| 摘要 |
Cyclopentane and/or cyclopentene is/are obtained from a partly hydrogenated benzene fore-run or C5 fraction by multistage fractional distillation to remove low- and high-boiling hydrocarbons and separate cyclopentane from cyclopentene, possibly with a catalytic hydrogenation stage to convert cyclopentene to cyclopentane. A process for the production of cyclopentane and/or cyclopentene by fractionation of a partly hydrogenated benzene fore-run or C5 fraction comprises (a) a first fractional distillation to give a first head fraction (H1) containing substances with boiling points (b.pts.) below that of cyclopentene and a first bottom fraction (B1) containing cyclopentene and hydrocarbons with higher (b.pts.) than cyclopentene, followed by (b1) fractional distillation of B1 to give cyclopentene as second head fraction (H2) and cyclopentane plus hydrocarbons with higher (b.pts.) than cyclopentane as bottom fraction (B2), followed by a third fractionation of B2 to give cyclopentane as third head fraction (H3) and higher-boiling hydrocarbons as bottom fraction (B3), or (b2) catalytic hydrogenation of B1 followed by fractional distillation to give cyclopentane as head fraction and higher-boiling hydrocarbons as bottom fraction, or (b3) fractional distillation of B1 to give hydrocarbons with higher b.pts. than cyclopentane as bottom product followed by catalytic hydrogenation of the head fraction to obtain cyclopentane from cyclopentene. Independent claims are also included for processes for the production of cyclopentane and isopentane from a similar starting material, comprising (a) fractional distillation to give a head fraction containing hydrocarbons with b.pts. below that of 2-methyl-but-2-ene (2-MB) and a bottom fraction (B1) containing 2-MB and higher-boiling hydrocarbons, followed by (b2) catalytic hydrogenation of B1 and fractional distillation to give isopentane as head fraction, cyclopentane as a side-stream and hydrocarbons with 6 or more carbon atoms as bottom product, or (b3) fractional distillation of B1 to give hydrocarbons with 6 or more carbons as bottom product (B2) and a head fraction (H3) containing cyclopentene, cyclopentane and 2-MB, followed by catalytic hydrogenation of H3 and fractional distillation to give the same fractions as in (b2).
|
