Synthesis of urethanes and polyurethanes catalysed by carbenes
AssigneesVencorex Frence, Centre National de la Recherche Scientifique (CNRS)
InventorsGerard Mignani, Mathias Destarac, Daniel Taton, Yves Gnanou, Antoine Baceiredo, Tsuyoshi Kato, Fabien Bonnette, Gopakumar Sivasankarapillai
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Abstract
The present invention relates to a process for preparing a compound comprising at least a urethane group —HN—C(═O)—O, said process comprising a step (E) in which a compound (I) comprising at least an isocyanate functional group —N═C═O is reacted with an organic compound (II) carrying at least a hydroxyl group —OH, said reaction being carried out in a presence of a carbene (III) used as a catalyst.
Claims19
A process for preparing a compound comprising at least a urethane group —HN—C(═O)—O, said process comprising a step (E) wherein a compound (I) carrying two isocyanate functional groups —N═C═O is reacted with an organic compound (II) carrying two hydroxyl groups —OH, this reaction being carried out in the presence of a heterocyclic carbene (III) catalyst, the molar ratio of carbene (III) to isocyanate functional groups being 0.0001 to 0.05, and at 10 to 80° C.
The process of claim 7, wherein the carbene (III) has one of the following general formulae (III-1.1) or (III-1.1′):
- where:
- Y is a heteroatom selected from N, S, P, Si and O,
- ny and RY are as defined in claim 12;
- and
- RI denotes a hydrocarbon chain which is linear or branched, optionally cyclised in part or completely, and optionally substituted,
- A denotes a nitrogen atom or a CRIIa group;
- B denotes a nitrogen atom or a CRIIIa group;
- RII and RIII, and optionally RIIa and RIIIa which may the same or different, each denote a hydrogen atom or a hydrocarbon chain which is linear or branched, optionally cyclised in part or completely, and optionally substituted.
The process of claim 1, wherein the carbene (III) is formed in situ in the medium of step (E) from at least a precursor (PC) of said carbene, said precursor being:
- a carbene in dimerised form which is split into two carbenes in situ by thermal activation, said dimerised carbene advantageously corresponding to the following formula (PCD):
- wherein X, Y, nx, ny, RX and RY are as defined in claim 12;
- or
- an imidazolium salt, which forms a carbene in situ by reaction with a base, said imidazolium salt advantageously corresponding to one of the following formulae (PCS) or (PCS′):
- where:
- B, RI, RII, RIII and RIV are as defined in claim 15;
- and
- An− is an anion derived from a Brönsted acid, advantageously a carboxylate, sulfate, hydrogen sulfate, sulfonate, phosphate, hydrogenphosphate, halide, perchlorate or borate anion;
- carbene and alcohol complex which releases the carbene in situ when thermally treated.
Dependencies are inferred from the claim text.