Garuda - Garba Rujukan Digital

PENGARUH METODE PEMISAHAN PELARUT DALAM GEL TERHADAP SIFAT FISIK TITANIA-ALUMINA SEBAGAI PENYANGGA KATALIS Silvester Tursiloadi; Dewi Sondari; Nino Renaldi; Hiroshi Hirashima
Jurnal Sains Materi Indonesia Vol 4, No 2: FEBRUARI 2003
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2003.4.2.4882

PENGARUH METODE PEMISAHAN PELARUT DALAM GEL TERHADAP SIFAT FISIK TITANIA-ALUMINA SEBAGAI PENYANGGA KATALIS. TiO2-Al2O3 gel monolitik dalam nisbah mol 0,2 untuk TiO2 dan 0,8 untuk Al2O3 telah dibuat dengan cara hidrolisis dari aluminium sec-butoksida, Al (OC4H9sec)3 dan titanium isopropoksida Ti(OC3H7iso)4 dalam larutan n-propanol dengan katalis asam. Pemisahan pelarut dalam gel dilakukan dengan dua cara, pertama pengeringan pada tekanan atmosfer hingga terbentuk xerogel. Kedua, pemisahan pelarut pada kondisi CO2 superkritik, hingga terbentuk aerogel. Terbentuknya gugus Ti-O, salah satu dari titanium dioksida atau jaringan polimer –Ti-O-Ti-O-Al-O- ditunjukkan dengan adanya puncak antara 500 dan 900 cm-1 yang tajam tetapi lebar pada spektrum infra merah. Puncak yang kuat pada 1635 cm-1 menandakan adanya gugus –OH uluran yang merupakan derajat yang tinggi dari permukaan hidroksilasi. Volume kumulatif pori-pori dari xerogel sangat kecil jika dibandingkan dengan aerogel hasil pemisahan pelarut pada kondisi CO2 superkritik. Fase anatase TiO2 tidak terbentuk selama proses kristalisasi hingga kalsinasi sampai suhu 1000oC. Pengkristalan alumina terjadi secara langsung dari fasa amorf Al2O3 ke fasa α-Al2O3 dan fasa-fasa antara θ- dan γ-Al2O3 tidak teramati. Dari hasil tersebut dapat diperkirakan bahwa selama kalsinasi partikel TiO2 terpisah dari partikel Al2O3 membentuk inti atom rutil sebelum terbentuknya kristal α-Al2O3. Karena itu pembentukan fasa rutile TiO2 akan mempercepat terbentuknya fasa α-Al2O3. Keasaman campuran titania alumina setelah dikalsinasi pada suhu 500 oC lebih tinggi daripada oksidanya masing-masing, yaitu TiO2 dan Al2O3. Hal ini disebabkan oleh terbentuknya asam Lewis dari campuran titania-alumina.

A Review on the Hydroisomerisasion of n-Parafins over Supported Metal Catalysts Muhammad Safaat; Indri Badria Adilina; Silvester Tursiloadi
Jurnal Rekayasa Proses Vol 15, No 2 (2021)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.67587

Catalytic hydroisomerization of n-paraffin aims to produce branched paraffin isomers and suppress cracking reactions in the production of the low cloud point of biodiesel. The development of the type of metal and catalyst support, amount of metal loading, and reaction conditions are important to increase the catalyst activity. A high performace catalyst for hydroisomerization bears bifunctional characteristics with a high level of hydrogenation active sites and low acidity, maximizing the progress of hydroisomerization compared to the competitive cracking reaction. In addition, a catalyst support with smaller pore size can hinder large molecular structure isoparaffins to react on the acid site in the pore thus providing good selectivity for converting n-paraffin. Catalysts loaded with noble metals (Pt or Pd) showed significantly higher selectivity for hydroisomerization than non-noble transition metals such as Ni, Co, Mo and W. The reaction temperature and contact time are also important parameters in hydroisomerization of long chain paraffin, because long contact times and high temperatures tend to produce undesired byproducts of cracking. This review reports several examples of supported metal catalyst used in the hydroisomerization of long chain hydrocarbon n-paraffins under optimized reaction conditions, providing the best isomerization selectivity results with the lowest amount of byproducts. The role of various metals and their supports will be explained mainly for bifunctional catalysts.

A Review on the Hydroisomerisasion of n-Parafins over Supported Metal Catalysts Muhammad Safaat; Indri Badria Adilina; Silvester Tursiloadi
Jurnal Rekayasa Proses Vol 15, No 2 (2021)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.67587

Catalytic hydroisomerization of n-paraffin aims to produce branched paraffin isomers and suppress cracking reactions in the production of the low cloud point of biodiesel. The development of the type of metal and catalyst support, amount of metal loading, and reaction conditions are important to increase the catalyst activity. A high performace catalyst for hydroisomerization bears bifunctional characteristics with a high level of hydrogenation active sites and low acidity, maximizing the progress of hydroisomerization compared to the competitive cracking reaction. In addition, a catalyst support with smaller pore size can hinder large molecular structure isoparaffins to react on the acid site in the pore thus providing good selectivity for converting n-paraffin. Catalysts loaded with noble metals (Pt or Pd) showed significantly higher selectivity for hydroisomerization than non-noble transition metals such as Ni, Co, Mo and W. The reaction temperature and contact time are also important parameters in hydroisomerization of long chain paraffin, because long contact times and high temperatures tend to produce undesired byproducts of cracking. This review reports several examples of supported metal catalyst used in the hydroisomerization of long chain hydrocarbon n-paraffins under optimized reaction conditions, providing the best isomerization selectivity results with the lowest amount of byproducts. The role of various metals and their supports will be explained mainly for bifunctional catalysts.

PREPARATION OF LEAD ZIRCONATE TITANATE FILM BY SOL-GEL METHOD AND ITS CHARACTERIZATION Silvester Tursiloadi; Hiroaki Imai; Hiroshi Hirashima
Jurnal Kimia Terapan Indonesia Vol 6, No 1-2 (1996)
Publisher : Research Center for Chemistry - LIPI

A ferroelectric material film of Lead Zirconate Titanate, Pb(Zr,Ti)O3 (PZT), was produced by sol-gel method from alkoxide and acetate precursors in a normal propanol solvent system. The excess amount of Pb was 10 mole % more than stoichiometrically used for preparing the solution. The concentration of PZT in coating solution was 0.7 M, and pH of the solution was 4.5. The films was prepared by dip-coating onto slide glass, silica glass and Pt/Ti/SiO2/Si substrate. In order to avoid cracking TiO2 was coated on the glasses as a barrier layer. The asdried PZT film was amorphous from X-ray diffraction. The amount of pyrochlore and perovskite phase depended on the heating temperature and kind of barrier layer. Single perovskite phase was found for coated films on TiO2/SiO2 and Pt/Ti/SiO2/Si heated at 600° C or higher, but it was never found for coated films on SiO2 substrate without barrier layers. Crystallization of perovskite PZT film was retarded when deposited on amorphous substrates as compared to crystalline substrate. The coated film on Pt/Til/SiO2/Si was thicker and smaller in particle size than that of coated film on Ti02/SiO2. A columnar structure with a diameter around 6.5 nm, was observed and no boundary was observed between layers in 9 time dipcoated film on Pt/Ti/SiO2/Si.

Carbonization of Palm Oil Empty Fruit Bunch (EFB) in Hydrothermal Processes to Produce Biochar Rakhman Sarwono; Silvester Tursiloadi; Kiky Corneliasari Sembiring
Jurnal Kimia Terapan Indonesia Vol 18, No 02 (2016)
Publisher : Research Center for Chemistry - LIPI

ABSTRACT Empty fruit bunch (EFB) of palm oil is a waste from the palm oil industries which in a large amount, those waste is not properly utilized yet. EFB is a lignocelluloses waste as a polymer with big molecule such as cellulose, lignin, and hemicelluloses that can be degraded into smaller molecules in hydrothermal carbonization (HTC) process. The HTC process of EFB will result three fractions such as gas, organic water soluble and biochar as solid residue or bio-char-water-slurry. EFB degradation is influenced by the operation conditions such as temperature, pressure, catalysts, reaction time, stirring and ratio liquid and solid. The HTC process involved many routes of reaction such as liquefaction, hydrolysis, dehydration, decarboxylation, condensation, aromatization, and polymerization. In this experiment 60 ml closed vessel was used as the HTC reactor to degrade of EFB. EFB concentration of 6.44% resulted 62% of conversion. Reaction time of 6 hours resulted 62 % of conversion. Increasing the reaction time and temperature increase the conversion of EFB. Liquid products of organic water soluble has cleared yellow color, after several hours the color become darkness that is further reaction still occurs in that solution. Solid products is biochar as brown coal, that can be easily separated and processed into powder, pellet or briquette form with outstanding storage and transport characteristics. For further economic development, biochar with excellent transport characteristics, the possibility of exporting this commodity to the world’s energy market is possible. Key words: EFB, hydrothermal, carbonization, conversion, biochar

Proses Dekomposisi untuk Pembuatan Serbuk Alumina dari Aluminium Format Silvester Tursiloadi
Jurnal Kimia Terapan Indonesia Vol 9, No 1-2 (1999)
Publisher : Research Center for Chemistry - LIPI

The high purity excellent chemical stability and mechanical properties, is quite important for alumina ceramic products. The alumina ceramic products was made from aluminium formate in this study. Decomposition of organic salts is a useful method for preparation of pure and fine ceramic powder without using of expensive metal alkoxides and without producing air pollution. The aluminium formate alt was prepared from reagent grade AlCl3.6H2O,AlCl3.6H2O was dissolved in H2O and then NH4OH was added to the solution. The white precipitates formed were washed with distilled water repeatedly, then dissolved in formic acid solution. Alumina powders prepared by decomposition of aluminium formate had high chemical purity and had small size of agglomerates with a narrow size distribution. The spesific surface area and the equivalent spherical diameter calculated from the value of spesific surface area were 60 m2/gr and 0.03um. The value of equivalent spherical diameter of Al2O3 powder in cumulative mass percent for finer particle were diameter (10%) of 1.7um and diameter (50%) of 5,5um. The average diameter of particles was 5.5um. For the alumina powders which was prepared by docomposition of aluminium formate, the x- Al2O3 and x- Al2O3 did not appear as intermediate phase between y- Al2O3 and a- Al2O3 when calcinated from 800°C to 900°C .However a- Al2O3 phase appeared at 800°C, so that this could reduce the transition temperature from y- Al2O3 to a- Al2O3. The single phase of a- Al2O3 was obtained after calcinating at 1100°C or more for 2 hours.

CHEMICAL CATALYTIC AND BIOCATALYTIC PROCESS OF CLOVE OIL DERIVATIVES REVIEW Silvester Tursiloadi; Nina Artanti; Anny Sulaswatty
Jurnal Kimia Terapan Indonesia Vol 17, No 1 (2015)
Publisher : Research Center for Chemistry - LIPI

In 2011, Indonesian clove oil supply reached about 75 % (4,500 of 6,000 tons) of the world market. Utilization of clove oil and clove oil derivatives in aromatic chemical industry primarily as a mixture or additive of fragrances in the daily consumed product, such as perfumes, skin care products, deodorant, soap, shampoo, detergent, besides it is also used as an ingredient in the production of synthetic vanilla.Â The content of eugenol as the main compound in the essential oil in the clove flower, flower stalk and leaf have a range of 90-95 %, 83-95 % and 82-87 % respectively.Â The compounds content in clove oil is divided into two categories, phenolics (eugenol) and non-phenolic (beta-caryophyllene) that can be derivatized with various chemocatalytic and biocatalytic processes. Separation of the compounds in clove oil can be conducted by adding NaOH with repeated distillation. This process produces two layers product, the first layer contains eugenol and NaOH, while the second layer contains beta-caryophyllene. Derivatization of eugenol are conducted to produce various products such as vanilla, eugenyl ether, methyl ether eugenyl, eugenyl ethyl ether, eugenyl acetate, eugenyl cinnamate, dimmer eugenol and eugenyl benzoate, whereas derivatization of beta-caryophyllene are conducted to produce products such as caryophyllene oxide, kobusan, glycols, alcohols caryophyllene, Î²-caryolanylformate and kovanilformate, klovanildiformate, caryophyllene ketol.Â Biocatalysis or biotransformation can be defined as the use of biological systems (intact cells, cell extracts or isolated enzymes) to catalyze the conversion of a compound into another. Besides the common chemocatalysis system for derivatization of clove oil and clove oil compound such as eugenol into other compounds some biocatalysis systems were also described in this paper.Keywords: Clove oil, eugenol, beta-caryophyllene, derivatization, chemical catalysis, biocatalysis

PEMBUATAN KERAMIK KORDIERIT DENGAN METODE SOL-GEL DAN KARAKTERISASI-NYA Silvester Tursiloadi
Jurnal Kimia Terapan Indonesia Vol 10, No 1-2 (2000)
Publisher : Research Center for Chemistry - LIPI

Sol-gel method and melt-quenching as a reference methodwere studied for preparing a-cordierite phase. The solution ofcordierite precursor was prepared from a mixture of Si(O-Et),Al(O-Bu'), and Mg (O-EI)2 in 2-methoxyelhanol. The alkoxidesolution thus obtained was hydrolyzed with NH4OH-water. Thegel obtained was aged 80'C. After aging for more than one day,the products were dried at 120'C for 24 hours in dry oven. Allthe gel powders obtained were heat-treated up to 1050°C. Theirphase transformation was studied by using a DTA and X-raydiffraction. It was found that different crystallization behaviorswere shown by the Al/Si ratio in gel powders. As the amount of.41 atoms decreased the exothermic peak of DTA due tocrystallization shifted to lower temperature and the initialtram/ormation of a-cordierite phase front u-cordierite took placeby heat-treating at 900'C for 1 hour. However, the completetram/ormation of single a-cordierite phase took place at highertemperature than Al-rich samples. Although the calcination wasdone at 1050·C for 1 hr, the phase of u-cor dierite was stillobserved. Transformation of u-cordierite to a-cordierite phasefor Al-rich samples showed al a higher temperature comparedfor Al-poor samples, although the complete transformation tookplace at a relatively low temperature, compared with solid statereaction.The increase in Al concentration will increase the density ofsamples. The density of all samples were increased up to thecalcination temperature of 950·C, and the highest density wasobtained at 1050·C. The sample which was prepared by 'meltquenching'method, showed that the density of the sample was almostthe same although the calcination temperature was increased up tomore than 900'C. After calcination at 1050'C, the Al-rich samplehas a density of around 3,32 g/cm3 (93% of density standardcordierite).

Pembuatan dan Karakteristik Serbuk Piezoelektrik Pb(Zr,Ti)03 tanpa subtitusi dan dengan Nb substitusi Silvester Tursiloadi
Jurnal Kimia Terapan Indonesia Vol 8, No 1-2 (1998)
Publisher : Research Center for Chemistry - LIPI

The characteristics of chemically prepared piezoelectric PZT and doped PZT with niobium (PNZT) were investigated. PZT 55/45, both unmodified and doped with Nb2O5 were prepared by the hydrolysis of metal alkoxides and solid state reaction from PbO, ZrO, and TiO,. The average particle size was 0.45 um. X-ray diffraction results indicated that transformation of the amorphous precipitate be came well crystallized PZT after heating at 500 °C for 6 hours. DTA results suggested theformation of an intermediate PbTiO3 phase at 490 °C. Using X-ray diffractton can be investigated occurring of both tetragonal and rombohedral ferroelectric PZT phases. That case depends on the initial mixing of chemical composition. The PZT powders which prepared from alkoxides were agglomerated easly at low temperature calcining. Poor sintered bodies will he resulted it was calcinated above 600°C. Powders calcined at 500 °C for 6 hours and sintered at 1200 °C produced high body densities approaching 95% of theoretical density.The experimental results suggest that intimate mixing of constit uents during the hdrolyt ic decomposition produces a homogeneous powder. However, differences in the rate hydrolysis or polymerization of the respective metal alkoxides fend to couse the stoichiometric results difficult to be found.

LOW-TEMPERATURE SYNTHESIS OF LEAD ZIRCONATE TITANATE (PZT) POWDER FROM METAL ALKOXIDES Silvester Tursiloadi; Hiroaki Imai; Hiroshi Hirashima
Jurnal Kimia Terapan Indonesia Vol 5, No 1 (1995)
Publisher : Research Center for Chemistry - LIPI

PZT powder precipitate has been prepared by hydrolyzing a mixture of lead di-i-propoxide, zirconium tetra-n-butoxide and titanium tetrai-propoxide. The crystallization process of the amorphous PZT was studied by means of X-ray diffraction analysis. It was found that the powder precipitate was still amorphous on heating until 400°C for 2k As an intermediate product, metastable cubic Pb2Ti2O6 (pyrochlore phase) was found after heating at 450°C for 2h. In addition to Pb2Ti206 peaks, the diffraction peaks of perovskite PZT phase were observed after heating at 430°C for 24 h. After heating at 600 °C for 2h, only diffraction peaks of tetragonal perovskite PZT phase were found. The lattice parameters of the tetragonal PZT have been obtained to be a=4.066 A c=4.196 A This tetragonal perovskite phase was stable on heating until 1000 "C. The density of the compacted powder precipitate after heating at 1000°C (a relatively low temperature for the sintering of PZT) for 30 min. was 6.1 g/cm3, about 76% of the theoretical value.

Title

Found 11 Documents
Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title Search

Found 11 Documents Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title

Found 11 Documents
Search