Ethanol isolation

Van Duin van Lennep (Ref 6) prepd a water-sol compd exploding at 160—170° by treating the Pentanitrodimethylphenylene-diamine with ammonia (in water, methanol or ethanol), isolating the brown compd and treating it. (after recrystallization from methyl salicylate) with aq Na hydroxide... 

R.M. Black, K. Brewster, R.J. Clarke, J.L. Ham-brook, J.M. Harrison and D.J. Howells, Metabolism of thiodiglycol (2,2 -thiobis-ethanol) isolation and identification of urinary metabolites following intraperitoneal administration to rat, Xenobiotica, 23, 473-481 (1993). 

Higher inclusion ability of 68b for alcohols as compared to 68a is probably due to a similar steric factor (Table 5). Anyhow, refering to the above finding, efficient host compounds which have 2,4-dimethylphenyl groups (77 and 69) were designed for ethanol isolation. 

Ethanol isolation proceeds via distUlative processes. Owing to the formation of an ethanol/water azeotrope (95.5 mass% ethanol at 1 bar), the production of water-free ethanol requires the application of extractive distillation (typical entrainer benzene or cyclohexane, see Section 3.3.2.3). The isolation of water-free ethanol from fermentation is a relatively energy intense step. Even with a clever combination of several distillation columns working at different pressures, the energy input to produce 1 kg of bioethanol by fermentation is about 10 MJ (Baerns et al, 2006). In a few countries, where the production of bioethanol is particularly cheap (e.g., Brazil), there have also been attempts to convert bioethanol into chemicals in commercial scenarios. The production of ethylene from bioethanol is a potential option in this context. 

A basic alumina column eluted first with benzene and then with ethanol isolates the mutagenic components of the ether-soluble base fractions of synthetic crude oils into a fraction of about 25 wt% of the ether-soluble base. Further separation is achieved by eluting the ethanol isolate through a... 

Hydrolysis of />-Tolunitrile. As in the case of benzonitrile, alkaline h> drolysis is preferable to hydrolysis by 70% sulphuric acid. Boil a mixture of 5 g. of p-tolunitrile, 75 ml. of 10% aqueous sodium hydroxide solution and 15 ml. of ethanol under a reflux water-condenser. The ethanol is added partly to increase the speed of the hydrolysis, but in particular to prevent the nitrile (which volatilises in the steam) from actually crystallising in the condenser. The solution becomes clear after about i hour s heating, but the boiling should be continued for a total period of 1-5 hours to ensure complete hydrolysis. Then precipitate and isolate the p-toluic acid, CH3CgH4COOH, in precisely the same way as the benzoic acid in the above hydrolysis of benzonitrile. Yield 5 5 g. (almost theoretical). The p-toluic acid has m.p. 178°, and may be recrystallised from a mixture of equal volumes of water and rectified spirit. 

When the sodium derivative, which is used in ethanol it solution without intermediate isolation, is boiled with an alkyl halide, e.g., methyl iodide,... 

The experimental conditions for conducting the above reaction in the presence of dimethylformamide as a solvent are as follows. In a 250 ml. three-necked flask, equipped with a reflux condenser and a tantalum wire Hershberg-type stirrer, place 20 g. of o-chloronitrobenzene and 100 ml. of diinethylform-amide (dried over anhydrous calcium sulphate). Heat the solution to reflux and add 20 g. of activated copper bronze in one portion. Heat under reflux for 4 hours, add another 20 g. portion of copper powder, and continue refluxing for a second 4-hour period. Allow to cool, pour the reaction mixture into 2 litres of water, and filter with suction. Extract the solids with three 200 ml. portions of boiling ethanol alternatively, use 300 ml. of ethanol in a Soxhlet apparatus. Isolate the 2 2- dinitrodiphenyl from the alcoholic extracts as described above the 3ueld of product, m.p. 124-125°, is 11 - 5 g. 

After 5 hours the reaction is stopped and the flask cooled. The formyl-MDA can be isolated and hydrolyzed by any of the ways Strike just mentioned a few paragraphs back, but this method offers a third, very convenient way which should be tried. What the chemist does is forget about letting the flask and its contents cool. Instead, she removes the oil bath, places the flask back on the stirplate (distillation setup still attached), attaches a vacuum and distills off all the formamide. What remains is a dark, heavy formyl-MDA precipitate that is allowed to cool down while the chemist makes up a solution of 150g potassium hydroxide (KOH), 500mL ethanol and 125mL dH20. This solution is poured into the... 

Two moles of /3-alkoxyaicene can condense on each other by means of their a- and /3-carbon atoms. The resulting intermediate reacts on the anhydrobase by elimination of a molecule of ethanol resulting in a neocyanine formation (Schemes 59 and 60). Both monoanilino and bis-anilino derivatives resulting from the condensation of dimethylform-amide have been isolated. They are capable of furnishing various condensations on either ketomethylene or another reactive nucleus (Scheme 61). 

As actually carried out the mixed aldol condensation product 1 3 diphenyl 2 propen 1 one has been isolated in 85% yield on treating benzaldehyde with ace tophenone in an aqueous ethanol solution of sodium hydroxide at 15-30°C... 

In spite of their easy interconversion in solution a and p forms of carbohydrates are capable of independent existence and many have been isolated m pure form as crys talline solids When crystallized from ethanol d glucose yields a d glucopyranose mp 146°C [a]o +112 2° Crystallization from a water-ethanol mixture produces p d glucopyranose mp 148-155°C [aj +18 7° In the solid state the two forms do not mterconvert and are stable indefinitely Their structures have been unambiguously con firmed by X ray crystallography... 

A pepsin hydrolysate of flounder fish protein isolate has been used as the substrate (40% w/v) for plastein synthesis, using either pepsin at pH 5 or alpha chymotrypsin at pH 7, with an enzyme—substrate ratio of 1 100 w/v at 37°C for 24 h (151). The plastein yields for pepsin and alpha chymotrypsin after precipitation with ethanol were 46 and 40.5%, respectively. 

Iron hahdes react with haHde salts to afford anionic haHde complexes. Because kon(III) is a hard acid, the complexes that it forms are most stable with F and decrease ki both coordination number and stabiHty with heavier haHdes. No stable F complexes are known. [FeF (H20)] is the predominant kon fluoride species ki aqueous solution. The [FeF ] ion can be prepared ki fused salts. Whereas six-coordinate [FeCy is known, four-coordinate complexes are favored for chloride. Salts of tetrahedral [FeCfy] can be isolated if large cations such as tetraphenfyarsonium or tetra alkylammonium are used. [FeBrJ is known but is thermally unstable and disproportionates to kon(II) and bromine. Complex anions of kon(II) hahdes are less common. [FeCfy] has been obtained from FeCfy by reaction with alkaH metal chlorides ki the melt or with tetraethyl ammonium chloride ki deoxygenated ethanol. 

A number of chemiluminescent reactions may proceed through unstable dioxetane intermediates (12,43). For example, the classical chemiluminescent reactions of lophine [484-47-9] (18), lucigenin [2315-97-7] (20), and transannular peroxide decomposition. Classical chemiluminescence from lophine (18), where R = CgH, is derived from its reaction with oxygen in aqueous alkaline dimethyl sulfoxide or by reaction with hydrogen peroxide and a cooxidant such as sodium hypochlorite or potassium ferricyanide (44). The hydroperoxide (19) has been isolated and independentiy emits light in basic ethanol (45). 

If pure isomers are required, the ortho and meta compounds can be prepared by indirect methods. o-Nitrotoluene can be obtained by treating 2,4-dinitrotoluene with ammonium sulfide followed by diazotization and boiling with ethanol. / -Nitrotoluene can be prepared from -toluidine by acetylation, nitration deacetylation, diazotization, and boiling with ethanol. A fairly pure -nitrotoluene, which has been isolated from the isomeric mixture, can be purified further by repeated crystallization. 

There is no evidence for the existence of thallic hydroxide addition of hydroxide to an aqueous solution of a T1(III) salt gives TI2O2 instead. ThaHous hydroxide can be isolated as yellow needles by the hydrolysis of thaHous ethoxide [20398-06-5] which is conveniendy prepared as a heavy oH by the oxygen oxidation of thallium metal in ethanol vapor. ThaHous hydroxide darkens at room temperature and decomposes to TI2O and H2O on warming. 

TYZOR ET is reduced by sodium and ethanol to a dark-blue compound (182). Use of potassium as the reducing agent in the alcohol permits the isolation and identification of Ti(OC2H2)3 [22922-82-3] and Ti(OC4Hg)3 [5058-41-3] (183,184). The products precipitate as soUd alcoholates,... 

DAG is treated with ethanol and hydrochloric acid in the presence of inert solvent, eg, chlorinated solvents, hydrocarbons, ketones, etc. The L-ascorbic acid precipitates from the mixture as it forms, minimising its decomposition (69). Cmde L-ascorbic acid is isolated through filtration and purified by recrystallization from water. The pure L-ascorbic acid is isolated, washed with ethanol, and dried. The mother Hquor from the recrystallization step is treated in the usual manner to recover the L-ascorbic acid and ethanol contained in it. The cmde L-ascorbic acid mother Hquor contains solvents and acetone Hberated in the DAG hydrolysis. The solvents are recovered by fractional distillation and recycled. Many solvent systems have been reported for the acid-catalyzed conversion of DAG to L-ascorbic acid (46). Rearrangement solvent systems are used which contain only the necessary amount of water required to give >80% yields of high purity cmde L-ascorbic acid (70). 

Enzymes. Invertase (P-fmctofuranosidase) is commercially produced from S. cerevisiae or S. uvarum. The enzyme, a glycoproteia, is not excreted but transported to the cell wall. It is, therefore, isolated by subjecting the cells to autolysis followed by filtration and precipitation with either ethanol or isopropanol. The commercial product is available dry or ia the form of a solutioa containing 50% glycerol as a stabilizer. The maia uses are ia sucrose hydrolysis ia high-test molasses and ia the productioa of cream-ceatered candies. 

---