418 results about "Olefin metathesis" patented technology

The present invention relates to an olefin metathesis reaction catalyst where rhenium (Re) oxide or molybdenum (Mo) oxide is supported, as a catalyst main component, on a surface-modified mesoporous silica or mesoporous alumina support, and a preparation method therefor. The olefin metathesis reaction catalyst of the present invention allows highly efficient metathesis of long-chain unsaturated hydrocarbons having at least eight carbons at a low temperature of 150° C. or lower. The catalyst can be separated readily from reaction solution, regenerated at a low temperature of 400° C. or lower by removing toxins accumulated on it during the metathesis reaction, and used repeatedly in metathesis reaction many times, thereby being made good use in commercial olefin metathesis processes.

Chelating ligand precursors for the preparation of olefin metathesis catalysts are disclosed. The resulting catalysts are air stable monomeric species capable of promoting various metathesis reactions efficiently, which can be recovered from the reaction mixture and reused. Internal olefin compounds, specifically beta-substituted styrenes, are used as ligand precursors. Compared to terminal olefin compounds such as unsubstituted styrenes, the beta-substituted styrenes are easier and less costly to prepare, and more stable since they are less prone to spontaneous polymerization. Methods of preparing chelating-carbene metathesis catalysts without the use of CuCl are disclosed. This eliminates the need for CuCl by replacing it with organic acids, mineral acids, mild oxidants or even water, resulting in high yields of Hoveyda-type metathesis catalysts. The invention provides an efficient method for preparing chelating-carbene metathesis catalysts by reacting a suitable ruthenium complex in high concentrations of the ligand precursors followed by crystallization from an organic solvent.

The invention relates to novel carbene ligands and their incorporated monomeric and resin/polymer linked ruthenium catalysts, which are recyclable and highly active for olefin metathesis reactions. It is disclosed that significant electronic effect of different substituted 2-alkoxybenzylidene ligands on the catalytic activity and stability of corresponding carbene ruthenium complexes, some of novel ruthenium complexes in the invention can be broadly used as catalysts highly efficient for olefin metathesis reactions, particularly in ring-closing (RCM), ring-opening (ROM), ring-opening metathesis polymerization (ROMP) and cross metathesis (CM) in high yield. The invention also relates to preparation of new ruthenium complexes and the use in metathesis.

The present invention provides compositions comprising metal complexes, and related methods. In some embodiments, metal complexes of the invention may be useful as catalysts for chemical reactions, including metathesis reactions, wherein the catalysts exhibit enhanced activity and stereoselectivity. In some embodiments, the invention may advantageously provide metal complexes comprising a stereogenic metal atom. Such metal complexes may be useful in enantioselective catalysis.

Improved catalysts useful in a number of organic synthesis reactions such as olefin metathesis and atom or group transfer reactions are made by bringing into contact a multi-coordinated metal complex comprising a multidentate Schiff base ligand, and one or more other ligands, with an acid under conditions such that said acid is able to at least partly cleave a bond between the metal and the multidentate Schiff base ligand of said metal complex, optionally through intermediate protonation of said Schiff base ligand.

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.

Catalytic compositions useful for carrying out the metathesis of unsaturated fatty bodies, in particular unsaturated fatty bodies comprising oleic acid or oleic acid esters, contain a ruthenium-based catalyst which can be isolated and which has the formula (I) below:

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 generally to synthetic procedures that include the step of ring-opening metathesis of cyclic olefins and reaction with an acyclic diene co-reactant to produce regularly repeating A,B-alternating olefin polymers. The A,B-alternating polymers are produced by varying reaction conditions and/or reactant proportions and using only two types of olefin metathesis (ring-opening and cross) to provide regularly repeating ABAB . . . etc. polymers via ring-opening metathesis polymerization (ROMP). More particularly, the invention pertains to synthesis of A,B-alternating olefin polymers via olefin metathesis reactions using a Group 8 transition metal complex as the metathesis catalyst. Polymers provided herein have utility in a variety of fields, including not only polymer chemistry per se, but also in the pharmaceutical, biomedical, and packaging industries where the structure and properties of polymers need to be tightly controlled.

A method is provided for synthesizing a polymer in a controlled fashion using a ring-opening metathesis polymerization (ROMP) reaction, wherein polymerization is carried out using a catalytically effective amount of an olefin metathesis catalyst and a bridged bicyclic or polycyclic olefin monomer that contains at least two heteroatoms directly or indirectly linked to each other. Preferred catalysts are Group 8 transition metal complexes, particularly complexes of Ru and Os. Such complexes include the ruthenium bisphosphine complex (PCy₃)₂(Cl)₂Ru═CHPh (1) and the ruthenium carbene complex (IMesH₂)(PCy₃)(Cl)₂Ru═CHPh (2). The invention also provides novel regioregular polymers synthesized using the aforementioned methodology, wherein the polymers may be saturated, unsaturated, protected, and/or telechelic. An exemplary polymer is poly((vinyl alcohol)₂-alt-methylene)(MVOH).

Acid washing of silica supports, used for supported tungsten catalysts, improves the activity of the resulting catalyst (i.e., its conversion level at a given temperature) for the metathesis of olefins, without compromising its selectivity to the desired conversion product(s). Exemplary catalysts and processes include those for the production of valuable light olefins such as propylene from a hydrocarbon feedstock comprising ethylene and butylene.

Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbene ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.

A process for the production of propylene from the metathesis of ethylene and 2-butene is disclosed wherein a mixed C₄ stream is first treated to enrich and separate the 2-butene from 1-butene and isobutene by isomerization of 1-butene and concurrent fractional distillation of the 2-butene and isobutene to provide the 2-butene feed the metathesis with ethylene. In addition the mixed C₄ stream may be treated to remove mercaptans and dienes prior to 2-butene enrichment.

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.

A process for separating a homogeneous metathesis catalyst and, optionally, one or more homogeneous metathesis catalyst degradation products from a metathesis reaction mixture containing in addition to said metathesis catalyst and said metathesis catalyst degradation product(s), one or more olefin metathesis products, one or more unconverted reactant olefins, and optionally, a solvent. The process involves contacting the metathesis reaction mixture with a nanofiltration membrane, such as a polyimide nanofiltration membrane, so as to recover a permeate containing a substantial portion of the olefin reaction products, the unconverted reactant olefins, and optional solvent, and a retentate containing the metathesis catalyst, and optionally, metathesis catalyst degradation product(s). In another aspect, this invention pertains to a continuous metathesis reaction-catalyst separation process, preferably, conducted in a nanofiltration membrane reactor.