Birch Reduction of Asphaltenes. Synthesis of Hydroasphaltenes

• Published in: Energy & fuels Vol. 33; no. 9; pp. 8040 - 8044
• Main Authors: Billups, W. Edward, Verma, Manjusha, Brinson, Bruce Edward, Vishnyakova, Elena, Alemany, Lawrence B, Shammai, Michael
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.09.2019
• ISSN: 0887-0624; 1520-5029
• DOI: 10.1021/acs.energyfuels.9b01298

Reduction of Ecuadorian asphaltenes by lithium in liquid ammonia (Birch conditions) yields asphaltene salts that can be protonated by tert-butyl alcohol to yield deflocculated hydroasphaltene. Studies were carried out using asphaltenes from both low- and high-viscosity oils. The dimensions of the hydroasphaltenes were determined by atomic force microscopy. Relative to the starting asphaltene, the nominal asphaltene aggregate height of the low-viscosity asphaltene 1 was reduced from 1.3 to 0.7 nm, indicating that the asphaltene was fully exfoliated. The height of the high-viscosity asphaltene 2 was reduced from 4 to 2 nm. 13C nuclear magnetic resonance of the Birch-reduced asphaltenes shows a reduction in aromaticity from 49 to 46%, indicating that a low level of hydrogen was added to the aromatic core during the Birch reduction.