Chloroform, boiling point

A thin film for FTIR imaging can be prepared by solvent casting. Solvent casting requires a solvent that dissolves the sample preferably at room temperature, which can be easily removed (high vapor pressure) without formation of bubbles in the sample film. Solvents such as chloroform (boiling point (bp.) 61.2°C), acetone... 

Chloroform (boiling point 61.7°C, melting point -63.5°C, density 1.4832) is produced by the chlorination of methylene chloride, which in turn is made by the chlorination of methyl chloride and methane. 

Solubility Soluble in N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, methanol, chloroform Boiling Point (Calcd.) 580.4 50.0 °C, pressure 760 Torr... 

Many liquid mixtures exhibit a minimum boiling point (e.g. methanol and chloroform -propanol and water) whilst others show a... 

Selection of solvents. The choice of solvent will naturally depend in the first place upon the solubility relations of the substance. If this is already in solution, for example, as an extract, it is usually evaporated to dryness under reduced pressure and then dissolved in a suitable medium the solution must be dilute since crystallisation in the column must be avoided. The solvents generally employed possess boiling points between 40° and 85°. The most widely used medium is light petroleum (b.p. not above 80°) others are cycZohexane, carbon disulphide, benzene, chloroform, carbon tetrachloride, methylene chloride, ethyl acetate, ethyl alcohol, acetone, ether and acetic acid. 

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. 

A. Maleic acid. Assemble the apparatus shown in Fig. Ill, 28, 1. Place 45 g. of dry mahc acid in the 200-250 ml. distilling flask and cautiously add 63 g. (57 ml.) of pure acetyl chloride. Warm the flask gently on a water bath to start the reaction, which then proceeds exothermically. Hydrogen chloride is evolved and the malic acid passes into solution. When the evolution of gas subsides, heat the flask on a water bath for 1-2 hours. Rearrange the apparatus and distil. A fraction of low boiling point passes over first and the temperature rises rapidly to 190° at this point run out the water from the condenser. Continue the distillation and collect the maleic anhydride at 195-200°. Recrystallise the crude maleic anhydride from chloroform (compare Section 111,93) 22 g. of pure maleic anhydride, m.p. 54°, are obtained. 

By-products from EDC pyrolysis typically include acetjiene, ethylene, methyl chloride, ethyl chloride, 1,3-butadiene, vinylacetylene, benzene, chloroprene, vinyUdene chloride, 1,1-dichloroethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane [71-55-6] and other chlorinated hydrocarbons (78). Most of these impurities remain with the unconverted EDC, and are subsequendy removed in EDC purification as light and heavy ends. The lightest compounds, ethylene and acetylene, are taken off with the HCl and end up in the oxychlorination reactor feed. The acetylene can be selectively hydrogenated to ethylene. The compounds that have boiling points near that of vinyl chloride, ie, methyl chloride and 1,3-butadiene, will codistiU with the vinyl chloride product. Chlorine or carbon tetrachloride addition to the pyrolysis reactor feed has been used to suppress methyl chloride formation, whereas 1,3-butadiene, which interferes with PVC polymerization, can be removed by treatment with chlorine or HCl, or by selective hydrogenation. 

At 225—275°C, bromination of the vapor yields bromochloromethanes CCl Br, CCl2Br2, and CClBr. Chloroform reacts with aluminum bromide to form bromoform, CHBr. Chloroform cannot be direcdy fluorinated with elementary flourine fluoroform, CHF, is produced from chloroform by reaction with hydrogen fluoride in the presence of a metallic fluoride catalyst (8). It is also a coproduct of monochlorodifluoromethane from the HF—CHCl reaction over antimony chlorofluoride. Iodine gives a characteristic purple solution in chloroform but does not react even at the boiling point. Iodoform, CHI, may be produced from chloroform by reaction with ethyl iodide in the presence of aluminum chloride however, this is not the route normally used for its preparation. 

FIG. 13-12 Liq iiid boiling points and vapor condensation temperatures for maximum-boiling azeotrope mixtures of chloroform and acetone at 101.3 kPa (1 atm) total pressure. 

This example clearly shows good distribution because of a negative deviation from Raonlt s lawin the extract layer. The activity coefficient of acetone is less than 1.0 in the chloroform layer. However, there is another problem because acetone and chloroform reach a maximum-boiling-point azeotrope composition and cannot be separated completely by distillation at atmospheric pressure. 

Although less common, azeotropic mixtures are known which have higher boiling points than their components. These include water with most of the mineral acids (hydrofluoric, hydrochloric, hydrobromic, perchloric, nitric and sulfuric) and formic acid. Other examples are acetic acid-pyridine, acetone-chloroform, aniline-phenol, and chloroform-methyl acetate. 

Whilst the water is boiling steadily and not too violently, the substance is weighed. Chloroform, b.p. 61, or pure and dry ether, bp. 34-5° (see Prep. 3, p 59), may be used for the experiment, as their boiling-points he well below that of water. Before introducing the bottle and liquid, the apparatus must be tested to ascertain if the temperatur e is constant. As a rule hour s boiling suffices. Push in the rubber cork and note if within the next minute or two any bubbles csc.rije. If... 

By oxidation of d- and Z-pinene of high rotatory power, Barbier and Grignard obtained the optically active forms of pinonic acid. Z-pinene from French turpentine oil (boiling-point 155 to 157 , od - 37 2 157 to 160 , tto - 32 3°) was oxidised with permanganate. From the product of oxidation, which (after elimination of the volatile acids and of nopinic acid) boiled at 189 to 195 under 18 mm. pressure, Z-pinonic acid separated out in long crystalline needles, which, after recrystallisation from a mixture of ether and petroleum ether, melted at 67° to 69 . The acid was easily soluble in water and ether, fairly soluble in chloroform, and almost insoluble in petroleum ether. Its specific rotation is [a]o - 90-5 in chloroform solution. Oximation produced two oximes one, laevo-rotatory, melting-point 128 and the other, dextro-rotatory, melting-point 189° to 191°. 

The first step involves the preparation of 1 -(3-isobutoxy-2-chloro)propyl pyrrolidine as an intermediate. 345 ml of thionyl chloride dissolved in 345 ml of chloroform are added, drop by drop, to 275 g of 1 -(3-isobutoxy-2-hydroxy)propyl pyrrolidine dissolved in 350 ml of chloroform, while maintaining the temperature at approximately 45°C. The reaction mixture is heated to reflux until gas is no longer evolved. The chloroform and the excess of thionyl chloride are removed under reduced pressure. The residue is poured on to 400 g of crushed ice. The reaction mixture is rendered alkaline with soda and the resulting mixture is extracted twice with 250 ml of diethyl ether. The combined ethereal extracts are dried over anhydrous sodium sulfate. After evaporation of the solvent the residue is distilled under reduced pressure. 220 g of product are obtained having the following properties boiling point = 96°C/3 mm, n074 = 1.4575. 

A mixture of 24 g of 1,3-dimethyladamantane and BO ml of bromine was refluxed for 6 hours. The reaction product mixture was cooled, taken up in about 200 ml of chloroform, and poured onto ice. The excess bromine was removed by adding sodium hydrosulfite. The chloroform layer was separated from the aqueous layer, dried, concentrated in vacuo, and distilled at reduced pressure to yield 30.5 g of product having a boiling point of about 11B°C at 5-6 mm np = 1.5169-1.51B2. The product was identified by nuclear magnetic resonance (NMR) and elemental analyses as 1-bromo-3,5-dimethyladamantane. 

To a solution of 21 g of 1 (3 4 -methylenedioxybenzyl)-piperazine in solution in 300 cc of anhydrous xylene there were added 28 g of anhydrous potassium carbonate and then 11.3 g of 2boiling point (130 C). After this time, the mixture was cooled and extracted several times with 10% hydrochloric acid. The acid solution obtained was washed with ether and then rendered alkaline with potassium carbonate the oily product which was separated was extracted with chloroform and this, after drying with potassium carbonate and evaporation, gave an oily residue weighing 20 g. By dissolution in boiling ethanol and crystallization, 15 g of crystals melting at 96°C were recovered. 

The requisite intermediate, ethyl 4-dimethylaminocyclohexylcarboxylate is prepared as follows 33 g of ethyl p-aminobenzoate dissolved in 300 cc of absolute ethanol containing 16.B cc of concentrated hydrochloric acid is hydrogenated at 50 pounds hydrogen pressure in the presence of 2 g of platinum oxide. The theoretical quantity of hydrogen is absorbed in several hours, the catalyst removed by filtration and the filtrate concentrated to dryness in vacuo. The residue Is dissolved in water, made alkaline with ammonium hydroxide and extracted with chloroform. After removal of the solvent, the residual oil is distilled to yield ethyl 4-aminocyclohexylcarboxylate, boiling point 114°C to 117°C/10 mm. 

A mixture of 49 g of this ester compound, 76 g of 9B% formic acid and 6B ml of formalin solution is heated under reflux for B hours. The solvents are then removed in vacuo on the steam bath, the residue dissolved in water, made alkaline with ammonium hydroxide and extracted with chloroform. Removal of the solvent and distillation in vacuo yieids ethyl 4-di-methylaminocyclohexylcarboxylate, boiling point 122°C to 125°C/10 mm. 

Trimethylamine oxide is normally available as a hydrate, and for the present preparation it is necessary to convert it to its anhydrous form. A convenient way of doing this is as follows. A solution of 45.0 g. of trimethylamine oxide dihydrate (supplied by Beacon Chemicals) is dissolved in 300 ml. of warm dimethyl-formamide and placed in a three-necked flask set up for distillation. At atmospheric pressure the flask is heated and solvent distilled off until the boiling point reaches 152-153°. Then the pressure is reduced using a water aspirator, and the remainder of the solvent is distilled. At the end of the distillation the temperature of the bath is slowly raised to 120°. The residual anhydrous trimethylamine oxide (30 g.) can be dissolved in 100 ml. of chloroform and may remain in the same flask for use in the present preparation. 

It is difficult to estimate the magnitude of the error due to insufficiently low humidity when distillation methods are used with organic liquids such as toluene (6, 28), xylene (6, 28), or chloroform (12). With organic liquids essentially immiscible with water and of high boiling point the error is probably very small. When methanol is used as an extraction solvent, as in the Fischer reagent method, the amount of unextracted water is undoubtedly some function of the concentration of water in the alcohol, but the error might be small because of substitution of adsorbed water by adsorbed alcohol (23, 34). This seems to be borne out by experiments of Schroeder and Nair (31), who deliberately added water to the alcohol to form a 0.5% water solution and found that the results of their moisture determinations were essentially the same as with anhydrous methanol, which contained about 0.05% water. 

Satisfactory chloroform is obtained by washing 2 1. of commercial chloroform with two 100-ml. portions of 2N sodium carbonate solution and two 200-ml. portions of water and distilling it until no more water codistils and the boiling point is 61°. The material remaining in the distillation pot is used without distillation. 

Deviations from Raoult s law can make it impossible to separate liquids by distillation. The temperature-composition diagrams for mixtures of ethanol and benzene and of acetone and chloroform show why. A positive deviation from Raoult s law means that the attractive forces between solute and solvent are lower than those between the molecules of the pure components. As a result, the boiling point of the mixture is lower than that predicted by Raoult s law. For some pairs of components, the boiling point of the mixture is in fact lower than the boiling point of either constituent (Fig. 8.41). A mixture for which the lowest boiling temperature is below... 

Other anesthetics susceptible to abuse, such as ether and chloroform, have received far less attention, because they are considered to be less commonly abused substances. Nonetheless, when inhaled, ether and chloroform are also rapidly absorbed and distributed in the central nervous system (CNS), inducing a rapid euphoria. Ether and chloroform inhalation is facilitated by the fact that they have a low boiling point (i.e., approximately 34°C) (Delteil et al. 1974). 

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