Topic
Phosphotungstic acid
About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.
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TL;DR: In this article, 12-phosphotungstic acid supported on silica gel, zirconium sulfate, and a combination of silica gels and ZS (50% w/w) were employed as solid acid catalysts for regioselective acylation of 2-methoxynaphtalene with acetic anhydride.
Abstract: 12-Phosphotungstic acid supported on silica gel, zirconium sulfate, and a combination of silica gel and zirconium sulfate (50% w/w) were employed as solid acid catalysts for regioselective acylation of 2-methoxynaphtalene with acetic anhydride. 1-(6-Methoxynaphthalen-2-yl)ethanone (2,6-AMN), a commercially important intermediate for production of Naproxen, was obtained with excellent selectivity (>98%) at 67–68% conversion using 12-phosphotungstic acid supported on silica gel 20% (w/w) in refluxing tetrachloroethane. The unreacted starting material can be easily separated from the product by a simple crystallization from nonane.
10 citations
TL;DR: In this article, the first time Phosphotungstic acid (PTA) was used as a new catalyst for the synthesis of tetrahydroquinoline derivatives with high yields is described.
10 citations
Patent•
18 May 1983
TL;DR: In this article, a novel catalyst is formed by the combination of a heteropoly acid (e.g., phosphotungstic acid) with a carboxylic acid anhydride or chloride, in the presence of which tetrahydrofuran is polymerized to yield polytetramethylene glycol.
Abstract: PURPOSE:To obtain the titled compd. by polymn. of tetrahydrofuran without corrosion to the apparatus with a slight amt. of a catalyst under mild reacting conditions, by using the catalyst comprising a combination of a heteropoly acid with a carboxylic acid anhydride or chloride. CONSTITUTION:A novel catalyst is formed by the combination of a heteropoly acid (e.g., phosphotungstic acid) with a carboxylic acid anhydride or chloride (e.g., acetic anhydride, acetyl chloride). In the presence of the resulting novel catalyst, tetrahydrofuran is polymerized to yield polytetramethylene glycol. The amount of the heteropoly acid is 1.0-10.0wt%, pref. 1.0-5.0wt%, relative to that of tetrahydrofuran. The amount of the carboxylic acid anhydride or chloride is 10-50wt%, pref. 10-20wt%, relative to that of tetrahydrofuran.
10 citations
TL;DR: In this article, a series of organic heteropoly acidic salts with high acid strength have been prepared via the partial replacement of protons in a neat phosphotungstic acid, and these hybrid catalysts have exhibited good activity and selectivity in the benzylation of anisole with benzyl alcohol.
10 citations
TL;DR: In this paper, a trifunctional integrated catalyst with spatially intimate acidic (phosphotungstic acid (HPW)), basic (amino) and metal (Pd nanoparticles (NPs)) sites in hierarchically porous UiO-66-NH2 is presented.
Abstract: As a typical process-intensive strategy, a tandem reaction driven by a multifunctional catalyst is a paragon of the green catalytic process. Two or more active sites are usually required and their rational spatial distribution is critical for the multi-functional catalyst to act independently or synergistically. Here, we present a simple and stepwise method to construct a trifunctional integrated catalyst simultaneously with spatially intimate acidic (phosphotungstic acid (HPW)), basic (amino) and metal (Pd nanoparticles (NPs)) sites in hierarchically porous UiO-66-NH2. Through fine controlling the ratio of immobilized HPW and amino groups, we can easily tune its accessible acidic and basic properties, and the anchored HPW molecules can be effectively used to mediate the catalytic performance of Pd NPs and further stabilize the Pd sites. This well-designed integrated catalyst showed excellent catalytic activity and yield (>97%) towards one-pot three-step Deacetalization–Knoevenagel–Hydrogenation (D–K–H) catalysis reactions owing to the synergetic catalysis and the intimate spatial arrangement of the acid, basic and metal sites. More importantly, the trifunctional catalyst could be recycled at least five times without significantly losing its activity due to the strong interaction between the MOF and the guest molecules. This work provides some important insights into the construction of multifunctional integrated catalysts, especially for the application in challenging tandem catalysis.
10 citations