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Indonesian Journal of Chemistry

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Published by Universitas Gadjah Mada

ISSN : 14119420 EISSN : 24601578 DOI : -

Core Subject : Science, Engineering,

Chemical Engineering, Chemistry & Bioengineering Chemistry

Indonesian Journal of Chemistry is an International, peer-reviewed, open access journal that publishes original research articles, review articles, as well as short communication in all areas of chemistry including applied chemistry. The journal is accredited by The Ministry of Research, Technology and Higher Education (RISTEKDIKTI) No : 21/E/KPT/2018 (in First Rank) and indexed in Scopus since 2012. Since 2018 (Volume 18), Indonesian Journal of Chemistry publish four issues (numbers) annually (February, May, August and November).

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Articles 23 Documents

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Search results for , issue "Vol 8, No 1 (2008)" : 23 Documents clear

EFFECT OF CERIUM ON HYDRODESULFURIZATION CATALYST PERFORMANCE Triyono Triyono; Wega Trisunaryanti
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Effect of cerium on hydrodesulfurization catalysts performance have been investigated. The catalysts were Pt or Pt-Ce supported on zeolite. The Pt/Zeolite catalyst was prepared by wet impregnation method, while that of Pt-Ce/Zeolite catalyst was prepared using coimpregnation method both were followed by drying, calcination, oxidation and reduction. The catalysts activity test was performed in a micro reactor and products composition was determined using gas chromatography. The results showed that cerium enhanced catalyst performance especially catalyst lifetime. Therefore, the catalysts have higher tendency to remain active for longer period. Due to its function, cerium might be used as a promoter of hydrodesulfurization catalysts.

FTIR AND NMR STUDIES OF ADSORBED CETHYLTRIMETHYLAMMONIUM CHLORIDE IN MCM-41 MATERIALS Paulina Taba; Russell F. Howe; Graine Moran
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The high use of surface-active agents (surfactants) by industry and households today leads to environmental pollution, therefore treatments are required to remove such substances from the environment. One of the important and widely used methods for removal of substances from solution is adsorption. In this research, MCM-41 and its modified product of MCM41-TMCS were used to adsorb cationic surfactants, cethyltrimethylammonium chloride, CTAC. FTIR and NMR methods were used to study the interaction between the surfactants and the adsorbents. MCM-41 was synthesized hydrothermally at 100 oC and its modification was conducted by silylation of MCM-41 with trimethylchloro silane (MCM41-TMCS). Both unmodified and modified MCM-41 can adsorb the surfactant. The interaction of CTAC with MCM-41 was mostly the electrostatic interaction between the electropositive end of the surfactant and MCM-41, whereas in modified MCM-41 hydrophobic interactions become more dominant. These hydrophobic interactions appear however to involve the methyl groups on the head group of the surfactant interacting with the modified surface.

FOUR-FACTOR RESPONSE SURFACE OPTIMIZATION OF THE ENZYMATIC SYNTHESIS OF WAX ESTER FROM PALM KERNEL OIL Erin Ryantin Gunawan; Dedy Suhendra
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The synthesis of wax ester using refined, bleached and deodorized (RBD) palm kernel oil (PKO) and oley alcohol catalyzed by Lipozyme IM was carried out. Response surface methodology (RSM) based on a five-level, four-factor central composite rotatable design (CCRD) was used to evaluate the interactive effects of synthesis, of reaction time (5-20 h), temperature (20-50 oC), amount of enzyme (0.1-0.2 g) and substrate molar ratio (palm kernel oil to oleyl alcohol, 1:1-1:5) on the percentage yield of wax esters. The optimum condition conditions derived via RSM were reaction time 8.46 h, temperature 44.4 oC, amount of enzyme 0.182 g, substrate molar ratio 1 to 3.7. The actual experimental yield was 92.9 % under optimum condition, which good accordance to the maximum predicted value of 92.4 %.

INTERCALATION OF OLYGOMER OF HYDROXYL-CHROMIUM INTO NATURAL KAOLINITE Rodiansono Rodiansono; Reda Ariyantie; Abdullah Abdullah
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Preparation of a kaolin-hydroxyl chromium composite and characterization of its physico-chemical properties were conducted. The olygomer hydroxyl-chromium was prepared by adding Na2CO3 to 0.1 M chromium nitrate solution (ratio OH/Cr = 2) and then dried at 110 oC and 400 oC for 4 h. Characterization of kaolin-hydroxyl chromium composite includes determination of acidity, functional groups, basal spacing, and surface area (BET-N2 sorption analyzer). The result showed that intercalation of hydroxyl chromium resulted in the decreasing of basal spacing but increased the specific surface area of kaolin. Drying of the intercalated kaolin at 400 oC decreased surface area, total volume pore and pore radius. FT-IR spectra showed that hydroxyl-chromium detected at wavelength of 2925 and 2855 cm-1.

OXIDATION OF BENZYLIC SECONDARY ALCOHOL WITH PYRIDINIUM CHLOROCHROMATE-ALUMINA (PCC-Al2O3) Hanoch J. Sohilait
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

In these studies, Pyridinium chlorochromate-Alumina was used for oxidation of secondary alcohols (safryl alcohol and methyleugenyl alcohol) to ketone. The oxidation of safryl alcohol with PCC-Al2O3 followed by purification by potassium bisulfite yields safryl ketone (62,92%). The oxidation of methyleugenyl alcohol with PCC-Al2O3, followed by purification by potassium bisulfite yields methyleugenyl ketone (68,04%). The elucidation of these products was analyzed by FTIR, 1H-NMR and MS.

THEORETICAL STUDY OF SOLVENT EFFECTS AND NMR SHIELDING TENSORS OF DLPC M. Monajjemi; S. Afsharnezhad; M.R. Jaafari; S. Mirdamadi; H. Monajemi; S. Mollaamin
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The effect of the polarity of the environment on the conformation zwitterionic membrane dilauroyl phosphatidylcholine (DLPC) has been investigated with calculation at the Hatree-Fock level using the 6-31G* basis set with Onsager continuum solvation model. The ‘Gauge Including Atomic Orbital' (GIAO) approach is used to investigate Ab initio GIAO calculations of NMR chemical shielding tensors carried out within SCF-Hartree-Fock approximation are described. In order to compare the calculated chemical shifts with experimental ones, it is important to use consistent nuclear shielding for NMR reference compounds like TMS. Conformation of DLPC was evaluated with four different solvents with different dielectric constant (Water (ε = 78.39), Dimethyl Sulfoxide (ε = 46.7), Acetone (ε = 20.7) and Heptane (ε = 1.92). In concern with conformational energy, Water could be the most suitable solvent for DLPC. Moreover, as the polarity of the medium increase, the conformational stability of this molecule increases faster than that of DLPC in the gas phase. Consequently, the relative energy of DLPC also depends on the polarity of the environment. This subject was considered as well as the most variable in some dihedral angles degree and NMR isotropic shift were in the less dielectric constant (ε = 1.92). It could be in polar medium DLPC conformer becomes additionally stabilized by intermolecular ionic and hydrogen bond interactions with polar neighboring molecules. On the basis of this work it can be concluded that the effect of the polarity of the environment clearly are influenced on the isotropic values by geometry variation due to intermolecular motion in molecule.

RbNb6Cl12O2: CRYSTAL STRUCTURE AND MAGNETIC PROPERTIES Fakhili Gulo
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

A novel niobium oxychloride cluster compound, RbNb6Cl12O2 was obtained by solid state synthesis from stoichiometric mixture of RbCl, Nb2O5, NbCl5 and Nb powder, heated at 675 °C. Its structure was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic system (a = 6.8097(4) Å, b = 11.6700(9) Å, c = 12.5090(9) Å, ß = 101.337(4) °, V = 974.68(12) Å3, and Z = 2) with the space group of P21/c. The cluster framework of this compound is based on units connected via oxide ligands in the a-direction with two Nb-O linkages between adjacent clusters, which resembles intercluster bonding in Chevrel-Sergent phases. In the other two directions, the linkages occur through single Cla-a bridges. The framework generates channels where the cations Rb+ are located. This compound contains valence electron concentration (VEC) of 15 per cluster unit and therefore exhibits the paramagnetic behavior.

SOLVATOCHROMIC AND SUBSTITUENT EFFECT ON ELECTRONIC ABSORPTION OF ARENETRICARBONYLCHROMIUM(0) COMPLEXES Agus Abhi Purwoko
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

A number of arenetricarbonylchromium(0) complexes, [(η6-arene)Cr(CO)3], in which arene = benzene, chlorobenzene, phenyltrimethylsilane, and acenaphthene were synthesized. Electronic absorptions of these complexes were recorded in various solvents, ranging from polar to non polar ones; i.e. methanol, methylene chloride, chloroform, benzene, and isooctane. These chromium tricarbonyl complexes show lowest electronic absorption in the energy range of 313 - 320 nm, with relatively high intensity (ε = 0,9 - 2,0 x 104 M-1cm-1). Detailed discussion of the solvent and substituent effect on electronic absorption of these complexes are presented in this article.

PHOTO-REDUCTION KINETICS OF MnO2 IN AQUATIC ENVIRONMENTS CONTAINING HUMIC ACIDS Narsito Narsito; Sri Juari Santosa; Setya Lastuti
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The kinetics of photo-reduction of manganese(IV) oxide, MnO2 in aqueous medium, in the presence of humic acid has been investigated, including the possibility for the involvement of such radicals in the reduction. Results showed that in aqueous medium, the efficiency of the photo-reduction of MnO2 producing a soluble ionic Mn(II) was governed strongly by an internal electron transfer within an intermediate of HA-MnO2 anion complex, resulted in the chemical adsorption of humic acid on MnO2 surface. It was observed that under solar radiation and atmosphere containing oxygen, the rate of MnO2 reduction increased considerably, by factors of about 46 and 2 respectively. Moreover, there was evidence that some radicals certainly played a role in the photo-reduction of MnO2, since radical scavenger addition significantly decreased the reduction efficiency of MnO2. In the present of an excess of propanol-2, however, which was expected to remove all OH radicals present, only about 60 % decrease in reduction efficiency were observed, suggesting that radicals other than OH radical are involved in the reduction of MnO2. It was observed further that the presence of iron(III) in MnO2 up to 1 % (w/w) did not alter the reduction efficiency of MnO2.

WHIM-3D-QSPR APPROACH FOR PREDICTING AQUEOUS SOLUBILITY OF CHLORINATED HYDROCARBONS Oman Zuas
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

The weighted holistic invariant molecular-three dimensional-quantitative structure property relationship (WHIM-3D-QSPR) approach has been applied to the study of the aqueous solubility (- log Sw) of chlorinated hydrocarbon compounds (CHC's). The obtained QSPR model is predictive and only requires four WHIM-3D descriptors in the calculation. The correlation equation of the model that is based on a training set of 50 CHC's compound has statistical parameters: standard coefficient correlation (R2) = 0.948; cross-validated correlation coefficients (Q2) = 0.935; Standard Error of Validation (SEV) = 0.35; and average absolute error (AAE) = 0.31. The application of the best model to a testing set of 50 CHC's demonstrates a reliable result with good predictability. Besides, it was possible to construct new model by applying WHIM-3D-QSPR approach without require any experimental physicochemical properties in the calculation of aqueous solubility.

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