Saturation-extract procedure

The reduction is effected exactly as in Procedure 8a but using 0.61 g (0.088 g-atom) of lithium. After the crude reaction product has been washed well on the filter with cold water, it is dissolved in ethyl acetate, the solution is filtered through the sintered glass funnel to remove iron compounds from the ammonia, and the filtrate is extracted with saturated salt solution. The organic layer is dried over sodium sulfate and the solvent is removed. The solid residue is crystallized from methanol (120 ml) using Darco. The mixture is cooled in an ice-bath, the solid is collected, rinsed with cold methanol, and then air-dried to give 12.9 g (85%), mp 129-132° reported for the tetrahydropyranyi ether of 3j5-hydroxypregn-5-en-20-one, mp 129-131°. 

In the second and following passes through the press, water was added to the pulp to increase the efficiency of the extraction procedure. The crude juice was screened to remove the coarse particles. Hydrogen sulfide gas was bled into the collected juice to partially saturate it. 

Reaction between TMSCH2MgCI and n-octanal in refluxing THF, followed by isolation by pouring on to ice and saturated ammonium chloride solution and normal extractive procedures gave 2-hydroxynonyltrimethylsilane, b.p. 82-83 °C/1 mmHg. 

Transfer the residue prepared as in Section 6.1.1 into a 300-nL separatory funnel with 25 mL of phosphate buffer solution (0.1 M, pH 7.4). Add 10 mL of saturated aqueous sodium chloride and 50 mL of 0.5 M sodium hydrogen carbonate to the funnel and shake the funnel vigorously for 1 min. Add 70 mL of ethyl acetate to wash the aqueous layer to the funnel, shake, separate, and discard the ethyl acetate layer. Repeat this extraction procedure three times. Add 2 mL of phosphoric acid and 20 mL of an acetate buffer solution (0.1 M, pH 4) to the aqueous layer and extract the mixmre with 50 mL of ethyl acetate three times. Combine the extracts and filter into a 500-mL round-bottom flask through 60 g of anhydrous sodium sulfate supported by a plug of cotton wool in a funnel. Concentrate the filtrate to dryness under reduced pressure. 

Solvent extraction. Extraction of neonicotinoid insecticides from water is a simple process involving saturation with sodium chloride and extraction with diethyl ether, dichloromethane or ethyl acetate. This extraction procedure will allow the simultaneous extraction of all neonicotinoids. 

In order to prevent the formation of a stable emulsion at any stage of the extraction procedure, the water content of the hydrated WPC has to be controlled so as not to obtain a biphasic solvent system during extraction with mixtures of chloroform and methanol. Besides, nonlipid contaminants are removed from the extract by gel filtration on nonlipophilic Sephadex G-25 instead of traditional aqueous washing total lipids were eluted with a 19/1 (v/v) mixture of chlo-roform/methanol, saturated with water, whereas a 1/1 (v/v) mixture of water and methanol eluted nonlipid contaminants. The method yields a similar total lipid content to the Folch method, but it is about four times faster (24). 

The activated metal Is dissolved In IINOa, the nitrates 12 min are converted to chloride, and 2 mg Co end 2 mg Fe as chloride are added. After the pprtn. of Fe by NEtOH, the filtrate Is acidified slightly with BC1, saturated with NHLiSCH, and Co la extracted with an equal volume of amyl alcohol-ethyl ether (1 1). Co Is recovered from the organic layer with 6 N NH4CH. After acidification with HC1, the above extraction procedure Is repeated. Finally, Co Is ppted. with NH4HS and mounted for counting as dried CoS or as CoO. Field = 90. ... 

Another unique feature of the interfacial reaction for metal complexes is the formation of the aggregate of the complex. As observed in many cases, the liquid/liquid interface can be saturated by any active surface molecules at the interfacial concentration of the order of 10 mol cm, which can be attained even at adiluted bulk concentration as in the case of highly hydrophobic solutes. Thus, the interface is prepared to become a two-dimensionally concentrated state for the solute. This situation very often results in the formation of the metal complex aggregates at the liquid/liquid interface. During the solvent extraction procedure for metal ions, the precipitate at the interface was observed, which was called crud or scum in the field of hydrometallurgy. This crud or scum must... 

Extraction of HemiceUuloses from Various Pulps. The extraction procedure followed was that of Giertz and McPherson (6). Fifteen grams of unaged pulps [four kinds in all bleached kraft pulp (BP), unbleached kraft pulp (UBP), unbleached groundwood pulp (GP), and chlorited UBP] was treated with 290 mL of 10.9 lithium hydroxide solution for 1 h at room temperature and was stirred intermittently (see Table I for the characteristics of the pulps). After the samples were diluted to about 1 L, the insoluble material was filtered off. The extract (filtrate) was neutralized to pH 6 with 2 M phosphoric acid (300 mL) and was allowed to stand overnight. The precipitated lithium phosphate and /3-cellulose were separated by filtration. The filtrate was then concentrated to about 175 mL under reduced pressure at 30-40 °C. Salts present in the system were further precipitated with methanol and separated by filtration. The filtrate was again concentrated to about 60 mL. The filter paper was immersed into this concentrate to saturate the test sheets. 

Dissolved metals other than calcium have a minor effect on the distribution of phosphorus between the water column and sediment in this fluvial system. The two principal metals of potential interest, iron and aluminum, are present in Genesee River water almost entirely in the particulate phase ( ). Dissolved concentrations of these metals are below the detection limit (less than 50 ug/1). Iron and aluminum minimum detectable dissolved concentrations were used to estimate the saturation levels of the corresponding phosphate minerals. These calculations suggest that both iron and aluminum phosphate minerals are substantially below saturation levels. The solid surfaces exhibited by iron and aluminum hydrous oxides (as particulate material in the water column) undoubtedly serve as sites for phosphorus adsorption and incorporation in the fluvial system. Data presented for the oxalate extraction procedure in Table III demonstrate the importance of phosphorus binding by hydrous metal oxides. 

In principle, one would also expect the homocyclic Sg to be present in hot sulfur melts but this species may be too unstable to survive the quenching and extraction procedure since never has ever a peak at the expected retention time been observed. However, according to Rau et al. [94] saturated sulfur vapor contains only 0.7 mol% Sg but 20% Sg and 12% Sy at 200 °C. At higher temperatures the melt will also contain traces of S4, S3 and S2 [61] see also the next section. The sum of the concentrations of the non-Sg rings at 116 °C is 4.87%, practically identical to the concentration of r-sulfur as derived from the freezing point depression (see above), thus confirming the reliability of the HPLC analysis. 

Catalyst characterization. The extraction procedure removed all of the remaining unchanged precursors from the zeolite surflice. The uncomplexed cobalt ions were re-exchanged, using saturated NaCl solution. Thus, all the residual cobalt present is associated with encaged cobalt(salophen). 

Solvent extraction methods usually involve partition of a salt-saturated, acidic sample aliquot with an appropriate solvent. Alternatively, the sample may be subjected to a derivatization step and a clean-up extraction prior to the acidic extraction [15]. A major drawback of the extraction procedures is an incomplete recovery of more polar acid metabolites. However, the method is simple and, consequently, more popular. The anion-exchange approach, developed initially by Horning [375], has been subjected to frequent modifications in other laboratories... 

Following gas analysis, each gold tube was cut open with clippers and the residual oil was extracted three times by sonication in pentane to obtain the saturate and aromatic residual liquid fraction The pentane extract was decanted and passed through a 0.45 pm nylon filter to recover pyrobitumen. The dry ice/acetone bath used to trap the C -Ci2 fraction during gas analysis was removed and the trap rinsed thrice with pentane and then added to the gold tube pentane extract. Details of the gas analysis and solvent extraction procedure were discussed in Hill et al (1996, 2003). 

Lipid A is composed of a disaccharide of glucosamines. The amino groups are substituted with 3-hydroxymyristate while the hydroxyl groups contain saturated (12-16 carbon) acids and 3-myris-toxymyristate. Phosphate and KDO groups are also substituted (Fig. 2.8). The fatty acids are sometimes referred to as bound fatty acids while lipopolysaccharide is bound lipid . This is because common lipid extraction procedures do not solubilize them and they... 

In many cases the esters and lactones listed above are accompanied by variable amounts of hydrocarbons (C, and higher) which may or may not be saturated. It is unknown whether these hydrocarbons are specific glandular products or artifacts of the extraction process as the higher fatty acids are thought to be. In most cases mentioned above the Dufour s gland products were obtained by extraction of the dissected gland with an organic solvent. Thus some trace chemicals listed as representative of the secretion may be indicative only of the total extraction procedure. 

Typical procedure. 2-((S)-hCYano-3-methYlbutYl)-1-(R)-phenyl-1,2,3,4-tetrahYdro-9H-pYr-ido[3,4-b]indole 1414 [1076] A solution of the amide 1413 (0.48 g, 1.33 mmol) and triethylamine (0.4 mL, 2.86 mmol) in dry dichloromethane (50 mL) was cooled to 0 °C and treated with TFAA (0.2 mL, 1.41 mmol). The mixture was allowed to warm to ambient temperature, stirred for 2 h, and then extracted with saturated aq. NaHCOs solution. The organic layer was dried over MgS04 and concentrated in vacuo (bath temperature < 30 °C). Recrystallization of the residue from diethyl... 

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