本文選題：鎳基催化劑　切入點(diǎn)：芳香族化合物　出處：《北京化工大學(xué)》2016年碩士論文

【摘要】：芳香族化合物作為經(jīng)濟(jì)價(jià)值較高的一種化工產(chǎn)品,在各個(gè)領(lǐng)域都有著廣泛地應(yīng)用。而今,芳香族化合物多來(lái)自于石油化工行業(yè),然而隨著石油資源的日益枯竭,利用可再生的木質(zhì)素資源制備芳香族化合物具有重要的意義。在木質(zhì)素精制過(guò)程中,常用的催化劑有均相催化劑如強(qiáng)堿NaOH,負(fù)載型催化劑如Mo,Cu, Pt,Rh,Ni等,然而,這些催化劑的對(duì)C-O斷裂的選擇性比較差,且對(duì)芳環(huán)加氫能力往往過(guò)強(qiáng),得到多為經(jīng)濟(jì)價(jià)值比較低的小分子或環(huán)烷烴。所以目前由木質(zhì)素出發(fā)制取芳香族化合物的過(guò)程中主要面臨兩方面的問(wèn)題：其一,C-O鍵斷裂活性和選擇性差；其二,芳環(huán)極易深度加氫。因此,如何提高木質(zhì)素C-O鍵選擇性斷裂的同時(shí)抑制芳環(huán)的深度加氫成為該過(guò)程面臨的最大的挑戰(zhàn)。由于Ni基催化劑價(jià)格便宜,反應(yīng)條件溫和,我們針對(duì)目前負(fù)載型Ni基催化劑結(jié)構(gòu)進(jìn)行了調(diào)控,并分別用對(duì)-羥基苯基型,愈創(chuàng)木基型,紫丁香基型的木質(zhì)素模型化合物進(jìn)行催化評(píng)價(jià)。本文將通過(guò)調(diào)控活性中心金屬Ni的電子結(jié)構(gòu)和晶粒尺寸以及載體的堿性來(lái)提高Ni基催化劑對(duì)C-O鍵斷裂的活性以及選擇性,抑制對(duì)芳環(huán)深度加氫反應(yīng)。本論文研究的內(nèi)容如下：1.通過(guò)在Ni基催化劑中加入不同的金屬助劑(Zr、Sm、La)以及調(diào)變活性金屬與助劑的比例,來(lái)調(diào)控活性中心的電子結(jié)構(gòu)以及載體的堿性,以對(duì)-羥苯基型模型化合物,愈創(chuàng)木基型模型化合物,紫丁香基型模型化合物為底物,活性中心Ni的電子云密度越低,越有利于p位C-O鍵斷裂；載體的堿性越強(qiáng),越有利于α位C-O鍵斷裂。此外,活性中心Ni的電子云密度越低,更利于對(duì)芳環(huán)深度加氫的抑制。2.通過(guò)調(diào)控催化劑前體中的活性金屬含量,合成不同晶粒尺寸的Ni基催化劑,以對(duì)-羥基苯基型模型化合物為底物,催化劑的粒徑越大,活性越高,粒徑越小,對(duì)芳環(huán)深度加氫的抑制作用越強(qiáng)。
[Abstract]:Aromatic compounds as a kind of chemical products with high economic value, in various fields have been widely used. Now, aromatic compounds come from the petrochemical industry, but with the increasing depletion of oil resources, utilization of renewable resources to prepare lignin aromatic compounds has important significance in lignin refining process. In the commonly used catalysts have homogeneous catalysts such as alkali NaOH, catalysts, such as Mo, Cu, Pt, Rh, Ni and so on, however, the cleavage of the C-O selectivity of these catalysts is relatively poor, and the aromatic ring hydrogenation ability is often too strong, get more economic value low compared to small molecules or naphthenic hydrocarbon. There are mainly two aspects of problems so far by lignin preparation of aromatic compounds: the first, C-O bond cleavage activity and selectivity; second, aromatic ring hydrogenation easily. Therefore, how to improve the wood The quality of selective C-O bond breaking and inhibition of aromatic ring hydrogenation has become the biggest challenge facing the process. Because the Ni based catalyst is cheap, mild reaction conditions, we aimed at the structure of Ni based catalyst was regulated, and were p-hydroxyphenylacetate, guaiacyl, catalytic evaluation of purple syringyl type lignin model compound. In this paper, the regulation of the active center of Ni metal electronic structure and grain size as well as the basic carrier to improve Ni based catalysts for C-O bond cleavage activity and selectivity, inhibit the reaction of aromatic ring hydrogenation. The contents of this thesis are as follows: 1. by adding different metal additives in the Ni based catalyst (Zr, Sm, La) and the ratio of variable reactive metals and additives, the electronic structure and carrier to control the activity of alkaline center, to compound p-hydroxyphenyl model Guaiacyl, syringyl type model compounds, model compounds as substrate, electron cloud density of the active site of Ni is lower, more conducive to the P C-O bond cleavage; vector alkaline is stronger, more conducive to the alpha C-O bond breaking. In addition, the electron density of active center of Ni is lower, more conducive to the inhibition of.2. on aromatic ring hydrogenation by active metal content in the body of the catalysts, Ni based catalysts for the synthesis of different grain sizes, with p-hydroxyphenylacetate model compounds as substrate, the catalyst particle size is larger, the higher the activity, the smaller the particle size, the stronger the inhibition effect of aromatic ring depth hydrogenation.

【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O643.36;O625

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 宋奇;蔡嘉瑩;張俊杰;于維強(qiáng);王峰;徐杰;;Ni基催化劑上木質(zhì)素模型化合物苯基苯乙醚C O鍵的加氫裂解[J];催化學(xué)報(bào);2013年04期

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本文編號(hào)：1668482