Preparation of bimodal mesoporous silica containing cerious salt and its application as catalyst for the synthesis of biodiesel by esterification
Preparation of bimodal mesoporous silica containing cerious salt and its application as catalyst for the synthesis of biodiesel by esterification
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DOI：
10.1007/s10934-017-0368-3
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发表时间：
2017-02
影响因子：
2.6
通讯作者：
Jian Li;Haishun Wu;Bo Ma
中科院分区：
文献类型：
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作者：
Jian Li;Haishun Wu;Bo Ma
合成了硫酸高铈铵修饰的双峰介孔二氧化硅催化剂(ACS/BMMS)，并将其应用于游离脂肪酸与乙醇的酯化反应中。X射线衍射仪、氮气吸附脱附仪、FTIR、29Si-核磁共振和透射电子显微镜等表征结果表明，AC/BMMS具有有序排列的双峰型中孔，小的中孔直径在4.0~6.0 nm之间，大的中孔直径在7.0~9.0 nm之间。SiO_2基团Si(OH)_2(Osi)_2与铈盐中的NH_4~+、SO_4~(2+)、−和Ce-O基团之间存在化学作用。当负载量不超过10%时，将铈盐均匀地分散在载体上。以油酸和甲醇为原料进行探针反应，发现ACS/BMMS的活性明显高于ACS/SBA-15、ACS/SBA-16、ACS/MCM-41、BMMS和本体ACS。在催化剂用量为10%，反应温度为140℃，反应时间为2 h，醇酸摩尔比为2.0，催化剂用量为4.0%的条件下，油酸的转化率可达94.0%，催化剂的重复使用性能明显优于本体材料。动力学研究表明，油酸和甲醇在ACS/BMMS催化剂上的酯化反应符合Eley-R模型。
A kind of bimodal mesoporous silica catalyst modified with ammonium cerous sulfate (ACS/BMMS) was synthesized and applied in the esterification of free fatty acid and alcohol. The characterization results including XRD, N2adsorption and desorption, FTIR,29Si-NMR and TEM showed that ACS/BMMS has orderly arranged bimodal mesopores, the small mesopore diameter is about 4.0–6.0 nm and the large mesopore diameter is in the range of 7.0–9.0 nm. The chemical interaction existed between silica group Si (OH)2(OSi)2and the NH4+, SO42−and Ce-O groups of cerious salt. When the loading is not more than 10%, cerious salt dispersed finely on the supports. Oleic acid and methanol were used as the raw material of probe reaction; ACS/BMMS had significantly better activity than the ACS/SBA-15, ACS/SBA-16, ACS/MCM-41, BMMS and bulk ACS. The optimum loading of ACS is 10%, the optimum reaction conditions are reaction temperature 140 °C, reaction time 2 h, mole ratio of methanol to oleic acid 2.0 and the dosage of catalyst 4.0%, in above situation the conversion of oleic acid is about 94.0%, the reusability of ACS/BMMS is much better than bulk ACS. The kinetic study showed that the esterification of oleic acid and methanol on ACS/BMMS match Eley–Rideal model very well.