Mixing of ethanol and

The direction of a deviation from Raoult s law can be correlated with the enthalpy of mixing, AHmix, the enthalpy difference between the mixture and the unmixed components. The enthalpy of mixing of ethanol and benzene is positive—the mixing process is endothermic—and this mixture also shows a positive deviation from Raoult s law. The enthalpy of mixing of acetone and chloroform is negative—the mixing process is exothermic—and this mixture shows a negative deviation from Raoult s law. 

MiniLab 1 Is the mixing of ethanol and water an exothermic or an endothermic process Is it a chemical or physical change ... 

Which of the following is not accompanied by an increase in the entropy of the system (a) mixing of two gases at the same temperature and pressure, (b) mixing of ethanol and water, (c) discharging a battery, (d) expansion of a gas followed by compression to its original temperature, pressure, and volume. 

It is very important to dewax the sisal fiber to improve its properties. One of the researchers studied the dewaxing of sisal fiber with a 1 2 mix of ethanol and... 

If cold saturated ethanolic solutions of the recrystallised tetrahydrocarbazole and of picric acid are mixed and stirred, the chocolate-brown picrate of the carbazole slowly crystallises. After it has been filtered off at the pump, washed with a small quantity of ethanol, and dried, it has m.p. 145-146°. 

Coelenterazine (A) is oxidized into dehydrocoelenterazine (D) by MnC>2 in a mixed solvent of ethanol and ether (Inoue et al., 1977b). Dehydrocoelenterazine (C26H19O3N3) can be obtained as dark red crystals. It does not have the capability of chemiluminescence. The ultraviolet absorption spectrum (Fig. 5.6) shows its absorption maxima at 425 nm (e 24,400) and 536 nm (g 12,600) in ethanol. An addition of NaOH significantly increases the 536 nm peak at the expense of the 425 nm peak. Dehydrocoelenterazine can take a tautomeric structure of quinone type (not shown), in which the phenolic proton on the 2-substituent is shifted onto the N(7) of the imida-zopyrazinone ring. Dehydrocoelenterazine can be readily reduced to... 

Sample Preparation. Liquid crystalline phases, i.e. cubic and lamellar phases, were prepared by weighing the components in stoppered test tubes or into glass ampoules (which were flame-sealed). Water soluble substances were added to the system as water solutions. The hydrophobic substances were dissolved in ethanol together with MO, and the ethanol was then removed under reduced pressure. The mixing of water and MO solutions were made at about 40 C, by adding the MO solution dropwise. The samples for the in vivo study were made under aseptic conditions. The tubes and ampoules were allowed to equilibrate for typically five days in the dark at room temperature. The phases formed were examined by visual inspection using crossed polarizers. The compositions for all the samples used in this work are given in Tables II and III. 

In a 3-1. round-bottomed flask equipped with a reflux condenser are placed 582 g. (2.5 moles) of N-tricarboxylic ester (p. 60) and 800 g. (6.7 moles) of 42% hydrazine hydrate (Note 1). The flask is shaken by hand to mix the two layers. After a short time, reaction begins with considerable evolution of heat, and all the N-tricarboxylic ester goes into solution (Note 2). After the reaction subsides, the solution is heated for 1 hour on a steam bath and then evaporated under reduced pressure until the mixture becomes a thick slurry of diaminobiuret crystals (Note 3). The mixture is cooled, 2 1. of 95% ethanol is added, and the diaminobiuret which has crystallized is filtered, washed with 250 ml. of ethanol, and dried. The substance melts at 205° with decomposition. The yield is 115-125 g. (69-75%). 

High resolution transmission electron microscopy (HRTEM) micrographies were performed with a JEOL JEM-3010 microscope operating at 300 kV (Cs= 0.6 mm, point resolution 1.7 A). Images were recorded with CCD camera (MultiScan model 794, Gatan, 1024 x 1024 pixels, pixel size 24 x 24 pm2). The powder samples were mixed in ethanol and then ultrasonicated for 10 min. A drop of the wet sample was placed on a copper grid and then allowed to dry for 10 min before TEM analysis. 

The 50% v/v EtOH-H20 in Wepster s work is made by taking V cm3 of ethanol and making up to 2V cm3 with water. It is thus different from the 50% EtOH-H20 mentioned in Table 3, which is made by mixing equal volumes of ethanol and water. 

Microcrystallin cellulose triacetate (MCTA) has also been employed in the TLC analysis of flavanones. Plates were home-made by mixing 3 g of silica with 9 g of MCTA in 35 ml of ethanol and the suspension was spread on to 20 X 10 cm plates. A considerable number... 

Make a mixture of 43 g of ethyl a-keto-y-dimethylamino-butyrate p-acetylphenylhydrazone and 430 g of polyphosphoric acid and heat slowly with stirring. At 60-65° an exothermic reaction should be noticed with foaming (this will require you to have chosen a larger than normal reaction vessel). Raise the temp (gradually) to 102-109° and hold for 2 hours. Cool to 70° and pour the viscous solution into 700 ml of ice-water. Mix into complete solution with good stirring, make basic at a low temp, and extract with three 400 ml portions of chloroform. Combine the extracts and dry over sodium sulfate, then evaporate in vacuo. Add the residue to 150 ml of ethanol and mix into complete solution. Treat with ethanolic HCl and allow to stand overnight (12 hours). Filter off the precipitated salt and recrystallize from 95% ethanol. Yield 37%, mp 211-214°. 

In addition to hydrogen as a fuel, methanol or ethanol can be directly converted into electricity in a DAFC, the great progress of which resulted from the use of a proton exchange membrane acting both as an electrolyte (instead of the aqueous electrolytes previously used) and as a separator preventing the mixing of fuel and oxidant. A DAFC can work at moderate temperatures (30-50 °C) for portable applications, but now the tendency is to look for new membranes that are less permeable to alcohol and... 

FeCla -6H20 (0.02 mol, 5.4 g) is dissolved in 50 mL of ethanol, and this solution is added dropwise to 30 mL of an ethanolic solution of bis(3-salicylideneamino-propyl)methylamine (0.022 mol, 7.77 g) contained in a 150-mL round-bottomed flask. Triethylamine (0.044 mol, 6.2 mL) mixed with 10 mL of ethanol is added dropwise to the preceding solution. The mixture is heated at 60°C for 20 min. The black precipitate formed is filtered with a sintered glass, washed 5 times with 10-mL aliquots of absolute ethanol, and dried under vacuum overnight. Yield 6.6 g, 75%. 

In a 3-1. round-bottomed flask fitted with a mechanical stirrer and a reflux condenser is placed 2.0 1. of anhydrous ethanol. To this is added 11.5 g. (0.5 g.-atom) of sodium cut into small pieces. When the sodium is completely dissolved, 23.6 g. (21.0 ml., 0.25 mole) of 1,2-ethanedithiol2 is added, followed by 47.0 g. (21.7 ml., 0.25 mole) of ethylene dibromide. The mixture is stirred and refluxed for 4 hours, cooled, and filtered to remove some sodium bromide mixed with polyethylene sulfide. The solid is washed with 100 ml. of ethanol, and the combined filtrates are distilled with stirring. When bumping becomes troublesome, as it generally does when 1.3-1.5 1. of distillate has been collected, the hot reaction mixture is filtered to remove sodium bromide, and the sodium bromide is washed with 100 ml. of hot ethanol. 

Figure 13.23. Examples of vapor-liquid equilibria in presence of solvents, (a) Mixture of-octane and toluene in the presence of phenol, (b) Mixtures of chloroform and acetone in the presence of methylisobutylketone. The mole fraction of solvent is indicated, (c) Mixture of ethanol and water (a) without additive (b) with 10gCaCl2 in 100 mL of mix. (d) Mixture of acetone and methanol (a) in 2.3Af CaCl2 ip) salt-free, (e) Effect of solvent concentration on the activity coefficients and relative volatility of an equimolal mixture of acetone and water (Carlson and Stewart, in Weissbergers Technique of Organic Chemistry IV, Distillation, 1965). (f) Relative volatilities in the presence of acetonitrile. Compositions of hydrocarbons in liquid phase on solvent-free basis (1) 0.76 isopentane + 0.24 isoprene (2) 0.24 iC5 + 0.76 IP (3) 0.5 iC5 + 0.5 2-methylbutene-2 (4) 0.25-0.76 2MB2 + 0.75-0.24 IP [Ogorodnikov et al., Zh. Prikl. Kh. 34, 1096-1102 (1961)].

The 50% ethanol-water of Hoefnagel and Wepster was made by mixing V dm3 of ethanol with water and making up to 2V dm3. It contains 22.4 mol% ethanol. It must be carefully distinguished from the 50% ethanol-water solvent used by many other authors, which is obtained by mixing equal volumes of ethanol and water. It contains 23.6 mol% ethanol. 

Method 2 (p-nitrobenzyl ester). To the residue are added 3 ml of ethanol and a 20-fold excess of 1 -p-nitrobenzyl-3-p-tolyltriazene [43]. The contents are mixed, loosely covered and heated at a gentle reflux for 1 h. The solution is cooled and an aliquot portion is subjected to chromatography. The derivatives are non-polar compared to the reagent and the parent fatty acid, and may be separated on silica gel with non-polar solvents such as hexane-diethyl ether. HPLC should also be useful with a system similar to that used for the benzyl esters. The limits of detection of the p-nitrobenzyl derivatives should be significantly lower than those of the benzyl esters. 

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