Esterification of acetic acid with ethanol: Reaction kinetics and operation in a packed bed reactive distillation column

The reaction kinetics of the esterification of acetic acid with ethanol, catalyzed both homogeneously by the acetic acid, and heterogeneously by Amberlyst 15, have been investigated. The reactions were carried out at several temperatures between 303.15 and 353.15 K and at various starting reactant compositions. Homogeneous and heterogeneous reactions have been described using the models proposed by Pöpken et al. [T. Pöpken, L. Götze, J. Gmehling, Reaction kinetics and chemical equilibrium of homogenously and heterogeneously catalyzed acetic acid esterification with methanol and methyl acetate hydrolysis, Ind. Eng. Chem. Res. 39 (2000) 2601–2611]. These models use activities instead of mole fractions. Activity coefficients have been calculated using ASOG [K. Kojima, K. Tochigi, Prediction of Vapor–liquid Equilibria by the ASOG Method, Elsevier, Tokyo, 1979] and UNIFAC (Aa. Fredenslund, J. Gmehling, P. Rasmussen, Vapor–liquid Equilibria Using UNIFAC. A Group Contribution Method, Elsevier, Amsterdam, 1977] methods.

A packed bed reactive distillation column filled with Amberlyst 15 has been employed to obtain ethyl acetate. The influence of feed composition and reflux ratio have been analyzed.     

A Kinetic Study of Sunflower Oil Methanolysis Catalyzed by Barium Hydroxide

Methanolysis of sunflower oil was investigated in the presence of barium hydroxide as a catalyst. It was observed that the methanolysis reaction was both heterogeneously and homogeneously catalyzed. The heterogeneously catalyzed reaction is faster than the homogeneously catalyzed one and determines the overall reaction rate. Under optimum reaction conditions, a very high fatty acid methyl ester content was obtained within a few minutes. The barium hydroxide‐catalyzed methanolysis is faster than the methanolysis catalyzed by calcium oxide and calcium hydroxide and comparable to the potassium hydroxide‐catalyzed methanolysis.     

Methyl formate as a new building block in C1 chemistry

Methyl formate has been proposed as a building block molecule in C₁ chemistry. This paper examines the potential of this concept by reviewing the processes of synthesis of the molecule and the chemical reactions that it undergoes. Methyl formate can be produced by a variety of routes from a number of feedstocks. The reaction between methanol and carbon monoxide is an efficient process, used commercially. Combination of an efficient synthesis of methyl formate and its facile decomposition allows the molecule to be used as a means for separation, storage and transport of synthesis gas. The number of reactions that convert methyl formate to other chemicals is large. In particular, the synthesis of large volume chemicals such as methanol, acetic acid and ethylene glycol deserves serious consideration. Examples are provided of applications in the chemical and energy industries involving methyl formate. The reactions involved in the synthesis and transformation of methyl formate are mostly catalytic in nature. Many currently known catalytic systems are not efficient to compete with conventional routes involving methanol or synthesis gas. Fundamental research to understand the catalytic chemistry involved is highly desirable in order to improve the performance of the catalytic systems.     

Synthesis of Biodiesel through Catalytic Transesterification of Various Feedstocks using Fast Solvothermal Technology: A Critical Review

The fossil fuel reserves are depleting at a more rapid rate as a result of the population growth and the ensuing energy utilization. Biodiesel is a mixture of fatty acid methyl esters produced from the transesterification of plant oils or animal fats. Moreover, the source of raw materials and manufacturing costs have become the major hurdle in the commercialization of biodiesel; thus, alternative sources such as the use of waste oils and non-edible oils together with biodiesel production techniques have long been considered. Selecting an appropriate feedstock and increasing production yield are two important approaches to decrease the costs of biodiesel production. Typically, biodiesel, which operates with electrical or conventional heating to generate high efficiency of the product, consumes a huge amount of power in a long reaction time. In contrast, chemical reactions speed up by microwave irradiation which results in producing high yields of product in a shorter chemical reaction time. In this extensive article, an effort has been made to review the use of microwave technology including multi-feedstock and recent studies on microwave-assisted heterogeneously catalyzed processes for biodiesel production. The heterogeneous catalyst performance has also been covered, including the measurement of their pysico-chemical properties. The microwave irradiation used for the synthesis of biodiesel is also included. In addition, the reaction variables impacting the transesterification process, such as heating system, microwave power, type and amount of heterogeneous catalyst, oil/methanol molar ratio, reaction time, temperature and mixing intensity, are covered. The final part of this article will cover the details of previously performed work on heterogeneous catalysts. Finally, energy balances for the traditional and microwave-based processes, conclusions, and recommendation on the topic are presented. The aim this article is to focus on recent studies on microwave-assisted heterogeneously catalyzed processes.     

Verwendung von Kohlendioxid bei technischorganischen Synthesen

Use of carbon dioxide in industrial organic syntheses . Although carbon dioxide is important as an abundant carbonaceous raw material, its utilization in chemical processes so far has been rather limited. This review covers the reactions of CO₂ employed in industry, such as the production of urea, the Kolbe-Schmitt reaction, the synthesis of cyclic organic carbonates, and the use of CO₂ in methanol synthesis. Interesting recent developments in CO₂ chemistry, especially the transition metal catalyzed reactions, are also elucidated. In addition to the synthesis of polymers and hydrocarbons, the production of oxygen-containing chemicals seems to be very profitable and attractive for future industrial applications. Not only can derivatives of formic acid and carbonic acid be formed but longer-chain carboxylic acids and their derivatives are also accessible by reactions of carbon dioxide with hydrocarbons such as alkynes, alkenes, and 1,3-dienes.     

羟基乙叉二膦酸合成新方法的研究

HEDP(羟基乙叉二膦酸)是一种用途广泛的工业水处理剂。合成原料中的三氯化磷易分解成氯化氢气体,污染环境。本文主要研究以亚磷酸替代三氯化磷为原料合成HEDP。实验结果表明,以亚磷酸、醋酸、十二烷基磺酸钠为原料,合成HEDP的相对最佳工艺条件为:m[H3PO3]:m[CH3COOH]:m[CH3(CH2)11SO3Na]=10:4:1,反应温度为:112℃,保温反应6小时。合成的产品基本符合HEDP的质量要求。     

Homogene oder heterogene Katalyse? Simultane Verwendung von basischen und sauren Zeolithen in der flüssigen Phase bei der Umesterung und Veresterung

Base catalyzed transesterification of triglycerides with methanol was studied in liquid phase on a K-LSX zeolite. The presence of free fatty acid results in its deactivation. Their esterification was catalyzed by an acidic H-Y zeolite. Surprisingly, in case of mixing of both catalysts, no catalytic activity was observed. Consequently, both reactions should proceed homogeneously because the formation of the intermediate methylat ion is suppressed. This could be explained in term of a fast ion exchange between the K⁺ ions of K-LSX and the H⁺ ions of Y-zeolite. On the other hand, the observed transport limitation indicates on a heterogeneously catalyzed reaction. Therefore, in case of even non-aqueous liquid phase reactions, a contribution of a homogeneous reaction path must be considered.     

Fe2O3-CuO/ZSM-5催化剂催化低浓度瓦斯制甲醇

采用催化氧化的方法,将煤矿抽采瓦斯制成高价值的化学品或液体燃料甲醇是其综合利用的一个发展方向。寻找对瓦斯转化具有较好的催化效果,且能替代贵金属催化剂的普通催化剂是瓦斯催化氧化制甲醇的研究重点。本文以硝酸铁、硝酸铜和ZSM-5分子筛为原料,采用离子交换法制备了Fe₂O₃/ZSM-5、CuO/ZSM-5和Fe₂O₃-CuO/ZSM-5催化剂,并在乙酸溶剂中考察了3种催化剂催化低浓度瓦斯部分氧化合成甲醇的性能。结果表明,Fe₂O₃/ZSM-5、CuO/ZSM-5和Fe₂O₃-CuO/ZSM-5对瓦斯部分氧化制甲醇反应均有催化活性,但Fe₂O₃-CuO/ZSM-5的催化效果最明显,且Fe、Cu负载量对催化剂的催化活性影响较为显著,Fe和Cu的最佳理论负载量分别为4.21%和3.22%。在Fe₂O₃-CuO/ZSM-5(x_Fe=4.21%,x_Cu=3.22%)添加量为0.1g、乙酸溶剂用量30mL的条件下,Fe₂O₃-CuO/ZSM-5催化甲烷体积分数为20%配制瓦斯制甲醇的最佳反应条件为初始反应压力4.0MPa、反应温度200℃、反应时间3h。     

Experimentelle und theoretische Betrachtungen der Methanol- und direkten DME-Synthese im Labor- und Technikums-Maßstab

Engineering of strongly exothermic heterogeneously catalyzed reactions to industrial size is challenging. Synthesis of methanol and direct dimethyl ether synthesis serve as example for such type of reactions and related experimental results are described. Results from laboratory as well as technical scale are provided. The experiments show the variation of two main operational parameters: reaction temperature and CO₂ content at reactor inlet.     

低压羰基合成醋酸装置中甲醇加入量的控制与应用

利用自动化控制技术对低压羰基合成醋酸装置中甲醇加入量进行精确控制,避免甲醇的过量加入,有效提升反应转化率,降低醋酸生产成本。     

The Catalytic Hydrogenation of Carbon Monoxide. The Formation of C1 Hydrocarbons

Both the production of methane and methanol from CO and H₂ are important processes in chemical technology. They also have a distinguished history as the formation of methane was first reported by Sabatier and Senderens [1] in 1902. Methanol synthesis from CO and H₂ was first reported by Patart [2] in 1921, and in 1923 Badische Anilin and Soda Fabrik (BASF) announced the synthesis of CH₃OH to the exclusion of other products [3]. The catalytic reactions that produced these two molecules, however, have been subjected to molecular scale studies only recently. We shall review here what is known about the kinetics and mechanisms of these reactions, about the catalytically active surface, and the nature of the surface chemical bond of CO, H₂, and the reaction intermediates.     

合成气的工业应用与催化剂研究进展

详细介绍了合成气制备液体燃料、低碳烯烃、含氧化合物和其他化学品的工业应用情况,同时,综述了其工业应用中所使用的催化剂研究进展和新型催化剂的开发情况,并指出今后应进一步推进实用技术,加快工业化。     

甲醇羰基化

以煤为原料生产甲醇，然后经碳一化工路线生产有机化工产品，是我国煤炭资源和能源利用的发展方向之一。甲醇羰基化可以生产醋酸、醋酐、醋酸乙烯、甲酸甲酯、碳酸二甲酯等多种化工产品。本文介绍甲醇低压碳基化生产醋酸、甲酸甲酯、甲醇氧化羰化合成碳酸二甲酯的生产方法和工艺路线。     

An Experimental Test of Various Models of the Active Site for Nitric Oxide Reduction on Platinum

In 1925, H. S. Taylor [1] hypothesized that a heterogeneously catalyzed reaction occurs predominantly at a few distinct places on the catalyst's surface called “active sites.” Many models of the active site have been proposed [1–32] over the years. However, at present there is little agreement about what causes the active sites to have special catalytic properties.     

大型煤气化技术的研究与发展

煤气化技术是煤炭清洁高效转化的核心技术,是发展煤基化学品合成（氨、甲醇、乙酸、烯烃等）、液体燃料合成（二甲醚、汽油、柴油等）、先进的IGCC发电系统、多联产系统、制氢、燃料电池、直接还原炼铁等过程工业的基础,研究和开发大型煤气化具有重要意义。本文概述了国外大型煤气化技术发展的主要情况,介绍了国内大型煤气化技术研究开发的现状和产业化情况,分析了煤气化技术大型化的主要趋势与应该采取的技术途径。     

NHD脱硫脱碳技术在醋酸生产中的应用综述

NHD脱硫、脱碳技术具有能耗低、净化度高、设备和流程简单等特点,已在合成氨、甲醇生产企业的脱硫、脱碳中得到了成功应用,并取得了丰富的实践经验.文章介绍了NHD脱硫脱碳在兖矿国泰化工有限公司醋酸生产方面的应用,经该技术净化后的煤气质量优良,有效的保护了醋酸合成催化剂.因此NHD脱硫脱碳技术在以煤为原料合成醋酸的煤气净化中的应用是成功的.     

An Experimental Test of Various Models of the Active Site for Nitric Oxide Reduction on Platinum

In 1925, H. S. Taylor [1] hypothesized that a heterogeneously catalyzed reaction occurs predominantly at a few distinct places on the catalyst's surface called “active sites.” Many models of the active site have been proposed [1-32] over the years. However, at present there is little agreement about what causes the active sites to have special catalytic properties.     

Catalytic Generation of Hydrogen from Formic acid and its Derivatives: Useful Hydrogen Storage Materials

In this account the concept of using formic acid as a hydrogen storage material is presented. Catalytic reduction of carbon dioxide and heterogeneously catalyzed decomposition of formic acid to hydrogen and carbon dioxide are briefly discussed. In the main part the historic development and recent examples of homogeneously catalyzed hydrogen generation from formic acid are covered in detail.     

Catalytic cascade acetylation-alkylation of biofuran to C17 diesel precursor enabled by a budget acid-switchable catalyst

Lignocellulosic biomass is a promising feedstock for the synthesis of value-added chemicals and biofuels. However, one of the biggest challenges for producing high-quality diesel fuels is the lack of sufficient carbon-chain length in biomass derivatives. In this study, a C17 diesel precursor 1,1,1-tris(5-methyl-2-f uryl)ethane (TEMF) with a yield of ca. 70% was synthesized from the cascade acetylation-hydroxyalkyla tion/alkylation of bio-based 2-methylfuran (MF) with acetic anhydride (AA) catalyzed by acid-treated montmorillonite with enhanced acidity and improved porosity. The catalytic mechanism of the cascade reaction process was investigated over different types of acid species (Brønsted acid and Lewis acid), and the influence of in situ formed acetic acid was also examined. A synergistic effect was observed to enable the synthesis of TEMF from the trimerization of MF with AA, in which Lewis acid and weak Brønsted acid species mainly catalyze the acetylation and hydroxyalkylation processes, while the subsequent alkylation step is mainly catalyzed by strong Brønsted acid.     

电石与醇的反应行为

在高压釜中研究了电石与甲醇、乙醇和异丙醇的反应行为及反应温度、反应时间和催化剂对产物的影响,通过设计对比实验,探索了电石与醇的反应途径。结果表明,电石与醇的反应产物包括乙炔、乙烯基醚、醇钙和醇钙分解产生的醇。乙烯基醚的生成途径除了文献报道的电石与醇的直接反应外,还包括电石与醇反应生成醇钙和乙炔、乙炔再与醇反应形成乙烯基醚的两步机理。