553 results about "Chromium Compounds" patented technology

The invention relates to a method for producing an ethylene polymer, comprising performing polymerization of ethylene in co-presence of hydrogen using a trialkylaluminum compound-carried chromium catalyst, wherein the chromium catalyst is obtained by calcination-activating a chromium compound that is carried on an inorganic oxide carrier in a non-reducing atmosphere to convert chromium atoms in the chromium compound into hexavalent chromium atoms for at least a portion thereof, and treating with a trialkylaluminum compound in an inert hydrocarbon solvent to carry thereon and removing to dry the solvent so that the chromium atoms are not over-reduced by the trialkylaluminum compound, and to an ethylene polymer suitable for blow molded articles obtained by the production method. The ethylene polymer of the invention have improved environment stress crack resistance (ESCR) and impact resistance in a good balance and are suitable for molded blow articles, in particular large size blow molded articles.

A method of preparing a catalyst comprising contacting a support with a trivalent titanium compound and a chromium-containing compound. A catalyst composition comprising a support, chromium, and titanium, wherein the titanium is derived from TiCl3, Ti2(SO4)3, Ti(OAc)3, Ti(+3) oxylate, Ti(NO3)3, Ti(+3) lactate or combinations thereof.

The present invention provides a method of producing oligomers of olefins, comprising reacting olefins with a catalyst under oligomerization conditions. The catalyst can be the product of the combination of a chromium compound and a heteroaryl-amine compound. In particular embodiments, the catalyst compound can be used to trimerize or tetramerize ethylene to 1-hexene, 1-octene, or mixtures of 1-hexene and 1-octene.

The present invention relates to a catalyst composition for ethylene oligomerization and the use thereof. Such catalyst composition includes chromium compound, ligand containing P and N, activator and accelerator; wherein the chromium compound is selected from the group consisting of acetyl acetone chromium, THF-chromium chloride and Cr(2-ethylhecanoate)3; general formula of the ligand containing P and N is shown as:in which R1, R2, R3 and R4 are phenyl, benzyl, or naphthyl. R5 is isopropyl, butyl, cyclopropyl, cyclopentyl, cyclohexyl or fluorenyl; the activatior is methyl aluminoxane, ethyl aluminoxane, propyl aluminoxane and / or butyl aluminoxane; the accelerator is selected from the group consisting of 1,1,2,2,-tetrachloroethane, 1,1,2,2-tetrabromoethane, 1,1,2,2-tetrafluoroethane, and compounds having a formula of X1R6X2, in which X1 and X2 are F, Cl, Br, I or alkoxyl, R6 is alkylene or arylene group; the molar ratio of chromium compound, ligand containing P and N, activator and accelerator is 1:0.5˜10:50˜3000:0.5˜10. After mixing the four components mentioned previously under nitrogen atmosphere for 10 minutes, they are incorporated to the reactor, or these four components are incorporated directly into the reactor. Then ethylene is introduced for oligomerization. Such catalyst can be used in producing 1-octene through ethylene oligomerization. It is advantageous in high catalysing activity, high 1-octene selectivity, etc. The catalytic activity is more than 1.0×106 g product·ma−1 Cr·h−1, the fraction of C8 linear α-olefin is more than 70% by mass.

Methods of preparing a polymerization catalyst are provided that include contacting a support comprising alumina with a sulfating agent and with chromium. In an embodiment in which the chromium is provided from a chromium compound such as chromium oxide, the support may be calcined after loading the sulfating agent and the chromium on the support. Alternatively, the sulfating agent can be loaded on the support while calcining it. In another embodiment in which the chromium is provided from an organochromium compound, the support may be calcined after contacting it with the sulfating agent and before contacting it with the organochromium compound. Catalysts compositions formed by the foregoing method are provided. In an embodiment, catalyst compositions comprise chromium and a sulfate treated alumina support. The catalyst compositions have an activity for ethylene polymerization that is at least about 25% greater than an activity of the same catalyst without sulfate.

An acidic aqueous solution containing a water soluble trivalent chromium compound is provided with a additive for improving corrosion resistance and reducing precipitation of trivalent chromium over time. A suitable additive is nitrilotris (methylene) triphosphonic acid (NTMP).