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1.
The extraction properties of the sulphide podand 1,12-di-2-thienyl-2,5,8,11-tetrathiadodecane (TTD), an open-chain neutral polythioether with six sulphur donor atoms in 1,2-dichloroethane, chloroform and MIBK for Pd and Au in hydrochloric, nitric and perchloric acid media have been examined. The kinetic aspects of the extraction of palladium(II) from hydrochloric acid by TTD and dioctyl sulphide (DOS) were compared. The rate of Pd extraction with TTD is considerably higher than that with DOS, especially with chloroform. Combined use of a reducing agent and TTD enhances the extraction of gold(III) into 1,2-dichloroethane. 相似文献
2.
An extraction-AAS method of determination of Co, Ni, and Mn in metallurgical copper materials containing considerable amounts ofCu, Fe, Pb, Zn, and Al has been developed. Good selectivity of group separation of Co, Ni, and Mn has been achieved by (a) the use of tetrabutylammonium bromide to improve extractability of HTTA complexes by ion-pair formation, and (b) the masking of major elements with sodium thiosulphate and sulphosalicylic acid. The extracts are stable for at least 3 weeks. 相似文献
3.
E. Lachowicz B. R
a
ska F. Teixidor H. Meliani M. Barboiu N. Hovnanian 《Journal of membrane science》2002,210(2):279-290
The reactivity of new ligands described as S1, S5, S2O9 (in respect to character and amount of donors) towards metal ions was examined by extraction from HNO3 and HCl media. These ligands were next utilised as carriers for Ag and Pd transport through a supported liquid membrane (SLM). The effect of collecting a greater number of S donors in one molecule and the influence of type of donors (O–S versus S) on efficiency and selectivity of Ag and Pd(II) extraction and transport were examined.
The extraction of Ag from HNO3 solutions increased with increasing amount of S-donors in one molecule (S12O95). For palladium the sequence was different (S512O9). The transport of Ag through SLM impregnated with m-chlorotoluene solution of ionophore increased in the same order as in the case of extraction, whereas for Pd the row was different: S52O91. The highest fluxes of Ag and Pd transported from HNO3 equalled to 5.25×10−7 and 1.37×10−7 mol/m2 s, respectively. Palladium flux depended on stripping solution type (Na2S2O3
4.
5.
Elwira Chrobak Ewa Michalik Joachim Kusz Maria Nowak Stanisaw Boryczka 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(9):847-851
The lupane triterpenoid betulonic aldehyde [also known as betulonal; systematic name: lup‐20(29)‐en‐28‐al‐3‐one, C30H46O2] is a product of betulin oxidation. Crystals were obtained from hexane [form (I)] and dimethyl sulfoxide [form (II)] solutions. Forms (I) and (II) are both orthorhombic. The molecular geometric parameters in the two forms are similar, but the structures are different with respect to the crystal packing. Polymorph (I) contains two independent molecules in the asymmetric unit, while polymorph (II) contains only one molecule, which has a disordered aldehyde group [the disorder ratio is 0.769 (4):0.231 (4)]. In each molecule, the six‐membered rings have chair conformations, whereas the cyclopentane ring in each molecule adopts an envelope conformation. All the rings in the lupane nucleus are trans‐fused. The extended structures of both polymorphs are stabilized by weak intermolecular C—H...O and van der Waals interactions. Weak intramolecular C—H...O interactions are also observed. 相似文献
6.
Ohne Zusammenfassung 相似文献
7.
Dr. Br. Lachowicz 《Monatshefte für Chemie / Chemical Monthly》1893,14(1):279-293
Ohne Zusammenfassung 相似文献
8.
Dr. Br. Lachowicz 《Monatshefte für Chemie / Chemical Monthly》1888,9(1):505-509
Ohne Zusammenfassung 相似文献
9.
An asymptotic equivalence theorem is proven between the solutions of the initial value problem in all space for the Boltzmann and Enskog equations for initial data which assure global existence for the solutions to the initial value problem for one of the two equations. The proof is given starting from the solution of the Boltzmann equation, then the proof line is simply indicated when one starts from the Enskog equation. The proof holds for Knudsen numbers of the order of unity and equivalence is proven when the scale of the dimensions of the gas particles characterizing the Enskog equation tends to zero.On leave from Department of Mathematics, University of Warsaw, Poland. 相似文献
10.
A reliable technique for cryopreservation by encapsulation was developed for two suspension cultures of gentian species (Gentiana tibetica and G. cruciata) of different ages and embryogenic potential. The effect of water content, aggregate size and the subculture time on viability was determined by the 2,3,5-triphenyltetrazolium chloride (TTC) test. Regrowth of a proembryogenic mass (PEM) on agar, liquid or agar/liquid media was assayed by measuring the increase in biomass. A water content of 24-30% (fresh weight basis) after 5-6 h dehydration of encapsulated cells of gentians yielded the highest survival (68% for G. tibetica and 83% for G. cruciata) after cryopreservation. Regardless of species, aggregate size and subculture time, the lowest PEM survival was 44%. These parameters did not influence the survival of G. tibetica PEM, but the survival of G. cruciata was higher when the smaller aggregates were cryopreserved on the 5th day of culture. Agar/liquid culture caused the greatest biomass increase. Cryopreservation did not affect the characteristics of suspension cultures and their regrowth after thawing, nor the number and dynamics of somatic embryos formed. Flow cytometry showed that cryopreservation did not change the genome size of the PEMs or regenerants. 相似文献