Molecular Survey of Strongly and Weakly Interfacially Active Asphaltenes: An Intermolecular Force Field Approach
Molecular Survey of Strongly and Weakly Interfacially Active Asphaltenes: An Intermolecular Force Field Approach
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DOI：
10.1021/acs.energyfuels.1c02266
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发表时间：
2021-10
期刊：
影响因子：
5.3
通讯作者：
D. A. Ballard;J. Pickering;I. Rosbottom;S. Tangparitkul;K. Roberts;R. Rae;P. Dowding;R. Hammond-R.-Hamm
中科院分区：
文献类型：
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作者：
D. A. Ballard;J. Pickering;I. Rosbottom;S. Tangparitkul;K. Roberts;R. Rae;P. Dowding;R. Hammond-R.-Hamm
基于沥青质的界面活性的亚分级已经开始突出那些具有强界面活性（IAA）的沥青质和剩余的沥青质（RA）之间的关键差异。根据石油组学的方法，确定了两种沥青质馏分的代表性结构，反映了丰富的杂原子基团、碳数、双键当量和单核/多核基序的差异。使用基于原子势的网格搜索方法，沥青质-沥青质和沥青质-溶剂（水、庚烷和甲苯）之间的分子间相互作用被快速筛选，以确定最有利的，因此最有可能发生的分子间相互作用。IAA的沥青质-水相互作用（丰度加权平均相互作用能为−9.29 kJ/mol）比RA（−6.32 kJ/mol）更强，IAA-H2O相互作用中的氢键更重要。IAA-IAA的二聚体相互作用强于RA-RA，并且在前100个最有利的相互作用中，RA-RA对总相互作用能的贡献几乎完全是货车德瓦耳斯（仅3%静电），而IAA-IAA，静电相互作用（9%）和氢键（2%）是最有利的相互作用的重要贡献者。随着静电相互作用的相对贡献增加，二聚体取向不太类似于π-π堆叠。随着石油组学和大型结构数据库的概念，网格搜索方法是一种有用的原子/分子筛选方法，它提供了一个理想的分类工具，以快速评估广泛的不同分子结构和相互作用。该方法是对不适合这种工作流程的计算更昂贵的精确分子建模工具的补充。
Subfractionation of asphaltenes based on their interfacial activity has begun to highlight critical differences between those asphaltenes that are strongly interfacially active (IAA) and the remaining asphaltenes (RA). Following the methods of petroleomics, representative structures of the two asphaltene fractions were determined, reflecting differences in abundant heteroatom groups, carbon number, double-bond equivalents, and single-core/multicore motifs. Using atomistic-potential-based grid-search methods, the intermolecular interactions between asphaltene–asphaltene and asphaltene–solvent (water, heptane, and toluene) were rapidly screened to identify the most favorable and therefore most likely intermolecular interactions to occur. Asphaltene–water interactions were stronger for IAA (abundance-weighted average interaction energy of −9.29 kJ/mol) than for RA (−6.32 kJ/mol), with hydrogen bonding more significant in the IAA–H2O interaction. Dimer interactions of IAA–IAA were stronger than RA–RA, and from the top 100 most favored interactions, the contribution to the total interaction energy was almost exclusively van der Waals for RA–RA (only 3% electrostatic), while for IAA–IAA, electrostatic interactions (9%) and hydrogen bonding (2%) were significant contributors in the most favored interactions. As the relative contribution of the electrostatic interaction increased, the dimer orientation less resembled that of a π–π stack. With the conception of petroleomics and large structural databases, the grid-search method is a useful atomic/molecular screening approach that provides an ideal triaging tool to rapidly assess a wide range of different molecular structures and interactions. The method is complementary to the more computationally expensive precision molecular modeling tools that are not suited to such workflows.