Process of extraction of a platinum group metal or gold from organic compositions with surfactants

A process of extracting at least one metal chosen from the platinum group metals and gold from a liquid composition to an aqueous solution, said liquid composition comprising:

• at least one metal chosen from the platinum group metals and gold, and
• an organic solvent, said organic solvent being water immiscible,
• wherein the process further comprises contacting the liquid composition with a surfactant comprising:
• a hydrophobic central core of valence m equal to 1, 2 or 3;
• when m=1, a hydrophilic group G of the following formula, attached to the central core:
• wherein:
• R7 is selected from H, C1-C6 alkyl and CH2OR10;
• R10 is H or a monosaccharide selected from glucose, galactose, mannose;
• w is an integer from 1 to 30;
• when m=2 or 3, the surfactant being then a dendrimer of generation n,
• generation chains attached to the central core and branching around the core;
• and
• an hydrophilic terminal group at the end of each generation chain;
• wherein
• n is an integer from 0 to 12;
• the hydrophilic terminal group comprises:
• a mono-, oligo- or polysaccharide residue,
• a cyclodextrin residue,
• a polyethylene glycol (PEG) residue,
• a peptide residue,
• a tris(hydroxymethyl)aminoethane (Tris), or
• a 2-amino-2-methylpropane-1,3-diol;
• the central core being:
• when m=1, a -L′-W′ group,
• wherein:
• W′ is RF or a group selected from W′1, W′2 or W′3:
• RF is a C4-C10 perfluoroalkyl or a C1-C24 alkyl group,
• RH is a C1-C24 alkyl group,
• p is 0, 1, 2, 3 or 4;
• q is 0, 1, 2, 3 or 4;
• L′ is a linear or branched C1-C12 alkylene group, optionally interrupted by one or more groups Y′;
• Y′ at each occurrence is chosen from —OC(═O)—, —C(═O)O—, —O—C(═O)—NH—, —NH—C(═O)—O—, —OC(═O)—O—, —NHC(═O)—, —C(═O)—NH, —NHC(═O)NH—, —NHC(═O)O—, —O—C(═O)—NH—, —NH—, —O— or Y at each occurrence is chosen from —S—, —OC(═O)—, —C(═O)O—, —O—C(═O)—NH—, —NH—C(═O)—O—, —OC(═O)—O—, —NHC(═O)—, —C(═O)—NH, —NHC(═O)NH—, —NHC(═O)O—, —O—C(═O)—NH—, —NH— or —O—;
• when m=2 or 3, a group of formula (Ia) or (Ib):
• wherein:
• W is RF or a group selected from W0, W1, W2 or W3:
• RF is a C4-C10 perfluoroalkyl or a C1-C24 alkyl group,
• RH is a C1-C24 alkyl group,
• p is 0, 1, 2, 3 or 4;
• q is 0, 1, 2, 3 or 4;
• L is a linear or branched C1-C12 alkylene group, optionally interrupted by one or more —O—, —S—,
• Z is C(═O)NH or NHC(═O),
• R is a C1-C6 alkyl group, and
• e is at each occurrence independently selected from 0, 1, 2, 3 or 4.

A micelle or an aqueous solution comprising at least one metal chosen from the platinum group metals and gold and a surfactant as comprising:

• a hydrophobic central core of valence m equal to 1, 2 or 3;
• when m=1, a hydrophilic group G of the following formula, attached to the central core:
• wherein:
• R7 is selected from H, C1-C6 alkyl and CH2OR10;
• R10 is H or a monosaccharide selected from glucose, galactose, mannose;
• w is an integer from 1 to 30;
• when m=2 or 3, the surfactant being then a dendrimer of generation n,
• generation chains attached to the central core and branching around the core;
• and
• an hydrophilic terminal group at the end of each generation chain;
• wherein
• n is an integer from 0 to 12;
• the hydrophilic terminal group comprises:
• a mono-, oligo- or polysaccharide residue,
• a cyclodextrin residue,
• a polyethylene glycol (PEG) residue,
• a peptide residue,
• a tris(hydroxymethyl)aminoethane (Tris), or
• a 2-amino-2-methylpropane-1,3-diol;
• the central core being:
• when m=1, a -L′-W′ group,
• wherein:
• W′ is RF or a group selected from W′1, W′2 or W′3:
• RF is a C4-C10 perfluoroalkyl or a C1-C24 alkyl group,
• RH is a C1-C24 alkyl group,
• p is 0, 1, 2, 3 or 4;
• q is 0, 1, 2, 3 or 4;
• L′ is a linear or branched C1-C12 alkylene group, optionally interrupted by one or more groups Y′;
• Y′ at each occurrence is chosen from —OC(═O)—, —C(═O)O—, —O—C(═O)—NH—, —NH—C(═O)—O—, —OC(═O)—O—, —NHC(═O)—, —C(═O)—NH, —NHC(═O)NH—, —NHC(═O)O—, —O—C(═O)—NH—, —NH—, —O— or Y at each occurrence is chosen from —S—, —OC(═O)—, —C(═O)O—, —O—C(═O)—NH—, —NH—C(═O)—O—, —OC(═O)—O—, —NHC(═O)—, —C(═O)—NH, —NHC(═O)NH—, —NHC(═O)O—, —O—C(═O)—NH—, —NH— or —O—;
• when m=2 or 3, a group of formula (Ia) or (Ib):
• wherein:
• W is RF or a group selected from W0, W1, W2 or W3:
• RF is a C4-C10 perfluoroalkyl or a C1-C24 alkyl group,
• RH is a C1-C24 alkyl group,
• p is 0, 1, 2, 3 or 4;
• q is 0, 1, 2, 3 or 4;
• L is a linear or branched C1-C12 alkylene group, optionally interrupted by one or more —O—, —S—,
• Z is C(═O)NH or NHC(═O),
• R is a C1-C6 alkyl group, and
• e is at each occurrence independently selected from 0, 1, 2, 3 or 4.