Pluronic 123

The periodic mesoporous organosilica denoted PMO-ICS was prepared according to the method introduced by Jaroniec^{122 (link)}. This PMO-ICS was synthesized by self-assembly of tris[3-(trimethoxysilyl)propyl] isocyanurate (ICS, Aldrich), tetraethyl orthosilicate (TEOS, Aldrich) in the presence of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic 123, Aldrich, average Mw ≅ 5800 Dalton) under acidic conditions. In a typical experiment, P123 (2.0 g) was added into a 250 mL beaker and a mixture of deionized water (15 mL) and hydrochloric acid solution (2.0 M, 60 mL) was slowly added and stirred until P123 is completely dissolved. Then, ICS (0.01 mol, 3.08 g) and TEOS (0.03 mol, 3.12 g) were simultaneously added dropwise into the obtained solution. After that, the obtained white gel and precipitates was stirred at room temperature for 24 h in a round bottom flask. Then, the mixture was aged at 100 °C for 48 h without stirring. The solid was filtered off and washed thoroughly with hot EtOH/HCl (60 mL of 96% EtOH and 2 mL of 12.0 M HCl) using a soxhelet apparatus for 72 h to remove the surfactant molecules. The obtained white powder was finally dried in air at 100 °C overnight.

The W-SBA-15 catalyst with the molar ratio of Si:W = 30:1 was obtained using the method described by Chang et al. [8 (link)]. According to this method, 5.51 g of Pluronic 123 (Average Mn ~5800, Aldrich, St. Louis, MO, USA) was dissolved in 179 cm³ of 2 M aqueous solution of HCl. The mixture was then stirred overnight at 35 °C, after which 11.852 g of tetraethyl orthosilicate (98%, Aldrich, Poznań, Poland) was added to it. After 30 min, 9 cm³ of 0.2 M aqueous solution of Na₂WO₄*2H₂O (98%, Angene, Nanjing, China) was added to the reactor. After 24 h of stirring at 35 °C, the mixture was transferred to a Teflon-lined autoclave and kept at 100 °C for 48 h. The contents of the autoclave were then drained under reduced pressure and washed with deionized water and methanol. The resulting material was dried at 60 °C for 24 h and then calcined at 550 °C for 5 h.
The Ti-SBA-15 catalyst with the molar ratio of Si:Ti = 30:1 in the crystallization gel used for comparison of the activity between W-SBA-15 and Ti-SBA-15 materials was obtained according to the method described by Berube et al. [18 (link)].

The Kraft lignin (source: pine wood, CAS no. 8068-05-1, product number: 370959) used in this study was purchased from Sigma-Aldrich. All chemicals and reagent including ethanol (≥98%), ethyl acetate (CH₃COOC₂H₅), ammonium molybdate ((NH₄)₆Mo₇O₂₄·4H₂O), cobalt nitrate (Co(NO₃)₂·6H₂O), pluronic 123, and tetraethyl orthosilicate (TEOS) were also purchased from Sigma-Aldrich (USA, ≥99.5%). All chemicals were used as received without further purification.