@article{Shteinberg_2022, title={СATALYTIC METHOD FOR THE SYNTHESIS OF 3-HYDROXY-2-NAPHTOIC ACID ANILIDE}, volume={88}, url={https://ucj.org.ua/index.php/journal/article/view/487}, DOI={10.33609/2708-129X.88.10.2022.91-103}, abstractNote={<p>Arylamides of 3-hydroxy-2-naphthoic acid are widely used in the production of organic azo pigments, as medicines and pesticides.</p> <p>Titanium tetrachloride, tetrabutoxytitanium and polybutoxytitanates, previously used for the synthesis of the most important of them., 3-hydroxy-2-naphthoic acid anilide by boiling of the latter in aniline (184&nbsp;°C), proved to be ineffective as catalysts in carrying out this reaction in <em>ortho</em>-xylene.</p> <p>The study of the reasons for this inhibition of catalysis showed that it can be associated with the interaction of Ti(4+) with the hydroxy group of 3-hydroxy-2-naphthoic acid, its oxidation, accompanied by a decrease in the effective charge of titanium.</p> <p>Taking into account this inhibition, in the search for new catalysts for the synthesis of 3-hydroxy-2-naphthoic acid anilide, the known literature data on the oxidizing ability (according to the values of the reaction rate constant <em>k</em>) with respect to phenoxyl radicals of a number of Lewis acids, including titanium tetrachloride, were used:</p> <p>SbCl<sub>5</sub><strong>&gt;</strong>TiCl<sub>4 </sub><strong>&gt;</strong>SnCl<sub>4</sub><strong>&gt;</strong>PCl<sub>5</sub><strong>&gt;</strong>AlCl<sub>3</sub></p> <p><em>k</em>, l·mol<sup>-1</sup>·sec<sup>-1</sup>&nbsp;&nbsp; 10<sup>5</sup>&nbsp;&nbsp;&nbsp;&nbsp; 157&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 156&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 42&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 18.</p> <p>This made it possible to choose phosphorus trichloride as an effective catalyst. It is shown that this compound, in an amount of only 2% mole. from 3-hydroxy-2-naphthoic acid, allows in boiling <em>ortho</em>-xylene (145&nbsp;°C), under relatively mild conditions, compared to boiling aniline (184&nbsp;°С), to obtain anilide 3-hydroxy-2-naphthoic acid (by reaction of the latter with aniline) of good quality with a practically quantitative yield.</p> <p>Antimony trifluoride also has similar pro­perties as a catalyst, at the level of efficiency of phosphorus trichloride.</p> <p>The ability of catalysts to act as an oxidizing agent should, apparently, always be taken into account during the catalytic amidation of aromatic oxycarboxylic acids at elevated temperatures.</p&gt;}, number={10}, journal={Ukrainian Chemistry Journal}, author={Shteinberg, Leon}, year={2022}, month={Nov.}, pages={91-103} }