造纸污泥基固体酸催化D-果糖转化为5-羟甲基糠醛

Papermaking sludge-derived solid acid as catalyst for D-fructose dehydration into 5-hydroxymethylfurural

通过高温煅烧造纸污泥制备了生物炭(SBC),然后用对氨基苯磺酸对SBC进行接枝,制备了一种碳基固体酸(S-SBC)催化剂。采用FTIR、XRD、SEM、N_(2)吸附-脱附、XPS对催化剂进行了表征。将该催化剂用于D-果糖转化为5-羟甲基糠醛(HMF)反应,考察了反应时间、反应温度、催化剂用量及溶剂种类、D-果糖含量对HMF收率的影响,并与用杨木为原料且采用相同方法制备的杨木碳基对氨基苯磺酸接枝生物炭催化剂(S-PBC)进行比较。结果表明,S-SBC的催化活性优于S-PBC。S-SBC同时含有由金属离子形成的Lewis酸位点以及—SO_(3)H等形成的Br?nsted酸位点,两种酸位点在催化D-果糖脱水制备HMF的过程中具有协同作用。S-SBC在V(H2O)∶V(二甲基亚砜)=0.5∶4.5混合溶液中130℃下催化反应40 min,HMF收率高达95.2%,连续使用4次后,催化活性没有明显下降。

Biochar(SBC)was prepared by high-temperature calcination of papermaking sludge and then modifided by p-aminobenzenesulfonic acid to obtain a carbon-based solid acid catalyst(S-SBC).The catalyst was characterized by FTIR,XRD,SEM,N_(2)adsorption-desorption and XPS.The catalyst was used to catalyze D-fructose into 5-hydroxymethylfurfural(HMF).The factors affecting the yield of HMF,such as reaction time,reaction temperature,catalyst dosage,solvent type and D-fructose content were investigated.Poplar carbon-based p-aminobenzenesulfonic acid modified biochae(S-PBC)prepared by the same method was compared with S-SBC.The results showed that the catalytic activity of S-SBC was better than that of S-PBC.S-SBC contained both Lewis acid sites formed by metal ions and Brönsted acid sites formed by—SO_(3)H.The two acid sites exhibited a synergistic effect in the process of catalyzing the dehydration of D-fructose to HMF.The yield of HMF was as high as 95.2%under the conditions of mixture solution with V(H2O)∶V(dimethyl sulfoxide)=0.5∶4.5 as solvent,S-SBC as catalyst,reaction temperature 130℃and reaction time 40 min.The catalytic activity of S-SBC did not decrease significantly after being used for four times.