{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T13:50:32Z","timestamp":1789739432657,"version":"4.0.1"},"reference-count":40,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,1,30]],"date-time":"2022-01-30T00:00:00Z","timestamp":1643500800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>SiO2-SO3H, with a surface area of 115 m2\u00b7g\u22121, pore volumes of 0.38 cm3\u00b7g\u22121 and 1.32 mmol H+\/g, was used as a transesterification catalyst. Triglycerides of waste cooking oil reacted with methanol in refluxing toluene to yield mixtures of diglycerides, monoglycerides and fatty acid methyl esters (FAMEs) in the presence of 20% (w\/w) catalyst\/oil using the hydrophilic sulfonated silica (SiO2-SO3H) catalyst alone or with the addition of 10% (w\/w) co-catalyst\/oil [(Bun4N)(BF4) or Aliquat 336]. The addition of the ammonium salts to the catalyst lead to a decrease in the amounts of diglycerides in the products, but the concentrations of monoglycerides increased. Mixtures of (Bun4N)(BF4)\/catalyst were superior to catalyst alone or Aliquat 336\/catalyst for promoting the production of mixtures with high concentrations of FAMEs. The same experiments were repeated using DMSO as the solvent. The use of the more polar solvent resulted in excellent conversion of the triglycerides to FAME esters with all three-catalyst media. A simplified mechanism is presented to account for the experimental results.<\/jats:p>","DOI":"10.3390\/molecules27030953","type":"journal-article","created":{"date-parts":[[2022,1,31]],"date-time":"2022-01-31T01:46:08Z","timestamp":1643593568000},"page":"953","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Catalytic Transformation of Triglycerides to Biodiesel with SiO2-SO3H and Quaternary Ammonium Salts in Toluene or DMSO"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0294-5345","authenticated-orcid":false,"given":"Sandro L.","family":"Barbosa","sequence":"first","affiliation":[{"name":"Department of Pharmacy, Universidade Federal dos Vales do Jequitinhonha e Mucuri\u2014UFVJM, R. da Gl\u00f3ria, 187, Diamantina 39100-000, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adeline C. Pereira","family":"Rocha","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Universidade Federal dos Vales do Jequitinhonha e Mucuri\u2014UFVJM, R. da Gl\u00f3ria, 187, Diamantina 39100-000, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7435-3675","authenticated-orcid":false,"given":"David Lee","family":"Nelson","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Universidade Federal dos Vales do Jequitinhonha e Mucuri\u2014UFVJM, R. da Gl\u00f3ria, 187, Diamantina 39100-000, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Milton S.","family":"de Freitas","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Universidade Federal dos Vales do Jequitinhonha e Mucuri\u2014UFVJM, R. da Gl\u00f3ria, 187, Diamantina 39100-000, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ant\u00f4nio A. P. Fulg\u00eancio","family":"Mestre","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Universidade Federal dos Vales do Jequitinhonha e Mucuri\u2014UFVJM, R. da Gl\u00f3ria, 187, Diamantina 39100-000, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stanlei I.","family":"Klein","sequence":"additional","affiliation":[{"name":"Department of General and Inorganic Chemistry, Institute of Chemistry, S\u00e3o Paulo State University\u2014UNESP, R. Prof. Francisco Degni 55, Quitandinha, Araraquara 14800-900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giuliano C.","family":"Clososki","sequence":"additional","affiliation":[{"name":"Department of Physics and Chemistry, Faculdade de Ci\u00eancias Farmac\u00eauticas de Ribeir\u00e3o Preto, S\u00e3o Paulo University\u2014USP, Av. do Caf\u00e9 s\/n, Ribeirao Preto 14040-903, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Franco J.","family":"Caires","sequence":"additional","affiliation":[{"name":"Department of Physics and Chemistry, Faculdade de Ci\u00eancias Farmac\u00eauticas de Ribeir\u00e3o Preto, S\u00e3o Paulo University\u2014USP, Av. do Caf\u00e9 s\/n, Ribeirao Preto 14040-903, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3207-4891","authenticated-orcid":false,"given":"Danilo L.","family":"Flumignan","sequence":"additional","affiliation":[{"name":"Instituto Federal de Educa\u00e7\u00e3o, Ci\u00eancia e Tecnologia de Mato Grosso\u2014IFMT\u2014Campus Cuiab\u00e1, Departamento das \u00c1reas de Base Comum (DABC), Rua Profa. Zulmira Canavarros, 95, Centro, Cuiab\u00e1 78005-200, Brazil"},{"name":"Institute of Chemistry, Center for Monitoring and Research of the Quality of Fuels, Biofuels, Crude Oil and Derivatives\u2014CEMPEQC, S\u00e3o Paulo State University (UNESP), Araraquara 14800-900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7329-5298","authenticated-orcid":false,"given":"Let\u00edcia Karen","family":"dos Santos","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, Center for Monitoring and Research of the Quality of Fuels, Biofuels, Crude Oil and Derivatives\u2014CEMPEQC, S\u00e3o Paulo State University (UNESP), Araraquara 14800-900, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5060-6479","authenticated-orcid":false,"given":"Alexandre P.","family":"Wentz","sequence":"additional","affiliation":[{"name":"Centro Universit\u00e1rio SENAI-CIMATEC, Av. Orlando Gomes, 1845, Piat\u00e3, Salvador 41650-010, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"V\u00e2nya M. Duarte","family":"Pasa","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Ensaios de Combust\u00edveis, Universidade Federal de Minas Gerais, Avenida Ant\u00f4nio Carlos, 6627-Belo Horizonte, Belo Horizonte 31270-901, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Regiane D. Fernandes","family":"Rios","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Ensaios de Combust\u00edveis, Universidade Federal de Minas Gerais, Avenida Ant\u00f4nio Carlos, 6627-Belo Horizonte, Belo Horizonte 31270-901, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,30]]},"reference":[{"key":"ref_1","unstructured":"(2020). 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