Keggin-structure heteropolyacid supported on alumina to be used in trans/esterification of high-acid feedstocks

Abstract

Heteropolyacids (HPA) with Keggin structures, such as H 3 PMo 12 O 40 (H 3 PMo), have been described as efficient catalysts in trans/esterification reactions due to their tolerance to water and free fatty acids contents, with particularly well-suited characteristics of high proton mobility and stability. The versatile array of HPA is considerably increased when such catalysts are supported onto solid matrices. In this sense, Al 2 O 3 was assessed as support for H 3 PMo to be used in trans/esterification reactions to produce biodiesel from high-acid feedstocks. The catalyst structure was characterized and applied on trans/ esterification reaction of acid oils using ethanol as acyl acceptor. A face centered composite design was employed to conduct the experimental design and results analysis, taking macaw palm oil as study model. The process achieved an optimum level of 99.8% ester content and 4.1 mm 2 s À1 viscosity under the following reaction conditions: 190 C reaction temperature, 50 : 1 ethanol-to-oil molar ratio and 13.0% catalyst concentration. Other tested feedstocks (fungal single cell oil and residual frying oil) were also tested promoting satisfactory results, though the parameters were found to be slightly outside the limits set by the USA (ASTM D6715) standard. The H 3 PMo/Al 2 O 3 catalyst presented good regeneration and can be reused for up to four reaction cycles and requires lower ethanol-to-oil ratio, temperature, and catalyst concentration in comparison with other data from the literature.

Tungsten oxide supported on copper ferrite: a novel magnetic acid heterogeneous catalyst for biodiesel production from low quality feedstock

“…On the other hand, some works developed exhibit more severe conditions of alcohol : oil molar ratio e catalyst loading. 20,49,60,61 However, the application of WO 3 /CuFe 2 O 4 catalyst in the transesterification reaction promoted the production of a biodiesel with an ester content greater than 95%, using milder reaction parameters than most catalysts presented in Table 3 or with similar trend. Therefore, the WO 3 /CuFe 2 O 4 magnetic acid catalyst can be considered an appropriate choice for the biodiesel production process via transesterification.…”

Preparation of sulfonated carbon-based catalysts from murumuru kernel shell and their performance in the esterification reaction

“…12 Several types of heterogeneous acid catalysts have been investigated, including zeolites, 13 sulfated zirconia, 14 anion exchange resin, 15 and heteropoly acids. 16 However, most report problems like low stability, low acid density, and stringent reaction conditions. Contrarily, carbon-based catalysts have advantages such as low preparation cost and high catalytic performance.…”

Opportunities for the Use of Brazilian Biomass to Produce Renewable Chemicals and Materials

“…This is much higher than the soybean, which produces only 500 L per hectare, and around 79.5 % of the MO oil contains unsaturated fatty acids [177,221] . The MO transesterification reaction to produce biodiesel can be performed with methanol or ethanol, using aluminium oxide, niobium oxide or activated carbon fibre as catalysts [222] …”

“…[177,221] The MO transesterification reaction to produce biodiesel can be performed with methanol or ethanol, using aluminium oxide, niobium oxide or activated carbon fibre as catalysts. [222] MO like other vegetable oils can be reacted with peracid to synthesise epoxidized compounds. [177] Quirino et al synthesised a polyol derivative by reacting epoxidized MO with formic acid and water.…”