A method for improving the cetane number of an aromatic hydrocarbon oil such as FCC light cycle oil and thereby increase its value as a blending stock for diesel fuel or heating oil. In one embodiment, the FCC light cycle oil is alkylated in the presence of a solid acidic catalyst and with a linear mono-olefin having a chain length of at least five carbon atoms. In another embodiment, the light cycle oil is alkylated with an olefin having three to nine carbon atoms or a mixture thereof and with ZSM-20 as catalyst to decrease the frequency of catalyst regeneration.

Silica-aluminas having a sodium content less than about 0.1 weight percent show increased stability when used as a catalyst for the alkylation of aromatic compounds. Where such silica-aluminas are used as the catalyst in detergent alkylation their increased stability permits continuous alkylation to be performed at lower temperatures, as a result of which the detergent alkylate product shows an incrementally higher linearity. Fluorided silica-aluminas having a sodium content of under 0.05 weight percent are particularly advantageous.

This invention relates to a novel zeolite which has the crystal structure of zeolite beta. The novel zeolite SN-beta has a unique infrared absorbance spectrum, shows enhanced activity for transalkylation of di-isopropyl-benzene and shows less deactivation for cumene synthesis. The zeolite beta is prepared by taking an as-synthesized zeolite beta, steam treating it and then ammonium ion treating it to give a zeolite SN-beta with enhanced catalytic properties.

A fluorided silica-alumina catalyst, particularly one with a silica:alumina ratio in the range of 1:1-9:1 containing from 1 to 6 weight percent fluoride, is particularly effective in the liquid phase alkylation of benzene by linear olefins to produce linear alkyl benzenes at temperatures no greater than 140.degree. C. These catalysts also are effective in the liquid phase alkylation of alkylatable aromatics generally with a variety of alkylating agents, including olefins, alcohols, and alkyl halides.

Process for the alkylation of aromatic substrates with a C.sub.2 -C.sub.4 alkylating agent over an alkylation catalyst comprising zeolite omega at moderate temperature conditions and under pressure to provide liquid phase conditions. The liquid phase alkylation process is carried out using a plurality of series connected reaction stages operated at an average temperature of no more than 300.degree. C. with the interstage injection of the C.sub.2 -C.sub.4 alkylating agent in a manner to maintain at least 2 mole percent of alkylating agent solubilized in the aromatic substrate. The reaction stages of a multistage system temperature and pressure conditions effective to cause are operated at a pressure above the vapor pressure of the aromatic substrate and below the vapor pressure of the alkylating agent at the alkylation reaction conditions. The aromatic substrate and the alkylating agent are supplied to a first of the reaction stages in relative amounts to provide a first mole ratio of aromatic substrate to alkylating agent. The effluent from the first reaction zone is supplied to a second reaction stage. Alkylating agent is separately supplied to the second reaction stage in an amount to provide a mole ratio of the aromatic substrate to the alkylating agent which is less than corresponding ratio of these reactants as supplied to the first recited alkylation stage.