Oxygenated Biofuels from Butanol for Diesel Blends: Synthesis of the Acetal 1,1-Dibutoxyethane Catalyzed by Amberlyst-15 Ion-Exchange Resin

Abstract

The synthesis of 1,1-dibutoxyethane or acetaldehyde dibutylacetal was studied in a batch reactor by reacting butanol and acetaldehyde in a liquid phase, using Amberlyst-15 as the catalyst. The reaction equilibrium constant was experimentally determined in the temperature range 20-40°C at 6 atm, where K a ) 0.00959 exp[1755.3/T (K)]. The standard properties of the reaction at 298.15 K were estimated: ∆H°) -14.59 kJ mol -1 , ∆G°) -3.07 kJ mol -1 , and ∆S°) -38.64 J mol -1 K -1 . Kinetic experiments were performed in the temperature range 10-50°C at 6 atm. A two-parameter kinetic law based on a Langmuir-Hinshelwood rate expression, using activity coefficients from the UNIFAC method, was used. The kinetic parameters are k c ) 2.39 × 10 9 exp[-6200.9/T (K)] (mol g cat -1 min -1 ) and k s,D ) 2.25 × 10 -4 exp[3303.1/T (K)]. The activation energy of the reaction is 51.55 kJ mol -1 . This work is an important step for further implementation of an integrated reaction-separation process, such as a simulated moving-bed reactor.

The role of butanol in the development of sustainable fuel technologies

“…Incorporation of low cetane number additives can decrease the overall cetane number of a fuel, leading to diminished performance. An intriguing alternative is 1,1‐dibutoxyethane which can be synthesized from renewable acetaldehyde and butanol with the aid of a heterogeneous acid catalyst (Scheme ) 39…”

Heteropolyacid-based ionic liquids as effective catalysts for the synthesis of benzaldehyde glycol acetal

“…In addition, acetalization carried out over these acid catalysts also suffered from inherent problems such as highly susceptible to water and excessive amounts of by-products. As such, considerable efforts have been made in developing more durable solid acid catalysts for acetalization of aldehyde with alcohol, for examples, supported Lewis acid [10][11][12], zeolites [13,14], montmorillonites [5,15], and ion exchange resins [16][17][18]. Nonetheless, issues related to product selectivity, environmental safety, spent catalyst disposal, and catalyst recyclability remained as critical challenges for the design and fabrication of highly active catalysts for acetalization.…”

Process Reintensification

“…The mathematical models used to describe the performance of the integrated and coupled PermSMBR for DBE synthesis consider axial dispersion flow for the bulk fluid phase; linear driving force approximation for the inter-and intraparticle mass transfer rates; multicomponent adsorption equilibrium at the adsorbent phase described by the extended Langmuir isotherm model (Graça et al, 2010a); kinetic law based on LangmuireHinshelwood rate expression (Graça et al, 2010b); liquid velocity variations due to reaction, adsorption/desorption, and species permeation; constant porosity and length of the packed bed; membrane concentration polarization; and isothermal operation.…”