Crystal structure and identification of resonance forms of diethyl 2-(3-oxoiso-1,3-dihydrobenzofuran-1-ylidene)malonate

The research leading to these results received funding from the European Community's Seventh Framework Programme ([FP7/2007–2013]) under grant agreement No. 607411 (MC-ITN EREAN: European Rare Earth Magnet Recycling Network).The reaction of diethyl malonate with phthaloyl chloride in acetonitrile in the presence of triethylamine and magnesium chloride results in the formation of the title compound, diethyl 2-(3-oxo-1,3-dihydro-2-benzofuran-1-ylidene)propanedioate, C15H14O6. One of the ester groups of the diethyl malonate fragment is almost coplanar with the isobenzofuran unit, while the plane of the other group is perpendicular to it [dihedral angles = 5.45(3) and 83.30(3)°, respectively]. The C—C and C—O distances both in the heterocyclic furan ring and the diethyl malonate fragment are indicative of the dipolar delocalization occurring within the isobenzofuran unit. This delocalization is likely to be responsible for the unusual intermolecular O···O contact [2.756(2)Å], established between the O atom of the furan ring and the carbonyl O atom of the diethyl malonate fragment. In the crystal, weak C—H···O interactions are observed, which link the molecules into [100] chains.Publisher PDFPeer reviewe

Laboratory study on the mobility of major species in fly ash–brine co-disposal systems: up-flow percolation test

Apart from the generation of fly ash, brine (hyper-saline wastewater) is also a waste material generated in South African power stations as a result of water re-use. These waste materials contain major species such as Al, Si, Na, K, Ca, Mg, Cl and SO4. The co-disposal of fly ash and brine has been practiced by some power stations in South Africa with the aim of utilizing the fly ash to capture the salts in brine. The effect of the chemical interaction of the species contained in both fly ash and brine, when co-disposed, on the mobility of species in the fly ash–brine systems is the focus of this study. The up-flow percolation test was employed to determine the mobility of some major species in the fly ash–brine systems. The results of the analysed eluates from the up-flow percolation tests revealed that some species such as Al, Ca and Na were leached from the fly ash into the brine solution while some species such as Mg, Cl and SO4 were removed to some extent from the brine solution during the interaction with fly ash. The pH of the up-flow percolation systems was observed to play a significant role on the mobility of major species from the fly ash–brine systems. The study showed that some major species such as Mg, Cl and SO4 could be removed from brine solution using fly ash when certain amount of brine percolates through the ash.Web of Scienc

Working memory, psychiatric symptoms, and academic performance at school. Neurobiology of Learningand Memory

Abstract Previous studies of the relationship among working memory function, academic performance, and behavior in children have focused mainly on clinical populations. In the present study, the associations of the performance in audio-and visuospatial working memory tasks to teacher reported academic achievement and psychiatric symptoms were evaluated in a sample of fifty-five 6-13-year-old school children. Working memory function was measured by visual and auditory n-back tasks. Information on incorrect responses, reaction times, and multiple and missed responses were collected during the tasks. The childrenÕs academic performance and behavioral and emotional status were evaluated by the Teacher Report Form. The results showed that good spatial working memory performance was associated with academic success at school. Children with low working memory performance, especially audiospatial memory, were reported to have more academic and attentional/behavioral difficulties at school than children with good working memory performance. An increased number of multiple and missed responses in the auditory and visual tasks was associated with teacher reported attentional/behavioral problems and in visual tasks with teacher reported anxiety/depressive symptoms. The results suggest that working memory deficits may underlie some learning difficulties and behavioral problems related to impulsivity, difficulties in concentration, and hyperactivity. On the other hand, it is possible that anxiety/depressive symptoms affect working memory function, as well as the ability to concentrate, leading to a lower level of academic performance at school

Screening of untreated municipal solid waste incineration fly ash for use in cement-based materials: chemical and physical properties

The environmental impact during concrete manufacturing can be reduced by using less cement or using types of cement with high amounts of secondary cementitious materials (SCMs) and fillers. Fly ash from municipal solid waste incineration (MSWI) is an unused material, which could potentially be used as an SCM or filler. The applicability of MSWI fly ash samples in cement-based materials was investigated through an indirect determination based on the chemical composition, toxic metal content and particle size distribution of the samples. Furthermore, how the samples compared to each other and how representative the samples were for MSWI fly ash, in general, were investigated by multivariate modelling. MSWI fly ash samples were obtained from Denmark, Sweden and Greenland. Comparing the chemical composition of the MSWI fly ash samples with the chemical requirements for coal fly ash to be used in concrete, specified in EN 450-1 2012, indicated a low potential as SCMs. Additionally, the MSWI fly ash contained and leached more toxic metals than the allowed limits. The particle size distributions were larger than cement and indicated limited potential as filler. A principal component analysis showed that the obtained samples were chemically different materials compared to each other and would have different effects if used in cement-based materials. Additionally, the samples from Denmark were unrepresentative of MSWI fly ash, while the Greenlandic and Swedish samples were comparable to previously studied MSWI fly ash samples

Screening of untreated municipal solid waste incineration fly ash for use in cement-based materials: chemical and physical properties

The environmental impact during concrete manufacturing can be reduced by using less cement or using types of cement with high amounts of secondary cementitious materials (SCMs) and fillers. Fly ash from municipal solid waste incineration (MSWI) is an unused material, which could potentially be used as an SCM or filler. The applicability of MSWI fly ash samples in cement-based materials was investigated through an indirect determination based on the chemical composition, toxic metal content and particle size distribution of the samples. Furthermore, how the samples compared to each other and how representative the samples were for MSWI fly ash, in general, were investigated by multivariate modelling. MSWI fly ash samples were obtained from Denmark, Sweden and Greenland. Comparing the chemical composition of the MSWI fly ash samples with the chemical requirements for coal fly ash to be used in concrete, specified in EN 450-1 2012, indicated a low potential as SCMs. Additionally, the MSWI fly ash contained and leached more toxic metals than the allowed limits. The particle size distributions were larger than cement and indicated limited potential as filler. A principal component analysis showed that the obtained samples were chemically different materials compared to each other and would have different effects if used in cement-based materials. Additionally, the samples from Denmark were unrepresentative of MSWI fly ash, while the Greenlandic and Swedish samples were comparable to previously studied MSWI fly ash samples

Crystal structure and identification of resonance forms of diethyl 2-(3-oxoiso-1,3-dihydrobenzofuran-1-ylidene)malonate

The reaction of diethyl malonate with phthaloyl chloride in acetonitrile in the presence of triethylamine and magnesium chloride results in the formation of the title compound, diethyl 2-(3-oxo-1,3-dihydro-2-benzofuran-1-ylidene)propanedioate, C15H14O6. One of the ester groups of the diethyl malonate fragment is almost coplanar with the isobenzofuran unit, while the plane of the other group is perpendicular to it [dihedral angles = 5.45(3) and 83.30(3)°, respectively]. The C—C and C—O distances both in the heterocyclic furan ring and the diethyl malonate fragment are indicative of the dipolar delocalization occurring within the isobenzofuran unit. This delocalization is likely to be responsible for the unusual intermolecular O···O contact [2.756(2)Å], established between the O atom of the furan ring and the carbonyl O atom of the diethyl malonate fragment. In the crystal, weak C—H···O interactions are observed, which link the molecules into [100] chains