The photolysis of ethoxalyl azide gives ethoxalylnitrene and ethoxycarbonyl isocyanate. The nitrene adds to C=C double bonds and is inserted into O–H and C–H bonds. At high ethanol concentrations, where the singlet nitrene predominates, the O–H insertion product is formed dominantly. At low ethanol concentrations, where much of the nitrene changes to the triplet state, the hydrogen-abstraction product
N-[2-hydroxy-3-(2H-benzotriazol-2-yl)benzyl]oxamides as light stabilisers
申请人:ELF ATOCHEM NORTH AMERICA, INC.
公开号:EP0593936A1
公开(公告)日:1994-04-27
This invention relates to novel UV absorbers, their methods of preparation, their use in stabilizing polymers and polymers so stabilized against the degradative effects of UV light. The novel compounds of formula I are oxamides which are substituted on one or both nitrogens with
a 2-hydroxy-3-(2H-benzotriazol-2-yl)benzyl group. The 2-hydroxy-3-(2H-benzotriazol-2-yl)benzyl groups are efficient UV absorbing groups and the oxamide group contributes additional light stabilizing, heat stabilizing and metal complexing properties to the compounds. The compounds have low-volatility and are especially useful as UV stabilizers for engineering resins processed at high temperatures.