Biolubricants derived from Orychophragmus violaceus seed oil

Authors: Winfield, Demichael; Evangelista, Roque; Moser, Bryan; Bantchev, Grigor; Moser, Jill; Cermak, Steven

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/22/2025
Publication Date: 8/1/2025
Citation: Winfield, D.D., Evangelista, R.L., Moser, B.R., Bantchev, G.B., Moser, J.K., Cermak, S.C. 2025. Biolubricants derived from Orychophragmus violaceus seed oil [abstract). Association for the Advancement of Industrial Crops Annual Conference, August 31-September 4, 2025, Fairbanks, AK.

Interpretive Summary:

Technical Abstract: Orychophragmus violaceus (Ov) is a Brassicaceae native to eastern Asia, commonly referred to as February orchid or Chinese violet cress. Wild populations are distributed across China and Korea, and it is grown in many regions across the world as an ornamental plant for its distinct purple flowers. Ov seed oil contains two long chain dihydroxy fatty acids, nebraskanic (7,18-OH2-24:1) and wuhanic acids (7,18-OH2-24:2). The unique fatty acid composition of Ov has led to interest in domesticating it as an oilseed crop in the United States. In this effort, we report the physicochemical properties of Ov oil and its application as a biolubricant. The Ov seeds used in this study contained 42% oil by mass. Cold-pressing of the seeds followed by hexane extraction of the press cake resulted in 39% crude oil yield. The oil was highly unsaturated, with the fatty acid composition primarily comprised of wuhanic (51 wt%), linoleic (20 wt%) and nebraskanic (10 wt%) acids. The antioxidant composition of Ov oil was typical for vegetable oils, with a total tocopherol content of 653 µg g-1 and phytosterol content of 7.22 mg g-1. The kinematic viscosity at 40 °C (KV40) of the oil was 265 mm2 s-1, which was comparable to castor oil. The oil exhibited good oxidative stability with an oxidation onset temperature of 180 °C by PDSC and a Td95 of 314 °C by TGA. Ov oil exhibited desirable properties as a lubricant, with a pour point of -18 °C and superior lubricity compared to petrol-based oils. A series of estolides were prepared from the methyl esters of the Ov oil to further explore the lubricant properties. A highly branched estolide with a high estolide number (En=31.4) was successfully prepared by simple polycondensation of the Ov esters. The KV40 of the estolide was 4,162.4 mm2s-1, which is much higher than what is typically achieved with vegetable oil-derived lubricants. The estolide had moderate thermal stability with an oxidation onset temperature of 161 °C and a Td95 of 312 °C. The estolide also exhibited excellent lubricity and a moderate pour point of -12 °C. The advantageous properties of this estolide could lend itself to applications as an industrial fluid, in which higher viscosities are needed. A series of estolides with varying properties were synthesized by reacting Ov methyl esters and methyl oleate in different ratios, allowing for the properties of the estolide to be tuned by controlling the En. Due to the attractive lubricant properties of the oil and its estolides, Ov could be a good candidate for domestication as feedstock crop. Further studies into the properties of the oil and other derivatives are currently underway.