Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-11-05
2004-02-03
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S171000, C502S172000, C502S226000, C568S851000
Reexamination Certificate
active
06686307
ABSTRACT:
The present invention relates to magnesium dichloride/alcohol adducts which are characterized by particular chemical and physical properties. The adducts of the present invention are particularly useful as precursors of catalyst components for the polymerization of olefins.
MgCl
2
.alcohol adducts and their use in the preparation of catalyst components for the polymerization of olefins are well known in the art.
J. C. J. Bart and W. Roovers [Journal of Material Science, 30 (1995), 2809-2820] describe the preparation of a number of MgCl
2
.nEtOH adducts, with n ranging from 1.4 to 6, and their characterization by means of X-ray powder diffraction. A range of allegedly new adducts, with n=6, 4.5, 4, 3.33, 2.5, 1.67, 1.50 and 1.25, is characterized in terms of X-ray diffraction pattern. According to the authors, the MgCl
2
.alcohol adducts can be converted to active polymerization catalyst supports through the elimination of the alcohol molecules from the adducts by thermal desolvation. In table III of the article, the characteristic diffraction lines of the above indicated new adducts are reported with reference to the interplanar distances. For convenience, the same diffraction lines are reported below with reference to the 2&thgr; diffraction angles, limited to the range of 2&thgr; diffraction angles between 5° and 15° (the relative intensity I/I
o
with respect to the most intense diffraction line is reported in parentheses). For n=1.25: 2&thgr;=7.6° (100), 12.28° (25), 14.9° (8); for n=1.5: 2&thgr;=8.44 (100), 11.95 (48), 14.2 (46); for n=1.67: 2&thgr;=6.1° (9), 6.68° (100), 8.95° (50), 9.88° (33), 11.8° (8), 12.28° (33), 14.5° (13), 14.75° (4); for n=2.5: 2&thgr;=6.3 (27), 9.4° (100), 9.93° (70), 11.7° (11), 12.35° (6), 14.90 (6); for n=3.33: 2&thgr;=9.14° (15), 9.44° (100), 11.88° (15), 12.9° (27); for n=4: 2&thgr;=8.7° (49), 10.1° (73), 10.49° (100), 11.8° (58); for n=4.5: 2&thgr;=9.65° (100), 11.4° (10), 12.5° (24), 12.94° (32), 14.25° (20), 14.95° (6); for n=6: 2&thgr;=8.94° (100), 13.13° (3). A MgCl
2
.2EtOH.0.5H
2
O adduct is also reported, the diffraction lines of which in the relevant range are the following: 2&thgr;=7.9° (35); 8.5° (>100); 9.7° (26); 11.32° (100); 12.59° (11); 13.46° (12).
Catalyst components for the polymerization of olefins, obtained by reacting MgCl
2
.nEtOH adducts with halogenated transition metal compounds, are described in U.S. Pat. No. 4,399,054. The adducts are prepared by emulsifying the molten adduct in an immiscible dispersing medium and quenching the emulsion in a cooling fluid to collect the adduct in the form of spherical particles. No X-ray characteristics of the adducts are reported.
U.S. Pat. No. 4,421,674 describes a method for preparing a catalyst component for the polymerization of olefins which involves the preparation of MgCl
2
.EtOH adducts by means of the following steps: (a) preparation of a MgCl
2
solution in ethanol; (b) spray-drying said solution to collect particles of the adduct in spherical form, said adduct having from 1.5 to 20% by weight of residual alcoholic hydroxyl content and being characterized by an X-ray spectrum in which the maximum peak at 2.56 Å (i.e. 2&thgr;=35°) characteristic of the crystalline anhydrous MgCl
2
is practically absent and a new maximum peak at about 10.8 Å (i.e. 2&thgr;=8.15°) is present; lesser peaks at about 9.16 Å (i.e. 2&thgr;=9.65°) and 6.73 Å (i.e. 2&thgr;=13.15°) are also reported.
EP-A-700936 describes a process for producing a solid catalyst component for the polymerization of olefins which comprises the preparation of MgCl
2
.EtOH adducts by means of the following steps: (A) preparation of a mixture having formula MgCl
2
.mROH, wherein R is an alkyl group with 1 to 10 carbon atoms and m=3.0 to 6.0; (B) spray-cooling said mixture to obtain a solid adduct having the same composition as of the starting mixture; (C) partly removing the alcohol from the above-obtained solid adduct to obtain an adduct containing from 0.4 to 2.8 mol of alcohol per mol of MgCl
2
. The adduct obtained in (C) is characterized by an X-ray diffraction spectrum in which a novel peak does not occur at diffraction angles 2&thgr;=7 to 8° as compared with the diffraction spectrum of the adduct obtained in (B), or even if it occurs, the intensity of the novel peak is 2.0 times or less the intensity of the highest peak present at the diffraction angles 2&thgr;=8.5 to 9° of the diffraction spectrum of the adduct obtained in (C). FIG. 2 of said European Patent Application shows a typical X-ray diffraction spectrum of the adducts prepared in (B). The highest peak occurs at 2&thgr;=8.8°; two less intense peaks occur at 2&thgr;=9.5 to 10° and 2&thgr;=13°, respectively. FIG. 3 shows a typical X-ray diffraction spectrum of the adducts prepared in (C). The highest peak occurs at 2&thgr;=8.8°; other peaks occur at 2&thgr;=6.0 to 6.5°, 2&thgr;=9.5 to 10° and 2&thgr;=11 to 11.5°. FIG. 4 shows a typical X-ray diffraction spectrum of comparative adducts prepared in (C) The highest peak occurs at 2&thgr;=7.6°; other peaks occur at 2&thgr;=8.8°, 2&thgr;=9.5 to 10°, 2&thgr;=11 to 11.5° and 2&thgr;=12 to 12.5°.
A new MgCl
2
.alcohol adduct has now been found which is characterized by a particular X-ray diffraction spectrum, not shown by the adducts of the prior art, and/or by a particular crystallinity as shown by the Differential Scanning Calorimetry (DSC) profile of the adduct. In addition, particular MgCl
2
.alcohol adducts of the present invention can be characterized by their viscosity values in the molten state which, for a given alcohol content, are higher than the viscosity values of the corresponding adducts of the prior art. In addition to the alcohol, minor amounts of water can also be present in the adducts according to the invention.
The adducts of the present invention can be used to prepare catalyst components for the polymerization of olefins by reaction with transition metal compounds. Catalyst components obtained from the adducts of the present invention are capable of giving catalysts for the polymerization of olefins characterized by enhanced activity and stereospecificity with respect to the catalysts prepared from the adducts of the prior art. Also, the morphological properties of the obtained polymers are improved, particularly when adducts in spherical forms are used.
The present invention therefore relates to MgCl
2
.mROH.nH
2
O adducts, where R is a C
1
-C
10
alkyl, 2≦m≦4.2, 0≦n≦0.7, characterized by an X-ray diffraction spectrum in which, in the range of 2&thgr; diffraction angles between 5° and 15°, the three main diffraction lines are present at diffraction angles 2&thgr; of 8.8±0.20, 9.4±0.20 and 9.8±0.20, the most intense diffraction line being the one at 2&thgr;=8.8±0.2°, the intensity of the other two diffraction lines being at least 0.2 times the intensity of the most intense diffraction line.
The above described diffraction pattern is unique and it has never been described in the prior art. In fact, none of the spectra reported in Bart et al. corresponds to the spectrum which characterizes the adducts of the present invention; the same applies to the adducts disclosed in EP-A-700936. As for the adducts described in U.S. Pat. No. 4,399,054, applicants repeated the preparation of the adducts according to the procedure described therein. The X-ray diffraction spectrum of the obtained adduct shows, in the range of 2&thgr; diffraction angles between 5 and 15°, the following main peaks (the relative intensity I/I
o
with respect to the most intense diffraction line is in parentheses): 2&thgr;=8.84° (79); 2&thgr;=9.2 (100); 2&thgr;=9.43 (68); 2&thgr;=9.82 (19). Contrary to the adducts of the present invention, which are characterized
Fait Anna
Govoni Gabriele
Sacchetti Mario
Basell Technology Company B.V.
Bell Mark L.
Bryan Cave LLP
Pasterczyk J.
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