Research On The Synthesis Of 1-alkoxy-4-aminopiperidyl Ultraviolet Absorbent Intermediates

Hindered amine ultraviolet absorbent are one of the most important thermal/light stabilizing agents of polymeric materials against degradation by light and/or heat.However,the normal hindered amine stabilizers can easily be deactivated by the acidic residues from the decomposition of polymers that contain halogen in the molecular structure.The 1-alokyl-hinderamine,especially polymer 1-alkoxyhinderedamine,were significant developed because of their low basicity could protect them from deactivation that caused by acidic residues.The preparation of 1-alkoxy-4-amino-tetramethylpiperidine,a key intermediate of the polymer1-alkoxyhinderedamine ultraviolet absorbents,were researched in this thesis.Using 1-alkoxy-tetramethylpiperidone as start material,the goal product were prepared through indirect reductive amination process and direct reductive amination process respectively.And process parameters of both processes were optimized and screen or develop efficient catalysts to obtain the synthetic process suitable for industrial production of 1-alkoxy-4-amino-tetramethylpiperidine.In the indirect reductive amination process,a imine were firstly synthesized from1-alkoxy-tetramethylpiperidone and butylamine by the method of azeotropic dehydration and the petroleum ether was chosen as entrainer.Then the imine were reduced in hydrogen and different catalysts were used.The results showed that a mixture of skeleton nickel and skeleton Cobalt was the most effective one.In the direct reductive amination process of1-alkoxy-tetramethylpiperidone,skeleton copper showed excellent catalytic activity in.Under optimum conditions,the goal product was obtained in a selectivity of 89% under optimized condition.