Wyniki wyszukiwania - BazTech

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Zastosowanie zielonych rozpuszczalników w syntezie nienasyconych związków boro- i krzemoorganicznych na drodze reakcji hydrometalacji i sprzęgania Marcińca

Walkowiak Jędrzej

Wiadomości Chemiczne

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2021

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[Z] 75, 1-2

111--136

EN

Unsaturated organoboron and organosilicon compounds constitute an important class of organometallic compounds, which due to the presence of silyl- or boryl- group attached to Csp2 atoms, their simple and straightforward transformations in coupling and demetallation reactions, found a broad range of applications in the synthesis of fine chemicals or new materials with tailored properties. Such compounds might be synthesized in many transformations but two of them: hydrometallation and Marciniec coupling reactions permitted to obtain compounds with high effectivity, selectivity, and in the case of hydrometallation reactions with excellent atom economy. Most of these processes occur in a homogeneous phase, which ensures excellent yields and stereo- and regioselectivity. On the other hand, such conditions generate problems with catalyst reuse, product separation, and substantial consumption of toxic, volatile organic solvents. According to the assumptions of sustainable development in chemistry, the new procedures, which allow to intensify the process in terms of its efficiency, according to green chemistry rules are of prior importance in modern chemical industry. In this manuscript, the newest achievements in the application of green solvents (ionic liquids, liquid polymers, and supercritical CO2) in catalytic hydrometallation of alkynes and coupling of vinylmetalloids with olefins are discussed. Such an approach builds a new strategy for effective catalyst immobilization and its reuse, the increase of process productivity by the application of repetitive batch processes, and elimination of organic solvents, typically used in these transformations. Selected contributions in this field of chemistry are presented within this review.

2

Influence of mixing on the course of reactive extraction of citric acid using supercritical CO2

Djas M., Henczka M.

Czasopismo Techniczne. Chemia

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2016

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Y. 113, iss. 1-Ch

11--18

EN

This paper presents the investigation results of mixing effects on the course of reactive extraction of citric acid from an aqueous solution, with the use of supercritical CO2 and tertiary aliphatic amines. The influence of the mixing rate and the mixing time on the efficiency of the considered process has been studied. This paper also presents the influence of the tertiary amine chain length and the molar ratio of reactants on the efficiency of the process.

PL

W artykule przedstawiono badania dotyczące wpływu mieszania na przebieg procesu ekstrakcji reaktywnej kwasu cytrynowego z roztworu wodnego z zastosowaniem CO2 w stanie nadkrytycznym oraz trzeciorzędowych alifatycznych amin. Zbadano wpływ szybkości i czasu mieszania na efektywność rozważanego procesu. Zaprezentowano również wyniki badań wpływu długości łańcucha trzeciorzędowej aminy i stosunku molowego reagentów na efektywność procesu.

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Reactive extraction of citric acid using supercritical CO2 and trioctylamine

Djas M., Henczka M., Potocka K., Wawer J.

Challenges of Modern Technology

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2015

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Vol. 6, no. 4

27--30

EN

The paper is dedicated to the integrated process of the reactive extraction of citric acid from aqueous solution using supercritical CO2 and trioctylamine. The aim of this study is to investigate the influence of process parameters (concentration of reactants in phases, pressure, temperature, mixing rate, mixing time) on the course of the reactive extraction process. The increase of the initial concentration of amine (0.04-0.07 mol∙dm-3) results in the higher efficiency of reactive extraction. The influence of pressure (12-18 MPa) on the process is negligible. The process efficiency decreases with temperature (308-328 K). The increase of stirrer speed (250-500 rpm) leads to increase of process rate, so the final efficiency is obtained in shorter time.