METHOD OF NAPHTHALENE SULPHONATION Russian patent published in 2014 - IPC C07C309/35 C07B45/02 

FIELD: chemistry.

SUBSTANCE: invention relates to technology of organic intermediate products, used in organic synthesis of various substances, in particular to a method of naphthalene sulphonation. The method includes mixing a melted naphthalene-containing raw material with a sulphating agent at a temperature higher than the melting point of the naphthalene-containing raw material, increase of temperature up to 160-168°C and an exposure within the said temperature interval. The sulphating agent is represented by sulphuric acid with a content of the main substance higher than 90%, including regenerated acid. Sulphonation is carried out in a triple system: technical naphthalene sulphonic acid in the form of a mixture of α/β- naphthalene sulphonic acids 10-18:82-90 -naphthalene-containing raw material - sulphating agent. The said raw material and the sulphating agent are supplied separately or together on the layer or under the layer of technical naphthalene sulphonic acid with a volume ratio of raw material + sulphating agent:technical naphthalene sulphonic acid, equal to 1:0.5-1.5.

EFFECT: invention ensures acceleration of naphthalene sulphation and reduction of duration of technological stages of the process with preservation of the target product quality.

4 cl, 2 tbl