Toluene extraction

The sodium salt of methyl red may be prepared by dissolving the crude product in an equal weight of 35 per cent, sodium hydroxide which has been diluted to 350 ml., hitoring, and evaporating under diminished pressure (Fig. II, 37, I). The resulting sodium salt forms orange leaflets. This water-soluble product is very convenient for use as an indicator. Incidentally, the toluene extraction is avoided. 

For analysis, white phosphoms is typically extracted through a fritted thimble with refluxed toluene. Any trace amounts of water are captured in a cahbrated sidearm to the apparatus. The soflds on the frit are weighed, the water measured, and the phosphoms calculated by difference. For impure samples of phosphoms, the toluene extract may be analy2ed with a gas chromatograph (gc) equipped with a phosphoms—nitrogen detector. 

Interaction of formaldehyde with 2,4-dinitrophenylhydrazine in acid media causes 2,4-dinitrophenylhydrazone (DNPhydrazone) formaldehyde formation. Gas-chromatographic analysis of 2,4-DNP-hydrazone formaldehyde toluene extract with an electron holding detector makes it possible to detect it at the level of 0,001 mg/dm. Phenol is detected in the form of tribromphenol yield, the hexane extract of which undergoes chromatography with an electron holding detector which provides the level of phenol detection of 0.001 mg/dm (the limit of quantitative detection). 

Toluene (methylbenzene) is similar to benzene as a mononuclear aromatic, but it is more active due to presence of tbe electron-donating metbyl group. However, toluene is much less useful than benzene because it produces more polysubstituted products. Most of tbe toluene extracted for cbemical use is converted to benzene via dealkylation or disproportionation. Tbe rest is used to produce a limited number of petro-cbemicals. Tbe main reactions related to tbe cbemical use of toluene (other than conversion to benzene) are the oxidation of the methyl substituent and the hydrogenation of the phenyl group. Electrophilic substitution is limited to the nitration of toluene for producing mono-nitrotoluene and dinitrotoluenes. These compounds are important synthetic intermediates. 

Quantitatively transfer the hydrolysis reaction solution to a 50-mL glass culture tube with a screw-cap by rinsing witli 3x5 mL of deionized water followed by 5 mL of 30% (v/v) sulfuric acid and one additional 5 mL of deionized water. Rinse the Teflon culture tube with acetone and transfer to the glass culture tube. Extract the acidic aqueous phase (pH 1) with 3 x 2.5 mL of toluene. Pass each upper toluene phase through approximately 3 g of anhydrous sodium sulfate contained in a 6-mL disposable filtration cartridge into a 10-mL volumetric flask. Adjust the volume of the solution to 10 mL with toluene. Condition a 3-mL diolsilane bonded silica gel SPE cartridge with two column volumes of toluene. Load a 5-mL aliquot of toluene solution and collect the eluate in a 125-mL round-bottom flask. Elute the column with an additional 50 mL of toluene (use the 75-mL reservoirs) and collect the eluate in the same round-bottom flask. Concentrate the toluene extract to approximately 3.0 mL at 40 °C under weak reduced pressure with a rotary evaporator. 

Static(batch) and dynamic(flow) tests were carried out on toluene - extracted and peroxide - treated Wilmington oil field unconsolidated sands with dilute solutions of polyacrylamide (Dow Pusher-500) polymer in 1 wt% NaCl at 50° C and 1.5 ft./day, simulating reservoir temperature and flow rates. In the static tests, Ottawa sand, with particle size distributions similar to the Wilmington sand, were also used for comparison purposes. 

Figure 28 Positive APCI chromatogram obtained for the toluene extract from a clear polypropylene material (after precipitation of polymer with methanol) spiked with diparamethyldibenzylidene sorbitol (antioxidants also detected).

Murakami, Y. and K. Horiuchi, Simultaneous Determination Method of Radon-222 and Radon-220 by a Toluene Extraction-Liquid Scintillation Counter, J. Radioanal. Chem. 52(2) 275-283, (1979). 

Aluminium Extraction with trifluoro-acetyl acetone in toluene Analysis of toluene extract by GC 6 pg A1 in 2 xl extract [18]... 

The first spectrofluorimetric methods reported for the determination of nalidixic acid and its metabolites in biological fluids did not differentiate between nalidixic acid and hydroxynalidixic acid. The determination of free nalidixic acid and the hydroxy-metabolite in human urine plasma and feces was performed by extraction by toluene from acidified biological fluid and subsequent fluorimetric measurement at 325/375 nm of sample re-extracted into aqueous solution.(8) Conjugated nalidixic and hydroxynalidixic acids were determined by acid hydrolysis and then toluene extraction for fluorimetric measurement of the total drug. The conjugated nalidixic acid was then determined by difference. 

Gas chromatography of the benzene or toluene extracts was carried out on a borosilicate glass column (180cmx3mm o.d.) packed with 5% DC-200 and 7.5% QF-1 on Chromosorb W (80-100 mesh) operated at 190°C with nitrogen or argon as carrier gas and electron capture detection. Major peaks were obtained for S4, S6 and S8. Down to lpg L 1 of sulphur could be determined in the aromatic solvent extracts. 

Sulphuric acid-perchloric acid digestion-spectrophotometry Toluene extraction, bromo derivitization, glc Cold vapour aas... 

Drying of the toluene extract is unnecessary, since the water is carried over during the removal of the toluene. If necessary, the toluene may be returned once to the flask to effect complete removal of the water. 

Because ethyl alcohol forms an azeotrope with water that is a constant boiling mixture, i.e. both the ethyl alcohol and the water, in a ratio of 95/5, boil together at a temperature different than either separately. Other examples in this chapter are the ternary azeotrope, ethyl alcohol - water -benzene and DIPE - isopropyl alcohol - water. An azeotrope mentioned earlier is MEK - water - toluene rafFmate used for toluene extraction. 

As indicated previously, it is important to look at the individual trace elements in the coal extract solution. Table 9 shows the concentration of trace elements in the ash from the original extract and the filtrate produced after toluene extraction. This was for an extract with an ash level of 350 ppm, extracted with toluene at 165 C to give a filtrate with an ash level of 100 ppm. The results show that there are some differences, with Ca reducing and Fe and Ti increasing their proportions. However, the changes are not great and it would be expected that if the filtrate were fed to the hydrocracker it would deposit trace elements as observed previously Q), except, of course, there would be a smaller quantity overall. 

When toluene extractions were carried out at 110°C, it was clear from the mass obtained, that toluene remained in the filtrate. With the higher temperature extractions, remembering that the filtration was also carried out at the higher temperature, the mass of filtrate was accordingly lower, since most of the toluene boiled off from the filtrate. 

Numerous bisphenols of the general structure 10 were detected in both the ether and toluene extracts of the transalkylation products from the fresh and oxidized coal samples. 

Table II contains a list of the aliphatic bridges detected in the toluene extract. Compounds with methylene bridges were predominant in the products from the fresh coal. This is consistent with the results of Benjamin et al. . It is interesting to note that several branched chain bridges appear in the transalkylation products from both the fresh and oxidized coals.

The concentrations are reported as a fraction of the toluene extract from the transalkylation reaction. As a result of oxidation, concentrations of the most abundant bridges, namely methylene, ethylene, methyl methylene, and ethyl methylene groups are reduced by factors of 6, 14, 6, and 9, respectively. The differences in the... 

Figure 1.9 FT-ICR mass spectrum of hot toluene extract produced by laser vaporization of a lanthanum oxide-graphite composite rod [66].

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