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Iqmal Tahir

Chemistry Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta

Author-ID : 3959541

Chemical Engineering, Chemistry & Bioengineering Chemistry

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EFFECT OF Cr(VI) IONS ON THE EFFECTIVENESS OF CHLOROPHENOL PHOTODEGRADATION Endang Tri Wahyuni; Ngatidjo Hadipranoto; Iqmal Tahir; Bambang Haryo Gatut Tamtama
Indonesian Journal of Chemistry Vol 4, No 3 (2004)
Publisher : Universitas Gadjah Mada

In order to solve environmental problems due to chlorophenol compound and which is hazardous and carcinogenic, the effect of Cr(VI) ions on the chlorophenol photodegradation effectiveness has been evaluated. Photodegradation process was carried out in a closed reactor by batch sistem, by exposing the UV lamp into a solution containing chlorophenol and Cr(VI) ions for a period of time. Then the solution was analyzed by gas chromatography for determination of the residual chlorophenol concentration. In this research, the influences of reaction time, Cr(VI) ions concentration, and solution pH on the photodegradation results were also evaluated. The research results indicated that the effectiveness of the photodegradation increases when ion Cr(VI) was added. The improvement of the effectiveness is proportional with the increase of the concentration of Cr(VI) added. The effectiveness of the photodegradation is also influenced by solution pH, and the highest is reached at pH < 2. Chlorophenol photodegradation follows first order reaction. The respective rate reaction constants for chlorophenol photodegradation in the absence and in the presence of Cr(VI) ions are 4.91x 10-2 and 11.41x 10-2 hours-1

UTILIZATION OF ACTIVATED ZEOLITE AS MOLECULAR SIEVE IN CHROMATOGRAPHIC COLUMN FOR SEPARATION OF COAL TAR COMPOUNDS Dwi Retno Nurotul Wahidiyah; Bambang Setiaji; Iqmal Tahir
Indonesian Journal of Chemistry Vol 4, No 2 (2004)
Publisher : Universitas Gadjah Mada

Application of activated zeolite (ZAA) as molecular sieve to separate compounds of coal tar from vaccum fractional distillation, have been done. The size of zeolite was 10-20 mesh and used as solid phase in column chromatography with length of 30 cm. The first step of the research was coal pyrolisis and the product (tar) was distillated by fractional column and vaccum system at reduced pressure 44 cmHg and maximum temperature at 200 oC. The distillate from this procedure was flowed to the column chromatography of zeolite (ZAA). The compound absorbed by zeolite was eluted with varying solvents, i.e: CCl4, acetone and ethanol. Each fraction was then analyzed by gas chromatography. The results showed, zeolite have a capability to separate the compounds of tar and it tends to absorb medium hydrocarbon. The nonpolar eluent [CCl4] gives the better result in eluting tar compound than polar (ethanol) or medium polar eluents (acetone).

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.

QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP ANALYSIS OF CURCUMIN AND ITS DERIVATIVES AS GST INHIBITORS BASED ON COMPUTATIONAL CHEMISTRY CALCULATION Enade Perdana Istyastono; Sudibyo Martono; Harno Dwi Pranowo; Iqmal Tahir
Indonesian Journal of Chemistry Vol 3, No 3 (2003)
Publisher : Universitas Gadjah Mada

The Quantitative Structure-Activity Relationship (QSAR) study was established on curcumin and its derivatives as glutathione S-transferase(s) (GSTs) inhibitors using atomic net charges as the descriptors. The charges were resulted by semiempirical AM1 and PM3 quantum-chemical calculations using computational chemistry approach. The inhibition activity was expressed as the concentration that gave 50% inhibition of GSTs activity (IC50). The selection of the best QSAR equation models was determined by multiple linear regression analysis. This research was related to the nature of GSTs as multifunctional enzymes, which play an important role in the detoxification of electrophilic compounds, the process of inflammation and the effectivity of anticancer compounds.The result showed that AM1 semiempirical method gave better descriptor for the construction of QSAR equation model than PM3 did. The best QSAR equation model was described by :log 1/IC50 = -2,238 - 17,326 qC2' + 1,876 qC4' + 9,200 qC6'The equation was significant at 95% level with statistical parameters : n = 10, m = 3, r = 0,839, SE = 0,254, F = 4,764, F/Ftable = 1,001.

STUDY OF DOUBLE PROTONS MIGRATION MECHANISM IN SUPRAMOLECULAR STRUCTURES OF ACETIC ACID-WATER AND ACETIC ACID-AMMONIA BY AB INITIO METHOD Karna Wijaya; Iqmal Tahir; Harnowo Harnowo
Indonesian Journal of Chemistry Vol 3, No 2 (2003)
Publisher : Universitas Gadjah Mada

The theoretical study of double protons migration mechanism on acetic acid-water and acetic acid-ammonia associations has been carried out. The research covered determinations the reactant, transition state and product structures. To gain the goal, the research was conducted in three steps, i.e. (i) designing the reactant, transition state and product models, (ii) optimizing of structures, and (iii) calculating of their uncorrected total energy and frequencies with ab initio methods (basis set 6-31G**). All calculations were performed using Hyperchem ver 5.0 for Windows and Gaussian 94W package program. The computational study result showed that the calculated structures were in good agreement with the hypothetical structures.

QUANTITATIVE STRUCTURE AND ACTIVITY RELATIONSHIP ANALYSIS OF 1,2,4-THIADIAZOLINE FUNGICIDES BASED ON MOLECULAR STRUCTURE CALCULATED BY AM1 METHOD Mudasir Mudasir; Iqmal Tahir; Ida Puji Astuti Maryono Putri
Indonesian Journal of Chemistry Vol 3, No 1 (2003)
Publisher : Universitas Gadjah Mada

Quantitative structure-Activity relationship (QSAR) analysis of fungicides having 1,2,4-thiadiazoline structure based on theoretical molecular properties have been done. Calculation of the properties was conducted by semiempirical method AM1 and the activity of the compounds was taken from literature. Relationship analysis between fungicides activity (pEC50) and molecular properties was done using SPSS program. The QSAR analysis gave the best model as follows: pEC50 = 3.842 + (1.807x10-4) ET + (5.841x10-3) Eb - (5.689x10-2) DHf -0.770 log P + 1.144 a - 0.671 m + 9.568 GLOB - (5.54x10-2) MR. n=19 r=0.917 SE=0.216 Fcal/Ftable=2.459 PRESS=0.469. The best model obtained was then used to design and predict the fungicides activity of new compounds derived from 1,2,4-thiadiazoline.

THE SYNTHESIS OF Cr2O3-PILLARED MONTMORILLONITE (CrPM) AND ITS USAGE FOR HOST MATERIAL OF p-NITROANILINE Karna Wijaya; Iqmal Tahir; Ahmad Baikuni
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

The synthesis of Cr2O3-pillared montmorillonite (CrPM) and its usage for host material of p-nitroaniline have been conducted. The Cr2O3-pillared montmorillonite clays was prepared by a direct ion exchange method. First, the polyhydroxychromium as a pillaring spesies was intercalated into the interlayer region of the montmorillonite clays (purified clay in the monocation form), result in a montmorillonite-polyoxychromium intercalation compound. The precursors/pillaring spesies was not stable, hence it must be stabilized by calcination in order to transform the polyoxychromium via dehydration and dehydroxylation processes into Cr2O3. This oxide constituts the so-called pillar that prop the clay layers apart to a relatively large distance. The Cr2O3-pillared clays as a host material was added into ethanol solution saturated with p-nitroaniline, and mixture was stirred for 24 h at room temperature. The Na-montmorillonite, Cr2O3-pillared clay and p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM) were characterized by X-Ray Diffraction (XRD), Gas Sorption Analysis, Infrared Spectroscopy (FTIR) and Activated Neutron Analysis (ANA) methods. The result of research showed that basal spacing (d001) of Cr2O3-pillared montmorillonite (CrPM) was 18,55 Å, meanwhile the basal spacing of the hydrated Na-montmorillonite was 14,43 Å. The specific surface area of the Cr2O3-pillared montmorillonite was 174,308 m2/g, whereas p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM) was 133,331641 m2/g. This fact indicated that p-nitroaniline has been included into the pore of the Cr2O3-pillared clay.

SYNTHESIS OF 3,4-DIMETHOXY ISOAMYL CINNAMIC AS THE SUNSCREEN COMPOUND FROM CLOVE OIL AND FUSEL OIL Tutik Dwi Wahyuningsih; Tri Joko Raharjo; Iqmal Tahir
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

Synthesis of sunscreen compound 3,4-dimethoxy isoamyl cinnamic from clove oil and fusel oil has been done. The majoring component of clove oil that is eugenol has been isolated, followed with several chemical processes i.e. isomerization into isoeugenol, oxidation of the product to change into vanillin, then modification vanillin into veratraldehyde. From the fusel oil, we isolate isoamyl alcohol and modified by acetylation into isoamyl acetic. The final product could be produce by Claissen's condensation of isoamyl acetic and veratraldehyde to give 3,4-dimethoxy isoamyl cinnamic. All of the processes are followed with structure characterization using GC, IR, GC-MS and 1H-NMR spectroscopy. The result shown that compound has 46.98% purity and potent as the UV-B sunscreen's type (lmax = 313 nm). In-vitro sunscreen's activity of the compound was tested by UV-Vis spectrophotometry and resulting a maximum Sun Protection Factor value (SPFin-vitro) at low concentration, 10.25 mg/mL.

MODELING OF ALKYL SALICYLATE COMPOUNDS AS UV ABSORBER BASED ON ELECTRONIC TRANSITION BY USING SEMIEMPIRICAL QUANTUM MECHANICS ZINDO/s CALCULATION Iqmal Tahir; Karna Wijaya; Titik Subarni
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

Modeling of several alkyl salicylates based on electronic transition by using semiempriical mechanical quantum ZINDO/s calculation has been done. Object of these research were assumed only alkyl salicylates of C4 (butyl) until C8 (octyl) homologue with 4-7 example structures of each homologue. All of the computation have been performed using quantum chemistry - package software Hyperchem 6.0. The research covered about drawing each of the structure, geometry optimization using semiempirical AM1 algorithm and followed with single point calculation using semiempirical ZINDO/s technique. ZINDO/s calculations used a defined criteria that is singly excited - Configuration Interaction (CI), gap of HOMO-LUMO energy transition was 2 and degeneracy level was 3. Analysis of the theoretical spectra was focused in the UV-B (290-320 nm) and UV-C (200-290 nm) area. The result showed that modeling of the compound can be used for predicting the type of UV protection activity depending with the electronic transition in the UV area. Modification of the alkyl homologue relatively did not change the value of wavelength absorbtion to indicate the UV protection activity. Alkyl salicylate compounds were predicted as UV-C sunscreen or relatively the compounds have protection effect for UV-C.

A ROBUST EIGHT–MEMBERED RING MOTIF IN THE HYDROGEN-BONDED STRUCTURE OF -(PHENYLAMINO)PYRIDINIUM- DI(METHANESULFONYL)AMIDATE Karna Wijaya; Iqmal Tahir; Armand Blaschette; Oliver Mours; Peter G Jones
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

The compound was prepared by dissolving 2-(phenylamino)pyridine (0.52 g ; 3.0 mmol) and di(methanesulfonyl)amine (0.51 g; 3.0 mmol) in 5 mL methanol. Slow partial evaporation of the solvent at low tempertaure (-30 oC) gave a yield of 0.66 g (64%) and crystals suitable for X-ray study (m.p. 150-152 oC). The single crystal X-ray result showed that the crystal system was trikline with space group P1. The crystal structure of the title compound 2-(phenylamino)pyridinium-di(methane-sulfonyl)amidate forms a robust antidromic ring motif type R228. The structure testifies to the persistence of the R228 in question, which was previously detected as a robust supramolecular synthon in 2-aminopyridinium di(benzenesulfonyl)amidate and in a series of onium di(methane-sulfonyl)amidates.

Co-Authors Ahmad Baikuni Armand Blaschette Bambang Haryo Gatut Tamtama Bambang Setiaji Dwi Retno Nurotul Wahidiyah Eko Sugiharto Enade Perdana Istyastono Endang Tri Wahyuni Harno Dwi Pranowo Harnowo Harnowo Ida Puji Astuti Maryono Putri Ika Liawati Karna Wijaya Mudasir Mudasir Ngatidjo Hadipranoto Oliver Mours Peter G Jones Sudibyo Martono Titik Subarni Tri Joko Raharjo Tutik Dwi Wahyuningsih

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