
活(huo)性炭的環(huan)己烷氧化
今天,我想介紹一下環(huan)(huan)己(ji)(ji)烷(wan)無(wu)溶劑氧化(hua)(hua)活(huo)性(xing)炭。活(huo)性(xing)炭的(de)(de)原料是磷酸(suan)鹽浸泡在(zai)380中℃在(zai)惰性(xing)氣體下碳化(hua)(hua),然后用過(guo)氧化(hua)(hua)氫激(ji)活(huo)。活(huo)性(xing)炭通過(guo)SEM,EDX,FTIR,TGA和(he)BET表面(mian)積和(he)孔徑分析(xi)儀表征。在(zai)自制雙壁三(san)頸批量中,活(huo)性(xing)炭作為環(huan)(huan)己(ji)(ji)烷(wan)無(wu)環(huan)(huan)氧化(hua)(hua)成環(huan)(huan)己(ji)(ji)醇和(he)環(huan)(huan)己(ji)(ji)酮(這(zhe)種混合物稱為KA油)催化(hua)(hua)劑的(de)(de)潛能反(fan)應(ying)(ying)堆。優化(hua)(hua)了不同反(fan)應(ying)(ying)參數/添加(jia)劑的(de)(de)影響。
19世紀初,活性炭首次被報(bao)道(dao)為有效催(cui)化(hua)(hua)劑。19世紀初(chu),活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭通(tong)常由不同農業(ye)原(yuan)(yuan)料(liao)的(de)熱(re)活(huo)(huo)(huo)化(hua)(hua)法制(zhi)備,作為過(guo)氧(yang)(yang)化(hua)(hua)氫(qing)降解的(de)催(cui)化(hua)(hua)劑。活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭對過(guo)氧(yang)(yang)化(hua)(hua)氫(qing)分(fen)解有很好的(de)催(cui)化(hua)(hua)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing),但持續時(shi)間短。催(cui)化(hua)(hua)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)消失的(de)*有可能原(yuan)(yuan)因(yin)是活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭表面氧(yang)(yang)化(hua)(hua)基團的(de)失活(huo)(huo)(huo)。近幾十年(nian)來,研究人員成功地解決(jue)了活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭耐久(jiu)性(xing)(xing)(xing)(xing)(xing)的(de)主要(yao)問題。活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭通(tong)過(guo)物理(li)、物理(li)、化(hua)(hua)學和(he)(he)化(hua)(hua)學活(huo)(huo)(huo)化(hua)(hua)進行調整(zheng)(zheng),在(zai)光氣和(he)(he)硫化(hua)(hua)氫(qing)的(de)生產(chan)中顯示(shi)出良好的(de)催(cui)化(hua)(hua)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing),氫(qing)化(hua)(hua)、聚合和(he)(he)鹵化(hua)(hua)去除SO 2 和(he)(he)NO x 氧(yang)(yang)化(hua)(hua)苯(ben)二醇。由于其(qi)孔隙(xi)度、活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)位點和(he)(he)高表面積,活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭的(de)這(zhe)(zhe)種性(xing)(xing)(xing)(xing)(xing)能。因(yin)此,通(tong)過(guo)控制(zhi)這(zhe)(zhe)些(xie)參數,活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)炭可以調整(zheng)(zheng)為有效的(de)催(cui)化(hua)(hua)劑,用于選(xuan)擇有機(ji)轉(zhuan)化(hua)(hua)。
活性炭實驗條件和工藝(yi)條件
在目(mu)前(qian)的工(gong)作中,在溫和的反(fan)應條件下,活(huo)性(xing)炭被用作無(wu)金屬(shu)催(cui)化劑(ji)和無(wu)環氧(yang)環己烷(wan)(wan)KA油(you)。優化了反(fan)應參數,并在生(sheng)產率(lv)方面發現(xian)了催(cui)化效率(lv)。活(huo)性(xing)炭成(cheng)為環己烷(wan)(wan)無(wu)溶劑(ji)氧(yang)化的有用催(cui)化劑(ji),方便、活(huo)性(xing)、低成(cheng)本、可回收、不滲透、環保。

活性炭(tan)(tan)的(de)表(biao)面(mian)形態是(shi)通(tong)(tong)過掃描電子顯微鏡進行(xing)研(yan)究的(de)。活性炭(tan)(tan)的(de)元(yuan)素組(zu)成通(tong)(tong)過能量色散X射線光譜(pu)記錄。通(tong)(tong)過X射線衍射儀進行(xing)X射線分(fen)(fen)析(xi)。活性炭(tan)(tan)表(biao)面(mian)的(de)官能團通(tong)(tong)過傅里(li)葉紅外(wai)光譜(pu)儀檢(jian)查。通(tong)(tong)過TGA0/10000熱分(fen)(fen)析(xi)儀℃溫度范(fan)圍內 以10℃/ min的(de)速率在(zai)N 2流下熱量重(zhong)量損失百(bai)分(fen)(fen)比(bi) 。活性炭(tan)(tan)面(mian)積分(fen)(fen)析(xi)儀測(ce)量活性炭(tan)(tan)的(de)表(biao)面(mian)積。
將(jiang)環己(ji)烷(wan)(12.5mL)和(he)活(huo)性炭(tan)(0.4g)裝載到自(zi)設雙壁三口式間歇式反應器中。在分(fen)子(zi)氧(yang)(40mL / min)存在下,在75℃攪拌混合(he)物14小時 。堿性在同一組(zu)反應參數中NaOH:0.2 mmole的存在下也進行(xing)反應。環自(zi)烷(wan)通過(guo)氣(qi)相色(se)譜分(fen)析轉化為KA油,使用交聯(lian)甲(jia)基硅氧(yang)烷(wan)毛細管(guan)柱(30μm,內徑(jing)0.32mm, 米(mi) m膜厚),火焰離子(zi)化檢測器(FID)相連。
通過(guo)SEM分(fen)析(xi)活(huo)性(xing)炭的表(biao)面(mian)形態(tai)。SEM圖為多(duo)孔(kong)結構(gou)、微(wei)孔(kong)/中孔(kong)與活(huo)性(xing)炭內表(biao)面(mian)連接的交(jiao)聯通道(dao)的混合 1 。高放大倍率顯示2-10腔的存在(zai)μ 米 ,內部微(wei)孔(kong)和(he)中孔(kong)可(ke)以很容(rong)(rong)易地訪問。EDX分(fen)析(xi)(圖 2 )磷和(he)二氧化硅顯示痕跡, 這些是花生殼的主要內容(rong)(rong)。
討論活性炭(tan)實(shi)驗結果
含氧(yang)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)負責將環(huan)(huan)己烷氧(yang)化(hua)成環(huan)(huan)己醇(chun)和(he)(he)環(huan)(huan)己酮。據廣泛報道,活(huo)性(xing)炭(tan)(tan)(tan)表(biao)面(mian)和(he)(he)分(fen)子(zi)氧(yang)通(tong)(tong)過含氧(yang)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan),如堿、酮和(he)(he)醌。此(ci)外,通(tong)(tong)過含氧(yang)表(biao)面(mian)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)活(huo)性(xing)炭(tan)(tan)(tan)氧(yang)化(hua)反應(ying)(ying),這些官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)通(tong)(tong)過分(fen)子(zi)氧(yang)再生。酚(fen)基(ji)是環(huan)(huan)己烷氧(yang)化(hua)*穩(wen)定、*主(zhu)要(yao)的來源,除其它含氧(yang)基(ji)團(tuan)(tuan)外。對(dui)苯二酚(fen)系(xi)統(tong)的芬頓樣機制是環(huan)(huan)己烷氧(yang)化(hua)傳播(bo)*有可能(neng)(neng)(neng)(neng)(neng)的方(fang)式。喹諾酮通(tong)(tong)過連續(xu)氧(yang)氣在反應(ying)(ying)混(hun)合物(wu)中再生。化(hua)學/熱(re)處理可用于表(biao)面(mian)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)(品種/密度)。例如,在*近的研究(jiu)中TGA活(huo)性(xing)炭(tan)(tan)(tan)表(biao)面(mian)產生的氧(yang)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)通(tong)(tong)過熱(re)處理進行調整。高溫(wen)580活(huo)性(xing)炭(tan)(tan)(tan)℃下(xia)處理;。因此(ci),**現有的含氧(yang)官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)將是醌。確認高溫(wen)(700°C)下(xia)醌官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)的穩(wen)定性(xing)。同樣,喹諾酮官(guan)能(neng)(neng)(neng)(neng)(neng)團(tuan)(tuan)的穩(wen)定性(xing)高達800°C。因此(ci),綜(zong)上所(suo)述,環(huan)(huan)己烷氧(yang)化(hua)成環(huan)(huan)己醇(chun)和(he)(he)環(huan)(huan)己酮遵循方(fang)案所(suo)示(shi)的機制 。
活(huo)(huo)性炭通(tong)過化(hua)(hua)學方法合成,環(huan)己(ji)烷(wan)中無溶劑氧(yang)化(hua)(hua)低(di)分子(zi)氧(yang)。活(huo)(huo)性炭通(tong)過熱(re)處理進(jin)(jin)行調節,以發(fa)展表面上的(de)酚(fen)官能(neng)團(tuan)。*佳反應(ying)參(can)數如下:反應(ying)物115.56mmol、活(huo)(huo)性炭0.4g、 溫度75℃、時間(jian)14小時。將催(cui)化(hua)(hua)劑的(de)催(cui)化(hua)(hua)活(huo)(huo)性與(yu)當前研究(jiu)重(zhong)要性生產率報告(gao)的(de)文獻進(jin)(jin)行比較(jiao)。催(cui)化(hua)(hua)劑重(zhong)復使用(yong)幾次(ci),說(shuo)明催(cui)化(hua)(hua)劑的(de)耐久性。結果表明,醌基(ji)官能(neng)團(tuan)是分子(zi)氧(yang)化(hua)(hua)環(huan)己(ji)烷(wan)再生的(de)*佳反應(ying)核心。發(fa)現活(huo)(huo)性炭是真(zhen)正具有延長壽命的(de)異相催(cui)化(hua)(hua)劑。
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