Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
2003-03-18
2004-04-20
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C423S277000, C423S718000, C502S077000
Reexamination Certificate
active
06723862
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to the isomerization of fatty acids with a strongly acidic and hydrothermally stable mesoporous aluminosilicate catalyst.
BACKGROUND OF THE INVENTION
Fatty acids are the building blocks for various compositions ranging from lubricants, polymers, solvents, cosmetics and the like. Fatty acids are generally obtained by hydrolysis of triglycerides of vegetable or animal origin. Naturally occurring triglycerides are esters of glycerol and generally straight chain, even numbered carboxylic acids, in size ranging from 10-24 carbon atoms. Most common are fatty acids having 12, 14, 16 or 18 carbon atoms. The fatty acids are either saturated or contain one or more unsaturated bonds.
Long, straight chain saturated fatty acids (C10:0 and higher) are solid at room temperature, which makes them difficult to process in a number of applications. Unsaturated long chain fatty acids, however, e.g. oleic acid are liquid at room temperature, so are easy to process, but are unstable because of the existence of double bond(s). Branched fatty acids mimic the properties of the straight chain unsaturated fatty acids in many respects, but do not have the disadvantage of being unstable. “Branched fatty acids” means fatty acids containing one or more alkyl side groups which are attached to the carbon chain backbone at any position. Therefore, branched fatty acids are for many applications more desirable than straight chain fatty acids. Commercial branched acids are not, however, naturally occurring materials.
Currently, branched fatty acids are obtained by isomerization (branching) of the straight chain, unsaturated fatty acids having a corresponding chain length. For example, branched C18:0 is prepared from straight C18:1 (or also C18:2). Various routes are known for said isomerization or branching of fatty acids in the art.
Porous inorganic solids have found great utility as catalysts and separations media for various industrial applications. The openness of their microstructure allows molecules to access the relatively large surface areas of these materials that enhance their catalytic and sorptive activity. Three broad categories of microporous materials are in use today. These categories, which employ details of their microstructure as a basis for classification, are the i) amorphous and paracrystalline solids, ii) the crystalline molecular sieves and iii) layered materials. The detailed differences in the microstructures of these materials manifest themselves as important differences in the catalytic and sorptive behavior of the materials, as well as in differences in properties used to characterize them, such as their surface area, composition, acidity, basicity, the sizes of pores and the variability in those sizes, the presence or absence of X-ray diffraction patterns and the details in such patterns, and the appearance of the materials when their microstructure is studied by transmission electron microscopy, infrared absorption, electron diffraction methods.
Amorphous and paracrystalline materials represent an important class of porous inorganic solids that have been used for many years in industrial applications. Typical examples of these materials are the amorphous silicas commonly used in catalyst formulations and the paracrystalline transitional aluminas used as solid acid catalysts and petroleum reforming catalyst supports. The term “amorphous” is used here to indicate a material with no long range order and can be somewhat misleading, since almost all materials are ordered to some degree, at least on the local scale. An alternate term that has been used to describe these materials is “X-ray indifferent”.
Paracrystalline materials such as the transitional aluminas also have a wide distribution of pore sizes, but better defined X-ray diffraction patterns usually consisting of a few broad peaks. The microstructure of these materials consists of tiny crystalline regions of condensed alumina phases and the porosity of the materials results from irregular voids between these regions. Since, in the case of either material, there is no long range order controlling the sizes of pores in the material, the variability in pore size is typicaly quite high. The sizes of pores in these materials fall into a regime called the mesoporous range, which is generally in the range of from about 13 to 200 Angstroms.
In sharp contrast to these structurally ill-defined solids are materials whose pore size distribution is very narrow because it is controlled by the precisely repeating crystalline nature of the materials' microstructure. These materials are called “molecular sieves”, the most important examples of which are zeolites. The pore/channel openings of typical zeolites ranges from 3-7.5 angstroms, although larger sizes have been reported.
Finally, layered materials contain layers capable of being spaced apart with a swelling agent, and may be pillared to provide materials having a large degree of porosity. Examples of such layered materials include clays. Such clays may be swollen with water, whereby the layers of the clay are spaced apart by water molecules. Other layered materials are not swellable with water, but may be swollen with certain organic swelling agents such as amines and quaternary ammonium compounds. Examples of such non-water swellable, layered materials include, but are not limited to, layered silicates, magadiite, kenyaite, trititanates and perovskites. Another example of a non-water swellable layered material, which can be swollen with certain organic swelling agents, is a vacancy-containing titanometallate material, as described in U.S. Pat. No. 4,831,006. Once a layered material is swollen, the material may be pillared by interposing a thermally stable substance, such as silica, between the spaced apart layers. Various pillaring materials and methods for pillaring water swellable and non-water swellable layered materials described therein and are known in the art.
Each of these materials does, however, have its limitations. Despite encouraging progress in recent years concerning amorphous and paracrystalline materials, both the acidity and hydrothermal stability at higher temperatures of the current materials are generally lower than those of microporous aluminosilicate zeolites. Crystalline microporous zeolites are very stable, can be made to have strong acidity, and are widely used commercially. However, their applications are limited due to their relatively small channel diameter. Finally, clay catalyzed isomerization suffers from two main disadvantages. First, a considerable amount of undesired side products containing oligomers, saturated straight chain fatty acids and intermediate dimers is formed. A second disadvantage is that the clay catalyst cannot be reused. Accordingly, processes which employ these materials for the preparation of branched fatty acids from straight chain unsaturated fatty acid feedstocks are typically plagued by low yield, undesireable byproduct formation and premature catalyst deactivation.
The present invention has solved many of the problems of the prior art by utilizing a catalyst having the positive attributes of both mesoporous and microporous type catalytic materials.
SUMMARY OF THE INVENTION
The present invention generally relates to a process for the preparation of branched fatty acids from straight chain unsaturated fatty acid feedstocks with a strongly acidic and hydrothermally stable mesoporous aluminosilicate and aluminophosphate catalyst materials having mesopores of 15-500 Å and contain primary and secondary nanosized zeolite structural units in the walls that separate mesopores.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention generally relates to a process for the preparation of branched fatty acids from straight chain unsaturated fatty acid feedstocks with a strongly acidic and hydrothermally stable mesoporous aluminosilicate and aluminophosphate catalyst materials having mesopores of 15-500 Å and contain primary and secondary nanosized zeo
Shuguang Zhang
Zongchao Zhang
Akzo Nobel N.V.
Carr Deborah D.
Mancini Ralph J.
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