Industrial application of solid acid–base catalysts
TL;DR: A statistical survey of industrial processes using solid acid-base catalysts is presented in this paper, where the number of processes such as alkylation, isomerization, amination, cracking, etherification, etc.
Abstract: A statistical survey of industrial processes using solid acid–base catalysts is presented. The number of processes such as alkylation, isomerization, amination, cracking, etherification, etc., and the catalysts such as zeolites, oxides, complex oxides, phosphates, ion-exchange resins, clays, etc., are 127 and 180, respectively. The classification of the types of catalysts into solid acid, solid base, and solid acid–base bifunctional catalysts gives the numbers as 103, 10 and 14, respectively. Some significant examples are described more in detail. On the basis of the survey, the future trend of solid acid–base catalysis and the fundamental research promising for industrial success are discussed.
Citations
More filters
TL;DR: This review has summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework.
Abstract: Novel catalytic materials are highly demanded to perform a variety of catalytic organic reactions. MOFs combine the benefits of heterogeneous catalysis like easy post reaction separation, catalyst reusability, high stability and homogeneous catalysis such as high efficiency, selectivity, controllability and mild reaction conditions. The possible organization of active centers like metallic nodes, organic linkers, and their chemical synthetic functionalization on the nanoscale shows potential to build up MOFs particularly modified for catalytic challenges. In this review, we have summarized the recent research progress in heterogeneous catalysis by MOFs and their catalytic behavior in various organic reactions, highlighting the key features of MOFs as catalysts based on the active sites in the framework. Examples of their post functionalization, inclusion of active guest species and metal nanoparticles have been discussed. Finally, the use of MOFs as catalysts for asymmetric heterogeneous catalysis and stability of MOFs has been presented as separate sections.
1,115 citations
1,062 citations
961 citations
TL;DR: In this article, a 12:1 molar ratio of methanol to oil, addition of 8% CaO catalyst, 65°C reaction temperature and 2.03% water content in methanols gave the best results, and the biodiesel yield exceeded 95% at 3
Abstract: In this study, transesterification of soybean oil to biodiesel using CaO as a solid base catalyst was studied. The reaction mechanism was proposed and the separate effects of the molar ratio of methanol to oil, reaction temperature, mass ratio of catalyst to oil and water content were investigated. The experimental results showed that a 12:1 molar ratio of methanol to oil, addition of 8% CaO catalyst, 65 °C reaction temperature and 2.03% water content in methanol gave the best results, and the biodiesel yield exceeded 95% at 3 h. The catalyst lifetime was longer than that of calcined K 2 CO 3 /γ-Al 2 O 3 and KF/γ-Al 2 O 3 catalysts. CaO maintained sustained activity even after being repeatedly used for 20 cycles and the biodiesel yield at 1.5 h was not affected much in the repeated experiments.
832 citations
TL;DR: The general features of zeolites that led to their widespread use in oil refining and petrochemistry are highlighted as well as the details of their impact on selected processes.
Abstract: The general features of zeolites that led to their widespread use in oil refining and petrochemistry are highlighted as well as the details of their impact on selected processes. The analysis of the catalyst market and the position of zeolites therein is a good indication of their strategic importance. Zeolites have brought many disruptive changes to these fields (e.g. FCC). They impacted also these industries in an equally important way, although more subtle, by incremental improvement of processes. The new and vast challenges facing oil refining and petrochemistry as well as the managed transition to sustainable environmental benign transport fuel industries and chemical industries will require creative science and technologies. Zeolites offer the basis of many of these technological solutions provided efficient and balanced cooperations between industry and academia are further developed.
775 citations
References
More filters
TL;DR: In contrast to these extensive studies of heterogeneous acidic catalysts, fewer efforts have been given to the study of heterogenous basic catalysts as mentioned in this paper. But these studies have been continuous and progressed steadily, and they have never been reviewed in the chemical Reviews before.
Abstract: Heterogeneous acid catalysis attracted much attention primarily because heterogeneous acidic catalysts act as catalysts in petroleum refinery and are known as a main catalyst in the cracking process which is the largest process among the industrial chemical processes. In contrast to these extensive studies of heterogeneous acidic catalysts, fewer efforts have been given to the study of heterogeneous basic catalysts. The types of heterogeneous basic catalysts are listed in Table 1. Except for non-oxide catalysts, the basic sites are believed to be surface O atoms. The studies of heterogeneous catalysis have been continuous and progressed steadily. They have never been reviewed in the chemical Reviews before. It is more useful and informative to describe the studies of heterogeneous basic catalysis performed for a long period. In the present article, therefore, the cited papers are not restricted to those published recently, but include those published for the last 25 years. The paper first describes the generation of basic sites before describing methods used in the characterization of basic surfaces. These are indicator methods, temperature programmed desorption (TPD) of CO{sub 2}, UV absorption and luminescence spectroscopies, TPD of H{sub 2}, XPS, IR of CO{sub 2}, IR of pyrrole, and oxygen exchange betweenmore » CO{sub 2} and the surface. The paper then discusses studies on the catalysis by heterogeneous basic catalysts. Some of these reactions are dehydration, dehydrogenation, hydrogenation, amination, alkylation, ring transformation, and reactions of organosilanes. Catalysts discussed are single component metal oxides, zeolites, non-oxide types, and superbasic catalysts. 141 refs.« less
913 citations
TL;DR: In this paper, the importance of acid-base bifunctional catalysis by ZrO2 and its mixed oxides is emphasized, and industrial applications of Zr O2 catalysts are demonstrated.
Abstract: Examples of acid-base bifunctional catalysis by ZrO2 and its mixed oxides are summarized. The hydrogenation of olefins, carbon monoxide and aromatic carboxylic acids over ZrO2 are also examples of acid-base bifunctional catalysis which occur by heterolytic splitting of a hydrogen molecule (H2) into a proton (H+) and a hydride ion (H−) on the acid-base pair sites. Industrial applications of ZrO2 catalysts are demonstrated, the importance of acid-base bifunctional catalysis by ZrO2 and its mixed oxides being emphasized.
287 citations
TL;DR: In this article, high catalytic activities, selectivities and stabilities of Niobium compounds and materials and metals (Rh, Pd, Ni, Co) supported on Nb 2 O 5 are demonstrated for various reactions given in the following list of contents.
Abstract: Niobium compounds and materials such as noibium pentoxide (Nb 2 O 5 ), niobic acid (Nb 2 O 5 ·nH 2 O), niobium phosphate (NbOPO 4 ), niobium layer compounds (K 4 Nb 6 O 17 , HCa 2 Nb 3 O 10 , etc.) and mixed oxides containing niobia (Nb 2 O 5 SiO 2 , Nb 2 O 5 Al 2 O 5 , Nb 2 O 5 TiO 2 , Nb 2 O 5 V 2 O 5 , etc.) are shown to be useful as promoters and supports of catalysts and as unique solid acid catalysts, selective oxidation catalysts and photosensitive catalysts. High catalytic activities, selectivities and stabilities of these niobium compounds and materials and metals (Rh, Pd, Ni, Co, etc.) supported on Nb 2 O 5 are demonstrated for various reactions given in the following list of contents.
207 citations
TL;DR: Ferrierite is an excellent catalyst for the skeletal isomerization of n-butenes and n-pentenes, combining attractive process conditions with a high iso-olefin selectivity and a high stability as mentioned in this paper.
Abstract: Ferrierite (FER) is an excellent catalyst for the skeletal isomerisation of n-butenes and n-pentenes, combining attractive process conditions with a high iso-olefin selectivity and a high stability. This isomerisation process is now being commercialised. The excellent performance of FER is explained in this paper on the basis of the proposed reaction mechanism, combined with the product shape selectivity and the mild cracking activity of FER. The reaction mechanism for butene isomerisation might follow a route of dimerisation of butenes, skeletal isomerisation and subsequent mild and selective cracking to n- and iso-butenes. The shape selectivity of FER allows branched butene dimers in the channels, but inhibits their migration through the channels, which combined with the selective cracking, results in a low C5+ and a high isobutene selectivity.
155 citations
TL;DR: In this paper, the authors made an attempt to make an inventory of the innovative catalytic processes developed in Europe, mainly in the European Community, during the period 1980-1990, but it turned out to be impossible to consider about 70 of them, for lack of minimum information.
Abstract: This paper constitutes the result of an attempt to make an inventory of the innovative catalytic processes developed in Europe, mainly in the European Community, during the period 1980-1990. Over 160 processes were examined, but it turned out to be impossible to consider about 70 of them, for lack of minimum information. The essential of the work is constituted of tables listing new processes in (i) petroleum refining, (ii) emission control, (iii) large chemical processes and (iv) smaller chemicals processes, production of fine chemicals, and miscellaneous. This corresponds to nearly 50 processes. Some of the major innovations are discussed. In addition, we present about 40 processes which were still at the development stage in 1990. This last list indicates, perhaps better than the first ones, the push for innovation of catalytic chemistry and the direction it follows.
72 citations