Pub Date : 2007-11-19DOI: 10.4314/NJCR.V11I1.35626
F. Islamoglu, B. Kahveci, Y. Islamoğlu
To gain more information about the effect of solvent on 4,5-dihydro-1H-1,2,4-triazol-5-ones, the stoichiometric protonation constants of thirteen triazoles in ethanol-water mixtures were determined at an ionic strength of 0.10 M NaCl and at 25.0 ± 0.1 oC under nitrogen atmosphere. A potentiometric method was used and the calculation was carried out using the PKAS computer program. The corresponding pK a values of these triazoles were determined in ethanol-water mixtures. Thus, the effects of solvent and molecular structure upon acidity were investigated. The logarithm of the protonation constants of the above-mentioned 4,5-dihydro-1H-1,2,4-triazol-5-ones linearly decreased with increases in ethanol contents but the values that determined 80% ethanol did not follow this linear trend. The variation of these constants is discussed on the basis of specific solute-solvent interactions. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 1-10
为了进一步了解溶剂对4,5-二氢- 1h -1,2,4-三唑-5-酮的影响，在离子强度为0.10 M NaCl和25.0±0.1℃的氮气气氛下，测定了13种三唑在乙醇-水混合物中的化学计量质子化常数。采用电位法，利用PKAS计算机程序进行计算。测定了这些三唑在乙醇-水混合物中相应的pK值。因此，研究了溶剂和分子结构对酸度的影响。上述4,5-二氢- 1h -1,2,4-三唑-5-酮的质子化常数的对数随乙醇含量的增加而线性降低，但测定80%乙醇的值不遵循这种线性趋势。根据溶质-溶剂的特定相互作用，讨论了这些常数的变化。尼日利亚化学研究杂志Vol. 11 2006: pp. 1-10
{"title":"Determination of the Protonation Constants of Some 3-Alkyl(Aryl)-4-(Substitutebenzylamino)-4,5-Dihydro-1H-1,2,4-Triazol-5-ones by the Potentiometric Method in Ethanol-Water Mixtures","authors":"F. Islamoglu, B. Kahveci, Y. Islamoğlu","doi":"10.4314/NJCR.V11I1.35626","DOIUrl":"https://doi.org/10.4314/NJCR.V11I1.35626","url":null,"abstract":"To gain more information about the effect of solvent on 4,5-dihydro-1H-1,2,4-triazol-5-ones, the stoichiometric protonation constants of thirteen triazoles in ethanol-water mixtures were determined at an ionic strength of 0.10 M NaCl and at 25.0 ± 0.1 oC under nitrogen atmosphere. A potentiometric method was used and the calculation was carried out using the PKAS computer program. The corresponding pK a values of these triazoles were determined in ethanol-water mixtures. Thus, the effects of solvent and molecular structure upon acidity were investigated. The logarithm of the protonation constants of the above-mentioned 4,5-dihydro-1H-1,2,4-triazol-5-ones linearly decreased with increases in ethanol contents but the values that determined 80% ethanol did not follow this linear trend. The variation of these constants is discussed on the basis of specific solute-solvent interactions. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 1-10","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131042307","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}
Pub Date : 2007-11-19DOI: 10.4314/NJCR.V11I1.35627
M. O. Edema, S. I. Onyeka
Diacyl triazene – N – oxides were synthesized by reaction of p- nitroso, N,N-dimethyl aniline with some acyl hydrazines. The product yield varied from 56% - 80.8%. The conditions for optimum yields and spectral characteristics of the products are reported. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 11-14
以对亚硝基，N,N-二甲基苯胺与一些酰基肼为原料，合成了二酰基三氮- N氧化物。产物收率为56% ~ 80.8%。报道了最佳收率条件和产物的光谱特性。尼日利亚化学研究杂志Vol. 11 2006: pp. 11-14
{"title":"Synthesis of Di -Acyl Triazene – N – Oxide","authors":"M. O. Edema, S. I. Onyeka","doi":"10.4314/NJCR.V11I1.35627","DOIUrl":"https://doi.org/10.4314/NJCR.V11I1.35627","url":null,"abstract":"Diacyl triazene – N – oxides were synthesized by reaction of p- nitroso, N,N-dimethyl aniline with some acyl hydrazines. The product yield varied from 56% - 80.8%. The conditions for optimum yields and spectral characteristics of the products are reported. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 11-14","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133127026","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}
Pub Date : 2007-11-19DOI: 10.4314/NJCR.V11I1.35631
F. Okieimen, I. P. Bakare
One of the important issues in producing composite materials with natural fibres is the modification of the surface of the fibres to enhance adhesion and interfacial bonding with polymer matrix. In this report, the effect of alkalization on the mechanical properties, thermal stability and surface morphology of banana stem fibres is examined. The results show that treatment with sodium hydroxide modified the surface of the fibre, attenuating IR absorption intensities at 1733cm -1 corresponding to reduction of C=O groups, at 1514cm -1 and between 3000 and 2850cm -1 associated with reduction/removal of low molecular weight constituents of the fibres. It was found that alkali-treatment improved both tensile and flexural strengths, and the thermal stability of the fibres. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 36-42
利用天然纤维制备复合材料的一个重要问题是对纤维表面进行改性，以增强其与聚合物基体的附着力和界面键合。本文研究了碱化对香蕉茎纤维的力学性能、热稳定性和表面形貌的影响。结果表明，氢氧化钠修饰了纤维表面，在1733cm -1处的红外吸收强度与C=O基团的还原有关，在1514cm -1和3000 ~ 2850cm -1处的红外吸收强度与纤维低分子量成分的还原/去除有关。结果表明，碱处理提高了纤维的拉伸强度和弯曲强度以及热稳定性。尼日利亚化学研究杂志Vol. 11 2006: pp. 36-42
{"title":"Short communication: Alkaline surface modification of banana stem fibres","authors":"F. Okieimen, I. P. Bakare","doi":"10.4314/NJCR.V11I1.35631","DOIUrl":"https://doi.org/10.4314/NJCR.V11I1.35631","url":null,"abstract":"One of the important issues in producing composite materials with natural fibres is the modification of the surface of the fibres to enhance adhesion and interfacial bonding with polymer matrix. In this report, the effect of alkalization on the mechanical properties, thermal stability and surface morphology of banana stem fibres is examined. The results show that treatment with sodium hydroxide modified the surface of the fibre, attenuating IR absorption intensities at 1733cm -1 corresponding to reduction of C=O groups, at 1514cm -1 and between 3000 and 2850cm -1 associated with reduction/removal of low molecular weight constituents of the fibres. It was found that alkali-treatment improved both tensile and flexural strengths, and the thermal stability of the fibres. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 36-42","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124920153","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}
Pub Date : 2007-11-19DOI: 10.4314/NJCR.V11I1.35629
F. Okieimen, R. O. Amaye, A. Jideonwo
Graft copolymers of Acrylonitrile and ethyl methcrylate on dextrin were prepared by the use of ceric ion initiator in aqueous medium at 290C. The molecular weight of grafted poly(ethyl methacrylate) chains were higher than for polyacrylonitrile grafts; but the latter were more frequently grafted on the backbone polymer. The dependence of the molecular weight of the grafted chains on ceric ion concentration suggests that interaction of growing graft polymer chains with ceric ion is important in the termination process of graft copolymerisation. Graft copolymeriation of ethyl methacrylate onto dextrin in the presence of various amounts of acrylonitrile was studied. The compositions of the copolymer samples, calculated from their nitrogen content, showed that in the presence of ethyl acrylate, relatively small amounts of acrylonitrile monomer was grafted onto dextrin. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 22-27
用铈离子引发剂在290C水介质中制备了丙烯腈和甲基丙烯酸乙酯在糊精上的接枝共聚物。接枝的聚甲基丙烯酸乙酯链分子量高于接枝的聚丙烯腈链;而后者则更多地接枝在骨架聚合物上。接枝聚合物链分子量对铈离子浓度的依赖性表明，接枝聚合物链与铈离子的相互作用在接枝共聚终止过程中起重要作用。研究了在不同量丙烯腈存在下甲基丙烯酸乙酯与糊精的接枝共聚反应。共聚物样品的组成，从它们的氮含量计算，表明在丙烯酸乙酯存在下，相对少量的丙烯腈单体接枝到糊精上。尼日利亚化学研究杂志Vol. 11 2006: pp. 22-27
{"title":"Graft Copolymerization of Acrylonitrile and Ethyl Methacrylate on Dextrin","authors":"F. Okieimen, R. O. Amaye, A. Jideonwo","doi":"10.4314/NJCR.V11I1.35629","DOIUrl":"https://doi.org/10.4314/NJCR.V11I1.35629","url":null,"abstract":"Graft copolymers of Acrylonitrile and ethyl methcrylate on dextrin were prepared by the use of ceric ion initiator in aqueous medium at 290C. The molecular weight of grafted poly(ethyl methacrylate) chains were higher than for polyacrylonitrile grafts; but the latter were more frequently grafted on the backbone polymer. The dependence of the molecular weight of the grafted chains on ceric ion concentration suggests that interaction of growing graft polymer chains with ceric ion is important in the termination process of graft copolymerisation. Graft copolymeriation of ethyl methacrylate onto dextrin in the presence of various amounts of acrylonitrile was studied. The compositions of the copolymer samples, calculated from their nitrogen content, showed that in the presence of ethyl acrylate, relatively small amounts of acrylonitrile monomer was grafted onto dextrin. Nigerian Journal of Chemical Research Vol. 11 2006: pp. 22-27","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127942232","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 kinetics of the reduction of [Co(Ox) 3 ] 3- with catechol has been studied in aqueous acid (HClO 4 ) medium at I = 1.00moldm -3 (NaClO 4 ) and T=26.3±0.1°C. Two moles of oxidant were consumed by one mole of reductant. The reaction is second order overall, first order in both oxidant and reductant and shows a first order direct acid dependence. Polymerisation test suggested the presence of free radicals as intermediates in the reaction. The kinetic data are consistent with the following equation: -d/2dt[Co(Ox) 3 3- ] = k 2 [Co(Ox) 3 3- ][H 2 Q]. Where k 2 = k a [H + ]. The experimental results are in favour of the outer-sphere mechanism. Nigerian Journal of Chemical Research Vol. 9, 2004: 35-39
{"title":"Kinetics and mechanism of the redox reaction between catechol and trisoxalatocobaltate (III) ion in aqueous acid medium","authors":"S. Mamman, J. Iyun","doi":"10.4314/NJCR.V9I1.35566","DOIUrl":"https://doi.org/10.4314/NJCR.V9I1.35566","url":null,"abstract":"The kinetics of the reduction of [Co(Ox) 3 ] 3- with catechol has been studied in aqueous acid (HClO 4 ) medium at I = 1.00moldm -3 (NaClO 4 ) and T=26.3±0.1°C. Two moles of oxidant were consumed by one mole of reductant. The reaction is second order overall, first order in both oxidant and reductant and shows a first order direct acid dependence. Polymerisation test suggested the presence of free radicals as intermediates in the reaction. The kinetic data are consistent with the following equation: -d/2dt[Co(Ox) 3 3- ] = k 2 [Co(Ox) 3 3- ][H 2 Q]. Where k 2 = k a [H + ]. The experimental results are in favour of the outer-sphere mechanism. Nigerian Journal of Chemical Research Vol. 9, 2004: 35-39","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125326816","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}
Pub Date : 2006-11-08DOI: 10.4314/NJCR.V10I1.35624
M. Turoti
The effects of weathering on poly(glycerol-phthalate) based alkyd coatings of the unstabilised and stabilised samples using varying amounts of dibutyltin distearate have been studied. The weathering and stabilization processes were monitored using infrared spectroscopy,gel formation, colour development, tensile strength as well as determination of time of embrittlement. The results showed that, relative to the control, there were, reduction in hydroxyl moiety formation, lack of discoloration, increased gel content, enhanced tensile strength and elongated life span of the stabilised alkyd coating,This indicated effective reduction in degradation reactions in the presence of the test tin ester The 10 x 10 -4 mole% dibutyltin distearate was the most effective concentration that stabilized the alkyd coatings. Nigerian Journal of Chemical Research Vol. 10, 2005: 30-38
{"title":"The stabilizing effects of dibutyltin distearate on some properties of poly (glycerol-phthalate) based alkyd coating exposed to outdoor weather","authors":"M. Turoti","doi":"10.4314/NJCR.V10I1.35624","DOIUrl":"https://doi.org/10.4314/NJCR.V10I1.35624","url":null,"abstract":"The effects of weathering on poly(glycerol-phthalate) based alkyd coatings of the unstabilised and stabilised samples using varying amounts of dibutyltin distearate have been studied. The weathering and stabilization processes were monitored using infrared spectroscopy,gel formation, colour development, tensile strength as well as determination of time of embrittlement. The results showed that, relative to the control, there were, reduction in hydroxyl moiety formation, lack of discoloration, increased gel content, enhanced tensile strength and elongated life span of the stabilised alkyd coating,This indicated effective reduction in degradation reactions in the presence of the test tin ester The 10 x 10 -4 mole% dibutyltin distearate was the most effective concentration that stabilized the alkyd coatings. Nigerian Journal of Chemical Research Vol. 10, 2005: 30-38","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123419008","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}
Pub Date : 2006-11-08DOI: 10.4314/NJCR.V10I1.35585
I. Dioha, M. Agho, A. Sambo
Various analyses and sensory evaluation of palm wine analogue and oil palm wine have been carried out. Important parameters such as physicochemical properties, nutritive values, phytochemical screening and microbiological analysis of the two brands of wines were assessed. The results show that the wines have similar properties with insignificant variations in their values. Sensory evaluation with t-test showed that there was no significant difference (P=0.05 and P=0.01) in colour, odour, effervescence and general acceptability between palm wine analogue and oil palm wine. While there also was no significant difference in the tastes and balance of sweetness at P=0.01, a slight difference existed at P=0.05. Nigerian Journal of Chemical Research Vol. 10, 2005: 1-7
{"title":"Evaluative comparison of palm wine analogue and oil palm wine","authors":"I. Dioha, M. Agho, A. Sambo","doi":"10.4314/NJCR.V10I1.35585","DOIUrl":"https://doi.org/10.4314/NJCR.V10I1.35585","url":null,"abstract":"Various analyses and sensory evaluation of palm wine analogue and oil palm wine have been carried out. Important parameters such as physicochemical properties, nutritive values, phytochemical screening and microbiological analysis of the two brands of wines were assessed. The results show that the wines have similar properties with insignificant variations in their values. Sensory evaluation with t-test showed that there was no significant difference (P=0.05 and P=0.01) in colour, odour, effervescence and general acceptability between palm wine analogue and oil palm wine. While there also was no significant difference in the tastes and balance of sweetness at P=0.01, a slight difference existed at P=0.05. Nigerian Journal of Chemical Research Vol. 10, 2005: 1-7","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130992909","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}
Pub Date : 2006-11-08DOI: 10.4314/NJCR.V10I1.35622
S. Idris, J. Iyun, E. Agbaji
Kinetic and mechanistic studies of electron transfer reaction of butane-1,3-diol and Cr(VI) ion in aqueous acidic medium have been carried out in aqueous medium at 271°C, I = 1.0 mol dm -3 (NaCl), [H + ] = 0.5mol dm -3 (HCl). The reaction was inhibited by added anions and showed negative salt effect. Spectroscopic investigations confirmed that precursor complex formation did not precede the electron transfer step. Interpretation of these observations suggest that the reactions most likely occur by the outersphere mechanism Nigerian Journal of Chemical Research Vol. 10, 2005: 15-20
{"title":"Electron transfer reaction of butane -1,3-diol and cr(vi) in aqueous acidic medium","authors":"S. Idris, J. Iyun, E. Agbaji","doi":"10.4314/NJCR.V10I1.35622","DOIUrl":"https://doi.org/10.4314/NJCR.V10I1.35622","url":null,"abstract":"Kinetic and mechanistic studies of electron transfer reaction of butane-1,3-diol and Cr(VI) ion in aqueous acidic medium have been carried out in aqueous medium at 271°C, I = 1.0 mol dm -3 (NaCl), [H + ] = 0.5mol dm -3 (HCl). The reaction was inhibited by added anions and showed negative salt effect. Spectroscopic investigations confirmed that precursor complex formation did not precede the electron transfer step. Interpretation of these observations suggest that the reactions most likely occur by the outersphere mechanism Nigerian Journal of Chemical Research Vol. 10, 2005: 15-20","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"75 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116731190","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}
Pub Date : 2006-11-08DOI: 10.4314/NJCR.V10I1.35623
J. Lori, Sz Kazaure, S. Dangoggo
The adsorption of mucin onto HA has been investigated with respect to the role of electrostatic interactions, ionic environment, mucin concentration and pH. Aqueous solution of Mucin was suspended with treated and untreated HA and the mucin concentration in the supernatant determined. The Langmuir's model was used to analyze isotherm data; the maximum amount of mucin adsorbed and the affinity or association constants were calculated. The presence of added Ca ions increased the amount of mucin adsorbed as well as the association constant. Nigerian Journal of Chemical Research Vol. 10, 2005: 21-29
{"title":"Mechanism for the adsorption of mucin on hydroxyapatite","authors":"J. Lori, Sz Kazaure, S. Dangoggo","doi":"10.4314/NJCR.V10I1.35623","DOIUrl":"https://doi.org/10.4314/NJCR.V10I1.35623","url":null,"abstract":"The adsorption of mucin onto HA has been investigated with respect to the role of electrostatic interactions, ionic environment, mucin concentration and pH. Aqueous solution of Mucin was suspended with treated and untreated HA and the mucin concentration in the supernatant determined. The Langmuir's model was used to analyze isotherm data; the maximum amount of mucin adsorbed and the affinity or association constants were calculated. The presence of added Ca ions increased the amount of mucin adsorbed as well as the association constant. Nigerian Journal of Chemical Research Vol. 10, 2005: 21-29","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122078303","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}
Pub Date : 2006-11-08DOI: 10.4314/NJCR.V10I1.35621
S. Idris, J. Iyun, E. Agbaji
INTRODUCTION Oxidative properties of Cr(VI) are of considerable importance in both analysis and oxidation of organic and inorganic substrates . Cr (VI) in water exists as CrO4, HCr2O7 and H2Cr2O7 . Of all these species, HCrO4 has been identified as the only active oxidizing species in aqueous acidic solution . Although some kinetic information has been published on the oxidation of secondary alcohol by Cr(VI) 1,2, 8-16 complementary studies on its possible reaction pathways are scanty. It is in the light of this that the present work was undertaken with the aim of providing relevant information on the plausible mechanism for the electron transfer reaction of 2-methylpentane-2,4-diol . EXPERIMENTAL Materials 2-methylpentane-2,4-diol (BDH) hereafter referred to as diol was used as supplied in making its standard solution. Sodium dichromate solution in distilled water was then standardized using titrimetric method. A stock solution of HCl was prepared by diluting the commercial acid (M&B) and the solution was standardized titrimetrically using sodium carbonate. Stock solutions of sodium methanoate, sodium chloride and sodium ethanoate were prepared from Analar grade salts. The stoichiometry and kinetics of the reduction of dichromate ion by 2-methylpentane-2,4-diol have been investigated in aqueous hydrochloric acid medium at 27 ±1°C. The reaction is first order with respect to oxidant and reductant concentrations and also acid dependent. The empirical rate law conforms to the rate equation: )] ( ][ tan ][ [ ] [
{"title":"Kinetics and mechanism of the reduction of dichromate ion by 2-methyl pentane-2,4-diol in aqueous hydrochloric acidic medium","authors":"S. Idris, J. Iyun, E. Agbaji","doi":"10.4314/NJCR.V10I1.35621","DOIUrl":"https://doi.org/10.4314/NJCR.V10I1.35621","url":null,"abstract":"INTRODUCTION Oxidative properties of Cr(VI) are of considerable importance in both analysis and oxidation of organic and inorganic substrates . Cr (VI) in water exists as CrO4, HCr2O7 and H2Cr2O7 . Of all these species, HCrO4 has been identified as the only active oxidizing species in aqueous acidic solution . Although some kinetic information has been published on the oxidation of secondary alcohol by Cr(VI) 1,2, 8-16 complementary studies on its possible reaction pathways are scanty. It is in the light of this that the present work was undertaken with the aim of providing relevant information on the plausible mechanism for the electron transfer reaction of 2-methylpentane-2,4-diol . EXPERIMENTAL Materials 2-methylpentane-2,4-diol (BDH) hereafter referred to as diol was used as supplied in making its standard solution. Sodium dichromate solution in distilled water was then standardized using titrimetric method. A stock solution of HCl was prepared by diluting the commercial acid (M&B) and the solution was standardized titrimetrically using sodium carbonate. Stock solutions of sodium methanoate, sodium chloride and sodium ethanoate were prepared from Analar grade salts. The stoichiometry and kinetics of the reduction of dichromate ion by 2-methylpentane-2,4-diol have been investigated in aqueous hydrochloric acid medium at 27 ±1°C. The reaction is first order with respect to oxidant and reductant concentrations and also acid dependent. The empirical rate law conforms to the rate equation: )] ( ][ tan ][ [ ] [","PeriodicalId":102130,"journal":{"name":"Nigerian Journal of Chemical Research","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125200867","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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