A novel continuous homogeneous catalytic process for flourous biphasic systems

Homogeneous catalysts can provide very high activity and selectivity towards industrial desirable products at relatively mild conditions, but their commercialisation has been so far hampered by the problem of their separation from reaction mixture and solvent and hence the difficulties associated with their recycling. To overcome this problem a new concept of fluorous biphasic homogeneous catalysis has been developed to facilitate the separation and recycling of the catalyst. In these systems the catalyst is dissolved in a fluorous solvent. Under ambient conditions the fluorous phase is immiscible with the organic one containing the reaction components, facilitating catalyst separation and recycling. At reaction conditions only one phase is formed allowing excellent contact between substrate and catalyst and eliminating mass transfer limitation. This is a generic technology with high potential for industrialisation that is applicable to a wide variety of homogeneous catalytic systems. In this work a continuous reaction system is developed, which includes a chemical reactor that is connected via a heat exchanger with a gravity settler, where from the catalyst phase is continuously recycled to the reactor. The work is focused on the hydroformylation of higher alkenes, a reaction system of great industrial importance. The liquid - liquid equilibrium of the fluorous solvent - organic phase was studied. A proof of concept separation study in a continuous system was also carried out demonstrating the efficiency of the separation of the two phases. Finally, reaction studies were carried out in the presence of a fluorous modified rhodium catalyst. Conversion levels up to 70% were observed, with linear to branched product ratios being around 12, while the fluorous catalyst was successfully recycled to the reactor. Efficient stirring was essential for high conversions for minimising alkene isomerisation. Leaching of the ligand, rhodium and the fluorous solvent into the organic product phase was significant

Functioning principles of the internal quality assurance system of educational services

With ever increasing demands of a labor market for specialists the important role played revision of approaches to quality of education. In accordance with the European standards and guidelines on quality of higher education (ESG) a new paradigm of higher education is student centered approach to learning, teaching and assessment of results. Aim: The aim of research is to determine the principles of the internal system of quality assurance of educational services in higher education institutions. Materials and Methods: Each educational institution according to the context of its activity has to independently manage the principles of operation, their justification and degrees of importance. The authors proposed and described the cycle model of strategic management of universities in order to achieve sustainable development. Results: In this paper the authors presented the proposals on policy, mission and objectives of the higher education institution in the field of quality in order to implement student centered teaching. It is shown that the definition of the principles of the internal system of quality assurance operation of educational services in higher education institutions is a strategically important decision that will improve their work and allow them to initiate and manage sustainable development

Performance of octene in fluorous biphasic hydroformylation: octene distribution and reversible transfer between perfluoromethylcyclohexane and nonanal

During fluorous biphasic hydroformylation 1-octene is transferred from the fluorous into the organic product phase and then from the product layer back to the fluorous layer again, due to the immiscibility of nonanal with PFMCH. The effect of the temperature and the total amount of octene on the above behaviour were also studied. (C) 2003 Elsevier B.V. All rights reserved.</p

Separation studies in a continuous flow fluorous biphasic system - Proof of concept

A proof of concept study was undertaken for the separation of the fluorous solvent from the organic reactants/products of a fluorous biphasic system, in the absence of fluorous modified Rh catalyst. Fast and efficient separation of the two phases was observed. The more polar products were present in the organic phase-i.e. the higher the simulated conversion level-the less was the leaching of the fluorous solvent in the organic phase. (C) 2004 Elsevier B.V. All rights reserved

The design of a continuous reactor for fluorous biphasic reactions under pressure and its use in alkene hydroformylation

A reactor, into which all reagents can be fed continuously and from which the reaction mixture can be continuously removed to a gravity separator, where product can be continuously removed and the catalyst phase recycled to the reactor, has been constructed and used for the hydroformylation of alkenes in fluorocarbon solvents.</p

For the experimental determination of the parameters of free oscillations

Вимірювальний стенд для експериментального визначення параметрів вільних коливань. Розглянуто важливість вимірювання вільних коливань лезового інструменту для досягнення цілей удосконалення як інструменту так і процесу різання. Доведена доцільність використання безконтактного вимірювання взаємного положення інструменту та деталі. Розроблено принципову схему вимірювальної системи для вимірювань що базується на первинних перетворювачах, що використовують ефект Холу. Наведено налаштування вимірювальної системи, порядок її тарування та порядок оброблення вимірювальної інформації. Наведена математична модель вільних коливань інструменту та наведені графіки з експериментального дослідження цих коливань. Зроблено висновки щодо збіжності результатів вимірювань та моделювання.Измерение свободных колебаний лезвийного инструмента является важной задачей для достижения целей усовершенствования, как инструмента, так и процесса резания. Доказана целесообразность использования бесконтактного измерения взаимного положения инструмента и детали. Разработана принципиальная схема измерительной системы для измерений основанный на первичных преобразователях использующих эффект Холла. Приведены настройки измерительной системы, порядок ее тарирования и порядок обработки измерительной информации. Приведена математическая модель свободных колебаний инструмента и графики экспериментального исследования этих колебаний. Сделаны выводы по сходимости результатов измерений и моделирования.Consider the importance of measuring free and forced vibrations edge cutting tool to achieve the objectives of improvement as a tool and cutting process. Proved the feasibility of using non-contact measurement of the relative position of tools and parts. Developed schematic diagram measuring system for measurements based on primary converters using Hall effect. Shows the settings of the measuring system, the procedure of calibration and measurement data processing procedure. The mathematical model of free oscillations tool, and shows graphs of the experimental study of these oscillations. The conclusions about convergence measurement results and modeling

A continuous process concept for homogeneous catalysis in fluorous biphasic systems

A novel continuous homogeneous catalytic system for the long-term testing of hydroformylation in fluorous biphasic systems has been developed. Conversion levels up to 70 % were observed, with linear to branched product ratios being around 12, while the fluorous catalyst was successfully recycled to the reactor. Efficient stirring is essential for high conversions for minimising alkene isomerisation. Leaching of the ligand, rhodium and the fluorous solvent into the organic product phase are significant. (C) 2004 Elsevier Ltd. All rights reserved