Pyrolysis of Aryl Glycolic Acids. II. The Thermochromic Product Derived from Anisilic Acid^1,2

Thermochromism.

“…Davis and Perrin (21) added that kinetic evidence showed that the maximum concentration of free radicals present in disulfides was about 10~7 mole per liter, Cold solution is blue, hot is blue-green (13 s) Cold solution is blue, hot is blue-green (13 s) v. Miscellaneous Compounds Schonberg, Mustafa and Asker (116) put to the test the theory that overcrowded molecules which could achieve a greater degree of planarity by increase in thermal energy might be thermochromic, and reported discovery of thermochromism in eight compounds; rubrene, tetracyclone, acecyclone, 4-triphenyl-l,2-qui- That the nitro group can sometimes confer thermochromism on a compound not otherwise thermochromic was again noted when Bottle and Gilbert (12) reported on 3,5-dinitrosalicylic acid as mildly thermochromic. The thermochromism of o-hydroxy-p,p ',p ",p'' '-tetramethoxytetraphenylsuccinic acid bislactone was established by paramagnetic measurements and molecular weight determinations to be due to free radicals formed by dissociation (143).…”