Chemistry of hydrocarbon compounds – Aromatic compound synthesis – By condensation of entire molecules or entire hydrocarbyl...
Reexamination Certificate
1999-09-01
2001-06-19
Griffin, Walter D. (Department: 1764)
Chemistry of hydrocarbon compounds
Aromatic compound synthesis
By condensation of entire molecules or entire hydrocarbyl...
C585S456000, C585S463000, C585S464000, C502S159000, C502S402000
Reexamination Certificate
active
06248930
ABSTRACT:
FIELD OF THE INVENTION
This invention concerns catalysts comprising chemically modified perfluorinated ion-exchange microcomposites, processes for their preparation and their use as catalysts in chemical processes.
TECHNICAL BACKGROUND
K. A. Mauritz et al., Polym. Mater. Sci. Eng. 58, 1079-1082 (1988), in an article titled “Nafion-based Microcomposites: Silicon Oxide-filled Membranes”, discuss the formation of micro composite membranes by the growth of silicon oxide microclusters or continuous silicon oxide interpenetrating networks in pre-swollen “NAFION®” sulfonic acid films. NAFION® is a registered trademark of E. I. du Pont de Nemours and Company.
U.S. Pat. No. 4,038,213 discloses the preparation of catalysts comprising perfluorinated ion-exchange polymers containing pendant sulfonic acid groups on a variety of supports.
The catalyst utility of perfluorinated ion-exchange polymers containing pendant sulfonic acid groups, supported and unsupported has been broadly reviewed: G. A. Olah et al., Synthesis, 513-531 (1986) and F. J. Waller, Catal. Rev.-Sci. Eng., 1-12 (1986).
WO 95/19222 describes a porous microcomposite comprising a perfluorinated ion-exchange microcomposite containing pendant sulfonic acid and/or carboxylic acid groups entrapped within and highly dispersed throughout a network of metal oxide. These catalysts are differentiated from NAFION® supported catalysts in that by virtue of the preparation of the microcomposite catalyst, the polymer, in solution, becomes intimately mixed with a metal oxide network precursor in solution, and thus becomes thoroughly entrapped and highly dispersed throughout a resulting network of metal oxide. With the polymer being mechanically entrapped within the metal oxide network and not merely on the surface of a support, as is the case in supported catalysts, the catalytic activity of these microcomposites is significantly increased.
Although a variety of reactions can be beneficially catalyzed by the compounds and the composites cited above, there is still a need for catalysts of increased activity and selectivity and broader applications.
SUMMARY OF THE INVENTION
The present invention provides a fluorine-modified porous microcomposite, comprising: a perfluorinated ion-exchange polymer containing pendant sulfonic acid groups and/or pendant carboxylic acid groups, wherein the polymer is entrapped within and highly dispersed throughout a network of inorganic oxide, said network having a plurality of fluoride atoms bonded thereto.
The present invention also provides a process for the preparation of a fluorine-modified porous microcomposite, comprising: contacting a porous microcomposite comprising a perfluorinated ion-exchange polymer containing pendant sulfonic acid groups and/or carboxylic acid groups, wherein said polymer is entrapped within and highly dispersed throughout a network of inorganic oxide, with an effective amount of a fluorinating agent under fluorinating conditions whereby a plurality of hydroxyl groups of the inorganic oxide network are replaced by fluoride groups.
The present invention further provides a method of alkylating an aromatic compound, the improvement comprising using an effective amount of a catalyst composition comprising a fluorine-modified porous microcomposite comprising a perfluorinated ion-exchange polymer containing pendant sulfonic acid groups and/or pendant carboxylic acid groups, wherein the polymer is entrapped within and highly dispersed throughout a network of inorganic oxide, said network having a plurality of fluoride groups bonded thereto.
DETAILED DESCRIPTION OF THE INVENTION
The present invention concerns the modification of a porous microcomposite. By “porous microcomposite” is meant a composition comprising a perfluorinated ion-exchange polymer (PFIEP) containing pendant sulfonic acid groups and/or pendant carboxylic acid groups, wherein said polymer is entrapped within and highly dispersed throughout a network of inorganic oxide. The percentage of the perfluorinated ion-exchange polymer in the microcomposite is from 0.1 to about 90% by weight and the size of the pores in the microcomposite is about 1 nm to about 75 nm, and the microcomposite optionally further comprises pores having a size in the range of about 75 nm to about 1000 nm. Such microcomposites are described in U.S. application Ser. No. 08/574,571 incorporated by reference herein and in a corresponding PCT publication WO 95/19222. The microcomposite can be in any size or shape to be utilized in the present invention, such as ground into particles or shaped into spheres. The PFIEP preferably contains pendant sulfonic acid groups, and is most preferably, a sulfonated NAFION® PFIEP. The weight percentage of PFIEP preferably ranges from about 5% to about 80%, most preferably from about 10% to about 15%. The inorganic oxide of the network is preferably silica, alumina, titania, germania, zirconia, alumino-silicate, zirconyl-silicate, chromic oxide, iron oxide, or mixtures thereof; most preferably silica.
The inorganic oxide network of the present fluorine-modified porous microcomposite has a plurality of fluoride groups bonded thereto. By “having a plurality of fluoride groups bonded thereto” is meant that a portion of the hydroxyl groups of the inorganic oxide network, preferably at least 50% of the hydroxyl groups, most preferably at least 80% of the hydroxyl groups, are replaced by a fluoride group via reaction with a fluorinating agent, and each fluoride group is bonded to the inorganic oxide network. As is known, after formation of an inorganic oxide network, there are numerous residual hydroxyl groups. This is because during network formation each of the inorganic atoms become constituents of a network structure via bonds to other inorganic atoms through oxygen but condensation to form these crosslinks does not go to 100% completion; there are residual, uncrosslinked hydroxyl groups. For example, in the present case where the inorganic oxide of the network in the microcomposite is silica, silanol (Si—OH) groups can be found as part of the network, and it is a plurality of the hydroxyl (—OH) groups of these silanols that are converted to fluoride groups which are bonded to the network.
Preferably the fluorine-modified microcomposite comprises an inorganic oxide network wherein the inorganic oxide is silica, and the entrapped and highly dispersed PFIEP contains pendant sulfonic acid groups
The present invention also provides a process for the preparation of a fluorine-modified porous microcomposite, comprising: contacting a porous microcomposite comprising a perfluorinated ion-exchange polymer containing pendant sulfonic acid groups and/or carboxylic acid groups, wherein said polymer is entrapped within and highly dispersed throughout a network of inorganic oxide, with an effective amount of a fluorinating agent under fluorinating conditions whereby a plurality of hydroxyl groups of the inorganic oxide network are replaced by fluoride groups.
In the present process, a porous microcomposite, as described above, is contacted with a fluorinating agent. By “fluorinating agent” is meant a reagent capable of reacting with a plurality of the hydroxyl groups of the inorganic oxide network to generate bonded fluoride groups. Preferably the fluorinating agent comprises a reagent selected from the group consisting of: hydrofluoric acid, a mixture of hydrogen fluoride and pyridine, ammonium fluoride, fluorine and a compound having a group of the formula R
1
R
2
R
3
N
+
-fluorine, wherein each R
1
, R
2
and R
3
are independently selected from an aliphatic or ring hydrocarbon. It may be desirable for the fluorinating agent to further comprise an organic solvent and/or an organic base. In some cases the solvent and the base functions can be satisfied by the same compound. Representative examples of basic organic solvents are pyridine, trimethylpyridine and the like.
By “fluorinating conditions” is meant those conditions necessary to replace a hydroxyl group of the inorganic oxide network with a fluoride group. For certain reagen
Harmer Mark Andrew
Sun Qun
E. I. Du Pont de Nemours and Company
Griffin Walter D.
LandOfFree
Fluorine-modified perfluorinated ion-exchange microcomposite... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fluorine-modified perfluorinated ion-exchange microcomposite..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluorine-modified perfluorinated ion-exchange microcomposite... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2539877