甘油衍生的碳基固体酸催化剂的制备及应用

以甘油为原料,首先采用原位炭化和磺化法制备了一种碳材料(CG),再将合成的CG与浓硫酸分别在140、160、180、190℃下磺化2、5、10、12 h得到催化剂SCG-(x)-(y)(其中x为磺化温度,y为磺化时间)。对催化剂进行了XRD、FTIR、TGA、BET、SEM、TEM表征及元素分析,并对催化剂合成过程中的磺化时间和磺化温度进行了探究。以油酸和甲醇的酯化反应为探针反应,研究催化剂的催化活性。结果表明:磺酸基团成功引入到了碳材料表面;随着磺化温度的升高和磺化时间的延长,催化剂表面的磺酸基团数量也随之增加,当磺化时间为10 h、磺化温度为180℃时制备的催化剂具有最优的反应活性。采用间接滴定法对催化剂SCG-(180)-(10)的总酸量进行测定,总酸量高达35 236.21μmol/g。在甲醇与油酸摩尔比12∶1、催化剂用量为原料总质量的5%、反应温度80℃、反应时间0.5 h的条件下,油酸转化率达到98.40%。催化剂重复使用5次,油酸转化率始终保持在90%以上。

Preparation and application of carbon-based solid acid catalyst derived from glycerol

A carbon material( CG) derived from glycerol was prepared by in-situ carbonization and sulfonation process first,and then the synthesized CG was sulfonated with H2 SO4 at 140,160,180,190 ℃for 2,5,10,12 h denoted as SCG-( x)-( y) catalyst( where x was the sulfonated temperature and y was the sulfonated time). The properties of the catalysts were characterized by XRD,FTIR,TGA,BET,SEM and TEM. The sulfonation time and sulfonation temperature in the catalysts ’ synthesis process were investigated. The esterification of oleic acid and methanol was used as probe reaction to study the catalytic activity of the catalyst. The results showed that the sulfonic group was successfully introduced into the surface of carbon materials. With the increase of sulfonation temperature and sulfonation time,the number of sulfonic groups on the surface of the catalyst increased. When the sulfonation time was 10 h and the sulfonation temperature was 180 ℃,the catalyst showed the best reactivity. The total acid content of catalyst SCG-( 180)-( 10) was determined by indirect titration,and the total acid content was up to35 236. 21 μmol/g. Under the conditions of molar ratio of methanol to oleic acid 12∶ 1,catalyst dosage5% of the total mass of raw materials,reaction temperature 80 ℃,and reaction time 0. 5 h,the conversion rate of oleic acid reached 98. 40%. The conversion rate of oleic acid remained above 90%after the catalyst was reused for five times.