Determination of the Composition of Commercial Tannin Extracts by Liquid Secondary Ion Mass Spectrometry (LSIMS)

The composition of various commercial tannin extracts were determined by liquid secondary ion mass spectrometry (LSIMS). Spectra were obtained directly from tannin extracts without any pre-separation. Eight different tannin powders were analysed: three gallotannins (Chinese, Turkish, tara), three ellagitannins (sweet chestnut, pendunculata oak, sessile oak), one mixed hydrolysable tannin (myrabolans) and one proanthocyanidin (grape seeds). This method enabled the main molecules in these powders to be identified.     

Progress in the Enzymatic Saccharification of Wheat Starch

Problems were noticed when trying to include wheat starch to the normal liquefaction and saccharification lines because of the formation of precipitations which are difficult to filter. The effects of different side activities of Aspergillus niger glucoamylases on the filterability of wheat syrups are demonstrated. In order to speed up filtration, viscosity has to be decreased by degradation of arabinoxylanes with present pentosanes. A new enzyme has been discovered which is able to split partially the lysophospholipids contained in wheat starch and let the insoluble components flocculate to big particles. This enzyme splits the phospholipids into free fatty acids and glycerophophorylcholines. The properties of this enzyme present in a novel glucoamylase preparation for the wheat starch processing are demonstrated by using an HPLC method, showing the degradation of wheat lipids as well as synthetic lysophopholipids.     

Automatisierte enzymatische Bestimmung von Glucose,Maltose und Stärke auf Mikrotiterplatten

Automated Enzymatic Determination of Glucose, Maltose and Starch on Microtiter Plates. An automated enzymatic method for the determination of sugars and starch is described. The elimination of inherent methodical errors in the optical measurement of microtiter plates and the evalution of 96 raw data is done with the “LBR1993” software. Analysis is based on a 10min hydrolysis by glucoamylase at room temperature and determination of glucose with the GOD-PAP-method. A recovery of greater 99% for maize and potato starch is possible if the starch is transformed at 100°C by α-amylase to α-dextrins and converted in a second step with 8.88 g glucoamylase/g substrate to glucose. Solubilization of potato starch in 1 N sodium hydroxide at room temperature gives a recovery of 93%. Heating (60°C) in 0.5 N sodium hydroxide (AFNOR-method) is not suitable for sugar analysis and certain kinds of starch.     

Zur Existenzfähigkeit von 2-Imino-2H-1,3-thiazinen

On the Existence of 2-Imino-2H-1,3-thiazines The title compounds 2 are readily liberated from the 2-amino-1,3-thiazinium salts 1 by treatment with bases. Their stability depends sensitively on the substituents at the imino-N. The imino-N substituted 2a – i are isolable as well-defined coloured substances. Reaction of the 2 as well 1 with nucleophilic agents affords pyrimidine-2-thiones ( 4 , 9 – 11 , 16 – 18 ). In these ring transformations a nucleophilic addition at ring position 6 as primary reaction step is preferred. The imino-N unsubstituted representatives display a more complicated behaviour; the highly enhanced reactivity prevents or handicaps, respectively, any isolation. As exemplified in the base-induced ring-transformation of 1 m to the pyrimidine derivative 19 , these 2 are able to react as nucleophiles too, and versatile intermolecular self-reactions are increasingly favoured.     

Zur Darstellung und Charakterisierung von Vinylsenfölen

Synthesis and Characterisation of Vinylisothiocyanates The preparation of vinylisothiocyanates by treatment of γ-chloroallylchlorides with KSCN followed by rearrangement of the γ-chloroallylthiocyanates is described. The structure is proved by the reaction of the vinylisothiocyanates with mercaptides and by spectroscopic methods.     

Reaktionen mit N-Acylimino-dithiokohlensäurediestern

Reactions with N-Acylimino-dithiocarbonic-acid-diesters . Reactions of N-acylimino-dithiocarbonic-acid-S,S-diesters 1 with nucleophilic com-pounds present new possibilities to synthesize heterocycles. With amines 1a reacts by mono- and disubstitution, respectively, of methylthio-groups to isothioureas 2 and guanidines 3 , with 1,2-bi-nucleophilic arenes to benzoheterocycles 4 , with aliphatic diamines to imidazolidines 5 , pyrimidines 6 , diazepines 7 and the hexamethylene-diamine-derivatives 8. 1a reacts also with hydrazines to 1,2,4-triazoles 9 and with hydrazides to the thiosemicarbazones 10 or 1,3,4-oxadiazoles 11 . Heterocyclisations of 1 with guanidines, thiourea, salts of thiourea and amidines give the 1,3,5-triazines 12, 14, 15 and 16 . N-benzoyl-dithiocarbonic-acid-methylester -amid reacts with CH-acidic compounds to thiazoles 17 . The structures of the final products are determined by i.r.-, ¹H-n.m.r.-, u.v.- and mass-spectras.     

Three‐dimensional modeling of porosity development during the gasification of a char particle

This work is devoted to the three‐dimensional, direct modeling of porosity and specific surface development during the gasification of a char particle. The model was developed for heterogeneous reactions occurring inside a char particle in a kinetically controlled regime. The main goal of this work is to analyze the impact of different pore size distributions on the particle carbon conversion rate. In particular, it is shown that under certain conditions the outer particle surface can influence the specific surface area. In this context the possible adaptation of the parameter ψ from the random pore model (RPM) developed by Bhatia and Perlmutter is explained. The results of simulations are compared against the RPM and discussed. Additionally, based on the results of simulations, the physics behind several input parameters used by the RPM are explored. Finally, the possible fragmentation of a chemically reacting char particle during its gasification in dependence of instantaneous porosity was investigated numerically. It was shown that the earliest fragmentation occurs at a carbon conversion of about 0.5–0.6 due to the disaggregation of the pore walls. The results are discussed and compared implicitly with data published in the literature. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1638–1647, 2017