Metathesis catalysts
View Patent ↗The present invention relates to supported catalysts based on Re 2 O 7 /(—Al 2 O 3 for use in the preparation of cycloalkadienes in a metathesis reaction, a process for preparing cycloalkadienes in the presence of these supported catalysts and also the use of the resulting cycloalkadienes for preparing fragrances.
1. A process for preparing cycloalkadienes by a metathesis reaction comprising the steps of:
(1) using a supported catalyst comprising γ-Al 2 O 3 as support material, and Re 2 O 7 , wherein the pore volume of the supported catalyst is greater than or equal 0.6 cm 3 /g; and
(2) passing cycloalkamonoenes, cyclo-polyenes, acyclic polyenes or mixtures thereof in the liquid phase through said supported catalyst.
2. The process according to claim 1 , wherein the pore volume of the supported catalyst is in the range from 0.7 to 1.3 cm 3 /g.
3. The process according to claim 1 , wherein the supported catalyst is used as shaped bodies.
4. The process according to claim 1 , wherein the supported catalyst has an Re 2 O 7 content in the range from 1 to 12% by weight.
5. The process according to claim 1 , wherein the supported catalyst comprises:
(a) γ-Al 2 O 3 as support material;
(b) from 1 to 12% by weight of Re 2 O 7 ;
(c) from 0 to 30% by weight of tin; and at least one of the following constituents:
(d) from 0.2 to 3% by weight of cesium; and
(e) from 0.3 to 3% by weight of phosphorus.