METHOD OF CYCLOPENTENE SYNTHESIS Russian patent published in 1995 - IPC

FIELD: organic chemistry. SUBSTANCE: method of cyclopentene synthesis involves dicyclopentadiene depolymerization, distillation off of obtained cyclopentadiene from high-boiling impurities, hydrogenation of cyclopentadiene on the palladium-containing catalyst and isolation of prepared cyclopentene, and depolymerization is carried out in liquid phase at 160-165 C for 3-4 h, and simulateneously cyclopentadiene is distilled off from high-boiling impurities. Cyclopentadiene hydrogenation is carried out in liquid phase at 30-40 C, under pressure 0.3-0.4 MPa for 1-1.5 h of liquid flow at hydrogenation zone. Then prepared cyclopentene is isolated and purified by dimerization of nonreacted cyclopentadiene, distillation off of cyclopentene-containing fraction from dicyclopentadiene, contacting distilled off fraction with titanium tetrachloride or aluminium bromide with simultaneous rectification. Then prepared cyclopentene is contacted with triisobutyl-aluminium, and the end product is isolated by final rectification. Prepared cyclopentene has 99.5% basic substance (not less), 0.5% cyclopentene (not more), 0.0001% cyclopentadiene (not more), 0.0005% piperylenes (not more), 0.0005% isoprene (not more), 0.001% water (not more), and 0.0001% oxygen-containing impurities (not more). EFFECT: improved method of synthesis. 1 dwg, 2 tbl