Showing papers on "Norbornene published in 1968"

Process for preparing improved plastic compositions and the resulting products

Abstract: Plastics having improved impact resistance are prepared by interpolymerizing a mixture including a rubbery interpolymer of ethylene, at least one alpha monoolefin having 3-16 carbon atoms and an alkylidene norbornene, preferably 5-ethylidene-2norbornene and an alkenyl aromatic monomer such as styrene, a vinyl or vinylidene halide such as vinyl chloride, an acrylic monomer such as acrylonitrile, and mixtures thereof in an organic solvent for the rubbery polymer and in the presence of a free radical catalyst.

Ring-opening Polymerization of Norbornene and Its Derivatives by MoCl5, WCl6 and ReCl5 Catalysts

Abstract: Norbornene and such of its derivatives as exo-5,6-trimethylene norbornene (exo-TMN) and endo-dicyclopentadiene (endo-DCPT) have been polymerized via ring cleavage to high-molecularweight polymers, soluble in aromatics, by the use of MoCl5, WCl6, and ReCl5 catalysts in a carbon tetrachloride solvent. The ring-opening polymers obtained by MoCl5 have a trans-structure almost exclusively, on the other hand the polymers obtained by ReCl5 are rich in cis structures and those obtained by WCl6 are mixtures of the two. The reactivities of the monomers on those catalysts have been found to have the order of decreasing reactivity: exo-TMN>NE>endo-DCPD. In the ring-opening polymerization of norbornene by MoCl5, carbon disulfide and carbon tetrachloride have been found to be effective solvents. The yield increases with the rise in temperature and also upon the addition of a catalytic amount of tertiary amines in the midst of the polymerization procedure, while the structures of the polymers obtained do not change. The...

2-acetal-7-ketal-5-norbornene and 2-acetal-7-ketalnorbornane compounds

Abstract: 2-Acetal-7-ketal-5-norbornene compounds, such as 2-(1,3dioxolan-2-yl)-3-methyl-7,7-dimethoxy-5-norbornene, and the corresponding norbornane compounds, for example, 2-(1,3-dioxolan2-yl)-3-methyl-7,7-dimethoxynorbornane, are central nervous system depressants; and in addition, the norbornene compounds exhibit anticonvulsant activity. These compounds are synthesized from 1,2,3,4-tetrachloro-5-ketalcyclopentadienes and Alpha ,Bunsaturated aldehydes in a plural step synthesis comprising (1) a Diels-Alder addition, (2) acetalization, (3) dechlorination and, in the case of the norbornane compounds, (4) hydrogenation, as is illustrated by the following equations:

Poly(norbornene): Tensile and dynamic-mechanical properties

Abstract: The tensile and dynamic mechanical properties of poly(norbornene), prepared through ring-opening polymerization, were studied. Tensile strength and extensibility increased, while Young's modulus decreased with increasing molecular weight and with increasing content of trans relative to cis unsaturation. The damping factor Delta; was dependent on molecular weight only for the lower molecular weight samples. The out-of-phase modulus E″ and the damping factor decreased as the trans/cis ratio increased.

Addition of C-phenyl-N-methyl nitrone to norbornene and norbornadiene

Abstract: The reaction of C-phenyl-N-methyl nitrone with norbornene gave two 1:1 cycloadducts in a ratio of 9:1. Both adducts have been shown to possess an exo-cis isoxazolidine ring by nuclear magnetic resonance and to be diastereomeric at the benzylic carbon of the isoxazolidine ring by chemical degradation of both adducts to 3-exo-benzyl-2-exo-hydroxybicyclo [2•2•1] heptane. The reaction of the same nitrone with norbornadiene gave a 1:1 and a 2:1 adduct. The stereochemistry of the 1:1 adduct was shown to be the same as that of the major norbornene adduct which it gave on hydrogenation of the double bond. The structure of the 2:1 adduct was not investigated.

Carbanions. Part III. Pyramidal structure of α-sulphonyl carbanions in the norbornene system. Comparison with α-methoxycarbonyl carbanions

Abstract: The rates of the base-catalysed H–D exchange in endo- and exo-2-methoxycarbonylnorbornene and in endo- and exo-2-phenylsulphonylnorbornene have been measured. In the first two compounds the exchanges occur α to the methoxycarbonyl group; in the second two compounds α to the phenylsulphonyl group. The rates are slightly lower in the esters than in the sulphones, in accordance with the pKa values of simple carboxylic esters and alkyl sulphones. In the disubstituted norbornenes, methyl cis-endo- and cis-exo-3-phenylsulphonyl-bicyclo[2,2,1]hept-5-ene-2-carboxylates, there is isotopic exchange only at the position α to the methoxycarbonyl group, and inversion of the latter, endo→exo and exo→endo respectively; the exchange and inversion rates are identical. The trans-isomers remain unchanged in the reaction conditions of the cis-isomers. The results have been compared with those obtained in the case of the corresponding disubstituted norbornene acids. They are consistent with a pyramidal structure (sp3-hybridisation), and not with a planar structure (sp2-p-hybridisation) of α-sulphonyl carbanions in the norbornene system.

Synthesis of norbornene derivatives

Abstract: Cyclopentadiene present in a mixture with isoprene and/or piperylene is removed by selective reaction with an allyl compound (see Division C2)ALSO:The title compounds are prepared by reacting allyl compounds with cyclopentadiene which is in admixture with isoprene and/or piperylene