Yeni Bir Metoksi-Substitue Schiff Bazı: Sentezi, Antioksidan Aktivitesi ve Biyodizel-Dizel Karışımlarında Termal Performansı

Yıl 2025, Cilt: 15 Sayı: 4, 1558 - 1577, 15.12.2025

Nalan Türköz Karakullukçu

https://doi.org/10.31466/kfbd.1675935

Öz

5-amino-2-metilfenol ile 5-metoksi-2-hidroksibenzaldehit’in metanol ortamında kondenzasyon reaksiyonu sonucunda (E)-2-(((3-hidroksi-4-metilfenil)imino)metil)-4-metoksifenol (HMPIM-MP) adlı yeni bir Schiff bazı sentezlendi. Bileşiğin yapısı UV-Vis, FTIR, ¹H ve ¹³C NMR spektroskopileriyle doğrulandı ve yüzey özellikleri SEM ile incelendi. Termal özellikler Termogravimetrik Analiz (TGA) ve Diferansiyel Taramalı Kalorimetri (DSC) ile değerlendirildi; serbest radikal direnci ise 2,2-Difenil-1-Pikrilhidrazil (DPPH˙) radikal süpürme deneyiyle test edildi. Bileşik 263.39 °C’de bozunmuş ve 153.69 °C’de endotermik olarak erimiş, bu da termal kararlılığını göstermektedir. DPPH˙ süpürme için IC₅₀ değeri 10.92 ± 0.80 µg/mL olup, Trolox’un 9.71 ± 0.46 µg/mL değerine yakın bulunarak güçlü antioksidan aktivite göstermiştir. Soğuk akış özelliklerini test etmek amacıyla, Schiff bazı 3000 ppm oranında B50D50 biyodizel-dizel karışımına eklenmiştir. DSC analizine göre kristalleşme sıcaklığı kontrol grubunda –9.27 °C iken, Schiff bazı katkılı karışımda –12.48 °C’ye düşmüştür. Bu sonuçlar bileşiğin hem antioksidan özellikler hem de soğuk akış iyileştirici etkiler gösterdiğini ortaya koymaktadır. Araştırma, özel olarak tasarlanmış Schiff bazlarının biyoyakıtlara eklenerek yakıt verimliliğinin sürdürülebilir şekilde artırılabileceğini önermektedir.

Anahtar Kelimeler

Schiff Bazı , Antioksidan Aktivite , Diferansiyel Taramalı Kalorimetri (DSC) , Biyodizel , Termal Stabilite

A Novel Methoxy-Substituted Schiff Base: Synthesis, Antioxidant Activity, and Thermal Performance in Biodiesel-Diesel Blends

Öz

A condensation reaction between 5-amino-2-methylphenol and 5-methoxy-2-hydroxybenzaldehyde in methanol environment yielded a novel Schiff base, (E)-2-(((3-hydroxy-4-methylphenyl)imino)methyl)-4-methoxyphenol (HMPIM-MP). The compound's structure was validated by UV-Vis, FTIR, ¹H, and ¹³C NMR spectroscopy, and its surface properties were examined using SEM. Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to analyze thermal properties, while the 2,2-Diphenyl-1-Picrylhydrazyl (DPPH˙) radical scavenging experiment investigated free radical resistance. The chemical broke down at 263.39 °C and melted endothermically at 153.69 °C, indicating thermal stability. The IC50 value for DPPH˙ scavenging was 10.92 ± 0.80 µg/mL, similar to Trolox's 9.71 ± 0.46 µg/mL, showing strong antioxidant activity. To test cold flow characteristics, the Schiff base was added to a biodiesel-diesel combination B50D50 at 3000 ppm. Crystallization temperature dropped from –9.27 °C in the control to –12.48 °C in the Schiff base mix, according to DSC. The results show the compound's antioxidant and cold flow enhancement properties. The research suggests that tailored Schiff bases may be added to biofuels to improve fuel efficiency in a sustainable way.

Anahtar Kelimeler

Schiff Base , Antioxidant Activity , Differential Scanning Calorimetry (DSC) , Biodiesel , Thermal Stability

Kaynakça

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