Shuixin Xia

MnO2/graphene oxide: a highly active catalyst for amide synthesis from alcohols and ammonia in aqueous media

Rod-like MnO2 uniformly attached on both side of GO sheets (MnO2/GO) is an efficient heterogeneous catalyst for the synthesis of primary amides from primary alcohols and ammonia as well as from aldehydes or nitriles. Water is the best solvent for these reactions, analytically pure crystals of product could be isolated by simply cooling in ice and this catalyst has excellent recyclability.

Catalytic production of 1,2-propanediol from glycerol in bio-ethanol solvent.

Production of 1,2-propanediol (1,2-PDO) from glycerol hydrogenolysis was carried out in bio-ethanol solvent over small amount of Rh-promoted Cu/solid-base catalysts prepared via layered double hydroxide precursors. It was found that glycerol hydrogenolysis proceeded easily on Rh-Cu/solid-base catalysts than separated Rh and Cu/solid-base. The conversion of glycerol and selectivity to 1,2-PDO over Rh(0.02)Cu(0.4)/Mg(5.6)Al(1.98)O(8.57) reached 91.0% and 98.7%, respectively, at 2.0 MPa H(2), 180 °C. And this catalyst was stable in five consecutive hydrogenolysis tests in ethanol.

Transesterification of Glycerol with Dimethyl Carbonate to Glycerol Carbonate over Na-Based Zeolites

Abstract Glycerol carbonate (GC) was synthesized via transesterification of glycerol with dimethyl carbonate under mild conditions over a series of base zeolites. It was found that the NaY zeolite exhibited a higher selectivity for GC (100%) than heterogeneous bases (such as CaO and SrO) or homogeneous catalysts (such as NaOH and K2CO3). Further experiments over different base zeolites disclosed that this transesterification reaction depended strongly on catalyst structure. Base zeolites with small pore diameter such as 3A, 4A, and NaZSM-5 were inactive, while NaY and Naβ with larger pore diameter exhibited excellent GC yields under mild conditions.

Transesterification of glycerol with dimethyl carbonate over calcined Ca-Al hydrocalumite

Abstract A series of Ca-Al hydrocalumite with different Ca/Al ratios (1–6) were synthesized and used in the transesterification of glycerol with dimethyl carbonate (DMC) to glycerol carbonate (GC) under mild conditions. The calcined Ca-Al hydrocalumites were active with a selectivity toward GC that reached 97% at 93% conversion of glycerol over the sample with Ca/Al = 2 at 70 °C, 3 h, and DMC/glycerol = 3. The glycerol conversion depended mainly on the proportion of strong basic sites in the calcined Ca-Al catalysts. The Ca12Al14O33 phase in the calcined catalysts was stable, but CaO was lost in recycle experiments and thus brought deactivation.

Transesterification of glycerol with dimethyl carbonate over Mg-Al hydrotalcites

Abstract Glycerol carbonate (GC) was synthesized via the catalytic transesterification of glycerol with dimethyl carbonate over a series of Mg-Al hydrotalcites with different Mg/Al ratios (0.5–6) under mild conditions. All catalysts exhibited a high selectivity toward GC. The sample with Mg/Al = 2 exhibited 97.1% of selectivity toward GC and 66.9% of glycerol conversion at 70 °C for 3 h. Characterization results indicated that the activity of calcined Mg-Al hydrotalcites depended mainly on the surface area, pore diameter, and crystallinity.

Multiwall carbon nanotube-pillared layered Cu0.4/Mg5.6Al2O8.6: an efficient catalyst for hydrogenolysis of glycerol

Multiwall carbon nanotube (MWCNT)-pillared layered Cu0.4/Mg5.6Al2O8.6 material with doublet meso-pore channels and higher surface area was fabricated and used in hydrogenolysis of glycerol. The activity of surface Cu in MWCNTs–Cu0.4/Mg5.6Al2O8.6 hybrid is higher than those of Pd- and Rh-promoted Cu0.4/Mg5.6Al2O8.6 catalysts.

Trivalent metal ions M3+ in M0.02Cu0.4Mg5.6Al1.98(OH)16CO3 layered double hydroxide as catalyst precursors for the hydrogenolysis of glycerol

Abstract Trivalent metal ions M3+ in M0.02Cu0.4Mg5.6Al1.98(OH)16CO3 (M = Ru, Re) layered double hydroxides (LDHs) were successfully synthesized by coprecipitation. Bimetallic M-Cu/solid base catalysts with high metal dispersion were obtained after calcination and H2 reduction of these LDH precursors. These catalysts exhibited excellent performances for the hydrogenolysis of biomass-derived glycerol under mild conditions. The catalysts were stable when recycled five times. Characterizations indicated that the addition of Ru or Re enhanced the adsorption and activation of hydrogen on the surface of catalysts, which contributed to the high conversion of glycerol.

A thermally stable and easily recycled core–shell Fe2O3@CuMgAl catalyst for hydrogenolysis of glycerol

Core–shell structured magnetic Fe2O3@CuMgAl layered double hydroxide (LDH) catalysts were synthesized in a facile route and used in selective hydrogenolysis of glycerol. Characterization disclosed that the thermal stability of the LDH framework, the dispersion of Cu and its activity were enhanced simultaneously in the presence of Fe2O3.