1,1-disubstituted ethylene process
Process for the production of methylidene malonates and cyanoacrylates employing in-situ formed iminium salts derived from acid halides and/or acid anhydrides and N,N,N′,N′-tetra hydrocarbyl diaminoalkanes, the acid halides and/or acid anhydrides being present in a molar excess relative to the diaminoalkanes, as co-reactants with select malonic acid esters and cyanoacetates, respectively.
1. A method of producing methylidene malonates and cyanoacrylates which method comprises (1) reacting (A) an N,N,N′,N′-tetra C 1 to C 6 hydrocarbyl diaminomethane with (B) from a 0.2 to a 10 molar equivalent excess of an acid halide according to formulae R 9 C(O)X or R 9 SO 2 X and/or an acid anhydride according to formula (R 9 C(O)) 2 O where R 9 is a C 1 to C 6 hydrocarbon or substituted hydrocarbon and X is fluorine, chlorine, bromine or iodine, to form an in-situ reaction product comprising an iminium compound according to the Formula II:
wherein R 4 and R 5 are both H and R 6 and R 7 are each independently a C 1 to C 6 hydrocarbon or substituted hydrocarbon or together form a bridge whereby the nitrogen atom, R 6 and R 7 together form a ring structure, and X − is an X anion or a carboxylate anion, and
(2) reacting the in-situ reaction product which includes the excess acid halide and/or acid anhydride with (C)
(i) a malonic acid ester corresponding to the formula VI:
wherein either (A) R 1 is hydrogen (H) and R 2 is a C 1 to C 8 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen or oxygen atoms or (B) both R 1 and R 2 are independently a C 1 to C 8 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen or oxygen atoms or
(ii) a cyanoacetate corresponding to the formula V:
CH 2 (CN)CO 2 R 2 V
wherein R 2 is a C 1 to C 8 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen or oxygen atoms.
2. The method of claim 1 wherein R 9 is a C 1 to C 6 alkyl or alkenyl group.
3. The method of claim 1 wherein the molar equivalent excess of acid halide and/or acid anhydride is from 0.2 to 5.
4. The method of claim 1 wherein the molar equivalent excess of acid halide and/or acid anhydride is from 0.5 to 2.
5. The method of claim 1 wherein neither of R 6 and R 7 is a hydrocarbon or heterohydrocarbon moiety comprising a tertiary carbon attached to the N atom.
6. The method of claim 1 wherein compound (C) is a malonic acid ester (i) of formula VI and one or both of R 1 and R 2 are independently, a C 1 to C 8 linear or branched alkyl group, a C 3 to C 6 alicyclic group, a C 2 to C 6 alkenyl group, or a C 2 to C 6 alkynyl group, which groups may be substituted with or contain an ether or an ester group.
7. The method of claim 6 wherein neither of R 6 and R 7 is a hydrocarbon or heterohydrocarbon moiety comprising a tertiary carbon attached to the N atom.
8. The method of claim 1 wherein at least one of R 1 and R 2 is of the formula:
—(CH 2 ) n —COOR 3
wherein R 3 is a C 1 to C 6 hydrocarbon or heterohydrocarbon group, the latter having one or more oxygen atoms, and n is an integer of from 1 to 5.
9. The method of claim 1 wherein the malonic acid ester is a monoester wherein R 1 is H.
10. The method of claim 1 wherein the malonic acid ester is a diester wherein neither of R 1 or R 2 is H.
11. The method of claim 1 wherein compound (C) is a cyanoacetate (ii) of formula V and R 2 is a C 1 to C 6 hydrocarbon.
12. The method of claim 1 wherein the equivalent weight of iminium salt to malonic acid ester is from 1:1 to 10:1.
13. The method of claim 1 wherein the equivalent weight of iminium salt to malonic acid ester is from 1:1 to 6:1.
14. The method of claim 1 wherein an acid halide is present and is an acid chloride.
15. The method of claim 14 wherein the acid chloride is selected from the group consisting of acetyl chloride, propionyl chloride, isobutyryl chloride, trimethylacetyl chloride, benzoyl chloride, and chloroacetyl chloride.
16. The method of claim 1 wherein an acid anhydride is present.
17. The method of claim 16 wherein the acid anhydride is selected from the group consisting of acetic anhydride, propionic anhydride, isobutyric anhydride, trimethylacetic anhydride, trifluoroacetic anhydride, and sulfonic acid anhydride.
18. The method of claim 1 wherein the reaction is conducted in the presence of a non-polar solvent.
19. The method of claim 18 wherein the non-polar solvent is selected from the group consisting of toluene, benzene, diethylether, chloroform, hexane, cyclohexane and carbontetrachloride.
20. The method of claim 1 further comprising a step (3) wherein a non-polar solvent solution of the 1,1-disubstituted ethylenic reaction product of step (2) is treated with an acidic, activated alumina.
21. The method of claim 1 wherein R 2 is of the formula:
—(CH 2 )—COOR 3
and R 1 and R 3 are the same or different and represent a C 1 to C 3 lower alkyl.