Alpha-cyanoacrylate ester synthesis
AssigneeHenkel Ireland Limited
InventorStephen Hynes
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Abstract
The high temperatures required for cracking the cyanoacrylate oligomers, produced by the Knovenagel condensation of formaldehyde and a cyanoacetate, limit the synthetic diversity and the number of different side chains that can be incorporated into a cyanoacrylate prepared using this method. Accordingly, the diversity of cyanoacrylate monomers prepared industrially is quite limited. Disclosed herein is a method for the preparation of alpha-Cyanoacrylate ester monomers from a variety of phosphonium and ammonium alpha-cyanoacrylate salts. The phosphonium and ammonium alpha-cyanoacrylate salts are of the general formula:
Claims24
A method of preparing an alpha-cyanoacrylate ester monomer comprising the step of:
- reacting an alpha-cyanoacrylate salt of the general formula:
- with a compound of the general formula R7—X, wherein:
- Z is N or P;
- R1 and R2 are the same or different and are selected from H, C1-C20 aliphatic, C3-C20 cycloaliphatic, C5-C20 aromatic, C3-C20 heteroaromatic and combinations thereof;
- R3, R4, R5 and R6 are the same or different and are selected from H, C1-C20 aliphatic, C3-C20 cycloaliphatic, C5-C20 aromatic, C3-C20 heteroaromatic and combinations thereof, such that at least two of R3, R4, R5 and R6 are not H;
- or
- any two of R3, R4, R5 and R6 may together with Z define a C5-C20 aliphatic heterocycle;
- or
- any three of R3, R4, R5 and R6 may together with Z define a C5-C20 aliphatic heterocycle;
- R7 is selected from the group consisting of C1-C20 aliphatic, C3-C20 cycloaliphatic and combinations thereof;
- and
- X is a leaving group, wherein the conjugate acid HX of the leaving group X has a pKa of −2 or less.
Use of an alpha-cyanoacrylate salt of the formula:
- in the synthesis of alpha-cyanoacrylate ester monomers, wherein:
- Z is N or P;
- R1 and R2 are the same or different and are selected from H, C1-C20 aliphatic, C3-C20 cycloaliphatic, C5-C20 aromatic, C3-C20 heteroaromatic and combinations thereof;
- R3, R4, R5 and R6 are the same or different and are selected from H, C1-C20 aliphatic, C3-C20 cycloaliphatic, C5-C20 aromatic, C3-C20 heteroaromatic and combinations thereof, such that at least two of R3, R4, R5 and R6 are not H;
- or
- any two of R3, R4, R5 and R6 may together with Z define a C5-C20 aliphatic heterocycle;
- or
- any three of R3, R4, R5 and R6 may together with Z define a C5-C20 aliphatic heterocycle.
Dependencies are inferred from the claim text.