Chemical Papers

http://link.springer.com/journal/11696

List of Papers (Total 44)

Effect of medium pH on chemical selectivity of oxalic acid biosynthesis by Aspergillus niger W78C in submerged batch cultures with sucrose as a carbon source

The pH of the medium is the key environmental parameter of chemical selectivity of oxalic acid biosynthesis by Aspergillus niger. The activity of the enzyme oxaloacetate hydrolase, which is responsible for decomposition of oxaloacetate to oxalate and acetate inside the cell of the fungus, is highest at pH 6. In the present study, the influence of pH in the range of 3–7 on oxalic ...

Continuous laccase concentration in an aqueous two-phase system

An approach to describe continuous partitioning of Cerrena unicolor laccase in a PEG 6000—phosphate aqueous two-phase system was proposed. The laccase was separated from crude supernatant of C. unicolor-submerged culture, and all the experiments were carried out in 25 °C and pH 7 conditions. Masses of both phases and their compositions at phase equilibrium, as well as laccase ...

Comparative PIV and LDA studies of Newtonian and non-Newtonian flows in an agitated tank

The paper presents results of an experimental study of the fluid velocity field in a stirred tank equipped with a Prochem Maxflo T (PMT) type impeller which was rotating at a constant frequency of N = 4.1 or 8.2 s−1 inducing transitional (Re = 499 or 1307) or turbulent (Re = 2.43 × 104) flow of the fluid. The experiments were performed for a Newtonian fluid (water) and a ...

Radiodegradation of nadolol in the solid state and identification of its radiolysis products by UHPLC–MS method

Nadolol ((2R*,3S*)-5-{[(2R*)-3-(tert-butylamino)-2-hydroxypropyl]oxy}-1,2,3,4 tetrahydronaphthalene-2,3-diol) in substantia was exposed to ionizing radiation generated by a beam of high-energy electrons in an accelerator, in the standard sterilisation dose of 25 kGy and in higher doses of 50 − 400 kGy. The irradiated and non-irradiated (control) samples were analysed by the ...

Facilitated transport of palladium(II) across polymer inclusion membrane with ammonium ionic liquid as effective carrier

This work focuses on the application of polymer inclusion membrane (PIM) with tricaprylmethylammonium thiosalicylate, [A336][TS] (TOMATS), a thiol-containing task-specific ionic liquid for the transport of Pd(II) ions from aqueous solutions. 0.3 M thiourea in 0.1 M hydrochloric acid was found the most effective stripping phase in the transport of Pd(II) from membrane phase ...

The long-term studies of osmotic membrane distillation

The results of osmotic membrane distillation carried out for 2.5 years were presented in this work. The influence of the process conditions, such as temperature and brine concentration on the permeate flux, was investigated. The saturated NaCl solutions and distilled water were used as a stripping solution and feed, respectively. A continuous regeneration of stripping solution was ...

A simple economic and heat transfer analysis of the nanoparticles use

In this paper, a review of the impact of most common nanoparticles on the Leidenfrost temperature T Leid in heat transfer applications is delivered. Moreover, a simple economic analysis of the nanoparticles use is proposed. When coolant is distilled water, T Leid can range 150–220 °C; occasionally, it can even amount to over 400 °C. When the base liquid is modified by additives, ...

Degradability of cross-linked polyurethanes based on synthetic polyhydroxybutyrate and modified with polylactide

In many areas of application of conventional non-degradable cross-linked polyurethanes (PUR), there is a need for their degradation under the influence of specific environmental factors. It is practiced by incorporation of sensitive to degradation compounds (usually of natural origin) into the polyurethane structure, or by mixing them with polyurethanes. Cross-linked polyurethanes ...

SCRAMBLE’N’GAMBLE: a tool for fast and facile generation of random data for statistical evaluation of QSAR models

A common practice in modern QSAR modelling is to derive models by variable selection methods working on large descriptor pools. As pointed out previously, this is intrinsically burdened with the risk of finding random correlations. Therefore it is desirable to perform tests showing the performance of models built on random data. In this contribution, we introduce a simple and ...

Manganese(II) complexes with Bn-tpen as powerful catalysts of cyclohexene oxidation

Manganese(II) complex [(Bn-tpen)MnII]2+ activated dioxygen for oxidation of cyclohexene in acetonitrile (MeCN) and methanol (MeOH). In MeCN, ketone (2-cyclohexen-1-one), alcohol (2-cyclohexen-1-ol) and small amounts of epoxide (cyclohexene oxide) were produced in this reaction, while in MeOH only ketone was formed. In the most efficient experiment, the combination of 2.5 × 10−4 ...

A new model of cavern diameter based on a validated CFD study on stirring of a highly shear-thinning fluid

Results of numerical simulations of momentum transfer for a highly shear-thinning fluid (0.2% Carbopol) in a stirred tank equipped with a Prochem Maxflo T type impeller are presented. The simulation results were validated using LDA data and both tangential and axial force measurements in the laminar and early transitional flow range. A good agreement between the predicted and ...

Phosphonium ionic liquids as extractants for recovery of ruthenium(III) from acidic aqueous solutions

The aim of this work is to investigate extraction of ruthenium(III) from acidic aqueous solutions with phosphonium ionic liquids such as trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101), trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate (Cyphos IL 104) and tributyl(tetradecyl)phosphonium chloride (Cyphos IL 167) as extractants. The influence of HCl ...

New thermoplastic poly(carbonate-urethane)s based on chain extenders with sulfur atoms

New thermoplastic segmented polyurethanes were obtained by a one-step melt polyaddition using 40, 50 and 60 mol% poly(hexane-1,6-diyl carbonate) diol of \(\bar{M}_{n} = 860\) g mol−1, 1,1′-methanediylbis(4-isocyanatobenzene) and 2,2′-[sulfanediylbis(benzene-1,4-diyloxy)]diethanol, 2,2′-[oxybis(benzene-1,4-diylsulfanediyl)]diethanol or ...

Valorisation to biogas of macroalgal waste streams: a circular approach to bioproducts and bioenergy in Ireland

Seaweeds (macroalgae) have been recently attracting more and more interest as a third generation feedstock for bioenergy and biofuels. However, several barriers impede the deployment of competitive seaweed-based energy. The high cost associated to seaweed farming and harvesting, as well as their seasonal availability and biochemical composition currently make macroalgae ...

Determination of mycotoxins, alkaloids, phytochemicals, antioxidants and cytotoxicity in Asiatic ginseng (Ashwagandha, Dong quai, Panax ginseng)

Mycotoxins and selected hazardous alkaloids in the medicinal plants (Panax ginseng, Angelica sinensis, and Withania somnifera) and dietary supplements were determined. Purine alkaloids were found in majority of samples; however, isoquinoline alkaloids were less abundant than indole. The predominant alkaloids appear to be caffeine (purine group), harman (indole group) and berberine ...

Quantitative analysis of amphiphilic N-alkyloxypyridinecarboximidamide by liquid chromatography–tandem mass spectrometry

LC–MS/MS method to determine hydrophobic N-alkyloxy substituted amidines: N-(2-ethylhexyloxy)pyridine-2-carboximidamide, N-(2-ethylhexyloxy)pyridine-3-carboximidamide, N-(2-ethylhexyloxy)pyridine-4-carboximidamide, N-decyloxy pyridine-2-carboximidamide, N-decyloxypyridine-3-carboximidamide and N-decyloxypyridine-4-carboximidamide was developed and validated in terms of linearity, ...