Особенности синтеза сложных эфиров пентаэритрита и алифатических карбоновых кислот изомерного строения

Objectives. Due to their structures, pentaerythritol esters have a number of appealing properties such as high viscosity index when used as oils and excellent compatibility with polyvinyl chloride when used as plasticizers. For the production of pentaerythritol and carboxylic acids, natural gas can be used as a feedstock, which implies a strategic development of the petrochemical industry, a decrease in the amount of gas used for combustion, and its applications for the production of chemical products.Methods. The synthesis process was conducted in a self-catalysis mode with excess acids in a molar ratio of 8:1 and in the presence of a solvent (toluene) of ~30% per reaction mass. This ensures a uniform distillation of the reaction water at a constant temperature of 100–110 °C, a decrease in the side reaction products, and an increase in process selectivity. The products from the reaction mass were isolated by vacuum distillation, and identification of all the synthesized tetraesters was performed by chromatography–mass spectrometry analysis.Results. This work proposes options for optimizing the conditions of the thermal esterification of pentaerythritol with isomeric monocarboxylic acids (isobutyric, isovaleric, pivalic, and 2-ethylhexanoic acids) that have different reactivities due to their structures. Methods for isolating tetraesters of pentaerythritol and corresponding acids have been developed. The characteristics of the main series of ions of tetraesters of pentaerythritol and aliphatic isomeric acids C4–C8 in the mass spectra were obtained.Conclusions. The yields of tetraesters were at 95%–96% of the theoretical value, and product purity was >99.6%. The resulting target products (tetraesters) were characterized by relative color stability, where the maximum degree of color after cleaning was less than 20 units according to Hazen (180 units for tetra-2-ethylhexnoate), which corresponds to the standards in GOST 29131-91 (ISO 2211-73). The esterification rates were compared, and it was shown that the quantitative yields of isomeric tetraesters at 100–110 °C were achieved in 12–15 h for isobutyric and isovaleric acids, 25–27 h for 2-ethyl-hexanoic acid, and ~40 h for pivalic acid.  Цели. Сложные эфиры пентаэритрита за счет своей структуры обладают рядом привлекательных свойств: высоким индексом вязкости при их использовании в качестве масел и отличной совместимостью с поливинилхлоридными (ПВХ) полимерами при их использовании в качестве пластификаторов. При этом исходным сырьем для производства как пентаэритрита, так и карбоновых кислот может служить природный газ, что актуально с точки зрения снижения объемов газа, направляемого на сжигание, и его использование в производстве химической продукции. Цель работы – разработка новых методов синтеза тетраэфиров пентаэритрита и алифатических изомерных кислот С4–С8.Методы. Процесс проводили в режиме самокатализа при избытке кислоты в мольном соотношении 8:1, а также в присутствии растворителя (толуола) ~30% на реакционную массу, обеспечивающего равномерный отгон реакционной воды при постоянной температуре 100–110 °С, уменьшение продуктов побочных реакций и повышение селективности процесса. Продукты из реакционной массы выделяли методом вакуумной ректификации. Идентификация всех синтезированных тетраэфиров проведилась с использованием хроматомасс-спектрометрического анализа.Результаты. В работе предложены варианты оптимизации условий термической этерификации пентаэритрита изомерными монокарбоновыми кислотами (изомасляной, изовалериановой, пивалевой, 2-этилгексановой), обладающими за счет своей структуры различной реакционной способностью. Разработаны методики выделения тетраэфиров пентаэритрита и соответствующих кислот. Получены характеристики основных серий ионов тетраэфиров пентаэритрита и алифатических изомерных кислот С4–С8 в масс-спектрах.Выводы. В предложенных условиях проведения процесса выход тетраэфиров составил 95–96% от теоретического с чистотой не менее 99.6%. Полученные целевые продукты (тетраэфиры) характеризуются относительной цветостабильностью: максимальная степень окрашенности после очистки составляет не более 20 ед. по Хазену (для тетра-2-этилгексаноата – 180), что соответствует ГОСТ 29131-91 (ИСО 2211-73). Количественные выходы изомерных тетраэфиров при 100–110 °С достигаются: за 12–15 ч для изомасляной и изовалериановой кислоты, 25–27 ч для 2-этил-гексановой и ~40 ч для пивалевой кислоты

Assimilation of Temperatures and Column Dust Opacities Measured by ExoMars TGO-ACS-TIRVIM During the MY34 Global Dust Storm

Funding Information: ExoMars is a space mission of ESA and Roscosmos. The Atmospheric Chemistry Suite (ACS) experiment is led by IKI, the Space Research Institute in Moscow, Russia, assisted by LATMOS in France. This work, exploiting ACS/TIRVIM data, acknowledges funding by the CNES. The science operations of ACS are funded by Roscosmos and ESA. The ACS/TIRVIM team at IKI acknowledges the subsidy of the Ministry of Science and Higher Education of Russia. The authors acknowledge Sandrine Guerlet and the ACS/TGO team for supplying the data and the data center ESPRI/IPSL for their help in accessing the data. R. M. B. Young acknowledges funding from the UAE University grants G00003322 and G00003407. Supercomputing resources were provided by the UAE University High Performance Computing, with technical support from Anil Thomas and Asma Alneyadi, and at LMD by the IPSL mesocentre. The authors thank Luca Montabone for access to processed versions of Mars Climate Sounder temperature and dust observations, and Thomas Navarro and Claus Gebhardt for useful discussions.Peer reviewe

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described

An Investigation of Products of (n, ƒ), (n, ɣ) and (ɣ, ƒ), (ɣ, xn, p) Reactions on Samples of Uranium and Bismuth using the Phasotron and LINAС-200 Accelerators at JINR: Experiments and Calculations

The paper presents the results of physical experiments with 238U and 209Bi samples at the Nuclotron, Phasotron and LINAC-200 accelerators of the Joint Institute for Nuclear Research, with the results processed using the FLUKA, GEANT4 and MCNP programs

Цимолы. 1. Современное состояние процессов получения цимолов

The article analyzes methods for the preparation of cymenes based on using petrochemical raw materials: toluene and propylene/isopropanol. It is concluded that at present advanced technologies for the production of individual cymenes are absent, and the heterogeneous catalytic processes require significant improvement.Проанализированы методы получения цимолов, базирующиеся на использовании нефтехими-ческого сырья - толуола, пропилена/изопропилового спирта. Сделан вывод о том, что в настоящее время отсутствуют совершенные технологии получения индивидуальных цимолов, а гетерогенно-каталитические процессы требуют серьезной доработки

Цимолы. 2. Алкилирование толуола на сульфокатионите Amberlyst 36 dry

The possibilities of obtaining cymene by toluene alkylation with propylene on sulfocationite Amberlyst 36 Dry were estimated experimentally . The main characteristics of the process are given, and their analysis is presented.Экспериментально оценены возможности процесса получения цимолов алкилированием толуола пропиленом на сульфокатионите Amberlyst 36 Dry . Приведены основные характеристики процесса , дан их анализ

Transient HCl in the atmosphere of Mars

A major quest in Mars’ exploration has been the hunt for atmospheric gases, potentially unveiling ongoing activity of geophysical or biological origin. Here, we report the first detection of a halogen gas, HCl, which could, in theory, originate from contemporary volcanic degassing or chlorine released from gas-solid reactions. Our detections made at ~3.2 to 3.8 μm with the Atmospheric Chemistry Suite and confirmed with Nadir and Occultation for Mars Discovery instruments onboard the ExoMars Trace Gas Orbiter, reveal widely distributed HCl in the 1- to 4-ppbv range, 20 times greater than previously reported upper limits. HCl increased during the 2018 global dust storm and declined soon after its end, pointing to the exchange between the dust and the atmosphere. Understanding the origin and variability of HCl shall constitute a major advance in our appraisal of martian geo- and photochemistry

Wild boar density data generated by camera trapping in nineteen European areas

This report presents the results of field activities in relation to the generation of reliable wild boar density values by camera trapping (CT) in 19 areas in Europe, mainly in East Europe. Random Encounter Model (REM) densities ranged from 0.35±0.24 to 15.25±2.41 (SE) individuals/km2. No statistical differences in density among bioregions were found. The number of contacts was the component of the trapping rate that determined the coefficient of variation (CV) the most. The daily range (DR) significantly varied as a function of management; the higher values were detected in hunting grounds compared to protected areas, indicating that movement parameters are population specific, and confirming the potential role of hunting activities in increasing wild boar movement and contact rates among individual or groups. The results presented in this report illustrate that a harmonized approach to actual wildlife density estimation (namely for terrestrial mammals) is possible at a European scale, sharing the same protocols, collaboratively designing the study, processing, and analysing the data. This report adds reliable wild boar density values that have the potential to be used for wild boar abundance spatial modelling, both directly or to calibrate outputs of model based on abundance (such as hunting bags) or occurrence data. Future REM developments should focus on improving the precision of estimates (probably through increased survey effort). Next steps require an exhaustive and representative design of a monitoring network to estimate reliable trends of wild boar populations as a function of different factors in Europe. In this regard, the newly created European Observatory of Wildlife will be a network of observation points provided by collaborators from all European countries capable to monitor wildlife population at European level.EFSA-Q-2020-00677Peer reviewe

The Multi-Level Action of Fatty Acids on Adiponectin Production by Fat Cells

Current epidemics of diabetes mellitus is largely caused by wide spread obesity. The best-established connection between obesity and insulin resistance is the elevated and/or dysregulated levels of circulating free fatty acids that cause and aggravate insulin resistance, type 2 diabetes, cardiovascular disease and other hazardous metabolic conditions. Here, we investigated the effect of a major dietary saturated fatty acid, palmitate, on the insulin-sensitizing adipokine adiponectin produced by cultured adipocytes. We have found that palmitate rapidly inhibits transcription of the adiponectin gene and the release of adiponectin from adipocytes. Adiponectin gene expression is controlled primarily by PPARγ and C/EBPα. Using mouse embryonic fibroblasts from C/EBPα-null mice, we have determined that the latter transcription factor may not solely mediate the inhibitory effect of palmitate on adiponectin transcription leaving PPARγ as a likely target of palmitate. In agreement with this model, palmitate increases phosphorylation of PPARγ on Ser273, and substitution of PPARγ for the unphosphorylated mutant Ser273Ala blocks the effect of palmitate on adiponectin transcription. The inhibitory effect of palmitate on adiponectin gene expression requires its intracellular metabolism via the acyl-CoA synthetase 1-mediated pathway. In addition, we found that palmitate stimulates degradation of intracellular adiponectin by lysosomes, and the lysosomal inhibitor, chloroquine, suppressed the effect of palmitate on adiponectin release from adipocytes. We present evidence suggesting that the intracellular sorting receptor, sortilin, plays an important role in targeting of adiponectin to lysosomes. Thus, palmitate not only decreases adiponectin expression at the level of transcription but may also stimulate lysosomal degradation of newly synthesized adiponectin