1,1-disubstituted ethylene process
Improved iminium based processes for the production of cyanoacrylates and methylidene malonates wherein the improvement pertains to the presence of acid chlorides and/or acid anhydrides in the reaction mix.
1. A method of producing methylidene malonates and cyanoacrylates which method comprises reacting
(A) (i) a malonic acid ester corresponding to the formula VI:
wherein R 1 is hydrogen (H) and R 2 is a C 1 to C 18 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen, halogen, or oxygen atoms or both R 1 and R 2 are independently a C 1 to C 18 hydrocarbon or heterohydrocarbon group; the latter having one or more nitrogen, halogen, or oxygen atoms or
(ii) a cyanoacetate corresponding to the formula V:
CH 2 (CN)CO 2 R 2
wherein R 2 is a C 1 to C 18 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen, halogen, or oxygen atoms, respectively, with
(B) an iminium salt corresponding to the formula
wherein R 4 and R 5 are both hydrogen (H) and R 6 and R 7 are each independently a C 1 to C 10 hydrocarbon or substituted hydrocarbon or together form a bridge whereby the nitrogen atom, R 6 and R 7 together form a ring structure; provided that neither of R 6 and R 7 is a hydrocarbon moiety comprising a tertiary carbon attached to the N atom, and X is a halogen, a carboxylate or a sultanate anion,
in the presence of
(C) from 0.2 to 1.0 equivalents based on the iminium salt (B) of (i) an acid halide of the formula R 9 C(O)X or R 9 SO 2 X, (ii) an acid anhydride of the formula R 9 C(O) 2 O or (iii) both (i) and (ii), wherein R 9 is an aliphatic or aromatic C 1 to C 18 hydrocarbon or substituted hydrocarbon and X is fluorine, chlorine, bromine or iodine.
2. The method of claim 1 wherein in the iminium salt (B) R 6 and R 7 are each independently a C 1 to C 6 alkyl or alkenyl group and X is a halogen or carboxylate anion.
3. The method of claim 1 wherein compound (A) 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 10 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 group(s) may be substituted with or contain an ether, epoxide: halo, ester, cyano, aldehyde, keto or aryl group.
4. The method of claim 3 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 17 hydrocarbon or heterohydrocarbon group, the latter having one or more nitrogen, halogen, or oxygen atoms, and n is an integer of from 1 to 5.
5. The method of claim 1 wherein compound (A) is a cyanoactetate (ii) of formula V and R 2 is a C 1 to C 6 hydrocarbon.
6. The method of claim 1 wherein the equivalent weight of iminium salt to malonic acid ester is from 1:1 to 10:1.
7. The method of claim 1 wherein, an acid halide is present and is an acid chloride.
8. The method of claim 1 wherein the acid halide and/or acid anhydride are selected from the group consisting of acetyl chloride, propionyl chloride, isobutyryl chloride, trimethylacetyl chloride, acetic anhydride, propionic anhydride, isobutyric anhydride, trimethylacetic anhydride, trifluoro anhydride, sulfonic acid anhydride, benzoyl chloride, chloroacetylchloride.
9. The method of claim 1 wherein the reaction is conducted in the presence of a non-polar solvent.
10. The method of claim 9 wherein the non-polar solvent is selected from the group consisting of toluene, benzene, diethylether, chloroform, hexane, cyclohexane and carbontetrachloride.