Methyl — FTIR-absorptions-toppe og tildelinger

Hurtigt svar

Methyl 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 Methyl

Viser de 30 bedst understøttede toppe ud af 463 i alt for Methyl.

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

• 2927 cm⁻¹ tillid 1,0

  “The stretching of hydroxyl group (─OH) of starch was presented by a peak at 3291 cm-1 whereas the starch methyl group at 3291cm-1 2927 cm-1.”

  Ashri 等 - 2018 - Modified Dioscorea hispida starch-based hydrogels DOI: 10.1016/j.ijbiomac.2017.10.125
• 1142 cm⁻¹ tillid 1,0

  “42 43 cm-1 In the spectrum of PMMA, there is a distinct absorption band at 1142 which is due to O-CH 3 44”

  Ataei 等 - 2020 - Electrosprayed PMMA microcapsules containing green DOI: 10.1088/1361-665X/ab9754
• 1420 cm⁻¹ tillid 1,0

  “Only the green group cm-1 showed to have peak located at ~1420 which is assigned for C-H bending of methyl, and”

  Azlah 等 - 2020 - A fast and reliable 2D-IR spectroscopic technique DOI: 10.1016/j.vibspec.2019.103014
• 2920 cm⁻¹ tillid 1,0

  “cm-1 compounds remained The peaks at 2920 and 2840 correspond to C-H stretching of methyl and methylene62.”

  Physicochemical characterisation of barley straw treated with sodium hydroxide or urea and its digestibility and in vitro fermentability in ruminants DOI: 10.1038/s41598-022-24738-w
• 1509 cm⁻¹ tillid 1,0

  “In both cases the characteristic absorption bands are showed: 1509 and 1608 cm-1 (C=C bonds of aromatic ring), 1457 cm-1 (CH2 group vibration), 1362 cm-1 (methyl group vibration) and”

  Barbadillo 等 - 2003 - Study of a curing reaction of an epoxy resin DOI: 10.4028/www.scientific.net/MSF.426-432.2163
• 1234 cm⁻¹ tillid 1,0

  “C-O-C stretching in esters 1234 (w) 1232 (w) 1242 (w) CH3 bending 1379 (w)”

  Barnaby 等 - 2018 - Free Radical Scavenging Capacity, Carotenoid Conte DOI: 10.1155/2018/1762342
• 1264 cm⁻¹ tillid 1,0

  “The peak at 1264 Phytonanocomposite indicates the presence of strong methyl bond.”

  Synthesis of Phytonanocomposite of Zinc Oxide by Ixora coccinea Linn for Cancer Treatment DOI: 10.1007/s10904-016-0382-y
• 500 cm⁻¹ tillid 1,0

  “The exothermic peak at 500 by hydrolytically stable -Si-(CH 3) groups present in HMDS corresponds to the critical temperature of -(CH 3) groups at 3 3 and TMCS, according to the chemical reactions (2) and (3) which they get oxidized leaving”

  Bhagat 等 - 2007 - Rapid synthesis of water-glass based aerogels by i DOI: 10.1016/j.apsusc.2006.07.016