Method for producing aluminum salts of cyclic phosphinic acids

A process for preparing an aluminum salt of a cyclic phosphinic acid, which comprises reacting the cyclic phosphinic acid with aluminum hydroxide in the presence of water and in the absence of a polar solvent selected from the group consisting of acetic acid, propionic acid, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and acetonitrile at an elevated temperature for a reaction time of from 1 to 20 hours and wherein the process is carried out in an autoclave.

The process as claimed in clam 2, wherein one mole of the cyclic phosphinic acid is reacted with ⅓ of the mole of the aluminum hydroxide in the presence of from 0.5 to 3 ml of the water, calculated per gram of acid.

A process for preparing an aluminum salt of a cyclic phosphinic acid, which comprises reacting the cyclic phosphinic acid with aluminum hydroxide in the presence of water and in the absence of a polar solvent selected from the group consisting of acetic acid, propionic acid, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and acetonitrile at an elevated temperature for a reaction time of from 1 to 10 hours and wherein the reaction is carried out in an autoclave under an autogenous pressure.

A process for preparing an aluminum salt of a cyclic phosphinic acid, which comprises reacting the cyclic phosphinic acid with aluminum hydroxide in the presence of water and in the absence of a polar solvent selected from the group consisting of acetic acid, propionic acid, methanol, ethanol, propanol, butanol, acetone methyl ethyl ketone, tetrahydrofuran, dioxane and acetonitrile at an elevated temperature for a reaction time of from 1 to 10 hours and at a pressure from 2 to 10 bar.