Method and catalyst for selective oligomerization of ethylene

Abstract

The present disclosure provides a method and a catalyst for selective oligomerization of ethylene. The raw material for the catalyst consists of a dehydropyridine annulene-type ligand, a transition metal compound, and an organometallic compound in a molar ratio of 1:0.5-100:0.1-5000. The present disclosure also provides a method for selective oligomerization of ethylene accomplished by using the above-mentioned catalyst. The catalyst for selective oligomerization of ethylene has high catalytic activity, high selectivity for the target products 1-hexene and 1-octene, and low selectivity for 1-butene and 1-C.sub.10.sup.+.

Claims

1. A catalyst for selective oligomerization of ethylene, wherein the raw material for the catalyst consists of: a dehydropyridine annulene ligand, a transition metal compound, and an organometallic compound in a molar ratio of 1:0.5-100:0.1-5000; wherein the dehydropyridine annulene ligand has a structural formula as shown in Formula I: ##STR00004## with R.sup.1, R.sup.2, R.sup.3 each independently selected from an alkyl group or an aryl group, wherein the transition metal compound is a compound of a metal from Group IVB-VIIIB, and wherein the organometallic compound is a compound containing a Group IIIA metal.

2. The catalyst according to claim 1, wherein R.sup.1, R.sup.2, R.sup.3 are independently selected from methyl, ethyl, isopropyl, cyclopentyl, cyclohexyl, phenyl, o-methylphenyl, o-ethylphenyl, o-isopropylphenyl, 2,4-dimethylphenyl, 2,4-diethylphenyl, 2,4-diisopropylphenyl, 2,4-dibutylphenyl, 2,6-diisopropylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-dibutylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, naphthyl, anthryl, and biphenyl.

3. The catalyst according to claim 1, wherein the dehydropyridine annulene ligand consists of a plurality of the compounds of Formula I.

4. The catalyst according to claim 1, wherein the transition metal compound is a compound of at least one or more of chromium, molybdenum, tungsten, titanium, cobalt, tantalum, vanadium, zirconium, iron, nickel, or palladium.

5. The catalyst according to claim 4, wherein the compound of chromium has a general formula of CrR.sup.n.sub.m, wherein R.sup.n is an organic anion or a neutral molecule, R.sup.n contains 1-10 carbon atoms, and n is an integer of 1-6.

6. The catalyst according to claim 5, wherein the compound of chromium includes one or more of chromium acetate, chromium isooctanoate, chromium n-octanoate, chromium acetylacetonate, chromium diisoprene, diphenyl chromium, CrCl.sub.3(THF).sub.3, CrCl.sub.2(THF).sub.2, (phenyl)tricarbonylchromium, or hexacarbonylchromium.

7. The catalyst according to claim 1, wherein the organometallic compound includes one or more of an alkyl aluminum compound, an aluminoxane compound, an organoboron compound, and an organic salt.

8. The catalyst according to claim 7, wherein the alkyl aluminum compound includes an alkyl aluminum compound and an aluminoxane compound; wherein the aluminoxane compound is methyl aluminoxane, ethyl aluminoxane, isobutyl aluminoxane, and modified aluminoxane; wherein the molar ratio of the aluminoxane compound to the alkyl aluminum compound is 100-0.01:1.

9. The catalyst according to claim 7, wherein the alkyl aluminum compound is one or more of alkyl aluminum halide, alkyl aluminum hydride, or alkyl aluminum sesquichloride.

10. The catalyst according to claim 7, wherein the organic salt is methyl lithium or methyl magnesium bromide; the inorganic acid is a tetrafluoroboric acid ether complex; the inorganic salt is tetrafluoroborate or hexafluoroantimonate; the organoboron compound includes one or more of boroxine, sodium borohydride, triethylborane, tris(pentafluorophenyl)boron, or tributylborate.

Description

DETAILED DESCRIPTION

(1) The technical solutions of the present disclosure are described in detail below in order to have a clearer understanding of the technical features, objectives and beneficial effects of the present disclosure, but it is not to be construed as limiting the scope of the disclosure.

Example 1

(2) Firstly, this example provides a dehydropyridine annulene ligand L1 (C.sub.84H.sub.50N.sub.2) which is prepared by the following steps.

(3) ##STR00003##

(4) 0.12 g (0.1 mmol) of tetrakis(triphenylphosphino)palladium, 0.76 g (10.5 mmol) of diethylamine, 1.41 g (10.0 mmol) of 4-methyl-2,6-diacetylenylpyridine and 4.67 g (10.0 mmol) of 1,1-diphenyl-4-(triethyl silyl)-1-butene-3-yn-2-yl trifluoromethanesulfonate were successively added to 100 mL of tetrahydrofuran, stirred under reflux for 12 hours. The mixture is cooled, filtered to obtain a solution of the cross-coupling product in tetrahydrofuran.

(5) Without separation and purification, 20 mL of undehydrated tetrabutylammonium fluoride saturated tetrahydrofuran solution was added to the above solution. After stirring at room temperature for 1 hour, the solvent was removed, and 100 mL of dichloromethane was added to dissolve the mixture, then 0.04 g (0.2 mmol) of copper iodide and 0.023 g (0.2 mmol) of tetramethylethylenediamine were added thereto, and the mixture was stirred under reflux for 24 hours. After finally filtering and concentrating, it was separated by n-hexane column chromatography to obtain 4.80 g (8.8 mmol, yield: 88.3%) of ligand L1.

(6) This example also provides a catalyst for selective oligomerization of ethylene which is prepared by the following step:

(7) Dehydrated methylcyclohexane (20 mL), DMAO (methylaluminoxane with trimethylaluminum removed) (0.57 g, 9.9 mmol), triethylaluminum (0.38 g, 3.3 mmol), ligand L1 (81 mg, 67.8 mol), CrCl.sub.3.(THF).sub.3 (12 mg, 33 mol) were added to a 100 mL reactor equipped with stirrer with sufficient N.sub.2 substitution, and the system was reacted at room temperature for 5 min for preparation.

(8) The above-mentioned catalyst for selective oligomerization of ethylene of the present example is used for catalyzing ethylene oligomerization, and the specific steps are as follows:

(9) The 500 mL autoclave was heated to a vacuum for 2 hours, replaced with nitrogen several rounds and charged with ethylene, cooled to a predetermined temperature, and the dehydrated methylcyclohexane (200 mL) and the above catalyst were added.

(10) The oligomerization reaction was carried out at 45° C. and a pressure of 1 MPa. After 30 min of reaction, it was cooled in an ice bath, and the pressure was released. The reaction was terminated with an acidified ethanol having a mass fraction of 10% to obtain an oligomerized product of 61.1 g, and a catalyst activity being 3.7×10.sup.6 g. oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 2

(11) This Example was processed in a manner similar to Example 1, except that R.sub.1 is —H. The oligomerized product obtained is 44.68 g, and the catalyst activity was 2.9×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 3

(12) This Example was processed in a manner similar to Example 1, except that R.sub.2, R.sub.3 are methyl groups. The oligomerized product obtained is 84.15 g, and the catalyst activity is 5.1×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 4

(13) This Example was processed in a manner similar to Example 1, except that R.sub.2, R.sub.3 are naphthyl groups. The oligomerized product obtained is 36.2 g, and the catalyst activity is 2.2×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 5

(14) This Example was processed in a manner similar to Example 2, except that R.sub.2, R.sub.3 are isopropyl groups. The oligomerized product obtained is 103.95 g, and the catalyst activity is 6.3×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 6

(15) This Example was processed in a manner similar to Example 5, except that R.sub.1 is isopropyl group. The oligomerized product obtained is 115.5 g, and the catalyst activity is 7.0×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 7

(16) This Example was processed in a manner similar to Example 2, except that R.sub.2, R.sub.3 are 2,6-diisopropylphenyl groups. The oligomerized product obtained is 100.65 g, and the catalyst activity is 6.1×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 8

(17) This Example was processed in a manner similar to Example 2, except that the pressure of ethylene is 2 MPa. The oligomerized product obtained is 77.55 g, and the catalyst activity is 4.7×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 9

(18) This Example was processed in a manner similar to Example 2, except that the pressure of ethylene is 4 MPa. The oligomerized product obtained is 120.45 g, and the catalyst activity is 7.3×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 10

(19) This Example was processed in a manner similar to Example 2, except that the reaction temperature is 0° C. The oligomerized product obtained is 19.8 g, and the catalyst activity is 1.2×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 11

(20) This Example was processed in a manner similar to Example 2, except that the reaction temperature is 90° C. The oligomerized product obtained is 72.6 g, and the catalyst activity is 4.4×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

Example 12

(21) This Example was processed in a manner similar to Example 2, except that the amount of CrCl.sub.3.(THF).sub.3 is 3 μmol. The oligomerized product obtained is 21.3 g and the catalyst activity is 14.2×10.sup.6 g oligomer/mol Cr..Math.h. The distribution of oligomerized products is shown in Table 1.

Example 13

(22) This Example was processed in a manner similar to Example 9, except that the cocatalyst is MMAO. The oligomerized product obtained is 59.4 g and the catalyst activity is 3.6×10.sup.6 g oligomer/mol Cr..Math.h. The distribution of oligomerized products is shown in Table 1.

Example 14

(23) This Example was processed in a manner similar to Example 9, except that the cocatalyst is MAO. The oligomerized product obtained is 46.2 g, and the catalyst activity is 2.8×10.sup.6 g oligomer/mol Cr..Math.h. The distribution of oligomerized products is shown in Table 1.

Example 15

(24) This Example was processed in a manner similar to Example 9, except that the chromium compound is CrCl.sub.2(THF).sub.2. The oligomerized product obtained is 18.2 g, and the catalyst activity is 1.1×10.sup.6 g oligomer/mol Cr.Math.h. The distribution of oligomerized products is shown in Table 1.

(25) TABLE-US-00001 TABLE 1 Comparison of carbon number distribution of oligomerization products Carbon number distribution Content of 1-C.sub.6.sup.= Content of 1-C.sub.8.sup.= of products C.sub.4 (wt %) C.sub.6 (wt %) C.sub.8 (wt %) >C.sub.10 (wt %) .sup.a(wt %) .sup.b(wt %) Example 1 5.44 38.25 55.29 1.02 92.31 95.21 Example 2 4.54 34.57 59.54 1.35 90.22 96.51 Example 3 4.01 34.01 59.84 2.14 91.03 94.57 Example 4 6.35 37.35 52.57 3.73 94.21 95.68 Example 5 6.37 37.24 54.32 2.07 89.32 97.51 Example 6 3.03 35.68 59.72 1.57 88.21 96.32 Example 7 8.25 33.24 55.85 2.66 95.14 97.01 Example 8 2.04 33.41 63.57 0.98 85.12 96.34 Example 9 3.24 22.76 72.58 1.42 82.01 95.14 Example 10 2.57 27.62 68.54 1.27 83.25 94.57 Example 11 4.68 69.57 23.70 2.05 97.65 93.67 Example 12 2.54 37.87 56.35 3.24 92.54 96.57 Example 13 3.65 34.57 57.76 4.02 91.47 96.08 Example 14 1.17 36.78 59.66 2.39 97.38 97.51 Example 15 7.35 42.69 48.19 1.77 93.65 95.88

(26) In Table 1, a means the percentage content of 1-C6= in C6, and b means the percentage content of 1-C8= in C8. C6=, C8= represents an olefin having a double bond at its end.

(27) Table 2 shows the experimental conditions and catalyst activities of Example 1 to Example 15, wherein (a) is a dehydropyridine annulene-type ligand, (b) is a transition metal compound, and (c) is an organometallic compound.

(28) TABLE-US-00002 TABLE 2 Chromium Example R.sup.1 R.sup.2 R.sup.3 Cocatalyst compound 1 Methyl Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 2 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 3 Methyl Methyl Methyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 4 Methyl Naphthyl Naphthyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 5 —H Isopropyl Isopropyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 6 Isopropyl Isopropyl Isopropyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 7 —H 2,6-Diisopropyl- 2,6-Diisopropyl- DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 phenyl phenyl 8 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 9 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 10 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 11 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 12 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.3•(THF).sub.3 13 —H Phenyl Phenyl MMAO CrCl.sub.3•(THF).sub.3 14 —H Phenyl Phenyl MAO CrCl.sub.3•(THF).sub.3 15 —H Phenyl Phenyl DMAO/Et.sub.3Al CrCl.sub.2•(THF).sub.2 Catalyst activity (a) (b) (c) 10.sup.6 g Reaction Reaction Catalyst Added Added Added oligomer/ temperature pressure concentration amount amount amount mol Example (° C.) (MPa) (mmol Cr/L) μmol μmol mmol Cr .Math. h 1 45 1 0.16 67.8 33 9.9/3.3 3.7 2 45 1 0.16 67.8 33 9.9/3.3 2.9 3 45 1 0.16 67.8 33 9.9/3.3 5.1 4 45 1 0.16 67.8 33 9.9/3.3 2.2 5 45 1 0.16 67.8 33 9.9/3.3 6.3 6 45 1 0.16 67.8 33 9.9/3.3 7.0 7 45 1 0.16 67.8 33 9.9/3.3 6.1 8 45 2 0.16 67.8 33 9.9/3.3 4.7 9 45 4 0.16 67.8 33 9.9/3.3 7.3 10 0 1 0.16 67.8 33 9.9/3.3 1.2 11 90 1 0.16 67.8 33 9.9/3.3 4.4 12 45 1 0.015 6 3 0.9/0.3 14.2 13 45 4 0.16 67.8 33 9.9/3.3 3.6 14 45 4 0.015 67.8 33 13.2 2.8 15 45 1 0.16 67.8 33 1.1 1.1

(29) The above examples demonstrate that the catalyst for selective oligomerization of ethylene has high activity, high selectivity of the target products 1-hexene and 1-octene, and low yield of 1-butene and 1-C.sub.10.sup.+.