Method for preparing dithiocarbamates in particular from polyols of the glycerol type

A method for the preparation of a glycerol dithiocarbamate (GDTC) of formula

• R1—C(OH)—CH2—S—C—(S)—NR2R3 (I)
• or
• R′1R′2—N—C(S)—S—CH2—CH(OH)—CH2—S—C(S)—NR2R3 (I′)
• or
• R2R3—N—C(S)—S—CH2—CH(OH)—CH2—O—CH2—CH(OH)—CH2—S—C(S)—NR2R3 (I″)
• in which
• R1 represents H;
• a linear or branched C1-C22 alkyl radical or a C3-C16 cyclo-alkyl radical optionally substituted with one or more hydroxy, —O-alkyl, thiohydroxy or —S-alkyl groups, the chain of the alkyl radical optionally being interrupted by one or more O, N or S heteroatoms;
• a linear or branched C2-C22 alkenyl radical mono- or poly-unsaturated;
• a C2-C6 alkynyl radical;
• a C6-C10 aryl radical;
• or a C7 to C22 arylalkyl radical;
• and
• R2 and R3, independently of each other, represent H;
• a linear or branched C1-C22 alkyl radical or a C3-C16 cyclo-alkyl radical optionally substituted with one or more hydroxy, —O-alkyl, thiohydroxy or —S-alkyl groups, the chain of the alkyl radical optionally being interrupted by one or more O, N or S heteroatoms;
• a linear or branched, mono- or poly-unsaturated C2-C22 alkenyl radical;
• a C2-C6 alkynyl radical;
• a C6-C16 aryl radical;
• or a C7 to C22 arylalkyl radical;
• or R2 and R3 together with the nitrogen atom to which they are bonded form a cycloamino group;
• R′1 and R′2 have the same meanings as R2 and R3,
• wherein said method comprises
• implementing a reaction medium with a carbon disulphide CS2 and a primary or secondary amine NHR2R3 wherein R2 and R3 are as defined above,
• said reaction medium comprising
• (a) a glycerol type polyol of formula
• R1—CH(OH)—CH2OH (II)
• in which R1 has the same meanings as above and a carbonate selected from the group consisting of diethyl carbonate, dimethyl carbonate, ethylene carbonate and propylene carbonate in the presence of a basic catalyst, or
• (b) a cyclic carbonate comprising five ring members having the following formula (IV):
• wherein R1 has the same meanings as above, or
• (c) a cyclic carbonate comprising five ring members of formula
• in which R′1 and R′2, independently of each other, represent H;
• a linear or branched C1-C22 alkyl radical or a C3-C16 cyclo-alkyl radical optionally substituted with one or more hydroxy, —O-alkyl, thiohydroxy or —S-alkyl groups, the chain of the alkyl radical optionally being interrupted by one or more O, N or S heteroatoms;
• a linear or branched, mono- or poly-unsaturated C2-C22 alkenyl radical;
• a C2-C6 alkynyl radical;
• a C6-C16 aryl radical;
• or a C7 to C22 arylalkyl radical;
• or R′1 and R′2 together with the nitrogen atom to which they are bonded form a cycloamino group;
• or
• (d) a cyclic polycarbonate comprising five ring members;
• and recovering the formed GDTC.