Oxygen attack

Next in what amounts to an intramolecular Williamson ether synthesis the alkoxide oxygen attacks the carbon that bears the halide leaving group giving an epoxide As m other nucleophilic substitutions the nucleophile approaches carbon from the side oppo site the bond to the leaving group... 

Oxidation of LLDPE starts at temperatures above 150°C. This reaction produces hydroxyl and carboxyl groups in polymer molecules as well as low molecular weight compounds such as water, aldehydes, ketones, and alcohols. Oxidation reactions can occur during LLDPE pelletization and processing to protect molten resins from oxygen attack during these operations, antioxidants (radical inhibitors) must be used. These antioxidants (qv) are added to LLDPE resins in concentrations of 0.1—0.5 wt %, and maybe naphthyl amines or phenylenediamines, substituted phenols, quinones, and alkyl phosphites (4), although inhibitors based on hindered phenols are preferred. 

Oxygen attacks mbber because of the presence of two unpaired electrons... 

Material of construction The materials of fabrication for this type of packing are more critical to long life due to pad size, wall thickness of metal or plastic components, and actual selection based on the system corrosion, hydrogen attack, and oxygen attack in the column environment. 

Second, oxygen attacks the metal directly by precipitating iron oxide at the anode, thus, preventing anodic polarization by Fe ions. 

The oxidation method can also be applied to asymmetrically substituted 1,3-diaryltriazenes. The oxygen attacks the nitrogen atom nearest to an electron-releasing... 

In a neutral solution, dissolved oxygen attacks iron as follows,... 

In one of their notable examples, the hydroboration polymerization of low molecular weight allyl-telechelic polyisobutylene with tripylborane (trip = 2,4,6-triisopropylphenyl) was found to yield air-stable organoboron segmented block copolymers. These boron main-chain polymers (8) (Fig. 8), unlike the general ones, were stable to air. The stability was due to the steric hindrance of the bulky tripyl groups preventing oxygen attack of the borons.28... 

The alcohol oxygen attacks the sulfur atom of the sulfonyl chloride. 

Conjugated dienes and polyenes lead to unique cases of conjugated oxidations, such as the formation of endoperoxide by singlet oxygen attack on the endo-diene, e.g. u-terpinene29. 

The nucleophilic attack of the water or hydroxide species takes place in an anti fashion i.e. the oxygen attacks from outside the palladium complex and the reaction is not an insertion of ethene into the palladium oxygen bond. This has been demonstrated in a model reaction by Backvall [4], The reaction studied was the Wacker reaction of dideuterio-ethene (cis and trans) in the presence of excess of LiCl, which is needed to form 2-chloroethanol as the product instead of ethanal. The latter product would not reveal the stereochemistry of the attack Note that all of the mechanistic work has been carried out, necessarily, on systems deviating in one aspect or another from the real catalytic one. The outcome depends strongly on the concentration of chloride ions [5],... 

Phosphine in small quantities in hydrogen containing over I per cent, of oxygen attacks copper, producing an acid liquid which has a most corrosive action on fabric. However, it does not appear under these circumstances to have any action on aluminium or zinc consequently any metal parts inside the envelope of an airship should be of aluminium. Phosphine under the above conditions attacks hemp and other textiles which have been treated with copper compounds, but it does not appear to have any action on fabrics free from copper compounds or copper or brass fastenings. 

Atomic oxygen attacks and destroys enzymes and other protein molecules, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) molecules, and other essential biochemical molecules, interrupting... 

Little is known about valence-shell expansion reactions among still higher row elements, but the considerable oxidative stability of silicones and of tetraalkyl derivatives of group IV elements suggests that valence shell-expansion doesn t provide an easy path for oxygen attack in this group. 

---