Migration drivers and migration choice: interrogating responses to migration and development interventions in West Africa

The notion of migration as being at least partly about ‘choice’ is deeply rooted in both academic thought and public policy. Recent contributions have considered migration choice as step-wise in nature, involving a separation between ‘aspiration’ and ‘ability’ to migrate, whilst stressing a range of non-economic factors that influence migration choices. But such nuances have not prevented the emergence of a significant area of public policy that seeks to influence choices to migrate from Africa through ‘irregular’ channels, or at all, through a range of development interventions. This paper explores evidence from West Africa on how young people formulate the boundaries of such choice. Drawing on approaches in anthropology and elsewhere that stress the value of a ‘future-orientated’ lens, we show how present uncertainty is a central framing that fundamentally limits the value of thinking about migration as a choice. This has important implications for policy on ‘migration and development’

Photoacylation of electron-rich quinones: An application of the "photo-Friedel-Crafts reaction"

Schiel C, Oelgemoller M, Mattay J. Photoacylation of electron-rich quinones: An application of the "photo-Friedel-Crafts reaction". SYNTHESIS-STUTTGART. 2001;(8):1275-1279.Irradiation of substituted 1,4-benzo- or 1,4-naphthoquinones in the presence of several aldehydes resulted in the formation of acylated hydroquinones in good yields. In the case of 5-acetyloxy naphthoquinone 8, both regioisomers were formed, but the 2,8-isomer was favored in all cases examined. Even acylated tetrahydroxy naphthalenes became available in good yields by this method

Regioselective photoacylation of substituted naphthoquinones

Schiel C, Oelgemoller M, Mattay J. Regioselective photoacylation of substituted naphthoquinones. JOURNAL OF INFORMATION RECORDING. 1998;24(3-4):257-260.Photoreactions of aldehydes with quinones exhibit acylated hydroquinones in good yields. In the case of substituted naphthoquinones (pos. 5-8) two regioisomers are formed. However, lithium perchlorate as additive affords only one regioisomer. This effect is discussed on the basis of semiempirical calculations

Photoacylations of 2-substituted 1,4-naphthoquinones: a concise access to biologically active quinonoid compounds

Waske PA, Mattay J, Oelgemoller M. Photoacylations of 2-substituted 1,4-naphthoquinones: a concise access to biologically active quinonoid compounds. TETRAHEDRON LETTERS. 2006;47(8):1329-1332.Photochemical acylations of 2-substituted-1,4-naphthoquinones with various aldehydes furnished acylated hydroquinones and acylated quinones in moderate to good combined yields. All reactions are easily performed and open a rapid access to biologically active compounds. For the 2-methyl-1,4-naphthoquinone/butyraldehyde pair, a novel tri-keto compound has been additionally isolated. (c) 2005 Elsevier Ltd. All rights reserved

Green photochemistry: photo-Friedel-Crafts acylations of 1,4-naphthoquinone in room temperature ionic liquids

The photo-Friedel–Crafts acylation of 1,4-naphthoquinone with various aldehydes was investigated in a series of room temperature ionic liquids. High conversions and selectivities were achieved in [C2mim]+-based ionic liquids with the highest isolated yields found in [C2mim][NTf2]. The developed procedure allowed for a replacement of hazardous solvents such as benzene and acetonitrile which are commonly used for this transformation

Green photochemistry: the solar-chemical 'photo-Friedel-Crafts acylation' of quinones

Schiel C, Oelgemoller M, Ortner J, Mattay J. Green photochemistry: the solar-chemical 'photo-Friedel-Crafts acylation' of quinones. GREEN CHEMISTRY. 2001;3(5):224-228.The photoreactions between 1,4-quinones (1 and 4) and aldehydes (2 and 5), yielding acylated hydroquinones as sole products, were investigated under artificial and solar irradiation conditions. Three different solar reactors were used for the photochemical syntheses with sunlight (PROPHIS, CPC and a flat bed reactor), and the CPC system was found to be the most robust one in terms of weather dependence. The solar reactions can be easily performed on a half-kilogram scale using cheap and commercially available starting materials

The "photo-Friedel-crafts acylation" of 1,4-naphthoquinones

Oelgemoller M, Schiel C, Fröhlich R, Mattay J. The "photo-Friedel-crafts acylation" of 1,4-naphthoquinones. EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. 2002;(15):2465-2474.The photochemical reaction between 1,4-naphthoquinone (3) and several aliphatic and aromatic aldehydes 5a-f resulted in the formation of acylated naphthohydroquinones 6a-f in moderate to good yields of 42-79%. When benzaldehyde was used, the dibenzoylated product 7 was also isolated, in 14% yield. The regioselectivity was studied with the unsymmetrical substituted naphthoquinone 4 and butyraldehyde 5b and benzaldehyde 5f. With 5f, the corresponding diaroylated compound 12 was again isolated as a minor product. Oxidation of selected photoproducts afforded the corresponding acylated naphthoquinones 8a, 8b, 8f, and 13 in moderate to excellent yields of 53-94%

Use of Ca-alginate as a novel support for TiO2 immobilization in methylene blue decolorisation

This study provides a preliminary contribution to the development of an industrial process for the UV/TiO2 water treatment by introducing a novel support for TiO2 immobilization. For the following study, Methylene Blue (MB) was chosen as the model dye to evaluate this novel immobilization system. The results showed that TiO2 immobilized in a Ca-alginate bead retained its photoactivity during all of the experiments and the TiO2-gel beads presented good stability in water for maintaining its shape after several uses. When a proportion of 10% (v/v) of these beads was used, the configuration system demonstrated an improved mass transfer and consequently enhanced degradation efficiency. Experiments were also performed using 'recycled' beads. The results showed an increase in the degradation efficiency when the beads were reused, with an eventual 'self-destructive' effect. These studies showed great promise regarding the recyclable reagents with a reduction in waste at no greater cost or reduction in efficiency. Therefore, the potential of TiO2-gel beads as a simple and environmentally friendly catalyst for continuous use was developed.60410811087Dublin City University (DCU), Irelan

Photooxygenations of 1-naphthols: an environmentally friendly access to 1,4-naphthoquinones

Suchard O, Kane R, Roe BJ, et al. Photooxygenations of 1-naphthols: an environmentally friendly access to 1,4-naphthoquinones. TETRAHEDRON. 2006;62(7):1467-1473.Dye sensitized photooxygenations of 1-naphthols were investigated with soluble and solid-supported sensitizers and moderate to excellent yields of the corresponding 1,4-naphthoquinones were achieved in relatively short irradiation times. The mild and environmentally friendly reaction conditions made this application particularly attractive for 'Green Pholochemistry'. Consequently, the photooxygenation of 1,5-dihydroxynaphthalene was Studied with non-concentrated and moderately concentrated sunlight and 5-hydroxy-1,4-naphthoquinone (Juglone) was obtained in yields Lip to 71%. (c) 2005 Elsevier Ltd. All rights reserved