In the present work cyclic voltammetric and electron spin resonance (ESR) spectroscopic investigations of fifteen quinones have been carried out. Quinones belong to a class of organic compounds, which find potential applications in biology and chemistry. Five compounds from each of the three series of quinones, namely benzoquinones (BQs), naphthoquinones (NQs) and anthraquinones (AQs), were selected for the present study. Systematic cyclic voltammetric measurements were made on all compounds in solvents dichloromethane (DCM), acetonitrile (AN) and propylene carbonate (PC) at 25 o C. Analysis of the voltammograms provided fundamental electrochemical parameters (redox potentials, peak separation, peak currents, half-wave potential, peak width) which helped in the interpretation of role of solvents, role of structure and the effect of substituents. The redox behaviour of the compounds was examined first within a series and then a comparative analysis of the three series was made. It was found that substituents affect strongly the redox bahaviour of the compounds. The quinones with electron withdrawing groups were easily reduced than those with electron releasing groups. Among the three series the ease of reduction followed the order BQs>NQs>AQs. 2-Hydroxy-1, 4-naphthoquinone behaved differently due to self protonation. The heterogeneous electron transfer rate constants (k o ) of the first and the second reduction steps were determined in the three solvents employing Nicholson and Kochi methods. The experimental results were compared with those calculated theoretically from the modified form of the Marcus theory. The solvent reorganization energy (λ o ) in the Marcus equation was calculated using the conventional spherical as well as multisphere models. Experimental rate constants in acetonitrile from the Kochi’s method for benzoquinones, naphthoquinones and anthraquinones were found in the range 1.65 x 10 -3 – 8.47 x 10 -3 cm s -1 , 7.09 x 10 -3 – 11.16 x 10 -3 cm s -1 , and 0.19 x 10 -3 – 7.10 x 10 -3 cm s -1 respectively. The experimentally determined rate constants for quinones were found in close agreement with the theoretically calculated rate constants from the Kochi’s method. The effect of medium on electron transfer rates was rationalized in terms of solvent properties such as polarity, viscosity, density relaxation time. An increase in the solvent polarity and a decrease in viscosity favoured the heterogeneous iiielectron transfer rate. Electron transfer rates were found inversely proportional to solvent longitudinal relaxation time. Electrochemical behaviour of quinones was also investigated in the presence of tert-butanol, 2-propanol, ethanol and methanol (monoalcohols), ethylene glycol (a diol) and glycerol (a triol) as proton donors. The quinone-alcohol interaction was analyzed from changes observed in the shape and peak position of the redox waves in voltammograms as a result of change in concentration of the added alcohol. An estimate of the strength of the quinone-alcohol interaction which is hydrogen bonding in nature was obtained by calculating the thermodynamic association constants and the number of alcohol molecules attached to anion or dianion of quinones. The interaction with dianion was found much stronger than with the anion. The strength of the hydrogen bond depended upon the basicity of the quinone and acidity of the alcohol. The presence of α- hydrogens in the quinone structure strengthened the interaction. A comparison of the results for monoalcohols, diol and triol shows that the polyalcohols formed stronger hydrogen bonds. The strength of interaction increased with the increase in the number of OH groups. Homogeneous electron transfer rate constants of quinones in acetonitrile were determined from ESR spectroscopic measurements at 298K. The anion radical of the quinone was generated in situ in a locally fabricated esr-electrochemical cell and the hyperfine spectrum recorded. The hyperfine coupling constants and the line widths were determined from the experimental and simulated ESR spectra. The electron self exchange rate constant was determined from the concentration depended chemical line broadening produced by the addition of neutral quinone. The rate constants were found in the range of 5.2 x 10 8 - 4.4 x 10 9 M -1 s -1 . The strength of precursor complex is observed in terms of association constants (K A ) calculated from the experimental electron transfer rate constants are in the range 0.028 – 1.023 M -1 . Theoretical values of K A were calculated using Eigen-Fuoss and reaction zone models. The values calculated with the reaction zone model agreed with the experimentally determined values. The ESR results support the observed trends in electrochemical behaviour of quinones.
This study examines the concept of globalisation in its characteristics ramifications. The research used empiricism or an empirical method of data collection and analysis. The research used feasibility and affordability in gathering of data for the work using empirical approach in which statistics and figures from credible sources are relied on. The data obtained were discussed using empirical methodological analysis where some themes are identified and discussed from the topic of the study using scientific tools such as tables, charts, bars and figures where necessary. The research discovered that globalisation is not a good phenomenon in African continent owing to slow economic growth, trade disequilibrium and parallel development comparatively because of disadvantages in terms of export, volume of trade exchange and low level of technological development. The research recommends that there is an urgent need for the African countries to restrategise and reshape their economic and political interest at the global level through the creation of a competitive means of relevance at the global centre-stage of world economy and politics.
Pakistan’s energy and power sector underperformed over the decades for its failure to adequately plan, formulate and implement the policies. As a result, the country which is believed to have abundant energy resources is coping significant electricity shortfall since 2006. This situation is confronting governments for many years to address these crises. However, in the absence of effective energy planning, various conformist planning and policy initiative could not deliver and decrease the reliance on imported fuels for power generation. The imported fossil fuels are huge burden for the national exchequer, on one hand, and are also unsustainable as they adversely add to climate change on the other hand. These circumstances warrant an energy security concern since the obscure future with growing population and economy pose a serious challenge to meet unprecedented electricity demand. It is, therefore, inevitable that Pakistan undertakes sustainable energy planning thereby acknowledging indigenous renewable energy resources and focusing energy efficiency and conservation. This research develops an energy modeling and decision support framework for the judicious energy policy development by incorporating sustainability criteria for the sustainable electricity system of Pakistan. This planning framework addresses two key shortcomings of unaided energy modeling for energy planning. First, the models typically provide a set of scenario alternatives which are based on the modeling parameters and not on the sustainability criteria as well as without appropriate decision support, and secondly, the energy policy makers in the developing countries little understand the inherent complexities of the energy models. As such, in this study following energy modeling, using Long-range Energy Alternatives Planning System (LEAP), sustainability assessment of modeling results is undertaken using Expert Choice Comparion® decision tool. The Expert Choice Comparion® decision tool is based on the Analytical Hierarchy Process (AHP) methodology of Multi-Criteria Decision Making (MCDM) methods. This research covers the study period of 2015-2050. Pakistan’s LEAP model results for the electricity demand forecast 1706.1 TWh of electricity requirements in 2050 which is 19 folds higher than the base year demand at xxi an annual average growth rate of 8.35%. The four supply side scenarios alternatives namely; Reference (REF), Renewable Energy Technologies (RET), Clean Coal Maximum (CCM) and Energy Efficiency and Conservation (EEC) are developed in the LEAP model while considering the resource potential, techno-economic parameters, and CO2 emissions. All four scenarios with various fuel and technology mix, meet the electricity demand during the study period. In terms of CO2 emissions, RET and CCM scenarios have emissions lower than EEC scenario. However, in the REF scenario, CO2 emissions are the highest of all the scenarios. Further, the EEC scenario has the lowest Net Present Value (NPV) requirement followed by REF, RET and CCM scenarios at all the discount rates (4%, 6%, 8%, 10%) considered in the study. The AHP methodology of this study comprises of four main-criteria which include technological, environmental, socio-political and economic criteria and seventeen sub-criteria for the judicious evaluation of the four scenario alternatives of the study. The questionnaire feedbacks under AHP methodology, using a pairwise comparison, determined weightages of the sustainability criteria which were further used towards the ranking of the scenario alternatives. The AHP based sustainability assessment ranks EEC scenario as the most preferred electricity generation scenario followed by REF, RET and CCM scenarios. However, CO2 emissions under EEC scenario are higher than the RET and CCM scenarios, as such, it is recommended that Pakistan should adopt energy efficiency and conservation as the focus of the energy policy alongside increasing the renewable energy share for the electricity generation. The dynamic and performance sensitivity analysis of the AHP decision support framework establishes the robustness of this study. Overall, the results of the developed planning framework are elaborative of the contemplation that how energy policy makers, experts, and stakeholders view future of energy system in Pakistan for next 35 years. The main achievement of this study is the development of a sustainable energy planning framework and providing a future insight pertaining the alternative energy pathways that Pakistan could follow for a sustainable electricity system. This study also proposes a set of policy recommendations that could contribute towards a sustainable energy system and thus sustainable development in Pakistan.