Synthesis of tetraalkylammonium thiometallates in aqueous solution

An aqueous solution method for the preparation of tetraalkylammonium thiometallates (R4N)(2)MS4 (R = pentyl or hexyl and, M = Mo or W) is reported. The one-step rapid substitution of [NH4](+) ions from ammonium thiomolybdate (ATM) and ammonium thiotungstate (ATT) with [(pentyl)(4)N](+) and [(hexyl)(4)N](+) ions during reactions with (pentyl)(4)NBr and (hexyl)(4)NBr, respectively, is described. One application for these tetraalkylammonium thiomolybdates and thiotungstates is as precursors for MoS2 and WS2 catalysts, which are used in industrial hydrodesulfurization and hydrodenitrogenation processes. The synthesized thiometallates were characterized using the spectroscopic techniques Fourier transform infra red (FTIR), ultra violet (UV) and, nuclear magnetic resonance (C-13 NMR) for determining their chemical structures. Thermal analyzes (TGA-DTA) were done to study the fragmentation and decomposition behavior of their molecular structures. (C) 2001 Elsevier Science B.V. All rights reserved.