Showing papers on "Norbornene published in 1970"

Additions to bicyclic olefins. III. Stereochemistry of the epoxidation of norbornene, 7,7-dimethylnorbornene, and related bicyclic olefins. Steric effects in the 7,7-dimethylnorbornyl system

Abstract: A systematic study of addition reactions of norbornene, 7,7-dimethylnorbornene, and related bicyclic olefins has been undertaken in order to define more precisely the role of steric effects in controlling the stereo- chemistry of the additions and the nature of the intermediates in such addition reactions. The addition of borane to norbornene proceeds almost exclusively exo (99.573, whereas the corresponding addition to 7,7-dimethylnor- bornene proceeds preferentially endu (78%). Similarly, hydroboration of 2methylenenorbornane gives pref- erentially exo (85%), whereas 2-methylene-7,7-dimethylnorbornane gives preferentially (85%) endo product. Similar results were realized with 1-methylnorbornene, 2-methylnorbornene, bornene, and 2,7,7-trimethylnorbor- nene. Consequently, hydroboration of norbornene, 1- and 2-methylnorbornene, and 2-methylenenorbornane goes predominantly exo, evidently reflecting the greater steric availability of the exu position in this bicyclic system. However, the presence of 7,7-dimethyl substituents causes the addition to proceed preferentially from the endu direction. Consequently, in hydroboration the 7,7-dimethyl substituents alter the normal direction of addition to olefins of the norbornane structure, irrespective of whether the double bond is endocyclic, directly under the 7,7- substituents, or exocyclic, located to the side of the substituents. major argument for the u-bridged norbornyl cation A is the almost exclusive exo substitution realized in the solvolysis of 7,7-dimethylnorbornyl derivatives. 334

Photoelectron Spectra of Bicyclic and Exocyclic Olefins

Abstract: The construction and operational characteristics of a newly built photoelectron spectrometer are described. The photoelectron spectra of some bicyclic and exocyclic olefins and related saturated hydrocarbons have been recorded and their ionization potentials reported. The lowest ionization potentials are examined and discussed in terms of substitutional and ring strain effects. Ionization potential changes accompanying substitution in these molecules are explained by using empirically generalized substitution rules for saturated and unsaturated hydrocarbons. There appear to be no significant ring strain effects upon the lowest ionization potentials of four‐, five‐, or six‐membered ring exocyclic olefins or for the bicyclic molecules norbornane, norbornene, and norbornadiene. From a comparison of the ionization potential changes between 1, 3‐ and 1,4‐dienes, it is estimated that the two double bonds in norbornadiene are directionally coupled across the ring by an interaction energy of about 0.3 eV. From an...

The cationic polymerization of “endo” -dicyclopentadiene, 1,2–dihydro-“endo” -dicyclopentadiene and 9,10–dihydro-“endo” -dicyclopentadiene

Abstract: The polymerizations of “endo” -dicyclopentadience (I), 1,2–dihydro-“endo”-dicyclopentadiene (II) and 9,10–dihydro-“endo”-dicyclopentadiene (III), initiated by cationic systems, have been investigated under different conditions. Linear polymers with Mn in the range 1300–4500 have been obtained with (I) and (II): poly-(I) shows less than one double bond for structural unit. In the case of (III) only oligomers were observed. Copolymerization runs show a reactivity of (III) lower than (II). Spectroscopic and chemical analyses of the polymers obtained indicate that besides the norbornene double bond, also the cyclopentenic unsaturation, present in (I) and (III), reacts. Some evidences for a hydride shift in cyclopentence ring, after the attack of the initiator, were collected. In the case of poly-(I) the main enchainment resulted from the norbornene double bond opening, but about 30% of nortricyclene repeating unit was also observed.

Vulcanizable ethylene/propylene copolymers and process for their preparation

Abstract: There are disclosed new vulcanizable copolymers of ethylene and propylene containing unsaturations resulting from the presence therein of units deriving from the mixture obtained by the catalytic isomerization of vinylnorbornene said copolymers containing ethylene, propylene, ethylidene norbornene and at least one other diene selected from the group consisting of vinyl norbornene and vinyl norbornene and dicyclopentadiene. The copolymers have vulcanization rates comparable to those of ethylene/propylene/ethylidenenorbornene copolymers and yield elastomers having characteristics comparable to those of the vulcanized ethylene/propylene/ethylidenenorbornene copolymers, but are substantially more economical. The new modified ethylene/propylene copolymers are obtained by copolymerizing a mixture of the starting monomers in contact with catalysts prepared from hydrocarbon-soluble vanadium compounds and hydrides or organometallic compounds of beryllium, aluminum, or lithium-aluminum compounds.

Epdm rubber insulating composition

Abstract: AN INSULATING COMPOSITION FOR THE INSIDE OF ROCKET MOTORS COMPRISING (1) A RUBBER COMPRISING ETHYLENE, PROPYLENE AND A DIENE SELECTED FROM THE GROUP CONSISTING OF METHYLYLIDENE NORBORNENE AND ETHYLIDENE NORBORNENE, (2) CARBON OR SILICA (3) ASBESTOS (4) ZINC OXIDE AND (5) BROMOMETHYL ALKYLATED PHENOLFORMALDEHYDE RESIN.

Intramolecular addition of benzyl-lithium derivatives to norbornene rings

Abstract: Although α-aryl substituents stabilize organo-lithium reagents in tetrahydrofuran, such derivatives can attack a norbornene double-bond intramolecularly to produce a more reactive, tricyclic s-alkyl-lithium that appears to abstract a proton preferentially from the solvent.

Some Semi-Empirical SCF MO Calculations on Norbornadiene, Norbornene, and Their 7-Cations

Abstract: Using a semi-empirical SCF MO method for valence electron systems proposed previously by the present authors, the electronic structures of norbornadiene (NBD), norbornene (NBE), and their 7-cations are discussed, together with the configurational problem of the 7-cations. In NBE and NBD, the interaction between the π AO’s in the double bond and the AO’s of the other parts of the molecules is made clear by the charge densities and the bond orders. For the first electronic transition assigned to a π–σ* or σ–π* in NBD, the present calcuation gives a rather larger excitation energy than does the experiment. For 7-norbornenyl and 7-norbornadienyl cations, the presence of structures distorted from NBE and NBD respectively can theoretically be concluded. The delocalization of the positive charge and the bonding interaction between the bridged carbon atom and the double bond carbon atoms support the concept of the so-called non-classical carbonium ions.

Ethylene-olefin-alkenyl norbornene elastomers

Abstract: There is disclosed a new class of substantially linear, amorphous, unsaturated, vulcanizable, high molecular weight copolymers of ethylene, a higher alpha-olefin of the formula CH 2 = CHR in which R is an alkyl group containing from 1 to 6 carbon atoms and certain specific omega-alkenyl derivatives of norbornene in which the double bond of the alkenyl group is non-vinyl and occurs at either end of said group. A process for the preparation of the new copolymers by the use of catalysts acting according to an anionic coordinate mechanism is also disclosed.

The determination of unsaturation in ethylene propylene terpolymers and butyl rubber with pyridinium bromide perbromide

Abstract: The reagent pyridinium bromide perbromide (PBPB) has been investigated for the determination of unsaturation in model olefins and in polymers of low total unsaturation. Model olefins give 92%–100% reaction for a 1-hr reaction period. Ethylene propylene terpolymers react quantitatively without substitution or elimination and without second addition reactions when the termonomer unit is 1,4 hexadiene, methylene norbornene, ethylidene norbornene, or cyclooctadiene. Dicyclopentadiene terpolymers react incompletely. These reactions take place in carbon tetrachloride/10% methanol solution, the reagent being added as a methanolic solution. Iodine chloride can also be used under specified conditions for the more reactive termonomer units in this solvent mixture. Under the same conditions the PBPB reagent reacts stoichiometrically with butyl rubber, without second addition or substitution reactions. The unsaturation results also agree with those obtained using bromine or iodine monochloride in carbon tetrachloride solution, but both of these reagents give slight substitution reactions.

Direkte Photolyse von Kohlenoxidsulfid in Alkoholen und Acetonitril in Gegenwart von Olefinen. Reaktionen von Triplett‐Schwefelatomen mit Norbornen in Äthanol und 1.4‐Dioxan

Abstract: Die COS-Photolyse fuhrt in Methanol wie auch in Acetonitril in Gegenwart von Cyclohexen bzw. Octen-(1) zur Bildung der Episulfide durch Reaktion von S(3P)-Atomen mit den Olefinen. Mit Norbornen dagegen wird keine Episulfidbildung beobachtet; die COS-Photolyse in athanol liefert ausschlieslich die beiden diastereomeren Dinorbornylsulfide 1a und 1 b, wahrend in 1.4-Dioxan auserdem noch [Norbornyl-(2)]-[1.4-dioxanyl]-sulfid (5) entsteht. Die Bildungsweisen dieser Verbindungen werden diskutiert. Direct Photolysis of Carbonyl Sulfide in Alcohols and Acetonitrile in the Presence of Olefins. Reactions of Triplet Sulfur Atoms with Norbornene in Ethanol and 1, 4-Dioxane Photolysis of COS in methanol as well as in acetonitrile in the presence of cyclohexene or 1-octene gives rise to the formation of the corresponding episulfides due to the addition of triplet sulfur atoms, S(3P). With norbornene, however, episulfide formation ist not observed; only diastereomeric dinorbornyl sulfides 1a and 1b are obtained if the reaction is carried out in ethanol, whereas norbornyl 1,4-dioxanyl sulfide (5) is produced in addition to 1 a and 1 b, if 1,4-dioxane is used as solvent. The mode of formation of these compounds is discussed.

Process for isomerizing 5-alkenylnorbornene

Abstract: 5-ALKENYLNORBORNENE IS ISOMERIZED TO 5-ALKYLIDENE NORBORNENE BY ALLOWING THE 5-ALKENYLNORBORNENE TO COME IN CONTACT WITH A BASIC CATALYST CONSISTING OF AN ALKALI METAL HYDRIDE AND A DIMETHYLSULFOXIDE OR AN ALIPHATIC AMINE. THE 5-ALKENYLNORBORNENE IS UTILIZED AS THE THIRD COMPONENT FOR ETHYLENEPROPYLENE RUBBER.

The chemistry of azidotropones. Part III. Formation and decomposition of Δ2-triazolines derived from norbornene

Abstract: 1,3-Cycloadditions of 2-, 3-, and 4-azidotropone to norbornene have been studied. The products formed on thermolysis of the 1-substituted 1,2,3-Δ2-triazolines so obtained have been characterised as derivatives of syn-7-aminonorbornene and 3-azatricyclo[3,2,1,02,4]octane. Notable differences in the rates of formation and stabilities of the triazolines, and in the relative proportions of the two types of thermolysis product, are observed between the compounds derived from 2-azidotropone on the one hand, and those from the 3- and 4-isomers on the other.

Process for the manufacture of amorphous copolymers from ethylene and higher alpha-olefins in suspension

Abstract: 1,161,731. Copolymerizing olefins. FARBWERKE HOECHST A.G. 11 March, 1968 [10 March, 1967], No. 11760/68. Heading C3P. Copolymers of ethylene, an alpha-olefin of the formula R-CH=CH 2 , where R is an aliphatic branch or straight-chain hydrocarbon radical containing less than seven carbon atoms, and optionally a hydrocarbon with two non- conjugated double bonds in an amount such that the polymer obtained has an iodine number of at most 50, are made by copolymerizing the monomers in the presence of (1) as dispersion medium an aliphatic halohydrocarbon which does not dissolve the copolymer under the reaction conditions, (2) a catalyst comprising a vanadium compound and an organoaluminium compound both soluble in the dispersion medium and (3) 0.0001% to 10% by weight, calculated on the dispersion medium, of a finely divided inert solid organic polymer of particle size 0-005 to 300 microns which does not inhibit the catalyst activity, and is insoluble in the dispersion medium and in the precipitating polymer. The copolymerization is carried out at a pressure of 1 to 30 atmospheres, a temperature in the range of - 30‹ C. and +50‹ C., with stirring or mechanical agitation. Specified organic polymers are polyethylene, polypropylene, polybutene-1, poly-3-methylbutene-1, polypentene-1, poly - 4 - methylpentene - 1, polymers of C10 to C24 olefins, copolymers of the above olefins, polyacrylonitrile, polyvinyl chloride, polyethylene glycol terephthalate, polycaprolactam, polyvinyl fluoride, polytetrafluoroethylene, polyvinylidene fluoride, condensation products of formaldehyde with phenols or amines, and pulverized coconut shells. Suitable dispersing media are 1,2-dichloropropane, 1,2,2 - trichloro - 1,1,2 - trifluoroethane, ethylene chloride, 1,2 - dichloroethane and methylene chloride. The optional third component may be 1,4-cis-hexadiene, 1,4-transhexadiene, alkenyl-norbornenes, alkylidene-norbornenes, and dicyclopentadiene. In the examples are copolymerized ethylene and propylene, ethylene, propylene and methylbutenyl norbornene, and ethylene, propylene and 1,4- cis-hexadiene.

Films and Fibres of Acrylonitrile Copolymers

Abstract: 1,186,362. Acrylonitrile terpolymer films. IMPERIAL CHEMICAL INDUSTRIES Ltd. 5 March, 1968 [10 March, 1967; 20 Sept., 1967], Nos. 42895/67 and 42900/67. Heading B5B. [Also in Division C3] A film or fibre is made from a random copolymer of 50% to 90% molar of acrylonitrile and 50% to 10% molar of at least one aromatic olefin, the sum of these percentages being 100%, into which is incorporated as copolymerized units at least one monomer selected from maleimide and its N-substituted derivatives and norbornene and its derivatives including methylene norbornane in a molar amount less than that of the aromatic olefin. In the examples, films prepared by solvent casting a terpolymer of acrylonitrile, N-ochlorophenylmaleimide and styrene, or alphamethylstyrene, are uniaxially or biaxially oriented. The uniaxially oriented films may be fibrillated.

Copolymers of acrylonitrile

Abstract: 1,185,308. Acrylonitrile terpolymers. IMPERIAL CHEMICAL INDUSTRIES Ltd. 29 Feb., 1968 [7 March, 1967; 20 Sept., 1967], Nos. 42897/67 and 42898/67. Divided out of 1,185,305. Headings C3G and C3P. A random copolymer comprises units of acrylonitrile and units of at least one aromatic olefin in a molar ratio of acrylonitrile to aromatic olefin of between 2 and 6 and contains up to 10 mole per cent (where the sum of acrylonitrile and aromatic olefin units represents 100 mole per cent) of copolymerized units of at least one monomer selected from maleimide and its N- substituted derivatives and norbornene and its derivatives, including methylene norbornane. The aromatic olefin is, e.g. styrene or a substituted styrene, acenaphthylene, indene, coumarone, 1-vinyl naphthalene, 2-vinyl thiophene, 3-vinyl phenanthrene, 2-methyl-5-vinyl pyridine or N-vinyl carbazole. Preferred maleimides are N-aryl maleimides, e.g. N-phenyl or N-o-chlorophenyl maleimide. The copolymer is used in blends with graft copolymers such as polybutadiene grafted with acrylonitrile and isobutene or styrene. The copolymer is prepared by a process in which at least the aromatic olefin is fed into the reaction medium as the polymerization proceeds, at a rate determined by the heat evolved by the polymerization. In the examples, terpolymers of acrylonitrile and styrene with N-o-chlorophenyl maleimide, 5- cyanonorbomene, maleimide or methylene norbornane are prepared, as are terpolymers of acrylonitrile and alpha-methyl styrene with N- o-chlorophenyl maleimide or maleimide, by polymerization in an aqueous medium. The acrylonitrile / styrene / N-o-chlorophenyl maleimide terpolymer is blended with a stabilized polybutadiene/acrylonitrile-isobutene graft copolymer, or polybutadiene / acrylonitrilestyrene graft copolymer and the acrylonitrile/ alpha-methyl styrene/N-o-chlorophenyl maleimide terpolymer is similarly blended.

Unsaturated ring compounds: Communication 31. Determination of configuration of substituent in position 7 of norbornene skeleton

Abstract: 1. The hydrogenation kinetics of endo anhydrides of 7-syn-methyl-(II) and 7-anti-methyl-(III)-bicyclo [2,2,1]-hept-2-ene-5,6-dicarboxylic acids and the corresponding unsubstituted anhydride (I) have been in vestigated. Hydrogenation of the syn isomer (II) took place at approximately half the rate of the anti isomer (III) and the unsubstituted anhydride (I). The last two compounds gave approximately the same hydro genation rates. 2. A convenient method is proposed for determined the configuration of a substituent in position 7 of the bicyclo-[2,2,1]-heptene skeleton.