Location: Bio-oils Research
2017 Annual Report
Objectives
Objective 1: Enable, from a technological standpoint, new commercial separation processes for the production of marketable low-cost high-purity fatty acids.
Objective 2: Enable new commercial products derived from fatty acid esters.
Objective 3: Enable new commercial biobased additives for applications in lubricants.
• Sub-objective 3.A. Develop novel and cost-competitive structures of biobased additives and base oils.
• Sub-objective 3.B. Investigate tribological property of novel biobased additives and base oils and use results to optimize the respective chemical structures.
This project is aimed at developing enabling new commercial technologies, processes, and biobased products for various markets including for: remediation (specifically heavy metal remediation to include water treatment/purification); lubricant additives; lubricant base oils; and chemical additives. The technologies and products from this research will be competitive in cost and performance to those currently in the respective markets. The biobased products targeted in this project will result in significant improvements to the U.S. economy and the environment as well as to the safety and health of the American people.
Approach
(1) This approach outlines work to be performed related to a) screening of feedstock oil properties and quality; b) design of the membrane-based process Step 1 to remove polyunsaturated fatty acids and enrich saturated fatty acids/ monounsaturated fatty acid (MUFA) concentrations in fatty acid or fatty acid methyl ester (FAME) mixtures; c) evaluate two techniques for the design of process Step 2 to efficiently separate and enrich individual MUFA (oleic and erucic acids) with high yield and purity; and d) integrate designs for Steps 1 and 2 into a single process to fractionate fatty acid mixtures to produce valuable MUFA with high yield and purity. These items present a series of decision points that will be addressed during the course of the research project.
(2)Recent research within the unit has shown thioalkyl derivatives of vegetable oils can be used in heavy metal remediation applications with the thioalkyl derivatives acting as metal-coordinating agents for silver ions. Building on these successful findings, new compounds featuring sulfur as the source of binding or chelation will be the primary objective. The initial feedstocks to be examined will be monounsaturated fatty compounds. This will be followed by the more chemically challenging di- and tri-unsaturated fatty compounds and, finally, vegetable oils. Emphasis will be placed on industrial oil feedstocks with enhanced sustainability. Additionally, materials from Objective 1, as they become available, will serve as unique, valuable starting materials.
(3a) New biobased additives and base oils will be synthesized from commodity oils and their derivatives. Commodity vegetable oils comprise fatty acids with unsaturation that can be used as reactive sites for chemical modification. In addition to commodity vegetable oils, polymercaptanized soybean oil, which is produced in large quantities from abundant soybean oil and cheap hydrogen sulfide will be used. Other biobased feedstocks to be used in the synthesis include: FAME, obtained from the biodiesel process, especially those with unsaturation on their hydrocarbon chains; esters of fatty acid with various alcohol structures; etc. (3b) The new biobased additives will be first investigated for their compatibility with standard base oils. Additives found to be incompatible will be investigated using various approaches to make them more compatible. Only compatible additives will be allowed into the next phase which involves the investigation of their effectiveness at performing the specific tasks relevant to its application. Additives will be investigated relative to commercial reference additives using established tests for each application. Various concentrations of the additives in each base oil will be prepared and subjected to the respective tests. Based on these results, optimum concentrations of the additives will be determined.
Progress Report
Substantial progress has been made on all the milestones of each objective for the project 5010-41000-175-00D.
Under Objective 1, membranes were tested for durability and effectiveness in combination with organic solvents. Solvents were necessary in the screening of membranes for relative permeation rates of different fatty acids and esters. Screening tests were performed in a pressurized stirred-cell apparatus. Results will be employed in the design and optimization of scaled-up membrane-based separation processes. Training was received to enable the manufacture of polymer membranes in the laboratory to be tested in the stirred cell.
As specified in the milestone for the second year of the project plan of Objective 2, the properties of new derivatives prepared from fatty acid esters were investigated. Besides application for heavy metal remediation in aqueous waste streams and/or industrial effluents, the new derivatives have properties that may render them suitable for other uses including lubricants and related applications. These applications are important because they use environmentally friendly, agriculturally derived, and renewable materials with properties that are competitive to those of existing petroleum-derived products.
Under Objective 3A, significant progress was made in milestone 2. As a strategy to broaden the spectrum of possible applications of polymercaptanized soybean oil (PMSoy) in lubrication, as well as lubrication performance, various chemical modifications were performed. The chemistry of these synthesis processes were investigated and modeled. Such studies allow for understanding the tribochemical reactions that PMSoy may undergo under lubricating conditions and the possible chemical structure of the tribo-products responsible for the performance of the PMSoy and its derivatives.
Under Objective 3B, work on PMSoy was extended to the fatty acid methyl ester (FAME) derivative of PMSoy. A liter scale quantity of this material was synthesized and subjected to chemical and physical property characterization. Tribological investigations are in progress. Similar characterizations on soybean fatty acid methyl ester (SoyFAME), which will be used as the baseline fluid, are also underway. Previous work, which has been published recently, has shown that PMSoy has multi-functional lubricant additive properties capable of providing improved antioxidant, antiwear, and extreme pressure properties. This implies that FAME derivatives may have the potential to provide a lower viscosity version of a multi-functional additive, which will compliment and expand the application range for vegetable oil-based polymercaptanized products. Commercialization of such products will create a new market for soybean and other oilseed crops.
Accomplishments
1. Developed a predictive model for solid deposit formation in fatty acid streams. Cold temperatures can cause the formation of solid deposits in liquid process streams containing mixtures of fatty acid esters. As a result, membrane-based separation and other processes involving fatty acid ester mixtures will not operate at all or operate very inefficiently. In order to remedy this problem, ARS scientists in Peoria, Illinois, developed a mathematical model that can predict the temperature at which solid deposit formation can occur in fatty acid esters liquid process streams. Application of this predictive model will accelerate the design and optimization of efficient and cost-effective processes for enriching and isolating valuable fatty acid esters from liquid process streams.
2. Properties of heavy metal removal agents based on agricultural products. New materials that can be made from common plant oils, such as soybean, corn, or sunflower oils, were tested for their ability to clean up aqueous waste streams and/or industrial effluents. Several metals, among them mercury and silver, were selected for these tests to serve as an example. The results show that the new materials are very effective in reducing the amount of heavy metals in such aqueous waste streams and industrial effluents, being competitive with or better than existing products. Beyond these tests with heavy metals, checking other properties showed that these materials may have other uses; for example, as lubricants. These applications not only provide a new use and the potential for increasing markets for agriculturally-derived products, but also utilize renewable and domestic resources.
3. Ruthenium-catalyzed decarboxylation reaction of oleic acid. ARS scientists in Peoria, Illinois, have investigated the ruthenium-catalyzed decarboxylation reaction of oleic acid. This reaction can provide a route for the synthesis of biobased olefins if the kinetics of the reaction are optimized. The kinetics of the reaction were successfully modelled with a series of ordinary differential coefficients. Good fits were obtained with several sets of kinetic parameters, indicating that the method in general can be applied to understand the reaction mechanism. However, experiments with more reagents where intermediate and final products are monitored is needed to achieve this goal.
4. Iso-oleic acid (iOA) evaluation for use in biobased lubricant formulation. Iso-oleic acid is synthesized from oleic acid (OA) using a USDA patented synthetic procedure, and can be hydrogenated to iso-stearic acid (iSA) using routine procedures. Both iOA and iSA are of great interest in lubrication because of structural features that could potentially impart them with highly improved additive properties relative to OA. ARS scientists in Peoria, Illinois, characterized iOA relative to OA, for its physical, tribological, and additive properties. Neat iOA displayed higher viscosity, better oxidation stability, lower pour point, and lower wear than neat OA. In polyalphaolefin base oil, iOA as additive resulted in improved viscosity index and lower coefficient of friction. Such improvements can provide the incentives for increased utilization of the biobased iOA in lubricant formulations and thereby increase the demand for high oleic soybean and similar oilseed crops.
Review Publications
Knothe, G.H., Razon, L.F. 2016. Biodiesel fuels. Progress in Energy and Combustion Science (PECS). 58:36-59.
Knothe, G.H., Razon, L.F., Madulid, D.A., Agoo, E.M.G., de Castro, M.E.G. 2017. Methyl esters (biodiesel) from Pachyrhizus erosus seed oil. Biofuels. doi: 10.1080/17597269.2016.1275493.
Bantchev, G.B., Moser, B.R., Murray, R.E., Biresaw, G., Hughes, S.R. 2016. Synthesis and characterization of phosphonates from methyl linoleate and vegetable oils. Journal of the American Oil Chemists' Society. 93(12):1671-1682.
Knothe, G., Razon, L.F., Madulid, D.A., Agoo, E.M.G., de Castro, M.E.G. 2017. Fatty acid profiles of Garuga floribunda, Ipomoea pes-caprae, Melanolepis multiglandulosa and Premna odorata seed oils. Journal of the American Oil Chemists' Society. 94(2):333-338.
Knothe, G., Steidley, K.R. 2017. Fatty acid methyl esters with two vicinal alkylthio side chains and their NMR characterization. Journal of the American Oil Chemists' Society. 94:537-549.
Liu, Y., Tu, Q., Knothe, G., Lu, M. 2017. Direct transesterification of spent coffee grounds for biodiesel production. Fuel. 199:157-161.
Biresaw, G., Lansing, J.C., Bantchev, G.B., Murray, R.E., Harry-O'Kuru, R.E. 2017. Chemical, physical and tribological investigation of polymercaptanized soybean oil. Tribology Letters. 65:87.
Doll, K.M., Bantchev, G.B., Walter, E.L., Murray, R.E., Appell, M., Lansing, J.C., Moser, B.R. 2017. Parameters governing ruthenium sawhorse-based decarboxylation of oleic acid. Industrial and Engineering Chemistry Research. 56(4):864-871.
Moser, B.R., Knothe, G., Walter, E.L., Murray, R.E., Dunn, R.O., Doll, K.M. 2016. Analysis and properties of the decarboxylation products of oleic acid by catalytic triruthenium dodecacarbonyl. Energy and Fuels. 30(9):7443-7451.
Tu, Q., Lu, M., Knothe, G.H. 2017. Glycerolysis with crude glycerine as an alternative 3 pretreatment for biodiesel production from grease trap 4 waste: Parametric study and energy analysis. Journal of Cleaner Production. 162:504-511.
Knothe, G.H. 2017. Analysis of biodiesel. In: Meyers, R.A., editor. Encyclopedia of Analytical Chemistry. Hoboken, NJ: John Wiley & Sons, Ltd. p. 1-15. doi: 10.1002/9780470027318.a9586.
Menendez-Bravo, S., Roulet, J., Sabatini, M., Comba, S., Dunn, R.O., Gramajo, H., Arabolaza, A. 2016. High cell density production of multimethyl-branched long-chain esters in Escherichia coli and determination of their physicochemical properties. Biotechnology for Biofuels. 9:215.
