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The conversion of glycerol to aromatic hydrocarbons is of great significance from the perspective of reducing dependence on fossil resources and comprehensive utilization of industrial by-products. In this study, Holl-HZSM-5 catalysts with hollow structure was prepared and then modified by Zn, Sn and La by impregnation method for the aromatization of glycerol. The results showed that the hollow structure could broaden the internal space and specific surface area of the HZSM-5, thus prolonged the lifetime. Zn modified Holl-HZSM-5 (Zn-Holl-HZSM-5(IM)) present a preferable catalytic performance: under the conditions of 40 wt% glycerol/methanol solution, reaction temperature of 400 °C at 1 atm, mass space velocity of 0.82 h−1, the yield of BTX was 33.5%, and the catalytic lifetime was 8.5 h. In addition, the different preparation methods were investigated for Zn modified Holl-HZSM-5. It was found that Zn@Holl-HZSM-5 prepared by in-situ method had suitable acid strength, acid distribution and intergranular mesoporous, thus the conversion path of aromatization could be further coordinated, leading to a better catalytic efficiency and longer lifetime. [ABSTRACT FROM AUTHOR]

Catalytic conversion of glycerol to lactic acid has been considered as one of the effective ways to solve the problem of glycerol surplus. In this paper, we reported a facile synthesis of Cu/ZnO/C by direct calcination of Cu-supported zeolitic imidazolate framework(ZIF-8), and the performance of the catalysts for converting glycerol to lactic acid were investigated. The properties of Cu/ZnO/C catalysts were characterized by XRD, BET, SEM and TG techniques. The results showed that nano-copper was distributed uniformly on the porous carbon carrier. The zinc oxide after thermal treatment provided abundant metal active sites and had synergistic effect with nano copper. In addition, the lactic acid selectivity of 84% was obtained at the glycerol conversion of 95.1% at 230 °C, 1.5 MPa and 15% copper loading for 6 h reaction. Moreover, the yield of lactic acid still remained above 80% after being recycled four times. [ABSTRACT FROM AUTHOR]

Using etherification to convert glycerol into biofuel additives is an effective way to solve the current problem of excess glycerol. In this study, a series of environmentally friendly (x)HPW/ZrO2 catalysts were synthesized for the etherification of glycerol and tert-butyl alcohol (TBA). The internal microstructure and acidity analysis of the synthesized samples were derived from BET, XRD, Raman spectroscopy, FTIR, SEM, NH3-TPD and Py-FTIR. The results revealed that the synthesized catalysts retained the complete Keggin structure of phosphotungstic acid (HPW) which supported on it. The (15)HPW/ZrO2 catalyst with suitable structure and acidity had an excellent catalytic effect on the etherification reaction. Driven by the (15)HPW/ZrO2 catalyst, the optimal reaction conditions were determined from parameters of reaction temperature, time, molar rate of glycerol and TBA, and catalyst dosage. 93.2% glycerol conversion and 42.5% selectivity of multi-substituted tert-butyl glycerol ethers (DTBG + TTBG) were obtained under optimal conditions. In addition, even after a total of four consecutive reactions, (15)HPW/ZrO2 catalyst still demonstrated relatively good catalytic activity. [ABSTRACT FROM AUTHOR]

The dehydrogenation and isomerization of glycerol to produce lactic acid is an important way to realize the effective utilization of biodiesel by-products. Currently, precious metal catalysts have been widely used in the preparation of lactic acid from glycerol. In this paper, Cu-supported zeolitic imidazolate framework (ZIF-8) crystals of different loadings were synthesized by the reaction of zinc nitrate, copper nitrate and 2-aminobenzophenone at room temperature, and were applied to the reaction of glycerol to lactic acid. Characterizations including XRD, XPS, SEM, TEM, BET, FT-IR, UV–vis DRS, CO2-TPD and TG were carried out to evaluate the morphology and properties of the catalysts. The results showed that the lattice structure of body centered cubic of the materials was successfully formed, and nano-copper was distributed uniformly on the supports, which provided abundant active alkaline sites. In addition, the catalytic reactions achieved good results under optimum copper loading and reaction conditions, which the glycerol conversion and lactic acid yield can reach 97.5% and 84.2%, respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Preparation of glycerol carbonate from glycerol and CO 2 over polymer catalysts functionalized with ionic liquid groups. Highlights • Several polymer catalysts were prepared and applied for the preparation of glycerol carbonate. • The polymer functionalized with ionic liquid groups presented the best catalytic performance. • Glycerol served as both reactant and co-catalyst during the reaction. • The catalyst was highly recyclable. Abstract In the present work, several DVB-based polymer catalysts were prepared and used for the synthesis of glycerol carbonate (GC) from glycerol carbonylation with carbon dioxide (CO 2). Propylene oxide (PO) was introduced as a coupling reagent into the reaction to disturb the thermodynamics limitation. The characterization results confirmed the successful preparation of the functionalized polymer catalysts. P-DVB-(vIm-BuBr) showed the best catalytic performance among the prepared polymers. The high catalytic activity of P-DVB-(vIm-BuBr) was attributed to the presence of ionic liquid groups in the structure of the polymer. In addition, the preparation method had a significant influence on the catalytic activity of the polymer. Functionalization of the monomer with n-butyl bromide before polymerization could increase the content of ionic liquid groups of the polymer catalysts. During the reaction process, glycerol served not only as a reactant, but also as a co-catalyst to facilitate the coupling of PO with CO 2. P-DVB-(vIm-BuBr) achieved PO conversions as high as 96% and GC yields of 81% under optimal reaction conditions. The catalyst was highly recyclable and maintained its catalytic activity after five reaction cycles. [ABSTRACT FROM AUTHOR]

A series of Ce 1- x Cd x O mixed oxide catalysts prepared by co-precipitation method were tested for synthesis of glycerol carbonate (GC) from glycerol and diethyl carbonate (DEC). The microstructural and physicochemical properties of the bimetal catalysts were characterized by XRD, SEM, TEM, XPS, CO 2 -TPD, N 2 -adsorption, TG-DSC and 1 H NMR. The results show that the spherical particles of CdO were uniformly dispersed on the surface of lamellar CeO 2 . Besides, a noticeable increase was observed in the moderate basic sites concentration, because more oxygen atoms were adsorbed on the bimetal sample surface which was attributed to Ce 4+ doped into CdO lattice. The Ce 0.7 Cd 0.3 O sample annealed at 500 °C was observed with the highest catalytic activity. 96.84% of glycerol conversion and 100% selectivity to GC were obtained over this catalyst under the optimized conditions (5 wt.% catalyst of glycerol, 90 °C, 180 min, glycerol/DEC molar ratio of 1:3). Besides, it was found that the conversion of glycerol carbonate was synergistically accelerated by the moderate and strong basic sites. [ABSTRACT FROM AUTHOR]

Nano-sized HZSM-5 (n-HZSM-5) was synthesized and applied in the aromatization of glycerol. The effects of additives (carboxymethylcellulose sodium, NaCl, sodium alginate, etc.) on the chemical and physic properties of n-HZSM-5 during preparation were investigated. Metal modification was also investigated based on the synthesized n-HZSM-5. The results showed that the addition of carboxymethylcellulose sodium (CMC-Na), NaCl and sodium alginate (SA) led to forming smaller sizes of HZSM-5 and promoted the acid amounts of the catalysts, which increased its catalytic activities for obtaining BTX. The highest BTX yield of ~35% was obtained by SA derived n-HZSM-5, and the life of the catalyst were both obviously promoted by the additives with a highest of ~11 h by γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH-560) derived n-HZSM-5. BTX yields could be improved by 40%by the addition of Zn and Cd in n-HZSM-5 while having little effect on the catalyst life. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of catalysts derived from silicotungstic acid (SiW) intercalated with CuZnFe hydrotalcite-like compounds (HTLCs). • The introduction of SiW significantly improved the selectivity towards 1,3-PDO, owing to the increased number of Brønsted acid sites. • The catalyst intercalating 30 wt.% SiW showed the highest selectivity (22.4%) to 1,3-PDO at 68.9% glycerol conversion. A series of catalysts derived from silicotungstic acid (SiW) intercalated with CuZnFe hydrotalcite-like compounds (HTLCs) via ion-exchange method was prepared and characterized by N 2 -physisorption, XRD, TEM, SEM, H 2 -TPR, FT-IR, and Py-IR spectra. The intercalation of SiW species into CuZnFe HTLCs was confirmed by these characterization techniques, while the catalytic performance was evaluated for glycerol hydrogenolysis. It was found that introduction of SiW significantly enhanced the selectivity towards 1,3-propanediols (1,3-PDO), owing to the increased Brønsted acid introduction, as demonstrated by Py-IR analysis. The catalyst intercalating 30 wt.% SiW showed the highest selectivity (22.4%) to 1,3-PDO at 68.9% glycerol transformation. The catalytic performance was discussed and correlated with the physicochemical properties of these catalysts. The present contribution provides an economical approach to convert surplus glycerol from biodiesel manufacture to valuable propanediols. [ABSTRACT FROM AUTHOR]

As important glycerol derivatives, glycerol carbonate (GC) and glycidol (GD) have attracted increasing attention in recent years. In the present work, a series of new solid base catalysts were developed to catalyze the conversion of glycerol to afford GC and GD. These catalysts were prepared by loading KF on the porous La-Zr solid base catalyst and characterized using a series of methods. A large number of various basic sites were generated upon loading KF onto the La-Zr-600 support. The weak basic sites were assigned to the surface hydroxyl groups produced during the formation of LaOF, while the strong and super basic sites were related to the Lewis base produced due to the interaction between KF and the La-Zr-600 support. A glycerol conversion of 91.77% and a GC selectivity of 99% were obtained over 0.3KF/La-Zr, which displayed the best catalytic performance under the optimal reaction conditions. The excellent activity of these catalysts was attributed to the presence of the strong and super basic sites, which favor the transesterification of glycerol with dimethyl carbonate. The production of GD from GC decarbonylation was unfeasible at low temperature using the newly developed catalysts. A plausible reaction mechanism has been proposed based on the experimental results and characterization. [ABSTRACT FROM AUTHOR]

Hierarchical H[Sn, Al]ZSM-5 zeolites were successfully prepared by hydrothermal method with directly incorporating Sn species into framework of HZSM-5 zeolites followed by alkali treatment. The prepared samples were characterized by XRD, BET, SEM-EDX, TEM, NH 3 -TPD, FT-IR and Py-IR. The results indicate that Sn species were successfully incorporated into HZSM-5 zeolites. The catalytic performances of all prepared zeolites were evaluated by glycerol aromatization. The highest catalytic performance of GTA synthesis was observed with H[Sn, Al]ZSM-5 treated with 0.3 M NaOH (32.1% carbon yield of BTX aromatics and 13 h catalyst lifetime), which was prior to the pure HZSM-5 (17.8% carbon yield of BTX aromatics and 3 h catalyst lifetime). The remarkably improved performance in catalytic activity and stability of H[Sn, Al]ZSM-5/0.3AT zeolitize could be attributed to synergy effect between Sn species doped into HZSM-5 zeolite and the generated micro-mesoporous structure by alkali treatment. [ABSTRACT FROM AUTHOR]