We have deeply investigated KNO3-derived silica-supported potassium lactate catalysts for vapour-phase dehydration of lactic acid (LA) to acrylic acid (AA) by catalytic testing, IR spectroscopic monitoring, ammonia temperature-programmed desorption, isopropyl...

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A high AA selectivity of 84% was achieved through an environmentally friendly and sustainable catalytic process.

In this study, we report a series of bimetallic Ni−WOx catalyst for the ring‐opening of THFA into 15PDO. The structure‐performance relationship of the catalysts was discussed based on extensive characterization using techniques such as BET, H2‐TPR, NH3‐TPD, Pyr‐IR, IPA‐TPD‐MS, XRD, XPS and EXAFS/XANES. The acidity measurements show that higher W density leads to the higher amount of acid density, which could be assigned to the creation of Lewis acid sites mainly on the surface of the calcined catalysts. H2‐TPR profiles of Ni−WOx catalysts show that there is a strong interaction between Ni and W species, enhancing the reducibility of WOx. XRD measurements of calcined Ni−WOx catalysts reveal that the dispersion of Ni particles is enhanced after addition of WOx species. After reduction, different peaks corresponding to metallic Ni and WO3−x are identified for 10Ni−WOx catalysts, as well as new peak assigned to Ni−W intermetallic phase on 10Ni−30WOx catalyst. The formation of Ni−W intermetallic phase was further proved using XPS and EXAFS studies. THFA hydrogenolysis was also conducted under aqueous‐phase conditions over Ni−WOx catalysts, yielding up to 47 % selectivity to 15PDO, along with a highest combined C5 polyols (i. e., 15PDO and 125PTO) selectivity of approximately 64 %. However, the Ni−WOx catalytic system suffers from deactivation process due to the hydrothermal dissolution of the active phase. Further investigation reveals the better stability of metallic tungsten and Ni−W intermetallic phase (Ni4W) against leaching since their corresponding peaks in the XRD patterns of spent catalysts remains nearly unchanged. Finally, 1,4‐dioxane as an organic solvent was employed in THFA hydrogenolysis reaction, resulting in different product distribution, with a THP yield of around 54 %. The catalyst crystalline structure is preserved because of very low Ni and W leaching when 1,4‐dioxane is used as solvent.

Crystal structure determination is the key to a detailed understanding of crystalline materials and their properties. This requires either single crystals or high‐quality single‐phase powder X‐ray diffraction data. The present contribution demonstrates a novel method to reconstruct single‐phase powder diffraction data from diffraction patterns of mixtures of several components and subsequently to determine the individual crystal structures. The new method does not require recourse to any database of known materials but relies purely on numerical separation of the mixture data into individual component diffractograms. The resulting diffractograms can subsequently be treated like single‐phase powder diffraction data, i.e. indexing, structure solution and Rietveld refinement. This development opens up a host of new opportunities in materials science and related areas. For example, crystal structures can now be determined at much earlier stages when only impure samples or polymorphic mixtures are available.

The inter-conversions of platinum carbonyl dianionic clusters, ([Pt(3)(CO)(6)](n)(2-), n = 2-5), have been studied in THF and acetonitrile using in situ FTIR spectroscopy. These inter-conversions were facilitated by the addition (or removal) of molecular hydrogen. The individual reactions, namely reductions and oxidations of [Pt(3)(CO)(6)](n)(2-) were fast and reversible. BTEM analysis of the data provided the pure component spectra of the individual species without the need for physical separation. It is shown, for the first time, that the species [Pt(3)(CO)(6)](n)(2-) (n = 2) can be formed from the reduction of [Pt(3)(CO)(6)](n)(2-) (n = 3-5) by hydrogen alone in acetonitrile. Also, detection of dissolved CO(2) in solution suggests that a room-temperature water gas shift reaction occurs. This has been shown to arise from nucleophilic attack of water on a coordinated CO of [Pt(3)(CO)(6)](n)(2-) which leads to the formation of [HPt(15)(CO)(19)](3-) and [H(2)Pt(15)(CO)(19)](2-). The parent tetraanion, [Pt(15)(CO)(19)](4-), has been isolated in high yields by reaction of [Pt(3)(CO)(6)](n)(2-) (n = 2, 3) with NaOH at 60 °C and has been structurally characterized by X-ray analysis.

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