(1-amino-1-phosphonopropyl)phosphonic acid

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of propionitrile (5.5 g, 0.1 mole), phosphorous acid (16.4 g, 0.2 mole), ISOPAR-M (22 g), and wetting agents (0.5 g each) was heated under nitrogen at ambient pressure for 2 hours at 150° C. The product was worked up with ethanol. Colorless crystals of 1-amino-1,1-diphosphono propane (52% yield), m.p. 282° C was obtained.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Into a reactor like the above was charged 261 g phosphorous acid. 44.3 g propionitrile was introduced slowly for 70 minutes at 135°-143° C. into the agitated phosphorous acid. The reactant mixture was held for additional 10 hours at 150°-155° C. The 1-aminopropane-1, 1-diphosphonic acid produced was isolated from the reaction mixture in the manner described in Example 1.

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 54.8 g. of 1-amino propane-1,1-diphosphonic acid and 40 g. of sodium hydroxide are dissolved in 150 cc. of water. 10 g. of sodium hydroxide dissolved in 40 cc. of water and 22 g. of crotonic acid dissolved in 50 cc. of water are added drop by drop simultaneously thereto while stirring vigorously. After continuing stirring for one hour, the temperature of the reaction mixture is increased to 100° C. and the reaction solution is boiled under reflux for 3 hours. It is then slightly acidified with hydrochloric acid. Any turbidity occurring thereby is removed by filtration. After treating the solution with an acid ion exchange agent, the N-(1-carboxy propyl)-1-amino propane-1,1-diphosphonic acid is obtained as an oily residue. This residue is mixed with 100 cc. of ethanol, the ethanol is decanted, and the residue is dried. After continuing stirring for one hour under reflux for 3 hours Any turbidity occurring thereby is removed by filtration After treating the solution with an acid ion exchange agent

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 54.8 g. of 1-amino propane-1,1-diphosphonic acid and 40 g. of sodium hydroxide are dissolved in 150 cc. of water. 10 g. of sodium hydroxide dissolved in 40 cc. of water and 22 g. of crotonic acid dissolved in 50 cc. of water are added drop by drop simultaneously thereto while stirring vigorously. After continuing stirring for one hour, the temperature of the reaction mixture is increased to 100° C. and the reaction solution is boiled under reflux for 3 hours. It is then slightly acidified with hydrochloric acid. Any turbidity occurring thereby is removed by filtration. After treating the solution with an acid ion exchange agent, the N-(1-carboxy propyl)-1-amino propane-1,1-diphosphonic acid is obtained as an oily residue. This residue is mixed with 100 cc. of ethanol, the ethanol is decanted, and the residue is dried. After continuing stirring for one hour under reflux for 3 hours Any turbidity occurring thereby is removed by filtration After treating the solution with an acid ion exchange agent

Conditions: temp:150.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of propionitrile (5.5 g, 0.1 mole), phosphorous acid (16.4 g, 0.2 mole), ISOPAR-M (22 g), and wetting agents (0.5 g each) was heated under nitrogen at ambient pressure for 2 hours at 150° C. The product was worked up with ethanol. Colorless crystals of 1-amino-1,1-diphosphono propane (52% yield), m.p. 282° C was obtained.