Hydrogenation of Poly(1,3-cyclohexadiene)

Abstract

ABSTRACT:The hydrogenation of poly(1,3-cyclohexadiene)s (PCHDs) with various homogeneous catalysts are reported. The initial screening for hydrogenation catalysts was carried out using cyclohexene as a model compound for the monomeric unit in the polymer chain. High conversion for both cyclohexene and 1,4-linked PCHD were found with carbonylchlorohydridotris(triphenylphosphine)ruthenium(II)[RuHCl(CO)(PPh 3 ) 3 ]. The existence of units formed by 1,2-addition (the 1,2-CHD unit) in the polymer chain strongly influenced the extent of hydrogenation of PCHD. Complete hydrogenation of PCHD (polycyclohexane: PCHE) containing 1,2-CHD units was found with the cobalt(III)acetylacetonate[Co(acac) 3 ] /triisobutylaluminium[(i-C 4 H 9 ) 3 Al] system. The PCHE obtained was composed of cyclohexane rings directly connected in the main chain, and had excellent thermal stability.

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“…Recently, poly(1,3‐cyclohexadiene) (PCHD) and its derivatives have attracted increasing attention, because of their physical, chemical, and electrical properties 1–30. The special structure of the main chain with the six‐membered rings directly connected to each other offers a unique characteristic of PCHDs.…”

“…In previous papers,18, 24, 25, 29, 37–39 we reported the first successful example of living anionic polymerization of 1,3‐CHD; homopolymers and block copolymers with a narrow molecular weight distribution, controlled molecular weight, and clear polymer chain structure have been successfully synthesized. Furthermore, an effective control method for the polymer chain structure of PCHD was reported 18, 37.…”

Anionic Polymerization of 1,3‐Cyclohexadiene: Reactivity of Poly(1,3‐cyclohexadienyl)lithium

“…Subsequently, the influence of the microstructure of different PCHDs and their modified derivatives on several physical and chemical properties was revealed by our research. [13][14][15][16][17][18][19][20][21][22][23] For the anionic polymerization of 1,3-CHD, a good initiator is the most important factor in obtaining a high yield and a controlled polymer chain. In previous studies, [10][11][12][13] we discovered that the n-butyllithium (n-BuLi)/N,N,N 0 ,N 0 -tetramethylethylenediamine (TMEDA) system and the sec-butyllithium (s-BuLi)/1,4-diazabicyclo[2,2,2]octane (DABCO) system are very effective initiators for the anionic polymerization of 1,3-CHD.…”

Thermal Degradation of Poly(1,3‐cyclohexadiene) and its Dehydrogenated Derivatives: Influence of a Controlled Microstructure

“…Since the 1950's, PCHD has been recognized as an attractive precursor for the synthesis of a new class of high performance hydrocarbon polymer. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The unique cyclic nature of the repeat unit and the presence of a residual double bond in the cyclic unit has presented opportunities to synthesize interesting derivatives of PCHDs. However, the difficulty in polymerizing PCHD has been a serious problem and has prevented progress in the study of PCHDs.…”