Octyl extraction

Figures 2-5 show the sorption curves of mass uptake versus time for the extract, O-methylated, O-butylated, and O-octylated extract. Three different experiments are shown in each figure a single integral sorption and two subsequent incremental sorptions. Both the extract and the O-methylated extract required 30 to 150 hours to reach equilibrium, depending on the particular experiment. The O-butylated extract sorbs benzene considerably faster, requiring less than 20 hours to reach equilibrium at all pressures. Finally, the O-octylated extract required less than one hour to reach equilibrium at each pressure.

SORPnON-DESORPTION ISOTHERMS. Sorption-desorption isotherms for the untreated, O-methylated, and O-octylated extracts are presented in Figures 6-8, where the relative vapor pressure of benzene (p/Po) is plotted against the... 

Figure 8. Sorption-desorption Isotherm for Benzene and O-Octylated Extract of Illinois No. 6 Coal...

The sorption-desorption isotherm for the O-octylated extract is noticably different. The shape of the sorption curve is concave upward and the hysteresis effect is much less pronounced. Nearly all of the benzene (97% wt) could be desorbed under vacuum at 30" C. Clearly, this material is responding much differently than the untreated and O-methylated extracts. 

EQUILIBRIUM SORPTION VALUES. The equilibrium sorption values for the extracts at various pressures of benzene are shown in Table II. The results show that O-methylated extract sorbs the most benzene at the lower pressure and that the O-octylated extract sorbs the least. At the higher pressme, the order is reversed. We believe the data shown in Table II reflect changes in the relative amounts of adsorption and absorption (swelling) with increasing size of the added alkyl groups. This interpretation is based on surface area and solubility measurements described below. 

The BET C02 surface areas of the extracts are shown in Table III. These data show that surface area decreases with increasing size of the added alkyl group. We expect that adsorption of benzene onto surfaces to be most important for the untreated and O-methylated extract and the least important for the O-octylated extract. 

Benzene solubilities of the extracts in liquid benzene at room temperature were also measured. The results, shown in Table III, show that solubility increases with inaeasing size of the added alkyl group. Interestingly, the O-butylated and O-octylated extracts showed the same solubilities in liquid benzene, suggesting that there is a limit to the amount of extract that can be rendered soluble in liquid benzene by O-alkylation. Extrapolating these results to the vapor pressure measurements, we would predict the untreated extract... 

Thus, the data in Table II can be readily explained if one considers the overall sorption process to consist of both adsorption and absorption. At low pressures, adsorption makes a relatively large contribution to the overall sorption process, and the values reflect the relative surface areas of the extracts. At higher pressures, absorption of benzene becomes relatively more important, and the equilibrium sorption values reflect the solubilities of benzene in the extract. It is interesting to note that the O-octylated extract sorbs more benzene than the O-butylated extract at the higher pressure, in spite of the fact that the O-butylated extract has a higher surface area. We conclude that benzene is more soluble in the O-octylated extract. 

As discussed above, we believe adsorption becomes less important and absorption (swelling) becomes more important as the size of the added alkyl group increases. Since the x parameter describes the "goodness" of the solvent-polymer solution, and has nothing to do with surface interactions, the more reliable x parameter will be obtained for the O-octylated extract-benzene system. Even so, the ground O-octylated extract possesses considerable surface area and any adsorption of benzene onto surfaces will lead to errors in x-Sorption experiments were therefore conducted on the unground extract, which possessed only 11 w /g surface area, x was determined to be 0.65, which was independent of pressure. 

The swelling data in Table IV can be used to calculate x parameters for the extract and O-methylated extract using Equation 1. The results are shown in Table V. The x parameters for both extracts are observed to be positive and independent of pressure or concentration of benzene. The magnitude of the parameters are much larger than that determined for the O-octylated extract (0.65) which is consistent with their lower solubilities in liquid benzene. The X parameters are much larger than those determined by Larsen el al. for the pyridine-extracted Illinois No. 6 coal, which was near 0.3.(6) The reason for this are not clear. However, we note that benzene is a very poor solvent for these pyridine-extracts so large x parameters are expected. 

Raw NBR containing 1.5% of the built-in antioxidant retained 92% of its original resistance to oxidation after exhaustive extraction with methanol. NBR containing a conventional aromatic amine antioxidant (octylated diphenyl amine) retained only 4% of its original oxidative stabiUty after similar extraction. 

Lipoteichoic acids (from gram-positive bacteria) [56411-57-5J. Extracted by hot phenol/water from disrupted cells. Nucleic acids that were also extracted were removed by treatment with nucleases. Nucleic resistant acids, proteins, polysaccharides and teichoic acids were separated from lipoteichoic acids by anion-exchange chromatography on DEAE-Sephacel or by hydrophobic interaction on octyl-Sepharose [Fischer et al. Ear J Biochem 133 523 1983]. 

Three classes of carbamoylmethylphosphoryl extractants were studied for their ability to extract selected tri-, tetra-, and hexavalent actinides from nitric acid. The three extractants are dihexyl-N,N-diethylcarbamoylmethylphosphonate (DHDECMP), hexyl hexyl-N,N-diethylcarbamoylmethylphosphinate (HHDECMP), and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphos-phine oxide 0< >D[IB]CMP0. The above three extrac-trants were compared on the basis of nitric acid and extractant dependencies for Am(III), solubility of complexes on loading with Nd(III) and U(VI), and selectivity of actinide(III) over fission products. 

This paper describes a comparison of the extraction behavior of selected. actinide(III), (IV), and (VI) ions by the dihexyl-N, N-diethyl analogs of carbamoylmethyl-phosphonate and phosphinate and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide. 

An additional material based on the extractant octyl-phenyl-N,N-diisobutyl-carbamoylmethylphosphine oxide, or CMPO, (marketed under the name TRU-Spec) has also been widely utilized for separations of transuranic actinides (Horwitz et al. 1993a) but is also useful for uranium-series separations (e.g., Burnett and Yeh 1995 Luo et al. 1997 Bourdon et al. 1999 Layne and Sims 2000). This material has even greater distribution coefficients for the uranium-series elements U (>1000), Th (>10000), and Pa. As shown in Figure 1, use of this material allows for sequential separations of Ra, Th, U, and Pa from a single aliquot on a single column. Separations of protactinium using this material (Bourdon et al. 1999) provide an alternative to liquid-liquid extractions documented in Pickett et al. (1994). 

The extractant is octyl pyrophosphoric acid (OPPA process). The stripping is by concentrated hydrofluoric acid. Yields UF4. Extracts uranium in tetravalent state. It is, therefore, necessary to use metallic iron as a reducing agent. 

A few other successful 13C 1-NMR determinations should be mentioned. Hunt et al. [28] used 13C NMR to characterise fractions of extracted analytes of PAG and sorbitan ester samples and identified Irganox 1010. H and 13C NMR have been used to identify the main organic components of a breathable diaper back-sheet as LLDPE and pentaerythritol tetra-octyl ester (PETO) [233]. The equally present AOs Irganox 1010 and Irgafos 168 were not detected without extraction. Barendswaard et al. [234] have reported fully assigned 13C solution spectra of these two antioxidants. Chimas-sorb 944 in a polyamide matrix can be determined by H or 13C 1-NMR using solvents such as formic acid, trifluoroacetic acid or trifluoroethanol [235], Both H and 13C NMR have been used to follow the chemistry of a bis-phenoxidemethylaluminum complex (reaction product of BHT and trimethylaluminum) by exposure in air. Pierre and van Bree [216] also used 13C NMR to... 

In an acetone extract from a neoprene/SBR hose compound, Lattimer et al. [92] distinguished dioctylph-thalate (m/z 390), di(r-octyl)diphenylamine (m/z 393), 1,3,5-tris(3,5-di-f-butyl-4-hydroxybenzyl)-isocyanurate m/z 783), hydrocarbon oil and a paraffin wax (numerous molecular ions in the m/z range of 200-500) by means of FD-MS. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out (Chapter 2). The method of Dinsmore and Smith [257], or a modification thereof, is normally used. Mass spectrometry (and other analytical techniques) is then used to characterise the various rubber fractions. The mass-spectral identification of numerous antioxidants (hindered phenols and aromatic amines, e.g. phenyl-/ -naphthyl-amine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinoline, butylated bisphenol-A, HPPD, poly-TMDQ, di-(t-octyl)diphenylamine) in rubber extracts by means of direct probe EI-MS with programmed heating, has been reported [252]. The main problem reported consisted of the numerous ions arising from hydrocarbon oil in the recipe. In older work, mass spectrometry has been used to qualitatively identify volatile AOs in sheet samples of SBR and rubber-type vulcanisates after extraction of the polymer with acetone [51,246]. 

Alkyl esters of phosphoric acid and phosphine oxides will extract metals and mineral acids by direct solvation. Tri-//-butyl phosphate (TBP) and tri- -octyl phosphine oxide (TOPO)... 

Water/SPM Collect water samples on disposable octyl-bonded silica solid-phase extraction columns dry elute with hexane/ether SPM collected by continuous flow centrifugation extract with acetone/water/benzene GC/ECD GC/MS O.lpg/L (water) 0.1 mg/kg (suspended particulate) 83 (water) 82 (suspended particulate) Ritsema et al. 1989... 

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