Location: Bio-oils Research
2023 Annual Report
Objectives
Objective 1. Resolving processing technologies to convert low-quality and nonfood feedstocks into value-added biobased products.
Sub-objective 1.A. Develop low-quality (vegetable oil refining wastes, used cooking oils and greases and residual oils from ethanol fermentation) and nonfood feedstocks for conversion to biodiesel and biobased products. Resolve pretreatment processes and eliminate (or minimize) needs for chemical preparation of low-quality and nonfood (LQNF) feedstocks.
Sub-objective 1.B. Resolve final process technologies for converting low-quality and nonfood (LQNF) feedstocks to biodiesel and value-added coproducts.
Objective 2. Enable commercial processing of new versatile biobased products useful in multiple markets.
Sub-objective 2.A. Enable novel and cost-competitive biobased products with unique structures for applications in multiple industrial sectors.
Sub-objective 2.B. Investigate functional property of novel biobased structures for lubrication, remediation, surfactant/detergent, polymers and other applications; apply structure-property models to optimize the chemical structures for multi-functional application.
This project is aimed at enabling new commercial technologies, processes, and multi-functional biobased products applicable in multiple markets without further modification or processing. Where applicable, low-cost feedstocks from cheap process waste streams will be used. Developed products will have applications in environmental remediation, household and industrial surfactants and detergents, lubricant base oils and additives, cleaners and solvents, polymers and plasticizers, and biofuels and biofuel additives. The technologies and products from this research will be competitive in cost and performance to those currently in the marketplace. The biobased products targeted in this project will result in significant improvements to the U.S. agricultural economy and the environment as well as to the safety and health of the American people.
Approach
Biofuels and biobased products are essential for maintaining a sustainable bioeconomy, protecting the environment, and enhancing the health and safety of citizens. Their widespread application requires efficient and cost-effective processing of farm-based raw materials. Achieving this goal will require overcoming complex technological hurdles to reduce manufacturing costs and expand their ranges of application. This research plan will develop technology for the conversion of low-cost ag-based raw materials to biodiesel and value-added bioproducts with applications in multiple markets. Bioproducts from this research will be developed with potential applications in the environmental remediation of heavy metals from waste streams, household and industrial cleaners, surfactants and detergents, biobased lubricant additives and base oils, fire-resistant polymers and plasticizers, and biodiesel and biodiesel additives. This research project is organized in two main objectives.
Objective one is tasked with the goals of expanding the feedstock supply for conversion to biodiesel and developing alternate conversion processes that produce biodiesel with enhanced cold flow properties. Sub-objective 1.A will expand the feedstock by the development of cost-effective pretreatment processes for upgrading low-quality oils and free fatty acids (FFA) obtained from vegetable oil refining wastes, used cooking oils and greases, and sorghum distiller’s dried grain with solubles (DDGS). Sub-objective 1.B will develop alternative processes for converting low-quality and nonfood (LQNF) feedstocks to biodiesel with improved cold flow properties. These processes will be designed to yield biodiesel mixed with co-products in one conversion step where the co-products can act as built-in cold flow improvers.
Objective two is tasked with the development of multi-functional biobased products from waste cooking oil (WCO) and other low-cost feedstocks. The biobased products will have versatile structures that will allow them to perform in multiple application sectors. Sub-objective 2.A will enable the synthesis of cost-competitive biobased products such as phosphonates, thiophosphates, disulfides, gemini surfactants and polyurethanes (PU). Sub-objective 2B will enable the characterization of these materials in multiple application sectors such as lubrication, environmental remediation, surfactants, detergents and polymers. Structure-property models will be applied to allow for the synthesis of optimized structures of multi-functional biobased products.
Progress Report
In support of Sub-objective 1.A, the physical properties of biodiesel made from high oleic acid pennycress oil were studied. Cold flow properties, oxidative stability, kinematic viscosity (thickness), and lubricity (anti-wear) characteristics were measured. The results were compared with the same properties of biodiesel from cress, unmodified (field) pennycress, and low erucic acid pennycress oils. The cold flow and lubricity properties were similar to other plant seed oils with high oleic acid content. This work showed that the high oleic pennycress oil had the potential for utilization as biolubricant base oils and feedstocks for conversion to biodiesel.
In support of Sub-objective 1.B, new compounds were tested as cold flow improver additives for biodiesel. Additives were synthesized from reacting 1) two types of triacylglycerols; and 2) fatty acids or diacids with a branched-chain alcohol. The influence of these additives on the cold flow properties of soybean oil biodiesel were minimal, suggesting that the "small molecule" strategy for synthesizing additives may be ineffective. New approaches such as converting plant seed oils with methanol and butanol to obtain blends of methyl and butyl esters were devised. These types of blended fatty acid esters were shown to possess improved cold flow properties, with respect to methyl esters (alone) obtained from the same plant seed oil feedstock.
In support of Objective 2.A, polymers were synthesized from waste cooking oil (WCO) with phosphorus (P)-containing groups added to the polymer structure ("WCO-P" polymers). The phosphorus atoms in the polymer structure were expected to impart flame-retardant properties without having hazardous effects which caused chlorinated and brominated flame retardants for polymers to be phased out due to their toxicity. Syntheses of polymer intermediates from WCO and waste glycerol were explored to form biobased polyols, which can be used to synthesize polyurethanes and polyesters. Additionally, biobased phosphorus-containing molecules were synthesized. Soft-type polyurethanes and polyesters were obtained from the WCO. The polyesters had better mechanical properties than the polyurethane. The phosphorus-containing biobased polyesters had modestly better flame retardancy than the biobased phosphorus-free polyesters.
In support of Sub-objective 2.B, byproducts of the synthesis of phosphorus-containing biobased materials were studied. It was observed that using benzoyl peroxide (BPO) to initiate synthesis resulted in the release of the carcinogenic benzene as a byproduct. As a result, an alternative initiator ([tert-butyl peroxy]2-ethylhexyl carbonate) was successfully evaluated for the reaction. Since BPO is widely used in acne treatments, gelled nail polishes, and polymer intermediates, some as-purchased BPO-containing acne treatment products were tested for benzene with positive results, indicating a potentially unrecognized health hazard.
Accomplishments
1. High-oleic-acid pennycress oil has similar properties to other plant seed oils for use as a lubricant. Pennycress is under development as a winter cover crop for use in the Upper Midwestern United States. Winter cover crops may be planted between corn and soybean growth-harvest seasons to increase the annual crop production of farmland and reduce soil erosion. ARS researchers in Peoria, Illinois, obtained a sample of high oleic acid pennycress oil from the University of Minnesota and tested its physical properties. The oil was more than 60 percent oleic acid and had better cold flow properties and shelf life than normal (field) pennycress oil. Its lubricity (anti-wear) characteristics were comparable to similar plant seed oils. There is a growing market demand for lubricants formulated with renewable, biobased oils to replace petrochemical-based products. This work showed that high-oleic-acid pennycress oil can fulfill such demands for biolubricants.
2. Demonstrated biobased chemical yields more product than its petroleum-based analogue. Itaconic anhydride is among the top 12 substances made from biomass for conversion to biobased products, such as polymers and pharmaceuticals. Despite the potential of itaconic anhydride, many products are synthesized from maleic anhydride, a better-established petroleum-based reagent. ARS researchers in Peoria, Illinois, subjected itaconic anhydride to the thio-Michael reaction, a robust and highly efficient organic chemical reaction used in the production of many types of products, in a comparative study with maleic anhydride. The results showed the reaction was possible with itaconic anhydride and produced better yields. This demonstrated that biomass-based itaconic anhydride can replace petroleum-based maleic anhydride in this type of reaction. This research is a key step in developing a biobased material to replace a non-renewable petroleum-based compound used in the production of lubricant additives, dispersants, pharmaceuticals, and polymers.
Review Publications
Winfield, D.D., Moser, B.R. 2023. Selective hydroxyalkoxylation of epoxidized methyl oleate by an amphiphilic ionic liquid catalyst. Journal of the American Oil Chemists' Society. 100(3):237-243. https://doi.org/10.1002/aocs.12672.
Bantchev, G.B., Doll, K.M. 2022. Comparative amine-catalyzed thia-Michael reactions of primary and secondary thiols with maleic and itaconic anhydrides and esters. ChemistrySelect. 7(48). Article e202204138. https://doi.org/10.1002/slct.202204138.
Moser, B.R., Dorado, C., Bantchev, G.B., Winkler-Moser, J.K., Doll, K.M. 2023. Production and evaluation of biodiesel from sweet orange (Citrus sinensis) lipids extracted from waste seeds from the commercial orange juicing process. Fuel. 342. Article 127727. https://doi.org/10.1016/j.fuel.2023.127727.
Yosief, H.O., Sarker, M.I., Bantchev, G.B., Dunn, R.O., Cermak, S.C. 2022. Chemical modification of beef tallow for lubricant application. Industrial and Engineering Chemistry Research. 61(27):9889-9900. https://doi.org/10.1021/acs.iecr.2c01207.
