Tetrabutylammonium Borohydride is a strong reducing agent used in the synthesis of hyperbranched polyglycerol grafting on the surface of silica-coated nanoparticles.
Tetra-n-butylammonium Borohydride can be prepared by the reaction between Sodium Borohydride and tetrabutylammonium chloride. The reagent can also be prepared from the less expensive Tetra-n-butylammonium Iodide by ion exchange.
Purify it by recrystallisation from EtOAc followed by careful drying under vacuum at 50-60o. Samples purified in this way showed no signs of loss of active H after storage at room temperature for more than 1year. Nevertheless samples should be stored at ca 6o in tightly stoppered bottles if kept for long periods. It is soluble in CH2Cl2. [Raber & Guida J Org Chem 41 690 1976, Br.ndstr.m et al. Tetrahedron Lett 3173 1972.]
Crystalline samples showed no loss of active hydrogen after storage at room temperature for more than one year. As with other borohydrides, the material reacts rapidly with aqueous acids to produce hydrogen (potentially borane). Use in a fume hood.
