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The Journal of Pure and Applied Chemistry Research
Published by Universitas Brawijaya
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Core Subject : Science,
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Articles 6 Documents
Search results for , issue " Vol 4, No 1 (2015)" : 6 Documents clear
Mild and Efficient Reagents for Oxidation of Alcohols: [MeOCH2(Ph)3P]+[CrO3X]Ö¿, (X=F, Cl) Lashgari, Amir; Ghamami, Shahriar
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.190

Abstract

Two fast, mild, and reasonable oxidizing agents, Methoxymethyltriphenylphosphonium Halochromates (VI), [MeOCH2(Ph)3P]+ [CrO3X]ֿ (MMTriPPXC) are synthesized. The preparations of Methoxymethyltriphenylphosphonium Halochromates are new and efficient reagents for the oxidation of primary and secondary alcohols to their corresponding carbonyl compounds in dichloromethane at ambient temperature. These are obtained with relatively short reaction times.  The oxidants/substrates ratios of 1:1 are employed.
Determination of Hydroquinone in a Square Wave Voltammetry based on Screen Printed Carbon Electrode Safitri, Alfita; Mulyasuryani, Ani; Tjahjanto, Rachmat Triandi
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.187

Abstract

Hydroquinone is a phenolic compound are often used extensively in the cosmetics industry as whitening agent. This compound is very toxic and their use should be monitored. Due to the impact of hydroquinone, the use of hydroquinone restricted by BPOM (Food and Drug Regulatory Department in Indonesia) maximum by 0.02%. The aim of this study was to establish a new simple sensitive voltammetry method for determination of hydroquinone using screen printed carbon electrode (spce). In this study, linear concentration range, limit of detection, sensitivity and accuracy were investigated. Before the determination of parameters analysis, the method require the optimization of method parameters such as frequency and pulse height. This study were showed that the measurement of hydroquinone with square wave voltammetry method has linear concentration range 1 - 100µM, limit of detection 23.4µM, sensitivity 0.075µM/µA and accuracy 0.9969. The proposed method was succesfully applied in whitening cream cosmetic samples with good enough results.
Catalytic Desulfurization of Benzothiophene Using Keggin Type Polyoxometalates as catalyst Lesbani, Aldes; Marpaung, Arianti; Verawaty, Marieska; Amalia, Hesti Rizki; Mohadi, Risfidian
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.202

Abstract

Performance of catalytic desulfurization of benzothiophen (BT) was studied using polyoxometalates as catalyst. Polyoxometalates H3[a-PW12O40] and  H4[a-SiW12O40], have different heteroatom in Keggin structure and catalytic activities. Polyoxometalates H3[a-PW12O40] and  H4[a-SiW12O40] have high crystallinity with homogeneous distribution particles. Desulfurization of BT using polyoxometalates H3[a-PW12O40] and H4[a-SiW12O40] resulted % conversion up to 99% for 3 h reaction time and at temperature 40 oC. Application of polyoxometalates H3[a-PW12O40] and H4[a-SiW12O40] for crude oil desulfurization showed % conversion of 4-88%. The main functional groups of polyoxometalates still retained after catalytic desulfurization indicated the stability of polyoxometalate compounds
Influence of Dye Adsorbtion Time on TiO2 Dye-Sensitized Solar Cell with Krokot Extract (Portulaca Oleracea. L) as A Natural Sensitizer. Krisdiyanto, Didik; Khuzaifah, Siti; Khamidinal, Khamidinal; Sedyadi, Endaruji
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.203

Abstract

Dye sensitized solar cells (DSSC) photoelectrodes were fabricated using titanium oxide (TiO2) and sensitized with the krokot extract dye. This study investigated the effect of dye adsorbtion time to an efficiency of the solar cells. The fabrication cells immersed with krokot extract dye for 1, 8 and 26 hours. The photochemical performance of the DSSC showed that the open circuit voltage (Voc) were 0.33, 0.036 and 0.27 V with short photocurrent density (Isc) 8.00 x 10-5, 6.80 x 10-7 and 3.10 x 10-4. The photo-to-electric conversion efficiency of the DSSC reached 4.63 x 10-3 % for 26 hours adsorbtion time.
Alumina-Activated Carbon Composite as Adsorbent of Procion Red Dye from Wastewater Songket Industry Hariani, Poedji Loekitowati; Fatma, Fatma; Zulfikar, Zulfikar
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.206

Abstract

Alumina-activated carbon composite has been synthesized and studied for adsorption procion red dye. Composite was prepared by precipitation method aluminium hydroxide on the surface of activated carbon followed by calcinations. The Fourier transform Infra Red (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) and Brunaeur Emmet Teller (BET) surface are being used to characterize the adsorbent. Batch adsorption experiments were carried out for the adsorption of procion red dye. Effect of the mass of composite, stirrer speed, contact times and pH of the solution on the adsorption capacity were studied. The obtained optimum conditions applied to adsorp of procion red dye from wastewater songket industry. The result showed that the adsorption optimum at mass of alumina-activated carbon composite 0.1 g, stirrer speed 150 rpm, contact times 2 hours at pH of the solution 9. The adsorption isotherm data according to Langmuir isotherm. The alumina-activated carbon composite can be removal of procion red dye from wastewater songket industry with effectiveness adsorption of 88.21 %.
Development of Spectrophotometric Method for Determination of Chromium Species Using Hypochlorite Agent Based on the Formation of Cr(VI)-Diphenylcarbazide Complex Suryati, Lilik; Sulistyarti, Hermin; Atikah, Atikah
The Journal of Pure and Applied Chemistry Research Vol 4, No 1 (2015)
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2015.004.01.183

Abstract

Research of speciation analysis Cr(III) and Cr(VI) using hypochlorite and peroxide oxidants with Visible Spectrophotometry has been proposed. This research was carried to obtain optimum conditions of oxidation process Cr(III) into Cr(VI) and the formation of Cr(VI)-Diphenylcarbazide complex to the wavelength, complexing time, oxidizing agent (oxidant) concentration, oxidation temperature, pH, and the influence of foreign ion, so it can be proposed as an alternative method for speciation analysis of Cr(III) and Cr(VI). Optimization results show that the maximum wavelength of Cr(VI)-diphenylcarbazide complex is 542 nm by the stable complex time 16-30 minutes using a hypochlorite (HOCl) oxidant concentration 1 x 10-3 M, temperature 60 oC and pH 1. This method is compared with standard method. The presently developed method is more simple and faster than standard method. Regarding accuracy and precision, the method is quite comparable with the standard methods.Key words: speciation, Cr(III), Cr(VI), oxidant, hypochlorite, spectrophotometry VIS

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