2026-10-14T22:10:28Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33826636 2026-09-16T00:03:28Z category_4 category_14 category_15 category_272 category_873 category_39 portal_63 item_type_3 month_year_09_2026

Two-Stage Optimization of Oleic Acid Esterification via Response Surface Methodology and Green Chemistry Metrics Selection for Biodiesel from WCO Jesús D. Betancourt de la Paz (24959017) Violeta Y. Mena-Cervantes (1274982) Fidel A. Aguilar-Aguilar (24959020) Fabián S. Mederos-Nieto (24959023) Mario A. González Espinosa (24959026) Luis R. Martínez Castro (24959029) Raúl Hernández-Altamirano (1274985) Biochemistry Molecular Biology Neuroscience Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology used cooking oil minimal yield loss methyl oleate ). kinetic validation showed en 14214 specifications delivering high conversion box – behnken within 90 min reduced material intensity evaluates downstream transesterification combines statistical optimization pretreatment reduced ffa high ffa feedstocks rsm model identified factor (∼ 0 oleic acid ratio ∼ 98 wt 2 </ sub wco biodiesel production ∼ 2 oleic acid 2 wt transesterification provided stage optimization material efficiency 363 min acid esterification 5 wt 12 wt residual ffa ffa ), dominant ffa sustainable alternative sustainability assessment study presents stage strategy scalable pathway reduces energy practical endpoint low e fossil fuels crude glycerol adaptable framework 7 %) Biodiesel production from used cooking oil (WCO) is a sustainable alternative to fossil fuels, but its high free fatty acid (FFA) content (>5 wt %) makes direct basic transesterification difficult. This study presents an integrated two-stage strategy that optimizes the acid esterification of oleic acid (the dominant FFA in WCO) using response surface methodology (RSM, Box–Behnken) and then evaluates downstream transesterification, while reporting green chemistry metrics alongside conversion. The RSM model identified an optimum at a methanol-to-oleic acid ratio of 8.44:1, 2 wt % H₂SO₄, and 363 min. Kinetic validation showed that conversion reaches ∼94% within 90 min and then plateaus, indicating a practical endpoint that reduces energy and time with minimal yield loss. Applied to a WCO feed (8.12 wt % FFA), the pretreatment reduced FFA to ∼2.4 wt %, enabling transesterification of the base to ∼98 wt % FAME with <0.5 wt % residual FFA. The final biodiesel met ASTM D6751 and EN 14214 specifications and exhibited a favorable FAME profile (∼75.6% methyl oleate). Green chemistry analysis clarified the trade-offs of these results, with the esterification showing high theoretical atom economy (∼94%), while the transesterification provided a low E-factor (∼0.26) and high atom efficiency (∼87.7%) in a wash-free gravity settling process with methanol recovery/reuse. Treatment of crude glycerol as a byproduct further improves the material efficiency. The results demonstrate a robust and scalable pathway for WCO biodiesel that combines statistical optimization with sustainability assessment, delivering high conversion with reduced material intensity and waste, and offering an adaptable framework for other high FFA feedstocks. 2026-09-15T00:00:00Z Dataset Dataset 10.1021/acsomega.5c06167.s001 https://figshare.com/articles/dataset/Two-Stage_Optimization_of_Oleic_Acid_Esterification_via_Response_Surface_Methodology_and_Green_Chemistry_Metrics_Selection_for_Biodiesel_from_WCO/33826636 CC BY-NC 4.0