
活性(xing)炭的環己(ji)烷氧(yang)化
今天,我想介紹(shao)一(yi)下環(huan)(huan)己(ji)烷(wan)(wan)無溶劑(ji)氧化(hua)(hua)活性炭(tan)(tan)。活性炭(tan)(tan)的(de)原料(liao)是磷酸鹽浸(jin)泡在(zai)380中(zhong)℃在(zai)惰性氣體下碳化(hua)(hua),然(ran)后(hou)用過(guo)氧化(hua)(hua)氫激活。活性炭(tan)(tan)通過(guo)SEM,EDX,FTIR,TGA和BET表(biao)面(mian)積和孔徑分析儀表(biao)征。在(zai)自(zi)制雙壁三頸批量中(zhong),活性炭(tan)(tan)作為環(huan)(huan)己(ji)烷(wan)(wan)無環(huan)(huan)氧化(hua)(hua)成環(huan)(huan)己(ji)醇和環(huan)(huan)己(ji)酮(這種混(hun)合(he)物稱為KA油)催化(hua)(hua)劑(ji)的(de)潛能反(fan)應堆。優化(hua)(hua)了不(bu)同反(fan)應參(can)數/添加劑(ji)的(de)影(ying)響。
19世紀初,活性炭首次(ci)被報道為有(you)效催(cui)化(hua)(hua)劑。19世(shi)紀初,活(huo)性(xing)(xing)(xing)炭通常由不同農業原料的(de)熱(re)活(huo)化(hua)(hua)法制備,作為過氧(yang)(yang)化(hua)(hua)氫降(jiang)解(jie)的(de)催(cui)化(hua)(hua)劑。活(huo)性(xing)(xing)(xing)炭對過氧(yang)(yang)化(hua)(hua)氫分解(jie)有(you)很好的(de)催(cui)化(hua)(hua)活(huo)性(xing)(xing)(xing),但持續(xu)時間短。催(cui)化(hua)(hua)活(huo)性(xing)(xing)(xing)消失的(de)*有(you)可(ke)能原因是(shi)活(huo)性(xing)(xing)(xing)炭表面氧(yang)(yang)化(hua)(hua)基團的(de)失活(huo)。近幾十(shi)年來,研(yan)究人員(yuan)成功地(di)解(jie)決了活(huo)性(xing)(xing)(xing)炭耐久性(xing)(xing)(xing)的(de)主要問題。活(huo)性(xing)(xing)(xing)炭通過物理(li)、物理(li)、化(hua)(hua)學和化(hua)(hua)學活(huo)化(hua)(hua)進行調整(zheng),在光氣和硫化(hua)(hua)氫的(de)生產中顯示出良好的(de)催(cui)化(hua)(hua)活(huo)性(xing)(xing)(xing),氫化(hua)(hua)、聚合(he)和鹵化(hua)(hua)去(qu)除SO 2 和NO x 氧(yang)(yang)化(hua)(hua)苯二醇。由于其孔隙度、活(huo)性(xing)(xing)(xing)位(wei)點和高表面積(ji),活(huo)性(xing)(xing)(xing)炭的(de)這(zhe)種性(xing)(xing)(xing)能。因此,通過控制這(zhe)些(xie)參數,活(huo)性(xing)(xing)(xing)炭可(ke)以調整(zheng)為有(you)效的(de)催(cui)化(hua)(hua)劑,用于選擇有(you)機轉化(hua)(hua)。
活性炭實驗條件(jian)和(he)工藝條件(jian)
在目(mu)前的(de)(de)工作中,在溫(wen)和(he)(he)的(de)(de)反應條件下,活(huo)性(xing)炭被用(yong)作無(wu)金屬催(cui)化(hua)劑(ji)和(he)(he)無(wu)環(huan)(huan)(huan)氧(yang)環(huan)(huan)(huan)己烷(wan)KA油。優化(hua)了(le)(le)反應參數,并在生產率方(fang)面發現了(le)(le)催(cui)化(hua)效率。活(huo)性(xing)炭成為環(huan)(huan)(huan)己烷(wan)無(wu)溶劑(ji)氧(yang)化(hua)的(de)(de)有用(yong)催(cui)化(hua)劑(ji),方(fang)便、活(huo)性(xing)、低成本、可回收、不滲透、環(huan)(huan)(huan)保。

活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)的表(biao)面(mian)形態是通過(guo)掃描電子顯(xian)微鏡進行研(yan)究的。活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)的元素組成通過(guo)能(neng)量(liang)色散X射線(xian)光譜(pu)記錄。通過(guo)X射線(xian)衍射儀(yi)進行X射線(xian)分(fen)析。活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)表(biao)面(mian)的官能(neng)團通過(guo)傅里葉紅外光譜(pu)儀(yi)檢查。通過(guo)TGA0/10000熱分(fen)析儀(yi)℃溫度范圍內(nei) 以10℃/ min的速率在(zai)N 2流(liu)下熱量(liang)重量(liang)損失百分(fen)比 。活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)面(mian)積分(fen)析儀(yi)測量(liang)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)的表(biao)面(mian)積。
將環己(ji)烷(wan)(12.5mL)和活性炭(0.4g)裝(zhuang)載到自設(she)雙壁三口式間歇式反應器中(zhong)。在分子氧(40mL / min)存在下(xia),在75℃攪拌混合物14小(xiao)時 。堿(jian)性在同一組反應參數中(zhong)NaOH:0.2 mmole的存在下(xia)也進行反應。環自烷(wan)通過氣相色譜分析轉化為KA油,使(shi)用交聯甲基硅氧烷(wan)毛細管柱(30μm,內徑0.32mm, 米 m膜厚(hou)),火焰(yan)離子化檢測(ce)器(FID)相連。
通(tong)(tong)過SEM分析活性(xing)炭(tan)的表面(mian)形(xing)態。SEM圖(tu)(tu)為多(duo)孔(kong)結(jie)構、微(wei)孔(kong)/中孔(kong)與活性(xing)炭(tan)內表面(mian)連接的交聯通(tong)(tong)道的混合 1 。高放大(da)倍(bei)率顯(xian)示(shi)2-10腔的存在(zai)μ 米(mi) ,內部微(wei)孔(kong)和中孔(kong)可以很容易(yi)地(di)訪問。EDX分析(圖(tu)(tu) 2 )磷和二(er)氧化硅顯(xian)示(shi)痕跡, 這些是花生殼的主(zhu)要內容。
討論活性炭(tan)實驗(yan)結果
含(han)(han)氧(yang)(yang)(yang)官(guan)能(neng)(neng)(neng)團(tuan)(tuan)負責(ze)將環(huan)(huan)(huan)(huan)己烷(wan)(wan)氧(yang)(yang)(yang)化(hua)(hua)成(cheng)環(huan)(huan)(huan)(huan)己醇和(he)環(huan)(huan)(huan)(huan)己酮(tong)。據(ju)廣泛報道(dao),活性(xing)炭表面和(he)分子氧(yang)(yang)(yang)通(tong)過(guo)(guo)含(han)(han)氧(yang)(yang)(yang)官(guan)能(neng)(neng)(neng)團(tuan)(tuan),如(ru)堿、酮(tong)和(he)醌。此外,通(tong)過(guo)(guo)含(han)(han)氧(yang)(yang)(yang)表面官(guan)能(neng)(neng)(neng)團(tuan)(tuan)活性(xing)炭氧(yang)(yang)(yang)化(hua)(hua)反(fan)應(ying),這些(xie)官(guan)能(neng)(neng)(neng)團(tuan)(tuan)通(tong)過(guo)(guo)分子氧(yang)(yang)(yang)再(zai)生(sheng)。酚(fen)基是環(huan)(huan)(huan)(huan)己烷(wan)(wan)氧(yang)(yang)(yang)化(hua)(hua)*穩(wen)定、*主要的(de)(de)來源,除其它含(han)(han)氧(yang)(yang)(yang)基團(tuan)(tuan)外。對苯(ben)二酚(fen)系統的(de)(de)芬(fen)頓樣(yang)機制(zhi)是環(huan)(huan)(huan)(huan)己烷(wan)(wan)氧(yang)(yang)(yang)化(hua)(hua)傳(chuan)播*有可(ke)能(neng)(neng)(neng)的(de)(de)方(fang)式(shi)。喹諾酮(tong)通(tong)過(guo)(guo)連續氧(yang)(yang)(yang)氣在反(fan)應(ying)混合物(wu)中再(zai)生(sheng)。化(hua)(hua)學(xue)/熱處理可(ke)用(yong)于表面官(guan)能(neng)(neng)(neng)團(tuan)(tuan)(品種/密度)。例如(ru),在*近(jin)的(de)(de)研究中TGA活性(xing)炭表面產生(sheng)的(de)(de)氧(yang)(yang)(yang)官(guan)能(neng)(neng)(neng)團(tuan)(tuan)通(tong)過(guo)(guo)熱處理進行調整。高(gao)溫580活性(xing)炭℃下處理;。因此,**現有的(de)(de)含(han)(han)氧(yang)(yang)(yang)官(guan)能(neng)(neng)(neng)團(tuan)(tuan)將是醌。確認高(gao)溫(700°C)下醌官(guan)能(neng)(neng)(neng)團(tuan)(tuan)的(de)(de)穩(wen)定性(xing)。同樣(yang),喹諾酮(tong)官(guan)能(neng)(neng)(neng)團(tuan)(tuan)的(de)(de)穩(wen)定性(xing)高(gao)達800°C。因此,綜(zong)上(shang)所述,環(huan)(huan)(huan)(huan)己烷(wan)(wan)氧(yang)(yang)(yang)化(hua)(hua)成(cheng)環(huan)(huan)(huan)(huan)己醇和(he)環(huan)(huan)(huan)(huan)己酮(tong)遵循方(fang)案所示的(de)(de)機制(zhi) 。
活(huo)(huo)性炭通過(guo)化學方法合(he)成,環(huan)己烷中無溶劑(ji)氧(yang)化低分子(zi)氧(yang)。活(huo)(huo)性炭通過(guo)熱(re)處理進行調節,以發展表(biao)面上的酚官(guan)能(neng)(neng)團(tuan)。*佳(jia)反(fan)應(ying)參數(shu)如(ru)下:反(fan)應(ying)物115.56mmol、活(huo)(huo)性炭0.4g、 溫度75℃、時間14小時。將催(cui)化劑(ji)的催(cui)化活(huo)(huo)性與當前研究重要性生(sheng)產(chan)率報告(gao)的文獻進行比較。催(cui)化劑(ji)重復使(shi)用(yong)幾(ji)次,說明(ming)催(cui)化劑(ji)的耐久性。結果(guo)表(biao)明(ming),醌(kun)基官(guan)能(neng)(neng)團(tuan)是(shi)分子(zi)氧(yang)化環(huan)己烷再生(sheng)的*佳(jia)反(fan)應(ying)核心。發現活(huo)(huo)性炭是(shi)真正具有延長壽(shou)命(ming)的異相催(cui)化劑(ji)。
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