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.

Die Korrosion von Eisen, Nickel, Kupfer und Aluminium in organischen Lösungsmitteln mit geringem Mineralsäuregehalt

Abstract: Das noch wenig behandelte Gebiet der Korrosion in Saurehaltigen, praktisch wasserfreien organischen Losungsmitteln wird im Dauertauch- und Kochversuch untersucht. Aus den Korrosions-Zeit-Kurven und der Phanomenologie des Angriffs ergibt sich ein Verhalten, das sich in folgenden Punkten vom Korrosionsangriff in entsprechenden wasrigen Losungen unterscheidet: Vergroserung der Korrosionsgeschwindigkeit fur Fe, Ni and Cu in sauren Aethanollosungen und in salzsaurem Aceton; Verringerung der Korrosionsgeschwindigkeit Fur Ni und Cu in Essigsaure und Schwefelsaure; keine Korrosion infolge Bildung von Deckschichten in einigen Systemen mit Aceton als Losungsmittel. Die Grunde fur das unterschiedliche Verhalten werden diskutiert. The corrosion of iron, nickel, copper and aluminium in organic solvents with low contents of mineral acids The subject of corrosion in virtually anhydrous organic solvents containing acids, which has hitherto attracted comparatively little attention, is investigated by means of a permanent immersion test at boiling temperature. The corrosion rate curves, as a function of time, and the phenomenology of the corrosion attack indicate a behaviour which differs from the corrosion phenomena encountered in the corresponding aqueous solutions in the following respects. The corrosion rate of iron, nickel and copper is higher in acidic ethanol solutions and in acetone with hydrochloric acid admixture, whilst the corrosion rate of nickel and copper is lower in acetic acid and sulphuric acid; in certain systems where acetone is used as a solvent, corrosion is prevented by the formation of protective layers. The reasons for these difference in behaviour are discussed.

Automated system for spectrophotometric detection of liquid phase hydrogen peroxide for concentrations up to 5% w/w

Abstract: An automated flow injection analysis system for H2O2 detection in the liquid phase, based on the photometric determination of the complex between hydrogen peroxide and a titanium (IV) reagent is presented. The system was tested for monitoring the H2O2 concentration in a lab-scale experimental setup for H2O2 direct synthesis. In its final configuration, the developed system allows a reliable and reproducible determination of H2O2 for a broad concentration interval between 1.02×10−3 mol l−1 and 1.16 mol l−1.

First time β-farnesene production by the versatile bacterium Cupriavidus necator.

Abstract: Terpenes are remarkably diverse natural structures, which can be formed via two different pathways leading to two common intermediates. Among those, sesquiterpenes represent a variety of industrially relevant products. One important industrially produced product is β-farnesene as a precursor for a jet fuel additive. So far, microbial terpene production has been mostly limited to known production hosts, which are only able to grow on heterotrophic substrates. In this paper, we for the first time describe β-farnesene production by the versatile bacterial host Cupriavidus necator on fructose, which is known to grow hetero- and autotrophically and even in bioelectrochemical systems. We were able to show a growth-dependent production of β-farnesene by expressing the β-farnesene synthase from Artemisia annua in C. necator H16 PHB-4. Additionally, we performed a scale-up in a parallel reactor system with production titers of 26.3 ± 1.3 µM β-farnesene with a fed-batch process. The β-farnesene production titers reported in this paper are not in the same range as titers published with known heterotrophic producers E. coli or S. cerevisiae. However, this proof-of-principle study with C. necator as production host opens new synthesis routes toward a sustainable economy and leaves room for further optimizations, which have been already performed with the known production strains.

Production of enclosed zeolite layers for use in e.g. catalysis or separation membranes, comprises first seed crystallization on carrier followed by further crystallization using different synthesis solution or gel

Abstract: Production of enclosed zeolite layers involves: (1) single-stage crystallization of zeolite seed crystals directly on a carrier; and (2) treating the seeded carrier with a synthesis solution or gel under suitable conditions to grow an enclosed layer in a second crystallization step, the synthesis solution or gel in this second crystallization cycle having a composition different to that in the seeding layer process.