| 摘要 |
<p>TITLE PRECIPITATION PREVENTION IN AMINE-HYDROGEN D-H EXCHANGE INVENTOR Raymond U. Lemieux To prevent detrimental precipitation of metal amides in the liquid amine phase during amine-hydrogen deuterium-hydrogen exchange, ammonia is removed to cause amides to convert to alkylamides and to maintain the concentration of metal amide below its solubility limit in the amine. The ammonia removal is carried out by distillation with rectification on at least a portion of the amine plus alkali metal alkylamide catalyst solution or on an amine plus ammonia condensate. Even though the partial pressure of ammonia is very low, suitably controlled distillation has been found to remove ammonia, including that in the form of metal amide (by formation of metal alkylamides), and thus prevent any metal amide build-up and precipitation.</p> |
