The invention therefore relates to the use of these metal complexes dispersed and grafted onto the solid oxide in the manufacture of a metathesis catalyst of alkanes. May optionally provide for the separation between upper and lower alkanes, alkanes, for example for the purpose of recycling the lower alkane or higher alkanes.
The method of claim 11, characterized in that the catalyst is a tantalum hydride, tungsten or chromium grafted onto silica or silica-alumina. Silica-supported tungsten carbyne complexes have shown high Turn Over Numbers TONs without generating significant alkyne metathesis products [ 4 ].
Turnover numbers were calculated for each aliquot. The metathesis reaction of linear alkanes, branched or cyclic substituted is preferably carried out by passing the alkane in the gas phase over the solid catalyst; the gas phase reaction can be conducted at atmospheric pressure or above but at a pressure less than or equal to the condensation pressure of the alkane or isolated of the heaviest alkane when there are several starting alkanes.
In this reaction, saturated hydrocarbons, linear and branched, were rearranged to longer or shorter paraffins. In some embodiments such production involves the partial oxidation of the carbonacous or organic material at elevated temperatures, and optionally elevated pressures, with a limited volume of oxygen, the reaction preferably being carried out in a reactor into which the material is fed, together with additional agents such as steam, carbon dioxide, or various other materials.
Moreover, tungsten hydride exhibits a specific ability in the transformation of isobutane into 2,3-dimethylbutane as well as in the metathesis of olefins or the selective transformation of ethylene into propylene.
The three principal products C9, C10 and C11 are found in a 1: Alkane metathesis is a novel catalytic and direct transformation of two molecules of a given alkane into its lower and higher homologues; moreover, the process proceeds at relatively low temperature ambient conditions or higher.
Organometallics8, In some embodiments, the metathesis catalyst is at least one of, or a mixture of, molybdic acid, ruthenium trichloride, ruthenium trichloride trihydrate, ruthenium tribromide, ruthenium triiodide, tungsten hexachloride, tungsten hexabromide, tungsten hexaiodide, molybdenum chloride, molybdenum bromide, molybdenum iodide, ruthenium oxide, tungsten oxide, tantalum chloride, tantalum bromide, tantalum iodide, tantalum oxide, a tetraalkyl or tetraaryltin complex of a tungsten halide, molybdenum halide, tantalum halide, rhenium halide, ruthenium halide, molybdenum oxide such as a lithium aluminum hydryde activated molybdenum oxide, rhenium oxide, cobalt oxide include cobalt oxide-molybdenum oxide, rhenium pentachloride, rhenium pentabromide, rhenium pentaiodide, trialkyl aluminum and dialkyl aluminum chloride complexes of rhodium halides, tungsten halide, molybdenum halide, ruthenium halide.
The reverse reaction of CM of two alpha-olefins, ethenolysiscan be favored but Alkane metathesis high pressures of ethylene to increase ethylene concentration in solution.
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The reaction may be a homogeneous reaction that is, the catalysts free of a support or a heterogeneous reaction that is, the catalysts coupled to or immobilized on a solid supportagain in accordance with known techniques.
Mention may in particular work under a pressure of between 10 "2 and bar, preferably at atmospheric pressure. In any of the pairwise mechanisms with olefin pairing as rate-determining step this compound, a secondary reaction product of C12 with C6, would form well after formation of the two primary reaction products C12 and C When included, any suitable hydrogen acceptor can be used.
In a method of making a liquid hydrocarbon fuel from a synthesis gas by the Fischer-Tropsch reaction, wherein said fuel comprises at least one high molecular weigh alkane, wherein at least a portion of the product of said Fischer Tropsch reaction comprises a wax, and wherein said wax is of still higher molecular weight than said high molecular weight alkane, the improvement comprising: The surface should be considered as a bulky rigid ligand preventing most undesired interferences between catalytic sites e.
The Thorpe—Ingold effect may also be exploited to improve both reaction rates and product selectivity. We shall review here some of the recent catalytic results obtained on oxides. Search articles by author.
Thus the performance of these known reactions approval of alkanes remain very modest or linked to a process of flavoring. In some embodiments olefin hydrogen acceptors are preferred. Triphenylsiloxide and variations have been Tsang, W. The reaction may also be effected in the presence of an inert gas such as preferably nitrogen, helium or argon.
In other embodiments the first alkane is of a still higher molecular weight e. A method according to claim 5 or 6, characterized in that the grafting reaction is conducted at a temperature greater than or equal to room temperature.
First, different that process has been obtained in AM systems. XX is the XXth reference in the list of references. In Casey was the first to implement carbenes into the metathesis reaction mechanism: Alkane metathesis represents a powerful tool for making progress in a variety of areas, perhaps most notably in the petroleum and petrochemical fields.
The disclosures of all United States patents cited herein are to be incorporated herein by reference in their entirety. The method may further be applied to cyclic hydrocarbons compounds with one or more ringsfor example aromatic or saturated rings, substituted by at least one linear or branched alkane.
Since Mo and W catalysts of this type 2- trifluoromethyl phenyl imido and adamantylimido ligands, are modular,8 and since new catalysts have been discovered respectively, instead of a 2,6-diisopropylphenyl imido ligand. An apparatus for carrying out a method of the invention is schematically illustrated in FIG.
Ammonium perrhenate was purchased from Aldrich and used as received. Other examples are iridium catalysts, including but not limited to those described in U. It is well known that the commonly called paraffins alkanes molecules are difficult to process because of their chemical inertness.
The method of claim 1, wherein said metathesis catalyst is selected from the group consisting of Schrock catalysts. Alkane Metathesis Project Details The ability to convert low-molecular-weight alkanes to high-molecular-weight alkanes yields additional.
In addition to the metathesis of strained cyclic and exocyclic oleﬁns, the remarkable functional group tolerance (alcohols, aldehydes, carboxylic acids) and stability toward air, water. SOMC has allowed the discovery of new catalytic reactions (e.g.
Ziegler-Natta depolymerization, alkane metathesis, non-oxidative methane coupling, cyclo-alkane metathesis, etc.) and has improved the activity, the selectivity or the lifetime of known ones. Alkane metathesis is a novel catalytic and direct transformation of two molecules of a given alkane into its lower and higher homologues; moreover, the process proceeds at relatively low temperature (ambient conditions or higher).
The optimum conditions of alkylation are: temperature /sup 0/C; phenol/olefin molar ratio ; catalyst KY-2 in H-form, 25macrocyclization through an olefin metathesis/hydrogenation sequenceSubsequent sequential double olefin metathesis/hydrogenation reactions employingmacrocyclization through an olefin metathesis/hydrogenation sequence.
analysis og. Alkane Synthesis Using Organocopper Reagents - In crossed-olefin metathesis, one alkene is converted to a mixture of two new alkenes. Olefin Metathesis. Olefin Metathesis. The reaction is generally catalyzed a transition | PowerPoint PPT presentation | free to view.Alkane metathesis