Special Issue "Heterogeneous Acid Catalyst"

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (31 October 2018).

Special Issue Editor

Guest Editor
Prof. Dr. Michikazu Hara Website E-Mail
Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
Phone: +81-45-924-5311
Interests: heterogeneous catalysis, ammonia synthesis, hydrogenation, dehydrogenation, biomass conversion

Special Issue Information

Dear Colleagues,

Easy-separable and reusable heterogeneous acid catalysts have been playing an important role in the production of industrially important chemicals. However, much remains to be done: many heterogeneous catalytic systems are not superior to homogeneous acid catalytic systems in reaction rate and selectivity. Such problems would be solved by the improvement of conventional heterogeneous acid catalysts and processes, and new principles for surface structure, Brønsted and Lewis acid sites would also make breakthroughs in this field. This special issue on heterogeneous acid catalysts highlights recent advances not only in our understanding of catalysts, acid sites and surface structure in solid materials, but also in new possibilities of heterogeneous catalysts for industrial application. The reports on acid catalysis presented in this issue will provide a further understanding about the role of heterogeneous catalyst in environmentally benign chemical production.

Prof. Dr. Michikazu Hara
Guest Editor

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Keywords

  • Brønsted acid sites
  • Lewis acid sites
  • Acidity
  • Zeolite
  • porous material

Published Papers (5 papers)

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Research

Open AccessArticle
Use of Zirconium Phosphate-Sulphate as Acid Catalyst for Synthesis of Glycerol-Based Fuel Additives
Catalysts 2019, 9(2), 148; https://doi.org/10.3390/catal9020148 - 02 Feb 2019
Abstract
In the present work, zirconium phosphates and mixed zirconium phosphate–sulphate acid catalysts have been investigated in the acetylation of glycerol in order to obtain acetins as fuel additives. The following catalysts with chemical composition, Zr3(PO4)4, Zr(SO4 [...] Read more.
In the present work, zirconium phosphates and mixed zirconium phosphate–sulphate acid catalysts have been investigated in the acetylation of glycerol in order to obtain acetins as fuel additives. The following catalysts with chemical composition, Zr3(PO4)4, Zr(SO4)2, Zr2(PO4)2SO4, Zr3(PO4)2(SO4)3 and Zr4(PO4)2(SO4)5 have been prepared and characterized by acid capacity measurements, BET, XRD, FT-IR, XPS. The surface chemical composition in terms of P/Zr and S/Zr atomic ratios was monitored in the fresh and used catalysts. Zr3(PO4)2(SO4)3 and Zr4(PO4)2(SO4)5 showed the highest acidity associated with the synergic effect of two main crystalline phases, Zr2(PO4)2SO4 and Zr(SO4)2·4H2O. The reactions of glycerol acetylation were carried out by using a mass ratio of catalyst/glycerol equal to 5 wt% and molar ratio acetic acid/glycerol equal to 3:1. The glycerol conversion versus time was investigated over all the prepared samples in order to identify the best performing catalysts. Over Zr3(PO4)2(SO4)3 and Zr4(PO4)2(SO4)5 full glycerol conversion was achieved in 1 h only. Slightly lower conversion values were registered for Zr3(PO4)4 and Zr2(PO4)2SO4, while Zr(SO4)2 was the worst catalyst. Zr4(PO4)2(SO4)5 was the most selective catalyst and was used for recycling experiments up to five cycles. Despite a modest loss of activity, a drastic decrease of selectivity to tri- and diacetin was observed already after the first cycle. This finding was attributed to the leaching of sulphate groups as detected by XPS analysis of the spent catalyst. Full article
(This article belongs to the Special Issue Heterogeneous Acid Catalyst)
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Open AccessArticle
Performance Enhanced SAPO-34 Catalyst for Methanol to Olefins: Template Synthesis Using a CO2-Based Polyurea
Catalysts 2019, 9(1), 16; https://doi.org/10.3390/catal9010016 - 28 Dec 2018
Cited by 1
Abstract
Introducing mesopores into the channels and cages of conventional micropores CHA (Chabazite) topological structure SAPO-34 molecular sieves can effectively improve mass transport, retard coke deposition rate and enhance the catalytic performance for methanol to olefins (MTO) reaction, especially lifetime and olefins selectivity. In [...] Read more.
Introducing mesopores into the channels and cages of conventional micropores CHA (Chabazite) topological structure SAPO-34 molecular sieves can effectively improve mass transport, retard coke deposition rate and enhance the catalytic performance for methanol to olefins (MTO) reaction, especially lifetime and olefins selectivity. In order to overcome the intrinsic diffusion limitation, a novel CO2-based polyurea copolymer with affluent amine group, ether segment and carbonyl group has been firstly applied to the synthesis of SAPO-34 zeolite under hydrothermal conditions. The as-synthesized micro-mesoporosity SAPO-34 molecular sieve catalysts show heterogeneous size distribution mesopores and exhibit slightly decrease of BET surface area due to the formation of defects and voids. Meanwhile, the catalysts exhibit superior catalytic performance in the MTO reaction with more than twice prolonged catalytic lifespan and improvement of selectivity for light olefins compared with conventional microporous SAPO-34. The methodology provides a new way to synthesize and control the structure of SAPO-34 catalysts. Full article
(This article belongs to the Special Issue Heterogeneous Acid Catalyst)
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Open AccessArticle
Effect of Surface Modifications of SBA-15 with Aminosilanes and 12-Tungstophosphoric Acid on Catalytic Properties in Environmentally Friendly Esterification of Glycerol with Oleic Acid to Produce Monoolein
Catalysts 2018, 8(9), 360; https://doi.org/10.3390/catal8090360 - 28 Aug 2018
Cited by 4
Abstract
A series of protonated amino-functionalized SBA-15 materials was synthesized and tested as heterogeneous catalysts for the esterification of glycerol with oleic acid to produce monoolein. Mesoporous SBA-15 (S) was functionalized with three different aminosilanes: 3-aminopropyltriethoxysilane (N1); [3-(2-amino-ethylamino)propyltrimethoxysilane] (N2); and [...] Read more.
A series of protonated amino-functionalized SBA-15 materials was synthesized and tested as heterogeneous catalysts for the esterification of glycerol with oleic acid to produce monoolein. Mesoporous SBA-15 (S) was functionalized with three different aminosilanes: 3-aminopropyltriethoxysilane (N1); [3-(2-amino-ethylamino)propyltrimethoxysilane] (N2); and (3-trimethoxysilylpropyl) diethylenetriamine (N3), before being impregnated with 40 wt % 12-tungstophosphoric acid (HPW). The resulting nanocatalysts (S-Nx-HPW) were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption-desorption, SEM equipped with energy dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), and elemental analysis techniques. The presence of components of the nanocatalysts and the preservation of the hexagonal structure of SBA-15 were confirmed. Using different functionalizing agents considerably affected the textural properties and acidity of the synthesized nanocatalysts, which helped to improve the catalytic performance. In particular, S-N2-HPW was more active and selective than other catalysts in this study, as well as than a number of other commercial acid catalysts, with 95.0% oleic acid conversion and 60.9% monoolein selectivity being obtained after five h of reaction at 160 °C using 2.5 wt % of catalyst loading and glycerol/oleic acid molar ratio of 4:1. Aminosilane functionalization also helped to increase the reusability of the catalysts to at least six cycles without considerable loss of activity through strong electrostatic interactions between HPW anions and the protonated amino-functionalized SBA-15 materials. Full article
(This article belongs to the Special Issue Heterogeneous Acid Catalyst)
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Open AccessArticle
Co-Aromatization of n-Butane and Methanol over PtSnK-Mo/ZSM-5 Zeolite Catalysts: The Promotion Effect of Ball-Milling
Catalysts 2018, 8(8), 307; https://doi.org/10.3390/catal8080307 - 28 Jul 2018
Abstract
The ball-milling (BM) method benefits the stabilization and dispersion of metallic particles for the preparation of the PtSnK–Mo/ZSM-5 catalyst. Based on the TPR, H2-TPD, XPS, and CO-FTIR results, the Pt–SnOx and MoOx species were formed separately on the BM [...] Read more.
The ball-milling (BM) method benefits the stabilization and dispersion of metallic particles for the preparation of the PtSnK–Mo/ZSM-5 catalyst. Based on the TPR, H2-TPD, XPS, and CO-FTIR results, the Pt–SnOx and MoOx species were formed separately on the BM sample. During the aromatization of cofeeding the n-butane with methanol, the yield of the aromatics is 59 wt.% at a n-butane conversion of 86% at 475 °C over the Pt Mo BM catalyst. The more weak acid sites also contribute to the aromatics formation with the less light alkanes formation. For the Pt Ga catalysts, the slow loss of activity suggests that the BM method can restrain the coke deposition on the Pt-SnOx species, because of a certain distance between the Pt–SnOx and GaOx species on the surface of ZSM-5. Full article
(This article belongs to the Special Issue Heterogeneous Acid Catalyst)
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Open AccessArticle
A Novel High-Activity Zn-Co Catalyst for Acetylene Acetoxylation
Catalysts 2018, 8(6), 239; https://doi.org/10.3390/catal8060239 - 06 Jun 2018
Abstract
In this paper, Zn(OAc)2/AC and Zn-Co/AC catalysts were prepared and applied in an acetylene acetoxylation reaction. Compared with monometallic Zn(OAc)2/AC catalyst, which is widely applied in industry, the Zn-Co catalysts exhibited excellent catalytic performance. Transmission electron microscopy results displayed [...] Read more.
In this paper, Zn(OAc)2/AC and Zn-Co/AC catalysts were prepared and applied in an acetylene acetoxylation reaction. Compared with monometallic Zn(OAc)2/AC catalyst, which is widely applied in industry, the Zn-Co catalysts exhibited excellent catalytic performance. Transmission electron microscopy results displayed that the addition of cobalt improved the dispersity of zinc acetate particles and inhibited catalyst sintering on the catalyst surface. X-ray photoelectron spectra suggested that the Co additive changed the electron density of zinc acetate probably because of the interaction between Zn and Co species. Temperature programmed desorption analysis demonstrated Co additive strengthened the adsorption of acetic acid and weakened the adsorption of acetylene. Full article
(This article belongs to the Special Issue Heterogeneous Acid Catalyst)
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