Disclosed are a catalyst system capable of selectively oligomerizing olefins including ethylene and a method for preparing an olefin oligomer by using the same and, specifically, a novel catalyst system capable of trimerizing and tetramerizing olefins, unlike olefin oligomerization catalyst systems that have been reported so far, and a method for preparing an olefin oligomer by using the same. The present invention provides a catalyst system for olefin oligomerization, the catalyst system comprising: a ligand compound represented by chemical formula 1; a chromium compound; a metal alkyl compound; and an aliphatic or alicyclic hydrocarbon solvent.

A process is provided for the selective oligomerisation of C5 to C20 alpha-olefins to produce polyalphaolefin oligomers with a molecular weight distribution that is suitable for use in lubricant base oils.

An oxo-nitrogenated iron complex having general formula (I) or (II) wherein: R.sub.1 and R.sub.2 identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.3, identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; X.sub.1 and X.sub.2, identical or different, represent a halogen atom such as, for example, chlorine, bromine, iodine; or are selected from linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, OCOR.sub.4 groups or OR.sub.4 groups wherein R.sub.4 is selected from linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups. Said oxo-nitrogenated iron complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes. ##STR00001##

Polymerisation catalysts and systems comprising said catalysts for polymerising carbon dioxide and an epoxide, a lactide and/or lactone, and/or an epoxide and an anhydride. The catalyst is of formula (I):

##STR00001##

Wherein M.sub.1 and M.sub.2 are independently selected from Zn(II), Cr(II), Co(II), Cu(II), Mn(II), Ni(II), Mg(II), Fe(II), Ti(II), V(II), Cr(III)-X, Co(III)-X, Ni(III)-X, Mn(III)-X, Fe(III)-X, Ca(II), Ge(II), AI(III)-X, Ti(III)-X, V(III)-X, Ge(IV)-(X).sub.2 or Ti(IV)-(X).sub.2. R.sub.3A is different from R.sub.3B; and/or at least one occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6 is different to a remaining occurrence of E.sub.3, E.sub.4, E.sub.5 and E.sub.6. A ligand, a process of asymmetric N-substitution of a symmetrical ligand and a process for the reaction of: (i) carbon dioxide with an epoxide; (ii) an epoxide and an anhydride; and/or (iii) a lactide and/or a lactone, in the presence of a catalyst is also described.

A method can prepare a carboxylic ester. The method includes reacting an aldehyde in the presence of an aluminium alkoxide applied to a support material.

Processes for regenerating ionic liquid catalyst in which reaction vessel is operated under conditions sufficient to perform, in the presence of an ionic liquid catalyst, a hydrocarbon conversion reaction and provide a reaction effluent. The reaction effluent is separated into a hydrocarbon phase and a spent ionic liquid catalyst, wherein the spent ionic liquid catalyst includes conjunct polymer. The spent ionic liquid catalyst is contacted with hydrogen in a regeneration zone at conditions sufficient to reduce an amount of conjunct polymer in the spent ionic liquid catalyst to provide a regenerated effluent. The regenerated effluent is separated into a liquid phase comprising regenerated ionic liquid catalyst and a vapor phase comprising hydrogen and hydrogen chloride. The hydrocarbon phase is separated into a plurality of liquid hydrocarbon streams. The vapor phase is isolated from the liquid hydrocarbon streams. Alkylation processes are also disclosed.

Methods of selectively synthesizing n-tetrasilane are disclosed. N-tetrasilane is prepared by catalysis of silane (SiH.sub.4), disilane (Si.sub.2H.sub.6), trisilane (Si.sub.3H.sub.8), or mixtures thereof. More particularly, the disclosed synthesis methods tune and optimize the n-tetrasilane:i-tetrasilane isomer ratio. The isomer ratio may be optimized by selection of process parameters, such as temperature and the relative amount of starting compounds, as well as selection of proper catalyst. The disclosed synthesis methods allow facile preparation of n-tetrasilane.

A process to form a cyclic olefin polymerization catalyst which includes contacting a metal alkoxide with a transition metal halide to form a transition metal precatalyst, and contacting the transition metal precatalyst with a metal alkyl activator to form the activated catalyst comprising a transition metal carbene moiety. A cyclic olefin polymerization process is also disclosed.

A process for synthesizing at least one levulinate ester, said process comprising the reaction of furfuryl alcohol with at least one other alcohol in the presence of water and at least one catalyst, said furfuryl alcohol being present in a quantity of at least 5% by weight, based on the total weight of the alcohols, and said catalyst comprising at least one triflate ligand and at least one metal selected from bismuth, gallium, aluminum, tin and iron.

The present invention is directed to processes from producing beta-lactone and beta-lactone derivatives using heterogenous catalysts. In preferred embodiments of the present invention, the processes comprise the steps: passing a feed stream comprising an epoxide reagent and a carbon monoxide reagent to a reaction zone; contacting the epoxide reagent and the carbon monoxide reagent with a heterogenous catalyst to produce a beta-lactone product in the reaction zone; and removing the beta-lactone product from the reaction zone. In preferred embodiments, the heterogenous catalyst comprises a solid support containing a cationic Lewis acid functional group and a metal carbonyl compound comprising at least one of anionic metal carbonyl compound or a neutral metal carbonyl compound. In certain preferred embodiments, the epoxide reagent and carbon monoxide reagent have a biobased content.