Toluene removal

Figure 3.19a Screening external MSAs for the toluene-removal example,...

Employ linear programming to find the MOC solution for the toluene-removal example described in Section 3.10 (Example 3.3). 

In the case of the hot-rod reactor experiments, the toluene solutions were combined and the toluene removed under reduced pressure. n-Hexane (250 ml) was added to the extract and it was allowed to stand for 24 hours with occasional shaking. The solution was filtered to leave a residue (asphaltene) and the hexane was removed from the filtrate under reduced pressure to give the oil. 

Although photocatalytic oxidation is generally applied to only low concentrations of gas-phase contaminants, typically in the ppm range, several smdies have addressed higher concentrations as well. Augugliaro et al. [14] and Martra et al. [16] evaluated the photocatalytic oxidation of toluene at concentrations of up to 1.3 mol% in air. At these high concentrations, significant levels of gas-phase intermediate products were observed. Of the toluene removed from the gas phase in the photocatalytic system, nearly 20% was converted into benzaldehyde, as... 

Note The rapid production during WWII of a huge supply of TNT (obtained by nitration of plentiful petroleum toluene), removed the necessity of using AN as a substitute for TNT. Another factor contributing to the disuse of amatols as military expls was the appearance during WWII of materials more powerful than TNT, such as PETN and RDX, as well as their binary mixts pentolites, cyclotols, etc... 

If heating is desired to speed the toluene removal, a steam or an oil bath is used to prevent charring of the salt. 

Cognate preparation, p-Dinitrobenzene. Use 34 g (0.25 mol) of p-nitroaniline (Expt 6.68) and proceed exactly as above to the point where all the suspension of p-nitrobenzenediazonium fluoroborate has been added. Filter the reaction mixture with suction, wash the residue well with water, twice with 25 ml of 5 per cent sodium hydroxide solution and finally with water. Dry the solid at 100-110°C, powder it and extract it with four 150ml portions of boiling toluene. Remove the toluene with a rotary evaporator and recrystallise the residue from about 120 ml of boiling glacial acetic acid. The yield of p-dinitrobenzene (reddish-yellow crystals), m.p. 173 °C, is 30g (71.5%). Further recrystallisation from ethanol affords pale yellow crystals of the same m.p. The p.m.r. spectrum is noted above. 

Semer, R. and Reddy, K.R., Mechanisms controlling toluene removal from saturated soils during in-situ air sparging, /. Haz. Mat., 57, 209-230, 1998. 

In a 30-liter reactor, reflux 12.5 kg of (2S,3aS,7aS)-2-carboxyperhydroindole, 50 kg of para-toluenesulfonic acid and 14.2 kg of benzyl alcohol and 38.4 kg of toluene, removing the water formed with the aid of a continuous separator. When no more water separates out, cool, filter off the precipitate of para-toluenesulfonate of the benzyl ester of (2S,3aS,7aS)-2-carboxyoctahydroindole formed, and dry. Yield 91.3%. 

Refluxing in toluene removes the water as an azeotrope (see p. 347), but, in fact, the aminal forms so readily that, if you do this reaction in cold dichloromethane (in which water is insoluble), the solution becomes cloudy as droplets of water are produced ... 

A solution of 55 g. (0.33 mole) of 4-aminobiphenyl in 500 ml. of toluene treated as above, and the toluene removed by distillation, gives p-isocyanobiphenyl. The product is recrystallized from petroleum ether (b.p. 40-60°) to give 58 g. (91%) of product. (Cf. preparation of o-isocyanobiphenyl, p. 186.)... 

The 1-adamantyl (1-Ada) esters exhibit increased acid stability if compared to the tert-butyl esters.These amino acid esters are prepared by reaction of the amino acid tosylates with adamantan-l-ol and dimethyl sulfite in boiling toluene. Removal of the adamantyl ester is effected by neat TFA within 1 hour or TFAyCH2Cl2 (1-2) within 15 hours. N-Terminal Boc groups are selectively cleaved with 4 M HCl in anhydrous dioxane (rt, 25 noin) in the presence of the 1-adamantyl ester. 

Industrial methods of mono-nitration of benzene and toluene Removal of phenolic by-produets Periodic nitration Continuous nitration... 

In an attempt to reduce the overall epichlorohydrin hydrolysis the effect of removal of this component from the reaction system was investigated. A sample of the above reaction mixture was removed after the initial treatment with sodium hydroxide/sodium carbonate solution and the excess epichlorohydrin and toluene removed by vacuum distillation. 

The volume of the reaction mixture was kept constant by the addition of fresh toluene. The reaction mixture was filtered and the toluene removed under reduced pressure to give 0.90g of yellow solid, mp 65-70°C. Infrared and mass spectroscopy as well as thin layer chromatography revealed this to be almost exclusively starting material. 

Note The free amino acid can be obtained by an alternative aqueous work up. Instead of adding methanol and acetyl chloride (part 2 above), the reaction was filtered and the toluene removed in a rotary evaporator. Dilute hydrochloric acid was added to the residue and the mixture was refluxed overnight. Extraction of by-products with dichloromethane and evaporation to dryness of the aqueous phase gave the desired free amino acid. 

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