Natriumhydrid

BeschreibungSodium hydride, is a binary salt that has a specific hazard of releasing hydrogen upon contact with water. It is an odorless powder that is violently water reactive. The four-digit UN identification number is 1427. The NFPA 704 designation is health 3, flammability 3, and reactivity 2. The white space at the bottom of the diamond has a W with a slash through it, indicating water reactivity.

VerwendenSodium hydride is used to enhance the condensation reactions of carbonyl compounds through the Dieckmann condensation, Stobbe condensation, Darzens condensation and Claisen condensation. It acts as a reducing agent used to prepare diborane from boron trifluoride. It is also used in fuel cell vehicles. Further, it is used to dry some organic solvents. In addition to this, it is involved in the preparation of sulfur ylides, which is utilized for the conversion of ketones into epoxides.

Definitionsodium hydride: A white crystallinesolid, NaH; cubic; r.d. 0.92; decomposesabove 300°C (slow);completely decomposed at 800°C.Sodium hydride is prepared by thereaction of pure dry hydrogen withsodium at 350°C. Electrolysis ofsodium hydride in molten LiCl/KClleads to the evolution of hydrogen;this is taken as evidence for the ionicnature of NaH and the presence ofthe hydride ion (H–). It reacts violentlywith water to give sodium hydroxideand hydrogen, with halogensto give the halide and appropriatehydrogen halide, and ignites spontaneouslywith oxygen at 230°C. It is apowerful reducing agent with severallaboratory applications.