Volume 1, Issue 2, September 1998
CONTENTSNon-isothermal dissolution kinetics of chromite in alkaline aqueous solution(1998) Volume(issue) 1(2): 57-60.
A. Demirbaş and Y. Abalı
1Department of Science Education, Karadeniz Technical University, 61335 Akçaabat, Trabzon, Turkey
2Department of Chemistry, Celal Bayar University, Manisa, Turkey
The dissolution kinetics of chromite in aqueous KOH solution was studied in the present work. In the experiments, stirring time, stirring speed, particle size, solid-to-liquid ratio, and temperature were chosen as dissolution parameters. It was observed that decrease of the particle size, the solid-to-liquid ratio and increase of the dissolution temperature increased the leaching rate, and the stirring speed has no significant effect on the reaction rate. The dissolution kinetic parameters were the activation energy 61598 J mol-1 , the pre-exponential factors; 4.38 x 1013 min-1 , and rate constant values 1.55x103 min-1.
Optimization of dissolution of calcinated bone in HCl solutions (1998) Volume(issue) 1(2): 61-66.
Y. abalı and E. Mert
Celal Bayar University Faculty of Arts and Science Department of Chemistry 45030 Manisa , Türkiye
In this study, the optimum conditions of dissolution of calcinated bone in HCl solutions with different concentrations are investigated. Using the Taguchi Fractional Design Method, it was found that the optimum process conditions, at which 67.2 % P2O5 dissolution was reached, were as follows: Reaction temperature : 318 K, solid-to-liquid ratio: 1/5 (g/ml), acid concentrations :32 (% w/v), stirring speed :400 min-1 and reaction time: 60 min.
Dissolution kinetics of calcinated magnesite in acetic acid solutions(1998) Volume(issue) 1(2): 67-74
Department of Chemistry, Celal Bayar University, Manisa, Turkey
In this study, magnesite mineral supplied from Erzurum-Pasinler (Turkey) and contained 97.35% MgCO3 was firstly calcinated at 850oC for an hour and dissolved in acetic acid solutions. The effects of temperature, solid-to-liquid ratio, reaction time, stirring speed and acid concentration on to dissolution rate of calcined magnesite (magnesia) in acetic acid was investigated. It was observed that the dissolution of magnesia increased with increasing temperature, stirring speed, reaction time and acid concentration and decreasing with solid-to-liquid ratio. It was determined that the dissolution process is controlled by pseudo first-order reaction rate. Activation energy for the reaction was calculated 8.78 kJ/mol.
Variations of water quality in Lake Kovada and its waterway (1998) Volume(issue) 1(2): 75-78
R. Atay1 and M. Cengiz2
1Eğirdir Fisheries Faculty, Süleyman Demirel University, Eğirdir, Isparta, Turkrey
2Department of Chemistry, Süleyman Demirel University, Isparta, Turkey
This work contains some analysis parameters, farming water quality and water pollution in Lake Kovada and its waterway. The analyses of taking samples from certain stations in the lake and its waterway were periodically carried out monthly. The basis of using tests composed of some fundamental parameters such as temperature, oxygen soluble in water, pH, conductivity, alkalinity, determination of calcium, magnesium, chloride, nitrate, phosphate, ammonia and organic substance. The results were compared with the results of the studies conducted in other lakes in the same region at different times. In the end, necessary precautions have been suggested by determining sources of pollution in three Lake Kovada.
New penicillin and ampicillin derivatives (1998) Volume(issue) 1(2): 79-82
Department of Chemistry, Celal Bayar University, Manisa, Turkey
New penicillin derivatives have been synthesized by condensation of mono-substituted cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) with 6-amino penicillanic acid or ampicillin, and screened for their antibacterial activity against S. aureus, E.coli, K. Pneumonae, S. typhi and P. aeruginosa at 500 g/L concentration. Some compounds are active against all the tested micro-organisms.
Examination of phenols in humic acid by GC-MS hyphenated technique (1998) Volume(issue) 1(2): 83-92.
A. Okudan, H. Kara, Y. Çengeloğlu and F. Nizamlıoğlu
University of Selçuk, Faculty of Arts and Sciences, 42079 Campus, Konya-Türkiye
The phenolic compounds, in humic acid extracted from Ilgın Lignite by alkaline extraction was determined by gas chromatography-mass spectrometry. Two temperature gradient programming have been applied. The 14 and 9 (totally 21 because 2 phenolic compounds are in both fractions ) phenolic compounds in two fraction extracted at two different pH (7.5 and 8.3) from humic acid, respectively, were isolated. Most of them have not been, previously, found out in coal derivatives. The separation and identification of phenolic compounds were verified by analysis of the GC-MS and comparisons of the retention time and mass spectra with standards phenolic compounds under computer control were made automatically. Thus the confidence level of this analysis is high The used methods in this work provide a comprehensive separation and identification scheme for phenols in complex samples. such as humic acid.
Solvent fractionation of humic acids from Central Anatolian lignites (1998) Volume(issue) 1(2): 93-101.
H. Kara and R. Mirzaoğlu
Selçuk University, Department of Chemistry, Konya, Turkey.
From three different specimens of Central Anatolian lignites, humic acid (HA) were extracted with 2.5% NaOH. Acid washing were used to remove residual caustic from the treated coal. The HA yields extracted from Beyşehir, Ilgın and Ermenek lignites were 32.3%, 25.8% and 21.3% of the coal on dry basis respectively. HA could not be extracted from Dadağı lignite. This might be due to the higher quality rank of this coal. Based on the rank of coals the weight of extracted HA decreased. The general characterization of HA obtained from Beyşehir, Ilgın and Ermenek lignites and some fractions extracted from HA with different solvents were examined. The oils (hexane soluble), asphaltenes (benzene soluble), preasphaltenes (tetrahydrofuran (THF) soluble) and pyridine soluble parts of HA were separated. The HA from Beyşehir lignites is composed of 1,2% oil, 8,5% asphaltenes, 18.4% preaspaltene, 40.1% higher molecular weight (pyridine soluble) and 31.8% non soluble parts. The yields of pyridine extracts obtained from untreated HA were about 71.8%, 64,9% and 60,8% of HA from Beyşehir, Ilgın and Ermenek lignites. The pyridine soluble fractions extracted from untreated HA by a soxhlet extractor were subjected to column chromatography utilizing activated silica gel as the adsorbent and hexane, benzene, methanol and THF as eluents. The eluates of each solutions were separately examined for their compositions.
Influences of lignite ash additives on strength, setting, expansion, and hydration properties of cement (1998) Volume(issue): 1(2): 102-110.
A. Aslan1, F. Ö. Karataş2 and A. Demirbaş2
1Department of Chemistry, Celal Bayar University, Manisa, Turkey; 2Fatih Education Faculty, Karadeniz Technical University, 61335 Akçaabat, Trabzon, Turkey.
In this study, physical and chemical properties of lignite fly ashes obtained electrofilter from (FAE) and cyclone (FAC), lignite bottom ash (BA), cement+lignite ash mixtures and their effects on stregth, setting, volume expansion, and hydration properties of concrete were investigated. The ashes were classified into two general types based on total silica, alumina, and iron-III oxide: Class C and Class F. The results obtained were compared with the Turkish Standards, in general, were found to be within the limits. As a result, the lignite fly and bottom ash additives can be used as In this study cementitious materials.
Acetic acid, methanol and acetone from lignocellulosics by pyrolysis (1998) Volume(issue) 1(2): 111-115.
A. Demirbaş and D. Güllü
Educational Faculty, Black Sea Technical University, 61335 Akçaabat, Trabzon, Turkey
Thermal depolymerization and decomposition of biomass, cellulose, hemicelluloses, and lignin were formed various products as well as a solid residue of charcoal. A promising route for processing biomass is the pyrolysis which has been conducted under a variety of experimental conditions resulting in production charcoal, tarry material, aqueous fraction, and gaseous products. Acetic acid mainly comes from the acetyl groups of the hemicelluloses. The pyroligneous acid consists of about 50 % methanol, 18 % acetone. Levoglucosan is also sensitive to heat and decomposes to acetic acid, acetone, phenols, and water. Methanol arises from methoxyl groups of uronic acid.