Supported Lewis Acid Catalyst Research Articles

The catalytic characteristics of 2-methylnaphthalene acylation with AlCl3 immobilized on Hβ as Lewis acid catalyst

Abstract The heterogeneous supported Lewis acid catalyst prepared by immobilization technology has high reaction activity. It is an environment-friendly catalyst. Using Lewis acid immobilized as the catalyst, 2-methyl-6-propionyl naphthalene is synthesized by Friedel–Crafts reaction with 2-methylnaphthalene and propionic anhydride, which has a good development prospect. A variety of AlCl3 catalysts supported by H-zeolite molecular sieves are prepared using the solvent reflux method in the paper. It is found that AlCl3/Hβ has better catalytic performance. The results showed that AlCl3/Hβ catalyst is mainly composed of L acid. The acid content of B acid and the specific surface area increase, and the pore volume and pore size decreases. With the increase in AlCl3 concentration, the acid content of strong acid, medium strong acid, and weak acid increases, but the solubility of AlCl3 in CHCl3 is limited. When the concentration of AlCl3 is too high, too much AlCl3 is deposited on the surface of the molecular sieve, which is useless to its binding with Si–OH. AlCl3/Hβ’s activity is higher when the concentration of AlCl3 is 3 g·L−1, and the solvent is refluxed for 8 h and calcined at 550°C for 3 h. Under these conditions, the conversion of 2-methylnaphthalene is 85.86%, and the yield of β,β-methyl propyl naphthalene is increased to 81.19%.

Hosting AlCl3 on ternary metal oxide composites for catalytic oligomerization of 1-decene: Revealing the role of supports via performance evaluation and DFT calculation

Enhancing catalytic activity and stability of supported Lewis acid catalysts remain a particular challenge owing to the limited understanding and unsatisfactory tuning of the interplay between the active components and the supports. Herein, upon immobilizing AlCl3 on a series of ternary metal oxides including La2O3–Al2O3–SiO2, NiO–Al2O3–SiO2 and Ga2O3–Al2O3–SiO2, we clearly revealed the influence of the compositions and structures of the supports on the catalyst performances through experiments together with density functional theory (DFT) calculations. The catalytic performances of the supported samples were evaluated by oligomerization of 1-decene using both batch reactor and fixed-bed apparatus. The results suggest that the AlCl3 supported by NiO–Al2O3–SiO2 composites exhibits the highest catalytic activity and stability because of its positive pore structure and thereof the high loading of active species. Importantly, DFT calculations indicate that the variations of the host-guest interaction energy between the ternary oxide composites and AlCl3 are in good agreement with the experimental results. This study highlights the compositions and structures of the supports are crucial to the catalytic performances of Lewis acid catalysts, and provides fundamental guidance for design of high-performance supported catalysts.

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and X-ray photoelectron spectroscopy (XPS). XPS revealed the presence of one gallium per 2–3 styrene sulfonate groups of the polymer brushes. The catalytic activity of the Lewis acid-functionalized brushes in a microreactor was demonstrated for the dehydration of oximes, using cinnamaldehyde oxime as a model substrate, and for the formation of oxazoles by ring closure of ortho-hydroxy oximes. The catalytic activity of the microreactor could be maintained by periodic reactivation by treatment with GaCl3.

Design and performance of supported Lewis acid catalysts derived from metal contaminated biomass for Friedel–Crafts alkylation and acylation

The main goal of this work was to prove the interest of metal hyperaccumulator plants in supported Lewis acid catalysis. Friedel–Crafts alkylation and acylation reveal the great catalytic activity of different plant extracts. This approach is a green solution with chemical benefits including high yield, excellent regioselectivity, small amounts of catalyst, mild conditions and concrete perspectives towards the depletion of mineral resources. The results also constitute an incentive for the development of phytoextraction programs on metal-bearing soils.

Hydroxyapatite Supported Lewis Acid Catalysts for the Transformation of Trioses in Alcohols

We prepared hydroxyapatite-supported tin(II) chloride and tin(IV) chloride Lewis acid catalysts. These catalysts showed catalytic activity for the transformation of trioses in alcohols to yield alkyl lactates. Under optimal conditions, n-butyl lactate was obtained in 73.5% yield when dihydroxyacetone and n-butanol were treated with hydroxyapatite-supported tin(II) chloride. ： 采用浸渍法制备了羟基磷灰石 (HAP) 负载的路易斯酸 SnCl2 和 SnCl4 催化剂. 它们在三糖在醇溶液中转化为乳酸酯反应中表现出一定的催化活性. 在最佳的反应条件下, SnCl2/HAP 催化 1,3-二羟丙酮在正丁醇溶液中转化为乳酸正丁酯, 收率高达 73.5%.

Recyclable supported catalysts in microwave-assisted reactions: first Diels–Alder cycloaddition of a triazole ring

We describe here the first example in which a 1,2,3-triazole ring acts as a diene towards DMAD in microwave-assisted solvent-free Diels–Alder cycloadditions. The extrusion of a molecule of a nitrile affords pyrazole derivatives as the products. The yields can be markedly increased by using a recyclable supported Lewis acid catalyst, which can be reused at least five times without a decrease in the yield.

5607890 Supported Lewis acid catalysts derived from superacids useful for hydrocarbon conversion reactions

A supported Lewis acid catalyst system for catalyzing hydrocarbon conversion reactions including cationic polymerization, alkylation, isomerization and cracking reactions is disclosed, wherein the catalyst system comprises an inorganic oxide support having immobilized thereon a least one strong Lewis acid comprising at least one metal salt of a strong Bronsted acid wherein the metal is selected from the group consisting of aluminum, boron gallium, antimony, tantalum, niobium, yttrium, cobalt, nickel, iron, tin, zinc, magnesium barium strontium, calcium, tungsten, molybdenum and the metals of the lanthanide series and wherein the strong Bronsted acid is selected from the group consisting of mineral and organic acids stronger than 100% sulfuric acid.

Supported BF3 catalyst on crystalline polyolefins; carbocationic polymerization of isobutylene

This paper describes a new supported Lewis acid catalyst which involves BF3 species chemically bonded to the crystalline polyolefins, such as polypropylene and poly(1-butene). The supported catalysts are active in the carbocationic polymerization of isobutylene and are recovered and reused for many reaction cycles without significantly losing their activity. Several advantages, such as chemical and physical stabilities of the substrate, convenient implantation to load high concentration of catalyst to the substrate and high catalyst reactivity, have been observed. In addition, polyisobutylene obtained in this process has high terminal unsaturation.

Carbocationic polymerization of isobutylene by using supported Lewis acid catalyst on polypropylene

This paper describes a new class of supported Lewis acid catalysts which are based on partially crystalline polypropylene. The Lewis acid, such as EtAlCl2, is chemically bonded to the side chain of polypropylene and serves as catalyst for the cationic polymerization of isobutylene. This type supported catalyst can be easily recovered and reused for many reaction cycles without significant loss of its reactivity. The unique features of the structure of polypropylene offers the catalyst with high surface area and good mobility which account for the high catalytic activity. In addition, polypropylene is chemically and physically stable during the processes.

Data 1/0 PROM

Enhancing catalytic activity and stability of supported Lewis acid catalysts remain a particular challenge owing to the limited understanding and unsatisfactory tuning of the interplay between the active components and the supports. Herein, upon immobilizing AlCl3 on a series of ternary metal oxides including La2O3–Al2O3–SiO2, NiO–Al2O3–SiO2 and Ga2O3–Al2O3–SiO2, we clearly revealed the influence of the compositions and structures of the supports on the catalyst performances through experiments together with density functional theory (DFT) calculations. The catalytic performances of the supported samples were evaluated by oligomerization of 1-decene using both batch reactor and fixed-bed apparatus. The results suggest that the AlCl3 supported by NiO–Al2O3–SiO2 composites exhibits the highest catalytic activity and stability because of its positive pore structure and thereof the high loading of active species. Importantly, DFT calculations indicate that the variations of the host-guest interaction energy between the ternary oxide composites and AlCl3 are in good agreement with the experimental results. This study highlights the compositions and structures of the supports are crucial to the catalytic performances of Lewis acid catalysts, and provides fundamental guidance for design of high-performance supported catalysts.