Matches in SemOpenAlex for { <https://semopenalex.org/work/W657663100> ?p ?o ?g. }
Showing items 1 to 82 of
82
with 100 items per page.
- W657663100 endingPage "230" @default.
- W657663100 startingPage "219" @default.
- W657663100 abstract "A ternary-mixed oxide catalyst, H3PO4-WO3-Nb2O5, was prepared with the evacuation of a mixed solution of phosphoric acid, niobic oxalate, and (NH4)10W12O41, followed by calcination in air. We found that the oxide catalyst (Cat-A) exhibited excellent activity in the Friedel-Crafts alkylation. The recycle use of the catalyst was possible through separation of the oxide by filtration. Interestingly, the catalytic performance was remarkably sensitive to the calcination temperature, and the temperature of 773 K was found to be the optimum condition. On the basis of 31P NMR studies, formation of the Nb-containing heteropoly acid, H4PNbW11O40, was observed at the preparation procedure. The active species was derived from the heteropoly acid as a result of the partial decomposition at 773 K. The evolution of novel acidity with relatively strong character was observed in the temperature programmed desorption of ammonia. The amount of the novel acidity was in good correlation with the catalytic performance. The catalytic activity was much improved by using H4PNbW11O40 as the precursor for the preparation of the catalyst (Cat-B). The catalyst exhibited high activity in the Friedel-Crafts acylations using carboxylic acids as well, in which a flow-type reaction was also possible over a period of 7 days. Further improvement in the catalytic activity and thermal stability was achieved by using a Nb-containing Dawson-type HPA (H9P2Nb3W15O62) as the precursor for preparation of the SiO2-loaded catalyst. In particular, the catalyst became insoluble even in hot water when it was calcined at 743 K. Based on the IR, EXAFS and 31P NMR studies, the active species was obtained through the removal of Nb atoms from the Dawson-type structure on the SiO2 support." @default.
- W657663100 created "2016-06-24" @default.
- W657663100 creator A5070105971 @default.
- W657663100 date "2009-01-01" @default.
- W657663100 modified "2023-10-05" @default.
- W657663100 title "Active Catalyst Derived from Nb-containing Heteropoly Acids: Their Acid Properties and Catalysis in Friedel-Crafts Reactions" @default.
- W657663100 cites W1969078587 @default.
- W657663100 cites W1977716045 @default.
- W657663100 cites W1979447671 @default.
- W657663100 cites W2012499383 @default.
- W657663100 cites W2028804811 @default.
- W657663100 cites W2039569237 @default.
- W657663100 cites W2055992535 @default.
- W657663100 cites W2063233133 @default.
- W657663100 cites W2064568517 @default.
- W657663100 cites W2069763450 @default.
- W657663100 cites W2072390729 @default.
- W657663100 cites W2079094867 @default.
- W657663100 cites W2128435160 @default.
- W657663100 cites W2129474151 @default.
- W657663100 cites W2149030056 @default.
- W657663100 cites W2170145383 @default.
- W657663100 cites W2951066945 @default.
- W657663100 cites W2951202178 @default.
- W657663100 doi "https://doi.org/10.1627/jpi.52.219" @default.
- W657663100 hasPublicationYear "2009" @default.
- W657663100 type Work @default.
- W657663100 sameAs 657663100 @default.
- W657663100 citedByCount "5" @default.
- W657663100 countsByYear W6576631002013 @default.
- W657663100 crossrefType "journal-article" @default.
- W657663100 hasAuthorship W657663100A5070105971 @default.
- W657663100 hasBestOaLocation W6576631001 @default.
- W657663100 hasConcept C13965031 @default.
- W657663100 hasConcept C161790260 @default.
- W657663100 hasConcept C175583648 @default.
- W657663100 hasConcept C178790620 @default.
- W657663100 hasConcept C179104552 @default.
- W657663100 hasConcept C185592680 @default.
- W657663100 hasConcept C202224193 @default.
- W657663100 hasConcept C2776351790 @default.
- W657663100 hasConcept C2776622989 @default.
- W657663100 hasConcept C2778077586 @default.
- W657663100 hasConcept C2779851234 @default.
- W657663100 hasConcept C2779990138 @default.
- W657663100 hasConcept C2781047139 @default.
- W657663100 hasConcept C7082614 @default.
- W657663100 hasConceptScore W657663100C13965031 @default.
- W657663100 hasConceptScore W657663100C161790260 @default.
- W657663100 hasConceptScore W657663100C175583648 @default.
- W657663100 hasConceptScore W657663100C178790620 @default.
- W657663100 hasConceptScore W657663100C179104552 @default.
- W657663100 hasConceptScore W657663100C185592680 @default.
- W657663100 hasConceptScore W657663100C202224193 @default.
- W657663100 hasConceptScore W657663100C2776351790 @default.
- W657663100 hasConceptScore W657663100C2776622989 @default.
- W657663100 hasConceptScore W657663100C2778077586 @default.
- W657663100 hasConceptScore W657663100C2779851234 @default.
- W657663100 hasConceptScore W657663100C2779990138 @default.
- W657663100 hasConceptScore W657663100C2781047139 @default.
- W657663100 hasConceptScore W657663100C7082614 @default.
- W657663100 hasIssue "5" @default.
- W657663100 hasLocation W6576631001 @default.
- W657663100 hasOpenAccess W657663100 @default.
- W657663100 hasPrimaryLocation W6576631001 @default.
- W657663100 hasRelatedWork W185945221 @default.
- W657663100 hasRelatedWork W1971607745 @default.
- W657663100 hasRelatedWork W2007976646 @default.
- W657663100 hasRelatedWork W2019528796 @default.
- W657663100 hasRelatedWork W2048667985 @default.
- W657663100 hasRelatedWork W2057523466 @default.
- W657663100 hasRelatedWork W2067550605 @default.
- W657663100 hasRelatedWork W2087160045 @default.
- W657663100 hasRelatedWork W2386549840 @default.
- W657663100 hasRelatedWork W4298008856 @default.
- W657663100 hasVolume "52" @default.
- W657663100 isParatext "false" @default.
- W657663100 isRetracted "false" @default.
- W657663100 magId "657663100" @default.
- W657663100 workType "article" @default.