孫恩浩，劉　通，閆義彬，曹媛媛，蔣　巖，趙仲陽(yáng)

(中國(guó)石油天然氣股份有限公司大慶化工研究中心，黑龍江 大慶 163714)

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綜述與展望

孫恩浩*，劉通，閆義彬，曹媛媛，蔣巖，趙仲陽(yáng)

(中國(guó)石油天然氣股份有限公司大慶化工研究中心，黑龍江 大慶 163714)

摘要：介紹固體超強(qiáng)酸催化劑的發(fā)展、特點(diǎn)、應(yīng)用及改性研究方向,研究催化劑酸強(qiáng)度低、催化劑易失活和穩(wěn)定性差等問(wèn)題,并提出解決方案。通過(guò)對(duì)國(guó)內(nèi)外/MxOy型固體超強(qiáng)酸催化劑的研究，分析向載體中引入稀土元素、分子篩、其他金屬、納米材料和交聯(lián)劑對(duì)固體超強(qiáng)酸催化劑催化活性、熱穩(wěn)定性、酸性、比表面積和晶型等的影響，綜述采用或硫酸鹽替換作為催化劑活性組分對(duì)催化劑的催化活性、酸強(qiáng)度及結(jié)構(gòu)等的影響以及引入過(guò)渡金屬(貴金屬)形成的雙官能團(tuán)對(duì)催化劑結(jié)構(gòu)與活性的影響，對(duì)制約/MxOy型固體超強(qiáng)酸催化劑研究與工業(yè)化應(yīng)用的催化劑壽命、穩(wěn)定性、機(jī)械強(qiáng)度、合成方法、催化活性及催化劑再生等問(wèn)題進(jìn)行探討。

關(guān)鍵詞：催化劑工程；固體超強(qiáng)酸/MxOy型催化劑;改性

CLC number:TQ426.6;O643.36Document code: AArticle ID: 1008-1143(2016)05-0013-06

載體是構(gòu)成催化劑的主要部分，是催化劑的骨架。通過(guò)優(yōu)化載體，提高催化劑的比表面積，增加活性中心，可提高催化活性。對(duì)載體進(jìn)行改性以增強(qiáng)催化劑的抗失活能力和機(jī)械強(qiáng)度，延長(zhǎng)催化劑使用壽命。向催化劑載體中引入新元素也具有催化作用，可進(jìn)一步提高催化劑活性[8-9]。

1.1稀土元素的引入

1.2分子篩的引入

提高催化劑的酸密度和酸強(qiáng)度可以提高催化劑的催化活性，而增大催化劑的比表面積是普遍采用的改性方法。分子篩是一種介孔型催化劑，由于比表面積大、孔徑可調(diào)、內(nèi)晶表面極化度高、吸附能力強(qiáng)且介孔材料可阻止晶粒長(zhǎng)大，形成有利于催化反應(yīng)的四方晶相結(jié)構(gòu)[12]，成為負(fù)載型催化劑的優(yōu)良載體。

Wang J A等[13]制備了Pt/H3PW12O40/Zr-MCM-41催化劑，比表面積(359.3～549.2) m2·g-1，酸性中心數(shù)量(360～481) μmol·g-1，表明催化劑酸性很強(qiáng)，催化劑活性非常高，催化劑在低溫反應(yīng)時(shí)，選擇性接近100%，在最適宜反應(yīng)溫度(280～300)℃，選擇性約90%。Brito A等[14]分別以絲光沸石和ZSM-5合成了固體超強(qiáng)酸催化劑，研究表明，提高比表面積可以提高催化劑的酸強(qiáng)度，并且有金屬骨架制備的載體可以更好的發(fā)揮協(xié)同作用使B酸受L酸影響而加強(qiáng)，與李三喜等[15]結(jié)論一致。

1.3其他載體金屬元素的引入

1.4納米材料的引入

1.5交聯(lián)劑的引入

交聯(lián)黏土是一種多微孔型材料，可通過(guò)金屬氧化物(如Al2O3、ZrO2等)或復(fù)合金屬氧化物(如Al2O3-Ga2O3等)進(jìn)行合成，該合成物質(zhì)具有較大的比表面積，在(500～700)℃穩(wěn)定性很好，由于交聯(lián)黏土本身具有一定量的酸性，且對(duì)以酸性中心為活性的反應(yīng)有加強(qiáng)作用，適用于異構(gòu)化反應(yīng)和加氫裂解反應(yīng)。Rachid Issaadi等[24]用蒙脫土(M)、鋯(Zr)和硫酸(S)合成了Zr-MS并負(fù)載Pd，制備Pd/Zr-MS催化劑，Zr-M的比表面積為247 m2·g-1，未復(fù)合Zr黏土的BET比表面積為95 m2·g-1，表明合成的載體具有更好的比表面積，可以提供更多催化活性吸附位。浸漬硫酸負(fù)載酸性組分的過(guò)程，使催化劑具有催化活性，但催化劑的孔結(jié)構(gòu)被改變，比表面積減至135 m2·g-1，孔容增大，并得到較好的酸強(qiáng)度。以異丙醇脫水反應(yīng)為探針，丙烷的最初生成速率為16×105mol·(s·g)-1，然后逐漸降低75%的速率，這是由于催化劑表面積炭覆蓋了活性中心，降低了催化活性，需要對(duì)催化劑進(jìn)行再生。

2活性組分的改性

固體超強(qiáng)酸催化劑的活性組分為酸性中心，通過(guò)催化劑中L酸和B酸以協(xié)同的方式表現(xiàn)出來(lái)，以異構(gòu)化為例，酸性中心可以催化正構(gòu)烷烴重排異構(gòu)化為異構(gòu)烷烴，酸強(qiáng)度在一定程度上決定了催化劑的催化活性，故采用酸強(qiáng)度高和穩(wěn)定性好的酸性組分對(duì)催化劑進(jìn)行改性，制得高活性催化劑。

3過(guò)渡金屬的引入

4結(jié)語(yǔ)與展望

今后的研究方向?yàn)椋?1) 催化劑機(jī)械強(qiáng)度研究，可以減少催化劑的孔道塌陷和孔道堵塞，延長(zhǎng)其使用壽命；(2) 催化劑合成方法研究，提高催化劑的制備效率和比表面積，改善催化劑的結(jié)構(gòu)，從綠色化工角度優(yōu)化催化活性；(3) 解決催化劑的再生循環(huán)問(wèn)題，提高催化劑再生后的催化效率，實(shí)現(xiàn)催化劑的重復(fù)利用。

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Sun Enhao*, Liu Tong, Yan Yibin, Cao Yuanyuan, Jiang Yan, Zhao Zhongyang

(Daqing Petrochemical Research Center of PetroChina, Daqing 163714, Heilongjiang, China)

Abstract:The development,characteristics,application and modification of solid superacid catalysts were introduced.The existing problems of low acid strength,easy deactivation and poor stability of the catalysts,etc. were investigated,and the solutions were put forward.Through the research of domestic and international /MxOy solid superacid catalysts,the effects of rare earth element introduction,molecular sieves,other carrier metals,nano materials,and crosslinking agents on catalytic activity,thermal stability,acidity,surface area and crystal type of solid superacid catalysts were analyzed.Substituting or sulfate for ,the influence of or sulfate as the activity components of the catalysts on catalytic activity,acid strength and structure of the catalysts,and the effects of the introduction of transition metals (precious metals) formed the bifunctional catalysts on structure and catalytic activity of the catalysts were reviewed.The problems such as catalyst life,stability,mechanical strength,synthesis methods,catalytic activity and catalyst regeneration,which restricted the research on and commercial application of solid superacid catalysts,were discussed.

Key words:catalyst engineering; solid superacid; /MxOy catalyst; modification

收稿日期：2015-11-03；修回日期：2016-03-29

作者簡(jiǎn)介：孫恩浩,1989年生,男，黑龍江省大慶市人，碩士，工程師，研究方向?yàn)楣I(yè)催化。

doi:10.3969/j.issn.1008-1143.2016.05.003 10.3969/j.issn.1008-1143.2016.05.003

中圖分類號(hào)：TQ426.6;O643.36

文獻(xiàn)標(biāo)識(shí)碼：A

文章編號(hào)：1008-1143(2016)05-0013-06

通訊聯(lián)系人：孫恩浩。