Transition metal ions carbonyl compounds

Complexation studies of sensors 83 and 84 with the alkali, alkaline earth, and transition metal ions Cu2+, Ni2+, Zn2+, Cd2+, and Pb2+ were performed in Valeur s laboratory.141,142 In these compounds, the chromophores are linked to the azacrowns in such a way that the cations interact directly with the carbonyl group that acts as an electron-withdrawing unit. Therefore, when an ion is coordinated,... 

Ueda et al. (37) have proposed magnesium oxide catalyst modified with a transition metal ion (M/MgO) for the vinylation of methyl propionate and acetonitrile. Acetonitrile is vinylated to acrylonitrile selectively (94% selectivity at about 10% conversion) over Cr/MgO catalysts at 350 C in the absence of oxygen. The selectivity for the vinylation of methyl propionate over Mn/MgO catalysts is not different from the value obtained with Ti -TSM in the presence of oxygen. The catalyst system, however, is not effective for the reaction of acetic acid. We conducted the reaction of acetonitrile and methanol over Ti -TSM in the presence of oxygen, and found that the vinylation does not take place but the hydrolysis to acetic acid and subsequent esterification with methanol into methyl acetate proceed preferentially. It is likely that Ti -TSM is an appropriate catalyst for the vinylation of carbonyl compounds and M/MgO is appropriate for the vinylation of nitriles. 

The results obtained in this work indicate that the selectivity of platinum catalysts for the hydrogenation of unsaturated carbonyl compounds can be markedly improved by doping the carrier with a monolayer of transition metal ion. It is also worth to note that sandwich-type catalysts (ZrC>2/Pt/Zr02/Ti02) are also active and selective in the studied reaction. We believe that on the surface of this system, the end-on adsorption of aldehyde molecule has been forced. 

Polymer manufacture Unsaturation, Transition metal ions (hydroperoxide, carbonyl compounds by adventitious oxidation)... 

Processing and fabrication Hydroperoxides, carbonyl compounds (by high temperature oxidation, limited oxygen supply) Transition metal ions (from machinery or compounding ingredients)... 

It is reported that some aromatic compounds were detected in polyethylene as impurities (51, 52) although it is not clear where they came from. Aromatic molecules have absorption in the UV regions, and some kinds of aromatic molecules are known to sensitize the photodecomposition of hydrocarbons, ethers, alcohols, and polydimethylsil-oxane (53). This sensitization involves an energy-transfer process, which will be described later in some detail. The presence of radical generators, such as transition metal ions and carbonyl compounds, in polymers will also initiate photodegradation. 

Processing and fabrication Oxygenated moieties hydroperoxides and carbonyl compounds formed by high temperature oxidation Transition metal ions from machinery or compoimding ingredients... 

---