Ethylene → Styrenesulfonic acid

Participants

Reaction Steps

EP-A 0 508 264 relates to a process for preparing arylolefins by reaction of aryldiazonium salts with olefins in the presence of a palladium catalyst. Although the use of heterogeneous palladium catalysts is mentioned (cf. EP-A 0 508 264 A1 page 4, lines 2 to 3), it is experimentally verified in only one case, namely the reaction of aniline-2-sulfonic acid with ethylene to give styrene-2-sulfonic acid (Example 6). However, as shown by comparison with Example 4 carried out using Pd(OAc)2, the yield decreases considerably when using a supported palladium catalyst (10% Pd on carbon) (Example 4: 87% yield; Example 7: 74% yield). In both examples the reaction is carried out with the addition of a base which is used in excess based on the aniline-2-sulfonic acid. As the experimental finding proves (see comparative experiment in the experimental section), the method practiced in the examples of EP-A 0 508 264, of preparing the aryldiazonium salts in situ and subsequently processing further, cannot be generally applied to the use of palladium-containing supported catalysts. The comparative experiment verifies that the desired aromatic olefin is not formed even in small amounts.

Provenance & Evidence