Quantum chemical characterization of zwitterionic structures: Supramolecular complexes for modifying the wettability of oil–water–limestone system

• We model two zwitterionic structures, ZL10 and ZL13, for enhanced oil recovery.
• Geometry, stability, global reactivity indexes, and frontier orbital were calculated.
• We determine the nature of the possible supramolecular interactions.
• The structures studied are more stable than the cocamidopropyl betaine.
• The structures studied are less reactive than the cocamidopropyl betaine.

In this work, we present a quantum chemical study pertaining to some supramolecular complexes acting as wettability modifiers of oil–water–limestone system. The complexes studied are derived from zwitterionic liquids of the types N′-alkyl-bis, N-alquenil, N-cycloalkyl, N-amyl-bis-beta amino acid or salts acting as sparkling agents. We studied two molecules of zwitterionic liquids (ZL10 and ZL13), HOMO and LUMO levels, and the energy gap between them, were calculated, as well as the electron affinity (EA) and ionization potential (IP), chemical potential, chemical hardness, chemical electrophilicity index and selectivity descriptors such Fukui indices. In this work, electrochemical comparison was realized with cocamidopropyl betaine (CPB), which is a structure zwitterionic liquid type, nowadays widely applied in enhanced recovery processes.

The geometry of zwitterionic liquids (ZL) into the simulation cell, these are constituted by polyglycols derived from ethylene oxide and propylene oxide, in conjunction with two hydroxyl groups, alkyl amines, acrylic acid. The interaction between these structures and both calcite surface and asphaltene structure indicates changes in wettability of oil–rock–ZL system.Figure optionsDownload high-quality image (117 K)Download as PowerPoint slide