One-Pot Transformation of (R)-(+)-Citronellal over a Bifunctional Ni/ZnBr2/β-Zeolite Catalyst
| Main Authors: | Khoirun Nisyak; Array, Elvina Dhiaul Iftitah; Array, Rachmat Triandi Tjahjanto; Array |
|---|---|
| Format: | Article application/pdf eJournal |
| Bahasa: | eng |
| Terbitan: |
Directorate of Research and Community Engagement, Universitas Indonesia
, 2014
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| Subjects: | |
| Online Access: |
http://journal.ui.ac.id/index.php/science/article/view/2945 |
Daftar Isi:
- Abstract The transformation of (R)-(+)-citronellal to isopulegols and menthols in a one-pot reaction was improved using a zeolite catalyst. The one-pot transformation of (R)-(+)-citronellal was studied through a Ni/ZnBr2/β-zeolite catalyst. The Ni/ZnBr2/β-zeolite catalyst was prepared by impregnating 15% ZnBr2 (w/w) and 15% Ni (w/w) on β-zeolite. The addition of Ni to the ZnBr2/β-zeolite catalyst resulted in a useful bifunctional catalyst that combined a high rate of cyclization of citronellal to isopulegols over ZnBr2 sites and subsequent hydrogenation to menthol over Ni sites. These catalysts were characterized using X-ray diffractometer (XRD) and scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDX). Catalytic reactions were carried out at 120 ºC with magnetic stirring under a 1 atm nitrogen atmosphere for 1 h (cyclization reaction) and maintained under a 1 atm hydrogen atmosphere for 4 h (hydrogenation reaction). Products of the reaction were measured using gas chromatography-mass spectrometer (GC-MS) and gas chromatography (GC). The results showed that the Ni/ZnBr2/β-zeolite catalyst can transform (R)-(+)-citronellal to isopulegols and menthols in a one-pot transformation, with a selectivity to isopulegols of 73.8% and selectivity to menthols of 6.40%. Abstrak Transformasi Satu Tahap (R)-(+)-Sitronelal Menggunakan Katalis Dwi Fungsi Ni/ZnBr2/β-zeolit. Transformasi satu tahap (R)-(+)-sitronelal menjadi isopulegol dan mentol dapat dilakukan dengan katalis berbasis zeolit. Pada penelitian ini dilakukan transformasi satu tahap (R)-(+)-sitronelal menggunakan katalis Ni/ZnBr2/β-zeolit. Katalis Ni/ZnBr2/β-zeolit dibuat dengan metode impregnasi 15% ZnBr2 (b/b) dan 15% Ni (b/b) pada β-zeolit. Penambahan Ni pada katalis ZnBr2/β-zeolit bertujuan untuk membentuk katalis dwi fungsi yang menggabungkan situs ZnBr2 untuk siklisasi sitronelal menjadi isopulegol yang dilanjutkan hidrogenasi isopulegol membentuk mentol melalui situs Ni. Katalis dikarakterisasi menggunakan X-Ray diffractometer (XRD) dan scanning electron microscope-energy dispersive X-ray spectrometer (SEM-EDX). Reaksi katalitik (R)-(+)-sitronelal dilakukan pada temperatur 120 ºC dengan pengadukan magnet dalam kondisi atmosfer gas nitrogen selama 1 jam (reaksi siklisasi) kemudian dilanjutkan pada atmosfer gas hidrogen selama 4 jam (reaksi hidrogen). Produk reaksi dianalisis menggunakan kromatografi gas-spektrometer massa (KG-SM) dan kromatografi gas (KG). Hasil penelitian menunjukkan bahwa katalis Ni/ZnBr2/β-zeolit dapat mentransformasi (R)-(+)-sitronelal menjadi isopulegol dan mentol dalam satu tahap, dengan selektivitas terhadap isopulegol sebesar 73,8% dan selektivitas terhadap mentol sebesar 6,40%. Keywords: citronellal, isopulegols, menthols, one-pot transformation, zeolite catalyst