Ethanol—continued solubility

The phase regions for micellar solutions and lyotropic liquid crystals form a complicated pattern in water/amphlphile/hydrocarbon systems. The present treatment emphasizes the fact that they may be considered as parts of a continuous solubility region similar to the one for water/short chain amphiphilic systems such as water/ethanol/ethyl acetate. 

It is essential to realize that any thermodynamic evaluation of this solubility "maximum" with standard reference conditions in the form of the three pure components in liquid form is a futile exercise. The complete phase diagram. Fig. 2, shows the "maximum" of the solubility area to mark only a change in the structure of the phase in equilibrium with the solubility region. The maximum of the solubility is a reflection of the fact that the water as equilibrium body is replaced by a lamellar liquid crystalline phase. Since this phase.transition obviously is more. related to packing constraints — than enthalpy of formation — a view of the different phases as one continuous region such as in the short chain compounds water/ethanol/ethyl acetate. Fig. 3, is realistic. The three phases in the complete diagram. Fig. 2, may be perceived as a continuous solubility area with different packing conditions in different parts (Fig. 4). 

To produce highly purified phosphatidylcholine there are two industrial processes batch and continuous. In the batch process for producing phosphatidylcholine fractions with 70—96% PC (Pig. 4) (14,15) deoiled lecithin is blended at 30°C with 30 wt % ethanol, 90 vol %, eventually in the presence of a solubiHzer (for example, mono-, di-, or triglycerides). The ethanol-insoluble fraction is separated and dried. The ethanol-soluble fraction is mixed with aluminum oxide 1 1 and stirred for approximately one hour. After separation, the phosphatidylcholine fraction is concentrated, dried, and packed. 

In the continuous process for producing phosphatidylcholine fractions with 70—96% PC at a capacity of 600 t/yr (Pig. 5) (16), lecithin is continuously extracted with ethanol at 80°C. After separation the ethanol-insoluble fraction is separated. The ethanol-soluble fraction mns into a chromatography column and is eluted with ethanol at 100°C. The phosphatidylcholine solution is concentrated and dried. The pure phosphatidylcholine is separated as dry sticky material. This material can be granulated (17). 

In about 5-10 minutes a clear solution resulted, whereupon slow crystallization occurred and the temperature rose to about 6°-7°C. The crystallization was permitted to continue overnight at 5°C, and the very fine precipitate was then isolated by centrifugation and in the centrifuge washed with water, ethanol, and ether, yielding the dihydrate of DL-seryl-(2,3,4-trihydroxy-benzylidene) hydrazide hydrochloride, which melted at 134°-136°C and was poorly soluble in cold water, but very readily dissolved in hot water. The condensation was also effected in absolute ethanol yielding the anhydrous form of the hydrazone, which melted at 225°-228°C. 

Thereupon xylene is introduced again in vacuo at a temperature of 100°-105°C whereby all the methanol and the ethanol formed during re-esterification evaporates. The re-esterif-ication is continued under these conditions until a specimen of the reaction mass is clearly soluble in cold water, which occurs after about 2-3 hours. There is now obtained in almost quantitative yield the ester of the formula... 

Washing of the precipitate may often be effected with hot or cold water (according to the solubility of the metal oxinate ) and is continued until the filtrates become colourless. The use of ethanol is permissible if it is known to have no effect upon the precipitate. 

The enzyme p-ethylphenol methylene hydroxylase (EPMH), which is very similar to PCMH, can also be obtained from a special Pseudomonas putida strain. This enzyme catalyzes the oxidation of p-alkylphenols with alkyl chains from C2 to C8 to the optically active p-hydroxybenzylic alcohols. We used this enzyme in the same way as PCMH for continuous electroenzymatie oxidation of p-ethylphenol in the electrochemical enzyme membrane reactor with PEG-ferrocene 3 (MW 20 000) as high molecular weight water soluble mediator. During a five day experiment using a 16 mM concentration of p-ethylphenol, we obtained a turnover of the starting material of more than 90% to yield the (f )-l-(4 -hydroxyphenyl)ethanol with 93% optical purity and 99% enantiomeric excess (glc at a j -CD-phase) (Figure 14). The (S)-enantiomer was obtained by electroenzymatie oxidation using PCMH as production enzyme. 

Concentrates are made by extracting water-soluble sugars and other compounds from defatted meals or flours. This is typically a secondary extraction, using acidic ethanol-water in a chain-type or basket-type continuous extractor for processing flakes, or acidic water extraction of flour in vats, followed by spray-drying (8). Acidic polar solvents are used at or near the isoelectric point of the protein to minimize its solubility and loss. The reextracted flakes may then be ground into a flour. Concentrates are more bland than defatted flours, but still contain the fiber components of the kernel. After extraction with acidic ethanol or water, concentrates... 

Concurrent with acetic anhydride formation is the reduction of the metal-acyl species selectively to acetaldehyde. Unlike many other soluble metal catalysts (e.g. Co, Ru), no further reduction of the aldehyde to ethanol occurs. The mechanism of acetaldehyde formation in this process is likely identical to the conversion of alkyl halides to aldehydes with one additional carbon catalyzed by palladium (equation 14) (18). This reaction occurs with CO/H2 utilizing Pd(PPh )2Cl2 as a catalyst precursor. The suggested catalytic species is (PPh3)2 Pd(CO) (18). This reaction is likely occurring in the reductive carbonylation of methyl acetate, with methyl iodide (i.e. RX) being continuously generated. 

The composite materials have been used to form selective membranes for the separation of liquid mixtures [181]. The membranes should consist of a polymer which is soluble in the liquid components) to be separated, as the dispersed phase-derived polymer, and a continuous phase-derived polymer which is insoluble in all components of the liquid mixture. Thus, membranes consisting of polystyrene in polyacrylamide will separate toluene from cyclohexane, and those comprising polyacrylamide in crosslinked polystyrene can be used for water removal from ethanol. Due to the very thin films of polymer which separate the polyhedral dispersed phase cells, the permeation rates, which are measured by pervaporation, are relatively high. 

The principle of extraction is based on a physical chemical phenomenon known as partitioning. If two fluids, one of which contains a solute that is soluble in both, come in contact with one another, the solute will migrate from the original fluid into the other fluid. The extent (but not the rate) to which it will migrate is governed by the relative solubilities of the fluids. See Table 4.2. If the solute is equally soluble in both fluids, half will continue to migrate until the concentrations in both fluids are the same. If the solute is much more soluble in one fluid or the other, the fluid in which the solute is most soluble will accumulate most of the solute. For instance, if ethanol is dissolved in water and contacted with a solvent, the amount of ethanol removed from the water depends on the solvent. 

The analysis of the reaction serum (the continuous phase without polymer particles) at the end of polymerization led to the conclusion that the molecular weight of the soluble oligomers of styrene and PEO macromonomer varied from 200 to 1100 g mol-1. This indicates that the critical degree of polymerization for precipitation of oligomers in this medium is more than ten styrene units and only one macromonomer unit per copolymer chain. Several reasons for the low molecular weight of the soluble copolymers were proposed, such as the thermodynamic repulsion (or compatibility) between the PEO chain of the macromonomer and the polystyrene macroradical, the occurrence of enhanced termination caused by high radical concentration, and, to a lower extent, a transfer reaction to ethanol [75]. 

Note. (1) Alternatively, the following procedure for isolating the diol may be used. Dilute the partly cooled mixture with 250 ml of water, transfer to a distilling flask, and distil from an oil bath until the temperature reaches 95 °C. Transfer the hot residue to an apparatus for continuous extraction with ether (e.g. Fig. 2.93). The extraction is a slow process (36-48 hours) as the diol is not very soluble in ether. Distil off the ether and, after removal of the water and ethanol, distil the diol under reduced pressure. 

Acrylic emulsion - The emulsion consisted of suspended crosslinked (gel) particles that are not water-soluble and form a film upon evaporation of the aqueous phase. However, the water did not evaporate quickly enough to form a continuous film on agar because agar is 95% water, and it continuously provided moisture that prevented film formation. The result was a porous barrier, but a continuous film was later obtained by dissolving dried emulsion solids in ethanol. 

A solution of 12.6 g. of pure a-methyl-D-glucopyranoside (XXVII) in distilled water is added to 260 cc. of 0.54 M aqueous periodic acid solution (2.1 molecular equivalents). The solution, after being diluted with water to 500 cc., is kept at 20-25° for about twenty-four hours. If desired, the excess periodic acid can be determined by the arsenite method. The rotation of the reaction solution should correspond to [a]i> = +121° calculated for the dialdehyde XXVIII. The solution is neutralized to phenolphthalein with hot strontium hydroxide solution with care to avoid any excess. The precipitate of strontium iodate and strontium periodate is filtered and washed with cold water. After the addition of 1 g. <5f strontium carbonate, the solution is concentrated in vacuum with the water bath at 50° to a volume of about 50 cc., filtered to Temove strontium carbonate, and the concentration (bath, 40°) continued to dryness. The residue is extracted six times with 25-cc. portions of cold absolute ethanol, which separates the dialdehyde completely from slightly soluble strontium salts, as shown by the lack of optical activity of an aqueous solution of these salts. The dialdehyde XXVIII is recovered from the ethanol solution as a colorless syrup in quantitative yield by distillation of the solvent in vacuum with the bath at 40-45°. 

Preparation from Carbohydrazide. One hundred seventeen grams of carbohydrazide (1.3 mols) and 108 ml. of 12 M hydrochloric acid (1.3 mols) are" mixed in a 400-ml. beaker equipped with a mechanical stirrer and a 360° thermometer. The mixture is heated slowly on a hot plate with constant stirring. At first, there is vigorous effervescence, which may cause spattering, but this gradually subsides as evaporation continues. The temperature rises to about 215° and remains there for approximately an hour. Heating is stopped when the temperature rises above 220°. The over-all time of reaction is 4 hours. To the cooled melt, 125 ml. of water is added, and the mixture is heated to effect solution of soluble by-products (principally hydrazine hydrochloride). After the solution has cooled to room temperature, the urazine is filtered and washed with water, ethanol, and ether. The yield of dry product is 55 g. (73%)- The product melts with decomposition at 271 to 272°. 

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