Cyclohexanes methylene

Cyclohexane, methylene-, 40, 66 Cyclohexanecarboxylic acid, 3,4,5-TRIACETOXY-, 42, 62 Cyclohexanecarboxylic acid, 3,4,5-iriol, 42, 62... 

Cyclobutanone, see Atrazine Cycloheptanol, see Cycloheptane Cyclohexane, Methylene chloride Cyclohexanol, see Cyclohexane. Pentachlorophenol Cyclohexanone, see Cyclohexane. Cyclohexanol. 

Analysis of PCBs. PCB residues in extracts of egg samples were enriched by using a combination of gel permeation chromatography on BioBeads S-X3 and 1 1 (v/v) cyclohexane. methylene chloride. Adsorption column chromatography on silicic acid was used to separate PCBs from other co-extractives and contaminants (15). 

Gordon, L.J. and Scott, R.L. Enhanced solubility in solvent mixtures I. The system phenanthrene cyclohexane-methylene iodid ,Am. Chem. Soc., 74, 4138-4140, 1952. 

FIGURE 5.41 Molecular models showing diastereomers of the A-sym-cis-R,R-cdda complex with respect to the absolute configurations of the coordinated asymmetric nitrogens and the normal axial (a) and abnormal equatorial (b) orientations of the terminal acetate rings. The solid circles in (a) refer to the acetate and the cyclohexane methylene of which the protons suffer severe steric contact as shown by arrows.170... 

Analyses were performed by HPLC using a Shimadzu LC-6A pump and UV Spectrophotometer SPD-6A detector. The columns used wei e Phenomenex Rezex monosaccharide-H+ with trifluoroacetic acid (lO M) as the mobile phase for toluene as the solvent, and Spherisorb-CN with cyclohexane/methylene chloride/isopropanol (80/16/4 by volume) as the mobile phase for methyl isobutyl ketone as the solvent. 

BaA and BaP is added and the entire sample is extracted with methylene chloride (250-, 100-, and 100-mL portions). The extracts are combined, 10 mL of isooctane added, and the solution evaporated to about 10 mL. When the solution approaches 10 mL, a second 10-mL volume of isooctane is added. This is repeated three times. The isooctane solution is made up to 75 mL and extracted with three 100-mL portions of dimethyl sulfoxide (DMSO) that contains 20% phosphoric acid. The DMSO extracts are each washed with three 30-mL portions of fresh isooctane, combined and diluted with 500 mL of water. This solution is extracted with three 80-mL portions of isooctane. The isooctane extracts are combined, rinsed once with water, and evaporated to 25 mL. At this point, a 1-mL portion of the solution is removed for intermediate radioassay and a UV scan. Usually the concentrate is sufficiently free from interferences and is evaporated down to about 0.05 mL and an aliquot injected into the GC. If further purification is indicated, the solution is chromatographed on a 1.1-cm X 90-cm column containing 75 g of Woelm Neutral Alumina deactivated with 2% water. Before deactivation, the alumina is dried in an oven for 1 hr at 150°C. The solvent elution schedule is as follows 25 mL cyclohexane prewash, 25-mL sample in cyclohexane, 100 mL cyclohexane, 100 mL cyclohexane-methylene chloride (9 1), 100 mL cyclohexane-methylene chloride (1 1), 100 mL methylene chloride. After the first 125 mL has eluted, 10 cuts are then radioassayed and combined into a single PNA fraction. This fraction is evaporated to about 0.05 mL in preparation for the GC-UV finishing step. Figure 2 is a diagram of the wastewater procedure. 

Figure 1.14 Solubility of phenanthrene in cyclohexane-methylene iodide mixtures. (Reprinted with permission from L.J. Gordon and R.L. Scott, Enhanced Methylene Iodide Solubility in Solvent Mixtures. I. The System Phenanthrene—Cyclohexane-Methylene Iodide, J. Am. Chem. Soc. 74, 4138. 1952 American Chemical Society.)...

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