Process for producing diesters, and diesters obtained thereby

A method for preparing at least one diester, said method comprising:

• a) a transformation reaction of the acid function of at least one hydroxycarboxylic acid, or of the ester function of at least one ester of hydroxycarboxylic acid and alcohol, into an alcohol function to obtain at least one diol, said hydroxycarboxylic acid having 11 to 25 carbon atoms,
• b) an esterification reaction of the diol via at least one saturated or unsaturated acid having 2 to 24 carbon atoms, to form at least one diester,
• the diester meeting formula (4):
• where:
• R1 is a linear or branched alkyl radical having 1 to 22 carbon atoms, or a linear or branched alkenyl radical having 2 to 22 carbon atoms,
• R2 is a divalent linear or branched alkyl or alkenyl radical having 4 to 22 carbon atoms,
• with the proviso that the total number of carbon atoms of R1 and R2 ranges from 9 to 23,
• R3 and R4 each independently are a monovalent linear or branched alkyl radical having 1 to 19 carbon atoms, or a monovalent linear or branched alkenyl radical having 1 to 18 carbon atoms.

A composition of diester(s) comprising at least one diester of formula (4):

• where:
• R1 is a linear or branched alkyl radical having 1 to 22 carbon atoms, or a linear or branched alkenyl radical having 2 to 22 carbon atoms;
• R2 is a divalent linear or branched alkyl or alkenyl radical having 4 to 22 carbon atoms,
• with the proviso that the total number of carbon atoms of R1 and R2 ranges from 9 to 23;
• R3 and R4 are each independently a monovalent linear or branched alkyl radical having 1 to 19 carbon atoms, or a monovalent linear or branched alkenyl radical having 1 to 18 carbon atoms;
• said composition of diester(s), relative to the total weight of the composition of diester(s), comprising at least 70 weight % of diesters of formula (4) which only differ from each other by the groups R3 and R4.