István Gács

The Effect of HCl on the Copper(II) Chloride/Pyridine/Water System: Synthesis, Properties and Crystal Structure of [(pyH)2CuCl4] and [(pyH)2Cu3Cl8(H2O)2]n

Bis(pyridinium) tetrachlorocuprate monomer 1 and bis(pyridinium) octachlorodiaquatricuprate polymer 2 were synthesized and their crystal structures were determined. Both complexes contain pyridinium cations with bifurcated H-bridges. These H-bridges stabilize the monomeric structure of the tetrachlorocuprate anion together with the steric demand of the relatively large pyridinium ions in the crystal lattice of 1. Conversely, at the lower pyridinium ion:copper(II) ratio of 2, the bifurcated hydrogen bonds reduce the electron density on the chloride ions in such a way that the electron repulsion decreases and coordination spheres with more ligand interactions develop. Obviously, water may be a successful competitor for ligand sites in 2 as well. The octahedral and square-pyramidal structural units condense into polymeric chains which are stabilized by the interchain hydrogen bond networks of the water molecules. The structure motif of SP-5-[OC-6-SP-5-SP-5]-OC-6 (−CuCl5-[CuCl4(OH2)2-CuCl5CuCl5]-CuCl4(OH2)2-) were observed in 2, and the two neighboring square-pyramidal units were found to be localized in a transoid position. The IR and ESR spectroscopical characterization of complexes was also performed.

Three Reagents in One: Ammonium Permanganate in the Oxidation of Benzyl Alcohol

The oxidation or consecutive ammoxidation reaction of benzyl alcohol with solid ammonium permanganate was studied. The first oxidation step leads to the formation of benzaldehyde, ammonia, and MnO2. The MnO2 is present in the system in a colloidal form which facilitates the reaction between aldehyde and ammonia, and this latter reaction then yields benzonitrile. All these products are formed in a heterogeneous system under relatively mild conditions. The yield of benzaldehyde has an optimum at room temperature and increases with increasing reaction time. At higher temperature (e.g. 80 °C) benzonitrile is formed together with minor amounts of benzyl benzoate

Automatic sample preparation of35S labelled organic compounds for liquid scintillation counting

An automatic sample preparation method for the determination of35S in organic compounds by liquid scintillation counting is described. The sample is burned in a stream of oxygen and the combustion products are led onto a quartz wool column wetted with dilute hydrogen peroxide. Sulfur oxides are retained on the quartz wool as sulfuric acid, while the other acid producing combustion products are eliminated by evaporation. The residual sulfuric acid in rinsed with distilled water, the sulfuric acid solution obtained is added to a liquid scintillation cocktail and the radioactivity is measured with a liquid scintillation counter. The combustion-evaporation process runs automatically according to the operational program carried out by an electronic programmer.

A new automatic combustion method for the liquid scintillation assay of tritium and carbon-14 in singly or doubly labelled organic materials

An automatic, rapid combustion method has been developed for the determination of tritium and14C in singly or doubly labelled organic materials by liquid scintillation counting. The sample is burned in a stream of oxygen. The water formed and its tritium content are retained from the gas stream in an absorber containing a small amount of diethyleneglycol monoethyl ether. Radioactive carbon dioxide, if included in the combustion products, is transferred into 3-methoxypropylamine. The final solutions ready for counting are obtained in less than three minutes. Quantitative collection recoveries for both tritium and14C are achieved and no cross-contamination occurs.

Simultaneous determination of35S and14C in double-labelled organic compounds by liquid scintillation counting

An isotope analytical method for the simultaneous determination of35S and14C in double-labelled organic compounds by liquid scintillation counting is described. The sample is burned in a stream of oxygen. Sulfur oxides are converted to sulfuric acid and separated from other combustion products, including carbon-14 dioxide, on a heated quartz wool column previously wetted with hydrogen peroxide. Carbon dioxide is collected from the gas stream by an absorbent suitable for liquid scintillation counting. The residual sulfuric acid is rinsed off the column with water and the aqueous solution obtained is mixed with a liquid scintillation cocktail for radioactivity measurement. The final solutions ready for counting are obtained in less than fifteen minutes, quantitative collection recovery is achieved and no cross contamination occurs.

An Integrated Waste-Free Biomass Utilization System for an Increased Productivity of Biofuel and Bioenergy

The increase in production and utilization of biomass and other renewable sources of energy are important challenges of the energy industry. It generates, however, demands for ecologically and economically acceptable production systems. Here we report an integrated system of known and new technologies developed for biomass conversion to biofuels. This includes classical and biobutanol based new biodiesels, biogas and electricity production, and an agricultural production system involving fertilization with the ash of the biomass power plants. Basically, three types of agricultural production system are needed for the agricultural segment of the integrated system, namely: A – plants for combustion in biomass power plants (energy grass) B – plants for production of vegetable oils for biodiesel production C – plants for conversion of sugar derivatives to price alcohols, mainly butanol as a diesel fuel source Depending on the climate, the soil type, the agricultural experiences, and the type of the plants (A,B,C), the produced biomass materials can fulfill more than one requirement as it can be seen in Fig. 1. Depending on the constituents of the biomass (cellulose, starch, lignin, oil, proteins), the energy production can be performed via direct combustion or, after digestion in biogas systems, by using the biogas. The biomass power plants, biogas combustion plants/engines produce hot water, steam and electricity. In plants type B soybean, rape, sunflower or likes are pressed to obtain the oil, while the pressing cake can be used as optimal raw material for biogas plants due to its high protein content, while the

Quasi-intramolecular acid-base reactions in aqueous solutions of metal-complexes of basic ligands. I. Generalized theoretical considerations on the deammoniation of [MLm]Xn type ammonia complexes

The theoretical investigation on the distribution of chemical species obtainable as a function of the temperature of the aqueous solutions of metal complexes containing a basic ligand, altogether with the solubility relationship of the compounds to be formed, offers a simple means of planning the preparation of various types of complexes, double and single salts of the central metal cation and onium type compounds of protonated ligand of the central ion and the anion.

Automatic isotope gas analysis of tritium labelled organic materials

An isotope analytical procedure and an automatic instrument developed for the determination of tritium in organic compounds and biological materials by internal gas counting are described. The sample is burnt in a stream of oxygen and the combustion products including water vapour carrying the tritium are led onto a column of molecular sieve-5A heated to 550 °C. Tritium is retained temporarily on the column, then transferred into a stream of hydrogen by isotope exchange. After addition of butane, the tritiated hydrogen is led into an internal detector and enclosed there for radioactivity measurement. The procedure, providing quantitative recovery, is completed in five minutes. It is free of memory effect and suitable for the determination of tritium in a wide range of organic compounds and samples of biological origin.

A new decomposition technique for the determination of sulphur or sulphur-35 in organic compounds as sulphuric acid

SummaryA combustion procedure is presented, in which the sulphur-containing sample is burnt in a stream of oxygen and the combustion products are led onto a small heated quartz wool column wetted with dilute hydrogen peroxide. Sulphur oxides are retained as sulphuric acid on the quartz wool, while the other combustion products are completely eliminated by evaporation. The residual sulphuric acid is rinsed off with a few ml of distilled water, then titrated with standard alkali. In the case of organic compounds labelled with sulphur-35 the sulphuric acid solution is added to a liquid scintillation cocktail for radioactivity measurement. The combustion-evaporation process takes 15 min, and provides an analytical reproducibility better than 0.3% for sulphur and 0.5% for sulphur-35.ZusammenfassungEin Analysenvorgang für schwefelhältige Proben wurde angegeben, wobei diese im Sauerstoffstrom verbrannt und die Verbrennungsprodukte über Quarzwolle geleitet werden, die mit verdünntem Wasserstoffperoxid befeuchtet ist. Schwefeloxide werden dabei als Schwefelsäure zurückgehalten, während die anderen Verbrennungsprodukte durch Abdampfen völlig entfernt werden. Die Schwefelsäure wird mit wenigen Milliliter dest. Wasser ausgewaschen und alkalimetrisch titriert. Im Fall organischer Substanzen, die mit35S markiert sind, wird die Schwefelsäure der Radioaktivitätsmessung zugeführt. Der Verbrennungs- bzw. Verdampfungsvorgang dauert 15 min und gewährleistet eine analytische Reproduzierbarkeit von <0,3% für Schwefel bzw. <0,5% für35S.

A semi-automatic combustion method for the simultaneous determination of3H and35S in doubly labelled organic materials by liquid scintillation counting

A sample preparation method developed for the simultaneous liquid scintillation assay of tritium and35S in doubly labelled organic materials is described. The sample is burnt in a stream of oxygen and the radioactive isotope carriers formed are collected separately for individual counting.35S content of the sample is measured as a dilute sulfuric acid solution, while the tritium is counted as water. The procedure is free of cross-contamination and memory effect, provides quantitative analytical recovery, and the final solutions ready for counting are obtained in twelve minutes.