| 摘要 |
Petroleum waxes are converted to high viscosity index lubricants by a hydroisomerization process in which the wax feed is subjected to hydroisomerization over a low acidity zeolite isomerization catalyst which effects a preferential isomerization on the paraffin components in the feed to less waxy, high V.I. isoparaffins. The hydroisomerization is operated at high pressure, at least 1000 psig hydrogen partial pressure (reactor inlet) using a zeolite catalyst, preferably a noble metal containing zeolite beta catalyst which contains boron as a framework component of the zeolite to give a low alpha value, typically below 10. The hydroisomerization is carried out at a 650.degree.F+ conversion in the range of 10 to 40 weight percent of the feed. A final dewaxing step to target pour point may be used with relatively low loss, typically no more than 15 weight percent, during this dewaxing. The final products typically have V.I. values in excess of 125 and usually in the range of 140 to 155 and are characterized by exceptional stability.
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