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Wyszukujesz frazę "steric effect" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Sterical index: a novel, simple tool for the interpretation of organic reaction mechanisms
Autorzy:
Dresler, Ewa
Allnajar, Radwan
Jasiński, Radomir
Powiązania:
https://bibliotekanauki.pl/articles/35125599.pdf
Data publikacji:
2023
Wydawca:
Radomskie Towarzystwo Naukowe
Tematy:
organic reactivity
steric effect
cycloaddition
reaktywność organiczna
efekt steryczny
cykloaddycja
Opis:
A new, simple index for the quantitative description of steric effects was proposed based on the results of DFT calculations. This effect was connected with the disturbance of synchronicity within transition states of the model Diels-Alder reaction. The obtained results offer the possibility of predicting steric effects determined by alkyl groups for a wide range of bimolecular processes.
Źródło:
Scientiae Radices; 2023, 2, 1; 69-74
2956-4808
Pojawia się w:
Scientiae Radices
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of the steric effect of the carrier molecule in the polymer inclusion membranes for the separation of cobalt(II), nickel(II), copper(II), and zinc(II) ions
Autorzy:
Radzyminska-Lenarcik, E.
Ulewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/778754.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
polymer inclusion membrane
separation ions
steric effect
copper(II)
cobalt(II)
nickel(II)
cadmium(II)
zinc(II)
alkylimidazole
Opis:
In this study, palladium-modified nickel foam substrate was applied to examine ethanol oxidation reaction (EOR) in 0.1 The transport of cobalt(II), nickel(II), copper(II), and zinc(II) ions from chloride solutions across polymer inclusion membranes (PIMs), which 1-heptylimidazole (1̲) or 1-heptyl-2-methylimidazole (2̲) or 1-heptyl-4-methylimidazole (3̲) as the ion carrier was reported. The steric effect for carriers 2̲&enspand 3̲&enspdecreases the transport of all ions except Cu(II). The initial fluxes of metal ions transport across PIMs with the 1̲- 2̲&enspdecrease in the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II), whereas for 3 they were Cu(II) > Zn(II) > Ni(II) > Co(II). The highest recovery values were obtained for Cu(II), this being 99 and 85% for carrier 1̲&enspand 2̲, respectively. In both membranes the degree of deposition of the Zn(II) ions was comparable. Zn(II), Co(II) and Cd(II) ions, which form complexes with coordination numbers 4 and 6, are more easily recovered with the use of carriers 2̲&enspand 3̲. Ni(II) ions, which form complexes with coordination number 6 only, practically remain in the feeding phase. PIMs with alkylimidazoles were characterized by non-contact atomic force microscopy.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 2; 51-56
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of ethylene oxide groups in dodecylamine polyoxyethylene ether on rutile flotation
Autorzy:
Huang, Junwei
Chen, Qian
Mao, Yuxuan
Li, Hongqiang
Powiązania:
https://bibliotekanauki.pl/articles/1448539.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rutile flotation
dodecylamine polyoxyethylene ether
ethylene oxide groups
steric hinder effect
adsorption mechanism
Opis:
To study the number of ethylene oxide (EO) groups effect on the flotation of rutile, three collectors with different EO number were evaluated: AC1203 (with three EO number), AC1210 (with ten EO number), AC1215 (with fifteen EO number). In addition to the flotation experiments, zeta potential measurements, collector adsorption experiments and XPS analysis were conducted to elucidate the adsorption mechanism. The results of flotation demonstrated that dodecylamine polyoxyethylene ether exhibited a profound collecting ability towards rutile mineral, it was worth mentioned that the recovery of rutile decreased with the increase of EO number. On the basis of zeta potential tests and XPS analysis, both protonated and neutral tertiary amine groups could act with rutile surface through electrostatic effect and hydrogen bond interaction. Furthermore, the results of collector adsorption experiments showed that with the increase of EO number, a lower adsorption density of collectors on rutile surface could be caused due to the steric hinder effects.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 127-135
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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