| 摘要 |
<p>Catalyst is treated with an O, O-dialkyl phosphorodithioate of Sb (I) of formula / (R-O-)2P(=S)-S- / 3Sb, where R is a 1-18C hydrocarbon gp. and I contains 6-90C. The treatment passivises the metals which have been deposited on the catalyst. In I, R is esp. 2-10C alkyl, (substd.) 5-6C cycloalkyl or (substd.) phenyl, in partic. n-propyl or octyl. I pref. contains 6-21 wt. % Sb. The amt. of I used is 1.5 (0.1-1.3) wt. %, w.r.t. catalyst. For appln., (i) the catalyst may be impregnated with a soln. of I, e.g. in cyclohexane, or (ii) 0.1-15,000 ppm I is added to the feed; after the required amt. of I has been deposited, only a small amt. of I need be added to the feed; or (iii) the deactivated catalyst is treated with I and then heated in a gas contg. O2. The catalyst is esp. an activated clay carrying small amts. of rare earths, e.g. Ce or La. The contaminated catalyst esp. contains Ni, V and/or Fe. The hydrocarbon feed may be a liquid petroleum, a fuel oil, a shale oil, a gas oil or a topped crude. Cracking is at 427-649 degrees C.</p> |
