Soybean oil and beef tallow alcoholysis by acid heterogeneous catalysis

• Published in: Applied catalysis. A, General General, 2009-06, Vol.361 (1), p.42-48
• Main Authors: Soldi, Rafael A., Oliveira, Angelo R.S., Ramos, Luiz P., César-Oliveira, Maria Aparecida F.
• Format: Article
• Language: English
• Subjects: Biodiesel; Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Heterogeneous polymeric catalyst; Methanolysis; Sulfonated polystyrene; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2009.03.030

Sulfonated polystyrene compounds (SPS) were synthesized, leading catalytically active polymeric materials with high sulfonation degree. Catalyst performance was evaluated in beef tallow and soybean oil transesterification reactions. The SPS leading to conversion of 85 and 75% for soybean oil and beef tallow in to ethyl esters, respectively, and 94% of the soybean oil methyl esters. Therefore, sulfonated polymeric compounds obtained from linear polystyrene are efficient catalysts. Sulfonated polystyrene compounds (SPS) were synthesized from linear polystyrene (PS), leading to catalytically active polymeric materials with sulfonation degrees between 5.0 and 6.2 mmol SO 3H/g of dry polymer. Catalyst performance was evaluated in beef tallow and soybean oil transesterification with ethanol and methanol. The SPS were used at 20 mol% of –SO 3H groups in relation to the oil mass. Methanol:oil molar ratios of 3:1, 6:1, 9:1, and 100:1 were employed, and the reactions lasted between 3 and 18 h. The SPS samples were insoluble in the reaction media and led to conversions of 85 and 75% of refined soybean oil and beef tallow with a 53 mg KOH/g acid number, respectively. There was an increase in ester production for reactions carried out at higher methanol:oil molar ratio and, in some cases, products with as much as 94% methyl ester content were obtained. Therefore, sulfonated polymeric compounds obtained from linear polystyrene are efficient catalysts for the alcoholysis of refined vegetable oils and raw materials containing high acid numbers.