A process for producing taurine from alkali ditaurinate or alkali tritaurinate, or their mixture, comprising the conversion of alkali ditaurinate to dialkali ditaurinate or alkali tritaurinate to trialkali tritaurinate, or their mixture, the ammonolysis reaction of ammonia added to a solution of dialkali ditaurinate or trialkali tritaurinate, or their mixture, to yield alkali taurinate, removing excess ammonia from the foregoing and neutralizing alkali taurinates with an acid to form a crystalline suspension of taurine, and recovering taurine by means of solid-liquid separation.

A process for producing taurine from alkali ditaurinate or alkali tritaurinate, or their mixture, comprising the conversion of alkali ditaurinate to dialkali ditaurinate or alkali tritaurinate to trialkali tritaurinate, or their mixture, the ammonolysis reaction of ammonia added to a solution of dialkali ditaurinate or trialkali tritaurinate, or their mixture, to yield alkali taurinate, removing excess ammonia from the foregoing and neutralizing alkali taurinates with an acid to form a crystalline suspension of taurine, and recovering taurine by means of solid-liquid separation.

Isosulfan blue and processes for the preparation thereof are provided. A process is also provided for preparation of the intermediate, 2-chlorobenzaldehyde-5-sulfonic acid, sodium salt of formula (2), used in the preparation thereof and a procedure for the isolation of benzaldehyde-2,5-disulfonic acid, di-sodium salt of the formula (3). Also provided is a process for the preparation of an isoleuco acid of formula (4), which upon oxidation gives rise to isosulfan blue of pharmaceutical grade which can be used for preparation of pharmaceutical formulations. The isolation and purification procedures provided in the process provide substantially pure isosulfan blue with HPLC purity 99.5% or greater.

Isosulfan blue and processes for the preparation thereof are provided. A process is also provided for preparation of the intermediate, 2-chlorobenzaldehyde-5-sulfonic acid, sodium salt of formula (2), used in the preparation thereof and a procedure for the isolation of benzaldehyde-2,5-disulfonic acid, di-sodium salt of the formula (3). Also provided is a process for the preparation of an isoleuco acid of formula (4), which upon oxidation gives rise to isosulfan blue of pharmaceutical grade which can be used for preparation of pharmaceutical formulations. The isolation and purification procedures provided in the process provide substantially pure isosulfan blue with HPLC purity 99.5% or greater.

Complexation of metal ions using chelating agents within a subterranean formation can often be desirable, such as to temper the formation of metal-containing precipitates. However, many chelating agents are produced commercially in an alkali metal salt form that may not be entirely suitable for use downhole, particularly in subterranean formations containing a siliceous material. The working pH range of some types of chelating agents may also be limiting. Treatment fluids comprising an aqueous carrier fluid having an acidic pH, a sulfonated iminodialkanoic acid, and ammonium ions may at least partially address downhole precipitation issues, while providing further advantages as well. Methods for forming sulfonated iminodialkanoic acids can comprise reacting an iminodialkylnitrile with a sultone under acidic conditions to form a fluid comprising a sulfonated iminodialkanoic acid and ammonium ions.

Complexation of metal ions using chelating agents within a subterranean formation can often be desirable, such as to temper the formation of metal-containing precipitates. However, many chelating agents are produced commercially in an alkali metal salt form that may not be entirely suitable for use downhole, particularly in subterranean formations containing a siliceous material. The working pH range of some types of chelating agents may also be limiting. Treatment fluids comprising an aqueous carrier fluid having an acidic pH, a sulfonated iminodialkanoic acid, and ammonium ions may at least partially address downhole precipitation issues, while providing further advantages as well. Methods for forming sulfonated iminodialkanoic acids can comprise reacting an iminodialkylnitrile with a sultone under acidic conditions to form a fluid comprising a sulfonated iminodialkanoic acid and ammonium ions.

Complexation of metal ions using chelating agents within a subterranean formation can often be desirable, such as to temper the formation of metal-containing precipitates. However, many chelating agents are produced commercially in an alkali metal salt form that may not be entirely suitable for use downhole, particularly in subterranean formations containing a siliceous material. The working pH range of some types of chelating agents may also be limiting. Treatment fluids comprising an aqueous carrier fluid having an acidic pH, a sulfonated iminodialkanoic acid, and ammonium ions may at least partially address downhole precipitation issues, while providing further advantages as well. Methods for forming sulfonated iminodialkanoic acids can comprise reacting an iminodialkylnitrile with a sultone under acidic conditions to form a fluid comprising a sulfonated iminodialkanoic acid and ammonium ions.

A process for producing taurine from alkali ditaurinate or alkali tritaurinate, or their mixture, comprising the conversion of alkali ditaurinate to dialkali ditaurinate or alkali tritaurinate to trialkali tritaurinate, or their mixture, the ammonolysis reaction of ammonia added to a solution of dialkali ditaurinate or trialkali tritaurinate, or their mixture, to yield alkali taurinate, removing excess ammonia from the foregoing and neutralizing alkali taurinates with an acid to form a crystalline suspension of taurine, and recovering taurine by means of solid-liquid separation.

A process for producing taurine from alkali ditaurinate or alkali tritaurinate, or their mixture, comprising the conversion of alkali ditaurinate to dialkali ditaurinate or alkali tritaurinate to trialkali tritaurinate, or their mixture, the ammonolysis reaction of ammonia added to a solution of dialkali ditaurinate or trialkali tritaurinate, or their mixture, to yield alkali taurinate, removing excess ammonia from the foregoing and neutralizing alkali taurinates with an acid to form a crystalline suspension of taurine, and recovering taurine by means of solid-liquid separation.

A process for producing taurine from alkali ditaurinate or alkali tritaurinate, or their mixture, comprising the conversion of alkali ditaurinate to dialkali ditaurinate or alkali tritaurinate to trialkali tritaurinate, or their mixture, the ammonolysis reaction of ammonia added to a solution of dialkali ditaurinate or trialkali tritaurinate, or their mixture, to yield alkali taurinate, removing excess ammonia from the foregoing and neutralizing alkali taurinates with an acid to form a crystalline suspension of taurine, and recovering taurine by means of solid-liquid separation.