The present invention discloses a composite catalyst for the photocatalytic isomerization of norbornadiene to prepare quadricyclane, comprising: a solid photocatalyst, selected from the group consisting of TiO.sub.2, Ti-MCM-41, Ti-SBA-15, ZnO, WO.sub.3, Ta.sub.2O.sub.5 or SrTiO.sub.3; and an organic photo-sensitizer loaded on the surface or in the channel of said solid photocatalyst, selected from benzophenone, acetophenone, Michler's Ketone, tetraethyl Michler's Ketone, and diethyl Michler's Ketone, where the organic photo-sensitizer is present in the solid photocatalyst in an amount of 0.5% to 20% by weight. The catalyst of the invention can catalyze a target reaction under the condition that no solvent is used, and the yield of the target product quadricyclane is higher. Furthermore, the catalyst of the invention has a stable activity, and it can be recycled. The invention further discloses a process for preparing the composite catalyst.

The present invention relates to a process for the oligomerization of ethylene, comprising: a) oligomerization of ethylene in a reactor in the presence of solvent and catalyst; b) transferring reactor overhead effluent to an externally located cooling device and recycling condensed effluent into the reactor; c) transferring the reactor bottom effluent to a series of fractionation columns and, in the following order, i) optionally separating a C4 fraction, ii) separating a C6 fraction, iii) simultaneously separating C8 and C10 fractions and recycling thereof into the reactor , and iv) separating residues comprising C12 fractions, spent catalyst polymer material and quench media, from the process, wherein the solvent is separated in any of the steps i)-iv)and/or in an additional step.

Methods of preparing oligomers of an olefin are provided. The methods can include providing a composition that includes an alkylaluminum compound, a chromium compound, and a hydrocarbon solvent. The hydrocarbon solvent can include n-undecane, a C8-C11 alkane compound having one branch, or a mixture thereof. The methods can further include contacting an olefin with the composition to form oligomers of the olefin. The olefin can include ethylene, and the oligomers of the olefin can include 1-hexene.

Method of forming an olefin from a first olefin and a second olefin in a metathesis reaction, comprising step (i): (i) reacting the first olefin with the second olefin in the presence of a silica supported Mo- or W-alkylidene catalyst, wherein the first olefin and the second olefin are different from one another.

The present invention relates to a catalyst system for olefin oligomerization and a method for olefin oligomerization, and more specifically, a catalyst system for olefin oligomerization and a method for olefin oligomerization that have more improved supporting efficiency due to a ligand compound capable of functioning as a tether to a support, and thus, exhibit high activity in the olefin oligomerization even with smaller amounts of catalyst composition and cocatalyst, thus enabling more efficient preparation of alpha-olefins.

N.sup.2-phosphinyl formamidine compounds and N.sup.2-phosphinyl formamidine metal salt complexes are described. Methods for making N.sup.2-phosphinyl formamidine compounds and N.sup.2-phosphinyl formamidine metal salt complexes are also disclosed. Catalyst systems utilizing the N.sup.2-phosphinyl formamidine metal salt complexes are also disclosed along with the use of the N.sup.2-phosphinyl amidine compounds and N.sup.2-phosphinyl amidinate metal salt complexes for the oligomerization and/or polymerization of olefins.

The invention discloses a continuous process for producing high-pure quadricyclane, in which a reaction-rectification integral process or a reaction followed by rectification process may be employed. The two processes both use a novel composite catalyst which is obtained by loading an organic photo-sensitizer on a solid photocatalyst, and the composite catalyst has a high activity and a good stability. In the reaction-rectification integral process, the composite catalyst is used by being blended with rectification fillers or covering the rectification fillers, so as to achieve the integration of the reaction and the rectification. In the reaction followed by rectification process, the composite catalyst and the rectification fillers are placed separately from each other. The two processes achieve a relatively short residence time of reactants, produce highly-pure quadricyclane, and reduce the formation of cokes.

Provided are a catalyst system for olefin oligomerization reaction and a method for olefin oligomerization, and more particularly, a catalyst system for olefin oligomerization reaction and a method for olefin oligomerization, which enable more efficient preparation of alpha-olefin, because a catalytic active ingredient is supported on a support, thereby exhibiting high activity in olefin oligomerization reaction even by using smaller amounts of a catalyst composition and a cocatalyst.

Provided are a catalyst composition and a method of oligomerizing olefins using the same. When the catalyst composition according to the present invention is used, oligomerization and copolymerization of olefin monomers may be performed in a single reactor at the same time with high efficiency without a separate process of preparing alpha-olefin. Therefore, costs for preparing or purchasing comonomers which are expensive raw materials may be reduced, thereby reducing the production cost of a final product. Contents of SCB (short chain branch) and LCB (long chain branch) in the polyolefin may be increased without separate feeding of comonomers, thereby producing high-quality linear low-density polyethylene.

The present invention concerns a process for converting biomass into useful organic building blocks for the chemical industry. The process involves the use of molybdenum catalysts of the formula A.sup.a+a(Mo.sub.vX.sub.xR.sup.1.sub.yR.sup.2.sub.zR.sup.3e).sup.a*3, which may be readily prepared from industrial molybdenum compounds.