Catalysis of Organic..

Ostgard et al. 22725. The Treatment of Activated NickelCatalysts for the SelectiveHydrogenation of PynitrileDaniel J. Ostgard, 1 Felix Roessler, 2 Reinhard Karge 2 and Thomas Tacke 11 Degussa AG, Exclusive Synthesis & Catalysts, Rodenbacher Chaussee 4D-63457 Hanau, Germany2 DSM Nutritional Products Ltd, Postfach 3255, CH-4002 Basel, SwitzerlandAbstractdan.ostgard@degussa.comVitamin B1 can, among various other synthetic routes, be prepared via the keyintermediate 5-cyano-pyrimidine (698-29-3) followed by the selective hydrogenationof its nitrile function with a base metal catalyst to the corresponding primary amine“Grewe diamine”. The selectivity of this hydrogenation is typically controlled by theaddition of ammonia and this usually increases the Grewe diamine selectivity up to96.4%. However the current commercial conditions demand that one improves thisselectivity to over 99%. It was found that one could improve the selectivity of theactivated nickel catalyst by treating it with formaldehyde, carbon monoxide, acetoneor acetaldehyde prior to its use. The most productive treatment was withformaldehyde leading to a Grewe diamine selectivity of 99.7% and carbon monoxidewas the next best modifier giving a selectivity of 98.8% for this primary amine. Theother modifiers were clearly less effective. The comparison of the various modifiersand their performances for nitriles other than pynitrile, have indicated that theefficacy of the modifier is dependent on its ability to restructure and decompose onthe catalytic surface leading to the formation of more selective active sites.IntroductionVitamin B1 (a.k.a., thiamin and aneurin) serves a number of essential metabolicfunctions such as the conversion of fats and carbohydrates to energy as well as forthe maintenance of healthy nerves and muscles (1,2). Vitamin B1 occurs naturallyin small amounts in many foods, however it is not stable under conditions of heatand in the presence of alkali, oxygen and radiation (e.g., sunlight). Hence, aconsiderable amount of the naturally occurring vitamin B1 is destroyed during foodpreparation (2,3,4). Since the body has a high vitamin B1 turnover and is not able tostore it very well, the use of vitamin B1 supplements (especially for diets high incarbohydrates and physically active people) is advisable for the avoidance ofdisorders such as Beriberi and the Wernicke-Korsakoff syndrome. Vitamin B1 isproduced on an industrial scale in multiple step syntheses (1) meaning that even thesmallest improvement in the yield of one of the steps can have a large impact on theoverall economics of this product. This is particularly true for the mid-to-later steps