System chloroform

Moderate errors in the total pressure calculations occur for the systems chloroform-ethanol-n-heptane and chloroform-acetone-methanol. Here strong hydrogen bonding between chloroform and alcohol creates unusual deviations from ideality for both alcohol-chloroform systems, the activity coefficients show... 

If the molecular species in the liquid tend to form complexes, the system will have negative deviations and activity coefficients less than unity, eg, the system chloroform—ethyl acetate. In a2eotropic and extractive distillation (see Distillation, azeotropic and extractive) and in Hquid-Hquid extraction, nonideal Hquid behavior is used to enhance component separation (see Extraction, liquid—liquid). An extensive discussion on the selection of nonideal addition agents is available (17). 

Figure 2. Thin-layer radiochromatogram of urine (100 il) from rats injected with labeled PbTx-3. TLC plates were developed in two sequential solvent systems chloroform ethyl acetate ethanol (50 25 25 80 10 10). Radioactive zones were scraped and counted in a liquid scintillation counter. Native PbTx-3 runs at 13 cm.

For the stripping and rectifying sections to become a feasible column, the two operation leaves must overlap. Figure 12.20 shows the system chloroform, benzene and acetone. The operation leaf for a distillate composition D intersects with the operation leaf for a bottoms composition... 

Phosphorus, fatty acids, carbohydrates, glycerol, and amino acids were analyzed by the method described in our previous paper [8] and references cited therein. SDS-PAGE [8], TLC [9], HPLC [9], determination of phos-phomonoester [8], reducing sugar analysis [13], methylation analysis [14], and hexose analysis [15] were performed as described in the respective literature. Two dimensional TLC was performed on silica-gel plate (Merck Silicagel 60 F254 No. 5715) using the solvent systems, chloroform-methanol-acetic acid (65/10/1, v/v/v) for the first development and chloroform-methanol-25% ammonia solution (65/10/1) for the second. 

Solvent methanol Solvent system chloroform/methanol (4/1)... 

Figure 1 shows the scheme for the preparation of purified lipid A from endotoxin. S. typhimurium G30/C21 was extracted by the method of Galanos t aK (24) and submitted to one of two different conditions of hydrolysis (a) 0.1 N HC1 [in methanol-water (1 1, v/v)], 100 °C, 45 min, to yield the crude monophosphoryl lipid A (nontoxic), and (b) 0.02 M sodium acetate, pH 4.5, 100 °C for 30 min (two cycles) to yield the crude diphosphoryl lipid A (toxic). The 0.1 N HC1 hydrolysis product was fractionated on a Sephadex LH-20 column (23). Each of these fractions was then separated by preparative thin layer chromatography (TLC) on silica gel H (500 ym), with the solvent system chloroform-methanol-waterconcentrated ammonium hydroxide (50 25 4 2, v/v) as previously described (23) to yield TLC fractions 1-7 and 1-9 respectively. 

Glycolipid 11, Table 1 (2) glycolipid 9, Table 11 (3) glycolipid 10, Table I. Solvent system chloroform/ methanol/ water (60/ 35/8, v/v/v). Visualization orcinol reagent. (26)... 

Fucolipid 19, Table I (2) fucolipid 20, Table I (3), jucolipid 21, Table I (4) fuco-lipid 22, Table 1. Solvent system chloroform/acetone/methanol/ water (52/40/00/4, by volume), plate A 1,2-dichloroethane/methanol/water (80/25/2, v/v/vj, plate B 1,2-dichloroethane/acetone/methanol/water (50/40/10/4, by volume), plate C. Visualization orcinol reagent. (52)... 

The toxicities of alkyl halides vary a great deal with the compound. Although some of these compounds have been considered to be almost completely safe in the past, there is a marked tendency to regard each with more caution as additional health and animal toxicity study data become available. Perhaps the most universal toxic effect of alkyl halides is depression of the central nervous system. Chloroform, CHC13, was the first widely used general anesthetic, although many surgical patients were accidentally killed by it. 

It was put into a separating funnel and shook with 1 L ethyl acetate and 200 ml of 5% sodium hydroxide. The an organic layer was separated, with 2-3 L water washed (portions 400-500 ml), dried over sodium sulfate and distilled in vacuum to dryness at about 60°C. 121.2 g crude proscillaridin-2,3-ethyl orto-formiate yielded. It was dissolved in 1 L dimethylformamide, mixed with 200 ml methyl iodide and stirred with 20 g 55-60% suspension of sodium hydride at 20°C for 1 hour. 14 L ethyl acetate was added, 5 times with 1-2 L water shook and the organic layer was distilled to 1/4 of volume. The solution of proscillaridin-2,3-ethyl ortho-formiate-4-methyl ester obtained (about 1 L) was mixed with 2 L 0.002 N HCI and stood for 2 hours at 20°C. Then it was neutralized with 0.1 N sodium hydroxide and distilled in vacuum to about 1 L. The solution was shook with 2 L chloroform and 1 L water, organic layer was separated, water layer was 2 times was extracted with still 1 L chloroform and the pooled organic phase dried over sodium sulfate. Then the solvent was removed and 147 g of obtained product was purified by chromatography on silica gel in system chloroform/acetone 4 1. 

Fig. 7 Membranes can be formed by components of carbonaceous meteorites [69,70]. a The Murchison meteorite contains approximately 2% organic carbon by weight, b Organic compounds can be extracted from the meteorite by a lipid solvent system (chloroform-methanol), then separated by two-dimensional chromatography. Polycyclic compounds in the mixture produce fluorescent spots, c The organic acid fraction from the TLC plate readily assembles into membranous vesicles when exposed to dilute aqueous solutions buffered at pH 8-9. The vesicles were photographed by their autofluorescence. Scale bar shows 20 im...

Geveke, D.J. Danner, R.P., "Application of the Flory-Huggins Theory to the System Chloroform-Polystyrene-Butadiene Rubber," Polym. Eng. Sci., 31, 1527 (1991). 

The sizes determined in this work are the apparent molecular sizes and not necessarily the sizes of the asphaltene and maltene molecules at process conditions. Association efforts for asphaltene molecules have been observed for both vapor-phase osmometry molecular weight and viscosity measurements (14, 15). The sizes reported here were measured at 0.1 wt % in tetrahydrofuran at room temperature. Other solvent systems (chloroform, 5% methanol-chloroform, and 10% trichlorobenzene-chloroform) gave similar size distributions. Under these conditions, association effects should be minimized but may still be present. At process conditions (650-850°F and 5-30% asphaltene concentration in a maltene solvent), the asphaltene sizes may be smaller. However, for this work the apparent sizes determined can be meaningfully correlated with catalyst pore size distributions to give reasonable explanations of the observed differences in asphaltene and maltene process-abilities (vide infra). In addition, the relative size distributions of the six residua are useful in explaining the different processing severities required for the various stocks. Therefore, the apparent sizes determined here have some physical significance and will be referred to just as sizes. 

The excess Gibbs energy for the system chloroform(l)/ethanol(2) at 55 C is well represented by the Margules equation, written ... 

The large difference between the two calculated values is due to the fact that the expression (5.14) varies as the fourth power of /x. It would appear reasonable to attribute the mixing properties of acetone -f- carbon disulphide mainly to the dipolar interaction, but other types of intermolecular force must play a significant part in the system chloroform -f carbon disulphide. 

One quite remarkable comparative separation of flavonoids by DCCC, RLCC, and cartridge and multilayer coil CPC methods, with the same solvent system (chloroform-methanol-water, 33 40 27), is shown in Fig. 

Fig. 1 Chromatograms of hesperetin (1), kaempferol (2), and quercetin (3) by different countercurrent chromatographic methods. Solvent system chloroform-methanol-water (33 40 27). (A) DCCC (B) RLCC (C) multilayer coil CPC system and (D) cartridge CPC system. (Elsevier Science Ireland, Ltd.)...

In Table 1, the various two-phase solvent systems are divided into four types. It has been shown that the solvent system chloroform-methanol-water has been used for the greatest number of applications. CHCl3 CH30H H20 is a versatile CCC solvent system for flavonoid separations as well. 

Fig. 1 HSCCC separation of bacitracin components. Solvent system chloroform/ethanol/methanol/water (5 3 3 4) mobile phase lower phase flow rate 3 mL/min detection 254 nm.

Conjugated bile acids and bile alcohols were analyzed by TLC using silica gel G plates (Brinkmann Instruments, Westbury, NJ 0.25-mm thickness) with the solvent system chloroform/methanol/acetic acid/water 26 8 4 2 (v/v/vA) (5,7,9). Bile salts were made visible with a spray reagent which consisted of 10 % phosphomolybdic acid in ethanol. Detection with naphthoresorcinol (0.2 % in... 

Fig. 24.6. Thermodynamic excess functions for the system chloroform + acetone at 25 °C.f...

Kajganovic (90) have used Bratton-Marshall reagent for quantitation after separation and elution of sulfonamide mixtures containing sulfacetamide. The solvent system chloroform-methanol-25% ammonia solution (90 15 2.4) gives good separation. The results show a relative standard deviation of about 4%. Sarsunova et al. (86) have used chloroform-ethanol (100 8) as solvent system for the separation of sulfacetamide, sulfathiazole and sulfadimidine in tablets. The sulfonamides are assayed by extraction with acetone-ethanol, separation on alumina, and determination at 270 and 290 nm. The relative standard deviations of 2.5%, 4.1% and 3.2% have been obtained for the three components with six replicates. 

Up to now, isotopic separations in extraction systems have been investigated for calcium by Jepson and DeWitt as well as by Heumann and Schieferfor lithium by Jepson and Cairns and for sodium by Knochel and Wilken In these investigations the system chloroform/water was mainly used. Jepson and DeWitt have also carried out experiments with methylene chloride but no detailed results have been submitted about this system. 

An oxygen analogue, the 3-(2iH)-benzofuranone, reacted with aryllead triacetate to afford either the mono or the diaryl derivative. In the usual system (chloroform, pyridine), only modest yields were obtained, but use of -tetramethylguanidine (TMG) allowed the reaction to proceed in better... 

An example of the harmful effects of the multiple use of the solvent system is shown in Fig. 51. Four plates, each with two 10-mm lanes, each containing 20 pg metoc-lopramide hydrochloride, were developed successively with the solvent system chloroform + methanol + concentrated ammonia solution (56 + 14 + 1 ml). The continuous downwards shift of the hRf value can be clearly seen, combined with an increasing broadening of the spots of the substance during the chromatography. These effects were caused by the reduction in the amount of base in the remaining solvent. 

Figure 44. Influence of traces of water in the ethanol nsed to stahiUze the solvent system chloroform...

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