| abstract |
The present invention relates to a process for preparing cyclohexane from methylcyclopentane (MCP) and benzene. In the present invention, MCP and benzene are mixed with a hydrocarbon mixture also containing at least one compound selected from dimethyl pentane (DMP), optionally cyclohexane and optionally non-cyclic C 5 -C 6 alkane and cyclopentane (low boiling point material) (HM1). First, benzene is reacted in a hydrogenation step to provide cyclohexane (present in the hydrocarbon mixture (HM2)) while MCP is isomerized to cyclohexane in the presence of a catalyst, preferably an acidic ionic liquid. After the hydrogenation but prior to the isomerization, dimethyl pentane (DMP) is removed and the cyclohexane initially present in the hydrocarbon mixture (HM2) is removed with DMP. This pre-isomerized cyclohexane can be removed again at the downstream stage of the rectification and can be isolated and / or returned to the cyclohexane manufacturing process. If the hydrocarbon mixture (HM1) contains a low boiling point material, it can be removed between DMP removal and MCP isomerization. There is an isolation of cyclohexane after isomerization, and there is an optional recycle of the isomerized MCP and any low boiling point material. The hydrocarbon mixture (HM1) preferably comprises cyclohexane and / or a low boiling point material, so that removal of the low boiling point material between the DMP elimination prior to isomerization is a desirable operation. Further removal of the DMP from the cyclohexane is also preferred and is recovered by isolating the cyclohexane fraction resulting from the benzene hydrogenation and possibly forming part of the starting mixture (HM1). |