甲醇合成的外文翻译---酒精溶剂的催化效应(编辑修改稿)

甲醇合成的外文翻译---酒精溶剂的催化效应(编辑修改稿)内容摘要：

a result, ROH attacked the carbon atom of HCOOCu, the intermediate of step (2), more slowly. But the spatial obstacle of 1butanol is the smallest among all butanols, and this is favorable to the nucleophilic attack in the esterification reaction. On the other hand, isobutanol has high electronic density in its oxygen atom and this should accelerate the reaction. But its large molecular volume became a severe spatial obstacle in the nucleophilic attack. So its esterification rate was low. As a balanced effect between electronic factor and spatial factor, 2butanol exhibited highest activity among 4 butanols, in the ratedetermining step (2). As the opposite example, tertbutyl alcohol gave the yield of methanol as low as % here. It should be pointed out that the accumulated ester (HCOOR) can be easily transferred to methanol and ROH under higher H2 partial pressure. Two experiments were conducted to demonstrate this. One was the hydrogenation of ethyl formate in a batch reactor and the other was the hydrogenation of 2butyl formate in a flowtype semibatch autoclave reactor. For the first one, the reaction conditions were similar to those used in the synthesis reaction of methanol described above. A mixture gas of H2 and N2 with a total initial pressure of 30 bar (20 bar H2 and 10 bar N2) was used as feed gas. Ethyl formate ( mL) and mL of cyclohexane were mixed and poured into the reactor instead of 20 mL of alcohol. After 2 h reaction, the total 外文资料原文 6 conversion of ethyl formate was % and the yield of methanol was %. Methyl formate and CO were byproducts. Methyl formate might e from the transesterification of ethyl formate and the methanol produced. CO might e from the deposition of ethyl formate. For the latter experiment, mL of 2butyl formate (5 times amount in volume of ethyl formate used in the first experiment) and mL of cyclohexane were poured in the reactor. A flow of pure H2 (20 mL/min, 30 bar) was used as flowing gas. After 8 h continuous reaction at 443 K, % of 2butyl formate was transferred to methanol and 2butanol. The total conversions were high while 2alcohols were utilized. But the yields to ester were also high, especially for 2pentanol. It is referred that step (3) above was slower if 2alcohols were used. In other cases, the rate of step (3) was much faster than that of step (2), resulting in the disappearance or very low yield of the corresponding esters. If the water was added to ethanol with the same molar amount as that of CO2 in the feed gas under standard conditions, and the same experiment was conducted, similar results were obtained. Water did not affect the reaction behavior at these reaction conditions. From the reaction mechanism above, water was only an intermediate, similar to the role of CO2 in steps (1)(3). In Table 2, the influence from various reactant gas position was investigated at 423 K where catalyst Cu/ZnO (B) was used. It is clear that the total reaction rate increased with the increasing of CO2 content in the syngas. The reaction of CO2 +H2 exhibited the highest reaction rate. It seems that methanol synthesis rate was faster from CO2+H2 than from CO+H2, supporting that step (1) in the reaction mechanism was reasonable. It is interesting that pure CO did not react, indicating carbonylation of alcohol to ester impossible. While using pure CO +H2 as reactant 外文资料原文 7 gas, ethyl formate formed but methanol was not obtained. The reaction rate was rather lower than that of CO2contained syngas. It is hard to determine the reaction route of pure CO +H2 now, as CO insertion to ethanol to form an ester was excluded. Maybe water contained in the ethanol (about 100150 ppm) reacted with CO to form CO2 and fulfilled steps (1) and (2). 4. Conclusions The use of alcohol, especially 2alcohols, as a catalytic solvent in the synthesis of methanol from CO/CO2/H2, not only realized a new lowtemperature methanol synthesis method, but also overcame drawbacks of the BNL method and other lowtemperature methanol synthesis methods. This effect from acpanying alcoholic solvent decreased greatly the temperature and pressure of the synthesis reaction on Cu/ZnO solid catalyst, via a new reaction path. This method is very promising to bee a new technology for lowtemperature methanol synthesis where purification of syngas is not necessary. Since the reaction employed conventional solid catalyst, very mild reaction conditions, and syngas containing CO2 and H2O, it might be a promising practical method for methanol synthesis at low temperature. In fact, when the amount (weight) of catalyst was increased, the conversion was increased linearly in our experiments. 5060% conversion was realized in a flowtype semibatch reactor, as lowtemperature methanol synthesis has no thermodynamic limitation.。