Thermal features of radiation induced radical of gamma irradiated gallic acid

Year 2017, Volume: 19 Issue: 1, 51 - 59, 12.06.2017

Hasan Tuner Mehmet Oktay Bal

https://doi.org/10.25092/baunfbed.321019

Cited By: 1

Abstract

In the present work,
temperature effects of gamma irradiated anhydrous and monohydrate gallic acid
components were investigated using Electron Paramagnetic Resonance (EPR)
spectroscopy.  While unirradiated samples
presented no EPR signal, irradiated samples were observed to exhibit an EPR
spectrum consisting of an intense resonance line at the middle and weak lines
on both sides.  Thermal features of the
radicals responsible of experimental EPR spectrum were explored trough the
variations of the peak-to-peak amplitude and spectrum area under the EPR
spectra.  Also the high temperature
annealing stability of the radicals was investigated.  It is calculated that the activation energies
of the main two radicals that contributed to the experimental spectra of GA-a
and GA-m compounds was 64.68 kJ/mol and 88.11 kJ/mol, and 35.88 kJ / mol and
127.64 kJ/mol, respectively.

Keywords

Electron Paramagnetic Resonance (EPR), gallic acid, irradiation, thermal features

Gama radyasyonu ile ışınlanan gallik asitte oluşan radikallerin termal özellikleri

Abstract

Bu çalışmada sıcaklığın, gama radyasyonu sonucunda gallik asit anhydrous
(GA-a) ve gallik asit monohydrate (GA-m) bileşenlerine olan etkisi Elektron
Paramanyetik Rezonans (EPR) spektroskopisi kullanılarak incelenmiştir.  Işınlanmamış
örneklerde herhangi bir EPR sinyali gözlenmezken, ışınlanmış örnekler merkezde
ve her iki tarafında yer alan bir EPR spektrumu verdiği gözlenmiştir.  Deneysel EPR spektrumuna kaynaklık eden
radikallerin termal özellikleri tepeden-tepeye sinyal şiddeti ve spektrum
altında kalan alan dikkate alınarak araştırılmıştır.  Ayrıca radikallerin yüksek sıcaklıkta tavlama
sonucunda radikallerin kararlılığı araştırılmıştır.  GA-a ve GA-m örneklerinin deneysel
spektrumlarına katkı getiren iki ana radikalin aktivasyon enerjileri sırasıyla
64.68 kJ/mol ve 88.11 kJ/mol, ve 35.88 kJ/mol ve 127.64 kJ/mol olduğu
hesaplanmıştır.

Keywords

Elektron Paramanyetik Rezonans (EPR), gallik asit, ışınlama, termal özellikler

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