A ligand based chromium catalyst and application in catalyzing ethylene oligomerization are disclosed. The chromium catalyst is formed by a chromium compound and an organic ligand containing P and/or N. The substituents on N and P of the ligand can be replaced, whereby selective ethylene trimerization and tetramerization can be realized so as to produce 1-hexene and 1-octene at the same time.

A composition is capable of curing via condensation reaction. The composition uses a new condensation reaction catalyst. The new condensation reaction catalyst is used to replace conventional tin catalysts. The composition can react to form a gum, gel, rubber, or resin.

The invention relates to novel metal complexes useful as catalysts in redox reactions (such as, hydrogen (H.sub.2) production). In particular, the invention provides novel transition metal (e.g., cobalt (Co) or nickel (Ni)) complexes, in which the transition metal is coupled with N,N-Bis(2-pyridinylmethyl)-2,2-Bipyridine-6-methanamine (DPA-Bpy), 6-((bis(pyridin-2-ylmethyl)amino)methyl)-N,N-dimethyl-2,2-bipyridin-6-amine (DPA-ABpy), N,N-bis((isoquinolin-1-yl)methyl)(6-(pyridin-2-yl)pyridin-2-yl)methanamine (DIQ-Bpy), or a derivative thereof. The invention also relates to a method of producing H.sub.2 from an aqueous solution by using the metal complex as a catalyst. In certain embodiments, the invention provides a metal complex of the formulae as described herein.

Disclosed is a process for the purification of a mixed diol stream. The mixed diol stream comprising two-, three-, and four-carbon diols is separated into component diols by extraction with a hydrophobic solvent mixture. The diols recovered in the extractant may be removed from the extractant stream by back extraction with water or by distillation with an azeotrope-forming agent present, preferably an azeotroping agent already present in the extractant mixture.

A catalyst composition and a process for di-, tri- and/or tetramerization of ethylene, wherein the catalyst composition comprises a chromium compound, a ligand of the general structure R.sub.1R.sub.2PN(R.sub.3)P(R.sub.4)N(R.sub.5)PR.sub.6R.sub.7, or any cyclic derivatives thereof, wherein at least one of the P or N atoms of the PNPNP-unit is member of a ring system, the ring system being formed from one or more constituent compounds of the ligand by substitution, and a co-catalyst or activator.

The present invention provides a borylimide catalyst and further relates to compositions comprising the borylimide catalysts and processes for the polymerisation of olefins (e.g. ethylene) using the borylimide catalysts or the compositions comprising the borylimide catalysts.