Stabilizing Triglyceride in Methanol Emulsions via a Magnetic Pickering Interfacial Catalyst for Efficient Transesterification under Static Conditions
writer：Hao Zhang, Siyang Yu, Shixiong Cao, Xiaobo Liu, Jun Tang, Lingyu Zhu, Jianbing Ji, and Jianli Wang
keywords：pickering emulsion, pickering interfacial catalysts
source：期刊
specific source：ACS Omega
Issue time：2021年
Pickering乳液體系為在靜態(tài)條件下同時(shí)強(qiáng)化和催化甘油三酯與甲醇的酯交換提供了潛在的平臺(tái)。然而，由于乳化液在反應(yīng)溫度下的穩(wěn)定性較低，實(shí)現(xiàn)具有高生物柴油收率的靜態(tài)酯交換仍然具有挑戰(zhàn)性。本文構(gòu)建了一系列表面親和性相似但密度不同的磁性可回收皮克林界面催化劑(PICs)作為大豆油/甲醇乳液的穩(wěn)定劑。從液滴沉降和催化劑顆粒脫落的角度，對(duì)乳化液體積分?jǐn)?shù)和液滴尺寸的變化進(jìn)行了對(duì)比研究和分析。研究發(fā)現(xiàn)，除了表面親和力外，由于重力對(duì)催化劑在甘油三酯/甲醇乳液中的吸附有不可忽視的影響(特別是在高溫下)，PIC密度對(duì)乳液的穩(wěn)定性也起著關(guān)鍵作用。通過降低密度，精細(xì)改善親油性，優(yōu)化PIC的加入量，得到的大豆油/甲醇乳液在60℃下能保持穩(wěn)定至少12 h，實(shí)現(xiàn)靜態(tài)酯交換，生物柴油收率高達(dá)95.6%。此外，性能最好的PIC可以重復(fù)使用至少7個(gè)周期。這種高效的靜態(tài)酯交換系統(tǒng)為生物柴油生產(chǎn)提供了一種綠色策略。
Pickering emulsion systems provide potential platforms for simultaneously intensifying and catalyzing transesterification between triglyceride and methanol under static conditions. However, realizing static transesterification with high biodiesel yield is still challenging due to low emulsion stability at the reaction temperature. Here, a series of magnetically recyclable Pickering interfacial catalysts (PICs) with similar surface affinities but diferent densities were constructed as stabilizers of a soybean oil/methanol emulsion. The variations in the emulsion volume fraction and viewpoint of droplet settling and catalyst particle shedding. It is found that, expect for surface affinity, PIC density also plays a pivotal role in emulsion stability owing to the non-negligible effect of gravity on catalyst adsorption in triglyceride/methanol emulsion (especially at elevated temperature ). By reducing the density, finely improving the lipophilicity, and optimizing the addition amount of PIC, the obtained soybean oil/methanol emulsion can remain stable for at least 12h at 60℃, enabling static transesterification with a high biodiesel yield of 95.6%. Moreover, the best performing PIC can be reused for at least 7 cycles. This efficient static transesterification system offers a green strategy for biodiesel production.
DOI: 10.1021/acsomega.1c00629
浙江省自然科學(xué)基金項(xiàng)目(LY18B040004)和中國博士后科學(xué)基金項(xiàng)目(2020M671790)資助。