Ethanol under pressure

Conditions Heat with an excess of a concentrated solution of ammonia in ethanol under pressure in a sealed tube... 

The y-modification is produced by heating crude quinacridone in ethanol (under pressure) or in dimethylformamide or dimethylsulfoxide at 150°C. 

When the complex Co2(CO)g(HC2H) is heated in ethanol under pressure of carbon monoxide, the organic products ethyl acrylate, ethyl propionate, and diethyl succinate are formed 23). A mechanism (Scheme 3) has been proposed for this reaction, and it is interesting to note that... 

Obtained by heating its dimethyl or diethyl ether with potassium hydroxide in dilute ethanol under pressure at 175° (55-59%) [1737],... 

If a halogenoalkane is heated with an excess of ammonia dissolved in ethanol under pressure, an amine is formed. 

Manufactured by the liquid-phase oxidation of ethanal at 60 C by oxygen or air under pressure in the presence of manganese(ii) ethanoate, the latter preventing the formation of perelhanoic acid. Another important route is the liquid-phase oxidation of butane by air at 50 atm. and 150-250 C in the presence of a metal ethanoate. Some ethanoic acid is produced by the catalytic oxidation of ethanol. Fermentation processes are used only for the production of vinegar. 

Ethanol can also be obtained by the reaction of methanol with synthesis gas at 185°C and under pressure (6.9—20.7 MPa or 68—204 atm) in the presence of a cobalt octacarbonyl catalyst (177). However, although ethanol was the primary product, methyl formate, methyl, propyl and butyl acetates, propyl and butyl alcohols, and methane were all present in the product. 

In a German patent issued in 1929, Bergs described a synthesis of some 5-substituted hydantoins by treatment of aldehydes or ketones (1) with potassium cyanide, ammonium carbonate, and carbon dioxide under several atmospheres of pressure at 80°C. In 1934, Bucherer et al. isolated a hydantoin derivative as a by-product in their preparation of cyanohydrin from cyclohexanone. They subsequently discovered that hydantoins could also be formed from the reaction of cyanohydrins (e.g. 3) and ammonium carbonate at room temperature or 60-70°C either in water or in benzene. The use of carbon dioxide under pressure was not necessary for the reaction to take place. Bucherer and Lieb later found that the reaction proceeded in 50% aqueous ethanol in excellent yields for ketones and good yields for aldehydes. ... 

Hydrogenolysis of esters to aldehydes or alcohols needs high temperatures and high pressures. Moreover, it leads to the formation of acids, alcohols, and hydrocarbons. In contrast, bimetallic M-Sn alloys (M = Rh, Ru, Ni) supported on sihca are very selective for the hydrogenolysis of ethyl acetate into ethanol [181]. For example while the selectivity to ethanol is 12% with Ru/Si02, it increases up to 90% for a Ru-Sn/Si02 catalyst with a Sn/Ru ratio of 2.5 [182]. In addition, the reaction proceeds at lower temperatures than with the classical catalysts (550 K instead of temperatures higher than 700 K). The first step is the coordination of the ester to the alloy (Scheme 46), and most probably onto the tin atoms. After insertion into the M - H bond, the acetal intermediate decomposes into acetaldehyde and an ethoxide intermediate, which are both transformed into ethanol under H2. 

Quite recently this reaction was revisited by Kappe [91] et al. who reinvestigated the Biginelli synthesis under the action of microwave irradiation under a variety of different conditions. At atmospheric pressure in ethanol solution there is no difference from conventional heating. Under pressure the yield is reduced and byproducts are formed. In an open system rate and yield enhancements are significant and this is rationalized by the rapid evaporation of the solvent which means that this is in fact a solvent-free reaction. This was confirmed by running the reaction without solvent under the action of microwaves and with thermal heating. (Scheme 8.65)... 

Reaction of acetic acid solutions of Ru3(CO)i2 with mixtures of CO and R2 under pressure produces substantial amounts of methyl acetate and smaller quantities of ethylene glycol diacetate/ as shown in Table I. Other products observed in these reactions are traces of glycerine triacetate and small amounts of ethyl acetate. (The ethanol is apparently derived largely from acetic acid by catalytic hydrogenation, since reactions in propionic acid solvent yield similar quantities of propyl propionate and only traces of ethyl propionate.)... 

Substitution of halogens on heteroaromatic rings is a common way to introduce new functionalities. The product from reaction 6 (Scheme 6) was required on a 100-g scale as an intermediate. In the literature, this exchange was done on a 5-g scale using ammonia in ethanol in a sealed tube under pressure for 6 h at 125-130°C with a yield of 76% (Bendich et al. 1954). Because of the lack of a suitable autoclave for high-pressure reactions, we choose the microwave reactor for scale-up trials. Using our Synthos 3000 equipment, we found suitable conditions with only minimal optimization at 170°C for 180 min and obtained the desired product on a 60-g scale in 83% yield. 

In general, acyl azides are too unstable to survive at the temperatures required for addition to acetylenes, although benzoyl azide adds readily to ynamines in toluene. Ethoxycarbonyl azide also gives triazoles in good yield with ynamines. The azide adds to propargylic alcohols in boiling ethanol, and to acetylene at 100° under pressure. Addition to phenylacetylene and to electron-deficient acetylenes has been carried out at 130°. Oxazoles are also formed at this temperature by competing thermal decomposition of the azide, and addition of ethoxycarbonylnitrene to the acetylenes. The triazole obtained from phenylacetylene is 2-ethoxycarbonyl-4-phenyltriazole the two 1-ethoxycarbonyltriazoles can be isolated if the addition is carried out at 50° over several weeks. Since the IH- to -triazole isomerization takes place readily in these systems, a IH-structure cannot be assumed for a triazole formed by addition of these azides. 

Several studies have been concerned with the chemistry of the + ni oxidation state of these elements, and the characterization of the first tantalum(iii) compounds has been claimed. The diamagnetic dimer [TaCl3(MeCN)2]2 has been prepared and used to obtain [TaClafphen)], [TaCljfbipy)], and tris-(dibenzoylmethanato)tantalum(ni). NbFa has been characterized as the product of the reaction of Nb and NbF (1 1) at 750 °C under pressure. Electrolytic reduction of niobium(v) in ethanol,formamide, and dimethylformamide can afford preparative concentrations of niobium(iii) and the new compound niobium(iii) trilactate has been obtained from ethanol. 

Stipe powder of C. comatus (100 g) was extracted three times with 1 L 95% ethanol under reflux for 2 h to remove lipid, and the residue was extracted three times with 2 L distilled water for 2 h at 80 °C with intermediate centrifugation (2000 x g, 15 min). After concentrating the collected aqueous supernatants to 400 mL (reduced pressure at 40 °C), a precipitation was performed with 3 volumes of 95% ethanol. The precipitate was washed with ethanol and acetone, and then dried at 40 C, yielding crude polysaccharide material. Crude polysaccharide material was dissolved in 100 mL 0.2 M sodium phosphate buffer (pH 6.0), and after centrifugation the solution was applied to a DEAE-Sepharose CL-6B column. 

Enantioselectivity is drastically reduced by carrying out the reaction at high initial hydrogen pressure. For example, the reaction of (Z)-a-(benzamido)cinnamic acid in ethanol under initial H2 pressure of 4 atm gives the saturated product in 96-100% optical yield the same reaction at 50 atm produces only a 71 % yield. 

Some of the reactions we have mentioned are used for large-scale industrial production. For example, ethanol is made in quantity by the hydration of ethene, using an excess of steam under pressure at temperatures around 300° in the presence of phosphoric acid ... 

Fig. 40. Rates of formation of diethyl ether and ethylene from ethanol catalyzed by H,PW 204n as well as the amount of absorbed ethanol under the working conditions as a function of the partial pressure of ethanol at 403 K. (From Refs. 119, 243.)...

In addition, it has been reported that esters of 27 afford 1 when they are heated in hydrochloric acid, 5 49- 50 or in chloroform-ethanol-hydrochloric acid.125 Compound 32 has been converted into 1 in 50% yield by heating under pressure in water at 140° or by heating in aqueous acid.226,251... 

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