Toluene boiling-point

Haag (25) has examined the kinetics of toluene isopropylation and ethylation in the presence of REY catalyst. At 1 atm (total pressure) in the liquid phase, toluene alkylation with propylene is uncontrollably fast near 25°C, and decreases in rate with increasing temperature up to the toluene boiling point (110°C) because of decreasing partial pressure... 

To 30 grammes of freshly distilled toluene (boiling-point no0) contained in a wide-necked vessel (an extract of beef jar is convenient) cooled with water, add, not too quickly, 45 grammes of pulverised, freshly prepared aluminium chloride and 5 grammes pure cuprous chloride (see page 355). The vessel is closed by a three-hole cork in the middle hole is inserted a glass tube which carries a stirrer (paddle wheel of glass) the other holes are used for the inlet and outlet tubes (Fig. 75). 

Figure 12-3. Benzene-toluene boiling point curve. (Reproduced with permission from reference 8. Copyright 1997, American Chemical Society.)...

Solubility in toluene Boiling point Appearance Toxicity... 

BTX A mixture of low boiling point aromatics, i.e. benzene, toluene and xylenes. 

It follows that liquids of high boiling point should not be distilled from drying agent systems which have appreciable vapour pressures. An extreme case of this action is the dehydration of oxalic acid dihydrate by distillation over toluene or over carbon tetrachloride. 

Other mixtures which may be employed are carbon tetrachloride (b.p. 77°) and toluene (b.p. 110-111°) chloroform (b.p. 61°) and toluene methyl alcohol (b.p. 65°) and water (b.p. 100°). The last example is of interest because almost pure methyl alcohol may be isolated no constant boiling point mixture (or azeotropic mixture) is formed (compare ethyl alcohol and water, Sections 1,4 and 1,5). Attention is directed to the poisonous character of methyl alcohol the vapour should therefore not be inhaled. 

In the absence of catalysts, toluene when treated with chlorine (or bromine) at the boiling point, preferably with exposure to sunlight or other bright light source, undergoes halogenation in the side chain. The entrance of the first chlorine atom, for example, proceeds at a much faster rate than the entrance of the second chlorine atom so that in practice the major portion of the toluene is converted into benzyl chloride before appreciable chlorination of benzyl chloride occurs ... 

Because tetrahydrofurfuryl alcohol is virtuaHy colorless, it is used in lacquer formulations for aH colors as weU as water-white clear products. More speciftcaHy, tetrahydrofurfuryl alcohol is a wetting dispersant for most pigments. It has a high boiling point, high toluene dilution ratio, and good miscibility with oils, eg, linseed and soya, and is an exceUent solvent for a wide range of resins. 

Methylphenol. y -Cresol is produced synthetically from toluene. Toluene is chlorinated and the resulting chlorotoluene is hydrolyzed to a mixture of methylphenols. Purification by distillation gives a mixture of 3-methylphenol and 4-methylphenol since they have nearly identical boiling points. Reaction of this mixture with isobutylene under acid catalysis forms 2,6-di-/ f2 -butyl-4-methylphenol and 2,4-di-/ f2 -butyl-5-methylphenol, which can then be separated by fractional distillation and debutylated to give the corresponding 3- and 4-methylphenols. A mixture of 3- and 4-methylphenols is also derived from petroleum cmde and coal tars. 

Toluene is commonly used. It can be dried by molecular sieves or direct distillation from calcium hydride into the reaction flask. Solvent stored over calcium hydride for several days is usually sufficiently dry to decant directly into the reaction flask, but distillation gives more consistent results. Any solvent with a boiling point sufficiently high to melt sodium is satisfactory. The submitters have also used methyl-cyclohexane and xylene in acyloin condensations. After the sodium is dispersed, the high-boiling solvent can be removed and replaced with anhydrous ether (as noted by the submitters) or can be retained and used in combination with ether (checkers). 

The dehydrogenation reaction produces crude styrene which consists of approximately 37.0% styrene, 61% ethylbenzene and about 2% of aromatic hydrocarbon such as benzene and toluene with some tarry matter. The purification of the styrene is made rather difficult by the fact that the boiling point of styrene (145.2°C) is only 9°C higher than that of ethylbenzene and because of the strong tendency of styrene to polymerise at elevated temperatures. To achieve a successful distillation it is therefore necessary to provide suitable inhibitors for the styrene, to distil under a partial vacuum and to make use of specially designed distillation columns. 

In extractive distillation, the compounds which it is desired to separate are distilled in the presence of a solvent. This solvent, by reason of its greater affinity for one of the compounds, causes the other material present to exhibit an abnormally high vapor pressure which permits its removal from the system. For example, adding phenol to a mixture of toluene and close-boiling paraffins and naphthenes causes the toluene to behave as if it boiled as much as 40 °F above its normal boiling point. 

Preparation of l9-Norandrost-A-ene-3, l-dionef A solution of 1.1 g of 10y5-cyano-19-norandrost-5-ene-3,17-dione bis-ethylene ketal in a mixture of 15 ml of ethanol and 15 ml of toluene is carefully added to a vigorously stirred suspension of 10 g of sodium in 150 ml of boiling toluene. The addition is regulated to maintain the reaction mixture at the boiling point of the solvent. Another 40 ml of anhydrous ethanol is then added at the same rate. The solution is cooled and the excess of sodium is decomposed by addition of 95% ethanol. The reaction mixture is then diluted with water, the toluene layer separated and the aqueous phase extracted twice with ether. The organic solution is washed with water, dried and evaporated to yield 1 g of an amorphous mixture of the bis-ethylene ketals of 19- norahd-rost-5- and -5(10)-ene-3,17-dione (Note 1). 

Trichloro- and dichloromethane, ether, dioxane, benzene, toluene, chlorobenzene, acetonitrile, or even pyridine itself has been employed to carry out the one-pot syntheses. Tliese solvents allow straightforward preparation of the salts. The temperature range between 0° and 20°C is usually employed and the salts formed are sufficiently soluble. In the case of slow reactions, selection of a solvent with a higher boiling point is prohtable since thermal instability of the A -(l-haloalkyl)heteroarylium halides has not been reported. Addition of water or an aqueous solution of sodium acetate does not cause a rapid decomposition of the salts so that this constitutes a useful step in the optimization of some procedures. 

Another issue important to the success of this chiral titanium reagent 31 was the discovery of a marked solvent effect. When the fumaric acid derivative is reacted with isoprene in the presence of 10 mol% of the titanium reagent 31 in toluene, poor optical purity results (36-68% ee). Interestingly the optical purity of the adduct greatly increased in the order benzene, toluene, xylenes, and mesitylene, with 92% ee obtained in the last. Mesitylene is difficult to remove, because of its high boiling point, and other solvents were screened in detail. As a result, the mixed solvent system toluene petroleum ether (1 1) was discovered to be very effective. 

The mixture is then slowly heated to the boiling point of toluene and kept boiling for one hour under reflux. After the mixture has been allowed to cool the sodium chloride which precipitates is separated by extraction with water. The solution of toluene is then extracted with dilute hydrochloric acid. From the hydrochloric acid extract the basic substance is separated in the form of an oil by means of caustic soda solution and is introduced into ether. The ethereal solution Is dried with the aid of potassium carbonate and then distilled. 

A solution of 5-(3-toluene-p-sulfonvloxvpropvl)dibenzazepine (9.2 g) and 1-(2-hvdroxy-ethyDpiperazine (8.6 g) in anhydrous toluene (50 cc) is heated at boiling point under reflux for 4 hours. 

Sodium methylete is mede by dropping 11.7 g of sodium strips into 199 ml of absolute methanol in a 1-liter three-necked flask. 93.9 g of o-benzylphenol ere dissolved in 200 ml of dry toluene end added to the sodium methylete solution. The solution is distilled until the boiling point of toluene is reached. At the end of the distillation, enough toluene is added to restore the original volume of solvent. 

Removal of diluent by an extraction process To obtain the final stable macroporous structure, the liquid organic diluents and the linear polymer are removed from the crosslinked structure by extraction with a good solvent for the inert diluents and particularly for the linear polymer. Toluene or methylene chloride are usually preferred for the removal of linear polystyrene from the divinylbenzene crosslinked macroporous polystyrene particles [125,128]. The extraction is carried out within a Soxhelet apparatus at the boiling point of the selected solvent over a period usually more than 24 h. 

Example 8-5 Boiling Point Curve and Equilibriiun Diagram for Benzene-Toluene Mixture... 

Figure 8-18. Boiling point diagram for Example 8-5. Benzene-toluene, total pressure = 760 mm Hg. Used by permission of Robinson Gilliland.

Figure 8-20. Boiling point diagram for benzene-toluene mixture using K values, total pressure 760 mm Hg for Example 8-6.

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