Ethanol at high temperature

Alcell [Alcohol cellulose] A process for delignifying wood pulp by dissolving it in aqueous ethanol at high temperature and pressure. Developed by Repap Technologies, United States. 

Rosa, M.F., Sa Correia, I., and Novais, J.M., Production of ethanol at high temperatures in the fermentation of Jerusalem artichoke juice and a simple medium by Kluyveromyces marxianus, Biotechnol. Lett., 9, 441 144, 1987. 

Ouabaine is another example of a compound that exhibits many different hydration levels, the most hydrated form being stable at the lowest temperature. Thus the nonahydrate phase of ouabaine is obtained from water at 0-15°C, the octahydrate phase at 15-28°C, and the dihydrate phase at 28-90°C. In addition, ouabaine phases corresponding to 4.5 H2O, 4 H2O, and 3 H O may be obtained from mixtures of water with other solvents. The anhydrous phase of ouabaine anhydrate is crystallized from ethanol at high temperatures [63]. 

Ethanologenesis Bacteria with the ability to ferment and produce ethanol at high temperatures are ideal candidates for developing economically... 

The formation of acetaldehyde and acetic acid is due to the fact that rupture of the C-C bond in the original ethanol molecule would be required for CO2 formation. In the chemical oxidation of ethanol at high temperatures (combustion), this bond is readily ruptured in the hot flame, and the only reaction product (in addition to water) is CO2. In electrochemical oxidation occurring at temperatures below 2(X)°C, this bond is very difficult to rupture, and reactions involving the sole rupture of C-H bonds occur much more readily, thus leading to the side products noted. 

Bromoacetic acid can be prepared by the bromination of acetic acid in the presence of acetic anhydride and a trace of pyridine (55), by the HeU-VoUiard-Zelinsky bromination cataly2ed by phosphoms, and by direct bromination of acetic acid at high temperatures or with hydrogen chloride as catalyst. Other methods of preparation include treatment of chloroacetic acid with hydrobromic acid at elevated temperatures (56), oxidation of ethylene bromide with Aiming nitric acid, hydrolysis of dibromovinyl ether, and air oxidation of bromoacetylene in ethanol. 

Organic fluids also are mixed with water to serve as secondary coolants. The most commonly used fluid is ethylene glycol. Others include propjiene glycol, methanol (qv), ethanol, glycerol (qv), and 2-propanol (see Propyl alcohols, isopropyl alcohol). These solutions must also be inhibited against corrosion. Some of these, particularly methanol, may form flammable vapor concentrations at high temperatures. 

In other work Rozen added molecular fluorine to a steroidal ene-one dissolved in ethanol at low temperatures to produce a vicinal difluonde in a cleaner, better yield reaction than previously obtainable [55] Although the reaction was not general, the stereoselectivity was very high, and contrary to addition of other halogens, addition was r>ii, characteristic of an electrophilic addition pathway... 

The product is hydrogenated in 4,000 cc of ethanol at room temperature and under normal atmospheric pressure with a catalyst prepared In the usual manner from 400 g of Raney nickel alloy. The calculated amount of hydrogen is taken up in approximately 75 hours. After filtration and evaporation to a small volume, the residue Is distributed between 1,000 cc of chloroform and water each. The chloroform solution is then dried over sodium sulfate and evaporated to a small volume. Precipitation of the hydrogenation product with petroleum ether yields an amorphous white powder which Is filtered by suction, washed with petroleum ether and dried at 50°C In a high vacuum. 1. athyl-2-podophyllinic acid hydrazide is obtained in a practically quantitative yield. 

On the other hand, refluxing 9 in formic acid for 5 h afforded the N-formyl derivative 11 in high yield. Acetylation of 9 by refluxing in acetic acid, afforded acetic acid N -(2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-acetyl)-hydrazide 12 in good yield. Compound 13 was also obtained by refluxing 9 with 3-(2-bromoacetyl)-4-hydroxy-2H-chromen-2-one in ethanol. Reaction of compound 9 with phenyl isothiocyanate in ethanol at room temperature gave 4-phenyl-1 - (7-hydroxy-2-oxo-2 H-chromen-4-acetyl- )thiosemicarbazide 14. 

Arico AS, Creti P, Antonucci PL, Antonucci V. 1998. Comparison of ethanol and methanol oxidation in a liquid-feed solid polymer electrolyte fuel cell at high temperature. Electrochem Sol Lett 1 66-68. 

Further reaction of 7-azanorbomadiene 171 at room temperature with NZ pyrrole 166 under high pressure, followed by removal of the Z-protecting groups by hydrogenolysis yielded the deprotected diazasesquinorbomane 173. The last step required prolonged treatment with Pd/C (10%) in ethanol at room temperature and moderate pressure (30 psi) for 3 days, conditions that... 

SRE (Fig. 7) and POE (Fig. 10) reactions, a maximum yield of H2 could be attained in the OSRE reaction above 600 °C because CH4, if formed as an intermediate by ethanol decomposition could be completely converted into syngas above this temperature.7,8,10,109 The participation of reverse WGS reaction at high temperature leads to an increase in CO composition above 400 °C with a concomitant decrease in the composition of C02. Thus, at higher operating temperatures of above 600 °C, the system would produce mainly syngas rather than a mixture of H2 and C02. A comparison of equilibrium compositions of POE and OSRE reactions indicates that the presence of steam in this system increases the maximum yield of H2 from about 50% in the POE reaction (Fig. 10) to about 65% in the OSRE, and this is very close to that observed in the SRE reaction (around 70%) due to the participation of steam... 

The most exciting application of bond order indices concerns the description of chemical reactions involving the simultaneous change of several bonds. An example is the unimolecular decomposition of ethanol, which can happen at high temperature or IR multiphoton excitation of the molecule. Out of the possible dissociation channels, the lowest barrier characterizes the concerted water loss of the molecule, yielding ethene and H20 [30]. 

Dealkylation of quaternary ammonium salts using ethanol-amine is more convenient than the use of aqueous ammonia in sealed tubes at high temperatures. Ethanolamine may be replaced by other ethanolamines. The reaction leads to preferential removal of methyl groups. 

When HI Is In excess and the reaction Is carried out at high temperature, ethanol reacts with another molecule of HI and Is converted to ethyl iodide. 

In an acidic medium, a PEMFC fed with ethanol allows power densities up to 60 mW cm to be reached at high temperatures (80-120 °C), but this needs platinum-based catalysts, which may prevent wider applications for portable electronic devices. On the other hand, in an alkaline medium, the activity of non-noble catalysts for ethanol or ethylene glycol oxidation and oxygen reduction is sufficient to reach power densities of the order of 20 mW cm at room temperature. This opens up the hope of developing SAMFCs that are particularly efficient for large-scale portable applications. 

Extensive experimental and theoretical studies on hydrogen production from SRE have been reported. In the thermodynamic studies carried out by Vasudeva et al. [190], it was reported that in all ranges of conditions considered, there is nearly complete conversion of ethanol and only traces of acetaldehyde and ethylene are present in the reaction equilibrium mixture. Methane formation is inhibited at high water-to-ethanol ratios or at high temperatures [191]. 

The presence of oxygen enhances the catalyst stability. Breen et al. [187] investigated SRE over a range of oxide-supported metal catalysts. They concluded that the support plays an important role in the reaction. In fact, they observed that alumina-supported catalysts are very active at low temperatures for dehydration of ethanol to ethylene, which at higher temperatures (550 °C) is converted into H2, CO and CO2 as major products and CH4 as a minor product. The activities of the metal decrease in the order of Rh > Pd > Ni PS Pt. Ceria/zirconia-supported catalysts are more active and exhibit 100% conversion of ethanol at high space velocity and high temperature (650 °C). 

White orthorhombic crystals, produced in the form of pellets, lumps, sticks, beads, chips, flakes or solutions hygroscopic very corrosive rapidly absorbs CO2 and water from the air density 2.13 g/cm melts at 323°C vaporizes at 1388°C vapor pressure 1 torr at 739°C and 5 torr at 843°C very soluble in water (110 g/lOOmL at room temperature), generating heat on dissolution aqueous solutions highly alkaline, pH of 0.5% solution about 13 and 0.05% solution about 12 soluble in methanol, ethanol and glycerol (23.8 g/100 mL methanol and 13.9 g/100 mL ethanol at ambient temperatures.)... 

A substantial difficulty in ethanol SR is a too rapid catalyst deactivation due to coking. This can occur by several reactions, such as methane decomposition (19) or the Boudouard reaction (20), but primarily the polymerization of ethylene is thought to cause the problems (21). Unlike the situation for methane SR, it appears that for ethanol SR the deactivation by coke formation is lower at high temperatures. 

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