Study On The Synthesis Of Calcium Formate By Calcium Hydroxide Carbonylation

The calcium formate (CF) is widely applied not only as a new developed feed additive, which is fit for all kinds of animal feed as acidifier acidulant, preservative and antimicrobial, but also as desulfurizer of fuel, food additive, drilling auxiliary in petroleum industry, regulator of plant growing, setting accelerator in the cement industry, tanning auxiliary and so on. More and more attraction has been taken on the synthesis of calcium formate since 1998 when it was approved to be a legal feed additive by Department of Agriculture as feed additive. Synthesis of calcium formate from CO and calcium hydroxide is a green chemical process since the atom economy of this process is 100%.Thermodynamic analysis indicates that the equilibrium constant of the carbon monoxide hydration reaction is smaller than the water gas shift reaction, but the presence of calcium hydroxide which can remove formic acid from carbon monoxide hydration out of the reaction system can promote the reaction continue till the reaction end.The qualitative analysis of the product by means of XRD and IR indicates that small amount of calcium carbonate was formed during the calcium formate formation. The quantity of total calcium ion and calcium formate was measured by complexation titration and oxidation-reduction titration method, by which the yield of calcium formate was calculated.The synthesis of calcium formate from carbon monoxide and calcium hydroxide has been studied in this thesis. The effects of reaction temperature, partial pressure of carbon monoxide, additive and stirring speed on the reaction rate were investigated under the condition that the mole ratio of carbon monoxide and calcium formate is more than 3:1 and the reaction time was long enough for the complete conversion of calcium hydroxide. The experimental results showed that the reaction rate increased with the increase of the reaction temperature, partial pressure of carbon monoxide, pH value and stirring speed, while decreased with the increase of calcium formate concentration. The addition of sodium formate and nitrogen has little effect on the reaction rate.