Tandem ROMP/Hydrogenation Approach to Hydroxy-Telechelic Linear Polyethylene

Abstract

Hydroxy-telechelic polyalkenamers have long been synthesized using ring-opening metathesis polymerization (ROMP) in the presence of an acyclic olefin chain-transfer agent (CTA); however, this route typically requires protected diols in the CTA due to the challenge of alcohol-mediated degradation of ruthenium metathesis catalysts that can not only deactivate the catalysts, but also compromise the CTA. We demonstrate the synthesis and implementation of a new hydroxyl-containing CTA in which extended methylene spacers isolate the olefin and alcohol moieties to mitigate decomposition pathways. This CTA enabled the direct ROMP synthesis of hydroxy-telechelic polycyclooctene with controlled chain lengths dictated by the initial ratio of monomer to CTA. The elimination of protection/deprotection steps resulted in improved atom economy. Subsequent hydrogenation of the backbone olefins was performed by a one-pot, catalytic approach employing the ruthenium complex used for the initial ROMP. The resultant approach is a streamlined, atom-economic, and low-waste route to hydroxy-telechelic linear polyethylene that uses a green solvent, succeeds with miniscule quantities of catalyst (0.005 mol %), and requires no additional purification steps.

Ruthenium-catalyzed diazoacetate/cyclooctene metathesis copolymerization

“…In addition to the transition metal catalyzed copolymerization of olefins with polar comonomers, [42][43][44][45][46][47][48][49][50] ROMP-mediated copolymerization represents another powerful strategy. 17,51 More importantly, ROMP is capable of producing functionalized high-density polyethylene containing polar functional groups in the main chain, which is not accessible through traditional olefin copolymerization.…”

Tandem polymerization consisting of cyclotrimerization and the Tishchenko reaction: synthesis of acid- and alkali-degradable polymers with cyclic acetal and ester structures in the main chain

“…In fact, multicomponent reactions, such as the Ugi reaction and the Kabachnik-Fields reaction, [1][2][3][4][5] and tandem reactions have been recently applied in polymer chemistry as bond-forming reactions. [6][7][8][9][10][11] An important key to obtaining a high-molecular-weight (high-MW) polymer is the enhancement of the selectivity of the reactions.…”

The synthesis and properties research of functionalized polyolefins

“…39,40 On the other hand, tandem ring-opening metathesis polymerization (ROMP) and hydrogenation represent another powerful strategy to access functionalized polyolefin. 41,42 In 2002, Grubbs and coworkers developed a ring-opening-insertion metathesis polymerization of cycloolefins and diene monomers to prepare a family of copolymers. 43 The advantages of this system are the great tolerance of polar functional groups, the well-defined copolymer structures and the precise control of the copolymer molecular weight.…”