III International Conference

BIODIESEL PRODUCTION FROM OLEIC ACIDUSING H 3 PW 12 O 40 AND Cs 2.5 H 0.5 PW 12 O 40 AS CATALYSTSPP-II-114Sepúlveda J., Santarosa D. 1 , Mandelli D. 1Instituto de Catalisis y Petroquímica, Universidad Nacional del Litoral, Santiago del Estero2654, Santa Fe, 3000, Argentina1 Pontifícia Universidade Católica de Campinas, Faculdade de Química, Rod. D. Pedro I, km136, Pq. das Universidades, Campinas, SP, 13086-900, BrazilE-mail: dalmo_mandelli@mail.ruEsterification of oleic acid with methanol using H 3 PW 12 O 40 (HPA) or Cs 2.5 H 0.5 PW 12 O 40as catalysts was studied. HPA proved to be a very efficient catalyst at room temperature withthe possibility of being reusable. HPA can be separated from the oleic phase by repeatedwashing with water and precipitation with cesium carbonate. UV-visible spectrophotometryrevealed that HPA was present only in the aqueous phase. XRD measurements showed thatthe keggin structure of the cesium salt was formed. The reaction was carried out at 25-110 °Cwith a (oleic acid/catalyst) weight ratio of 30-100. On the other hand Cs 2.5 H 0.5 PW 12 O 40 can beused directly as an heterogeneous catalyst with good conversions at 90° C. Liquid phasedehydration of 1,4-butanediol was employed for assessing the acidity of the catalysts..Heteropoly compounds are used both as heterogeneous solid and as homogeneoussolution catalyst (1). In this sense there is great interest in replacing hazardous liquid acids(e.g. H 2 SO 4 ) or corrosive Lewis solid acids used in esterification reactions by other moreenvironmentally friendly solid acids (2). Biodiesel, an alternative diesel fuel, is generallysynthesized by the transesterification of natural oils or by direct esterification of free fattyacids present in larger amount of Brazilian natural plants. (3). In the present work acidcatalyzedesterification of oleic acids with methanol was studied over H 3 PW 12 O 40 in thehomogeneous phase or Cs 2.5 H 0.5 PW 12 O 40 as heterogeneous catalyst. The reutilization of theHPA by separation and precipitation into Cs 2.5 H 0.5 PW 12 O 40 was also performed. Using 30 mgde H 3 PW 12 O 40 (HPA), a conversion of 45 % was obtained after 10 h (oleic acid/catalystw/w ≅ 100). The only observed product was methyl oleate. For higher amounts of HPAconversion of 80 % was reached (oleic acid/catalyst w/w ≅ 30). Cs 2.5 H 0.5 PW 12 O 40 (Cs-HPA)was also tested as a heterogeneous catalyst. Its performance was worst than for free HPA, butalso showed good activity. Using an oleic acid/catalyst w/w ratioof 30 a conversion of 30 % is observed after 10 h. Increasing the amount of catalyst,conversion of 45 % was obtained (oleic acid/catalyst w/w ≅ 15). The acidity of the catalystswas estimated from data of dehydration of 1-4-butanediol. HPA showed higher conversion373