BUHAR FAZINDA ETİL TERSİYER BÜTİL ETER (ETBE) SENTEZİNDE KULLANILAN POLİHEMA BAZLI SİLİKOTUNGSTİK ASİT KATALİZÖRLER

Yıl 2012, Cilt: 27 Sayı: 3, 0 - , 19.02.2013

Levent Değirmenci Nuray Oktar

Öz

PoliHEMA-Silikotungstik asit katalizörlerin (PH-STA) aktivitesi buhar fazında, 353-373K sıcaklık aralığında,isobüten/etanol (IB/EtOH) mol oranının 0,17 olduğu reaksiyon koşullarında gerçekleştirilen ETBE üretimi içinincelenmiştir. Çalışmada sentezlenen katalizörler varlığında IB’nin ETBE’ye dönüşümü denge dönüşümdeğerine yakın bulunmuştur. PH-STA’nın (25/75 v/v HEMA/EGDMA) 373K sıcaklık değerinde gerçekleştirilenaktivite deneyleri sonucunda dönüşüm 0,17 olarak elde edilmiştir. Belirtilen dönüşüm değerine katalizördekiaktif madde miktarı (STA) ağırlıkça %8 varlığında ulaşılmıştır. Söz konusu dönüşüm değeri öncekiçalışmalarımızda saf STA katalizörü ile elde edilen dönüşüm değerinden daha yüksektir. Katalizör dayanımıetanol ile işlem görmüş PH-STA katalizörler ile gerçekleştirilen deneyler ile test edilmiştir. TGA analizi ilesentezlenen katalizörlerin moleküler yapısının sıcaklıkla değişimi incelenmiştir. PoliHEMA’nın camsı geçişsıcaklığı (Tg) DSC analizi sonucunda 136 °C olarak belirlenmiştir. PoliHEMA ve PH-STA katalizörlerine aitFTIR ve XPS analizleri polimer yapısının oluşumunu ve yapıdaki STA’nın varlığını göstermektedir.Katalizörlerin asidik karakteri gerçekleştirilen DRIFTS analizi ile belirlenmiştir.

Anahtar Kelimeler

PoliHEMA , STA , katalizör , izobüten , ETBE.

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