METHOD OF PRODUCING POLYMETHINE DYES OF RHODACYANINE SERIES Russian patent published in 2019 - IPC C09B23/00 C09B23/16 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to polymethine dyes, particularly to rhodacyanine dyes, which are spectral sensitizers of halogen-silver emulsions used for photomaterials, as well as in holography and microelectronics for laser radiation. Method for production thereof involves condensation of 5-(anilinomethylene)-3-ethyl-rodane with 3-(γ-sulphopropyl)thiazolium betaine in molar ratio of 1:2.1–3.4 respectively. Reaction is carried out in aqueous 10 % hydrogen peroxide solution. Obtained mass is stirred at room temperature for 30 minutes until a homogeneous solution forms, triethylamine is added. One-stage condensation takes place. In 30 minutes after termination of exothermic process the obtained reaction mass is added to aqueous 10 % NaCl solution and left for crystallization for 5–12 hours. Output of end product is 80–96.9 %.

EFFECT: invention increases output of the end product with simplification of synthesis of rhodocyanine dyes and improves the environment by carrying out the process in one step without separating intermediate products and toxic gases into the atmosphere.

1 cl, 5 ex