Synthesis of dithioester chain transfer agents and use of bis(thioacyl) disulfides or dithioesters as chain transfer agents
AssigneesE.I. DuPont Nemours and Company, Commonwealth Scientific and Industrial Research Organisation
InventorsEnzio Rizzardo, San Hoa Thang, Graeme Moad
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Abstract
This invention relates to the synthesis of dithiocarboxylic acid esters by reaction of bis(thioacyl) disulphides, thioacetals or vinylidane bis(thioether) with free-radicals (optionally in the presence of monomers). The invention also relates to processes for the synthesis of polymers utilising these dithioesters as polymerisation regulators (chain transfer agents) or to the use of bis(thioacyl) disulphides to generate dithioester chain transfer agents in situ.
Claims25
A process for the synthesis of a dithioester of formula I:
- where R is derived from a free radical R. and is selected from the group consisting of optionally substituted alkyl;
- optionally substituted, saturated, unsaturated or aromatic carbocyclic rings;
- optionally substituted, saturated, unsaturated or aromatic heterocyclic rings;
- optionally substituted alkylthio, optionally substituted arylthio;
- optionally substituted alkoxy, optionally substituted dialkylamino;
- organometallic species;
- and polymer chains;
- R. is a free radical leaving group;
- U is independently selected from the group consisting of hydrogen;
- halogen;
- and C1-4 alkyl optionally substituted with one or more substituents independently selected from the group consisting of hydroxy, carboxy, acyloxy, OR″, O2CR″ and CO2R″;
- V is independently selected from the group consisting of hydrogen, halogen, R″, CO2H, CO2R″, COR″, CN, CONH2, CONHR″, CONR2″, O2CR″ and OR″;
- Z is selected from the group consisting of hydrogen, chlorine, optionally substituted alkyl, optionally substituted aryl, optionally substituted alkylthio, optionally substituted alkoxycarbonyl, —CO2R″, —CO2H, —O2CR″, —CONR2″, cyano, [—P(═O)(OR″2], and [—P(═O)R″2];
- R″ is independently selected from the group consisting of optionally substituted C1-18 alkyl, optionally substituted C2-18 alkenyl, optionally substituted aryl, optionally substituted heterocyclyl, optionally substituted aralkyl, optionally substituted alkaryl, wherein said acyl, acyloxy, carboxy (and salts), sulphonic acid (and salts), alkoxycarbonyl, aryloxycarbonyl, isocyanato, cyano, silyl, halo and dialkylamino;
- and n is 0 or a positive integer,
- which process includes contacting a disulphide of the Formula II:
- with
- (i) in the case of n=0, a free radical of the formula R., or
- (ii) in the case of n>0, a free radical of the formula R. and at least one monomer of the formula III
A polymer prepared in accordance with claim.
Dependencies are inferred from the claim text.