Generally, regenerable, encapsulated metal oxide catalysts comprising a ceramic matrix and metal catalysts may be used to convert alkanes to alkenes. The encapsulated metal oxide catalyst may be tailored to produce a variety of alkenes including ethylene, butylene, and propylene. Further, the encapsulated metal oxide catalysts advantageously allow for regeneration and reactant recovery for cost effective and environmentally friendly processes.

Disclosed is a process for preparation of n-propyl benzene. The process gives high selectivity and yield of n-propyl benzene by single step catalytic alkylation that involves contacting a mixture of aromatic hydrocarbon having an active hydrogen on a saturated -carbon, such as toluene, and an alkene, such as ethylene, in presence of a metal catalyst, a solid support, and an initiator. Following the alkylation, aqueous and organic phases are separated from a reaction mixture. The aqueous phase is separated for recovery of the catalyst, the solid support, and un-reacted aromatic hydrocarbon (e.g., toluene); and the organic phase is separated for obtaining n-propyl benzene and byproduct. Thus, the catalyst phase can be recovered and recycled in the next alkylation reaction. Also, the process facilitates recovery and recycling of the byproduct for the better selectivity.

A method for producing an olefin dimer, including a step of subjecting an olefin containing an olefin having from 4 to 10 carbon atoms to a dimerization reaction in the presence of an olefin dimerization catalyst containing a compound (B) represented by B.sub.nX (wherein B is Na or K, X is CO.sub.3, SO.sub.4, SiO.sub.3, F, Cl, or Br, and n is an integer of 1 or 2 determined by a valence of X), and an alkali metal (D), a content ratio of which is in a specific range, and an olefin dimerization catalyst in which a pore diameter and a volume of pores of the compound (B) are within specific ranges.

A lanthanum dioxide carbonate catalyst, a preparation method and a use thereof are provided. The lanthanum dioxide carbonate catalyst comprises hexagonal crystalline lanthanum dioxide carbonate and hexagonal crystalline lanthanum dioxide carbonate containing a doping element R. The method includes the steps of (1) adding an alkali solution to a solution of lanthanum source, and then performing a solid-liquid separation and a drying to obtain lanthanum hydroxide; (2) contacting a solution of a compound containing the doping element R with lanthanum hydroxide, and then performing a drying; (3) calcining the dried product of step (2) under a carbon-containing atmosphere to obtain a lanthanum dioxide carbonate catalyst.