Heterogeneous Catalysts for the One-Pot Synthesis of Chemicals and Fine Chemicals

Porous organic polymers containing nitrogen-rich building units are among the most promising materials for selective CO2 capture and separation which can have a tangible impact on the environment and clean energy applications. Herein we report on the synthesis and characterization of four new porous benzimidazole-linked polymers (BILPs) and evaluate their performance in small gas storage (H2, CH4, CO2) and selective CO2 binding over N2 and CH4. BILPs were synthesized in good yields by the condensation reaction between aryl-o-diamine and aryl-aldehyde building blocks. The resulting BILPs exhibit moderate surface area (SABET = 599–1306 m2 g–1), high chemical and thermal stability, and remarkable gas uptake and selectivity. The highest selectivity based on initial slope calculations at 273 K was observed for BILP-2: CO2/N2 (113) and CO2/CH4 (17), while the highest storage capacity was recorded for BILP-4: CO2 (24 wt % at 273 K and 1 bar) and H2 (2.3 wt % at 77 K and 1 bar). These selectivities and gas uptake...

Synthesis and Characterization of Porous Benzimidazole-Linked Polymers and Their Performance in Small Gas Storage and Selective Uptake

A highly porous benzimidazole-linked polymer (SABET 1172 m2/g) exhibits very high gas selectivity CO2/N2 (70) and CO2/CH4 (10) and can store CO2 (19 wt %, 273 K, 1 bar) and H2 (1.9 wt %, 77 K, 1 bar) with Qst values of 26.7 and 7.9 kJ/mol, respectively.

Template-Free Synthesis of a Highly Porous Benzimidazole-Linked Polymer for CO2 Capture and H2 Storage

Products of unfavorable chemical equilibria are not readily observed because their high energy and increased reactivity result in low concentrations. Biological macromolecules use binding forces to access unfavorable equilibria and stabilize reactive intermediates by isolating them from the medium. In a similar vein, we describe here a synthetic receptor that allows direct observation of labile tetrahedral intermediates: hemiaminals formed in the reaction of an aldehyde carbonyl group with amines. The receptor encapsulates alkyl-substituted primary amines, then orients them toward a covalently tethered aldehyde function. The hemiaminal intermediates appear at high concentration, confined from the bulk solution and observable at ambient temperature by conventional nuclear magnetic resonance spectroscopy.

https://science.sciencemag.org/content/sci/317/5837/493.full.pdf

Stabilization of labile carbonyl addition intermediates by a synthetic receptor.

An efficient and reusable heterogeneous catalyst Animal Bone Meal for facile synthesis of benzimidazoles, benzoxazoles, and benzothiazoles

A simple and efficient procedure for the synthesis of benzimidazoles using air as the oxidant

Direct one-step synthesis of various benzimidazoles from phenylenediamines and aldehydes is described using air as the oxidant. The salient features of this method include a simple procedure, mild conditions, no coupling agents or commercial oxidants/additives used, no waste produced (only by-product being water), easy purification, and high generality.

Songnian Lin

Papers

A simple and efficient procedure for the synthesis of benzimidazoles using air as the oxidant

A Simple and Efficient Procedure for the Synthesis of Benzimidazoles Using Air as the Oxidant.

Carboxylic Acids — Synthesis from Aldehydes, Ketones, and Derivatives (Including Enol Ethers)