Triacetoneamine derivatives: Industrial applications and recent developments
Over the last 25 years, the continuous improvements in polymer stabilization have been synonymous with the development of Hindered Amine Stabilization technology. Hindered Amine Stabilizers (H.A.S.) act as long-term Light Stabilizers (H.A.L.S.) as well as long-term Thermal Stabilizers (H.A.T.S.). Their ability to interrupt polymer degradation efficiently by radical scavenging is based on the sterically hindered amine functional group which is able to form stable N-Oxyles as catalytic active intermediates. The starting point in the synthesis of all commercial H.A. S. is 2,2,6,6-tetramethyl-4-piperidone, more known as triacetoneamine (TAA). By reaction at the ketone moiety and/or the hindered amine function respectively, TAA is first transformed to its derivatives, which represent the central building blocks for the stabilizers. By oxidation of TAA or its derivatives the corresponding tetramethylpiperidine-N-oxyles, called TEMPO-products are formed, which can be used, e.g. as polymerization inhibitors, molecular weight regulators, short stoppers or oxidation catalysts. This paper will give a brief overview of current industrial and possible future applications of TAA derivatives as precursors for H.A.S. and TEMPO products. Conventional methodologies as well as some novel developments, e.g. reactive or polymer bounded stabilizers are highlighted.