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The dynamics of the bimolecular quenching of triplet excited benzophenone by anisole was studied by nanosecond flash photolysis. We carried out a detailed study of the solvent dependence of the reaction rates and efficiencies in a number of protic and non-protic solvents. These studies were augmented by theoretical modelling and experimental investigation of solute/solvent interactions in the triplet excited and the ground state, respectively. The triplet quenching that follows Stern-Volmer kinetics in all cases is profoundly dependent on the nature of the solvent, with the highest reactivity being consistently found in protic solvents. The results in non-protic solvents are compatible with unproductive quenching via a charge-transfer state, whereas the generally fast quenching in protic solvents is accompanied by efficient formation of free-radical products. Analysis of the solvent dependence in terms of Marcus theory reveals the impact of specific solvation of benzophenone by protic solvents on the ET driving force and kinetics. Specific solvation is found to support efficient free radical ion formation in media of moderate and low polarity as well.

To be or not to be solvated is the decisive parameter that controls the photoinduced hydrogen-atom transfer in diastereomeric ketone/phenol dyads. A kinetic solvent effect that refers to hydrogen bonding between the phenol and the solvent is suggested to be the main source of the stereoselective discrimination in the hydrogen transfer (see figure).

LCA is a popular tool widely used to assess the environmental impact of waste management systems, which is illustrated by the substantial number of LCA computer models specifically addressing this subject. Due to the complex nature of waste management modelling and the range of country-specific data, as well as lack of harmonization, it has been observed that there are large discrepancies between the results using different models. Many studies have underlined the necessity of clearly identifying both the scope and methodological assumptions of LCAs in order to have confidence in the results. Therefore, the paper presented here reveals several methodology-related issues. The study tests two different pieces of LCA software, i.e. IWM-2 (designed specifically for MSW) and SimaPro (a generic and widely used LCA software). The pieces of software were used to LCA an MSW scenario and the results obtained (calculated using Ecoindicator'99 H/A) were compared to show the strengths and weaknesses of these tools, i.e., generic software usually treats the waste as a set of separate fractions, not as a whole mass, which means that the software is not highly sensitive to the composition of the waste and does not take into account the environmental impacts produced as a result of the interaction between the waste components after mixing. As waste composition is very important in planning, one study combines these two software packages to get final results, i.e., data generated by IWM-2 were entered into SimaPro. The discussion is built around a case study in Poland where waste management scenarios have been analyzed. The research carried out has shown that having the same initial inventory data collected on the basis of the same assumptions and with the same boundaries to the system model used and using the same method of LCIA to assess the impact on the environment, may not produce the same end results. In the presented study, the main differences in the LCIA results appeared in four output-related impact categories: carcinogens, climate change, ecotoxicity, and eutrophication/acidification, and for one input related impact category -fossil fuels. Four reasons responsible for these differences are identified:(1) The IWM-2 program identified a smaller number of substances emitted to air and water associated with landfill and recycling than the Ecoinvent database (IWM-2 identified a total of 31 types of emissions to air

Purpose The paper presents, for the first time, a life cycle assessment (LCA) study of energy generation (i.e. electricity and heat production) in Poland. The aim is to determine and compare the potential impact of energy generation upon the environment in 2007, 2010 and 2012 based on countryspecific data bought from specialised government agencies. Methods LCA evaluations were made using the Impact2002+ method, which proposes a feasible implementation of a combined midpoint/damage approach. The method was chosen because it models risks and potential impacts per emission for several thousand chemicals, including greenhouse gas (GHG). The LCA method was used to monitor and assess the current energy system and introduced changes in energy structure at national level. Results and discussion From the environmental perspective, the main problem of the Polish energy sector is that it is mainly based on fossil energy carriers, i.e. hard and brown coal (over 80 %). As the share of renewables in primary energy has increased from 6.7 to 10.2 % (mainly biomass), a reduction in SO 2 , NO x and dust was noted in 2010 in comparison to 2007. Unfortunately, acid and CO 2 emissions increased significantly in 2012 as a result of higher consumption of brown coal as a fuel for energy production. The LCA study shows that the total environmental impact of the production and distribution of 1 TJ of energy increased by about 4 % in 2010 (compared to 2007) and by about 11 % in 2012 (compared to 2010). Conclusions Specific representative data of high quality can be delivered by agencies focused on energy issues and the national statistical office. They can help to considerably reduce the time and costs of life cycle inventory (LCI). These data, including a classification relating to electricity and heat generation and distribution in Poland, were converted to LCA results for the first time. It was noted that allocation between heat and power in the CHP system can be recognised as a source of uncertainty, and the results should be interpreted as sensitive to change in the allocation criteria.