A Fully Integrated Continuous-Flow System for Asymmetric Catalysis: Enantioselective Hydrogenation with Supported Ionic Liquid Phase Catalysts Using Supercritical CO₂ as the Mobile Phase

A continuous-flow process based on a chiral transition-metal complex in a supported ionic liquid phase (SILP) with supercritical carbon dioxide (scCO2) as the mobile phase is presented for asymmetric catalytic transformations of low-volatility organic substrates at mild reaction temperatures. Enantioselectivity of >99 % ee and quantitative conversion were achieved in the hydrogenation of dimethylitaconate for up to 30 h, reaching turnover numbers beyond 100 000 for the chiral QUINAPHOS–rhodium complex. By using an automated high-pressure continuous-flow setup, the product was isolated in analytically pure form without the use of any organic co-solvent and with no detectable catalyst leaching. Phase-behaviour studies and high-pressure NMR spectroscopy assisted the localisation of optimum process parameters by quantification of substrate partitioning between the IL and scCO2. Fundamental insight into the molecular interactions of the metal complex, ionic liquid and the surface of the support in working SILP catalyst materials was gained by means of systematic variations, spectroscopic studies and labelling experiments. In concert, the obtained results provided a rationale for avoiding progressive long-term deactivation. The optimised system reached stable selectivities and productivities that correspond to 0.7 kg L−1 h−1 space–time yield and at least 100 kg product per gram of rhodium, thus making such processes attractive for larger-scale application

Continuous-Flow Asymmetric Hydrogenation of the β-Keto Ester Methyl Propionylacetate in Ionic Liquid–Supercritical Carbon Dioxide Biphasic Systems

A continuous-flow process for the asymmetric hydrogenation of methyl propionylacetate as a prototypical β-keto ester in a biphasic system of ionic liquid and supercritical carbon dioxide (scCO2) is presented. An established ruthenium/2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) catalyst was immobilised in an imidazolium-based ionic liquid while scCO2 was used as mobile phase transporting reactants in and products out of the reactor. The use of acidic additives led to significantly higher reaction rates and enhanced catalyst stability albeit at slightly reduced enantioselectivity. High single pass conversions (>90%) and good enantioselectivity (80–82% ee) were achieved in the first 80 h. The initial catalyst activity was retained to 91% after 100 h and to 69% after 150 h time-on-stream, whereas the enantioselectivity remained practically constant during the entire process. A total turnover number of ∼21,000 and an averaged space-time yield (STYav) of 149 g L−1 h−1 were reached in a long-term experiment. No ruthenium and phosphorus contaminants could be detected via inductively coupled plasma optical emission spectrometry (ICP-OES) in the product stream and almost quantitative retention by the analysis of the stationary phase was confirmed. A comparison between batch-wise and continuous-flow operation on the basis of these data is provided

Повышение эффективности эксплуатации скважин, оборудованных установками электроцентробежных насосов на месторождениях Западной Сибири

Поиск способов оптимизации работы скважин, оборудованных установками электроцентробежных насосов, на месторождениях Западной Сибири.Больше 80% скважин Западной Сибири оборудованы установками электроцентробежных насосов. Многие из них эксплуатируются длительное время и находятся на поздних стадиях разработки, что осложняет процесс добычи нефти. Повышение эффективности эксплуатации скважин оборудованных установками электроцентробежных насосов потенциально позволит повысить эффективность более чем 80% месторождений.Search for ways to optimize the operation of wells equipped with electric centrifugal pump installations in the fields of Western Siberia. More than 80% of the wells in Western Siberia are equipped with electric centrifugal pump installations. Many of them are operated for a long time and are in the late stages of development, which complicates the process of oil production. Improving the operational efficiency of wells equipped with electric centrifugal pump installations will potentially increase the efficiency of more than 80% of fields

Разработка мероприятий по оздоровлению финансового состояния ООО «Металлист»

Цель бакалаврской работы – проведение анализа финансово-экономических показателей деятельности предприятия и разработка рекомендаций по улучшению его финансового состояния.The purpose of the bachelor's work is to analyze the financial and economic performance of the enterprise and develop recommendations to improve its financial condition

Continuous-Flow Asymmetric Hydrogenation of an Enol Ester by using Supercritical Carbon Dioxide: Ionic Liquids versus Supported Ionic Liquids as the Catalyst Matrix

The continuous-flow Rh-catalyzed asymmetric hydrogenation of the enol ester 1-(trifluoromethyl)vinyl acetate was investigated by using supercritical carbon dioxide (scCO2) as the mobile phase and either ionic liquids (IL) or supported ionic liquids (SILP) as the catalyst matrix. Three molecular catalysts based on chiral ligands were evaluated. The catalyst based on the phosphine-phosphoramidite ligand (Sa,Rc)-Xyl-QUINAPHOS in combination with the SILP/scCO2 immobilization strategy provided the most effective system under continuous-flow conditions and gave a remarkably stable performance. During 233 h on stream, high single-pass conversions (90–70 %), slightly increased enantioselectivity (80–84 % ee), and a turnover number of 70 400 were observed; this turnover number shows a six-fold increase over that achieved in the IL/scCO2 system with the same catalyst