發(fā)布時(shí)間：2018-12-19 11:34

【摘要】：生物質(zhì)固體炭磺酸自2004年出現(xiàn)開(kāi)始已然成為固體酸催化劑中的研究熱點(diǎn)。炭磺酸的催化穩(wěn)定性主要依賴于其炭骨架結(jié)構(gòu)以及活性中心的穩(wěn)定性。提高炭磺酸的機(jī)械性能,研究活性中心穩(wěn)定性降低的原因可以為進(jìn)一步改進(jìn)催化劑穩(wěn)定性提供新方法,為實(shí)現(xiàn)炭磺酸的工業(yè)化生產(chǎn)提供基礎(chǔ)研究。以廢棄樟樹(shù)枝原料制備了樟木炭磺酸,并通過(guò)官能團(tuán)屏蔽的方法對(duì)其酸性官能團(tuán)在環(huán)氧環(huán)己烷的甲醇解反應(yīng)中的作用進(jìn)行了探究。炭磺酸上磺酸基團(tuán)是本反應(yīng)的主要催化活性中心,羧酸官能團(tuán)具有較弱的催化活性,而酚羥基沒(méi)有活性,但酚羥基的存在能提高炭磺酸的催化性能。根據(jù)反應(yīng)動(dòng)力學(xué)結(jié)果,弱酸性官能團(tuán)對(duì)反應(yīng)的促進(jìn)作用是通過(guò)促進(jìn)反應(yīng)底物在催化劑表面的吸、脫附過(guò)程來(lái)實(shí)現(xiàn)的。以竹屑為原料制備了竹炭磺酸,分別以環(huán)己酮縮乙二醇的合成和環(huán)氧環(huán)己烷的甲醇解考察了竹炭磺酸在有水參與的反應(yīng)體系和無(wú)水反應(yīng)體系中催化活性降低的原因。炭磺酸催化活性降低是因?yàn)槠浠钚灾行幕撬峁倌軋F(tuán)的喪失:在合成環(huán)己酮縮乙二醇的反應(yīng)中磺酸根水解和成酯是磺酸量下降的原因,在環(huán)氧環(huán)己烷的甲醇解反應(yīng)中則主要是因?yàn)榛撬岣某甚シ磻?yīng)。采用氫離子交換和再次磺化的方法可恢復(fù)催化劑活性。以竹材加工過(guò)程中產(chǎn)生的廢棄竹塊為原料,通過(guò)減壓炭化-甲醛處理-磺化的方法制備了抗磨損強(qiáng)度較大的炭磺酸催化劑。建立了磨損強(qiáng)度測(cè)試的方法,對(duì)甲醛處理提高竹炭磺酸磨損強(qiáng)度的制備條件進(jìn)行了優(yōu)化。磨損強(qiáng)度相比于未經(jīng)甲醛處理制備的炭磺酸的磨損強(qiáng)度得到了很大的提高。炭化產(chǎn)物與甲醛溶液和40 wt%硫酸比(m:V:V)為4:20:1,處理溫度40℃,處理時(shí)間8 h,竹炭磺酸的磨損率可降低至4.03%。而同條件下未用甲醛處理的竹炭磺酸磨損率為25.28%。
[Abstract]:Biomass solid carbon sulfonic acid has been a hot research topic in solid acid catalysts since its appearance in 2004. The catalytic stability of carbon sulfonic acid mainly depends on the structure of carbon skeleton and the stability of active center. Improving the mechanical properties of carbon sulfonic acid and studying the reason of decreasing the stability of active center can provide a new method for further improving the stability of catalyst and provide basic research for realizing the industrial production of carbon sulfonic acid. Cinnamomum camphora charcoal sulfonic acid was prepared from the waste camphor branch and the role of acid functional group in methanol hydrolysis of cyclohexane was investigated by functional group shielding method. The sulfonic group on the carbon sulfonic acid group is the main catalytic active center in this reaction. The carboxylic acid functional group has weak catalytic activity, but the phenolic hydroxyl group has no activity. However, the presence of phenol hydroxyl group can improve the catalytic activity of carbon sulfonic acid. According to the results of reaction kinetics, the promotion of weakly acidic functional groups to the reaction is achieved by promoting the adsorption and desorption of the substrate on the surface of the catalyst. Bamboo charcoal sulfonic acid was prepared from bamboo chips. The reasons for the decrease of catalytic activity of bamboo charcoal sulfonic acid in aqueous and anhydrous reaction systems were investigated by synthesis of cyclohexanone glycol and methanol hydrolysis of cyclohexane respectively. The decrease in catalytic activity of carbon sulfonic acid is due to the loss of the sulfonic functional group of its active center: the hydrolysis and esterification of sulfonic acid in the synthesis of cyclohexanone ethylene glycol are the reasons for the decrease in sulfonic acid content. The methanol hydrolysis of cyclohexane is mainly due to the esterification of sulfonic acid. The catalyst activity can be restored by hydrogen ion exchange and re-sulfonation. The carbon sulfonic acid catalysts with high wear resistance were prepared by decompression carbonization formaldehyde treatment and sulfonation from the waste bamboo blocks produced in the process of bamboo processing. The wear strength test method was established and the preparation conditions of formaldehyde treatment to improve the wear strength of bamboo charcoal sulfonic acid were optimized. Compared with the carbon sulfonic acid prepared without formaldehyde treatment, the wear strength of carbon sulfonic acid was greatly improved. The ratio of carbonized product to formaldehyde solution and 40 wt% sulfuric acid (m:V:V) was 4: 20: 1, treatment temperature was 40 鈩，

本文編號(hào)：2386865