Showing papers on "Norbornene published in 1996"

Synthesis and Applications of RuCl2(CHR‘)(PR3)2: The Influence of the Alkylidene Moiety on Metathesis Activity

Abstract: The reactions of RuCl2(PPh3)3 with a number of diazoalkanes were surveyed, and alkylidene transfer to give RuCl2(CHR)(PPh3)2 (R = Me (1), Et (2)) and RuCl2(CH-p-C6H4X)(PPh3)2 (X = H (3), NMe2 (4), OMe (5), Me (6), F (7), Cl (8), NO2 (9)) was observed for alkyl diazoalkanes RCHN2 and various para-substituted aryl diazoalkanes p-C6H4XCHN2. Kinetic studies on the living ring-opening metathesis polymerization (ROMP) of norbornene using complexes 3−9 as catalysts have shown that initiation is in all cases faster than propagation (ki/kp = 9 for 3) and that the electronic effect of X on the metathesis activity of 3−9 is relatively small. Phosphine exchange in 3−9 with tricyclohexylphosphine leads to RuCl2(CH-p-C6H4X)(PCy3)2 10−16, which are efficient catalysts for ROMP of cyclooctene (PDI = 1.51−1.63) and 1,5-cyclooctadiene (PDI = 1.56−1.67). The crystal structure of RuCl2(CH-p-C6H4Cl)(PCy3)2 (15) indicated a distorted square-pyramidal geometry, in which the two phosphines are trans to each other, and the alkyli...

(η3-Allyl)palladium(II) and Palladium(II) Nitrile Catalysts for the Addition Polymerization of Norbornene Derivatives with Functional Groups

Abstract: Cycloaliphatic polyolefins with functional groups were obtained by Pd(II)-catalyzed homo- and copolymerizations of norbornene derivatives. Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, the corresponding methyl ester, 2-(hydroxymethyl)bicyclo[2.2.1]hept-5-ene, and the corresponding octanoate and decanoate were used as the monomers in these addition polymerizations. Pd(II)−nitrile catalysts [Pd(RCN)4][BF4]2 (with R = CH3 and C2H5) quite selectively polymerized the exo isomers of the esters of 2-(hydroxymethyl)bicyclo[2.2.1]hept-5-ene. Monomer mixtures containing an 80/20 ratio of endo/exo isomers were converted into polymers containing more than 50% of exo units. 1H NMR studies showed that the predominant fraction of the endo isomer remained unreacted. The nitrile based Pd catalysts were not sufficiently active to polymerize the monomers with electron-withdrawing substituents linked to the bicyclic unit at ambient temperature. In-situ prepared (η3-allyl)palladium complexes with associated tetrafluoroborate an...

Retro-Diels−Alder Femtosecond Reaction Dynamics

Abstract: In this communication, we present our first femtosecond (fs), real-time studies of the retro-Diels-Alder reactions of norbornene (NB) and norbornadiene (NBD), products of the cycloaddition of cyclopentadiene with ethylene and acetylene, respectively. The reaction path, together with transition state (TS) structures, is displayed in Figure 1 (bottom). The experiments were designed with the following considerations in mind. First, the reactions were studied in a molecular beam in order to isolate the elementary processes, free of solvent perturbations. Second, we examined the dynamics of the reaction from a well-defined initial geometry, a precursor of Diels-Alder products.

Synthesis of ABA triblock copolymers of norbornenes and 7-oxanorbornenes via living ring-opening metathesis polymerization using well-defined, bimetallic ruthenium catalysts

Abstract: Norbornene and 7-oxanorbornene derivatives were polymerized by ring-opening metathesis polymerization (ROMP) in a living manner by employing three new well-defined, bimetallic ruthenium catalysts (...

Romp polymerization in the presence of peroxide crosslinking agents to form high-density crosslinked polymers

Abstract: Methods of forming polycycloolefins having high crosslink density are disclosed. Olefins are polymerized via a metathesis mechanism in the presence of a crosslinking agent and a catalyst. The crosslinking agent generally comprises a peroxide that decomposes into reactive species forming crosslinks during post-cure. The catalyst is a ruthenium or osmium carbene complex of the formula: ##STR1## wherein M is Os or Ru; R and R 1 are independently selected from hydrogen or a hydrocarbon selected from the group consisting of C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 2 -C 20 alkoxycarbonyl, aryl, C 1 -C 20 carboxylate, C 1 -C 20 alkoxy, C 2 -C 20 alkenyloxy, C 2 -C 20 alkynyloxy and aryloxy; X and X 1 are independently selected from any anionic ligand; and L and L 1 are independently selected from any neutral electron donor. Preferably, L and L 1 are trialkylphosphine ligands and at least one of the alkyl groups on the phosphine ligand may be a secondary alkyl or cycloalkyl group, especially P(isopropyl) 3 , P(cyclopentyl) 3 and P(cyclohexyl) 3 . Preferred crosslinking agents are peroxides, such as t-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy) hexyne-3, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-(tert-butylperoxy) hexane or mixtures thereof. Olefins may be cyclic (e.g., monocyclic, bicyclic or tricyclic) or acyclic. Norbornene or norbornene derivatives are especially preferred.

(η3‐allyl)palladium(II) catalysts for the addition polymerization of norbornene derivatives with functional groups

Abstract: Cycloaliphatic polyolefins with functional groups were prepared by the Pd(II)-catalyzed addition polymerization of norbornene derivatives. Homo- and copolymers containing repeating units based on bicyclo[2.2.1] hept-5-en-2-ylmethyl decanoate (endo/exo-ratio = 80/20), bicyclo[2.2.1]hept-5-ene-2-carboxylic acid methyl ester (exo/endo = 80/20), bicyclo[2.2.1]hept-5-ene-2-methanol (endo/exo = 80/20), and bicyclo[2.2.1]hept-5-ene-2-carboxylic acid (100% endo) were prepared in 49–99% yields with {(η3-allyl)Pd(BF4)} and {(η3-allyl)Pd(SbF6)} as catalysts. The catalyst containing the hexafluoroantimonate ion was slightly more active than the tetrafluoroborate based Pd-complex.

Development of new cyclic olefin polymers for optical uses

Abstract: New cyclic olefin polymers (COP) with a better balance of properties than those of conventional optical plastics have been developed by using norbornene monomers. The COP are prepared by ring-opening metathesis polymerization of norbornene monomers followed by complete hydrogenation of double bonds. The COP have practically been applied for optical uses such as lenses, prisms and optical discs.

Titania-silica aerogels with superior catalytic performance in olefin epoxidation compared to large pore Ti-molecular sieves

Abstract: The paper provides a short overview on the various Ti- and Si-containing epoxidation catalysts, with a focus on the development and characterisation of titania-silica mixed oxides prepared by the sol-gel-aerogel method. Titania-silica aerogels, dried by semicontinuous extraction of the solvent with supercritical CO2 at low temperature, possess high surface area, an amorphous mesoporous structure, and a rather even distribution of Ti in the silica matrix. The catalytic activities of mixed oxides, silica-supported titania and Ti-substituted molecular sieves (TS-1, Ti-Β and Ti-MCM-41) are compared in the epoxidation of 1-hexene, 1-octene, cyclohexene, cyclododecene and norbornene, based on literature data. The activities (i.e. the amount of converted olefin per unit time and catalyst weight) vary in a broad range of several orders of magnitude. It is shown that the low temperature aerogel containing 20 wt% TiO2 is superior to any other Ti- and Si-containing catalyst for the epoxidation of cyclic olefins. In the epoxidation of linear alkenes TS-1 has outstanding activity. Ti-substituted large and ultra-large pore molecular sieves require further development concerning their catalytic performance.

Synthesis of α-norbornenyl polystyrene macromonomers and their ring-opening metathesis polymerization

Abstract: Polystyrene macromonomers, fitted with a norbornenyl unsaturation in α position, have been obtained from a norbornene based carbanionic initiator that has been purposely designed to this end. The advantages of this synthetic scheme over that based on the deactivation of living PS chains are emphasized. One of the macromonomers prepared has been subsequently polymerized by ring-opening metathesis, using a Schrock complex as initiator. The characterization of the resulting polymacromonomers showed that the metathesis process occurred under “living” conditions.

Determination of the tacticity of ring‐opened metathesis polymers of norbornene and norbornadiene by 13C NMR spectroscopy of their hydrogenated derivatives

Abstract: The 125 MHz 13 C nuclear magnetic resonance (NMR) spectra of the hydrogenated derivatives of ring-opened metathesis polymers (ROMP) of bicydo[2.2.1]hept-2-ene (norbornene) and bicydo[2.2.1]hepta-2,5-diene (norbornadiene) prepared using a range of initiators, have been analysed in detail. The signals due to the methylene carbon atoms in the enchained cyclopentyl rings of these polymers show fine structure which is assigned to m and r ring dyads and mm, mr/rm and rr ring triads, enabling the tacticity of the hydrogenated polymer, and thus of the polyolefin precursor, to be determined for high-cis or high-trans polymers. Novel methods for making high-cis polymers are described and solvent-dependent variations in the stereospecificity of the propagation reaction have been observed.

Ring-Opening Metathesis Polymerizations in Carbon Dioxide

Abstract: The polymerization of norbornene was successfully initiated with Ru(H2O)6(tos)2 in a carbon dioxide medium. The resultant poly(norbornene) was prepared with yields and molecular weights comparable to those obtained in other solvent systems. It was also found that the cis/trans ratio of the polymer microstructure could be controlled by the addition of various amounts of methanol to the reaction mixture. A detailed account of the polymerizations is described and believed to be the first example of a ring-opening metathesis polymerization in carbon dioxide.

Mixed ligand complexes of chromium(III) and iron(III): synthesis and evaluation as catalysts for oxidation of olefins

Abstract: The mixed ligand complexes Cr III (dpa)(L)Cl and Fe III (dpa)(L)(H 2 O) n Cl (where dpa = dipicolinic acid, l = ethylenediamine, 2,2-bipyridine or 1,10-phenanthroline, n = 1 or 2) were synthesized and characterized by elemental analysis and spectral, magnetic, conductance and electrochemical studies. The complexes were evaluated for their activity as catalysts for the epoxidation of olefins. The chromium complexes catalyzed epoxidation of olefins, viz., norbornene, cis -cyclooctene, styrene and cyclohexene with iodosylbenzene, to give corresponding epoxides. Oxidation of cyclohexene gave allylic oxidation products besides the epoxide. The iron complexes were nearly inactive as epoxidation catalysts under these conditions. Spectrophotometric and electrochemical measurements were used to deduce the cause of low catalytic activity.

Effects of cis-trans-configurations of the main chains of poly(trimethylsilyl norbornene) on its transport and sorption properties as well as free volume

Abstract: Samples of poly(trimetylsilyl norbornene) having different content of cis configurations of double bonds in the main chains were prepared by ring opening metathesis polymerization in the presence of the catalysts characterized by different stereoselectivity (Re2O7, RuCI3, WCI6). It was shown that the polymer obtained in the presence of the WCI6 catalysts having the closest content of the cis-and trans-configurations is distinguished by the largest gas permeability, diffusion, and solubility coefficients. Determination of the parameters of gas sorption isotherms and estimation of free volume using group contribution and positron annihilation methods allowed to conclude that microstructure of this polymer (cis/trans ratio) affects its free volume and, therfore, its transport and thermodynamic properties. © 1996 John Wiley & Sons, Inc.

Light-diffusing plate

Abstract: PURPOSE: To obtain a light-diffusing plate comprising a specific cyclic olefin resin and an organic or inorganic filler, enabling to widely control optical transmittance, excellent in heat resistance, dimensional stability and chemical resistance, and free from chromatic aberration and changes in optical characteristics due to the absorption of water. CONSTITUTION: The light-diffusing plate comprises (A) a cyclic olefin resin selected from (i) an ethylene-cyclic olefin random copolymer produced from the copolymerization of ethylene with a cyclic olefin of formula I, (n, q are 0, 1; m is 0, a positive integer; R to R , R , R are H, hydrocarbon, etc.,) or formula II (p, q are 0, 1, or larger integer; m, n are 0-2; R to R are H, alkoxy, etc.,) (e.g. norbornene), (ii) the ring-opening (co)polymer of the cyclic olefin of formula I or II, (iii) the hydrogenation product of the component ii, and (iv) the graft-modified product of the components i-iii, and (B) an organic filler (preferably a polymer having a difference of >=0.005 between the refractive index of the polymer and that of the component A, or the cross-linked particles of the polymer) or an inorganic filler (preferably the filler having an average particle diameter of 0.5-50μm).

Enantioselective rearrangement of exo-norbornene oxide to nortricyclanol

Abstract: The enantioselective α-deprotonation-rearrangement of exo -norbornene oxide 1 to (−)-nortricyclanol 2 in up to 52% ee using a nonracemic lithium amide, or an organolithium in the presence of (−)-sparteine, is described.

Elastomeric vehicle brake parts and power transmission belts

Abstract: Motor vehicle brake parts and power transmission belt based on an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer are manufactured with more efficiency due to brake part compounds having lower viscosity, faster and fuller cures than ethylene, alpha-olefins, diene monomer compounds, where the diene monomer is other than vinyl norbornene. Additionally, the brake parts and the power transmission belt based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer have improved resistance to elevated temperature properties, and good heat aging characteristics, compared to for instance ethylene, alpha-olefin, non-conjugated diene elastomers (where the diene is other than vinyl norbornene) polychloroprene, or styrene butadiene rubbers.

Asymmetric hydroesterification of norbornene by chiral non-chelate biphosphine palladium complexes

Abstract: Asymmetric induction up to 92.2% has been obtained in the hydroesterification of norbornene with carbon monoxide and alcohols in the presence of Pd(OAc)2, 1,4:3,6-dianhydro-2,5-dideoxy-2,5-bis(diphenylphosphino)-L-iditol and p-toluenesulfonic acid.

Thermoplastic norbornene-based resin composition

Abstract: PROBLEM TO BE SOLVED: To obtain excellent electrical characteristics by using as the constituents a thermoplastic norbornene based resin and a thermoplastic elastomer having a specified iodine value and weight-average molecular weight. SOLUTION: A thermoplastic norbornene based resin having an intrinsic viscosity (in decalin, at 80°C) of 0.01-20dl/g and a molecular weight distribution of at most 4.0, in an amount of 100 pts.wt. is blended with 5-100 pts.wt. thermoplastic elastomer comprising, e.g. a hydrogenated styrene/isoprene block copolymer having a weight-average molecular weight of 100,000 to 1,000,000 and an iodine value of 50g/100g and arbitrary ingredients comprising, e.g. other thermoplastic resin such as PE in an appropriate amount, a lubricant such as MgCO 3 in an amount of 0.001-5 pts.wt., a phenol-base antioxidant in an amount of 0.001-5 pts.wt., a hindered amine base ultraviolet absorber, etc., in an amount of 0.001-5 pts.wt., a hydrochloric acid absorber such as sodium stearate in an amount of 0.001-5 pts.wt., and an antistatic agent in an amount of 0-5 pts.wt. This blend is melted, kneaded and extruded through, e.g. a twin-screw extruder to give a thermoplastic norbornene based resin composition. COPYRIGHT: (C)1998,JPO

Electrical devices including ethylene, alpha-olefin, vinyl norbornene elastomeric polymers

Abstract: Elastomeric polymers including ethylene, alpha-olefin and vinyl norbornene are shown to have improved extrusion characteristics, improved electrical properties, improved cure characteristics compared to ethylene, alpha-olefin, non-conjugated diene elastomeric polymers containing non-conjugated dienes other than vinyl norbornene. The elastomeric polymers containing vinyl norbornene generally have a branching index below 0.5.

Elastomeric vehicle vibration damping devices

Abstract: Motor vehicle vibration damping parts based on an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer are manufactured with more efficiency due to vibration damping part compounds having lower viscosity, easier processing than ethylene, alpha-olefins, diene monomer compounds, where the diene monomer is other than vinyl norbornene. Additionally, the engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer have better heat aging characteristics than natural rubber, when temperature of service exceed 120° C., maintain more constant dynamic characteristics of the mount when running at elevated temperature like 120° C. Finally the engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer can be manufactured with compound containing less peroxide as curing agent, than ethylene, alpha-olefins, diene monomer compounds, where the diene monomer is other than vinyl norbornene. Those engine mounts or other vibration damping parts based on the ethylene, alpha-olefin, vinyl norbornene elastomeric polymer provide better aging properties so the service life of the parts are greatly extended vs. natural rubber part.

Norbornene-based addition type copolymer, epoxy group-containing norbornene-based addition type copolymer and crosslinkable polymer composition

Abstract: PROBLEM TO BE SOLVED: To obtain the subject copolymer, having a specific recurring unit and capable of producing a copolymer excellent in electrical characteristics such as permittivity and dielectric loss tangent and heat resistance and exhibiting excellent adhesion to a metal layer by reacting the subject copolymer with a peroxide as an epoxidizing agent. SOLUTION: The objective copolymer comprises at least one kind of norbornene-based addition type recurring unit selected from a group comprising a recurring unit of formula I [(a) to (c) are each 0, 1 or 2; R 1 to R 14 are independently H, a hydrocarbon, a halogen, an alkoxy, etc.] and a recurring unit of formula II [(d) to (g) and π are each 0 or 1 or 2; R 15 to R 30 are independently H, an alkyl, a hologen, an alkoxy, etc.), and a norbornene-based addition type recurring unit of formula III [(h) to (j) are each 0, 1 or 2; R 31 to R 44 are independently H, an alkyl, a halogen, an alkoxy, cyano, etc.) and the copolymer has 500-500,000 number-average molecular weight. The copolymer can thereby widely utilized as an insulating material, etc., in electrical and electronic equipment fields. COPYRIGHT: (C)1998,JPO

Norbornene-based polymer and its production

Abstract: PROBLEM TO BE SOLVED: To produce the subject polymer, excellent in transparency, moisture resistance, etc., by carrying out the ring opening copolymerization of a tetracyclododecene-based monomer with a dicyclopentadiene-based monomer and a norbornene-based monomer having an aromatic ring structure and then hydrogenating the resultant copolymer. SOLUTION: This polymer comprises a recurring unit of formula I [(a) to (c) are each 0, 1 or 2; R to R are each independently H, a hydrocarbon, a halogen, etc.; the dotted line on the solid line is a C-C single bond or a double bond], a recurring unit of formula II [(d) to (f) and (w) are each 0, 1 or 2; R to R are each independently H, a hydrocarbon, a halogen, etc.] and a recurring unit of formula III [(g), (h), (j) and (k) are each 0, 1 or 2; R to R are each independently H, a hydrocarbon, a halogen, etc.] and has 1,000-500,000 number-average molecular weight. The ratio of the recurring units having C-C bond in the main chain structure is <=20mol%. Thereby, the production and molding are facilitated due to excellent stability to solvents.

Copolymerization of Carbon Monoxide and Norbornene with a Palladium Catalyst

Abstract: Carbon monoxide and norbornene (NBE) with Pd(CH 3 COO) 2 under various conditions were copolymerized at 90°C. Elemental analysis, infrared spectra and NMR spectra showed that the copolymers contained ketone and ring structures. Bidentate nitrogen and phosphorus ligands were more effective ligands to stabilize catalytic activity than monodentate arsenic or phosphorus ligands. Methanol and the protonic acid served as coinitiator and chain-transfer agents. X-Ray diffraction analysis shows the copolymer to be partially crystalline. Thermogravimctric analysis showed that the copolymer started to lose mass at 350°C and that maximum decomposition occurred at 447 C. The NBE/CO copolymer obtained from various ligands has a glass transition temperature (T g ) in the range 100-126°C. Hydrogenation of norbornene/CO copolymer with a reducing agent yielded a hydroxy-containing polymer.

Norbornane cyclic carbonate composition

Abstract: PROBLEM TO BE SOLVED: To obtain the subject composition capable of forming a polymer having excellent adhesivity and thermal properties and low cure shrinkage by compounding a norbornane cyclic carbonate, a norbornene cyclic carbonate and an amine-based anionic ring-opening polymerization initiator. SOLUTION: This composition contains a norbornane cyclic carbonate of the formula I, a norbornene cyclic carbonate of the formula II and an amine- based anionic ring-opening polymerization initiator as essential components. The weight ratio of the cyclic carbonate of the formula I to the cyclic carbonate of the formula II (I/II) is preferably between 10/90 and 90/10. The polymerization initiator is preferably 1,8-diazabicyclo[5.4.0]undec-7-ene, triethylenediamine or 4-dimethylaminopyridine. The polymer is effectively usable as an industrial material such as casting material, sealing material and bonding material. COPYRIGHT: (C)1998,JPO

Norbornene-based addition type copolymer

Abstract: PURPOSE: To obtain a new thermoplastic norbornene-based copolymer, excellent in transparency, low birefringent properties, moisture, water and chemical resistances, electrical characteristics and low eluting properties of impurities and having a proper glass transition temperature and further heat resistance and easiness of melt molding in combination. CONSTITUTION: This addition type copolymer is obtained by carrying out the addition type copolymerization of (A) norbornene or a substituted norbornene having a =5C alkyl substituent group (preferably 5- hexyl-2-norbornene) without opening the ring. The resultant copolymer comprises (a) 15-70wt.% addition type recurring unit derived from the monomer (A) and (b) 85-30wt.% addition type recurring unit derived from the monomer (B) and has 50,000-1,000,000 number-average molecular weight and 140-210 deg.C glass transition temperature.

Catalytic properties of novel chiral polyoxomolybdate(VI) salts: The ring-opening metathesis polymerization (ROMP) of norbornene

Abstract: Each of the chiral polyoxomolybdate(VI) salts (R 3 NH) 4 [Mo 8 O 26 (R 3 N) 2 ] and (Na) 2 (R 3 NH) 2 [Mo 8 O 26 ] (R 3 N = (+)-cinchonine, (+)-hydroquinidine or (−)-quinine), in the presence of the cocatalyst EtAlCl 2 , catalyses the ring-opening metathesis polymerization of norbornene at room temperature. The polynorbornene produced in these reactions was found to be mostly insoluble. Inclusion of a chain transfer agent, 1-hexene, in the reactions leads to greatly improved yields of polynorbornene which is freely soluble in chloroform, and the quantity of polymer formed is highly sensitive to the amount of 1-hexene added.

Peroxide crosslinking of romp polymers

Abstract: Methods of forming polycycloolefins having high crosslink density are disclosed. Olefins are polymerized via a metathesis mechanism in the presence of a crosslinking agent and a catalyst. The crosslinking agent generally comprises a peroxide that decomposes into reactive species forming crosslinks during post-cure. The catalyst is a ruthenium or osmium carbene complex of general formula (I), wherein M is Os or Ru; R and R1 are independently selected from hydrogen or a hydrocarbon selected from the group consisting of C?1?-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C2-C20 alkoxycarbonyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy and aryloxy; X and X?1? are independently selected from any anionic ligand; and L and L1 are independently selected from any neutral electron donor. Preferably, L and L1 are trialkylphosphine ligands and at least one of the alkyl groups on the phosphine ligand may be a secondary alkyl or cycloalkyl group, especially P(isopropyl)?3?, P(cyclopentyl)3 and P(cyclohexyl)3. Preferred crosslinking agents are peroxides, such as t-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy) hexyne-3, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-(tert-butylperoxy) hexane or mixtures thereof. Olefins may be cyclic (e.g., monocyclic, bicyclic or tricyclic) or acyclic. Norbornene or norbornene derivatives are especially preferred.