Hvad absorberer ved 1718 cm⁻¹ i et FTIR-spektrum?
Et bånd nær 1718 cm⁻¹ kan pege på flere funktionelle grupper. Nedenfor er de mest sandsynlige tildelinger, rangeret efter hvor meget publiceret bevis der understøtter hver — hver enkelt spores til litteratur (DOI) og krydsvalideres mod vores 130.000+ referencespektre og vidensgraf.
Backed by 8 cited sources
Hurtigt svar
Et bånd nær 1718 cm⁻¹ fortolkes normalt ved at kontrollere, hvilke funktionelle grupper der gentagne gange forekommer der i litteraturen, og derefter bekræfte mindst en eller to yderligere peaks i den samme prøve. Denne side rangerer disse tildelinger efter akkumuleret evidens snarere end efter en enkelt fast lærebogsregel.
Mulige funktionelle gruppetildelinger
| Funktionel gruppe | Understøttende fakta | Citerede kilder | Højeste tillid |
|---|---|---|---|
| Carbonyl (C=O) | 35 | 29 | 1,0 |
| Amide | 12 | 12 | 1,0 |
| Carboxyl (COOH) | 12 | 11 | 1,0 |
| Methacrylate | 12 | 10 | 1,0 |
| Acetate | 12 | 10 | 1,0 |
| Ketone | 11 | 11 | 1,0 |
| Ester | 9 | 9 | 1,0 |
| Methoxy (OCH3) | 4 | 2 | 1,0 |
| C-O single bond | 4 | 2 | 1,0 |
| Water (H2O) | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Alkyl C-H | 2 | 2 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| N h | 2 | 2 | 1,0 |
| Urethane | 2 | 2 | 0,9 |
| Acetyl | 1 | 1 | 1,0 |
| Methyl | 1 | 1 | 1,0 |
| Hydrogen bond | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Carbonate | 1 | 1 | 0,8 |
| Lignin | 1 | 0 | 0,9 |
Rangering afspejler akkumuleret litteraturevidence, ikke en enkelt fast regel. Bekræft altid mod din prøvekontekst.
Mulige materialer
| Materiale | Understøttende toppe | Overlappende grupper | Citerede kilder |
|---|---|---|---|
| Starch | 1718, 1650, 1540 | Methacrylate, Amide | 1 |
| polyurethane | 1718, 2270, 1700 | Methacrylate, Carbonyl (C=O), Amide | 1 |
| Polyester | 1718, 1700, 1250 | Carbonyl (C=O), Methacrylate, Amide | 1 |
| polymer | 1718, 1722, 1664 | Methacrylate, Carboxyl (COOH), Carbonyl (C=O) | 1 |
| cellulose | 1718, 1735, 1650 | Methacrylate, Amide | 1 |
| CA | 1718, 1045, 1650 | Methacrylate, Amide, Carboxyl (COOH) | 1 |
Materialer vises kun, når den samme litteraturpulje understøtter dette bånd og mindst en yderligere karakteristisk top.
Spektrumlogik
Dette bånd bliver meningsfuldt kun, når det læses sammen med sine nabotoppe. I praksis ser analytikere først på tildelingerne ovenfor, og kontrollerer derefter, om den samme prøve også viser andre toppe, der forventes for det samme strukturelle motiv. Et enkelt bånd nær 1718 cm⁻¹ er normalt ikke nok til materialeidentifikation alene.
Anvendelse i virkeligheden
Denne type forespørgsel er almindelig ved polymeridentifikation, screening af ukendt plast, fejlfinding i kvalitetskontrol, verifikation af genanvendt materiale og litteraturunderstøttet gennemgang af peak-tildeling.
Almindelige fejl
- Behandling af et isoleret bånd som bevis på et materiale uden at kontrollere mindst en eller to understøttende toppe.
- Ignorerer overlap: flere funktionelle grupper kan bidrage nær samme bølgetal.
- Spring validering over, når additiver, blandinger, oxidation eller forurening kan forvrænge spektret.
Verifikationsrådgivning
Når tvetydighed fortsat består, valider hypotesen med DSC, GC-MS eller TGA, især for blandinger, nedbrudte prøver og fyldte polymerer.
Litteratur bag disse tildelinger
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Amide tillid 1,0
“This region cm-1 1H types, the peak around 1718 in 2O is shifted to lower overlaps with the amide I vibrations and is dominated by cm-1 1H/2H wavenumbers by approximately 10 upon excm-1 the large negative difference signal at 1678 (see Figu”
Haas 等 - 2005 - FTIR difference spectra of Wolinella succinogenes DOI: 10.1021/bi051011d -
Alkyl C-H tillid 1,0
“follows: 3119 (N-H stretching), 3063, 2898 and 2828 (C-H (C¼O This reveals that the TP-CA cocrystal was formed after cogrinding stretching), 1718 and 1667 stretching bands), 1568 and beyond 50min.”
Solid-state thermal behavior and stability studies of theophylline–citric acid cocrystals prepared by neat cogrinding or thermal treatment DOI: 10.1016/j.jssc.2012.04.010 -
Carbonyl (C=O) tillid 1,0
“LLM confirmed rule peak-group candidate”
Lai 和 Wu - 2008 - Investigation on the conformations of AOT in water DOI: 10.1016/j.molstruc.2008.01.017 -
Amide tillid 1,0
“The proposed chemical reactions of JPUA-TDI and 1532 cm-1 and 1718 cm-1 corresponded to amide (-NH) bending and amide (-NH) stretching JPUA-IPDI are illustrated in Figure 4.”
Mudri 等 - 2020 - Comparative Study of Aromatic and Cycloaliphatic I DOI: 10.3390/polym12071494 -
Acetate tillid 1,0
“224 Presence of C=O and C-O stretch bends in the polymers was supported by the peaks at 1718 225”
Synthesis, characterization, and application of β-cyclodextrin-based ion-imprinted polymer for selective sequestration of Cr(VI) ions from aqueous media: Kinetics and isotherm studies DOI: 10.1016/j.molliq.2019.111991 -
Carbonyl (C=O) tillid 1,0
“312 this work the sum of the carbonyl peak areas of the acid, ketone, aldehyde and ester groups instead of the height of the absorbance band at 1718 cm-1 was used to calculate the CO-number.”
Thermo-Oxidative Degradation during Creep Crack Growth of PE-HD Grades as Assessed by FT-IR Spectroscopy DOI: 10.1002/masy.200451327 -
Acetate tillid 1,0
“It can be obviously detected from cm-1 1641cm-1 peaks at 1718 and which could the spectrum that the NH groups appeared at be assigned for the -C=O stretching and C=C cm-1.”
Salem 和 Salama - 2020 - Developing a New Class of UV-curable Polyurethane DOI: 10.21608/ejchem.2019.14853.1906 -
Carboxyl (COOH) tillid 1,0
“The characteristic absorption band at 1718 cm-1 would be attributed to the esterified carboxyl groups, probably created via a crosslinking cm-1”
Cellulose‐reinforced starch biocomposite: optimization of the effects of filler and various plasticizers using Design‐Expert method DOI: 10.1002/star.202000028.
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