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"Asam levulinat merupakan salah satu produk bahan kimia unggulan yang berasal dari biomassa lignoselulosa. Permintaan asam levulinat dunia meningkat sekitar 4% setiap tahunnya menjadikan asam levulinat masuk dalam klasifikasi 12 jenis bahan kimia building block berbasis bio- dan diperlukan oleh industri makanan, farmasi, kecantikan, dan bahan bakar. Proses utama proses produksi asam levulinat adalah hidrolisis biomassa menjadi gula sederhana dengan bantuan katalis homogen jenis asam mineral. Penggunaan asam mineral memberikan yield hingga 70%, namun dinilai memiliki kelemahan dari sisi lingkungan dan proses rekoveri katalis. Beberapa kandidat katalis homogen telah diujicoba dalam proses konversi biomassa menjadi asam levulinat, seperti katalis polimer, logam oksida, serta campuran logam oksida dan zeolit. Dalam penelitian ini, substrat bahan baku yang digunakan adalah biooil berbasis kayu pinus yang mengandung levoglucosan sebesar 35%. Proses konversi dengan hidrotermal katalitik dilakukan pada kondisi subkritis air yaitu 250-340oC dengan variasi dua jenis katalis yaitu zeolit alam Sukabumi teraktivasi dan zeolit komersial H-ZSM-5. Hasil penelitian menunjukkan terjadi pembentukan asam levulinat tertinggi diperoleh dari proses hidrotermal pada temperatur 280oC. Perhitungan yield asam levulinat dilakukan dengan basis levoglucosan yang terkandung di dalam biooil dan diperoleh hasil untuk katalis H-ZSM-5 dan CANZ-5 masing-masing sebesar 19,50% dan 14,85%.

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Levulinic acid is one of the superior chemical products derived from lignocellulosic biomass. The demand for levulinic acid is expected to increase 4% annually and it is classified as one of the top 12 promising bio-based building blocks for supporting the food, pharmaceutical, beauty and fuel industries. Levulinic acid is produced by biomass hydrolysis into simple sugar and homogeneous catalyst such as acid mineral. The utilization of mineral acid gives higher yield until 70%, but it is harm to our environment and having problem in recovery process. Some of heterogeneous catalyst have beed explored in the converting process of biomass to levulinic acid, such as polymer catalyst,

metal oxides and other mixture of metal oxide and zeolites. In this study, the pinewood biooil with 35,46% levoglucosan were used in converting process with catalytic hydrothermal process in subcritical water condition. There are two types catalysts carried out to the process, activated Sukabumi natural zeolite and commercial zeolite H-ZSM- 5. The reaction temperature taken at 280oC showed a great yield both in H-ZSM-5 and CANZ-5. The levoglucosan-based calculation gave the levulinic acid yield for H-ZSM- 5 and CANZ-5 were 19,50% and 14,85%, respectively."

"Titanium (IV) dioksida atau TiO2 adalah senyawa yang banyak diaplikasikan dalam berbagai bidang katalis karena sifatnya yang tidak berbahaya bagi lingkungan dan inert. Salah satu aplikasi TiO2 dalam bidang kimia adalah pemanfaatannya sebagai katalis penyangga karena memiliki luas permukaan yang besar, dan mudah dilakukan modifikasi dengan adanya penambahan logam. Pada penelitian ini TiO2 telah disintesis ke dalam bentuk nanowires menggunakan metode molten salt. TiO2 nanowires yang telah disintesis kemudian dimodifikasi dengan penambahan logam perak melalui metode impregnasi basah, untuk mendapatkan katalis Ag2O/TiO2 nanowires yang stabil dan memiliki aktivitas katalitik tinggi, serta ramah lingkungan. Pada penelitian ini, Ag2O/TiO2 nanowires yang telah disintesis, dianalisis karakteristiknya menggunakan XRD, TEM, SEM, UV-Vis DRS, XPS, serta spektroskopi raman, dan didapatkan hasil katalis memiliki struktur kristal rutile, struktur morfologi nanowires, dengan ukuran rata-rata diameter Ag2O sebesar 20,377 nm di permukaan TiO2. Katalis Ag2O/TiO2 nanowires sejumlah 0,0035 gram kemudian diaplikasikan pada 0,5 M NaBH4 untuk reaksi reduksi 0,003125 M 4-nitrophenol menjadi 4-aminophenol. Dari hasil aplikasi tersebut, didapatkan waktu konversi 4-nitrophenol menjadi 4-aminophenol selama 5 menit pada kondisi suhu ruang, konversi ini ditandai dengan perubahan warna dari kuning menjadi bening.

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Titanium (IV) dioxide or TiO2 is a compound that is widely applied in various catalyst fields because of its nature which is not harmful to the environment and inert. One of TiO2 application in chemistry is its use as a buffer catalyst because it has a large surface area, and is easily modified by addition of metals. In this research, TiO2 has been synthesized into the form of nanowires using the molten salt method. The synthesized TiO2 nanowires are then dispersed with silver metal through the wet impregnation method, to obtain a stable catalyst Ag2O/TiO2 nanowires that have high catalytic activity, and are environmentally friendly. This research will conduct a study of the characteristics of the catalyst Ag2O/TiO2 nanowires using XRD, TEM, SEM, UV-Vis DRS, XPS, and raman spectroscopy. The catalyst result had a rutile crystal structure nanowires morphological structure, with an average size Ag2O diameter of 20,377 nm on the surface of Catalyst Ag2O/TiO2 nanowires in the amount of 0,0035 grams was then applied to 0,5 M NaBH4 for the reduction reaction of 0,003125 M 4-nitrophenol to 4-aminophenol. From the results of the application, conversion time of 4-nitrophenol to 4-aminophenol obtained for 5 minutes, this conversion is characterized by a change in color from yellow to clear."

"[ABSTRAKKonversi bentuk nanopartikel perak (AgNP) melalui pemanasan dan fotoinduksi terjadi dengan kehadiran sitrat sebagai capping agent dan polivinilpirolidone (PVP) sebagai stabilisator. Awalnya, assintesis nanoprisma perak (AgNP-Biru) dipanaskan selama 30 menit hingga terbentuk nanodisk perak (AgNP-Kuning). Selanjutnya, di bawah penyinaran lampu natrium nanoprisma perak(AgNP-Iradiasi) kembali terbentuk dengan ukuran yang lebih besar. Spektrofotometer UV-Vis dan transmission electron microscopy (TEM) digunakan untuk investigasi pertumbuhan dan konversi bentuk AgNP. Hasil penelitian menunjukkan bahwa parameter kisi AgNP-orange (4.0716 Å) lebih kecil dari AgNP-Iradiasi (4.3134 Å). Hal tersebut mengindikasikan terjadinya rearrangement atom perak pada permukaan AgNP. AgNP dengan bentuk bulat dan triangular diuji akivitas katalitiknya sebagai katalis homogen dan heterogen untuk reduksi 4-nitrofenol. Sebagai katalis heterogen, AgNP diimobilisasi dalam karbon aktif dan dikarakterisasi menggunakan SEM-EDX. Aktivitas katalitik AgNP-Iradiasi lebih aktif daripada AgNP-Orange. Konstanta kinetika reaksi pseudo orde satu reduksi 4-NP dengan NaBH4 adalah 0.2178 s-1 (katalis homogen) dan 0.2225 s-1 (katalis heterogen).

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ABSTRACTHeated and Photoinduced shape conversion of silver nanoparticles (AgNPs) were occurred in the presence of citrate as capping agent and polyvinylpyrrolidone (PVP) as additional stabilizer. First, the as-synthesized silver nanoprism (AgNP-Blue) were heated to transformed into silver nanodisks (AgNP-Orange) with time. Subsequently, under light irradiation (sodium lamp), an increasing fraction of silver nanoprism (AgNP-Irradiation) develop. The UV-Vis spectrophotometer and transmission electron microscopy (TEM) were adopted to investigate the growth and shape conversion of AgNPs. The result show that the lattice constant of AgNP-Orange converted by heating (4.0716 Å) less than AgNP-Irradiarion (4.3134 Å), which was possibly achieved through rearrangement of silver atoms on the surface of AgNPs. Both silver nanodisk and nanoprism were tested as homogenous and heterogeneous catalyst for reduction of 4-nitrophenol (4-NP). AgNPs supported on activated carbon were synthesized as heterogen catalyst and characterized by SEM-EDX. For catalytic application, AgNP-Irradiation were more actived than AgNP-orange. The kinetic constants of pseudo first orde reaction of reduction 4-NP with NaBH4 are 0.2178 s-1 for homogeneous and 0.2225 s-1 for heterogeneous catalyst, Heated and Photoinduced shape conversion of silver nanoparticles (AgNPs) were occurred in the presence of citrate as capping agent and polyvinylpyrrolidone (PVP) as additional stabilizer. First, the as-synthesized silver nanoprism (AgNP-Blue) were heated to transformed into silver nanodisks (AgNP-Orange) with time. Subsequently, under light irradiation (sodium lamp), an increasing fraction of silver nanoprism (AgNP-Irradiation) develop. The UV-Vis spectrophotometer and transmission electron microscopy (TEM) were adopted to investigate the growth and shape conversion of AgNPs. The result show that the lattice constant of AgNP-Orange converted by heating (4.0716 Å) less than AgNP-Irradiarion (4.3134 Å), which was possibly achieved through rearrangement of silver atoms on the surface of AgNPs. Both silver nanodisk and nanoprism were tested as homogenous and heterogeneous catalyst for reduction of 4-nitrophenol (4-NP). AgNPs supported on activated carbon were synthesized as heterogen catalyst and characterized by SEM-EDX. For catalytic application, AgNP-Irradiation were more actived than AgNP-orange. The kinetic constants of pseudo first orde reaction of reduction 4-NP with NaBH4 are 0.2178 s-1 for homogeneous and 0.2225 s-1 for heterogeneous catalyst]"

"The application of bio-oil for biofuel has been limited due to its low heating value, high acidity and high oxygenate content. pursuant to the urgency of obtaining access to sustainable energy from renewable resources, the studies for bio-oil upgrading have been recently placed in high priority. this study is aimed at identifying the effect of biomass types on bio-oil product characteristics. the conversion of several types of biomass, i.e. rice straw, rubberwood (hevea brasiliensis), and palm empty fruit bunches (efb) to bio-oil by-products was investigated in a catalytic fast pyrolysis (cfp) reactor using a ni/zsm-5 nickel nitrate and zeolite catalyst at 550oc and at atmospheric pressure. the results show that ni/zsm-5 catalyst has actively enhanced the de-oxygenation reaction process and aromatic production. the composition of aromatic compounds in bio-oil from rubberwood, rice straw, and efb are 10.25 wt%, 7.8 wt%, and 5.98 wt%, respectively. in the absence of a catalyst, bio-oil from rice straw contains no aromatics."

"CuO/TS-1 catalysts have been prepared and tested in the benzene hydroxylation. TS-1 was synthesized by hydrothermal method, while CuO/TS-1 was prepared by impregnation method using Cu(NO)2. 3H2O as precursor. Catalysts were characterized by using X-ray diffraction (XRD), infrared spectroscopy (IR), and N2 adsorption-desorption techniques. The catalytic activity was tested in the hydroxylation reaction of benzene. The products were analyzed using gas chromatography. Catalyst characterization by XRD and IR techniques have showed that the catalyst structure was a MFI type of zeolite. XRD pattern have showed the orthorombic structure and indicated the presence of CuO aggregation. The results of the pyridine adsorption have found that the acidity of TS-1 and CuO/TS-1 were a Lewis acid and it?s increased with an increasing amount of CuO loading. The results of nitrogen adsorption analysis have showed decreasing of surface areas of catalyst with increasing amount of CuO loading. The optimum conditions of benzene hydroxylation was observed by 1%CuO/TS-1 catalyst at 70 °C, reaction time 2 h and acetic acid as the solvent yielded 27.6% of phenol with phenol selectivity was 75.5%"

"ABSTRAKSebagian biomassa pertanian menghasilkan yang dapat digunakan sebagai sumber energi alternatif. Salah satu biomassa yang melimpah di Indonesia adalah jerami padi, saat ini jerami dibiarkan membusuk, ditumpuk dan dibakar. Jerami padi mengandung lignoselulosa tinggi sehingga dapat digunakan sebagai bahan baku untuk memproduksi sikloheksena. Cyclohexene adalah bahan baku yang sering digunakan dalam pembuatan nilon. Penelitian ini dilakukan untuk menghasilkan sikloheksen dari jerami padi sebagai bahan baku dengan variasi komposisi katalis dan suhu. Komposisi katalis dan suhu mempengaruhi nilai konversi dan produksi sikloheksena, penting untuk menggunakan kombinasi yang tepat dan suhu untuk menghasilkan sikloheksen dengan konsentrasi maksimum. Metode yang digunakan adalah pirolisis dan catalytic cracking. produk cair dari pirolisis dimasukkan ke dalam reaktor katalitik dikonversi menjadi sikloheksen daripada dianalisis dengan isinya senyawa dengan Gas Chromatography (GC-MS).

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ABSTRAKMost agriculture produce biomass that can be used as an alternative energy source. One of the biomass that is abundant in Indonesia is rice straw, nowadays the straw left to rot, piled and burned. Rice straw contains high lignocellulose so that it can be use as a raw material for producing cyclohexene. Cyclohexene is a raw material often used in the manufacture of nylon. This study is done to produce cyclohexene from rice straw as raw material with variation of catalyst composition and the temperature. The composition of the catalyst and temperature affects the value of the conversion and production of cyclohexene, it is important to use the right combination and temperature in order to produce cyclohexene with maximum concentration. The method use is pyrolysis and catalytic cracking. Liquid products from pyrolysis are incorporated into the catalytic reactor converted into cyclohexene than it is analyzed by its content of compounds with Gas Chromatography (GC-MS)."