Cycloaddition of carbon dioxide for commercially-imperative cyclic carbonates using ionic liquid-functionalized porous amorphous silica
Cycloaddition of carbon dioxide for commercially-imperative cyclic carbonates using ionic liquid-functionalized porous amorphous silica
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DOI：
10.1016/j.apcata.2009.08.015
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发表时间：
2009-10
影响因子：
5.5
通讯作者：
S. Udayakumar;V. Raman;Hye-Lim Shim;Dae-Won Park
中科院分区：
文献类型：
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作者：
S. Udayakumar;V. Raman;Hye-Lim Shim;Dae-Won Park
以1-（三乙氧基硅丙基）-3-正烷基咪唑卤化物为原料，与正硅酸乙酯（TEOS）在强酸性条件下通过无模板剂缩合反应制备了离子液体功能化介孔氧化硅（IFMS）。通过改变共缩合方法的参数，实现了最佳的合成条件和最大的活性位点的掺入。所获得的具有0.20-0.93mmol的RIm+X-基团的无定形二氧化硅显示出477 - 672 m2/g的表面积，孔径为3.2 - 7.8nm。在不同的TEOS预水解下合成的材料具有更大的比表面积，孔体积，和平均孔径比未经预水解合成的那些。FT-IR、TG/DTG（热重/差热重）和固态核磁共振表明，所有固定化离子液体（IIL）基团都被掺入，而不影响有机部分。通过将反应性与各种参数如表面积、孔体积、孔径、活性位点的百分比、抗衡离子的类型和从烷基卤化物延伸的有机部分的长度相关联，研究了在各种二氧化碳压力下二氧化碳的化学固定。
Ionic liquid functionalized mesoporous silicas (IFMSs) were prepared from the coupling of 1-(triethoxysilylpropyl)-3-n-alkylimidazolium halides with tetraethyl orthosilicate (TEOS) through template-free condensation under strong acidic conditions. Optimal synthesis conditions and maximum incorporation of the active sites were achieved through varying the parameters of the co-condensation method. The obtained amorphous silica having 0.20–0.93mmol of RIm+X−groups showed a surface area between 477 and 672m2/g with pore sizes from 3.2 to 7.8nm. The materials synthesized under various TEOS pre-hydrolysis had larger surface areas, pore volumes, and average pore diameters than those synthesized without pre-hydrolysis. FT-IR, TG/DTG (thermogravimetry/differential thermogravimetry), and solid-state NMR showed that all the immobilized ionic liquid (IIL) groups were incorporated without affecting the organic moieties. Chemical fixation of carbon dioxide was studied at various carbon dioxide pressures by correlating reactivity with various parameters such as surface area, pore volume, pore size, percentage of active sites, type of counter ion, and length of the organic moiety extending from the alkyl halide.