Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Reexamination Certificate
2001-03-22
2003-04-15
Griffin, Walter D. (Department: 1764)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
C585S521000, C585S523000, C585S524000
Reexamination Certificate
active
06548723
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a multistep preparation of an oligomer oil, and relates more particularly to an aforesaid multistep preparation in which the first step involves the polymerization of a feedstock containing one or more C
3
to C
20
1-olefins in the presence of a metallocene catalyst system comprising a bulky ligand transition metal catalyst and in which a subsequent step involves the oligomerization of at least a preselected fraction of the product of the first step.
2. Discussion of the Prior Art
Numerous processes have been disclosed for polymerizing or oligomerizing an ethylenically unsaturated olefin. For example, Rossi et al., PCT/US93/12102, published on Jun. 23, 1994 as WO 94/13715, discloses a catalyst system comprising a bulky ligand transition metal compound having a formula which is similar to Formula 1, 2, 3 or 4 herein below. The catalyst system also includes an activator compound containing a metal of Group II or III of the Periodic Table of the Elements, especially trialkyl aluminum compounds, alumoxanes both linear and cyclic, or ionizing ionic activators or compounds such as tri(n-butyl) ammonium tetra(pentafluorophenyl) boron. The disclosed process involves copolymerization of ethylene and an alpha-olefin. Suitable alpha-olefins have one hydrogen atom on the second carbon, at least two hydrogens on the third carbon or at least one hydrogen on the fourth carbon. The resulting copolymers produced contain a high degree of terminal ethenylidene or vinylidene unsaturation, and have a number average molecular weight of 300 to 15,000 and a molecular weight distribution (M
w
/M
n
) of typically less than 5.
Bagheri et al., U.S. Pat. No. 5,688,887 discloses another such process for polymerizing a feedstock containing one or more C
3
to C
20
1-olefins and a second hydrocarbon which is not a 1-olefin, to form a highly reactive, low molecular weight, viscous, essentially 1-olefin-containing poly(1-olefin) or copoly(1-olefin) in the presence of a metallocene catalyst comprising a cyclopentadienyl or indenyl Periodic Group IVb metallocene catalyst and aluminoxane cocatalyst. The resulting polymer product has a terminal vinylidene content of more than 80%, is highly reactive and has a molecular weight between 300 and 10,000. Bagheri et al. also discloses reactions of the poly(1-olefin) or copoly(1-olefin) product in which the terminal vinylidene linkage is reacted with an aromatic, an epoxidation agent, a silylation agent, maleic anhydride, carbon monoxide and hydrogen, halogen and hydrohalogen.
A major problem associated with making oligomer oils from vinyl olefins is that the oligomer product mix usually must be fractionated into different portions to obtain oils of a given desired viscosity (e.g., 2, 4, 6 or 8 cSt at 100° C.). As a result, in commercial production it is difficult to obtain an oligomer product mix which, when fractionated, will produce the relative amounts of each viscosity product which correspond to market demand, and it is often necessary to produce an excess of one product in order to obtain the needed amount of the other. Another problem is the lack of control over the chemistry, and isomerization of alpha olefins to internal olefins. A third problem is that polymerization processes often yield a high percentage of dimer, which is unsuitable (too volatile) for use as a lubricant. Therefore, it is highly desirable to develop a process that provides the versatility of allowing the viscosity of the product to be tailored with improved selectivity and product oils having a pre-selected desired viscosity to be manufactured reproducibly and easily.
Schaerf et al., U.S. Pat. Nos. 5,284,988 and 5,498,815 disclose two two-step processes for preparing a synthetic oil that do provide improved versatility of allowing one to tailor the viscosity of the synthetic oil product with improved selectivity. U.S. Pat. No. 5,284,988 discloses a process which provides improved selectivity when forming synthetic oils using as starting olefins, vinylidene olefins and alpha-olefins. The process of U.S. Pat. No. 5,284,988 for making a synthetic oil comprises (a) isomerizing at least a portion of a vinylidene olefin feed in the presence of an isomerization catalyst to form an intermediate which contains tri-substituted olefin and (b) codimerizing the intermediate and at least one vinyl olefin in the presence of an oligomerization catalyst to form a synthetic oil which comprises a co-dimer of the vinylidene olefin and the vinyl olefin. Suitable vinylidene olefins for use in the isomerization step of the process of U.S. Pat. No. 5,284,988 can be prepared using known methods such as by dimerizing vinyl olefins containing from 4 to about 30 carbon atoms, preferably at least 6, and most preferably at least 8 to about 20 carbon atoms, including mixtures thereof. Suitable vinyl olefins for use in the codimerization step of the process of U.S. Pat. No. 5,284,988 contain from 4 to about 30 carbon atoms, and, preferably about 6 to about 24 carbon atoms, including mixtures thereof. The codimerization step can use any suitable dimerization catalyst known in the art and especially Friedel-Crafts type catalysts such as acid halides (Lewis Acid) or proton acid (Bronsted Acid) catalysts, which can be used in combination and with promoters.
U.S. Pat. No. 5,498,815 discloses a process for making a synthetic oil which comprises the steps of reacting a vinylidene olefin in the presence of a catalyst to form an intermediate mixture which contains at least about 50 weight percent dimer of the vinylidene olefin, and thereafter adding a vinyl olefin to the intermediate mixture and reacting the intermediate mixture and the vinyl olefin in the presence of a catalyst so as to form a product mixture which contains the dimer of the vinylidene olefin and a co-dimer of the added vinyl olefin with the vinylidene olefin. Suitable vinylidene olefins for use in the first step of this process can be prepared using known methods, such as by dimerizing vinyl olefins containing from 4 to about 30 carbon atoms. Suitable vinyl olefins for use in the second step of this process contain from 4 to about 30 carbon atoms. Both steps can use any suitable dimerization catalyst known in the art and especially Friedel-Crafts type catalysts such as acid halides (Lewis Acid) or proton acid (Bronsted Acid) catalysts, which catalysts can be used in combination and with promoters.
Hobbs et al., PCT/US90/00863, published on Sep. 7, 1990 as WO 90/10050, discloses a method for improving the thermal stability of synthetic lubricants composed of alpha-olefin oligomers by alkylation thereof in the presence of an acid alkylation catalyst with an olefin such as decene or the lower molecular weight, non-lubricant range olefins produced in the course of the oligomerization of 1-alkenes. The alpha-olefin oligomers are obtained by oligomerization of C
6
to C
20
alpha-olefin feedstock in the presence of a reduced valence state Group VIB metal catalyst on a porous support and recovering from the resulting product mixture oligomers comprising olefinic lubricant range hydrocarbons.
However, neither U.S. Pat. No. 5,284,988, nor U.S. Pat. No. 5,498,815 nor PCT/US90/00863 discloses a multistep process that involves in the first step the polymerization of an olefin in the presence of a metallocene catalyst system comprising a bulky ligand transition metal complex to form a product mixture comprising a distribution of products at least a fraction of which have properties that are outside of a predetermined range therefor, and in a subsequent step the oligomerization of at least a pre-selected fraction of the product mixture formed in the first step.
OBJECTS OF THE INVENTION
It is therefore a general object of the present invention to provide an improved process for producing an oligomer oil having predetermined properties which overcomes the aforesaid problems of prior out methods.
More particularly, it is an object of the present invention to provide an improved afor
Bagheri Vahid
Benda Ranier
Eisenberg David C.
Lanier Carroll W.
Ratliff Kevin S.
BP Corporation North America Inc.
Griffin Walter D.
Henes James R.
Nguyen Tam M.
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