Modification and scaling of industrial synthesis of naphazoline nitrate substance using green chemistry approaches

This article presents the results of the modified and optimized synthesis technology of the Naphazoline nitrate substance introduced into the industrial synthesis and included in the registration dossier. The introduction of the 1,2,4-trichlorobenzene solvent into the synthesis scheme at the condensation stage made it possible to increase the yield of the substance by up to 50% compared to the traditional technology. The final product Naphazoline nitrate meets the requirements of the European Pharmacopoeia monograph and has high purity, suitable particle size, high homogeneity, easy industrialization and high productivity. The assay of the substance was increased from 98.7% to 100.0%, and the total of impurities was reduced from 0.5% to 0.1% and below. Carrying out the regeneration of the 1,2,4-trichlorobenzene solvent improves the indicator of economic efficiency due to the possibility of its repeated use. The calculated E-factor for the modified technology is 7 times higher compared to the traditional one, which indicates a reduction in the amount of waste, and therefore a reduction in the negative impact on the environment and production personnel.