1001846-18-9Relevant academic research and scientific papers
Quantitative α-alkylation of primary nitriles
Rojas, Giovanni,Baughman, Travis W.,Wagener, Kenneth B.
, p. 3923 - 3931 (2007)
A synthetic pathway that produces alkyl α,ω-cyanodiolefins in quantitative yield is described, applying chemistry that is based on simple α-alkylation of alkyl nitriles. Three amide bases, lithium 2,2,6,6-tetramethylpiperidide, lithium diisopropylamide, and sodium amide, are used to create the α-carbanions that undergo substitution with various alkylating agents. Optimization leads to essentially quantitative conversions for every substrate/example reported herein, which will prove useful in many synthetic schemes. Copyright Taylor & Francis Group, LLC.
Precision polyethylene: Changes in morphology as a function of alkyl branch size
Rojas, Giovanni,Inci, Bora,Wei, Yuying,Wagener, Kenneth B.
supporting information; scheme or table, p. 17376 - 17386 (2010/03/23)
Metathesis polycondensation chemistry has been employed to control the crystalline morphology of a series of 11 precision-branched polyethylene structures, the branch being placed on each 21st carbon and ranging in size from a methyl group to an adamantyl group. The crystalline unit cell is shifted from orthorhombic to triclinic, depending upon the nature of the precision branch. Further, the branch can be positioned either in the crystalline phase or in the amorphous phase of polyethylene, a morphology change dictated by the size of the precision branch. This level of morphology control is accomplished using step polymerization chemistry to produce polyethylene rather than conventional chain polymerization techniques. Doing so requires the synthesis of a series of unique symmetrical diene monomers incorporating the branch in question, followed by ADMET polymerization and hydrogenation to yield the precision-branched polyethylene under study. Exhaustive structure characterization of all reaction intermediates as well as the precision polymers themselves is presented. A clear change in morphology was observed for such polymers, where small branches (methyl and ethyl) are included in the unit cell, while branches equal to or greater in mass than propyl are excluded from the crystal. When the branch is excluded from the unit cell, all such polyethylene polymers possess essentially the same melting temperature, regardless of the size of the branch, even for the adamantyl branch.
