Difunctional biphenyl compounds, preparation, and uses

A process for preparing a compound of formula (I):

• wherein:
• Alk is a linear or branched alkyl group having from 1 to 6 carbon atoms,
• Alk′ is a linear or branched alkyl group having from 1 to 6 carbon atoms, and
• R is selected from —CH2—NH2, —N═C═O and —NH2;
• which process comprises:
• a) providing a product selected from the group consisting of vanillin, analogues of vanillin having an —O—(C2-C6)alkyl group in the 3-position, esters of vanillin and analogues of said esters having an —O—(C2-C6)alkyl group in the 3-position;
• b) dimerizing said product to obtain a dimer,
• c) treating said dimer obtained to convert its phenolic —OH functions to —OAlk′ alkoxy functions and either its aldehyde functions to aminomethyl functions (—CH2—NH2) or its ester functions to isocyanate (—N═C═O) or amino (—NH2) functions.

A method of obtaining a thermoset resin, which comprises reacting a thermosetting resin with a compound of formula (I):

• wherein:
• Alk is a linear or branched alkyl group having from 1 to 6 carbon atoms,
• Alk′ is a linear or branched alkyl group having from 1 to 6 carbon atoms, and
• R is selected from —CH2—NH2, —N═C═O and —NH2.