Process for the preparation of antioxidant amides

An improved process for the synthesis of a .alpha.,.beta. unsaturated aryl amides comprising reacting an organic acid having general formula I:

• ##STR5## wherein R.sub.1 is selected from the group consisting of hydrogen, methyl or phenyl radicals;
• with an aryl amine selected from one of the following structural formulae:
• ##STR6## wherein R.sub.2 and R.sub.3 are the same or different alkyl radicals selected from the group consisting of isopropyl, secondary butyl, tert.-butyl, tert.-pentyl or tert.-hexyl;
• R.sub.4 and R.sub.5 are the same or different radicals selected from the group consisting of hydrogen, methyl or ethyl;
• and R.sub.6 is selected from a phenyl radical or an alkyl substituted phenyl radical with one to three same or different alkyl substituents selected from either methyl or ethyl radicals;
• to produce a hydroxy aryl amide having one of the following structural formulae:
• ##STR7## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are defined as above, and (B) dehydrating, through use of concentrated sulfuric acid at a temperature of 98.degree.-110.degree. C. in at least a 1 to 1 molar ratio, the hydroxy aryl amide to form an .alpha., .beta. unsaturated amide having one of the following structural formulae:
• ##STR8## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are defined as above.