Exploring Oxidative NHC‐Catalysis as Organocatalytic Polymerization Strategy towards Polyamide Oligomers

Abstract

The polycondensation of diamines and dialdehydes promoted by an N‐heterocyclic carbene (NHC) catalyst in the presence of a quinone oxidant and hexafluoro‐2‐propanol (HFIP) is herein presented for the synthesis of oligomeric polyamides (PAs), which are obtained with a number‐average molecular weight (Mn) in the range of 1.7–3.6 kg mol−1 as determined by NMR analysis. In particular, the utilization of furanic dialdehyde monomers (2,5‐diformylfuran, DFF; 5,5’‐[oxybis(methylene)]bis[2‐furaldehyde], OBFA) to access known and previously unreported biobased PAs is illustrated. The synthesis of higher molecular weight PAs (poly(decamethylene terephthalamide, PA10T, Mn = 62.8 kg mol−1; poly(decamethylene 2,5‐furandicarboxylamide, PA10F, Mn = 6.5 kg mol−1) by a two‐step polycondensation approach is also described. The thermal properties (TGA and DSC analyses) of the synthesized PAs are reported.

Recent advances in the development of green furan ring-containing polymeric materials based on renewable plant biomass

“…170 It should be noted that 2,5bis(aminomethyl) furan, an amino analog of BHMF, can also be involved in such organocatalyzed oxidative polycondensation with different aldehydes, which results in the formation of corresponding polyamides. 171 A mechanochemical approach was used to carry out the reaction between BHMF, 4,4 0 -methylenediphenyl diisocyanate (MDI) and a variety of diols or diamines, resulting in ecofriendly thermoplastic polyurethanes with controllable thermomechanical properties (Fig. 6IV).…”

“…170 It should be noted that 2,5-bis(aminomethyl) furan, an amino analog of BHMF, can also be involved in such organocatalyzed oxidative polycondensation with different aldehydes, which results in the formation of corresponding polyamides. 171…”

Organocatalytic synthesis of poly(hydroxymethylfuroate) via ring-opening polymerization of 5-hydroxymethylfurfural-based cyclic oligoesters

“…At this stage of our study we were interested in the development of a more sustainable and straightforward route to valuable c (HMF) n starting from the platform chemical HMF . Based on our experience in the application of oxidative NHC catalysis as synthetic platform to access bio-based furan polyesters/polyamides 3 c ,25 and HMF upgraded products, 26 we commenced our investigation by considering the polycondensation of HMF (0.13 M, THF) promoted by the triazolium pre-catalyst A (10 mol%) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU; 0.25 mol%) and a stoichiometric amount (1.0 equiv.) of the quinone oxidant 2 (Table 2, entry 1).…”

Reductive Amination of 5‐Hydroxymethylfurfural to 2,5‐Bis(aminomethyl)furan over Alumina‐Supported Ni‐Based Catalytic Systems

“…As an important building block platform, 5-hydroxymethylfurfural (5-HMF) can be transformed into various valued derivatives by the selective tailoring of its active C=O, À OH, and furan ring functional groups, such as 2,5-dimethylfuran, [1][2][3] 2,5dihydroxymethylfuran, [4][5][6] 2,5-bis(aminomethyl)furan (BAMF), [7][8][9] 2,5-diformylfuran, [10][11][12] 2,5-furandicarboxylic acid, [13,14] and other ring-opened compounds. [15,16] Among them, BAMF is considered as a promising bio-based monomer and utilized in the production of several kinds of bio-based polymers, such as polyurethane, polyamine, and polyurea, [17][18][19] with advantages in the gas barrier performance, miscibility, and processability. [20][21][22][23] Besides, the furan-based amine is also a promising intermediate in the pharmaceutical and food industry.…”