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Open Chemistry
|
2005
|
vol. 3
|
issue 4
721-730
EN
The behavior of p-methoxybenzoyldiphenylphosphine oxide, previously synthesized, as a photoinitiator for the polymerization of diacrylate monomer, in the presence of 3% (w/w) tertiary amine (triethyl amine) as synergist additive, was studied. The influence of temperature in the range 30–90°C at 3% (w/w) photoinitiator concentration and the influence of the photoinitiator concentration in the range 0.5–3.5% (w/w) at 30°C was investigated by differential scanning photocalorimetry (photo-DSC). In all experiments the photopolymerization was performed at constant light intensity (3 mW cm−2). The maximum conversion was obtained at temperature of 90°C at 3% (w/w) photoinitiator concentration and 3% (w/w) triethyl amine. The optimal concentration of photoinitiator to obtain maximum conversion was 3% (w/w), at 30°C. No thermal polymerization occurred at higher temperature.
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EN
The present review shows the utility of using mass spectrometry (MS) in obstetrics and gynecology. In this review different gas chromatography / mass spectrometry and liquid chromatography / mass spectrometry methods developed before to be used in obstetrics and gynecology are described. These methods are very useful to determine different hormones in pregnancy, fatty acids esters (related to the use of ethanol) in human meconium and toxic compounds in umbilical cord (as ethanol, steroids, morphine, cocaine, methadone and other drugs). It is also shown in this review the progress during last decades in the field of using mass spectrometry in obstetrics and gynecology (for screening in utero exposure of the child to alcohol, drugs and other toxic compounds). In the field of using mass spectrometry in obstetrics and gynecology are still many problems to solve. For example, the detection of fatty acids esters in meconium has several limitations, which affects the results. One limitation is multiple births. Also in fetal distress, meconium may be passed before birth, and in this case, the collection is impossible. Moreover the meconium is formed starting from the fourth month of pregnancy, so the fetal exposure at any toxic compounds during the first three months cannot be detected at all. To solve all of these, the best would be to combine the results obtained from meconium, with other results obtained from pregnancy serum, placenta or umbilical cord. The main reason for using MS in obstetrics and gynecology is that MS is a noninvasive and a complementary method. It offers the results at a very early point in time, even before the act of birth. Sometimes the use of mass spectrometry is the only alternative. This shows that these methods are of great interest for the future and need to be developed further. [...]
EN
AsV ions were removed by batch equilibrium with FeIII-loaded chelating polymers containing aminophosphinic or aminophosphonic groups. It was effectively removed AsV from a synthetic wastewater as well as from a real drinking water containing 40 μg As per liter. Sorption is best described by pseudo-second order kinetics and a Langmuir isotherm.
EN
Wittig and Wittig-Horner reactions are favorite tools in preparative organic chemistry. These olefination methods enjoy widespread and recognition because of their simplicity, convenience, and effciency. Phase transfer catalysis (PTC) is a very important method in synthetic organic chemistry having many advantages over conventional, homogenous reaction procedures. In this paper, we attempt to summarize the aspects concerning Wittig and Wittig-Horner reactions that take place under phase transfer catalysis conditions.
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