Ciba-geigy Corporation

Ulrich Kress

Siegfried Kintopf

Rudolf Maul

A process for the preparation of 4-hydroxy-2,2,6,6-tetramethyliperidine (HTMP) by hydrogenation of triacetonamine (TAA) in the presence of an Ni, Co, Ru, Rh, Os or Ir hydrogenation catalyst is described. The process is carried out in the melt without a solvent.

Process for the preparation of 4-hydroxy-2,2,6,6-tetramethylpiperidine

A process for the production of 2-aryl-2H-benzotriazoles comprises reducing and cyclizing the corresponding o-nitroazobenzenes with hydrogen at a temperature in the range of about 20.degree. C. to about 100.degree. C. and at a pressure in the range of about 15 psia (1 atmosphere) to about 1000 psia (66 atmospheres) in an organic solvent mixture containing an organic amine at a pH over 10 in the presence of noble metal hydrogenation catalyst, preferably palladium. High yields of pure product are obtained with a concomitant reduction of undesired by-products and a reduction in effluent pollution problems.

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Bensheim/Bergstrasse, Germany

Ulrich Kress