Ti-incorporated SBA-15 mesoporous silica as an efficient and robust Lewis solid acid catalyst for the production of high-quality biodiesel fuels

Abstract

One-pot synthesized Ti-SBA-15 mesoporous materials with various Ti loadings of 0.808-6.78 mol% were applied as heterogeneous solid acid catalysts for simultaneous esterification and transesterification of vegetable oils with methanol into high-quality biodiesel fuel (BDF) at 200 o C under autogeneous pressure. According to the diffuse-reflectance (DR) UV-Vis spectra, diffuse-reflectance infrared Fourier transform (DRIFT) spectra and pulsed ammonia (NH 3 ) chemisorption studies combined with other conventional characterizations, the catalytically active site for high-quality BDF synthesis was mostly related to the tetrahedral Ti 4+ species with weak Lewis acid character, which differential heat of NH 3 adsorption was lower than 90 kJ mmol -1 . Due to that the tetrahedral Ti 4+ species were accessible on largely mesoporous framework, the Ti-SBA-15 catalyst gave much higher activity in transesterification of crude Jatropha oil (CJO) with methanol than microporous titanosilicate of TS-1 and commercial TiO 2 nanocrystallites. Among them, the 3Ti-SBA-15 catalyst with a Ti loading of 2.46 mol% showed a highest fatty acid methyl ester (FAME) content of 90 mass% at 200 o C for 3 h using a methanol-to-oil molar ratio of 27. When the reaction period and methanol-to-oil molar ratio were increased to 3-6 h and 108, respectively, a great variety of edible and non-edible vegetable oils with various acid values (0.06-190 3 mg KOH g -l ), including refined soybean oil (RSO), refined rapeseed oil (RRO), waste cooking oil (WCO), crude palm oil (CPO), CJO and palm fatty acid distillates (PFAD), was directly transformed into high-quality BDFs, which met with a European standard (EN 14214:2009), over 3Ti-SBA-15 catalyst at 200 o C. The used 3Ti-SBA-15 catalyst was easily regenerated by calcination and its high activity was maintained. Most importantly, the 3Ti-SBA-15 catalysts could resist 5 wt% of water or 30 wt% of free fatty acid (FFA), which tolerance levels were several ten times better than those of homogeneous and heterogeneous catalysts in the current BDF production technology.

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

“…Obviously, all composites exhibit the type IV isotherm except 5%WTS0.7 basing upon the IUPAC classification and type H1 hysteresis loop at relative pressure P/P 0 ranging from 0.5 to 0.8, indicative of uniform mesoporous structures with hexagonal cylindrical pores at the capillary condensation step [42]. In addition, the hysteresis loop widely covers at P/P 0 region beyond P/P 0 = 0.8, associating to the intra-aggregate voids of TiO 2 nanocrystallines [43]. Specific surface area, pore volume and pore diameter of all WTS samples are listed in Table 1.…”

Evaluation of synthesized green carbon catalyst from waste date pits for tertiary butylation of phenol

“…Due to a high density, mechanical strength, and porous nature with porous transport channels, activated carbon can be used as adsorbent and catalyst support for acid catalyzed reactions [16][17]. There are several heterogeneous catalysts, such as metal oxides, metal sulfide, zeolite sieves, heteropoly acids, ion exchange resins, and clay; but none of these mentioned catalysts has been found suitable for acid catalyzed reactions due to several facts, such as leaching, internal mass transfer limitation, and deactivation due to carbon deposition on sites [13,[18][19][20][21]. So, waste biomass-derived carbon catalysts are the best alternatives as they possess a large specific area, and a wide range of pore size.…”

A green sulfonated carbon-based catalyst derived from coffee residue for esterification

“…Because of environmental concerns and need for sustainable development, heterogeneous acid catalyst for esterification have been proposed during the past few years, including Br€ onsted acid catalysts [4e7], Lewis acid catalysts [8], and mixed Br€ onsted and Lewis acid catalysts [9e11]. There have been numerous research efforts to develop novel solid acid catalysts in terms of activity, selectivity, reusability, stability, and reproducibility for use in simple and economical processes [12e14].…”