Graphene oxide: a novel acid catalyst for the synthesis of 2,5-dimethyl-N-phenyl pyrrole by the Paal –Knorr condensation

Publication date: April 2017 Source:New Carbon Materials, Volume 32, Issue 2 Author(s): Chun-yan Chen, Xiao-ya Guo, Guang-qiang Lu, Christian Marcus Pedersen, Yan Qiao, Xiang-lin Hou, Ying-xiong Wang Graphene oxide (GO) was used as an efficient and recyclable catalyst for the synthesis of N-substituted pyrrole using a Paal–Knorr condensation reaction between 2,5-hexanedione and aniline. The effects of reaction time, reaction temperature, solvent, catalyst loading and molar ratio of aniline to 2,5-hexanedione on the yield of 2,5-dimethyl-N-phenyl pyrrole were investigated. In situ NMR was used to follow the Paal–Knorr reaction at the molecular level. Results revealed that the oxygen-containing groups of GO, such as sulfonic acid and carboxyl groups, played a key role in this catalytic reaction. Polar protic solvents were favorable for the reaction. The catalytic activity increased with temperature without any side reaction. The GO could be easily recovered and showed remarkable reusability and excellent catalytic performance allowing it to be reused 5 times.

Source: New Carbon Materials - May 26, 2017 Category: Chemistry Source Type: research