Quantum-chemistry-computing and experimental development of a new n-alkenyl amino propionic and imino di-propionic acids-based gum inhibitor for gasoline

Abstract

We present the quantum mechanics-based understanding about the formation of gums deposits in order to design, and then carry out the experimental synthesis of a detergent-dispersant (DD) gasoline additive base n-alkenyl imino di-propionic acid, obtained in mixture with its precursor base n-alkenyl amino propionic acid, aimed both to inhibit gums deposits within internal-combustion engines and maintain in suspension gums inside gasoline. Density Functional Theory reveals the cohesion among gums agglomerates is mediated mainly through dispersion forces, that is, gums form supramolecular complexes; likewise, their affinity for oxidized metallic surfaces is predominantly due also to the dispersion forces, but intensified through the linking of the gums' oxygens by the exposed metallic-surface irons, which is quantum driven to maximize irons spin through completing the truncated oxygen octahedral coordination, so providing to the gums' adsorption a mixed chemisorption/physisorption character. Additionally, carbons from double bonds C=C or from aromatic rings, as well as aminic hydrogens, contribute by means of weak semicovalent bonds to the gums’ chemisorption too. We take advantage of this acquired knowledge to outline a superior coordination chemistry to that of gums for the above deposits inhibitor, lying on the capability to form either trinuclear-tridentate or binuclear-bidentate surface complexes, reinforced moreover by a six-membered chelate ring containing an iron cation. The additive was lab synthesized by means of an industrial-scale residues-less process, and characterized through 1H and 13C nuclear magnetic resonance along with infrared spectroscopy. The detergent performance, experimentally tested within the intake valve of a single-cylinder engine, shows that the DD additive inhibits up to 93.3% of the gums deposition.