Metal Sulfate Catalyst for CCl₂F₂ Decomposition in the Presence of H₂O

Abstract

Activities for the hydrolysis of CCl 2 F 2 (CFC-12) on various metal sulfates were investigated in this study. It was found that Zr(SO 4 ) 2 exhibits a high activity for CFC-12 decomposition and a high selectivity to CO 2 . On the other hand, the metal sulfates Al 2 (SO 4 ) 3 , La 2 (SO 4 ) 3 , Ce 2 (SO 4 ) 3 , and Cr 2 (SO 4 ) 3 were also active for the hydrolysis of CFC-12. However, the activities for CFC-12 decomposition of MnSO 4 , CoSO 4 , and MgSO 4 were low, and decomposition of CFC-12 hardly occurred on the metal sulfates CaSO 4 , SrSO 4 , and BaSO 4 . Among the investigated metal sulfates, Zr(SO 4 ) 2 was the most active, and the complete decomposition of CFC-12 was achieved at 598 K. The CFC-12 decomposition rate monotonically increased with increasing CFC-12 partial pressure. On the other hand, CFC-12 conversion became highest at an oxygen content of 18.9 mol % and a H 2 O content of 5 mol %. Therefore, the main reaction on Zr(SO 4 ) 2 for CFC-12 decomposition into CO 2 and HCl and HF is the hydrolysis reaction. The high activity to CFC-12 decomposition on Zr(SO 4 ) 2 was stably sustained over the 40-h period examined. Therefore, the metal sulfate Zr(SO 4 ) 2 is highly active for the hydrolysis of CFC-12 and has sufficient stability against fluorination and/or chlorination.

Preparation, characterization, and photocatalytic activity of sulfate-modified titania for degradation of methyl orange under visible light

“…Modification of the titania with different anions such as SO 2− 4 , PO 3− 4 , and WO 2− 4 has been found to enhance the acidity and certain other physicochemical properties of the catalyst, such as thermal stability and mesoporosity [34][35][36]. In particular, sulfation of semiconductor photocatalysts is of great interest for scientists and engineers because it has an enormous potential for environmental pollutant remediation [37][38][39][40].…”

Preparation, Crystal Structure and Spectroscopic Characterization of [Ga(OH)(SO4)(terpy)(H2O)] · H2O (terpy=2,2’:6’,2-Terpyridine): The First Characterized Gallium(III) Sulfato Complex

“…Metal-sulfato species have been studied for their important roles in catalysis [19], in the field of porous-framework materials [20], in stabilizing Pt III -Pt III species [21], in the chemistry of cisplatin analogues [22] and as models of the active sites of important enzyme systems that have the sulfate anions as substrate, e. g. ATPsulfurylases [1,23].…”

Synthesis and Structural Characterization of a New Tetranuclear Nickel(II) Sulfato Complex Containing the Anionic Form of Di-2-Pyridyl Ketone Oxime

“…The sulfate ion [41] is a ligand with great coordinative flexibility (μ 2 , μ 3 , μ 4 , μ 5 , μ 6 , μ 8 , or μ 10 potential), see Scheme 2. Metal-sulfato complexes have been studied for their roles in the field of porous framework materials [42,43], in catalysis [44], in the construction of luminescent molecular materials [45,46], and in medicinal [47], environmental [48], and bioinorganic [49] chemistry. The possible advantages of using SO 4 2− instead of R CO 2 − include (i) the possibility of triggering aggregation of preformed smaller cationic species into new, higher-nuclearity products and (ii) the possible diversion of known reaction systems developed using monoanionic carboxylates to new species as a result of the higher charge and higher denticity/bridging capability of sulfates.…”