Lewis acid site — FTIR-absorptions-toppe og tildelinger
Dette er de karakteristiske FTIR-bølgetal, hvor Lewis acid site har tendens til at absorbere, samlet fra publiceret litteratur og rangeret efter understøttende bevis. Hver tildeling kan spores til en kilde (DOI) og krydsvalideres mod vores 130.000+ referencespektre og vidensgraf.
Backed by 8 cited sources
Hurtigt svar
Lewis acid site tildeles normalt ved at lede efter en tilbagevendende klynge af karakteristiske toppe frem for et præcist lærebogsnummer. Tabellen nedenfor viser, hvor litteraturen oftest placerer denne gruppe i FTIR, rangeret efter akkumuleret evidens.
Karakteristiske FTIR-toppe for Lewis acid site
| Bølgetal (cm⁻¹) | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| 1445 | 4 | 3 | 1,0 |
| 1545 | 4 | 2 | 1,0 |
| 1455 | 3 | 0 | 1,0 |
| 1540 | 2 | 2 | 1,0 |
| 1605 | 2 | 2 | 1,0 |
| 1490 | 2 | 1 | 1,0 |
| 1449 | 1 | 1 | 1,0 |
| 1393 | 1 | 1 | 1,0 |
| 1442 | 1 | 1 | 1,0 |
| 2306 | 1 | 1 | 1,0 |
| 1575 | 1 | 1 | 1,0 |
| 1650 | 1 | 1 | 1,0 |
| 2275 | 1 | 1 | 1,0 |
| 2272 | 1 | 1 | 1,0 |
| 2295 | 1 | 1 | 1,0 |
| 1438 | 1 | 1 | 1,0 |
| 1495 | 1 | 1 | 1,0 |
| 2166 | 1 | 1 | 1,0 |
| 1456 | 1 | 1 | 1,0 |
| 1444 | 1 | 1 | 1,0 |
| 1454 | 1 | 1 | 1,0 |
| 1614 | 1 | 1 | 1,0 |
| 1453 | 1 | 1 | 1,0 |
| 1642 | 1 | 1 | 1,0 |
| 1635 | 1 | 1 | 1,0 |
| 2322 | 1 | 1 | 1,0 |
| 1606 | 1 | 1 | 1,0 |
| 1489 | 1 | 1 | 1,0 |
| 3733 | 1 | 1 | 1,0 |
| 3786 | 1 | 1 | 1,0 |
Viser de 30 bedst understøttede toppe ud af 45 i alt for Lewis acid site.
Spektrumlogik
En funktionel gruppetildeling bliver mere sikker, når flere forventede bånd optræder sammen. Brug denne side til at finde de bedst understøttede peaks, og bekræft derefter, at den samme prøve udviser et sammenhængende mønster snarere end et enkelt isoleret hit.
Anvendelse i virkeligheden
Disse sider er nyttige til analyse af ukendte materialer, topforklaring i rapporter, polymerfejlfinding og verifikation af, om en kandidatmaterialefamilie er kemisk plausibel.
Almindelige fejl
- Brug af én funktionel-gruppe-side som en komplet materialebedømmelse uden at kontrollere resten af spektret.
- Antager, at det stærkeste bånd altid er det mest diagnostiske.
- At glemme, at forarbejdning, tilsætningsstoffer, ældning og blandinger kan flytte eller udvide forventede toppe.
Verifikationsrådgivning
Brug DSC, GC-MS eller TGA, når flere materialefamilier deler lignende bånd, eller når blandings-effekter gør FTIR-tildelingen usikker.
Litteratur bag disse tildelinger
-
1605 cm⁻¹ tillid 1,0
“remains above 473 K can most likely be attributed to the as- (cid:228) to 1288 while the peak at 1605 shifts to 1588 (NH 3) coordinated to Lewis acid sites that are still adsorbed on Both of these peaks remain, even as the temperature is in”
Pena 等 - 2004 - Identification of surface species on titania-suppo DOI: 10.1021/jp0313122 -
1700 cm⁻¹ tillid 1,0
“Both catalysts showed several cm-1, Brönsted and Lewis acid sites due to the interaction between iridabsorption bands at 1700, 1680, 1650, and 1640 which are ium and lattice defects or extra-lattice oxygen.”
IR study of iridium bonded to perturbed silanol groups of Pt-HZSM5 for n-pentane isomerization DOI: 10.1016/j.apcata.2011.12.039 -
1490 cm⁻¹ tillid 1,0
“The spectra also show a band at 1490 150 common to a vibration mode of pyridine coordinated to the catalysts' Lewis acid sites and”
TiO2 Catalyzed Dihydroxyacetone (DHA) Conversion in Water: Evidence That This Model Reaction Probes Basicity in Addition to Acidity DOI: 10.3390/molecules27238172 -
1540 cm⁻¹ tillid 1,0
“The typical bands resulting from pyridine adsorbed on Brønsted acid sites sites (PyH+) are observed around 1540 cm-1, while the bands from pyridine interacting with Lewis (PyH+ cm-1, ) are observed around 1540 while the bands from pyridine”
Bellmann 等 - 2020 - Determining the Location of Co2+ in Zeolites by UV DOI: 10.3390/catal10010123 -
3786 cm⁻¹ tillid 1,0
“The shouldering near 3786 and the band at are assigned to CO adsorbed on strong cm(cid:1)1 cm(cid:1)1 3770 Lewis acid sites.”
Benkhaled 等 - 2006 - Synthesis of highly dispersed palladium alumina su DOI: 10.1016/j.apcata.2006.06.011 -
1489 cm⁻¹ tillid 1,0
“cm-1) contained both bands of pyridine coordinated to Lewis sites (1608, 1489 and 1446 and pyridinium cations formed by reaction of pyridine with Brønsted sites (1640, 1547 and 1489 cm-1).”
Unravelling water effects on solid acidic catalysts: Case study of TiO 2 /SiO 2 for dehydration of isobutanol DOI: 10.1016/j.jcat.2016.12.007 -
2322 cm⁻¹ tillid 1,0
“The concentration of Brønsted and Lewis sites were obtained cm-1 365 from the integral intensities of the IR bands of adsorbed CD 3CN at 2296 and 2322 cm-1, 366 respectively, by using the extinction factor coefficients reported in Section 2”
New synthesis routes and catalytic applications of ferrierite crystals. Part 1: 1,8-Diaminooctane as a new OSDA DOI: 10.1016/j.micromeso.2019.109987 -
1635 cm⁻¹ tillid 1,0
“In contrast, the ratio of the acid were nated to the Lewis acid sites and the bands at 1635 and 1545 Brønsted Brønsted sites concentration to the total and Lewis acid sites concenattributed to pyridine bounded to the acid sites.”
Fedyna 等 - 2020 - Composite of PtAlSBA-15+zeolite catalyst for the DOI: 10.1016/j.micromeso.2020.110366
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