Ethanol synthesi

Ethyl Ether. Most ethyl ether is obtained as a by-product of ethanol synthesis via the direct hydration of ethylene. The procedure used for production of diethyl ether [60-29-7] from ethanol and sulfuric acid is essentially the same as that first described in 1809 (340). The chemical reactions involved in the production of ethyl ether by the indirect ethanol-from-ethylene process are like those for the production of ether from ethanol using sulfuric acid. 

Methanol can then be used as a starting material for the synthesis of alkenes, aromatic compounds, acetic acid, formaldehyde, and ethyl alcohol (ethanol). Synthesis gas can also be nsed to produce methane, or synthetic natrrral gas (SNG) (Demirbas, 2007) ... 

Bimetallic supported Co-Rh catalysts are very active towards the ethanol synthesis from CO and very effective in ethylene hydroformylation to C3 oxygenates (n-propanal and n-propanol). 

The situation with regard to ethanol is much clearer there is long industrial experience in the manufacture of ethanol from wood, by fermentation of the sugars in the waste effluents of pulp mills, or of the sugars made by wood hydrolysis ( ). In the years following World War II, wood hydrolysis plants have been unable to compete economically with petroleum-based ethanol synthesis, mainly by hydration of ethylene, and they have been shut down in most countries. However, in the Soviet Union, we understand, there are still about 30 wood hydrolysis plants in operation (10). Many of these are used for fodder yeast production (11) but the wood sugars are also available for ethanol production. 

Analogous results have been obtained with our Rh-CeO /SiO catalysts (60), suggesting that acetaldehyde is a possible intermediate in ethanol synthesis on rhodium catalysts. 

When plants experience anoxic conditions there is a shift in carbohydrate metabolism from an oxidative to a fermentative pathway (Fig. 1). In the absence of oxygen, ATP is generated not by the Krebs cycle but by alcoholic fermentation, i.e. glycolysis and ethanol synthesis. 

We have been studying the anaerobic response in cotton, a crop which experiences a reduction in growth rate during irrigation or waterlogging. Cotton shows a level of anaerobically inducible ADH activity comparable with that of maize, a plant which is relatively resistant to anoxia (A. Millar, unpublished data T.L. Setter, unpublished data). However, in cotton the level of the enzyme catalysing the preceding step in the fermentation pathway, PDC, is relatively low and this may lead to low rates of ethanol synthesis and hence low tolerance to anoxia. 

Selcciive ethanol synthesis over supported rhodium catalysts 1147 a... 

After biochemical conversion of glucose to pyruvic acid intermediate, the next step in ethanol synthesis is nonoxidative decarboxylation and acetaldehyde formation catalyzed by a native decarboxylase, and then acetaldehyde reduction to ethanol catalyzed by a native dehydrogenase. 

Synthetic ethanol is now produced by hydration of ethylene. Ethanol is one of important chemicals. Though ethanol synthesis from H2/CO was extensively studied so far, there are a few reports about ethanol synthesis from H2/CO2. Recently, some efficient catalysts for ethanol formation from H2/CO2 were developed by Arakawa and his co-workers. 

Ethanol synthesis bv promoted Rh/ Si02 catalyst It is known that ethanol can be synthesized efficiently from H2/CO by promoted Rh/Si02 catalyst.[42.43] Based on this result, promoted Rh/Si02 catalysts were tested for C02 hydrogenation to ethanol. [44,45] As a result, it has proved that Sr, Li and Fe additives are effective for ethanol formation. [46,47] Typical results are shown in Table 4. [48] It is speculated reaction proceeds via equation(l) and (2). Acetyl species, formed by CO insertion to methyl species on Rh surface, is supposed to be a possible reaction intermediate. 

The effect of rhodium precursor on ethanol synthesis by catalytic hydrogenation of carbon dioxide over silica supported rhodium catalysts... 

In our previous studies, CO2 was converted to methane[2] or methanol[3] at extraordinarily rapid conversion rates. However, rapid ethanol synthesis from CO2 has been much more difficult owing to both equilibrium limitation and retardation caused by H2O, which inevitably forms in the CO2 hydrogenation. In this study, to synthesize ethanol from CO2 with higher yield, a catalyst (Cu-Zn-Al-K mixed oxides) having a function of partial reduction of CO2 was combined with a Fe based F-T type catalyst which we had already developed[l]. Then Pd and Ga, which have promotion effect for Cu-Zn based methanol synthesis catalyst[3], were added to modify the catalyst, and the performance was examined. 

The Fe-Cu-Al-K ethanol synthesis catalyst(Cat. 1) and Cu-Zn-Al-K catalyst(Cat. 2) were prepared by applying the uniform-gelatin method[4]. A... 

Performances of each catalyst is shown in Figure 1. The ethanol synthesis catalyst (Fe-based catalyst. Cat. 1) have both functions of F-T synthesis and alcohol synthesis. The main products were hydrocarbons, ethanol and methanol. With the increase of CO in reaction gas, the yield of ethanol increased[l]. The Cu-based catalyst (Cat. 2) converted CO2 to CO with selectivity more than 70% at a temperature range from 270 to 370°C, and other products were methanol and a slight amount of methane. Ethanol and C2 hydrocarbons were not produced. In order to harmonize the three functions, C-C bond growth, partial reduction of CO2 to CO, and OH insertion to products, the mixed ratio of Fe-based catalyst to Cu-based catalyst was coordinated at the range from Cu/Fe =... 

A study for the durability of catalysts in ethanol synthesis by hydrogenation of carbon dioxide ... 

The durability of catalysts in ethanol synthesis by the hydrogenation of COj was investigated by means of XRD, TEM, and EDS. The K/Cu-Zn-Fe oxides catalyst was deactivated by the segregation of catalyst components to FeCOj, ZnO, and Cu during the reaction. The segregation was prevented by the addition of Cr component to the catalyst. Consequently, the K/Cu-Zn-Fe-Cr oxides catalyst indicates long catalytic life. 

Ethanol synthesis from carbon dioxide and hydrogen... 

K/Cu-Zn-Fe oxides catalyst was found effective for ethanol synthesis by the catalytic hydrogenation of COj. The catalyst gave an ethanol selectivity of 20C-% with a CO conversion of 44% at 7.0MPa, 300°C, GHSV 5,000, and Hj/CO in the feed 3(mol). The ethanol STY of 290 g/L-cat-h was achieved at the GHSV of 20,000. The addition of Cr reduced the deactivation of the catalyst remarkably. The K/Cu-Zn-Fe-Cr oxides catalyst was revealed useful for practical purposes. 

Catalyst search was carried out in order to find the effective ones for ethanol synthesis from CO2/H2 and the results were summarized in Table 1. 

K/Cu-Zn-Fe oxides catalyst has good activity and selectivity in ethanol synthesis from COj/Hj as described above. However, its activity was found to decline quickly during the reaction. In order to prevent the deactivation of the catalyst, the additions of 5 th component to the catalyst were studied extensively and Cr was found to have a remarkable effect. The effects of Cr addition are shown in Figure 4. In the reaction over K/Cu-Zn-Fe-Cr oxides catalyst COj conversion as well as ethanol selectivity attained steady values after 40 hours. At the steady state,... 

K/Cu-Zn-Fe-Cr oxides catalyst obtained in this study is revealed available for the ethanol synthesis by the hydrogenation of COj in practice. 

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