N. Sharmila, R. Rao, B. B. Hari, G. Trimurtulu, P. Satyanarayana
A kinetic study was carried out using spectrophotometric approach on the oxidation of nine differently substituted 2-aryl-trans-decahydroquinolin-4-ones by Cetyltrimethylammonium dichromate (CTADC) as oxidant at 30°C and in aqueous acetic acid (50%) containing catalytic amount of sulphuric acid (6N). The reactions were studied at 350 nm. The reaction was found to follow second order kinetics. The substitution of methyl group at position three of the decahydroquinoline ring and the presence of electron releasing groups in the aryl group increased the rate of oxidation of the substrates. The change in the rate of oxidation with temperature and solvent composition was also studied. The products formed during the oxidation were also confirmed by using high-performance liquid chromatography (HPLC) and spectral analysis. Key words: 2-aryl-trans-decahydroquinolin-4-ones, kinetics, oxidation, Cetyltrimethylammonium dichromate (CTADC).
{"title":"Substituent effects of 2-aryl-trans-decahydroquinolin-4- ones in CTADC oxidation: Spectrophotometric approach","authors":"N. Sharmila, R. Rao, B. B. Hari, G. Trimurtulu, P. Satyanarayana","doi":"10.5897/AJPAC2014.0555","DOIUrl":"https://doi.org/10.5897/AJPAC2014.0555","url":null,"abstract":"A kinetic study was carried out using spectrophotometric approach on the oxidation of nine differently substituted 2-aryl-trans-decahydroquinolin-4-ones by Cetyltrimethylammonium dichromate (CTADC) as oxidant at 30°C and in aqueous acetic acid (50%) containing catalytic amount of sulphuric acid (6N). The reactions were studied at 350 nm. The reaction was found to follow second order kinetics. The substitution of methyl group at position three of the decahydroquinoline ring and the presence of electron releasing groups in the aryl group increased the rate of oxidation of the substrates. The change in the rate of oxidation with temperature and solvent composition was also studied. The products formed during the oxidation were also confirmed by using high-performance liquid chromatography (HPLC) and spectral analysis. \u0000 \u0000 \u0000 \u0000 Key words: 2-aryl-trans-decahydroquinolin-4-ones, kinetics, oxidation, Cetyltrimethylammonium dichromate (CTADC).","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"40 1","pages":"53-59"},"PeriodicalIF":0.0,"publicationDate":"2014-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77956376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tadjou Do Rego, Serge Fredys, Rodrigue O. Senou, F. Dimon, S. Kpoviessi, Alban G. Houngbèmè, C. A. Eni, G. Accrombessi, F. Gbaguidi
Laboratoire National de Pharmacognosie, Centre Beninois de la Recherche Scientifique et Technique (CBRST), BP 06 Oganla, Porto-Novo, Benin. Laboratory of Physic and Synthesis Organic Chemistry (LaCOPS), University of Abomey-Calavi, Faculty of Sciences and Technics (FAST),BP: 4521 Cotonou, Benin. Laboratory of Physical Chemistry, University of Abomey-Calavi (UAC), Faculty of Sciences and Technics (FAST), Cotonou, Benin. Louvain Drug Research Institute (LDRI), School of Pharmacy, Université catholique de Louvain, B1 7203 Avenue Emmanuel Mounier 72, B-1200 Brussels, Belgium.
{"title":"Adsorption kinetics of 2-chloroacétophénone and 4- bromoacétophénone thiosemicarbazone on Oueme Valley clays (R. Benin)","authors":"Tadjou Do Rego, Serge Fredys, Rodrigue O. Senou, F. Dimon, S. Kpoviessi, Alban G. Houngbèmè, C. A. Eni, G. Accrombessi, F. Gbaguidi","doi":"10.5897/AJPAC2014.0537","DOIUrl":"https://doi.org/10.5897/AJPAC2014.0537","url":null,"abstract":"Laboratoire National de Pharmacognosie, Centre Beninois de la Recherche Scientifique et Technique (CBRST), BP 06 Oganla, Porto-Novo, Benin. Laboratory of Physic and Synthesis Organic Chemistry (LaCOPS), University of Abomey-Calavi, Faculty of Sciences and Technics (FAST),BP: 4521 Cotonou, Benin. Laboratory of Physical Chemistry, University of Abomey-Calavi (UAC), Faculty of Sciences and Technics (FAST), Cotonou, Benin. Louvain Drug Research Institute (LDRI), School of Pharmacy, Université catholique de Louvain, B1 7203 Avenue Emmanuel Mounier 72, B-1200 Brussels, Belgium.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"5 1","pages":"47-52"},"PeriodicalIF":0.0,"publicationDate":"2014-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87867232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The composition of urea treated rice milling waste and its application as animal feed was studied. The proximate analysis of the urea treated rice milling waste showed that it contained 94.90% dry matter, 10.38% crude protein, 5.89% crude fibre, 0.16% ether extract, 7.47% ash, and 54.81% nitrogen-free extracts. The untreated rice milling waste contained 94.34% dry matter, 9.11% crude protein, 6.37% crude fibre, 0.18% ether extract, 8.11% ash, and 54.69% nitrogen-free extracts. Four experimental diets were prepared containing two different levels (30 and 35%) each of untreated and urea treated rice milling waste mixed with commercial pelletized chick mash to assess their effects on weaner rabbits. Data on the feed intake, growth rate, and feed conversion ratio (FCR) of weaner rabbits fed diets containing two different levels each of untreated and urea treated rice milling waste were compared using two-way analysis of variance (ANOVA). There were no significant effects (P > 0.05) of dietary treatment and level of inclusion for average feed intake, average body weight gain, and the FCR. The study indicated that rabbits can be successfully raised on a commercial chick mash mixed with 35% rice milling waste treated or untreated without any adverse effect on growth.
{"title":"Studies on urea treated rice milling waste and its application as animal feed","authors":"Terver Ubwa Simon, Abah James, Atsinafe Oshido Barnabas, Otokpa Esther","doi":"10.5897/AJPAC2013.0532","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0532","url":null,"abstract":"The composition of urea treated rice milling waste and its application as animal feed was studied. The proximate analysis of the urea treated rice milling waste showed that it contained 94.90% dry matter, 10.38% crude protein, 5.89% crude fibre, 0.16% ether extract, 7.47% ash, and 54.81% nitrogen-free extracts. The untreated rice milling waste contained 94.34% dry matter, 9.11% crude protein, 6.37% crude fibre, 0.18% ether extract, 8.11% ash, and 54.69% nitrogen-free extracts. Four experimental diets were prepared containing two different levels (30 and 35%) each of untreated and urea treated rice milling waste mixed with commercial pelletized chick mash to assess their effects on weaner rabbits. Data on the feed intake, growth rate, and feed conversion ratio (FCR) of weaner rabbits fed diets containing two different levels each of untreated and urea treated rice milling waste were compared using two-way analysis of variance (ANOVA). There were no significant effects (P > 0.05) of dietary treatment and level of inclusion for average feed intake, average body weight gain, and the FCR. The study indicated that rabbits can be successfully raised on a commercial chick mash mixed with 35% rice milling waste treated or untreated without any adverse effect on growth.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"1 1","pages":"23-31"},"PeriodicalIF":0.0,"publicationDate":"2014-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90267604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Danish Faizan, M. Zuber S., K. Mehta B., Mehta Darshina, R. Kolisetty S.
Artabotrys odoratissimus has been investigated by many workers for its constituents. The compounds so far isolated from the leaves of A. odoratissimus are Pentadecyl-7-hydroxy- dodecanote, Pentadecyltritriacontanonte, 4,5-epoxy -26-ol- dopentacontane, β-Sitosterol, Aplysterol, Nonacosanylhexaconsanoate, Pentatetraacont-19-ol, triacont-2-ol, Dotriacont-7-ene, Octacose-7-ene, 1-hydroxy-2,5-dimethyl-9,10-anthraquinone, 1,4,5-trihydroxy-9,10-anthraquinone, 13-hydroxynonacosane, Nonanoicacid, Methylphenyl propanoate, Decanoicacid, Diethylphthalate, Dibutylphthalate, 2-amino-3-ethylbipheny-l, 5-methyl-9-phenylnonane-3-ol, 1-phenylundecane, 2,5-dimethyl-1-phenylheptane1-one, hexadeca-2,7,11-triene, 1-isopropyl-4,6-dimethylnaphthalene, 1-phenyldeca-1-one, 1-phenylundecan-1-one, 5-(2-butylphenyl)pent-3-en-2-ol, 2,5-dimethyltetradecanhydro phenenthrene So far, not many studies have been carried out on this genus but there are some reports on this plant. Previous phytochemical studies have revealed this genus to be rich in secondary metabolites including phenylcoumarins, xanthones and triterpenoids. Our recent study on the benzene:acetone extract of the leaves of A. odoratissimus, have led to the isolation of steroidal compound. The structure of the compound has been established by modern spectroscopic techniques such as Infrared Spectrometry (IR), Hydrogen-Nuclear Magnetic Resonance Spectrometry (1H-NMR), Carbon-Nuclear Magnetic Resonance Spectrometry (13C-NMR) and Mass-Spectroscopy and identified as 2β- hydroxy- Stigmasta- 4- en-3, 6- dione- Methoxy ester. Key words: Artabotrys odoratissimus, medicinal plant, new compound, spectral analysis.
{"title":"Phytochemical study on the benzene:acetone extract of the leaves of Artabotrys odoratissimus","authors":"Danish Faizan, M. Zuber S., K. Mehta B., Mehta Darshina, R. Kolisetty S.","doi":"10.5897/AJPAC2013.0536","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0536","url":null,"abstract":"Artabotrys odoratissimus has been investigated by many workers for its constituents. The compounds so far isolated from the leaves of A. odoratissimus are Pentadecyl-7-hydroxy- dodecanote, Pentadecyltritriacontanonte, 4,5-epoxy -26-ol- dopentacontane, β-Sitosterol, Aplysterol, Nonacosanylhexaconsanoate, Pentatetraacont-19-ol, triacont-2-ol, Dotriacont-7-ene, Octacose-7-ene, 1-hydroxy-2,5-dimethyl-9,10-anthraquinone, 1,4,5-trihydroxy-9,10-anthraquinone, 13-hydroxynonacosane, Nonanoicacid, Methylphenyl propanoate, Decanoicacid, Diethylphthalate, Dibutylphthalate, 2-amino-3-ethylbipheny-l, 5-methyl-9-phenylnonane-3-ol, 1-phenylundecane, 2,5-dimethyl-1-phenylheptane1-one, hexadeca-2,7,11-triene, 1-isopropyl-4,6-dimethylnaphthalene, 1-phenyldeca-1-one, 1-phenylundecan-1-one, 5-(2-butylphenyl)pent-3-en-2-ol, 2,5-dimethyltetradecanhydro phenenthrene So far, not many studies have been carried out on this genus but there are some reports on this plant. Previous phytochemical studies have revealed this genus to be rich in secondary metabolites including phenylcoumarins, xanthones and triterpenoids. Our recent study on the benzene:acetone extract of the leaves of A. odoratissimus, have led to the isolation of steroidal compound. The structure of the compound has been established by modern spectroscopic techniques such as Infrared Spectrometry (IR), Hydrogen-Nuclear Magnetic Resonance Spectrometry (1H-NMR), Carbon-Nuclear Magnetic Resonance Spectrometry (13C-NMR) and Mass-Spectroscopy and identified as 2β- hydroxy- Stigmasta- 4- en-3, 6- dione- Methoxy ester. \u0000 \u0000 Key words: Artabotrys odoratissimus, medicinal plant, new compound, spectral analysis.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"76 1","pages":"32-36"},"PeriodicalIF":0.0,"publicationDate":"2014-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79710366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The corrosion and inhibition behaviours of mild steel in sulphuric acid in the presence of Albizia zygia gum (AZ) have been studied using the weight loss, gasometric, Fourier transform infrared (FTIR) and thermometric techniques. The temperature studies reflect that the percentage of inhibition efficiency is decreased with rise in temperature and that indicates the mechanism of physical adsorption. The calculated values of activation energy (Ea) also support the physisorption process. The thermodynamic parameters such as heat of adsorption (Qads) and free energy of adsorption (ΔGads) are suggested that the adsorption of inhibitor on the mild steel surface is exothermic and followed by spontaneous process. The adsorption of the inhibitor on mild steel surface involves the formation of multimolecular layer through C-H bending vibrations due to alkenes at 703.08 and 933.58.01 cm-1, C-O stretches due to carboxylic acid, ester, ether and alcohol at 1084.03 and 1150.58 cm-1, C-O stretch due to ketone /aldehyde/carboxylic acid at 1826.65 cm-1, C-H aliphatic stretch at 2820.99 cm-1 and C-H stretch at 3026.41.79 cm-1, which support physical adsorption. The observed results indicate that A. zygia gum could serve as an effective inhibitor on mild steel in sulphuric acid. Key words: Albizia zygia gum, thermodynamics, mild steel, sulphuric acid, adsorption.
{"title":"Inhibitory action of Albizia zygia gum on mild steel corrosion in acid medium","authors":"P. Ameh","doi":"10.5897/AJPAC2014.0549","DOIUrl":"https://doi.org/10.5897/AJPAC2014.0549","url":null,"abstract":"The corrosion and inhibition behaviours of mild steel in sulphuric acid in the presence of Albizia zygia gum (AZ) have been studied using the weight loss, gasometric, Fourier transform infrared (FTIR) and thermometric techniques. The temperature studies reflect that the percentage of inhibition efficiency is decreased with rise in temperature and that indicates the mechanism of physical adsorption. The calculated values of activation energy (Ea) also support the physisorption process. The thermodynamic parameters such as heat of adsorption (Qads) and free energy of adsorption (ΔGads) are suggested that the adsorption of inhibitor on the mild steel surface is exothermic and followed by spontaneous process. The adsorption of the inhibitor on mild steel surface involves the formation of multimolecular layer through C-H bending vibrations due to alkenes at 703.08 and 933.58.01 cm-1, C-O stretches due to carboxylic acid, ester, ether and alcohol at 1084.03 and 1150.58 cm-1, C-O stretch due to ketone /aldehyde/carboxylic acid at 1826.65 cm-1, C-H aliphatic stretch at 2820.99 cm-1 and C-H stretch at 3026.41.79 cm-1, which support physical adsorption. The observed results indicate that A. zygia gum could serve as an effective inhibitor on mild steel in sulphuric acid. \u0000 \u0000 Key words: Albizia zygia gum, thermodynamics, mild steel, sulphuric acid, adsorption.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"36 1","pages":"37-46"},"PeriodicalIF":0.0,"publicationDate":"2014-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90592873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A simple, highly sensitive, accurate and selective method for determination of trace amounts of Cd(II) in water samples is presented. A novel chemically converted graphene sheets (CCG) solid-phase extraction adsorbent was synthesized by CCG sheets. The stability of a CCG especially in concentrated hydrochloric acid was studied which used as a recycling and preconcentration reagent for further uses of CCG. The method is based on CCG of Cd(II) on surfactant-coated C18, modified with a CCG. The retained ions were then eluted with 4 ml of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 nm for Cd. The influence of flow rates of sample and eluent solutions, pH, breakthrough volume, effect of foreign ions on chelation and recovery were investigated. 1.5 g of surfactant-coated C18 adsorbs 40 mg of the Schiff’s base which in turn can retain 15.2 ± 0.8 mg of each of the two ions. The limit of detection (3σ) for Cd(II) was found to be 3.20 ng L-1. The enrichment factors for both ions are 100. The mentioned method was successfully applied on determination of Cd in different water samples. The ions were also speciated by means of three-column system. Key words: Determination of Cd, preconcentration, chemically converted graphene sheets (CCG), flame atomic absorption spectrometry (FAAS).
提出了一种简便、灵敏、准确、选择性高的测定水样中痕量Cd(II)的方法。以石墨烯片为原料合成了一种新型化学转化石墨烯片固相萃取吸附剂。研究了CCG在浓盐酸中的稳定性，并将其作为回收和预富集试剂，为CCG的进一步利用做准备。该方法是将Cd(II)涂覆在表面活性剂C18上，并用CCG进行修饰。用4 ml 4 M硝酸洗脱残留离子，用火焰原子吸收光谱法(FAAS)在283.3 nm处测定Cd。考察样品流速、洗脱液流速、pH、突破体积、外源离子对螯合和回收率的影响。1.5 g表面活性剂包覆的C18吸附40毫克的希夫碱，而希夫碱又能保留两种离子各15.2±0.8毫克。Cd(II)的检出限(3σ)为3.20 ng L-1。两种离子的富集因子均为100。该方法成功地应用于不同水样中镉的测定。用三柱体系对离子进行了表征。关键词:镉的测定，预富集，化学转化石墨烯片，火焰原子吸收光谱法
{"title":"Preconcentration of Cd(II) by chemically converted graphene sheets adsorbed on surfactant- coated C18 before determination by flame atomic absorption spectrometry (FAAS)","authors":"A. Moghimi, M. Farahmandjou","doi":"10.5897/AJPAC2013.0542","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0542","url":null,"abstract":"A simple, highly sensitive, accurate and selective method for determination of trace amounts of Cd(II) in water samples is presented. A novel chemically converted graphene sheets (CCG) solid-phase extraction adsorbent was synthesized by CCG sheets. The stability of a CCG especially in concentrated hydrochloric acid was studied which used as a recycling and preconcentration reagent for further uses of CCG. The method is based on CCG of Cd(II) on surfactant-coated C18, modified with a CCG. The retained ions were then eluted with 4 ml of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 nm for Cd. The influence of flow rates of sample and eluent solutions, pH, breakthrough volume, effect of foreign ions on chelation and recovery were investigated. 1.5 g of surfactant-coated C18 adsorbs 40 mg of the Schiff’s base which in turn can retain 15.2 ± 0.8 mg of each of the two ions. The limit of detection (3σ) for Cd(II) was found to be 3.20 ng L-1. The enrichment factors for both ions are 100. The mentioned method was successfully applied on determination of Cd in different water samples. The ions were also speciated by means of three-column system. Key words: Determination of Cd, preconcentration, chemically converted graphene sheets (CCG), flame atomic absorption spectrometry (FAAS).","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"20 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2014-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79196289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The corrosion inhibition of mild steel in H2SO4 solution in the presence of Juniperus plant at a temperature range of 30 to 60°C was studied using chemical (HE and WL) and electrochemical (PDP and EIS) methods. The Juniperus plant acts as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration but decreases with an increase in temperature. The inhibitive effect of the Juniperus plant could be attributed to the presence of some compound in the plant which is adsorbed on the surface of the mild steel. The Juniperus plant was found to conform to the Frumkin adsorption isotherm and Temkin adsorption isotherm at all the concentration levels and temperature studied. The phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters revealed that the adsorption process is spontaneous. Key words: Corrosion-inhibition, frumkin adsorption isotherm and temkin adsorption isotherm, physical adsorption, Juniperus plant.
{"title":"Inhibition of mild steel corrosion using Juniperus plants as green inhibitior","authors":"S. Al-Mhyawi","doi":"10.5897/AJPAC2013.0497","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0497","url":null,"abstract":"The corrosion inhibition of mild steel in H2SO4 solution in the presence of Juniperus plant at a temperature range of 30 to 60°C was studied using chemical (HE and WL) and electrochemical (PDP and EIS) methods. The Juniperus plant acts as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration but decreases with an increase in temperature. The inhibitive effect of the Juniperus plant could be attributed to the presence of some compound in the plant which is adsorbed on the surface of the mild steel. The Juniperus plant was found to conform to the Frumkin adsorption isotherm and Temkin adsorption isotherm at all the concentration levels and temperature studied. The phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters revealed that the adsorption process is spontaneous. \u0000 \u0000 Key words: Corrosion-inhibition, frumkin adsorption isotherm and temkin adsorption isotherm, physical adsorption, Juniperus plant.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"92 1","pages":"9-22"},"PeriodicalIF":0.0,"publicationDate":"2014-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80314927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The micro morphology of limestone sorbent is a key for improving the SO2 removal efficiency in the coal-fired power plant. The tube furnace system was built for imitating the indirect desulfurization reaction in traditional boiler atmosphere (65%N2, 15%CO2, 4.7%O2, 15%H2O, 0.3%SO2) and the direct desulfurization reaction in oxygen-fired atmosphere (80%CO2, 4.7%O2, 15%H2O, 0.3%SO2). The reacted limestone particle samples were observed by SEM and are analyzed by Fourier transformation 3-D reconstruction technique. It is shown that the sizes of internal pore within sorbent particle in two kind atmospheres differ by an order of magnitude, one is about 200 nm for indirect desulfurization, and the other is about 20 nm for direct desulfurization. The CaSO4 products of indirect desulfurization are chaotic derivatives with serious blockage, and the direct desulfurization product layer belongs to uniform honeycombed micro-structure without blockage. Those numerous micro-porous passages can guarantee continuous reactive substance transmission. Key words: Limestone powder, SO2 removal, particle surface, 3-D reconstruction, product layer.
{"title":"Microstructure contradistinction for indirect/direct desulfurization product layer of limestone particle in coal-fired flue gas","authors":"Jianyu Shang, Zhongliang Liu, Chunbo Wang","doi":"10.5897/AJPAC2013.0523","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0523","url":null,"abstract":"The micro morphology of limestone sorbent is a key for improving the SO2 removal efficiency in the coal-fired power plant. The tube furnace system was built for imitating the indirect desulfurization reaction in traditional boiler atmosphere (65%N2, 15%CO2, 4.7%O2, 15%H2O, 0.3%SO2) and the direct desulfurization reaction in oxygen-fired atmosphere (80%CO2, 4.7%O2, 15%H2O, 0.3%SO2). The reacted limestone particle samples were observed by SEM and are analyzed by Fourier transformation 3-D reconstruction technique. It is shown that the sizes of internal pore within sorbent particle in two kind atmospheres differ by an order of magnitude, one is about 200 nm for indirect desulfurization, and the other is about 20 nm for direct desulfurization. The CaSO4 products of indirect desulfurization are chaotic derivatives with serious blockage, and the direct desulfurization product layer belongs to uniform honeycombed micro-structure without blockage. Those numerous micro-porous passages can guarantee continuous reactive substance transmission. \u0000 \u0000 Key words: Limestone powder, SO2 removal, particle surface, 3-D reconstruction, product layer.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"29 1","pages":"370-374"},"PeriodicalIF":0.0,"publicationDate":"2013-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76318260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The seeds of Momordica charantia were extracted with hexane, ethyl acetate and 95% ethanol successively by percolation and concentrated at 37°C. Fractions 19-21 and 247 gave two compounds. However, only one has been elucidated to be 4a-phorbol-12, 13-didecanoate using the state- of –art- tools of spectrometry. The phytochemical screening of seeds of M. charantia showed the presence of flavonoids, glycosides, sterols, fat and oil in hexane, ethyl acetate and ethanol extracts. Anthraquinone is only present in hexane and ethyl acetate while alkaloid is in hexane and ethanol. And also phyto-medicine should be integrated into the health system of Nigeria and developed in such a way to bring harmony between the traditional and modern system of health care with minimum threat to each other. Key words: Momordica charantia, Cucurbitaceae, gas chromatography, thin layer chromatography, phytochemicals.
{"title":"Didecanoate compound: Isolated from Momordica charantia Linn. seeds from Nigeria","authors":"N. Leonard, O. Olutayo, O. Otu, K. Simon","doi":"10.5897/AJPAC2013.0528","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0528","url":null,"abstract":"The seeds of Momordica charantia were extracted with hexane, ethyl acetate and 95% ethanol successively by percolation and concentrated at 37°C. Fractions 19-21 and 247 gave two compounds. However, only one has been elucidated to be 4a-phorbol-12, 13-didecanoate using the state- of –art- tools of spectrometry. The phytochemical screening of seeds of M. charantia showed the presence of flavonoids, glycosides, sterols, fat and oil in hexane, ethyl acetate and ethanol extracts. Anthraquinone is only present in hexane and ethyl acetate while alkaloid is in hexane and ethanol. And also phyto-medicine should be integrated into the health system of Nigeria and developed in such a way to bring harmony between the traditional and modern system of health care with minimum threat to each other. \u0000 \u0000 Key words: Momordica charantia, Cucurbitaceae, gas chromatography, thin layer chromatography, phytochemicals.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"12 1","pages":"375-381"},"PeriodicalIF":0.0,"publicationDate":"2013-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81923159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pigment is one of the main components in paint formulation which is dominated with the use of titanium dioxide, due primarily to three important physical characteristics; which are high refractive index, high opacity and chemical inertness. However, due to increasing demand of this important pigment and the attendant increase in price, it has become imperative to develop cheaper alternative source with similar properties. One such alternative is calcined kaolin. Knowing fully that not all kaolin deposits can be calcined to meet the peculiar requirements, this paper therefore highlights the potentials of some Nigeria kaolin deposits that can be calcined and utilized as alternatives to titanium dioxide in paint formulation. The paper also highlights the other pigments used in the coating industry, their advantages, disadvantages and their national and international market trends. Key words: Pigments, calcined kaolin, titanium dioxide, refractive index, opacity.
{"title":"Potentials of Nigerian calcined kaolin as paint pigment","authors":"F. Alabi, O. Omojola.M.","doi":"10.5897/AJPAC2013.0530","DOIUrl":"https://doi.org/10.5897/AJPAC2013.0530","url":null,"abstract":"Pigment is one of the main components in paint formulation which is dominated with the use of titanium dioxide, due primarily to three important physical characteristics; which are high refractive index, high opacity and chemical inertness. However, due to increasing demand of this important pigment and the attendant increase in price, it has become imperative to develop cheaper alternative source with similar properties. One such alternative is calcined kaolin. Knowing fully that not all kaolin deposits can be calcined to meet the peculiar requirements, this paper therefore highlights the potentials of some Nigeria kaolin deposits that can be calcined and utilized as alternatives to titanium dioxide in paint formulation. The paper also highlights the other pigments used in the coating industry, their advantages, disadvantages and their national and international market trends. \u0000 \u0000 Key words: Pigments, calcined kaolin, titanium dioxide, refractive index, opacity.","PeriodicalId":7556,"journal":{"name":"African Journal of Pure and Applied Chemistry","volume":"1 1","pages":"410-417"},"PeriodicalIF":0.0,"publicationDate":"2013-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85910954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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