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The Guerbet reaction of ethanol to heavier products was performed over a series of extensively characterized Sr-substituted hydroxyapatites (HAPs) with different (Ca+Sr)/P ratios, and thus different structural, textural, and acid-base properties. The acid-base properties were correlated with the reactivity of the solids and an optimal ratio between the amount of acid and basic sites was determined (ca. 4), whereas the ethanol conversion was mainly depending on the specific surface area of the solids. The stoichiometric 100 mol % Sr-substituted sample (SrAp-100) was especially efficient in higher alcohols production, which can be illustrated by a total alcohol selectivity (76.4 %) higher than that of all the other solids at a 13 % ethanol isoconversion. [ABSTRACT FROM AUTHOR]

1,3-Butadiene is traditionally produced as a byproduct of ethylene production from steam crackers. What is unusual is that the alternative production route for this important commodity chemical via ethanol was developed a long time ago, before World War II. Currently, there is a renewed interest in the production of butadiene from biomass due to the general trend to replace oil in the chemical industry. This review describes the recent progress in the production of butadiene from ethanol (ETB) by one or two-step process through intermediate production of acetaldehyde with an emphasis on the new catalytic systems. The different catalysts for butadiene production are compared in terms of structure-catalytic performance relationship, highlighting the key issues and requirements for future developments. The main difficulty in this process is that basic, acid and redox properties have to be combined in one single catalyst for the reactions of condensation, dehydration and hydrogenation. Magnesium and zirconium-based catalysts in the form of oxides or recently proposed silicates and zeolites promoted by metals are prevailing for butadiene synthesis with the highest selectivity of 70% at high ethanol conversion. The major challenge for further application of the process is to increase the butadiene productivity and to enhance the catalyst lifetime by suppression of coke deposition with preservation of active sites. [ABSTRACT FROM AUTHOR]

CeNi XH ZO Y nano-oxyhydride catalysts were developed for the highly efficient sustainable hydrogen production from ethanol and water in the oxidative steam reforming reaction. After an in situ treatment in hydrogen in the temperature range of 200-300 °C, the cerium-nickel binary mixed oxides became hydrogen reservoirs, which were called oxyhydrides, in the presence of hydrogen species of the hydride nature in the anionic vacancies of mixed oxides. A novel technology was developed for the room temperature hydrogen production by using the chemical energy released from the reaction between CeNi XH ZO Y nano-oxyhydride catalysts and oxygen, which completely converted ethanol specifically at 60 °C (oven temperature) and simultaneously produced hydrogen, carbon dioxide, and carbon monoxide along with small amounts of methane and ethanal. CeNi XH ZO Y nano-oxyhydride catalysts demonstrated excellent catalytic stability, which was attributed to the graphitic filamentous carbon formed during the reaction. The unique activation phenomenon of the reaction (a huge variation in the temperature between the catalyst bed and the oven) was demonstrated in detail. Finally, the correlations among the catalyst properties, the catalytic performances, and the characterizations were thoroughly discussed. [ABSTRACT FROM AUTHOR]

Taking alcohol from the nanobar The cover picture shows the use of nickel and cerium nano‐oxyhydride catalysts in hydrogen production from ethanol in the presence of water and oxygen. In their Full Paper on p. 2207 ff., L. Jalowiecki‐Duhamel et al. describe the characterization and catalytic properties of the nano‐compounds. Hydrogen production (45 mol %) and total conversion of ethanol remain almost constant over at least 75 h time‐on‐stream with only a small energy input (reaction in oven at 60 °C), thanks to the presence of hydride species stored in the solid. [ABSTRACT FROM AUTHOR]

• Zinc-tantalum on mesoporous silica TUD-1 catalyst showed remarkable activity in the conversion of ethanol to butadiene. • Plackett-Burman design identified key synthesis parameters for high productivity. • TUD-1 synthesis parameters compromised between surface area and pore diameter. • Response Surface Methodology identified high performing catalyst composition. The synthesis method of a zinc-tantalum catalyst supported on three-dimensional mesoporous silica with high specific surface area was studied. Its activity in the conversion of ethanol to butadiene was optimized using the Design of Experiment approach. A Plackett-Burman screening design identified the important preparation parameters, notably the ratio of Zn to Ta. It was subsequently optimized using the Response Surface Methodology, affording a highly active catalyst. [ABSTRACT FROM AUTHOR]

The acrolein production from methanol and ethanol mixtures over iron-molybdate-based catalysts was studied. The reaction to acrolein can be described by two successive steps: the first consists on the oxidation of both alcohols into their corresponding aldehydes and the second step is the subsequent aldol condensation of the as-formed aldehydes. The iron-molybdate catalysts were modified by doping with La and Ce (1%mol) in order to improve the aldol condensation step of the process. Series of catalysts were thus synthesized with different Mo/Fe ratios (i.e., 1.5, 2.0 and 2.5) and calcined at three different temperatures (i.e, 350 °C, 400 °C and 450 °C). The best catalytic performance was observed for FeMoCe2.0 (400 °C) for which the acrolein yield reached 42% (T = 320 °C, MetOH/EtOH = 1, GHSV = 3900 h −1 ). Furthermore, all the samples were characterised by TGA-DSC, HT-XRD, XPS, BET, LEIS, XRF, CO 2 -TPD, Pyridine (FTIR) and NH 3 (calorimetry) adsorption. The increase in acrolein yield observed upon La and Ce doping was attributed to acid/base properties modification. [ABSTRACT FROM AUTHOR]

For a sustainable society, it is highly desirable to produce H 2 from renewable sources and with low energy consumption. Functional, cheap and easy-prepared Mg 2 AlNi X H Z O Y nano-oxyhydrides materials were successfully developed from Mg 2 AlNi X O Y nano-composites ex-hydrotalcites. After an in situ treatment in H 2 at low temperature (450 °C), the Mg 2 AlNi X O Y nano-composites (x > 1) become hydrogen reservoirs, called oxyhydrides, with the presence of hydrogen species of hydride nature that can be stored in the anionic vacancies of the solid. Advanced techniques in presence of H 2 including TPR, in situ XRD and INS were used to study the nano-composites with different Ni contents. The Mg 2 AlNi X H Z O Y nano-oxyhydrides (x > 1) are shown to be able to simultaneously provide hydride species and to totally convert ethanol and produce H 2 from a water-ethanol mixture in presence of O 2 , with very low energy input. In complement to the exothermic partial oxidation reaction, the chemical energy delivered from the strong exothermic reaction between hydride species and O 2 is used. The reaction is sustainable because hydride species are replaced and provided by ethanol. [ABSTRACT FROM AUTHOR]

H 2 production from ethanol was studied on a cerium nickel based (CeNi 1 O Y ) catalyst in presence of water (SRE), in presence of oxygen with different concentrations (POE) and in presence of oxygen and water (OSRE). The influence of different parameters was analyzed, such as the reaction temperature, reactants concentration (oxygen/ethanol/water), and in situ pre-treatment in H 2 . At low temperature a high activity i.e., ethanol conversion and H 2 formation can be obtained when the solid is previously in situ treated in H 2 at 250 °C i.e., in the oxyhydride form. Adding O 2 allows increasing ethanol conversion at low temperature. Different physicochemical techniques, including Inelastic Neutron Scattering (INS), were used to characterize the catalyst. An active site based on the formation of anionic vacancies and a mechanism involving a heterolytic abstraction of a hydride species from ethanol are envisaged. [ABSTRACT FROM AUTHOR]

Mixed oxide catalysts composed of mixtures of La 1+ x FeO 3+ δ perovskite and La 2 O 3 were prepared using the auto-combustion method with glycine as an ignition promoter. A series of samples was prepared with x = 0, 0.1, 0.3, 0.5, 0.8 and 1, which were hereafter called La 1+ x Fe. The as-prepared powders were characterized by XRD, XPS, DTA-TGA and N 2 -physisorption. Their acid-base properties were evaluated from their 2-propanol reactivity. Surface enrichment in La 2 O 3 was detected when the lanthanum content increased. For high lanthanum concentrations, lanthanum hydroxide was also formed. The highest ethanol conversion was observed over La 1.3 Fe (32% at 400 °C), which contained the largest amount of basic sites. The main reaction products were ethylene, acetone, 2-pentanone and 1-butanol. Other minor products originating from dehydration, reverse aldolization and hydrogenation reactions were also detected. Such a diversity of products was due to the presence of different kinds and distribution of sites on the catalysts surface (acid, base, hydrogenation, etc. ). The catalysts activity was depending on their acid-base properties: an increase in the basic character due to the La 2 O 3 presence at the surface leaded to higher selectivities to 1-butanol and 2-pentanone, which were 6 and 31% at 400 °C, respectively, over the sample with the highest number of basic sites, which were also stronger (La 1.3 Fe). On the other hand, over La 1.8 Fe, which contained the highest quantity of La(OH) 3, lower selectivities to 1-butanol and 2-pentanone (4.3 and 22%, respectively) were observed due to a decrease in the number of basic sites, together with a high ethylene selectivity (37%), with thus a predominant action of acid sites. [ABSTRACT FROM AUTHOR]

Hydrotalcite-type Mg 6− x Cu x Al 2 (OH) 16 CO 3 ·4H 2 O solids (with x = 0, 1, 3, 5) were synthesized as precursors of mixed oxides obtained by subsequent calcination. Two families of samples (synthesized by coprecipitation with and without sonication) were thoroughly characterized by XRD, TG–TDA, H 2 -TPR, NMR, SEM and N 2 -physisorption. Their reactivity towards ethanol was further assessed. Sonication enabled considerably reducing the preparation duration. MgO and Al 2 O 3 were formed upon calcination of the hydrotalcites under air at 400 °C, while copper-enriched phases ( e.g. CuO, spinel like structure…) were formed from the solids with higher Cu contents. Magnesium atoms substitution by copper atoms in the hydrotalcite structure was evidenced for the first time in this kind of materials using high-resolution solid state NMR. Indeed, a very unusual but remarkable “Fermi contact effect” was responsible for specific features observed on the NMR spectra. Further, partial substitution of magnesium by copper led to an increase in specific surface area, with the formation of particles of a smaller size. Copper addition considerably enhanced the dehydrogenation properties of the solids at low temperature (∼250 °C), with a higher reactivity towards ethanol, and higher selectivities to acetaldehyde. [ABSTRACT FROM AUTHOR]

Inexpensive Ni X Mg 2 AlO Y nanocomposites with high Ni content (Ni wt% > 40%) are developed as efficient catalysts for the sustainable hydrogen production from a mixture of ethanol and water at low temperature. The Ni X Mg 2 AlO Y nanocomposites are composed of small and uniform nanoparticles (4–6 nm) of NiO, Ni–Mg–(Al)–O and/or MgO. The strong interactions existing between Ni 2+ cations and Mg 2+ and/or Al 3+ cations either in the Ni–Mg–(Al)–O solid solution and/or at the interface of nanoparticles of NiO and/or Ni–Mg–(Al)−O make the catalyst highly active and stable. The behavior of the solids is analyzed in the presence of low and high concentrations of ethanol while maintaining a H 2 O/EtOH molar ratio of 3. The Ni X Mg 2 AlO Y catalysts are shown to be efficient toward H 2 production between 250 and 650 °C. In the presence of low concentration of ethanol, on the highly loaded Ni compound (Ni 12 Mg 2 AlO Y ), total conversion of ethanol is obtained at 250 °C without formation of CO and carbon, and at 300 °C a H 2 yield of 3 mol mol EtOH −1 is obtained without the formation of CO, exhibiting a remarkable stability with the time on stream even if some carbon is formed. In high concentration of ethanol, total conversion of ethanol is obtained at 450 °C on the highly loaded Ni compound (Ni 12 Mg 2 AlO Y ). In such conditions, a stable co-generation of carbon nanofibrous materials which amount increases with Ni content is also obtained. The catalytic stability is related to the type and morphology of the carbon species formed. The correlations among the catalyst properties, the catalytic performances and the characterizations are thoroughly discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Co-precipitation method allows obtaining well-tuned NiXMg2AlOY mixed oxides. [•] The effect of Ni content, activation treatment, and reaction conditions are studied. [•] Total conversion of ethanol at 450°C and CO-free H2 production of 3.0molmolEtOH−1. [•] Good catalytic stability even though solid carbon is formed. [•] Active site involves anionic vacancies, O2− species and cations in close interaction. [ABSTRACT FROM AUTHOR]