SYNTHESIS OF 3-HYDROXY-2-NAPHTHOIC ACID ANILIDE CATALYZED BY PHOSPHORUS (III) COMPOUNDS IN VARIOUS MEDIA

Catalysis with phosphorus P(III) compo­unds (phosphorus trichloride and phospho­rous acid) in the acylation of aniline 3=hydroxy=2=naphthoic acid various media (toluene, octane, chlorobenzene, para=­xylene, ortho=xylene, ortho=chlorotoluene, mesitylene, pseudocumene, n.=deсan, ortho= di­chlo­ro­benzene, mixtures ortho=xylene nitrobenzene) upon boiling vigorous distillation water leads to formation anilide. With an increase reaction temperature range from 111 (toluene) 170 °C (pseudo cumene), a monotonous initial rate target product is observed. In this case, depen­dence logarithm velocity obeys Arrhenius equation, activation energy Ea 66.2 kJ/mol.
 Higher-boiling n.=decane (175 °С) ortho=dichlorobenzene (180 fall out dependence, which anilide acid, compared that for pseudocumene (170 °С), decreases. The latter may be due decomposition or oxidation catalyst at such high transition P(V), does not have catalytic activity.
 interaction 3=hydro­xyl=2=naphthoic proceeds as series sequential parallel reactions which, addition 3=hydroxyl=2= naphthoic ani­lide, 3=aniline=2=naphthoic its are formed impurities.
 most acceptable solvents ortho=chlorotoluene points 146 156°C, yield up 98%. Below relatively low rate; above 156°C amount impurities increases significantly, mainly temperature, maximum 3=hydroxyl=2=naphthoic This requires additional purification, significantly complicating technological process.
 10–20% by volume nit­robenzene 3=oxy=2=naphthoic 1.25–1.42 times 146–148°C increasing solvent polarity (ε), respectively, 2.3 7.64. quantity monomers and/or mass speed separation.