版塊導(dǎo)航: 正在加載中...

登錄注冊

應(yīng)《網(wǎng)絡(luò)安全法》要求，自2017年10月1日起，未進(jìn)行實(shí)名認(rèn)證將不得使用互聯(lián)網(wǎng)跟帖服務(wù)。為保障您的帳號能夠正常使用，請盡快對帳號進(jìn)行手機(jī)號驗(yàn)證，感謝您的理解與支持！

24小時(shí)熱門版塊排行榜

返回列表

本帖產(chǎn)生 1 個(gè) 翻譯EPI ，點(diǎn)擊這里進(jìn)行查看

筆墨輕點(diǎn)

新蟲 (初入文壇)

應(yīng)助: 0 (幼兒園)
金幣: 83.3
帖子: 23
在線: 6.9小時(shí)
蟲號: 3295912
注冊: 2014-06-27
專業(yè): 有機(jī)合成

[求助] 翻譯中文有機(jī)合成

To investigate the effects of solvent, the condensation reaction of benzaldehyde, dimedone, ethylacetoacetate, and ammonium acetate in various organic solvents at room temperature using 4.85 wt.% Ni0-nanoparticles as the catalyst was carried out. About 75% of the expectedproduct 4a was obtained when the solvent was ethanol. Obviously, thepolar solvents such as ethanol and acetonitrile [Table 2] were much better than non polar solvents. It was observed that in the presence ofsolvent the reaction takes more time to give high yields of product under similar ratio of the reactants. This may be due to the competitive adsorption of the solvent with the substrate molecule on the catalyst surface; hence reaction under solvent-free condition gives better yields in less time. The model reaction was carried out without any catalyst,but the product formation was in poor yield. Therefore, the catalyst plays an important role in the success of the reaction in terms of rate and yields of Hantzsch polyhydroquinoline derivatives. The reaction was also investigated with acid activated Mont. alone as catalyst and only a negligible amount of product formation was observed. Therefore, it is evident that supported Ni0 -nanoparticles are the active sites.

回復(fù)此樓

» 猜你喜歡

一志愿武理材料工程348求調(diào)劑已經(jīng)有6人回復(fù)
08工科 320總分求調(diào)劑已經(jīng)有11人回復(fù)
一志愿華中農(nóng)業(yè)071010，總分320求調(diào)劑已經(jīng)有6人回復(fù)
323求調(diào)劑已經(jīng)有5人回復(fù)
284求調(diào)劑已經(jīng)有5人回復(fù)
317求調(diào)劑已經(jīng)有16人回復(fù)
287求調(diào)劑已經(jīng)有9人回復(fù)
求調(diào)劑已經(jīng)有6人回復(fù)
308求調(diào)劑已經(jīng)有3人回復(fù)
環(huán)境學(xué)碩288求調(diào)劑已經(jīng)有6人回復(fù)

1樓 2014-09-25 10:30:35

已閱回復(fù)此樓關(guān)注TA 給TA發(fā)消息送TA紅花 TA的回帖

ssssllllnnnn

至尊木蟲 (知名作家)

Translator and Proofreader

翻譯EPI: 1690
應(yīng)助: 452 (碩士)
金幣: 31580.9
紅花: 100
帖子: 7681
在線: 19966.6小時(shí)
蟲號: 3328089
注冊: 2014-07-17
專業(yè): 腫瘤發(fā)生

【答案】應(yīng)助回帖

★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★
筆墨輕點(diǎn): 金幣+25, 翻譯EPI+1, ★★★★★最佳答案 2014-09-25 20:20:29

為研究溶劑的作用，在室溫條件下用各種有機(jī)溶劑和4.85%（重量百分比）的Nio納米顆粒作為催化劑對苯甲醛，雙甲酮，乙酰乙酸乙酯和醋酸銨進(jìn)行了縮合反應(yīng)。當(dāng)用乙醇為溶劑時(shí)，可以獲得約75％的預(yù)期產(chǎn)物。顯然，極性溶劑如乙醇和乙腈[表2]均明顯優(yōu)于非極性溶劑。據(jù)觀察，在反應(yīng)物比例相似的條件下，有溶劑存在時(shí)反應(yīng)需要更多時(shí)間以得到高產(chǎn)物產(chǎn)率。這可能是由于溶劑與催化劑表面上底物分子的競爭吸附作用; 因此，無溶劑條件下反應(yīng)，在更短的反應(yīng)時(shí)間內(nèi)能夠得到更好的產(chǎn)率。在沒有任何催化劑存在的模型反應(yīng)，形成產(chǎn)物的產(chǎn)率低。因此，催化劑在合成Hantzsch多聚羥基喹啉衍生物的反應(yīng)中，不管在反應(yīng)速率還是產(chǎn)率方面的成功都發(fā)揮重要作用。同時(shí)還以酸活化蒙脫石為催化劑單獨(dú)使用，研究了反應(yīng)情況，結(jié)果產(chǎn)物產(chǎn)量可以忽略不計(jì)。顯而易見，支持的Nio納米顆粒是活性位點(diǎn)。

贊一下

回復(fù)此樓

2樓2014-09-25 13:13:22

已閱回復(fù)此樓關(guān)注TA 給TA發(fā)消息送TA紅花 TA的回帖

相關(guān)版塊跳轉(zhuǎn) 我要訂閱樓主筆墨輕點(diǎn) 的主題更新