Improved alkylation catalysts, alkylation methods, and methods of making alkylation catalysts are described. The alkylation method comprises reaction over a solid acid, zeolite-based catalyst and can be conducted for relatively long periods at steady state conditions. The alkylation catalyst comprises a crystalline zeolite structure, a Si/Al molar ratio of 20 or less, less than 0.5 weight percent alkali metals, and further having a characteristic catalyst life property. Some catalysts may contain rare earth elements in the range of 10 to 35 wt %. One method of making a catalyst includes a calcination step following exchange of the rare earth element(s) conducted at a temperature of at least 575 C. to stabilize the resulting structure followed by an deammoniation treatment. An improved method of deammoniation uses low temperature oxidation.

A process for the upgrading of hydrocarbon streams, i.e., processing any hydrocarbon feed streams rich in benzene and sulphur compounds. The process for simultaneous hydrodesulfurization and benzene conversion to higher alkylated aromatic molecules (C.sub.7 to C.sub.10 aromatics), without need of prior treatment like distillation, or sulfur removal. The hydrocarbon feed streams are processed over sulfided metal catalyst impregnated on acid support simultaneously desulfurizes and alkylates the benzene molecules.

A continuous process for producing adamantane includes the steps of: 1) providing a liquid feed stream comprising endo-tetrahydrodicyclopentadiene; and 2) passing the liquid feed stream through a first reaction zone filled with a hydrogenation protective agent and a second reaction zone filled with an isomerization catalyst sequentially to carry out hydroisomerization reaction and obtain adamantane.