以正丁胺为模板剂合成SAPO-34及其在氨甲基化反应中的应用（英文）

发布时间：2018-05-18 10:05

本文选题：SAPO-分子筛 + 正丁胺　；参考：《催化学报》2017年03期

【摘要】：以正丁胺为模板剂首次合成了纯相的SAPO-34分子筛.考察了硅投料量、硅源种类以及晶化温度等条件对所得样品性质的影响.发现反应温度为200°C时,不加入硅源,合成产物为磷酸铝层状相kanemite;加入硅溶胶后,产物中开始有SAPO-34晶体出现,且随着硅投料量的增加,kanemite逐渐消失,SAPO-34分子筛成为主要产物,最终在Si O2/Al2O3摩尔比为0.6-1.4时得到纯相的SAPO-34.不同的硅源对SAPO-34产品的形貌和尺寸影响较大.反应温度为160°C时,合成体系中无法晶化得到SAPO-34,当提高至240°C后,由于层状相在高温下不能稳定存在,此时可以在较宽的硅投料区间内合成得到纯相SAPO-34产品.在200和240°C时,考察了使用同样的初始凝胶合成SAPO-34样品的晶化过程.发现在200°C时,合成体系中最初大量生成了kanemite,随后逐渐减少,SAPO-34晶体开始生成并最终成为唯一产物.而在240°C时,无机原料很快被溶解,之后大量的SAPO-34晶体快速生成,产物的收率和相对结晶度迅速增加,且整个晶化过程中并无层状相生成.这再次证明了高温对层状相的生成有着明显的抑制作用,因此提高晶化温度可以成为一种有效调节产品晶相的方法,特别是在容易产生层状相杂质的合成体系中.鉴于胺热合成方法的诸多优点,例如较高的收率、较好的吸附分离及催化反应效果,几种伯胺(正丁胺、正丙胺、环己胺)被用于充当模板剂和溶剂来合成得到了SAPO分子筛产品.其中,正丙胺为一种新的合成SAPO-34的模板剂.对SAPO-34产品进行X射线衍射、X射线荧光分析、扫描电镜、N_2物理吸附、NH_3程序升温脱附、热重和固体核磁共振等表征.结果显示,得到的SAPO-34产品具有很好的结晶度、孔结构以及合适的酸性.使用氨甲基化反应对正丁胺合成的SAPO-34进行催化反应评价.结果显示,该样品对甲胺和二甲胺具有很高的择形选择性,是一种具有潜在前景的甲胺合成催化剂.
[Abstract]:Pure phase SAPO-34 molecular sieve was synthesized with butylamine as template for the first time. The effects of the amount of silicon feed, the type of silicon source and the crystallization temperature on the properties of the samples were investigated. It is found that when the reaction temperature is 200 掳C, the synthesized product is aluminum phosphate layered phase kanemite without adding silicon source, and the SAPO-34 crystal appears in the product after adding silica sol, and SAPO-34 molecular sieve becomes the main product with the increase of silicon dosage. Finally, the pure phase SAPO-34 was obtained when the molar ratio of Si O2/Al2O3 was 0.6-1.4. Different silicon sources have great influence on the morphology and size of SAPO-34 products. When the reaction temperature is 160 掳C, SAPO-34 can not be crystallized in the synthesis system. When the reaction temperature is raised to 240 掳C, the layered phase can not exist stably at high temperature, so pure phase SAPO-34 products can be synthesized in a wide range of silicon feeding range. At 200 掳C and 240 掳C, the crystallization process of SAPO-34 samples synthesized by the same initial gel was investigated. It was found that at 200 掳C, a large number of kanemite was formed in the synthesis system, and then gradually decreased the crystal formation of SAPO-34 and finally became the only product. However, at 240 掳C, the inorganic raw materials were dissolved quickly, after which a large number of SAPO-34 crystals were rapidly formed, the yield and relative crystallinity of the products increased rapidly, and no layered phase was formed in the whole crystallization process. It is proved that the high temperature can inhibit the formation of layered phase obviously, so increasing the crystallization temperature can become an effective way to adjust the crystal phase of the product, especially in the synthesis system where the lamellar impurity is easy to be produced. In view of the advantages of the thermal synthesis of amines, such as higher yields, better adsorption, separation and catalytic reactions, several primary amines (n-butylamine, n-propylamine, n-butylamine, n-propylamine) Cyclohexylamine) is used as a template and solvent for the synthesis of SAPO molecular sieve products. Among them, n-propylamine is a new template for the synthesis of SAPO-34. The SAPO-34 products were characterized by X-ray diffraction X-ray fluorescence analysis, thermal gravimetric analysis and solid nuclear magnetic resonance (NMR). The results show that the SAPO-34 product has good crystallinity, pore structure and suitable acidity. The catalytic reaction of SAPO-34 synthesized by n-butylamine was evaluated by ammonia methylation. The results showed that the sample had high form-selective selectivity for methylamine and dimethylamine and was a potential catalyst for the synthesis of methylamine.
【作者单位】：中国科学院大连化学物理研究所甲醇制烯烃国家工程实验室;中国科学院大学;
【基金】：supported by the National Natural Science Foundation of China(21676262,21476228,21506207) the Key Research Program of Frontier Sciences of CAS(QYZDB-SSW-JSC040)~~
【分类号】：O643.36

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