DECHEMA

About: DECHEMA is a nonprofit organization based out in Frankfurt am Main, Germany. It is known for research contribution in the topics: Corrosion & Oxide. The organization has 756 authors who have published 1307 publications receiving 25693 citations.

Towards Small-Scale Continuous Chemical Production: Technology Gaps and Challenges

Abstract: Continuous processes are highly attractive and their advantages are textbook knowledge. However, for small-scale chemical production (typically up to 100 t per year) batch processes are the predominant application. Why this is the case and what factors dominate the decision is analyzed. Apart from technological reasons, socioeconomic, as well as human factors have to be accounted for.

On Activity and Stability of Rhombohedral LaNiO3 Catalyst towards ORR and OER in Alkaline Electrolyte

Abstract: E in oxygen decreased down to 0.57 V thatis the lowest value ever reported in the literature. However, phase segregation and loss in ORR activity was observed during cycling.© The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative CommonsAttribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/),whichpermitsnon-commercialreuse,distribution,andreproductioninanymedium,providedtheoriginalworkisnotchangedinanyway and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0081506eel]All rights reserved.

Catalytic properties of mesoporous crystalline MCM-41 and related materials forhydrocarbon cracking

Abstract: The catalytic properties of extra-large pore aluminosilicate MCM-41 and a silica-containingVPI-5 were investigated by MAT ( M icro A ctivity T est) using n-hexadecane as a model feed and were then compared with the results obtained from a commercial FCC catalyst (FCC: F luid C atalytic C racking) It could be demonstrated that, by optimizing structural and chemical properties, the new mesoporous crystalline MCM-41 and related materials are suitable as active components in cracking catalysts for “deeper” cracking of high boilding hydrocarbons

Formation of bioactive hydroxyapatite-containing titania coatings on CP-Ti 4+ alloy generated by plasma electrolytic oxidation

Abstract: Hydroxyapatite-containing titanium oxide coatings were generated on novel CP-Ti grade 4+ alloys by plasma electrolytic oxidation (PEO) process in two Ca- and P-containing electrolytes. The coatings were obtained under direct current (DC) mode and unipolar pulsed mode at 10 Hz. The effect of the electrolyte composition and the electrical parameters on the coating's performance was investigated. The coatings were characterized with respect to morphology, thickness, and phase formation by scanning electron microscopy (SEM/EDX) and X-ray diffraction. In both electrolytes hydroxyapatite-rich titania coatings could be formed in-situ. The amount of generated hydroxyapatite and perovskite phase depends on the electrolyte composition as well as on the electrical parameters. The coating's corrosion performance was tested in pH 7.0 Hank's solution + 0.1 M H2O2 by open circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Corrosion resistance of coatings generated under unipolar pulsing is increased significantly. Equivalent circuit modelling of EIS spectra indicates a hierarchical PEO coating structure revealing that the enhanced corrosion resistance originates mainly from the inner barrier layer.

Enantioselective enzymatic synthesis of the α-hydroxy ketone (R)-acetoin from meso-2,3-butanediol

Abstract: Acetoin (3-hydroxy-2-butanone) is an important flavour compound and is applied in cosmetics, pharmacy and chemical synthesis. In contrast to chemical syntheses or fermentations an enzymatic route facilitates enantioselective acetoin production. The discovery of a (S)-selective alcohol dehydrogenase enables a novel production process of (R)-acetoin from meso-2,3-butanediol. It was shown that the regeneration of oxidised nicotinamide adenine dinucleotide is a key point in preparative application of dehydrogenases for the oxidative route. An electrochemical regeneration system was successful combined with the ADH catalysed reaction. Up to 48 mM (R)-acetoin was produced in the reaction system while productivities up to 2 mM h−1 were reached. The possibility to apply an electrochemical system in a semi-preparative synthesis will stimulate further research of electroenzymatic processes with oxidoreductases.