Process for producing 5-hydroxymethylfurfural in the presence of an organic dehydration catalyst and a chloride source

A process for converting a feedstock comprising at least one sugar into 5-hydroxymethylfurfural, which comprises bringing said feedstock into contact with at least one organic dehydration catalyst independently chosen from homogeneous and heterogeneous organic Brønsted acids, and at least one chloride source in the presence of at least one aprotic polar solvent, at a temperature of between 30° C. and 200° C. and a pressure of between 0.1 and 10 MPa,

• wherein the chloride source is:
• an organic cation of the guanidium family chosen from compounds of formula (IIIb)
• wherein the groups R5 to R10, which may be identical or different, are independently chosen from alkyl groups comprising between 1 and 20 carbon atoms, and aryl groups comprising between 5 and 20 carbon atoms, or
• an organic cation of the phosphonium family chosen from compounds of formula (IIIc)
• wherein R11 to R14, which may be identical or different, are independently chosen from
• alkyl groups, comprising between 1 and 20 carbon atoms,
• aryl groups, comprising between 5 and 20 carbon atoms, and
• phosphazene groups of general formula
• wherein R15 is an alkyl group comprising from 1 to 10 carbon atoms, and q is an integer between 0 and 10.