Brønsted Acid Ionic Liquids (BAILs) as Efficient and Recyclable Catalysts in the Conversion of Glycerol to Solketal at Room Temperature

Abstract

Brønsted acid ionic liquids (BAILs) have been prepared and applied for the first time -to the best of our knowledge -as efficient catalysts in the acetylation of glycerol with acetone to form solketal ((2,2-dimethyl-1,3-dioxolan-4-yl)methanol) at very mild reaction conditions (room temperature) and short reaction times. The BAILs showed a superior catalytic performance in terms of both conversion and selectivity compared to the common mineral acid methanesulfonic acid as well as to other reported homogeneous and heterogeneous catalysts. Catalyst reusability was demonstrated with one of the BAILs (BAIL-1), which was recovered and reused by a simple procedure in four consecutive reaction runs without any loss of catalytic activity and selectivity. Thus, the BAILs combine the advantages of both homogeneous and heterogeneous catalysis with respect to excellent conversion and selectivity as well as easy recyclability.

Selective Oxidative Carbonylation of Aniline to Diphenylurea with Ionic Liquids

“…In catalysis, ILs can be used as both the reaction medium and the catalyst and provide beneficial effects, such as high stability towards oxidation by O 2 . In addition, ILs can be functionalized easily for specific catalytic applications –…”

“…The influence of the oxidant is important for oxidative carbonylation. O 2 is preferred as a green oxidant but some safety issues have to be considered, that is, choice of organic solvent because of peroxide formation (e.g., THF or 1,4‐dioxane) and concentration of O 2 in the CO/O 2 mixtures to avoid potential explosive hazards . With this in mind, O 2 , I 2 , and 1,4‐benzoquinone (BQ) were selected as oxidants in the study.…”

Iron(III) Complexes for Highly Efficient and Sustainable Ketalization of Glycerol: A Combined Experimental and Theoretical Study

“…These results are extremely competitive with the previously discussed literature reports. According to literature data, the benzaldehyde ketal consisted of a mixture of the fiveand six-membered products, 39 as revealed by the NMR spectrum in deuterated methanol. As expected, 69 less satisfying were the outcomes of the catalysis with cyclopentanone (entry 4).…”

“…15,25,26,40 1.2:1 β-zeolite (19% wt) 70 °C, 1 h 3 24 10:1 HPW (1% mol) RT, 2 h 4 25 3:1 MoPO/SBA-15SiO 2 (15% wt) RT, 3 h 5 13 1.5:1 Amberlist-36 (5% wt) 40 °C, 8 h 6 17 6:1 ZrO 2 /SO 4 2− (5% wt) RT, 1.5 h 7 31 10:1 Re/SiO 2 (5% wt) 30 °C, 1 h 8 15 6:1 HPW/SiO 2 (5% wt) 30 °C, 4 h 9 20 1. 19 2:1 Zr,Hf/TUD-1 (3% wt) 80 °C, 6 h 12 33 4:1 montmorillonite (0.7% wt) b 50 °C, 0.5 h 13 23 4:1 carbon−SO 3 H (3% wt) RT, 6 h 14 30 1:1 dealuminated zeolite (5% wt) 30 °C, 0.5 h 15 34 6:1 Cs 2.5 H 0.5 PW 12 O 40 /SiO 2 (5% wt) RT, 0.25 h 16 36 9:1 [Cp*IrCl 2 ] 2 (0.2% mol) 40 °C, 1 h 17 37 6:1 TsOH (1% mol) reflux, 12 h 18 38 4:1 SnCl 2 (1% mol) c 25 °C, 2 h, MeCN 19 40 1:1 FeCl 3 (0.03% mol) reflux, 0.1 h see text 20 39 15:1 Bronsted acid ionic liquid (2.7% mol) d RT, 0. The first target of our work was the choice of a convenient set of modular iron(III) catalysts for the synthesis of solketal.…”

“…The reaction appeal is evidenced by the intense search for effective catalytic systems adhering to the conditions prescribed by the principles of green chemistry, such as atom economy, absence of auxiliaries, and ease of recovery of the catalyst. Most of the known catalysts are heterogeneous, − and only a few examples refer to homogeneous systems. − Furthermore, although some mechanistic hypothesis have been proposed, , theoretical in-depth studies are very rare …”