423 results about "Olefin metathesis" patented technology

The invention provides novel organometallic complexes useful as olefin metathesis catalysts. The complexes have an N-heterocyclic carbene ligand and a chelating carbene ligand associated with a Group 8 transition metal center. The molecular structure of the complexes can be altered so as to provide a substantial latency period. The complexes are particularly useful in catalyzing ring closing metathesis of acyclic olefins and ring opening metathesis polymerization of cyclic olefins.

This invention relates generally to olefin metathesis, and more particularly relates to the ring-opening, ring insertion cross-metathesis of cyclic olefins with internal olefins such as seed oils and the like. In one embodiment, a method is provided for carrying out a catalytic ring-opening cross-metathesis reaction, comprising contacting at least one olefinic substrate with at least one cyclic olefin as a cross metathesis partner, in the presence of a ruthenium alkylidene olefin metathesis catalyst under conditions effective to allow ring insertion cross metathesis whereby the cyclic olefin is simultaneously opened and inserted into the olefinic substrate. The invention has utility in the fields of catalysis, organic synthesis, and industrial chemistry.

This invention relates generally to olefin metathesis, and more particularly relates to the synthesis of terminal alkenes from internal alkenes using a cross-metathesis reaction catalyzed by a selected olefin metathesis catalyst. In one embodiment of the invention, for example, a method is provided for synthesizing a terminal olefin, the method comprising contacting an olefinic substrate comprised of at least one internal olefin with ethylene, in the presence of a metathesis catalyst, wherein the catalyst is present in an amount that is less than about 1000 ppm relative to the olefinic substrate, and wherein the metathesis catalyst has the structure of formula (II) wherein the various substituents are as defined herein. The invention has utility, for example, in the fields of catalysis, organic synthesis, and industrial chemistry.

The present invention provides methods for the synthesis of catalysts and precursors thereof. Methods of the invention may comprise combining a catalyst precursor and at least one ligand to generate a catalytically active species, often under mild conditions and in high yields. In some cases, a wide variety of catalysts may be synthesized from a single catalyst precursor. Methods of the invention may also include the preparation of catalysts which, under reaction conditions known in the art, may have been difficult or impossible to prepare and / or isolate due to, for example, steric crowding at the metal center. The present invention also provides catalyst compositions, and precursors thereof, which may be useful in various chemical reactions including olefin metathesis. In some cases, methods of the invention may reduce the number of synthetic and purification steps required to produce catalysts and / or other reaction products, as well as reducing time, cost, and waste production.

Processes for producing hydrocarbons in the gasoline and jet fuel range. The processes involve the thermal decarboxylation of fatty acids, which can be derived from the hydrolysis of triglycerides, which triglycerides can be vegetable oils, animal fats, or combinations thereof. The resulting hydrocarbons can be hydrocracked, and, optionally, isomerized and / or hydrotreated, to yield hydrocarbons in the jet fuel or gasoline range. Where the resulting hydrocarbons include olefinic double bonds, they can alternatively be combined with low molecular weight olefins, and subjected to olefin metathesis to yield hydrocarbons in the jet fuel or gasoline range.

Organometallic complexes suitable as olefin metathesis catalysts are provided. The complexes are Group 8 transition metal carbenes bearing a cationic substituent and having the general structure (I)wherein M is a Group 8 transition metal, L1 and L2 are neutral electron donor ligands, X1 and X2 are anionic ligands, m is zero or 1, n is zero or 1, and R1, W, Y, and Z are as defined herein. Methods for synthesizing the complexes are also provided, as are methods for using the complexes as olefin metathesis catalysts.

The present invention relates generally to catalysts and processes for the Z-selective formation of internal olefin(s) from terminal olefin(s) via homo-metathesis reactions.

Improved catalysts useful in alkyne or olefin metathesis are made by bringing into contact a multi-coordinated metal complex comprising a multidentate Schiff base ligand, and one or more other ligands, with a selected activating compound under conditions such that at least partial cleavage of a bond between the metal and the multidentate Schiff base ligand of said metal complex occurs.

The present invention relates to the use of isomerization inhibitors in olefin metathesis reactions. The inhibitors are low molecular weight organic acids such as formic acid, acetic acid, benzoic acid, and the like.

The present invention provides methods for the synthesis of catalysts and precursors thereof. Methods of the invention may comprise combining a catalyst precursor and at least one ligand to generate a catalytically active species, often under mild conditions and in high yields. In some cases, a wide variety of catalysts may be synthesized from a single catalyst precursor. Methods of the invention may also include the preparation of catalysts which, under reaction conditions known in the art, may have been difficult or impossible to prepare and / or isolate due to, for example, steric crowding at the metal center. The present invention also provides catalyst compositions, and precursors thereof, which may be useful in various chemical reactions including olefin metathesis. In some cases, methods of the invention may reduce the number of synthetic and purification steps required to produce catalysts and / or other reaction products, as well as reducing time, cost, and waste production.

This invention relates to a process to functionalize propylene co-oligomer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene, and a propylene a co-oligomer having an Mn of 300 to 30,000 g / mol comprising 10 to 90 mol % propylene and 10 to 90 mol % of ethylene, wherein the oligomer has at least X % allyl chain ends, where: 1) X=(−0.94 (mol % ethylene incorporated)+100), when 10 to 60 mol % ethylene is present in the co-oligomer, and 2) X=45, when greater than 60 and less than 70 mol % ethylene is present in the co-oligomer, and 3) X=(1.83*(mol % ethylene incorporated)−83), when 70 to 90 mol % ethylene is present in the co-oligomer. This invention also relates to a process to functionalize propylene homo-oligomer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene, and a propylene homo-oligomer, comprising propylene, wherein the oligomer has: at least 93% allyl chain ends, an Mn of about 500 to about 20,000 g / mol, an isobutyl chain end to allylic vinyl group ratio of 0.8:1 to 1.2:1.0, and less than 100 ppm aluminum.

The present invention provides a new type of alpha-helix nucleating cross-link (“staple”) formed by olefin metathesis of a proline derivative with an alkenyl side chain and another amino acid derivative with an alkenyl side chain. The proline derivatives as described herein have been found to be strong nucleators of alpha-helix formation. The invention also provides moieties for shielding the free amide N—H's at the N-terminus of an alpha-helix, thereby further stabilizing the helix. The proline derivatives, precursors prior to cross-linking, and the cross-linked peptides are provided as well as methods of using and preparing these compounds and peptides.

This invention relates generally to olefin metathesis, and more particularly relates to the synthesis of terminal alkenes from internal alkenes using a cross-metathesis reaction catalyzed by a selected olefin metathesis catalyst. In one embodiment of the invention, for example, a method is provided for synthesizing a terminal olefin, the method comprising contacting an olefinic substrate comprised of at least one internal olefin with ethylene, in the presence of a metathesis catalyst, wherein the catalyst is present in an amount that is less than about 1000 ppm relative to the olefinic substrate, and wherein the metathesis catalyst has the structure of formula (II)wherein the various substituents are as defined herein. The invention has utility, for example, in the fields of catalysis, organic synthesis, and industrial chemistry.

The invention relates to immobilisable ruthenium catalysts containing N-heterocyclic carbene ligands of the general formulae (I) and (II) which contain an SiR′n(OR′)3 -carrying group on one of the two nitrogen atoms of the NHC ligand, and to the use thereof as homogeneous catalysts in C-C coupling reactions, in particular olefin metathesis. The invention furthermore relates to the use of the compounds as starting materials for the preparation of analogous immobilised ruthenium catalysts containing N-heterocyclic carbene ligands.

A process of stabilizing an olefin metathesis product mixture, preferably, against double bond isomerization and thermal and chemical degradation. The process involves (a) contacting an olefin metathesis product mixture comprising one or more olefins produced in a metathesis process, a metathesis catalyst comprising a catalytic metal and one or more ligands, optionally, one or more metathesis catalyst degradation products, and optionally, one or more metals derived from sources other than the catalyst or catalyst degradation product(s), with an adsorbent, more preferably carbon; or alternatively, (b) subjecting the olefin metathesis product mixture to a two-step distillation, preferably, including short path wiped-film evaporation. A stabilized olefin metathesis product mixture is disclosed containing one or more olefins obtained in a metathesis process and having a total concentration of metal(s) of less than about 30 parts per million by weight.