Langyou Chemical
SUPPLEMENTS
Hypophosphorous Acid Preparation Methods
Preparation of hypophosphoric acid
Preparation of hypophosphoric acid
Using yellow phosphorus as raw material
Yellow phosphorus ($P_4 $) reacts with barium hydroxide ($Ba (OH) _2 $) solution under certain conditions. The chemical reaction equation is: $2P_4 + 3Ba (OH) _2 + 6H_2O = 3Ba (H_2PO_2) _2 + 2PH_3 ↑ $. The resulting barium hypophosphite ($Ba (H_2PO_2) _2 $) solution is then metathesis with sulfuric acid ($H_2SO_4 $). The reaction equation is: $Ba (H_2PO_2) _2 + H_2SO_4 = BaSO_4? + 2H_3PO_2 $. The hypophosphoric acid solution can be obtained by filtering to remove the barium sulfate precipitation and concentrating the filtrate. The raw material yellow phosphorus is relatively common in this method, and the reaction principle is clear, but the phosphine ($PH_3 $) gas produced in the process is toxic, and attention should be paid to safety protection and tail gas treatment.
Hydrolysis of phosphorus trichloride ($PCl_3 $) with phosphorus trichloride as raw material
Phosphorus trichloride ($PCl_3 $) can prepare hypophosphoric acid. First, phosphorus trichloride reacts with water, $PCl_3 + 3H_2O = H_3PO_3 + 3HCl $to form phosphoric acid ($H_3PO_3 $) and hydrogen chloride ($HCl $). Then under certain conditions, phosphoric acid further disproportionates to form hypophosphoric acid ($H_3PO_2 $) and phosphoric acid ($H_3PO_4 $). The reaction equation is: $2H_3PO_3 = H_3PO_2 + H_3PO_4 $. By controlling the reaction conditions and subsequent separation and purification steps, higher purity hypophosphoric acid can be obtained. The starting material of this method is easy to obtain phosphorus trichloride, but there are relatively many reaction steps, which requires high control of the reaction conditions.
Preparation of hypophosphoric acid
Using yellow phosphorus as raw material
Yellow phosphorus ($P_4 $) reacts with barium hydroxide ($Ba (OH) _2 $) solution under certain conditions. The chemical reaction equation is: $2P_4 + 3Ba (OH) _2 + 6H_2O = 3Ba (H_2PO_2) _2 + 2PH_3 ↑ $. The resulting barium hypophosphite ($Ba (H_2PO_2) _2 $) solution is then metathesis with sulfuric acid ($H_2SO_4 $). The reaction equation is: $Ba (H_2PO_2) _2 + H_2SO_4 = BaSO_4? + 2H_3PO_2 $. The hypophosphoric acid solution can be obtained by filtering to remove the barium sulfate precipitation and concentrating the filtrate. The raw material yellow phosphorus is relatively common in this method, and the reaction principle is clear, but the phosphine ($PH_3 $) gas produced in the process is toxic, and attention should be paid to safety protection and tail gas treatment.
Hydrolysis of phosphorus trichloride ($PCl_3 $) with phosphorus trichloride as raw material
Phosphorus trichloride ($PCl_3 $) can prepare hypophosphoric acid. First, phosphorus trichloride reacts with water, $PCl_3 + 3H_2O = H_3PO_3 + 3HCl $to form phosphoric acid ($H_3PO_3 $) and hydrogen chloride ($HCl $). Then under certain conditions, phosphoric acid further disproportionates to form hypophosphoric acid ($H_3PO_2 $) and phosphoric acid ($H_3PO_4 $). The reaction equation is: $2H_3PO_3 = H_3PO_2 + H_3PO_4 $. By controlling the reaction conditions and subsequent separation and purification steps, higher purity hypophosphoric acid can be obtained. The starting material of this method is easy to obtain phosphorus trichloride, but there are relatively many reaction steps, which requires high control of the reaction conditions.
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