Montedison S.p.a.

Istituto Donegani S.p.a.

Giuseppe Salerno

Gian P Chiusoli

Luciano Pallini

William Giroldini

This invention relates to a process for preparing dienoic acids. In particular, the present invention relates to a catalytic process for preparing octadienoic acids from 3-butenoic acids and butadiene. More particularly the present invention is directed to the preparation of octadienoic acids haing the two double bonds in position 3,6 and 2,6 in respect of the carboxylic carbon, starting from 3-butenoic acids and butadiene in the presence of complex catalysts of Rhodium or of Nickel.

Process for preparing dienoic acids

There is disclosed and claimed a process for preparing aryl- and heteroarylhexadienoic acids which is characterized in that an aryl- or heteroarylacetylene having the formula: R--C.tbd.CH, wherein R is an aryl or heteroaryl group, optionally substituted and having in the aggregate up to 20 carbon atoms, is reacted with 3-butenoic acid CH.sub.2 .dbd.CH--CH.sub.2 --COOH, in an alcoholic medium, at temperatures maintained between 50.degree. C. and 120.degree. C., approximately, in the presence of a catalyst selected from among the phosphinic complexes of rhodium having the formulas: III, Rh(PR'.sub.3).sub.n L.sub.m X associated with alkaline salts of carboxylic acids having up to 4 carbon atoms, and IV, Rh(PR'.sub.3).sub.n L.sub.p.sup.+ Y.sup.-, wherein R' is a hydrocarbyl group having up to 12 carbon atoms; 'L' is a linear or cyclic olefin selected from among the olefins having from 2 to 10 carbon atoms and the chelating olefins having from 6 to 8 carbon atoms, n is an integer from 1 to 3, m is an integer from 0 to 2 and such that n+m=2 or 3, and p is an integer from 0 to 3 and such that n+p=3 or 4; X is an anion selected from among the haloid anions, preferably the hydrochloric anion, and the anions of carboxylic acids having up to 4 carbon atoms and Y is a sparingly coordinating anion, preferably selected from PF.sub.6.sup.- and BF.sub.4.sup.-. The compounds obtained are used as intermediates for organic syntheses, with particular regard to the so-called 'fine chemicals' such as, for example, additives for polymers and paints, plasticizers, and the like.

Process for preparing aryl- or heteroarylhexadienoic acids

Dienoic acids are prepared by reaction of salts of 3-butenoic acid and vinyl halides, in the presence of catalysts which are phosphinic complexes of rhodium or nickel.

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Parma, Italy

Giuseppe Salerno