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Indonesian Journal of Chemistry

ijc
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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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BIOSORPTION OF Cr(III) ION ON ALGAE Eucheuma spinosum BIOMASSA I Wayan Sudiarta; Ni Putu Diantariani
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Studies on biosorption and desorption of Cr(III) on algae (Eucheuma spinosum) adsorbent have been carried out. These studies included determination of biosorbent acidity, optimum pH, contact time of biosorption, isoterm and biosorption capacity, and mechanisms of interaction between Cr(III) and algae (E. spinosum) biosorben. Mechanisms of interaction were evaluated by sequential desorption of Cr(III) on algae biosorben by using aquadest, 1 M HCl and 0.05 M Na2EDTA. The result showed that the total acidity of algae biosorbent was 4.15 ± 0.33 mmol/g, the optimum pH was 3, and the optimum contact time was 20 min. Biosorption capacity of algae (E. spinosum) toward chromium (III) was 57.33 mg/g. The highest desorption of Cr(III) achieved when 1 M HCl was used, i.e. 51,01%, wheareas desorptions using aquadest and 0.05 M Na2EDTA were relatively low, i.e. 2.07% and 2.38% respectively. This result indicates that the main interaction mechanism of Cr(III) on algae was electrostatic attraction.

PHASE TRANSFORMATION IN THE FORMATION OF FAUJASITE FROM FLY ASH Sutarno Sutarno; Yateman Arryanto
Indonesian Journal of Chemistry Vol 5, No 3 (2005)
Publisher : Universitas Gadjah Mada

Faujasite was hydrothermally synthesized from fly ash at 100oC in alkaline solution by reflux with 5M HCl and fusion with NaOH pretreatments. Phase transformation in the formation of faujasite was performed by variation of NaOH/fly ash weight ratios and hydrothermal times. The solid products were characterized by X-ray diffraction method. Results showed that faujasite was formed through dissolution of fly ash components such as quartz, mullite and amorphous aluminosilicates followed by crystallization to form faujasite. Arranging the NaOH/fly ash weight ratio as well as hydrothermal time can selectively form faujasite. Faujasite with crystallinity of 97.06%, Si/Al ratio of 2.68, and specific surface area of 452.93 m2/g was successfully formed using NaOH/fly ash weight ratio of 1.2 for hydrothermal time of 72 hours. In more concentrated alkaline solution as well as for longer hydrothermal time, faujasite was completely transformed into hydroxysodalite as the final product.

COMBINED BIOLOGICAL-PHOTOCATALYTIC TREATMENT FOR THE MINERALIZATION OF A MIXTURE OF CHLOROPHENOLS IN AN ELECTROLYTE-CONTAINING MODEL WATER AND SPONTANEOUS SEDIMENTATION OF TITANIUM DIOXIDE Dhanus Suryaman; Kiyoshi Hasegawa; Shigehiro Kagaya; Toshiaki Yoshimura
Indonesian Journal of Chemistry Vol 7, No 3 (2007)
Publisher : Universitas Gadjah Mada

To shorten the biological treating time and to examine the effect of electrolytes in a model water on the photocatalytic treatment, the combined biological-photocatalytic treatment was evaluated for removal of a mixture (total: 100 mg L-1, each: 25 mg L-1) of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,5-trichlorophenol (2,4,5-TCP), and pentachlorophenol (PCP) in tap water. The mineralization of the four phenols was performed by a flow (biological treatment)-circulative flow (photocatalytic treatment) operation under black light and sunlight irradiations. After a large portion of biodegradable 2-CP and 2,4-DCP, and around half amount of slightly biodegradable 2,4,5-TCP were removed by the biological treatment, the remained three chlorophenols, biorecalcitrant PCP, and biodegradation products were completely removed by the subsequent photocatalytic treatment. The combined treatment significantly shortened the degradation time only the biotreatment. High circulative flow rate (600 mL min-1) enabled for TiO2 particles to completely suspend in a tubular photoreactor and resulted in high removals of chlorophenols and TOC. Sunlight irradiation was successfully used and the saving of the electric energy of black light was possible. Since TiO2 particles in the tap water spontaneously sedimented on standing after the photocatalytic treatment, the combined system can be operated by integrating it with the TiO2 separation.

SECONDARY METABOLITE FROM ENDOPHYTIC FUNGI Aspergillus niger OF THE STEM BARK OF KANDIS GAJAH (Garcinia griffithii) Elfita Elfita; Muharni Muharni; Munawar Munawar; Septa Aryani
Indonesian Journal of Chemistry Vol 12, No 2 (2012)
Publisher : Universitas Gadjah Mada

Garcinia griffithii are known as kandis gajah including the Garcinia genus. This plant has been traditionally used by local communities Sarasah Bonta, Lembah Arau, West Sumatra, to treat various diseases including gout. Aspergillus niger was isolated from the tissues of the stem bark of Garcinia griffithii. The fungi strain was identified base on colony and cell morphology characteristic. Aspergillus niger cultured in media 5L Potatos Dextose Broth (PDB) for 8 weeks and filtered. Media that already contains secondary metabolites are partitioned using ethyl acetate solvent in 5 L (twice), followed by evaporation. Furthermore, the extract is separated by chromatographic techniques to obtain a pure compound of white crystal. The molecular structures of isolated compounds are determined by spectroscopic methods including IR, 1H-NMR, 13C-NMR, HMQC, HMBC, and COSY. The compound was determined as phenolic (1).

QSAR STUDY OF XANTHONE DERIVATIVES AS ANTI PLASMODIAL AGENTS Amanatie Amanatie; Jumina Jumina; Mustofa Mustofa; M. Hanafi; Ria Armunanto
Indonesian Journal of Chemistry Vol 10, No 3 (2010)
Publisher : Universitas Gadjah Mada

Xanthones and their derivatives have been reported to exhibit inhibitory activities towards Plasmodium falciparum. To provide deep insight into the correlation between inhibitory activities and structures of xanthones, linear regression method was employed to establish QSAR models for 16 xanthone derivatives that have diverse structures. The accuracy and predictive power of the proposed QSAR model were verified by semi empirical PM3 method, optimation, and validation. The result showed that the best model is model 3 i.e. Log 1/IC50 = Σ (-1.446)qO(7)+ (-8.775)q.C(12) + (-10.592)qC(13) + 1,979; Y = PRESS = 1.124192.

OPTIMIZATION OF TIME REACTION AND HYDROXIDE ION CONCENTRATION ON FLAVONOID SYNTHESIS FROM BENZALDEHYDE AND ITS DERIVATIVES Sri Handayani; Sunarto, Sunarto,; Susila Kristianingrum
Indonesian Journal of Chemistry Vol 5, No 2 (2005)
Publisher : Universitas Gadjah Mada

The aim of this research is to determine the optimum time of reaction and concentration of hydroxide ion on chalcone, 4-methoxychalcone and 3,4-dimethoxychalcone synthesis. Chalcone and its derivatives were synthesized by dissolving KOH in ethanol followed by dropwise addition of acetophenone and benzaldehyde. Then, the mixture was stirred for several hours. Three benzaldehydes has been used, i.e : benzaldehyde, p-anysaldehyde and veratraldehyde. The time of reaction was varied for, 12, 18, 24, 30 and 36 hours. Furthermore, on the optimum reaction time for each benzaldehyde the hydroxyl ion concentration was varied from 5,7,9,11 and 13%(w/v). The results of this research suggested that the optimum time of chalchone synthesis was 12 hours, while, 4-methoxychalcone and 3,4-dimethoxychalcone were 30 hours. The optimum concentration of hydroxide ion of chalcone synthesis was 13% and for 4-methoxychalcone and 3,4-dimethoxychalcone were 11%.

PRELIMINARY STUDIES FOR PRODUCING CRUDE LIPASE FROM TEMPE’S MOULD CULTIVATED IN RICE-HUSK-BASED SOLID MEDIA Teuku Beuna Bardant; Kiky Corneliasari Sembiring; Achmad Hanafi Setiawan
Indonesian Journal of Chemistry Vol 7, No 2 (2007)
Publisher : Universitas Gadjah Mada

The goal of these preliminary studies is to support Indonesian program for increasing palm oil added value through independent production technology based on Indonesian natural resources. Various palm oil derivatives could be synthesized enzymatically using lipase from microbes that available in Indonesia. Tempe's mould is available in abundance in Indonesia and had already been proved for producing lipase. This paper provides information about producing crude lipase from Tempe's mould cultivated in rice-husk-based solid media using palm oil as carbon source. Observed variables include solid media composition, optimum fermentation time, extraction and enriching process of crude lipase. The crude lipase was analyzed its hydrolysis activity on coconut oil and palm oil. The result of these preliminary studies shows that this production process is a simple and tough process and very potential to be developed.

SYNTHESIS AND CHARATERISATION OF RICE HUSK SILICA BASED BOROSILICATE (B2SiO5) CERAMIC BY SOL-GEL ROUTES Simon Sembiring
Indonesian Journal of Chemistry Vol 11, No 1 (2011)
Publisher : Universitas Gadjah Mada

In this research, borosilicate ceramics were produced from rice husk silica. Preparation of borosilicate ceramics was conducted by mixing boron oxide sol from borax with silica sol extracted from rice husk. The boron oxide was produced by hydrolysis of borax using H2SO4 5%. The samples were synthesized with different compositions, with the ratios of silica to boron oxide are 8:1, 8:2, 8:3 and 8:4. The samples were sintered at 900 °C. Functional groups were examined using FTIR spectroscopic technique. Structural and microstructural characteristics were examined by XRD and SEM, respectively. The chemical resistance of borosilicate is evaluated by gravimetric method using H2SO4, HCl, NaOH and KOH. The FTIR study revealed that the main functional groups are Si-O-Si, B-O-B, and B-O-Si. The x-ray diffraction (XRD) study revealed that the main crystalline phases are borosilicate (B2SiO5) and boron oxide (B2O3). SEM investigations clearly demonstrated that the smaller particle size was found with increasing in boron oxide concentration. From the chemical resistance test carried out, it was obtained that the produced borosilicate possessed high resistance to acids and alkalis.

CATALYTIC PERFORMANCES OF Fe2O3/TS-1 CATALYST IN PHENOL HYDROXYLATION REACTION Didik Prasetyoko; Cholifah Endah Royani; Hamzah Fansuri; Zainab Ramli; Hadi Nur
Indonesian Journal of Chemistry Vol 10, No 2 (2010)
Publisher : Universitas Gadjah Mada

Hydroxylation reaction of phenol into diphenol, such as hydroquinone and catechol, has a great role in many industrial applications. Phenol hydroxylation reaction can be carried out using Titanium Silicalite-1 (TS-1) as catalyst and H2O2 as an oxidant. TS-1 catalyst shows high activity and selectivity for phenol hydroxylation reaction. However, its hydrophobic sites lead to slow H2O2 adsorption toward the active site of TS-1. Consequently, the reaction rate of phenol hydroxylation reaction is tends to be low. Addition of metal oxide Fe2O3 enhanced hydrophilicity of TS-1 catalyst. Liquid phase catalytic phenol hydroxylation using hydrogen peroxide as oxidant was carried out over iron (III) oxide-modified TS-1 catalyst (Fe2O3/TS-1), that were prepared by impregnation method using iron (III) nitrate as precursor and characterized by X-ray diffraction, infrared spectroscopy, nitrogen adsorption, pyridine adsorption, and hydrophilicity techniques. Catalysts 1Fe2O3/TS-1 showed maximum catalytic activity of hydroquinone product. In this research, the increase of hydroquinone formation rate is due to the higher hydrophilicity of Fe2O3/TS-1 catalysts compare to the parent catalyst, TS-1.

“TERPI” AS A QUANTITY OF THERMODYNAMIC POTENTIAL ENERGY SUPPLEMENTARY TO THE CONCEPT OF WORK AND HEAT RHA Sahirul Alim
Indonesian Journal of Chemistry Vol 3, No 2 (2003)
Publisher : Universitas Gadjah Mada

Isothermal reversible thermodynamic processes were studied, where there will not occur flow of heat (q) in the system in accord with the second law of thermodynamic. It appear that the energy flow in the system cannot be explained adequately by considering the flow of P,V - work, usually indicated by w, in accordance with the first law, that is, ΔU = q + w with q = 0. Therefore, it is necessary to have another kind of work energy (potential) which is not electrical to explain such as the experiment of Boyle that results in the formula PV = C for a close ideal gas system undergoing an isothermal and reversible process. In this paper, a new work potential which is called ";;terpi";; is introduced, and is abbreviated as τ (tau) and defined as: dτ ≡ - T dSrev = - dqrev. Therefore, dt is also not an exact differential as dw and dq. For any isothermal reversible process, it can be written: τ = -TΔSrev, and for redox reaction, such as an electrochemical cell, it is noteworthy to distinguish between τ system (τsyst) and τ reaction (τr) which combine together to become an electrical work flow, (wel) done by the system on the surrounding, so that:ΔGr = τsyst + τr = v F E Furthermore, the studies of phase transitions, which occur isothermally, were also considered, e.g. the evaporation of a liquid into vapour at a certain T. The heat given to this process cannot freely flow isothermally, but first it must be changed into terpy and then added to the enthalpy of the vapour following the equation: τvap = -TΔSvap = -ΔHvap.

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