Macrocyclic extractants

The dried products were analyzed for the low molecular weight extractable macrocyclic fraction (described under Analyses). 

CO Polymerization Effect of Conversion on Low Molecular Weight Macrocyclics. A series of polymerizations of cyclooctene was carried out in a manner similar to that described above, using a constant monomer concentration of 1.57M. The polymerizations were terminated at various reaction times, thus obtaining different conversions. The products were isolated, processed, and analyzed for percent extractable macrocyclics as described previously. 

CDT Polymerization. Following the general polymerization procedure described above, 1,5,9-cyclododecatriene was polymerized using 100 ml. of 1.57M solution of monomer in benzene and initiated by 2.0 ml. each of the catalyst Components A and B. The reaction was terminated after 30 minutes, and the product was isolated, processed, and analyzed for the low molecular weight extractable macrocyclic fraction as before. 

The material was analyzed for newly formed low molecular weight extractable macrocyclics (see Analyses). 

Figure 1. Dependence of extractable macrocyclics on reciprocal of initial monomer concentration, [M]0. Polymerizations conducted at [W] = 5 X 10r4 and [A/] = 2 X 10 3 for 30 minutes at room temperature. Conversion ...

Figure 4. Comparison of chromatograms of 1,5-cyclooctadiene extractable macrocyclics with standard reference materials...

Figure 6. Comparison of cyclooctene extractable macrocyclics obtained by catalyst treatment of high molecular weight polyoctenamer with extractable macrocyclics obtained during cyclooctene polymerization...

Figure 8. NMR spectra of polyoctenamer, extractable macrocyclic fraction from polyoctenamer and polyoctenamer obtained by polymerization of the extractable macrocyclic fraction...

The low molecular weight extracted macrocyclics can be converted to high molecular weight polymer, whose structure is indistinguishable from polymer prepared by the normal polymerization of the respective cycloolefin monomer. 

Macrocyclic ligands such as crown ethers have been widely used for metal ion extraction, the basis for metal ion selectivity being the structure and cavity size of the crown ether. The hydrophobicity of the ligand can be adjusted by attachment of alkyl or aromatic ligands to the crown. Impressive results have been obtained with dicyclohexano-18-crown-6 as an extractant for Sr in [RMIM][(CF3S02)2N] IL/aque-... 

Hydrazine, bis(allylthiocarbamido)-in gravimetry, 1, 534 liquid-liquid extraction, 1,546 Hydrazines, 2, 101 macrocyclic synthesis, 2,904 metal complexes, 2, 30 in plutonium extraction, 6, 948 Hydrazoic acid... 

Cyclodextrins can solubilize hydrophobic molecules in aqueous media through complex formation (5-8). A nonpolar species prefers the protective environment of the CDx cavity to the hulk aqueous solvent. In addition, cyclodextrins create a degree of structural rigidity and molecular organization for the included species. As a result of these characteristics, these macrocycles are used in studies of fluorescence and phosphorescence enhancement (9-11), stereoselective catalysis (.12,13), and reverse-phase chromatographic separations of structurally similar molecules (14,15). These same complexing abilities make cyclodextrins useful in solvent extraction. 

Ivermectin, a macrocyclic lactone, is also utilized to control parasites. An immunoassay was developed to determine ivermectin residues in bovine liver by Crooks etal. The sample preparation procedure was complex, involving tissue homogenization in acetonitrile, centrifugation, extraction with hexane (to remove lipids), evaporation and reconstitution in ethyl acetate, and passage through an SPE column followed... 

Our most recent work with B megapotamica has been with the isolation of large quantities of baccharinoids from a 1800 Kg collection. The workup of the crude extract (ca. 30 Kg of black tarry material) of this plant material was conducted by Dr. Fred Boettner of Polyscience, Inc. This near Herculean task required tremendous quantities of solvents, column packings and time to complete. An outline of the fractionation scheme is presented in Figure 2. Fractions F6-F11 contain a large number of baccharinoids. To date, we have characterized over twenty macrocyclic trichothecenes found in B mega-... 

Mixed N/O donor macrocycles (93) have been used to extract metals from solution via competitive metal transport.73... 

Yordanov, A. T. Roundhill, D. M. Solution extraction of transition and post-transition heavy and precious metals by chelate and macrocyclic ligands. Coord. Chem. Rev. 1998, 170, 93-124. 

The series of derivatives of diaza-18-crown-6 illustrated by (182) have also been used for extraction studies involving Li+, Na+ and K+ picrates in a CH2Cl2/water system (Cho Chang, 1980). Relative to the parent macrocycle, all the N,/V -derivatives led to enhanced extraction of these ions although the selectivities observed for the parent system were moderated somewhat. 

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