The method described herein provides a method for preparing trisilylamine. In one aspect, the method comprises: providing a reaction mixture of trisilylamine and monochlorosilane into a reactor wherein the reaction mixture is at a temperature and pressure sufficient to provide trisilylamine in a liquid phase wherein the reaction mixture is substantially free of an added solvent; contacting the reaction mixture with ammonia to provide a crude mixture comprising trisilylamine and an ammonium chloride solid wherein monochlorosilane is in stoichiometric excess in relation to ammonia; purifiying the crude mixture to provide trisilylamine wherein the trisilyamine is produced at purity level of 90% or greater; and optionally removing the ammonium chloride solid from the reactor.