Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2002-05-09
2004-05-25
Stoner, Kiley (Department: 1725)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S531000, C549S523000, C502S063000, C502S064000
Reexamination Certificate
active
06740764
ABSTRACT:
The present invention relates to an oxide which comprises the elements silicon and titanium and also comprises at least two different silicon dioxide phases of which one is noncrystalline and at least one is a crystalline phase having a zeolite structure, wherein the oxide contains no silicon-carbon bonds. The present invention likewise relates to a process for preparing this oxide and to the use of the oxide as catalyst.
Porous oxidic materials are used in a variety of technical and industrial processes. Particular mention may be made of oxides which have a zeolite structure. Preferred fields of application are, for example, catalytic processes in which these materials, inter alia, are used as catalyst.
In some of these processes, it is necessary for the acidity of the oxidic material, which is obtained as acidic material from particular production processes, to be reduced. At the same time, the material whose acidity has been reduced should be sufficiently stable for this acidity-modifying treatment not to have to be repeated after regeneration of the oxidic material.
U.S. Pat. No. 4,937,216 describes, for example, a catalyst for the epoxidation of olefins which comprises a synthetic zeolite of the formula xTiO
2
(1−x)SiO
2
. The surface of the catalyst used for the epoxidation bears Si—O—Si(R)
3
groups which result from reaction of a precursor of the catalyst with compounds of the structure X—Si—(R)
3
. A disadvantage of this procedure is that Si—C bonds are present in the catalyst used and these have such an adverse effect on the stability that the treatment with X—Si—(R)
3
compounds has to be repeated after one or more regeneration steps. Regeneration is, however, an important part of modem catalytic processes, since reuse of a catalyst is necessary from economic and ecological points of view. However, this regeneration is made difficult by insufficiently stable catalysts, so that the economic and ecological advantages are lost again.
U.S. Pat. No. 4,824,976 discloses a process for the epoxidation of olefins using the catalysts which are described in the above-discussed U.S. Pat. No. 4,937,216. Of course, this process also has the abovementioned disadvantages.
It is an object of the present invention to provide an oxide which does not have these disadvantages.
We have found that this object is achieved by an oxide comprising at least the elements Si and Ti, at least noncrystalline silicon dioxide and at least one crystalline silicate phase which has at least one zeolite structure, with noncrystalline silicon dioxide being applied to at least one crystalline silicate phase having at least one zeolite structure, wherein the oxide has no silicon-carbon bonds.
According to the present invention, the oxide can comprise one or more crystalline silicate phases each of which can have one or more zeolite structures. It is not necessary for the silicate phase or phases to be present exclusively in a zeolite structure. It is equally possible to conceive of a crystalline silicate phase which has not only one or more zeolite structures but also at least one further crystalline structure which is not a zeolite structure.
It is likewise conceivable for the oxide of the present invention to comprise at least one silicate phase which has at least one zeolite structure and at least one further silicate phase which is crystalline and has a structure which is not a zeolite structure.
Zeolites are, as is known, crystalline aluminosilicates having ordered channel and cage structures and containing micropores. For the purposes of the present invention, the term “micropores” corresponds to the definition in “Pure Appl. Chem.” 57 (1985) p. 603-619, and refers to pores having a pore diameter of less than 2 nm. The network of such zeolites is made up of SiO
4
and AlO
4
tetrahedra which are joined via shared oxygen bridges. An overview of known structures may be found, for example, in W. M. Meier, D. H. Olson and Ch. Baerlocher in “Atlas of Zeolite Structure Types”, Elsevier, 4th edition, London 1996.
In particular, there are zeolites which contain no aluminum and in which the Si(IV) in the silicate lattice is partly replaced by titanium as Ti(IV). Titanium zeolites, in particular those having a crystal structure of the MFI type, and possible ways of preparing them are described, for example, in EP-A 0 311 983 or EP-A 0 405 978.
Titanium zeolites having an MFI structure can be identified by means of a particular X-ray diffraction pattern and also by means of a lattice vibration band in the infrared region (IR) at about 960 cm
−1
and can in this way be distinguished from alkali metal titanates or crystalline and amorphous TiO
2
phases.
These are, in particular, titanium-, germanium-, tellurium-, vanadium-, chromium-, niobium-, zirconium-containing zeolites having a pentasil zeolite structure, especially the types assigned X-ray-crystalographically to the ABW, ACO, AEI, AEL, AEN, AET, AFG, AFI, AFN, AFO, AFR, AFS, AFT, AFX, AFY, AHT, ANA, APC, APD, AST, ATN, ATO, ATS, ATT, ATV, AWO, AWW, BEA, BIK, BOG, BPH, BRE, CAN, CAS, CFI, CGF, CGS, CHA, CHI, CLO, CON, CZP, DAC, DDR, DFO, DFT, DOH, DON, EAB, EDI, EMT, EPI, ERI, ESV, EUO, FAU, FER, GIS, GME, GOO, HEU, IFR, ISV, ITE, JBW, KFI, LAU, LEV, LIO, LOS, LOV, LTA, LTL, LTN, MAZ, MEI, MEL, MEP, MER, MFI, MFS, MON, MOR, MSO, MTF, MTN, MTT, MTW, MWW, NAT, NES, NON, OFF, OSI, PAR, PAU, PHI, RHO, RON, RSN, RTE, RTH, RUT, SAO, SAT, SBE, SBS, SBT, SFF, SGT, SOD, STF, STI, STT, TER, THO, TON, TSC, VET, VFI, VNI, VSV, WIE, WEN, YUG and ZON structures and to mixed structures made up of two or more of the abovementioned structures. Furthermore, titanium-containing zeolites having the ITQ-4, SSZ-24, TTM-1, UTD-1, CIT-1 or CIT-5 structure can also be used in the process of the present invention. Further titanium-containing zeolites which may be mentioned are those having the ZSM-48 or ZSM-12 structure.
Particularly preferred zeolites for the process of the present invention are Ti zeolites having an MFI, MEL or MFI/MEL mixed structure. More preferred are, specifically, the Ti-containing zeolite catalysts which are generally referred to as “TS-1”, TS-2”, “TS-3”, and also Ti zeolites having a lattice structure which is isomorphous with &bgr;-zeolite.
Furthermore, the oxide of the present invention can comprise titanium-containing zeolites having the UTD-1, CIT-1, CIT-5, MCM-22 or MCM-61 structure. Further titanium-containing zeolites which may be mentioned are those of the ZSM-48 or ZSM-12 structure. Such zeolites are described, inter alia, in U.S. Pat. No. 5,430,000 and WO 94/29408, whose relevant contents are hereby fully incorporated by reference into the present patent application. For the purposes of the present invention, particular preference is given to Ti zeolites having an MFI structure, an MEL structure or a mixed MFI/MEL structure. Preference is likewise given to Ti zeolites having a lattice structure which is isomorphous with &bgr;-zeolite.
Apart from silicon and titanium, additional elements such as aluminum, zirconium, vanadium, tin, zinc, iron, tellurium, niobium, tantalum, chromium, cobalt, nickel, gallium, germanium, boron or small amounts of fluorine can also be present in the crystalline silicate phase or phases having at least one zeolite structure.
Accordingly, thc present invention also provides an oxide as described above which comprises at least one element selected from the group consisting of Al, B, Fe, Ga, V, Zr, Gc, Sn, Zn, Te, Nb, Ta and Cr.
It is conceivable for, inter alia, one or more of these elements to be present in the above-described crystalline phase or phases having at least one zeolite structure. In particular, it is possible for one or more of these elements to be present in the zeolite structures themselves in this embodiment. However, it is of course also possible, in the case when this crystalline phase has not only the zeolite structure or structures but also at least one further crystalline structure which is not a zeolite structure, for at least one of these further structures to comprise at least one of t
Chen Yi
Chun Yuan
Ding Weiping
Lian Ma
Möller Ulrich
BASF - Aktiengesellschaft
Ildebrando Christina
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Stoner Kiley
LandOfFree
Oxide and method for production thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Oxide and method for production thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Oxide and method for production thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3207544