SO4^2—／ZrO2—SiO2催化剂的制备及其对乙酸／丁醇酯化反应的催化作用

用０．５￣１．０ｍｏｌ／Ｌ Ｈ２ＳＯ４溶液处理ＺｒＯ２含量为３％￣５０％（摩尔分数）的锆硅复合氧化物，制得ＳＯ４＾２－／ＺｒＯ２－ＳｒＯ２催化剂。考察了催化剂对乙酸／丁醇酯化反应的催化作用及其制备条件（如：Ｚｒ／Ｓｉ比、沉淀剂、预焙烧温度、焙烧温度等）对催化剂性能的影响。实验结果表明，对于给定的反应，使用ＺｒＯ２含量约为１０％的ＳＯ４＾２－ＳｉＯ２催化剂时，乙酸的转化率高于９８％；而在相同条件下使     

茂金属催化乙烯聚合反应动力学

以茂金属化合物[(CH3)2C(η－C5H3）（η－C9H6）]ZrCl2为主催化剂，甲基铝氧烷MAO为助催化剂催化乙烯聚合，对不同的反应条件下（如温度，铝锆摩尔比）聚合反应的动力学进行了研究，并根据此聚合反应体系的动力学特点及考虑到活性中心的再活化，在分析和研究以往的动力学模型的基础上，对烯烃均相聚合动力学反应作了一些假定，建立了动力学模型，用模型对实验数据进行了拟合，结果表明与实验数据相吻合，可以认为，在该聚合反应体系中，确实存在铝氧烷的再活化作用，根据模拟拟合得到了聚合反应的动力学参数。     

茂金属催化剂的负载化

负载化是茂金属催化剂发展的一个新方向。本文系统地描述了茂金属负载化催化剂的主要制备方法;分析了活性中心的本质、结构以及生成机理;并且讨论了负载化对茂金属催化剂烯烃聚合性能的影响。     

修饰Al2O3负载的烯基取代茂金属催化体系催化乙烯聚合的研究

经过十几年的研究和开发,茂金属催化剂已经有了很大的发展,部分已经工业化,同时新的茂金催化体系仍然在不断地开发出来［１～４］．均相烯烃聚合催化剂经负载后能有效地改善所得聚合物的颗粒形态,并可用于气相聚合,同时也出现了许多新的聚合特征,这方面的研究一直是烯烃聚合催化剂研究领域的一个热点［５～８］．在负载型催化剂的制备时,通常用ＭＡＯ先对载体进行处理,然后再负载茂金属,这样ＭＡＯ的用量就很大．茂环上的取代基对聚合有较大的影响,许多聚合规律仍在探索之中．尽管硼化合物作为助催化剂的茂金属催化体系已经被应用…     

氧化亚锡催化酯化反应

锡的氧化物的催化作用较少报道,较成功的有使用氧化锡与氧化铬组成的二元催化剂催化氧化,氧化亚锡催化硝基苯还原及交酯的聚合。但用于催化酯化,只有用特定方     

用茂金属催化体系合成聚丙烯弹性体研究的进展

简要概括了Ｚｉｅｇｌｅｒ－Ｎａｔｔａ催化剂制备弹性聚丙烯的情况,详细综述了茂金属催化剂研究聚丙烯弹性体的新进展,并预测了今后研究的发展方向。     

一种提高茂金属载体催化剂催化性能的方法

茂金属配合物（Ｍｃ）是继Ｚｉｅｇｌｅｒ－Ｎａｔａ催化剂之后的最重要的新一代聚烯烃催化剂，尤其是１９８０年Ｋａｍｉｎｓｋｙ催化剂体系Ｃｐ２ＺｒＣｌ２／ＭＡＯ的诞生，是均相聚烯烃发展史上一次大革命。甲基铝氧烷（ＭＡＯ）作为助催化剂的催化剂体系相对于传统催...     

苯甲酸甲酯促进茂金属催化剂催化SBS加氢反应研究

以苯甲酸甲酯为促进剂,用茂金属催化剂制备了活性丁苯嵌段共聚物(SBS)的选择性催化加氢产物,讨论了苯甲酸甲酯、SBS的数均分子量等因素在几种实验条件下对产物加氢度的影响.结果表明,每百克干胶使用0.15～0.3mmol Ti催化条件下,苯甲酸甲酯在特定添加方式下能较大程度地提高茂金属催化剂的活性.在不加入苯甲酸甲酯的情况下,Mn=6.5×104和Mn=5.5×104两种SBS基础胶加氢反应180min时加氢度均97.0%;加入酯以后,反应60～120min时,基础胶的加氢度≥98%;与已报道的研究结果相比,将加氢反应时间缩短了60～120min.在每百克干胶使用0.15～0.3mmolTi催化条件下,数均分子量的大小也对SBS基础胶的加氢度有影响,反应30min时,Mn=5.5×104的加氢度≥97%,Mn=6.5×104的加氢度90%;随着反应时间的延长,这种差距在逐渐缩小;反应180min时,两者已无明显差距,此时两种基础胶的加氢度都≥98%.对影响的加氢度的机理进行了解释.     

新型层柱催化剂ZnAl-XW(11)Z的酯化催化活性

用离子交换法制备了层柱催化剂ＺｎＡｌ－ＸＷ１１Ｚ（Ｘ＝Ｐ，Ｇｅ，Ｂ和Ｃｏ：Ｚ＝Ｖ，Ｔｉ，Ｃｒ和Ｃｏ等）；ＸＲＤ和ＩＲ测试结果表明，该化合物具有通道高度为０．９９±０．０１ｎｍ的层柱的结构，层间阴离子保持Ｋｅｇｇｉｎ结构骨架；对乙酸与正丁醇的催化反应，它比ＨＹ分子筛具有更高的催化剂活性；吸附吡啶的ＩＲ测定结果表明，它同时具有有Ｂ酸和Ｌ酸两种酸性中心。     

Esterification of n-Butanol with Acetic Acid in the Presence of Heteropoly Acids with Different Structures and Compositions

The esterification reaction of n-butanol with acetic acid ([BuOH] : [HOAc] = 1 : 15 mol/mol; 55°C, 5% H₂O) was studied in the presence of tungsten heteropoly acids of the Keggin (H₃PW₁₂O₄₀, H₄SiW₁₂O₄₀, H₅PW₁₁TiO₄₀, H₅PW₁₁ZrO₄₀, and H₃PW₁₁ThO₃₉) and Dawson structure (-H₆P₂W₁₈O₆₂, H₆P₂W₂₁O₇₁(H₂O)₃, H₆As₂W₂₁O₆₉(H₂O), and H₂₁B₃W₃₉O₁₃₂). The reaction orders with respect to H₆P₂W₂₁O₇₁(H₂O)₃, H₃PW₁₂O₄₀, and H₆P₂W₁₈O₆₉are equal to 0.78, 1.00, and 0.97, respectively. It was found that the reaction rate depends on the acidity, as well as on the structure and composition of heteropoly acids. The H₂₁B₃W₃₉O₁₃₂heteropoly acid is most active, whereas the Keggin-structure heteropoly acids exhibit the lowest activities. Of the Keggin structure heteropoly acids, H₅PW₁₁ZrO₄₀exhibits the highest activity because of the presence of a Lewis acid site in its structure.     

杂多酸为催化剂的丙烯与醋酸气-液酯合成的反应模型初探

杂多酸对有机羧酸与低级烯烃的直接加成反应具有催化作用,但一般需在高压下进行。作者研究了较低压力(0.5～2.0 MPa)下的醋酸与丙烯、丁烯的加成酯化反应,结果较令人满意。本文初步探讨了醋酸与丙烯加成反应模型,为预测最佳反应条件提供了证据。     

铌酸液相催化酯化

首次以丙酸与乙醇的酯化反应为探针反应,探索了铌酸液相催化合成丙酸乙酯的适宜条件.在优化条件下,酯收率达91.5%.     

Preparation, Characterization and Catalytic Performance of La-SO42-/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation.Characterization was done by X-ray diffraction(XRD), transmission electron micrographs(TEM), nitrogen adsorption,FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials(La-SO42-/SBA-15) keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied: the molar ratio of n-butanol to acetic acid 1:1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.     

Esterification of n-Butanol with Acetic Acid in the Presence of H3PW12O40 Supported on Mesoporous Carbon Materials

The adsorption of H₃PW₁₂O₄₀ (HPA) from methanol solutions on mesoporous carbon supports (multiwall carbon nanotubes (CFC-3) and CFC modified with nitrogen atoms (N-CFC)) was studied. It was found that up to 10 wt % HPA was irreversibly adsorbed on the surface of CFC. This character of adsorption is indicative of the strong interaction of the adsorbate (HPA molecules) with coal surface groups (carboxylic, lactone, etc.) to form intermolecular hydrogen bonds with -electron interactions. It was found that N-containing surface centers affected the adsorption of HPA on N-CFC. The acid and catalytic properties of HPA/CFC systems in the esterification reaction of n-butanol with acetic acid were studied ([BuOH]/[HOAc] = 1 : 15 mol/mol; 80°C). It was found that the strength of proton centers, which was determined as proton affinity, decreased upon supporting HPA. The HPA/CFC-3 systems most actively catalyzed the reaction. The catalytic activity of HPA/N-CFC depended on the nature of N-containing groups at the support surface, and it decreased with concentration of pyridine-like structures.     

在铌酸催化剂上气相酯化反应的研究

氧化铌在含水体系中表现出强酸性,因而得到越来越多的应用。有机羧酸酯是一类重要的化工产品,一般用硫酸等作催化剂,但存在腐蚀设备等问题。我们采用铌酸催化剂进行乙醇和6种羧酸的常压气相酯化反应。实验表明,不仅乙醇转化性高,而且酯的选择率高达100％,同时,也克服了上述液体酸催化剂的缺点,有希望成为酯化反应的有效催化剂。     

Design of a Highly Efficient Indium-Exchanged Heteropolytungstic Acid for Glycerol Esterification with Acetic Acid

A series of highly active, selective, and stable solid indium-exchanged tungstophosphoric acid catalysts had been prepared, characterized and evaluated for bio-derived glycerol esterification with acetic acid to produce valuable biofuel additives. It was found that the In_x/3H_3?xPW with nanotube structure owns Lewis acidity and Brønsted acidity in one, which favors for the efficient esterification of glycerol into monoglycerides with higher selectivity. Among all, In_0.8H_0.6PW presented exceptionally high activity with 88 % conversion and 96 % selectivity to MAG within 30 min of reaction time at 120 °C using 4:1 molar ratio. The better performance came from its remarkable stability, due to the unique Keggin structure, high acidity as well as nanotube structure. In addition, this In_0.8H_0.6PW catalyst did not suffer from deactivation of water in the six consecutive reaction tests.     

新型YS类高分子铑配合物催化甲醇羰基化反应制备乙酸和乙酐

以含有两种不同配位原子的线型或交联大孔球型共聚物为配体的新型铑配合物,能在温和条件下催化甲醇羰基化为乙酸和乙酐.实验结果表明,这些新型共聚物铑配合物具有鳌合型顺-二羰基铑(Ⅰ)的结构特征,并有良好的热稳定性及高的催化活性和选择性.     

球形聚萘并噁嗪树脂酸催化酯化反应

研究了球形聚萘并GFDA1嗪树脂酸催化剂的制备方法,考察了其对酯化反应的催化活性. 萘并GFDA1嗪预聚体在甲基硅油中反相悬浮固化得到球形聚萘并GFDA1嗪树脂,再经磺化反应制得聚萘并FDA1嗪树脂酸,用扫描电子显微镜及其搭载的能谱仪(EDS)考察了催化剂的外貌特征和表面主要元素分布,用Tg分析了催化剂的热稳定性,通过催化冰醋酸与乙醇酯化反应评价了催化剂的活性. 结果表明,球形聚萘并GFDA1嗪树脂在300 ℃以下不发生热失重,45 ℃磺化得到的催化剂活性最高,树脂负载磺酸基团为4.29 mmol/g. 在反应时间2 h,催化剂用量为冰醋酸质量分数的3%和n(醇):n(酸)=2:1时,冰醋酸的转化率为77%.     

Kinetics of the Acetic Acid Oxyethylation Catalyzed by Chromium Acetate

The effect of the product of the acetic acid oxyethylation (ethylene glycol monoacetate) on the kinetics of this reaction in the presence of chromium acetate is studied. Compared to base catalysis, catalysis with chromium acetate provided a higher selectivity in the formation of the monoaddition compound. It is found that an increase in the concentration of ethylene glycol monoacetate resulted in a drop in the reaction rate. The hypothetical mechanism of catalysis is proposed. The kinetic equation that adequately describes all experimental data is derived from this mechanism.