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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 1,981 Documents

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SYNTHESIS OF IRON OXIDE-MONTMORILLONITE COMPOSITE AND STUDY OF ITS STRUCTURAL STABILITY AGAINTS SULFURIC ACID Karna Wijaya; Eko Sugiharto; Mudasir Mudasir; Iqmal Tahir; Ika Liawati
Indonesian Journal of Chemistry Vol 4, No 1 (2004)
Publisher : Universitas Gadjah Mada

The synthesis and characterization of iron oxide-montmorillonite and its structural stability test with various concentration of sulfuric acid were conducted. Synthesis was performed by treating Na-montmorillonite clay with oligocations of iron, followed by calcinating the intercalation compound of oligocations-montmorillonite at 200oC for 24 hours. Calcined product was then characterized to determine the iron content, basal spacing and its porosities distribution. To test structural stability againts strong acid (i.e. sulfuric acid), the composites were dispersed into solution of sulfuric acid with various concentration, i.e: 1, 2 and 3M for 24 hours.The characterization result, especially from x-ray-diffractometry analysis, demonstrated that modification of montmorillonite using iron (III)oxide produced so called house of card structure as indicated by its broad, low intensity reflection at 2θ = 5-6o. The addition of sulphuric acid into composite resulted in probably the formation of face to face arrangements indicated by the appearance of 001 plane reflection. The acid treatment also caused the decrease in the iron content of the iron oxide-montmorillonite as shown by its neutron activated analysis result. The iron content of iron oxide-montmorillonite before the acid treatment was 32,01% w/w, and after the acid treatment was 14.08% w/w (with sulfuric acid of 1M), 6.05% w/w (sulfuric acid of 2M) and 5,98% w/w (with sulfuric acid of 3M), respectively.In general, the sulphuric acid treatment to the composite did not distore the 001 planes of the montmorillonite.

STRUCTURE ELUCIDATION OF ANTIBACTERIAL COMPOUND FROM Ficus deltoidea Jack LEAVES Suryati Suryati; Hazli Nurdin; Dachriyanus Dachriyanus; Md Nordin Hj Lajis
Indonesian Journal of Chemistry Vol 11, No 1 (2011)
Publisher : Universitas Gadjah Mada

An antibacterial compound has been isolated from Ficus deltoidea Jack leaves. Based on spectroscopic data (IR, 1H-NMR, 13C NMR 1D and 2D and MS), the structure of this compound was identified as 3β-hydroksilup-20(29)-en, (lupeol), C30H50O. This compound showed antibacterial activities against E. coli, B. subtilis and S. aureus. The minimum inhibition concentration (MIC) against E. coli, B. subtilis and S. aureus are 150, 220 and 130 μg/mL respectively.

CHARACTERIZATION OF IMMOBILIZED LIPASE IN ALUMINOSILICATE FOR LACTOSYL PALMITATE SYNTHESIS Anna Roosdiana; Tutik Setianingsih; Diah Mardiana; Suratmo Suratmo
Indonesian Journal of Chemistry Vol 9, No 2 (2009)
Publisher : Universitas Gadjah Mada

Whey lactose can be esterified enzymatically by using immobilized lipase. The lipase can be isolated from Rhizopus oryzae, purified and immobilized in mesoporous aluminosilica. The use of immobilized lipase has advantages, there are longer shelf life and repeatable use. It is necessary to characterize the immobilized lipase dan ester product. The aim of the research was to characterize immobilized lipase, including determination lipase adsorption type in mesoporous aluminosilicate, immobilized lipase stability during storage time, efficiency of repetitive use of immobilized lipase. The result showed that lipase adsorption in mesoporous aluminosilicate was physical adsorption type through hydrogen bound and electrostatic interaction. Immobilized lipase stability was relatively constant at storage temperature 5 °C for 25 days resulting in 98.16% of initial activity. The repetitive use of immobilized lipase showed efficient until 5 uses within activity of 50.22%. The IR spectra of lactosyl palmitate from both whey and pure lactose result showed bands at wavelength number of 3462 cm-1(OH bond), 1739 cm-1 and 1747 (C=O ester bond) 1295 cm-1 dan 1242 cm-1 (C-O ester bond). In addition, the HLB value for lactosyl palmitate (whey) 4.708 and lactosyl palmitate (pure lactose) 4.715, therefore both lactosyl palmitate is appropriate as emulgator in W/O.

QUANTITATIVE RELATIONSHIPS BETWEEN MOLECULAR STRUCTURE AND MELTING POINT OF SEVERAL ORGANIC COMPOUNDS Iqmal Tahir; Karna Wijaya; M Utoro Yahya; Muzakky Yapin
Indonesian Journal of Chemistry Vol 2, No 2 (2002)
Publisher : Universitas Gadjah Mada

Quantitative Structure - Property Relationships (QSPR) analysis of the Melting Point (m.p) of 349 organic compounds using molecular descriptors based on linear regression have been done. The experiment m.p. values were collected from the CRC Hand Book of Chemistry and Physic 81th [1]. Molecular description of each compound was described in the form of the number of atoms and number of chemical bonding. This study was made in the form of normal melting point (in Kelvin unit) as the linear function of all molecular descriptor. The best equation model was determined by regression multilinear analysis and the result showed that the melting point is linearly correlated with: n(Csek alf), n(Cter alf), n(Csek sik), n(Cter sik), n(Csek arm), n(Cter arm), n(O), n(N), n(F), n(Cl), n(C-C sik), n(C=C arm), n(C1=C2), n(C2=C3), n(C-O), n(C-Br), n(C-I), n(N-H), n(Z), n(ortho), n(meta), n(para), (BM), n(C-H)2, n(H x BM) and n(Cprim x BM). The QSPR equation is significant at 95 % level and has statistical parameters: n = 349, r = 0.943, SD = 24.336 and Fexp = 99.326, respectively.

SOL-GEL DERIVED Co AND Ni BASED CATALYSTS: APPLICATION FOR STEAM REFORMING OF ETHANOL Haryo Satriya Oktaviano; Wega Trisunaryanti
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Cobalt and nickel based catalysts for ethanol steam reforming have been prepared. Preparation of Na-Ni-Mo/C, Na-Co-Mo/C, K-Ni-Mo/C and K-Co-Mo/C have been carried out using sol-gel method by applying citric acid as complexion agent and source for support formation. Prepared catalyst via sol gel showed tailored morphological properties signed by tailored pore size distribution. The acidity of catalyst showed that all catalysts contain only Lewis acid site. The catalyst activity test was conducted by using semi flow method with molar ratio of ethanol : water = 0.33 at 400 oC

THE EFFECTS OF BORON ADDITION AND PRESULFIDATION TEMPERATURE ON THE HDS ACTIVITY OF A Co-MoS2/Al2O3 CATALYST Usman Usman; Takeshi Kubota; Yasuaki Okamoto
Indonesian Journal of Chemistry Vol 5, No 2 (2005)
Publisher : Universitas Gadjah Mada

The effect of boron addition was studied on the hydrodesulfurization (HDS) of thiophene over Co-MoS2/B/Al2O3 (CVD-Co/MoS2/B/Al2O3), which was prepared by a CVD technique using Co(CO)3NO as a precursor of Co. The catalyst was characterized by means of NO adsorption, XPS, Raman Spectroscopy, FTIR, and TEM. The HDS activity of CVD-Co/MoS2/B/Al2O3 catalyst increased as the boron content increased up to about 0.6 and 1.2 wt% B for the catalyst presulfided at 673 and 773 K respectively, followed by a decrease with a further addition of boron loading. In spite of the activity increase, the amount of NO adsorption on MoS2/B/Al2O3 steadily decreased with increasing boron loading, suggesting that the dispersion of MoS2 particles is decreased by the addition of boron. Selective formation of the CoMoS phase on CVD-Co/MoS2/B/Al2O3 was achieved by the CVD technique. The TOF of the HDS over the CVD-Co/MoS2/B/Al2O3 catalyst, defined by the activity per Co atom forming the CoMoS phase, increased as high as 1.6 and 1.9 times for the catalyst presulfided at 673 and 773 K, respectively. It is concluded that the addition of boron weakens the interaction between Mo oxides and Al2O3 surface, promoting the formation of the so called Co-Mo-S ";;;pseudo";;; type II over CVD-Co/MoS2/B/Al2O3 presulfided at 673 K. The Co-Mo-S ";;;pseudo";;; type II is a metastable phase with the TOF value intermediate between Co-Mo-S type I and type II. With CVD-Co/MoS2/B/Al2O3 presulfided at 773 K, the addition of boron promotes the formation of ";;;real";;; Co-Mo-S type II, possibly by the formation of well-crystallized MoS2 structure.

QM AND AB INITIO INVESTIGATION ON THE HYDROGEN BONDING, NMR CHEMICAL SHIFTS AND SOLVENT EFFECTS ON THE DPPE M. Monajjemi; A. Nouri; H. Monajemi
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

The hydrogen bonding effects that were produced from interaction of membrane lipid dipalmitoylphosphatidyl-ethanolamine (DPPE) with 1-5 water molecules, has been theoretically investigated through the quantum mechanical calculations at the Hartree-Fock level of theory and the 3-21G, 6-31G and 6-31G* basis sets with the computational package of Gaussian 98. According to the obtained results of the structural optimization of the isolated DPPE in the gas phase, we can see the evidences of interactions in the head group of this macromolecule (from the molecular point of view we have a proton transfer from the ammonium group to the phosphate oxygen of zwitterionic form. As we know that the hydrogen bonding of DPPE with water molecules which have surrounded its head group plays an important role in the permeability of DPPE. So, in order to understand the microscopic physico-chemical nature of this subject we have analyzed bond and torsion angles of DPPE before and after added water molecules. In this paper we have theoretically studied the complexes DPPE with water molecules which have surrounded its head group. As mentioned before, this theoretically study has been done through Hartree-Fock level of theory by using simple basis sets. Theoretical data shows that the interaction of head group of DPPE with water molecules causes some changes in the geometry of DPPE which were explained by the contribution of zwitterionic form of DPPE macromolecule, and finally hydrated DPPE becomes stable complex. Comparison between theoretical and experimental geometry data of DPPE macromolecule shows that the calculation at the HF/3-21 level of theory produces results which they are in better agreement with the experimental data. Moreover the hydrogen bonding effects on the NMR shielding tensor of selected atoms in the hydrated complexes of DPPE were reported. The ";Gauge Including Atomic Orbitals"; (GIAO) approaches within the SCF-Hartree-Fock approximation have been used in order to investigate the influence of hydrogen bonding of DPPE-water complex on the shielding tensors. Finally, the solvent affects on the stability of DPPE macromolecule, dipole moment and atomic charge of some selected atoms of DPPE molecule was discussed using Onsager model and Merz-Singh-Kolman schema.

SYNTHESIS OF POLY(ACRYLAMIDE-CO-ACRYLIC ACID)-STARCH BASED SUPERABSORBENT HYDROGELS BY GAMMA RADIATION: STUDY ITS SWELLING BEHAVIOR Erizal Erizal
Indonesian Journal of Chemistry Vol 12, No 2 (2012)
Publisher : Universitas Gadjah Mada

Modification of poly (acrylamide-co-acrylic acid) superabsorbent hydrogels with varying starch concentration (1-3%) via simultaneous gamma radiation have been carried out. The structure and morphology of copolymers were characterization by Fourier transform infra red spectroscopy and scanning electron microscopy. The gel fraction, swelling kinetics and the equilibrium degree of swelling (EDS) of the hydrogels were studied. It was found that the an increase in the starch content present in the hydrogels (1-3%) and with increase irradiation dose from 10 kGy up to 30 kGy, the swelling ratio decreased from 250-100 g/g. Incorporation of 1% starch increases the EDS of the hydrogels up 350 g/g. Under maximum conditions, poly(AAm-co-AA)-starch hydrogels with high gel fraction (~93%) was prepared from aqueous solution containing 5% AAm, 15% acrylic acid and 0-3% starch. The hydrogels were sensitive against salts solution.

DETERMINATION OF MINERAL CONTAIN AND BACTERIA CONTAMINANT ON ORGANIC AND NONORGANIC FRESH VEGETABLES Harsojo Harsojo; June Mellawati
Indonesian Journal of Chemistry Vol 9, No 2 (2009)
Publisher : Universitas Gadjah Mada

The determination of mineral content and bacteria contaminant on fresh vegetable of long bean (Vegan ungulate Wall.), white cabbage (Basic tolerance L.), and lettuce (Lectuca sativa L.) that cultivated by organic and nonorganic system have been done. The mineral content has been analyzed using neutron activation analysis and atomic absorption spectroscopy method, while bacteria contaminant by total plate count number using Nutrient Agar, Mac Conkey Agar, Baird Parker medium, and Salmonella using selective medium. The results showed that there are some essential mineral such as Fe, Zn, Ca, Co, and nonessential mineral Cd. There is tendency that fresh vegetable that cultivated by organic system contained Fe, Zn, Ca, Co and Cd mineral less than nonorganic. The Zn mineral content in nonorganic of fresh vegetable were higher than the limit of threshold number from Health Department, Republic of Indonesia (2004), while Cd mineral in organic or nonorganic of fresh vegetable were greater then threshold number from Codex Alimentarius Commision. The measurement of bacteria contaminant on organic and nonorganic of fresh vegetables contained aerob, coli, and Staphylococcus bacteria in organic of fresh vegetables were less compared to nonorganic of fresh vegetables.

Effect of Residence Time of Graphitisation on Thermal Conductivity of Molded Graphite Pedy Artsanti; Yateman Arryanto; Kusnanto Kusnanto
Indonesian Journal of Chemistry Vol 1, No 1 (2001)
Publisher : Universitas Gadjah Mada

The effect of residence time of graphitisation on thermal conductivity of molded graphite has been examined. The examination has been conducted by varying residence time of graphitisation of molded carbon with petroleum coke as raw material and coal tar pitch. Graphitisation has been conducted by heating molded graphite at 2500 °C in argon atmosphere with residention time of 10, 30 and 90 minutes. Graphitisation degree, density, shrinking mass and porosity of molded graphite were examined and so was its thermal conductivity. The result showed that the decrease of porosity and the increase of graphitisation degree due to the increasing of residention time of graphitisation will increase the thermal conductivity of graphite. Molded graphite graphitisized with residence time for 90 minutes residention time gave thermal conductivity of 2.134 Watt/mK and graphitization degree 0.718.

Page 29 of 199 | Total Record : 1981

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