6 results about "CHROMIUM COMPLEX" patented technology

The application provides a method for efficiently and selectively removing iron and chromium from cobalt-nickel hydroxide raw materials, which can realize the synchronous and deep removal of iron and chromium impurities for high-iron and high-cobalt nickel hydroxide raw materials through the synergistic process of acid leaching, reduction pH adjustment, oxidation precipitation and solid-liquid separation, and the concentrations of iron and chromium in the purified nickel-cobalt liquid are both controlled below 10 mg / L, and the impurity removal precision meets the subsequent high-purity production requirements; the chromium-goethite co-precipitation crystal product is generated in situ in the reaction, and has excellent settling and filtering performance, solving the problems of difficult colloid precipitation and filtration and easy equipment blockage in the traditional method, and the process route is short and the reaction conditions are mild, which can effectively reduce the adsorption entrainment and co-precipitation loss of nickel and cobalt valuable metals, and while realizing the efficient and deep purification of iron and chromium, the excellent solid-liquid separation performance and high main metal recovery rate are also considered, and the method is suitable for the industrial purification treatment of high-iron and high-chromium complex cobalt-nickel raw materials.

The invention discloses a method for preparing syndiotactic polystyrene through transition metal catalysis. According to the method, an aryl ether-transition metal chromium compound is adopted to catalyze styrene to polymerize so as to prepare syndiotactic polystyrene. According to the preparation method of the compound, an aryl ether compound reacts with tetrahydrofuran chromium trichloride to obtain a chromium complex, then the chromium complex and aluminum alkyl form a catalytic system, bulk polymerization is performed in styrene to obtain syndiotactic polystyrene, and the syndiotactic polystyrene has the advantages of good stereoselectivity and high activity.

This invention relates to the field of organic synthesis technology, specifically to a method for synthesizing chiral β-amino alcohols. This method uses a chiral chromium complex as a catalyst to catalyze the reaction of aldehydes with imines to prepare chiral β-amino alcohols. The synthetic method provided by this invention uses simple and readily available reactants, is easy to operate, operates under mild conditions, and has good universality for the reaction substrates. It is applicable not only to alkyl aldehydes but also to aromatic aldehydes, exhibiting broad adaptability and practicality. Furthermore, the reaction products demonstrate excellent stereoselectivity, making it highly suitable for industrial production and application.

The invention provides an ethylene oligomerization method which comprises the following steps: premixing feed gas containing ethylene and hydrogen with an organic solvent to obtain a premix; the premix is in contact with a catalyst system a for a pre-reaction, and a pre-reactant is obtained; the catalyst system a is a bridged diphosphine chromium complex; the pre-reactant is in contact with a catalyst system b for a polymerization reaction, and a product containing alpha-olefin is obtained; the catalyst system b is an organic aluminum compound. According to the method disclosed by the invention, the activity and the product selectivity of the catalyst are improved by premixing the gas phase and the liquid phase and pre-activating the catalyst system, so that the utilization efficiency of the catalyst is improved, and the production cost is reduced.

This invention discloses a method for treating chromium-containing wastewater and its application in the preparation of electromagnetic shielding leather. The method utilizes a Fenton-like reaction with nano-zero-valent iron as a catalyst to destroy the difficult-to-remove chromium complex structure in the chromium-containing wastewater. Simultaneously, magnesium ions are added to prepare a magnesium-chromium-iron ternary hydrotalcite nanomaterial with tanning properties. This material is used as a tanning agent in the leather tanning process, imparting electromagnetic shielding properties to the finished leather. Furthermore, the electromagnetic shielding leather prepared by this invention meets the performance requirements of leather, exhibiting good physical and mechanical properties, good resistance to hot air aging and ultraviolet light aging, and high folding resistance. As a wearable electromagnetic shielding leather, it provides 18 dB electromagnetic shielding performance in the 8–12 GHz electromagnetic wave range while retaining the softness of leather. This invention provides a pathway for the treatment of chromium-containing wastewater and the preparation of electromagnetic shielding leather.

The invention discloses a binuclear chromium complex, an ethylene oligomerization catalyst system and application of the binuclear chromium complex and the ethylene oligomerization catalyst system. The binuclear chromium complex has a structure as shown in a formula I. A catalyst system containing the complex is high in catalytic activity, 1-hexene and 1-octene can be prepared with high selectivity, and the generation amount of polyethylene hindering process stability can be remarkably reduced while the activity of the catalyst is not reduced. Formula I.