-2. The data results are shown in Table 1.
[ Example 6]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure is as in example 1, except that the modified methylaluminoxane is replaced by triethylaluminum. The data results are shown in Table 1.
[ Example 7]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The same as in example 1 was found to be different in that the reaction pressure was replaced with 5MPa from 3 MPa. The data results are shown in Table 1.
[ Example 8]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The difference from example 1 was that the molar ratio of the main catalyst PL1-1 to the cocatalyst was 1:100. the data results are shown in Table 1.
[ Example 9]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure of example 1 was repeated except that the reaction temperature was changed from 70℃to 30 ℃. The data results are shown in Table 1.
[ Example 10]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure is as in example 1, except that the reaction temperature is replaced by 40℃from 70 ℃. The data results are shown in Table 1.
[ Example 11]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure of example 1 was repeated except that the reaction temperature was changed from 70℃to 75 ℃. The data results are shown in Table 1.
[ Example 12]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure is as in example 1, except that the reaction temperature is replaced by 80℃from 70 ℃. The data results are shown in Table 1.
[ Example 13]
The ethylene oligomerization reaction is carried out by adopting a supported main catalyst PL 1-1.
The procedure is as in example 1, except that the reaction temperature is replaced by 100℃from 70 ℃. The data results are shown in Table 1.
Comparative example 1
The ligand Ph2PN(iPr)PPh2 and chromium acetylacetonate are adopted to carry out ethylene oligomerization.
A300 mL stainless steel polymerizer was used. The autoclave was heated to 80 ℃, evacuated, replaced several times with nitrogen, then replaced by ethylene and cooled to the set temperature. Then, methylcyclohexane was added at 70℃and 0.1. Mu. Mol of chromium acetylacetonate, 0.2. Mu. Mol of ligand Ph2PN(iPr)PPh2 and 200mmol of cocatalyst-Modified Methylaluminoxane (MMAO) were added, the total volume of the mixture was 100mL, the reaction pressure was controlled at 3MPa, and ethylene was introduced to carry out ethylene oligomerization.
After 30 minutes, the reaction was stopped, the system was cooled to room temperature, the gas phase product was collected in a gas metering tank, the liquid phase product was collected in a conical flask, and 1mL of ethanol was added as a terminator to terminate the reaction. The gas-liquid phase product was measured and analyzed by gas chromatography (chromatograph is Hewlett-packard 5890). The data results are shown in Table 1.
Comparative example 2
Ethylene oligomerization was carried out using the compound bis [ (S, S) - (o-fluoro-phenyl)2 PCH (Me) CH (Me) P (o-fluoro-phenyl)2 dichloro (μ -chloro) chromium ].
The procedure was as described in example 4 of CN104169003 a. The data results are shown in Table 1.
TABLE 1
As can be seen from the data in Table 1, the organic polymer supported catalyst composition provided by the present invention has a catalytic activity of more than 1X 108g·mol(Cr)-1·h-1, up to 8X 108g·mol(Cr)-1·h-1, and a total selectivity of 1-hexene and 1-octene of 92 wt% or more, up to 96 wt% or more under different conditions. In contrast to example 13, the catalyst composition provided by the present invention is preferably carried out at moderate reaction temperatures, with significantly better catalyst activity and selectivity for 1-octene, yet still having some catalytic activity at high temperatures. Compared with the homogeneous catalyst of comparative examples 1-2, the microporous organic polymer supported catalyst composition provided by the invention has the advantages that the catalyst activity is improved by several times or even more than 10 times, the high 1-octene selectivity is maintained, the content of 1-hexene in C6 is greatly improved, and byproducts such as cycloolefins, cyclized products and the like are obviously reduced. The catalyst loaded by the microporous organic polymer has improved stability, the catalytic activity can be kept for more than 2 hours, the used cocatalyst dosage is obviously reduced, and the catalyst can react even under the condition of low cocatalyst dosage. The catalyst composition disclosed by the invention has better performance, and the microporous organic polymer can improve the dispersity of the metal complex, improve the specific surface area of metal and improve the activity and stability of the catalyst composition.
The selectivity of the 1-octene in the invention is obviously improved. Because of the polyolefin field, in particular POE, C8-LLDPE, PAO new materials and the like, there is a need for a copolymerization grade of high purity 1-octene, which is not in demand in the market, is completely imported in China, and has a price obviously higher than other long chain alpha-olefins; therefore, the process technology with higher 1-octene selectivity has obvious economic benefit and social value.
The supported ethylene polymerization catalyst composition can effectively catalyze ethylene oligomerization, especially ethylene oligomerization, ethylene trimerization and tetramerization, and has the advantages of high catalyst activity, rapid reaction initiation, stable operation, good repeatability, strong practicability and wide industrialization prospect.
What has been described above is merely a preferred example of the present invention. It should be noted that other equivalent modifications and improvements will occur to those skilled in the art, and are intended to be within the scope of the present invention, as a matter of common general knowledge in the art, in light of the technical teaching provided by the present invention.