| 摘要 |
PURPOSE:To advantageously prepare a refrigerator oil having excellent low- temp. characteristics, by hydrotreating a deasphalted oil derived from a paraffin base crude oil or a mixed base crude oil, dewaxing the deasphalted oil, conducting solvent extraction of the dewaxed oil to obtain an extract oil, and treating the extract oil with an adsorbent. CONSTITUTION:A lubricating oil fraction collected from a paraffin base crude oil or a mixed base crude oil, or a deasphalted oil obtd. by deasphalting the aforesaid crude oil is hydrotreated or extracted and then hydrotreated (first step). The hydrotreated oil is dewaxed (second step). The dewaxed oil is extracted with a solvent having a selective affinity for an arom. hydrocarbon (e.g., furfural or phenol) to collect an extract oil having a fluid point of -30 deg.C or below and an n-d-M ring analysis value (%) CA of 10 or more (third step). This extract oil is adsorbed on a solid adsorbent (e.g., activated clay) (fourth step). Thus it is possible to advantageously prepare a refrigerator oil having excellent low temp. characteristics which has been prepared in the art with great difficulty. |
