Study On Solid Acid Catalyst Based On Biomass Charcoal And MOF Framework

Comprehensive and efficient,green and reusable solid acid catalyst has been the focus of researchers.This study is divided into two parts,but both are use sulfonation to prepare the target catalyst.1.In section one,Catalytic esterification of fatty acid with methanol,alkylation of 4-ethylphenol with benzyl alcohol as well as 2-methylfuran with cyclopentanone are of great significant for the production of biofuels.However,the in-situproduced water decreases the acidity of catalyst and induces side reaction,leading to an unsatisfactory catalyticactivityn and selectivity.Herein,a novel biochar-based hydrophobic benzenesulfonic acid is prepared for the firsttime by one-pot sulfonation method of biochar with 4-chlorobenzenesulfonic acid.It has a large specific surface area of 100-400 m2/g,a hydrophobicity with H2Ocontact angle higher than 1100 and a high concentration ofsulfonic acid over 1.0 mmol/g.In the esterification reaction of fatty acid with methanol for synthesis of biodiesel,it shows a higher conversion of 96.0%than sulfonic acid resin amberlyst-15(86.7%)and traditional sulfonated biochar-SO3H(28.0%).In the alkylation reaction of 4-ethylphenol with phenylmethanol/2-methylfuran with cyclopentanone for high-density bicyclic/monocyclic biofuel,its catalytic efficiency with target product yields are 69.4%and 70.5%respectively,which are also higher than that of amberlyst-15(74.3%,49.4%)and biochar-SO3H(14.7%,13.0%).Furthermore,the catalyst is more stable than biochar-SO3H.The preparation of hydro-phobic biochar-based sulfonic acid catalysts not only opens a new way for high-value utilization of biochar,butalso provides a novel efficient catalyst in many acid-catalyzed transformation reactions that the product H2O causes deleterious effects.2.In section two,In the dehydration of fructose to 5-hydroxymethyl furfural(HMF),in situ produced H2O decreases the acidity of the acid catalyst and initiates the rehydration of HMF to levulinic acid,causing unsatisfactory catalytic activity and selectivity.Herein,for the first time,a functionalized metal-organic framework with strong acidity and hydrophobicity is prepared by the direct sulfonation of a metal-organic framework(MOF)with 4-chlorobenzenesulfonic acid.The resultant catalysts have a large specific surface area above 250 m2/g,high acid density of greater than 1.0 mmol/g,and strong hydrophobicity with an H2O contact angle up to 129°.Compared with MOF-SO3H without hydrophobicity,the hydrophobic MOF-PhSO3H exhibits both higher activity selectivity in the synthesis of 5-hydroxymethyl furfural due to its better hydrophobicity and olephilicity.Moreover,the catalyst has a high recycled stability.At last,complete conversion of fructose,and 98.0%yield of HMF is obtained under 120? in a DMSO solvent system.