Catalyst-free Preparation of Melamine-Based Microporous Polymer Networks through Schiff Base Chemistry

Abstract

Recently, the synthesis of organic materials with high porosity has received considerable scientific interest, and various chemical approaches have been applied to the build-up of microporous polymer networks. In a novel catalyst-free process using Schiff base chemistry, melamine has been reacted with various di- and trivalent aldehydes to form a series of highly cross-linked microporous aminal networks with BET surface areas as high as 1377 m(2)/g and a NLDFT micropore volume of up to 0.41 cm(3)/g. It was shown that through the proper choice of the starting compounds the porosity of the final material can be fine-tuned. The materials contain up to 40 wt % of nitrogen and were also found to exhibit high thermal stability. Owing to the cheap and abundant monomers used in this study these networks are promising candidates for large-scale applications in gas storage, gas separation, catalysis, and sensing.

Unprecedented high-temperature CO2 selectivity in N2-phobic nanoporous covalent organic polymers

“…Owing to the presence of an electron-deficient carbon atom, CO 2 is expected to interact with protic electronegative functionalities (for example, amines) leading to a strong chemisorption, while N 2 remains impartial. So far, this simple interaction has led to a plethora of nanoporous polymers where the nitrogen-rich functionalities, such as triazine 1,18 , tetrazole 3 , imidazole 41 , phosphazene 24 , imide 42 and amines 25,43 , are built in. In all these and many other situations 2 , CO 2 -philicity is the main driving force for the CO 2 /N 2 selectivity, without taking into account any chemical architecture that would repel N 2 molecules selectively.…”

“…These mostly organic polymers can easily be designed and constructed via facile synthetic protocols. To date, several crystalline and amorphous nanoporous organic materials with tunable functionality have been developed-namely, COF 14 , PIM 15 , HCP and CMP 16,17 , CTF 18 , PAF 19 , PPN 20 , POF 21 , BILP 22 , EOF 23 , PECONF 24 and COP 25 .…”

Imine-linked conjugated organic polymer bearing bis(imino)pyridine ligands and its catalytic application in C–C coupling reactions

“…3%) occurred at 440 °C in N2 and at 420 °C in air. These results indicate that COP-BIP is more stable than other covalent organic polymers such as triazine-based frameworks (about 410 °C in air) [20], melamine-based polymer (about 400 °C in N2) [8], COF-LZU1 (about 310 °C in N2) [2], and POFs (about 400 °C in N2) [10]. By comparison, a polymer with a N,O,N unit [21], which is different to the N,N,N unit of COP-BIP, is stable at 300 °C in N2.…”

“…The successful design and synthesis of these polymers linked by B-O [3][4][5], C-C [6,7], C-N [8], and C=N [9][10][11][12] bonds have been reported. Recent studies have shown that conjugated organic polymers (COPs) with extended π-conjugation possess high thermal stability and structure diversity [13][14][15].…”

Carbon skeleton doped with Co, N, S and P as efficient electrocatalyst for oxygen evolution reaction

“…A well-defined Co-doped carbonitride framework (i.e., CoCN) was prepared first following a modified method [36]. In brief, melamine was reacted with terephthalaldehyde at the presence of trace cobalt nitrate via a one-step polycondensation reaction.…”