Functionalized metal–organic frameworks with strong acidity and hydrophobicity as an efficient catalyst for the production of 5-hydroxymethylfurfural

摘要

In the dehydration of fructose to 5-hydroxymethyl furfural(HMF),in situ produced water weakens the acid strength of the catalyst and causes the rehydration of HMF,causing unsatisfactory catalytic activity and selectivity.In this work,a class of benzenesulfonic acid-grafted metal-organic frameworks with strong acidity and hydrophobicity is obtained by the direct sulfonation method using 4-chlorobenzenesulfonic acid as sulfonating agent.The resultant MOFs have a specific surface area of greater than 250 m^(2)·g^(-1),acid density above 1.0 mmol·g^(-1),and water contact angle up to 129°.The hydrophobic MOF-PhSO_(3)H exhibits both higher catalytic activity and selectivity than MOF-SO_(3)H in the HMF synthesis due to its better hydrophobicity and olephilicity.Moreover,the catalyst has a high recycled stability.At last,fructose is completely converted,and 98.0%yield of HMF is obtained under 120℃ in a DMSO solvent system.The successful preparation of the hydrophobic acidic MOF provides a novel hydrophobic catalyst for the synthesis of HMF.