Basic Ionic Liquid Supported on Mesoporous SBA-15 Silica as an Efficient Heterogeneous Catalyst for Biodiesel Production

Abstract

In the present study, SBA-15 silica-supported basic ionic liquid was prepared through grafting of 4-butyl-1,2,4-triazolium hydroxide onto SBA-15 silica using 3-chloropropyltriethoxysilane as a coupling reagent. The structural properties of the prepared catalysts were investigated by a series of techniques, such as Hammett titration method, elemental analysis, small angle XRD, FT-IR, SEM, TEM, and N2 adsorption–desorption. The characterization results demonstrated that the ionic liquid was successfully tethered on the SBA-15 support, and the hexagonally ordered mesoporous structure of SBA-15 silica was well retained even after the chemical grafting reaction. The so-obtained solid catalyst showed excellent catalytic activities toward the transesterification of soybean oil with methanol to produce biodiesel in a heterogeneous manner. The influences of various transesterification parameters such as the subtract ratio, reaction time, catalyst amount, and catalyst reusability on the oil conversion to methyl esters were investigated systematically. Using this solid catalyst for the transesterification reaction, the high conversion of 95.4% was achieved at reflux of methanol for 8 h when the methanol/oil molar ratio of 20:1 and catalyst loading of 7 wt % were employed. Moreover, the solid catalyst could be recycled for four cycles without significant degradation of catalytic activity.

Mesoporous SBA-15 Silica-supported Diisopropylguanidine: an Efficient Solid Catalyst for Interesterification of Soybean Oil with Methyl Octanoate or Methyl Decanoate

“…The textural properties of the samples were calculated from the N 2 adsorption-desorption isotherms at 196 , as listed in Table 2. For the SBA-15 support, the average pore size was 6.64 nm, and the BET surface area and total pore volume were calculated to be 5.89 m 2 /g and 0.92 cm 3 /g, respectively, which were in accordance with the literature data 34,35 . After immobilization of the guanidine base, as indicated in Table 2, the surface area and pore volume were found to decrease to 263 m 2 /g and 0.52 cm 3 /g, respectively.…”

“…Besides, it is interesting to note that the adsorption-desorption hysteresis occurred at a relative pressure of about 0.75 owing to capillary nitrogen condensation, demonstrating that the materials contain mesoporous structure with high-ordering and relatively uniform pore size 34 . For the SBA-15-pr-guanindine catalyst, the capillary condensation appeared to shift toward lower pressures and the amount of adsorbed nitrogen was reduced in comparison with the parent SBA-15 silica.…”

Cocatalyst‐Free Hybrid Ionic Liquid (IL)‐Based Porous Materials for Efficient Synthesis of Cyclic Carbonates through a Cooperative Activation Pathway

“…[14] Recently,i tw as reported that hydrogen-bond-donor groups such as hydroxyl or carboxyl groups, and cocatalysts with ah ydrogen-bond donor could greatlyi mprove the activity of IL-based catalysts. [18] ILs and IL-based polymers have been supported on mesoporouss ilicas, such as SBA-15 and MCM-41. The heterogenization of ILs onto polymer networks is an efficient way to prepare IL-based solid catalysts.…”

Ionic liquids and supercritical carbon dioxide: green and alternative reaction media for chemical processes

“…Immobilizing ILs on the solid surface by chemical grafting is an effective way to solve the leaching problem. Xie et al (2015) prepared a SBA-15 silica-supported basic IL through grafting of 4-butyl-1,2,4-triazolium hydroxide onto SBA-15 silica using 3-chloropropyltri ethoxysilane as a coupling reagent. The IL was successfully tethered on the SBA-15 support, and the hexagonally ordered mesoporous structure of SBA-15 silica was well retained even after the chemical grafting reaction.…”