Basified Graphene Oxide and PPO Composite Aerogel with Basified Graphene Oxide for Henry Reaction in Solvent-Free Conditions: A Green Approach

Abstract

Novel basified graphene oxide and high-porosity monolithic composite aerogels of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) containing basified graphene oxide (b-eGO) have been prepared as recoverable and reusable catalysts for the Henry reaction in solvent-free conditions at room temperature. The results showed that, although b-eGO was able to promote the reaction, it suffered from reduced stability. On the other hand, PPO/b-eGO aerogels were able to efficiently promote the Henry reaction in solvent-free conditions. The product could be obtained pure without a purification step, and the catalyst was stable for over 15 months and could be easily recycled without losing catalytic efficiency. The stereochemical outcome was further investigated in the presence of PPO/b-eGO. Despite its negligible influence on diastereoselectivity, better efficiency and a sensible reduction of reaction time were observed.

Sustainable functionalization of carbon black via dry ball milling

“…3B). This behavior is possibly due to the evolution of basified oCB in a more thermodynamically stable system with restoring the aromatic structure as previously reported in precedent papers 37,38 and the formation of free salts easily removed by water solution (see ESI†).…”

“…As can be seen in oCB/TPP 1/3 , the relevant reduction in vibration associated with the carboxylic group at 1720 cm −1 , which is evident in oCB, is possibly due to a secondary reduction reaction expected under alkaline conditions. 37 There is, instead, a loss of epoxide stretching at 800 cm −1 due to the opening of the epoxy ring, which provides two nucleophilic sites for quaternary salt functionalization (see Scheme 2). Interestingly, the elemental analysis of oCB after basification and before the functionalization shows a slight reduction of the O/C ratio from 0.32 of the starting oCB to 0.30 after basification according to the possible mechanism shown in Scheme 2.…”