Study of Green Solvents for Ruthenium Alkylidene Mediated Ring‐Opening Metathesis Polymerization

Abstract

Ruthenium alkylidene mediated ring‐opening metathesis polymerizations (Ru‐ROMP) are evaluated in green chemical solvents to increase their green metrics. The Ru‐ROMP of representative monomers of norbornene, oxa‐norbornene, and cyclooctadiene were compared in reference solvents (tetrahydrofuran and chloroform) and green solvents (2‐methyl tetrahydrofuran, ethyl acetate, dimethyl carbonate, and acetone). The results showed that the use of a green solvent is promising. All green solvents exhibited excellent Ru‐ROMP efficiency while their chain length controls were sensitive to solvents and monomers. Among the candidates, dimethyl carbonate expressed the general applicability of various combinations of monomers and solvents.

Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

“…In a similar way, Shin et al tried to perform ring opening polymerization reactions in various green solvents. Oxa-norbornene monomer was subjected to polymerize in the presence of Ru-catalyst (Scheme b) . As the conversion takes place with high yields in THF, CHCl 3 , 2-MeTHF, EA, DMC, and acetone, it is evident that the greener solvents can be plausible alternatives to the existing solvents.…”

Mechanochemical activation of NHC–CS2 adducts for the generation of N‐heterocyclic carbenes

“… 13,14 For example, treating 1,3‐disubstituted imidazolium salt with a strong base yields the corresponding imidazole‐2‐ylidene which can be either isolated under inert conditions or used in situ for subsequent transformations. Notably, this reaction has also been successfully achieved through ball milling, 15–18 and recent reports demonstrate the in situ transformation to Pd, Cu, Au, and other metal–NHC complexes 19–21 . Another alternative methods for generating NHCs include desulfurization of thioureas using strong reducing agents such as potassium metal (Figure 1b).…”

Synthesis of air‐stable poly(benzonorbornadiene)s via ring‐opening metathesis polymerization

“…and Ru-catalyzed metathesis polymerizations 12,[23][24][25][26] are the representative polymerizations to afford functional polymers with high functional group tolerance in mild conditions. Recently, highly functionalized polymers with structural advantages are reported by using various transition-metal catalysts such as controlled synthesis of helical polymers, [27][28][29][30][31] brush polymers, 32 polyallenes, 33 and polycarbenes.…”

“…Transition‐metal mediated polymerizations provide big advances in polymer science and industrial field. Precisely controlled polymerization techniques have been developed by using various transition‐metals, and Cu‐catalyzed atom transfer radical polymerizations (ATRPs) 18–22 and Ru‐catalyzed metathesis polymerizations 12,23–26 are the representative polymerizations to afford functional polymers with high functional group tolerance in mild conditions. Recently, highly functionalized polymers with structural advantages are reported by using various transition‐metal catalysts such as controlled synthesis of helical polymers, 27–31 brush polymers, 32 polyallenes, 33 and polycarbenes 34 …”