The Reduction of a Solutİon of Sodium Chromate in Hydrdchloric Acid by Methanol

Abstract

The industrially interesting reduction by methanol of a solution of 0.8M sodium chromate in 6M hydrochloric acid has been investigated thermocalorimetrically. The proposed overall stoichiometric equation z 2Na2CrO4(aq) + CH3OH(aq) + 10HCl(aq) + II2O(1) - 2[Cr(H2O)4. aj. CJ(aq) + 4NaCl(aq) + CO2(g) is in agreement with experimental observations at 21.2-70.8°C. The molar ratioMeOH (consumed): CrVI (reduced)—1:1.98 mol/mol; the meanheat of reaction, AH — -0.759 MJ mol-1; and carbon dioxide gas w as proved to be evolved. The experimentally determined activation energy, E = 28.2 kj mol~1,and the order of reaction with respect to methanol, n = 1.81, appear to be inconsistent with the chro¬mate ester mechanism; an alternative reaction mechanism is suggested.

Keywords

• Reduction
• Solutİon
• Chromate

References

1. Communications Faculty of Sciences University of Ankara Series B Chemistry and Chemical Engineering