Catalyst – solid sorbent – or support therefor: product or process – Zeolite or clay – including gallium analogs – And additional al or si containing component
Reexamination Certificate
2000-03-27
2001-08-14
Truong, Duc (Department: 1711)
Catalyst, solid sorbent, or support therefor: product or process
Zeolite or clay, including gallium analogs
And additional al or si containing component
C502S080000, C528S486000, C528S401000, C528S354000
Reexamination Certificate
active
06274527
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates in general to the polymerization of certain monomers and more specifically to the use of Maghnia and Mostaganem bentonites as catalysts for polymerization.
BACKGROUND OF THE INVENTION
The present field of polymerization of monomers is varied in types of monomers, catalysts, and processes. Often, catalysts used to make polymers are expensive, may be poisoned by products of the reaction or impurities present in the monomer feed, and contain heavy metals such as chromium, mercury and cadmium that present environmental disposal problems for users. Frequently, these catalysts require the use of very high or very low temperatures and high pressures during the polymerization reaction. Separation of the catalyst from the polymer is not always possible, making the polymer less desirable for the customer.
Examples of these problems are found in the polymerization of tetrahydrofuran (THF) and dioxolane (DXL). The cationic polymerization of THF is now mostly catalyzed with a BF
3
/FSO
3
H/HClO
4
mixture, or oleum. This reaction requires a promoter, typically an olefin oxide, acetyl chloride, acetic anhydride or cetene. Because of the inefficiency of the catalyst, large amounts of the catalyst and promoter are required, up to one mole of catalyst for one mole of polytetrahydrofuran (PTHF), resulting in a very expensive process. Similarly, DXL is most often polymerized using a BF
3
/FSO
3
H mixture in the presence of dichloromethane in a nitrogen atmosphere. However, the reaction is not continuous, the yield is poor, and purification of the product from the residual BF
3
is difficult. As a result of these problems, polydioxolane is not manufactured on an industrial scale.
The chemical industry is always looking for new substitutes to these classical catalysts. For instance, PTHF can now be polymerized in a cost-effective and environmentally appropriate manner using antimony pentachloride as a catalyst and a mixture of carboxylic anhydrides in the presence of alcohol as a promoter. But while this new manner of catalysis has alleviated some of the processing problems, it has resulted in a polymer that, because of its black color, does not meet industry needs.
In addition, toxic catalysts often present problems in the manufacture of polymers used in medical and veterinary procedures. Those installing these polymers often desire that the polymer be metabolized by the body after the polymer has performed its function. These types of polymers are called “bioresorbable.” Many bioresorbable polymers are synthesized from lactides. These bioresorbable polymers are frequently used for suture strings, suture wire, staples, meshes, and hemostatic clamps. The polylactide are synthesized with the use of catalysts, most often a trioxide of antimony and stannous octanoate. These catalysts are toxic in even trace amounts, necessitating a careful and costly separation of the catalyst from the polymer.
SUMMARY OF THE INVENTION
Accordingly, there is a need for an effective, low-operating-cost, environmentally-appropriate method of polymerizing certain monomers. We have found that activated Algerian bentonites, particularly those from Maghnia or Mostaganem, at temperatures between 0° and 80° C. are capable of catalyzing the polymerization of these monomers. The bentonite catalyst is activated by contacting a Maghnia or Mostaganem bentonite with an acid solution of selected concentration and then drying the Maghnia or Mostaganem bentonite.
In another embodiment of the invention, a vinyl, acrylic, cyclic ether, aldehyde, lactone or olefin monomer is polymerized by contacting a Maghnia or Mostaganem bentonite with an acid solution of selected concentration, drying the Maghnia or Mostaganem bentonite and then contacting the vinyl, acrylic, cyclic ether, aldehyde, lactone, or olefin monomer with the Maghnia or Mostaganem bentonite.
In another embodiment of the invention, a polymer is manufactured by contacting a Maghnia or Mostaganem bentonite with an acid solution of selected concentration, then drying the Maghnia or Mostaganem bentonite and contacting a vinyl, cyclic ether, aldehyde, lactone, acrylic or olefin monomer with the Maghnia or Mostaganem bentonite.
In a further embodiment of the invention, a perflourinated amine or diamine is synthesized by contacting a Maghnia or Mostaganem bentonite with an acid solution of selected concentration, drying the Maghnia or Mostaganem bentonite, and adsorbing a secondary amine with the Maghnia or Mostaganem bentonite to form a perflouroamide iodide salt. The perflouramide idodide salt can then be extracted with a polar solvent and neutralized by the use of a basic solution.
One advantage of the present invention is that the Maghnia or Mostaganem bentonite can be easily activated with a variety of mineral or organic acids, at room temperature or under heat with a simple procedure. As another advantage, these catalysts can then initiate polymerization and copolymerization reactions at relatively low temperatures. As a further advantage, the catalysts can be regenerated easily, requiring only heating to a temperature above 100° C. As an additional advantage, the catalysts can be easily separated from the polymer product for reuse, reducing operating costs as well as disposal costs.
DETAILED DESCRIPTION OF THE INVENTION
Bentonites are hydrated aluminosilicates which crystallize in layers. These bentonites occur naturally and are mined by the National Company of Non-Ferreous Products (Enterprise Nationale des produits non ferreux, ENOF). After crushing, bentonites can be sold under the name of “load bentonite.” Once crushed, activated in hot sulfuric acid (32%-38% in weight), dried, ground, sifted and conditioned, bentonites are commercialized under the name of “bleaching clay.” Bentonites are often used to filter cooking, mineral, and organic oils. When added to calcium carbonates, but not acid-treated, bentonites are used for oil drilling under the name of “drilling bentonite.” Bentonites are often utilized as bleaching clays for oils, drilling mud for oil drilling, as stabilizer for paints and rubbers, and as insulators for foundries. However, use of bentonites as catalysts is very new, and research and patenting has been limited to bentonites found in the United States, with focus on those found in Wyoming and Texas. The Algerian bentonites do not have the same physical and chemical structure as the American bentonites and prior to this invention, were never tested for their catalytic properties. FIG. 1 is a comparison of the composition of American, French and Maghnia Algerian bentonites.
FIG.
1
Comparison of the Composition (in %) of American, French,
and Maghnia Algerian Bentonites
(Prior to Treatment)
Wyoming
Vienne
Maghnia
Maghnia
(USA)
(France)
(Algeria)
(Algeria)
SiO2
57.4
50.04
69.39
71.7
Al2O3
20.27
20.16
14.67
14.03
Fe2O3
2.92
0.68
1.16
0.71
FeO
0.19
9
CaO
0.23
1.46
0.3
0.28
MgO
3.13
.23
1.07
0.8
K2O
0.28
1.27
0.79
0.77
Na2O
1.32
trace
0.5
0.21
TiO2
0.12
0.16
0.15
SO3
0.91
0.34
As
0.05
0.01
Organics/Water
11
11
H2O
6.85
26
Bentonite from Maghnia has 11.9% more SiO
2
than that from Wyoming and 19.35% more than from Montmorillon (Vienne, France). When treated with sulfuric acid, this difference is even greater: 14.21% and 21.66% as compared to Wyoming and Vienne bentonites, respectively.
Bentonite from Maghnia contains 5.60% and 5.49% less A1
2
O
3
than the Wyoming and Vienne bentonites, respectively. Once treated, this difference is 6.24% and 6.13% with respect to the Wyoming and Vienne bentonites, respectively. The X-ray diffraction spectra from the 3 bentonites are comparable except the peak intensities and the width of the interlayer spacing which varies with the chemical composition. However, bands at 3.76, 3.05, 2.97, 2.12, 1.83 Å observed in the spectrum of the Wyoming bentonite are not present in the spectrum of the bentonite from Maghnia. The same main IR bands are observed in the bentonites from Texas, Wyoming, and Maghnia with some variations. However, the bands at 885 cm
−1
Belbachir Mohammed
Bensaoula Abdelhak
Baker & Botts L.L.P.
Truong Duc
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