The present invention relates to a method for preparing lycopene crystals with high purity and low harm. The method comprises the following steps: (1) mixing lycopene oleoresin with a mixed solvent consisting of an alkane and a lower alcohol, and heating and stirring same for dissolution to form a homogenous solution; (2) cooling and crystallizing the homogenous solution, filtering same to obtain a filter cake; (3) washing the filter cake successively using a lower alcohol and an alkane, and drying same to obtain lycopene crystals. According to the method provided by the present invention, lycopene crystals can be obtained using a mixed solvent by means of one step crystallization, and the crystal content is further improved and harmful substances in the crystals are reduced by means of a two-step crystal washing process to obtain lycopene crystals with high purity and low harm. The method is fast and convenient, lycopene crystals with high purity, low harm, and safety can be produced, and the method is suitable for industrial production.

Process for preparing disodium 5,5-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5-indigosulfonic acid, iii) the leuco-5,5-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5-indigosulfonate.

Process for preparing disodium 5,5-indigosulfonate, the feedstock being indigo, this process including the following steps: i) the indigo is subjected to a sulfonation treatment resulting in a mixture that contains 5,5-indigosulfonic acid, this process including: ii) a reduction treatment is applied to the mixture obtained in step i), and optionally a purification step, so as to obtain a composition including leuco-5,5-indigosulfonic acid, iii) the leuco-5,5-indigosulfonic acid is isolated from the composition resulting from step ii), iv) the leuco-5,5-indigosulfonic acid resulting from step iii) is oxidized to give disodium 5,5-indigosulfonate.

The present invention relates to an improved process for preparation of Indigo carmine of Formula (I), in high purity, more than 99.5%.

Aqueous leucoindigo solution comprising an aromatic amine, in particular aniline or aniline and N-methylaniline, wherein the concentration of the aromatic amine is below 200 ppm, wherein the leucoindigo salt in the solution is in the form of a mixed sodium and potassium salt, wherein the molar ratio of sodium to potassium is in the range of from above 3:1 to 10:1, preferably wherein the concentration of the salt is in the range of from above 25 to 45% by weight, based on the total weight of the solution.

A process for the preparation of diaminophenothiazinium compounds is described, which allows achieving quickly and effectively a high degree of purity of the same.

An object of the present invention is to provide a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both. The present invention is a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both, the method comprising treating the material containing geniposide or genipin or both using an activated carbon having (a) a methylene blue adsorption ability of 50 ml/g or more; and (b) an iodine adsorption ability of 750 mg/g or more, thereby removing geniposide or genipin or both.

Method of making an aqueous aniline-free or aniline-free and N-methylaniline-free leucoindigo solution from an aqueous leucoindigo solution comprising aniline or aniline and N-methylaniline, the concentration of aniline or aniline and N-methylaniline being determined according to ISO 14362-1:2017(E), wherein said leucoindigo is in the form of an alkali metal salt, the method comprising at least steps (A) to (C): (A) providing a liquid stream comprising said aqueous leucoindigo solution comprising said amine(s); (B) providing a purification stream; (C) bringing into contact said liquid stream with said purification stream.

Aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt;

wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and
wherein the concentration of the leucoindigo salt is in a concentration range of from 15 to 45% by weight based on the total weight of the solution, and wherein the solution is stable at a temperature of 23 C.; or
wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the solution is stable at a temperature of 60 C.

An object of the present invention is to provide a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both. The present invention is a method for removing geniposide or genipin or both from a material containing geniposide or genipin or both, the method comprising treating the material containing geniposide or genipin or both using an activated carbon having (a) a methylene blue adsorption ability of 50 ml/g or more; and (b) an iodine adsorption ability of 750 mg/g or more, thereby removing geniposide or genipin or both.