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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 14 Documents

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Search results for , issue "Vol 13, No 1 (2013)" : 14 Documents clear

Kinetics and Mechanism of Ni/Zeolite-Catalyzed Hydrocracking of Palm Oil into Bio-Fuel Sri Kadarwati; Fitri Rahmawati; Puji Eka Rahayu; Kasmadi Imam Supardi
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Kinetics and mechanisms of Ni/zeolite-catalyzed cracking reaction of methyl ester palm oil (MEPO) were studied using a continuous flow-fixed bed reactor system at an atmospheric pressure. The catalyst was prepared by wet impregnation method with a solution of nickel nitrate hexahydrate as the precursor and zeolite as carrier. The characteristics of catalyst including active Ni metal content, crystallinity, total acidity, and porosity were evaluated. The reactions were performed with a varied hydrogen flow rate as a carrier gas as well as a reductant and reaction time. Liquid products were analyzed by GC. Analysis by GC-MS was only conducted on a product at hydrogen flow rate with the best conversion. It has been shown that the catalyst has a superior character for hydrocracking reactions of MEPO into green fuel. No considerable effect of hydrogen flow rate on the total conversion was observed. The tests showed that the kinetics of Ni/zeolite-catalyzed cracking reaction followed pseudo-first order kinetics. GC-MS analysis revealed the formation of light hydrocarbon products with C6-C8 of aliphatic and cyclic components without oxygenates. Distribution of the product indicated that the cracking reaction as well as the isomerization of the products of hydrocracking occurred. Thus, Ni/zeolite-catalyzed cracking involved cracking /hydrogenation, isomerization, cyclization, and deoxygenation.

Vulcanization Kinetics of Natural Rubber Based On Free Sulfur Determination Abu Hasan; Rochmadi Rochmadi; Hary Sulistyo; Suharto Honggokusumo
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

The determination of free sulfur in the rubber vulcanizates provided significant representation of vulcanization reaction. In this research, the effects of vulcanization temperature, the mixing method of carbon black into rubber, the ingredients mixing sequence and the type of carbon black were studied on masticated and milled natural rubber in which the reaction was observed by un-reacted sulfur determination. The results showed that higher vulcanization temperature provided faster vulcanization reaction and greater reaction rate constant. Similarly, the mixing sequence of ingredient and carbon black into rubber influenced the rate of vulcanization reaction. The subsequent ingredients mixing sequence, in this case, resulted in higher vulcanization rate compared to that of the simultaneous one. However, the mixing method of carbon black into rubber brought small effect on the rate of vulcanization reaction. The type of carbon black applied was observed to influence the reaction rate of vulcanization. Smaller particle sizes of carbon black gave larger reaction rate constant. In this case, the type of carbon black N 330 gave faster vulcanization rate than that of N 660.

Effect of Non Ionic Surfactant Addition to Cellulase Performance in High-Substrate-Loading-Hydrolysis of Palm Oil EFB and Water-Hyacinth Teuku Beuna Bardant; Sudiyarmanto Sudiyarmanto; Haznan Abimanyu; Aisha Kania Hanum
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Enzymatic hydrolysis with high substrate loading of palm oil (Elaeis guineensis) empty fruit bunch (EFB) and water-hyacinth (Eichhornia crassipes) were investigated as a prior part of ethanol production from lignocelluloses. Commercial surfactant Span 85 and Tween 20 were used as cellulase performance enhancer in hydrolysis process with substrate loading above 20% (w/w). Cellulase performances were compared based on hydrolysis conversion. Hydrolysis conversions of EFB using cellulase with concentration 10 and 15 FPU/g-substrate was 38.55% and 88.80% respectively. Addition 2% (v/v) of Tween 20 to EFB hydrolysis reaction with cellulase concentration 10 FPU/g-substrate gave the conversion 87.30%. This addition enhance the cellulase performance up to 226.5% or similar with the performance of cellulase 15 FPU/g substrate. Addition 2% (v/v) of Span 85 to the similar reaction only enhances cellulase performance to 174.7%. Hydrolysis conversion of boiling-pretreated water-hyacinth and autoclave-pretreated water-hyacinth using cellulase 15 FPU/g-substrate was 45.84% and 52.29% respectively. Addition 2% (v/v) of Tween 20 and Span 85 to boiling-pretreated water-hyacinth hydrolysis with cellulase concentration 15 FPU/g-substrate enhance cellulase performance of 128.9% and 153.5% respectively. Addition 1% (v/v) of Tween 20 and Span 85 to the similar reaction with cellulase concentration 10 FPU/g-substrate gave conversions 51.00% and 53.79% respectively, or similar with conversion of autoclave-pretreated water-hyacinth hydrolysis with 15 FPU/g-substrate.

Design of New Potent Insecticides of Organophosphate Derivatives Based on QSAR Analysis Mudasir Mudasir; Yari Mukti Wibowo; Harno Dwi Pranowo
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Design of new potent insecticide compounds of organophosphate derivatives based on QSAR (Quantitative Structure-Activity Relationship) analytical model has been conducted. Organophosphate derivative compounds and their activities were obtained from the literature. Computational modeling of the structure of organophosphate derivative compounds and calculation of their QSAR descriptors have been done by AM1 (Austin Model 1) method. The best QSAR model was selected from the QSAR models that used only electronic descriptors and from those using both electronic and molecular descriptors. The best QSAR model obtained was:Log LD50 = 50.872 - 66.457 qC1 - 65.735 qC6 + 83.115 qO7 (n = 30, r = 0.876, adjusted r2 = 0.741, Fcal/Ftab = 9.636, PRESS = 2.414 x 10-6)The best QSAR model was then used to design in silico new compounds of insecticide of organophosphate derivatives with better activity as compared to the existing synthesized organophosphate derivatives. So far, the most potent insecticide of organophosphate compound that has been successfully synthesized had log LD50 of -5.20, while the new designed compound based on the best QSAR model, i.e.: 4-(diethoxy phosphoryloxy) benzene sulfonic acid, had log LD50 prediction of -7.29. Therefore, the new designed insecticide compound is suggested to be synthesized and tested for its activity in laboratory for further verification.

Effect of Gamma Irradiation on Mechanical and Thermal Properties of Fish Gelatin Film Isolated from Lates Calcarifer Scales Dian Pribadi Perkasa; Erizal Erizal; Darmawan Darmawan; Akhmad Rasyid
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

The objective of this research was to investigate the effect of gamma irradiation on mechanical and thermal properties of fish gelatin films prepared from scales of Lates calcarifer. The films were irradiated by gamma rays at varied doses (0-50 kGy). The mechanical and thermal properties of irradiated gelatin films were measured by using colorimeter, Universal Testing Machine, Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared (FTIR) spectrophotometer. The results showed that increasing of irradiation dose up to 50 kGy, the color of irradiated film did not change significantly (p < 0.05). The tensile strength of irradiated film was increased with no differences among dose variation but there was no change on elongation at break value (p < 0.05). The DSC spectra of irradiated gelatin films showed that irradiation did not affect melting temperature (Tm). In contrast, the glass transition temperature (Tg) of irradiated film has slight tendency to increase with increasing of radiation doses. In general, the FTIR spectra confirmed that gamma irradiation up to 50 kGy affected the mechanical properties of gelatin films.

The Acid Catalyzed Reaction of α-Pinene Over Y-Zeolite Nanik Wijayati; Harno Dwi Pranowo; Jumina Jumina; Triyono Triyono
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

The hydration of α-pinene has been studied in the presence of Y-zeolite (Si/Al = 2.89) as a solid acid catalyst. The reaction was performed in batch reactor in isopropyl alcohol at various temperature and reaction time with magnetic stirrer. The acid catalyst hydration reaction of a-pinene yields a complex mixture of monoterpenes, alcohols and hydrocarbons. The selectivity of α-terpineol (the monocyclic alcohol) as main product was 59.20% with a conversion of 83.83% and the non alcoholic as the isomerization co-product as 30% after 60 min at 65 °C. The conversion and selectivity to α-terpineol increase significantly with in increase in temperature and reaction times.

Syntheses of Azo-Imine Derivatives from Vanillin as an Acid Base Indicator Bambang Purwono; Chairil Anwar; Ahmad Hanapi
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Preparations of azo, imine and azo-imine derivatives from vanillin as an indicator of acid-base titration have been carried out. The azo derivative of 4-hydroxy-3-methoxy-5-(phenylazo)benzaldehyde 2 was produced by diazotitation reaction of vanillin in 37.04% yield. The azo product was then refluxed with aniline in ethanol to yield azo-imine derivatives, 2-methoxy-6-(phenylazo)-4-((phenylimino)methyl)phenol 1 in 82.21% yield. The imine derivative, 2-methoxy-4-((phenylimino)methyl)-phenol 3 was obtained by refluxing of vanillin and aniline mixture in ethanol solvent and produced 82.17% yield. The imine product was then reacted with benzenediazonium chloride salt. However, the products indicated hydrolyzed product of 4-hydroxy-3-methoxy-5-(phenylazo)benzaldehyde 2 in 22.15% yield. The 2-methoxy-4-((phenylimino)methyl)phenol 2 could be used as an indicator for titration of NaOH by H2C2O4 with maximum concentration of H2C2O4 0.1 M while the target compound 1 could be used as titration indicator for titration of NaOH with H2C2O4 with same result using phenolphthalein indicator.

The Optimum Reaction Time, Activation Energy and Frequency Factor of Methyl Ricinoleate Nitration Abdullah Abdullah; Triyono Triyono; Wega Trisunaryanti; Winarto Haryadi
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Determination of the optimum reaction time, activation energy (Ea) and frequency factor (A) of methyl ricinoleate nitration has been done. The nitration was conducted with the mole ratio of methyl ricinoleate to HNO3 of 1:15. The reaction was conducted at temperatures of 29 and 64 °C with a variation of reaction time for 10, 20, 30, 60, 90, 120, and 150 min. Determination of activation energy and frequency factor was performed in a temperature of 29, 33, 38, 44, 49, 57 and 64 °C. The results showed that the optimum reaction time is 90 min. The activation energy (Ea) and frequency factor (A) was 44.5 kJ/mol and 4.780 x 103 sec-1, respectively.

Synthesis of Cassava Waste Pulp-Acrylamide Super Absorbent: Effect of Initiator and Cross-Linker Concentration Zainal Alim Mas’ud; Mohammad Khotib; Nurmutia Sari; Anwar Nur
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

Cassava waste pulp (CWP) contains high carbohydrates that can be modified into super absorbent polymer (SAP) through grafting and cross-linking copolymerization. Acrylamide (AM) was grafted onto CWP with ammonium persulfate (APS) as the initiator and N,N'-methylene-bis-acrylamide (MBA) as the cross-linker under atmospheric nitrogen. The effect of APS and MBA concentrations on water absorption capacity of saponified SAP was studied, while the evaluation of grafting ratio (GR) and grafting efficiency (GRE) was conducted on unsaponified SAP. The grafting success was indicated by the occurrence of IR peaks at wave numbers of 573, 765, 858, and 1667 cm-1. In the saponified SAP, the very intense characteristic band at 1562 cm-1 is due to C=O asymmetric stretching in the carboxylate anion. Saponification increases significantly water absorption capacity compared to that of unsaponified SAP (from 39.79 g/g to 578.23 g/g). The highest water absorption capacity is reached at 0.74% APS and 0.09% MBA. The percentage of GRE and GR tends to increase with increasing APS concentration until reaching the highest value and then decreases. Effect of MBA concentration on water absorption capacity, GR, and on GRE is similar to the effect of initiator concentration on GR and GRE.

The Fermentation of Green Algae (Spirogyra majuscule Kuetz) using Immobilitation Technique of Ca-Alginate for Saccharomyces cerevisiae Entrapment Atmanto Heru Wibowo; Lailatul Mubarokah; Adhitasari Suratman
Indonesian Journal of Chemistry Vol 13, No 1 (2013)
Publisher : Universitas Gadjah Mada

A study of batch fermentation of green algae (Spirogyra majuscula Kuetz) from Pengging Lake, Boyolali, Central Java for bioethanol source using immobilization technique of Ca-alginate for Saccaromyces cerevisiae entrapment has been done. The scope of the study emphasized on the best condition for the processes of hydrolysis and fermentation. Concentration of sulfuric acid and hydrolysis time were varied with 0.1, 0.2, 0.3, 0.4 and 0.5 M for 30, 90, 150, 210, 270, 330, 360, 390, 420, and 450 min to obtain the maximum glucose content of UV analysis. Na-alginate : yeast ratio and fermentation time were varied with 1:5, 2:4, 3:3, 4:2 and 5:1 (w/w) for 1, 2, 3, 4, 5, 6 and 7 days. Distillation at 70-80 °C was deployed to purify the fermentation product. The ethanol content in the product was analyzed using gas chromatography-flame ionization detector (GC-FID). The result of study showed that maximum glucose content was obtained 2.1% from 0.2 M sulfuric acid for 6 h of hydrolysis. Maximum ethanol content was obtained 54.1% from 2:4 ratio of Na-alginate : yeast (w/w) for 4 days of fermentation. The study also concludes that immobilization technique of Ca-alginate increase alcohol content compared to without immobilization of green-algae fermentation.

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