Polymerization catalyst and process

Abstract: A composition of matter is provided comprising a catalytic mixture resulting from contacting at least one of each of the following compounds, an pyridine compound, a clay compound, and an organo-nickel compound. Additionally, a process is provided comprising contacting, under polymerization conditions, at least one alpha-olefin, with a catalytic mixture resulting from contacting at least one of each of the following compounds, an pyridine compound, a clay compound, and an organo-nickel compound.

Description: BACKGROUND OF THE INVENTION This invention relates to the field of alpha-olefin polymerization. Various polymerization processes are known in the art. For example, both chromium and titanium catalyst systems are known to polymerize ethylene. However, even these two popular polymerization systems do not provide solutions to all consumer demands. Consequently, research has been conducted to find new and better polymerization schemes. One of the important polymer properties is the molecular weight of the polymer. For example, the molecular weight of polyethylene can influence the following properties of the resin: tensile strength; tear strength; low temperature toughness; softening temperature; impact strength; environmental stress crack resistance; melt fluidity; and melt drawability. Consequently, methods are constantly sought which would provide a means to control the molecular weight of a polyolefin. SUMMARY OF THE INVENTION It is an object of this invention to provide an improved polymerization process. It is another object of this invention to provide an improved polymerization process which provides an improved molecular weight control. It is still another object of this invention to provide an improved catalyst system. It is still yet another object of this invention to provide an improved catalyst system which provides improved molecular weight control. In accordance with this invention a composition of matter is provided comprising a catalytic mixture resulting from contacting at least one of each of the following compounds, an pyridine compound, a clay compound, and an organo-nickel compound. In another embodiment of this invention a process is provided comprising contacting, under polymerization conditions, at least one alpha-olefin, with a catalytic mixture resulting from contacting at least one of each of the following compounds, an pyridine compound, a clay compound, and an organo-nickel. DETAILED DESCRIPTIONS OF THE INVENTION Pyridine Compounds The pyridine compounds useful in this invention are those compounds which are characterized by the following formula: wherein each R is independently selected from the group consisting of Hydrogen and -COOH, provided that at least one R is a -COOH group. Examples of suitable compounds include, but are not limited to, pyridine-2-carboxylic acid (also known as picolinic acid), pyridine-3-carboxylic acid (also known as nicotinic acid), pyridine-4-carboxylic acid, pyridine-2,4-dicarboxylic acid, pyridine-2,5-dicarboxylic acid and pyridine-2,4,6-tricarboxylic acid. Preferred compounds are the mono-pyridine carboxylic acids and most preferred is pyridine-2-carboxylic acid. The molar ratio of acid compound to nickel should initially be in the range of 0.01 to 2. Preferably the molar ratio of acid compound to nickel is in the range of 0.25 to 1.75 and most preferably it is in the range of 0.5 to 1.5 inclusive. These ranges during the initially contacting of the catalyst reactants are important because of the resulting complex reactions after contacting. Clay Compounds Various clays can help form a polymer of high molecular weight. The initial weight ratio of the clay compound to nickel is generally in the range of 1 to 500. Preferably the weight ratio of clay compound to nickel is in the range of 10 to 300 and most preferably it is in the range of 25 to 200 inclusive. These ranges during the initial contacting of the catalyst reactants are important because of the resulting complex reactions after contacting and because of various economic and polymer considerations. General classes of clay compounds useful in this invention are aluminum silicates, magnesium silicates, or aluminum-magnesium silicates. Examples of suitable clay compounds useful in this invention include, but are not limited to: (1) attapulgite, an aluminum-magnesium silicate. (2) bentonite, an aluminum silicate. (3) halloysite, an aluminum silicate. (4) hectorite, a magnesium silicate. (5) kaolinite, an aluminum silicate. (6) montmorillonite, an aluminum silicate. (7) pyrophylite, an aluminum silicate. (8) sepiolite, a magnesium silicate. (9) talc, a magnesium silicate. (10) vermiculite, an aluminum-magnesium silicate. Particularly preferred clay catalyst supports are the magnesium silicates such as sepiolite. It is preferred that the clay compound be conditioned prior to use. This conditioning comprises subjecting the clay compound to a conditioning temperature in the range of 200° to 800°C, preferably 300° to 700°C, and most preferably 400° to 600°C. The clay compound should be subjected to this conditioning temperature for a period of 5 minutes to 50 hours, preferably 30 minutes to 25 hours, and most preferably 1 hour to 10 hours. The composition of matter according to the present invention is by combining said clay compound with a solvent to form a first mixture; and thereafter combining said first mixture with said pyridine compound and an organo-nickel compound to form a second mixture. Organo-Nickel Compounds The characteristics of these compounds are as follows. The nickel component of the compound should already be in a zero valence state or it should be able to undergo reduction to a zero valence state, before formation of the active nickel component. The organic component should be an unsaturated, compound. An example of a nickel compound useful in this invention is bis(1,5-cyclooctadiene) nickel (referred to hereafter as (COD) 2 Ni). These three components of the catalytic mixture, (pyridine compound, clay compound, and organo-nickel compound), can be contacted in any order and in any manner known in the art. Alpha-olefins The alpha-olefins which can be polymerized by this invention are those alpha-olefins with 2 to 16 carbon atoms in the molecule. Preferably the alpha-olefin molecules have from 2 to 12 carbon atoms and most preferably they have 2 to 8 carbon atoms. Furthermore, these alpha-olefins can either be linear or branched. Examples of alpha-olefins suitable for this invention include, but are not limited to, ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene. It is also within the scope of this invention to copolymerize any of the above monomers with one of the other monomers. Polymerization Conditions The reaction temperature can be in the range of 0°C to 300°C. Preferably the reaction temperature is between 10°C and 200°C and most preferably it is in the range of 20°C to 160°C inclusive. The reaction pressure can be in the range of 170 KPa to 69 MPa (about 10 psig to about 10000 psig). Preferably it is in the range of 445 KPa to 7 MPa (about 50 to about 1000 psig) and most preferably it is in the range of 790 KPa to 4.25 MPa (100 to 600 psig). The reaction time can be in the range of 1 minute to 100 hours. Preferably it is in the range of 5 minutes to 50 hours and most preferably it is in the range of 1 to 10 hours. Examples These examples are provided to further assist a person skilled in the art with understanding this invention. The particular reactants, conditions, and the like, are intended to be generally illustrative of this invention and are not meant to be construed as unduly limiting the reasonable scope of this invention. In each run below, ethylene was contacted with (COD) 2 Ni, picolinic acid, if used, and either bentonite or sepiolite, if used. The reactions were conducted in a 1 liter, stainless steel, stirred reactor. The reactor's contents were substantially free from oxygen which would have adversely affected the polymerization reaction. A solvent and either the bentonite or the sepiolite, if used, were added to the reactor first. These components were then briefly stirred after being purged with ethylene. Subsequent to this stirring the (COD) 2 Ni, and the picolinic acid, if used, were added to the reactor. The chemicals in the reactor were then stirred for 15 minutes. Ethylene was then pressured into the reactor along with a comonomer, if used. The ethylene pressure was then maintained at a nearly constant pressure. The reactions were then terminated by venting the excess ethylene. Any resulting solid material was then separated and recovered. In general, the recovered solid was washed in toluene and/or methanol and then dried and weighed. Thereafter, the characteristics of the solid material were determined. The results are presented in Tables I-A, I-B, I-C, I-D and I-E. The run numbers in each table refer to the same run (i.e. run 1 in Table I-A, is also run 1 in Table I-B). Polymerization Conditions Run Number Solvent Amount of Solvent Reaction Time Ethylene Pressure Range Reactor Temperature Range 1 isobutane 1000 3.61 3.45 → 3.65 (485 → 515) 25.4 → 33.8 2 toluene 350 2.13 3.40 → 3.55 (480 → 500) 22.4 → 106 3 toluene 350 4.97 3.50 → 3.55 (490 → 500) 20.9 → 38.7 4 toluene 350 1.13 2.17 → 3.55 (300 → 500) 22.6 → 157.8 5 toluene 350 2.04 3.50 → 3.52 (490 → 495) 25.1 → 37.3 6 n-heptane 350 7.78 3.45 → 3.52 (485 → 495) 23.0 → 36.1 7 isobutane 1000 2.24 3.40 → 3.60 (480 → 505) 25.5 → 36.5 8 isobutane 800 2.36 3.40 → 3.52 (480 → 495) 27.0 → 42.7 toluene 150 9 toluene 350 2.06 3.40 → 3.50 (480 → 490) 25.8 → 41.2 10 isobutane 1000 3.81 3.40 → 3.60 (480 → 505) 29.4 → 33.6 11 toluene 350 2.40 1.37 → 1.50 (185 → 200) 22.5 → 29.6 12 isobutane 1000 2.44 3.50 → 3.60 (490 → 505) 23.3 → 31.3 13 toluene 350 3.11 3.50 → 3.52 (490 → 495) 22.9 → 34.3 14 toluene 350 1.63 3.50 → 3.55 (490 → 500) 19.0 → 32.5 Catalyst System Components Run Number Component 1 Type/Amount Component 2 Amount/Calculate Amount of Ni Component 3 Amount 1 S/1.63 0.13/0.028 0 2 S/2.66 0.22/0.047 0.0794 3 S/3.14 0.10/0.021 0.0366 4 B/2.86 0.14/0.030 0.0347 5 B/2.38 0.06/0.013 0.0286 6 S/1.97 0.09/0.019 0.0285 7 S/2.45 0.18/0.038 0.0806 8 S/2.32 0.13/0.028 0.0435 9 S/2.39 0.13/0.028 0.0457 10 S/2.16 0.14/0.030 0.0631 11 S/1.90 0.11/0.023 0.0293 12 S/3.24 0.16/0.034 0.0639 13 None 0.41/0.088 0.1795 14 None 0.43/0.092 0.2043 Run Number Component 1/ Calculated Amount of Ni Component 3/ Calculated Amount of Ni 1 58 0 2 57 1.7 3 150 1.7 4 95 1.2 5 180 2.2 6 100 1.5 7 64 2.1 8 83 1.6 9 85 1.6 10 72 2.1 11 82 1.3 12 95 1.9 13 0 2.0 14 0 2.2 Reaction Results Run Number Polymer Yield (g) Time (hours) Productivity g. polymer/g.Ni/hr. 1 0 3.61 NA 2 41.3 2.13 410 3 82.4 4.97 780 4 41.5 1.13 1200 5 55.3 2.04 2100 6 149.5 7.78 1000 7 103.8 2.24 1200 8 156.5 2.36 2400 9 113.5 2.06 2000 10 3.6 3.81 32 11 43.7 2.40 780 12 152.3 2.44 1800 13 37.6 3.11 140 14 15.4 1.63 100 As can be seen from the above, the pyridine compound is very important to the polymerization. This is evidenced by run number one which discloses that without the pyridine compound no polymer was formed. Furthermore, the importance of the clay compound is evidenced by run numbers thirteen and fourteen. In these runs it is evident that without the clay compound very low productivities were obtained. It should be noted that run number ten is considered an abnormal run that is not consistent with this invention. Analysis of Polymer Run Number Melt Index High Load Melt Index HLMI/MI Ratio Remarks 1 NA NA NA R1 2 1.36 137.3 106 3 0.41 43.5 107 4 NA NA NA R4 5 1.44 126.0 88 6 0.11 16.0 198 7 0.01 4.6 139 8 0.07 13.3 195 9 0.86 81.1 94 10 ND ND ND R10 11 1.58 163.6 104 12 ND ND ND 13 4.7 8545 1818 14 32.6 ND ND ND = not determined NA = not applicable The data in Table I-E discloses that very low melt indexes are achieved with the clay compounds. This is evidenced by runs 2, 3, 5-9, and 11 when compared to runs 13 & 14.

Claims: A composition of matter comprising at least one of each a pyridine compound, a clay compound, and an organo-nickel compound, wherein said pyridine compound contains at least one -COOH group, the initial weight ratio of the clay compound to nickel is from 1 to 500, said clay compound is selected from aluminum silicates, magnesium silicates, and aluminum-magnesium silicates, the nickel compound is in the zero valence state or able to undergo reduction to the zero valence state, and the organic compound is an unsaturated compound. The composition of matter of claim 1, wherein said pyridine compound is selected from pyridine-2-carboxylic acid, pyridine-3-carboxylic acid, pyridine-4-carboxylic acid, pyridine-2,4-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, pyridine-2,4,6-tricarboxylic acid, and mixtures thereof. The composition of matter of claim 2, wherein said pyridine compound is selected from pyridine-2-carboxylic acid, pyridine-3-carboxylic acid, and pyridine-4-carboxylic acid. The composition of matter of claim 3, wherein said pyridine compound is pyridine-2-carboxylic acid. The composition of matter of any of the preceding claims, wherein said pyridine compound is initially present in said catalytic mixture in a molar ratio of pyridine compound to nickel of 0.01 to 2. The composition of matter of any of the preceding claims, wherein said clay compound is selected from aluminum silicate clays, magnesium silicate clays, aluminum-magnesium silicate clays, and mixtures thereof. The composition of matter of any of the preceding claims, wherein said clay compound is a magnesium silicate clay. The composition of matter of claim 6 or 7, wherein said clay compound is selected from attapulgite, bentonite, halloysite, hectorite, kaolinite, montmorillonite, pyrophylite, sepiolite, talc, vermiculite, and mixtures thereof. The composition of matter of claim 8, wherein said clay compound is selected from sepiolite, bentonite, and mixtures thereof. The composition of matter of any of the preceding claims, wherein said nickel compound is bis(1,5-cyclooctadiene)nickel. Use of a composition of matter of any of claims 1 to 10 in a process for polymerizing at least one alpha-olefin. The use of claim 11, wherein said polymerization conditions comprise a reaction temperature of 0 to 300 °C, a reaction pressure of 69 kPa gauge to 69 MPa gauge and a reaction time of 1 min to 100 h. The use of claim 11 or 12 wherein said alpha-olefin has 2 to 12 carbon atoms per molecule. The use of claim 13, wherein said alpha-olefin is selected from ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 3-me-thyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, and mixtures thereof. The use of claim 14, wherein said alpha-olefin is ethylene. A process for preparing a composition of matter of any of claims 1 to 10 characterized by: (a) combining said clay compound with a solvent to form a first mixture; and thereafter (b) combining said first mixture with said pyridine compound and said organo-nickel compound to form a second mixture.

Inventors: JACKSON MARGIE FAYE, KNUDSEN RONALD DOUGLAS, SHVEIMA JOSEPH SAMUEL, JACKSON, MARGIE FAYE, KNUDSEN, RONALD DOUGLAS, SHVEIMA, JOSEPH SAMUEL
Applicants: PHILLIPS PETROLEUM CO, PHILLIPS PETROLEUM COMPANY
Application year: 1992
Main classification: C08F4
IPC codes: B01J31, C08F10, C08F4