Nguyen Ngoc A, Liu Deborah Y, Krogstad Daniel V
Illinois Applied Research Institute, University of Illinois Urbana Champaign, IL, 61801, USA.
Department of Materials Science and Engineering, University of Illinois Urbana Champaign, IL, 61801, USA.
Soft Matter. 2024 Sep 18;20(36):7237-7245. doi: 10.1039/d4sm00809j.
Production of biofuels from biological feedstocks, such as soybean oil, is an important piece of the transition to renewable energy sources. Processes have been developed to co-refine these feedstocks with traditional feedstocks, however, the high concentration of polar functional groups in biofeedstocks can cause a wide range of intermediate chemical reactions and interactions. An improved understanding of the interactions of biofeedstocks and their degradation products is needed to continue to expand the usage of biofeedstocks in fuel production. In this study, the equilibrium structures of glycerol monooleate (GMO), a common intermediate product of biofeedstock processing, in white mineral oil at a wide range of compositions, temperatures, and additional byproduct concentrations (water and/or oleic acid) were characterized using small angle X-ray scattering (SAXS). It was determined that GMO can exist as crystalline aggregates in white oil or as reverse micelles depending on the concentration and temperature. The critical micelle temperature increases significantly with increasing GMO concentration but remains relatively stable with increasing water or fatty acid concentration. Fitting of the SAXS data revealed that for many compositions, the GMO formed roughly spherical reverse micelles, however, at high water concentrations (∼1 wt%), the GMO formed elongated reverse micelles. Additionally, when >1 wt% oleic acid was added to the system, bi-continuous structures were stabilized rather than discreet reverse micelles. These results help increase our understanding of the structural behavior of biofeedstock intermediate products at concentrations and temperatures relevant to biofuel production and can enable processers to design systems and products that can either leverage or prevent these interactions for improved processing performance.
利用生物原料（如大豆油）生产生物燃料是向可再生能源转型的重要环节。人们已开发出将这些原料与传统原料共同精炼的工艺，然而，生物原料中高浓度的极性官能团会引发一系列中间化学反应和相互作用。为了继续扩大生物原料在燃料生产中的应用，需要更好地理解生物原料及其降解产物的相互作用。在本研究中，使用小角X射线散射（SAXS）对生物原料加工的常见中间产物甘油单油酸酯（GMO）在白矿油中的平衡结构进行了表征，该平衡结构涉及多种组成、温度以及额外的副产物浓度（水和/或油酸）。结果表明，根据浓度和温度的不同，GMO在白油中可以以结晶聚集体的形式存在，也可以形成反胶束。临界胶束温度随着GMO浓度的增加而显著升高，但随着水或脂肪酸浓度的增加保持相对稳定。SAXS数据拟合结果表明，对于许多组成，GMO形成大致球形的反胶束，然而，在高水浓度（约1 wt%）下，GMO形成拉长的反胶束。此外，当向体系中添加>1 wt%的油酸时，双连续结构得以稳定，而非离散的反胶束。这些结果有助于增进我们对生物原料中间产物在与生物燃料生产相关的浓度和温度下结构行为的理解，并能使加工者设计出能够利用或防止这些相互作用以提高加工性能的系统和产品。
