Volume 90, Issue 11

Valentin Koptyug (1931–1997) was President of IUPAC during the 1987/89 biennium. In addition to his immense service to the educational, scientific and economic development of his own country Professor Koptyug made outstanding contributions to IUPAC over many years as well as to the other international organisations which he served. His interest in and dedication to the preservation of the environment and to the principles of sustainable development came very early. As a consequence, his influence has extended over many years. His inspiration has motivated IUPAC to greatly broaden the scope of its work and to collaborate with other international organisations to tackle real problems of societal interest.

The biochemical processes of synthesis and self-organization of the components of the lignin-carbohydrate matrix lead to the formation of a complex multi-component system considered as a nanobiocomposite, which is a thermodynamically limited ordered system of biopolymers in quasi -equilibrium. The concept of the thermodynamic state of the lignin–carbohydrate matrix and the possibility of regulating the areas of thermodynamic compatibility of components due to chemical and/or physical impact allow to consider the supercritical fluid technologies (SCFTs) as a tool for directing changes in the biocomposite’s structure and properties at the molecular level and also as a way of creating essentially new technologies for the complex processing of plant raw materials.

NiPd bimetallic systems were for the first time synthesized by laser electrodispersion (LED) of the Ni 77 Pd 23 alloy target followed by the deposition of produced bimetallic particles on a TEM copper grid and alumina granules. Selective area energy-dispersive analysis confirms the bimetallic nature of NiPd particles deposited on a TEM copper grid. Their mean size is 1.0 nm according to TEM. XPS data demonstrate that under deposition on alumina granules (total metal content of 0.005 wt.%), nickel in bimetallic particles nearly completely oxidizes to Ni 2+ species predominantly in the form of aluminate. At the same time major part of palladium (84%) exists in Pd 0 but oxidizes to Pd 2+ (80%) during 6 months storage in air. Both metals are deposited on the external surface of alumina granules and localized in the same areas. In situ reduction of both metals by H 2 in the catalytic cell of XPS spectrometer is hindered. Nickel is not reduced even at 450°C, confirming the formation of NiAlO x , whereas palladium is reduced at higher temperatures compared to a similar monometallic catalyst. Nevertheless, NiPd/Al 2 O 3 catalyst is more efficient in gas-phase chlorobenzene hydrodechlorination at 150–350°C than Ni/Al 2 O 3 and even Pd/Al 2 O 3 , and much more stable. The difference may be caused by the formation of new active sites due to the contact between Pd 0 and NiAlO x -modified support, and the protective action of spinel reacting with HCl by-product.

Quantitative determination of contaminants in environmental samples is usually hampered by low analyte recovery which results from the complex nature of the sample matrix. This study presents the application of a developed dispersive liquid–liquid microextraction method for the determination of 12 analytes in environmental samples including sea water, fresh water (lake, well and tap water), brackish water and soil samples. Matrix matched standards were used to compensate for the low analyte recovery recorded by the conventional calibration method. The effect of matrix dilution on analyte recovery was also tested. All matrix matched and matrix diluted spiked recoveries were done concurrently with calibration standards prepared in deionized water. Percent recoveries recorded for the analytes according to deionized water calibration standards ranged between 66 and 137%. Matrix matching and matrix dilution yielded close to 100% recovery results, but the later lowered the detection limit according to the dilution factor.

Herein, we report the synthesis, structural characterization and corrosion assay of a metal phosphonate – Mg(GLY)(H 2 O) 2 obtained from a tridentate ligand N,N-bis-phosphonomethylglycine (GLY) and a magnesium salt (MgSO 4 ·7H 2 O). The phosphonate was obtained by hydrothermal method at 80°C and also under ultrasounds conditions at 60°C. The FTIR, X-ray powder diffraction, elemental analysis and thermogravimetric analysis were performed in order to fully characterize the synthesized compounds and polarization experiments (CP) and electrochemical spectroscopy (EIS) to investigate the corrosion inhibition properties. The FTIR confirm the formation of magnesium phosphonate, and the X-ray diffraction showed the formation of a semi-crystalline compound. The elemental analysis confirmed the number of water molecules per formula unit of Mg(HO 3 PCH 2 ) 2 N(H)CH 2 COO·2H 2 O. The presence of nitrogen atom and phosphonate groups in the metal phosphonate structure anticipated that the presence of the small quantity of Mg(GLY)(H 2 O) 2 in saline solution will provide a positive effect on iron surface and act as a corrosion inhibitor. From the CP curves recorded in an aerated nitric saline solution, corrosion parameters (corrosion potential –Ecorr, corrosion density current – Jcorr, polarization resistance – Rp and corrosion rate – Rcorr) were extracted from Tafel plots. The decrease in Jcorr is associated with a shift in Ecorr to more negative values. These results suggest that metal phosphonate behaves as a mixed-type inhibitor, by reducing both the cathodic and anodic reactions. The optimum inhibitor concentration determined was 2 mM. At this concentration the corrosion rate decreases by 23% fold comparatively with iron in nitric acid solution without metal phosphonate. The EIS data in agreement with the polarization measurement resulted from polarization data.

From the view point of green chemistry, CO 2 utilization technologies with solar energy including the photoredox system have been received a lot of attention. As one of them, photoredox system containing a photosensitizer and a catalyst catalyzing a reaction of a carbon–carbon bond formation from CO 2 as a feed stock were constructed. In a recent study, we reported the visible light-induced malate (C4 compound) production from pyruvate (C3 compound) and CO 2 due to carbon–carbon bond formation with the system consisting an electron donor, a photosensitizer, diphenylviologen (PV 2+ ) derivative as an electron mediator in the presence of malic enzyme (ME). However, the interaction between a photosensitizer and PV 2+ derivative has not been clarified yet. In this study, water-soluble PV 2+ derivative, 1,1′-bis( p -sulfonatophenyl)-4,4′-bipyridinium salt (PSV 2+ ) was synthesized, and its electro-, photochemical properties were evaluated. Moreover, the photoredox properties of PSV 2+ with water-soluble Zn porphyrin were studied using fluorescence spectroscopy and steady state irradiation. The fluorescence of Zn porphyrin was quenched by PSV 2+ and the two-electron reduced form of PSV 2+ were produced with Zn porphyrin with steady state irradiation. In addition, reaction solution containing triethanolamine, tetraphenylporphyrin tetrasulfonate, pyruvate, ME, Mg 2+ and PSV 2+ in CO 2 saturated bis-tris buffer (pH 7.4) was irradiated with visible light, the oxaloacetate and malate were produced. This result indicates that PSV 2+ is an efficient electron mediator in the visible light-induced redox system for carbon–carbon bond formation with ME from CO 2 as a feedstock.

Chemical pollution is a problem of global importance. Substances of main concern of chemists worldwide are heavy metals. Heavy metals, such as copper (Cu), nickel (Ni), lead (Pb), vanadium (V), etc., can pose a serious hazard to the environment and human health. Heavy metals are toxic even at very low concentrations. The methodology, described in this paper, considers a migration of chemical pollutants in the environment, in conjunction with the approach used in the Russian regulatory system. Estimations of Maximum Available Concentration overrun show that calculated and experimental data agree to a good extent, particularly for mercury contamination in freshwater bodies. In this study, due to the necessity to obtain data on heavy metals content in water, soil and air, based on available data on emissions, it was decided to use the USEtox model for the simulation of the redistribution of chemicals among such environmental compartments as urban air and air of settlements, fresh waters and coastal sea waters, ocean, agricultural soils and other soils. The USEtox model was chosen because it is available in the free access and its structure can be modified if needed (the model is executed in MS Excel), in addition there is a positive experience in using this model in the combination with Geographic Information Systems (GIS). The algorithm of the calculation of the mass transfer coefficients of chemicals in the hydrosphere and atmosphere, with the use of GIS, is described. This algorithm will provide large amounts of data on the intermedia transfer and transportation of chemical substances with water and air flows and their accumulation in various environmental compartments on a global (the planet Earth) and regional scale for the high-resolution of 0.5°×0.5° grid. In this paper, the case study for the Leningrad Region (the Russian Federation) is presented.

The oligomer of acrylic acid with a thiooctadecyl end-group was obtained by using octadecyl mercaptan as the chain-transfer agent. The resulting oligomer was characterized by 1 H NMR and 13 C NMR spectroscopy and critical micelle concentration was determined in aqueous solution. The order with respect to the initiator concentration was 0.5 and 1.6 with respect to the monomer concentration. The abnormal reaction order with respect to the monomer concentration was explained by participation in the chain propagation of unassociated and associated forms of acrylic acid, which were stabilized by formation of hydrogen bonds. The kinetic parameters of telomerization were determined. Telomerization with acrylic acid in the non-associated form had lower activation energy and lower pre-exponential factor than in the case of associated forms. The synthesis of the acrylic acid oligomer with a thiooctadecyl end-group having a low critical micelle concentration in water was carried out in one stage and corresponds to the concept of atom economy.

The study is aimed at imparting dimensional stability and some functionalities to cellulosic aerogels. The polysaccharide suffers from mechanical strength loss in wetted state that restricts its application. Improvement is achieved by mean of microfibrillation of cellulosic fibers combining intense mechanical treatment with freeze-thawing. Addition of the latter decreases the number of cycles. Aerogels prepared from microfibrillated cellulose by freeze-drying hold their dimensional stability in solutions that makes possible treating them chemically without loss in shape. Here a method of directional sol-gel processing is applied to mineralize such aerogels by titania. Owing to covalent bonds to cellulose macromolecules formed via the condensation reactions, titania coating possesses good adhesion, not separating at heating when it is transferred in anatase form. Its photocatalytic activity results in self-cleaning of cellulose aerogels under outdoor sunlight irradiation. Calcination in air or carbonization in an inert gas atmosphere can serve to prepare metal oxide or composites with carbon of various shape and dimensionality.

Almost thirty years ago the criteria that are currently used to verify claims for the discovery of a new element were set down by the comprehensive work of a Transfermium Working Group, TWG, jointly established by IUPAC and IUPAP. The recent completion of the naming of the 118 elements in the first seven periods of the Periodic Table of the Elements was considered as an opportunity for a review of these criteria in the light of the experimental and theoretical advances in the field. In late 2016 the Unions decided to establish a new Joint Working Group, JWG, consisting of six members determined by the Unions. A first meeting of the JWG was in May 2017. One year later this report was finished. In a first part the works and conclusions of the TWG and the Joint Working Parties, JWP, deciding on the discovery of the now named elements are summarized. Possible experimental developments for production and identification of new elements beyond the presently known ones are estimated. Criteria and guidelines for establishing priority of discovery of these potential new elements are presented. Special emphasis is given to a description for the application of the criteria and the limits for their applicability.