摘要:
A method of reclaiming a titanosilicate from a deactivated or spent oxidation catalyst containing a titanosilicate having deposited thereon one or more catalytic metals, such as gold, and optionally, one or more promoter metals, the method involving treating the deactivated catalyst with an oxidant; contacting the oxidant-treated catalyst with acid, preferably aqua regia; washing the titanosilicate to remove residual acid; and optionally drying and/or calcining. A method of reconstituting an active oxidation catalyst from a spent or deactivated oxidation catalyst, the method involving reclaiming the titanosilicate as noted above, and then depositing one or more catalytic metals and, optionally, one or more promoter metals onto the reclaimed titanosilicate.
摘要:
A process and catalyst for the hydro-oxidation of an olefin having three or more carbon atoms, such as propylene, to form an olefin oxide, such as propylene oxide. The process involves contacting the olefin with oxygen in the presence of hydrogen and a hydro-oxidation catalyst under reaction conditions; the catalyst comprising gold nanoparticles deposited on a nanoporous titanium-containing support, prepared by depositing a gold-ligand cluster complex onto the support to form a catalyst precursor, and then heating and/or chemically treating the catalyst precursor to form the hydro-oxidation catalyst composition. The hydro-oxidation catalyst exhibits stabilized catalyst activity, enhanced lifetime, and improved hydrogen efficiency.
摘要:
A process and catalyst for the hydro-oxidation of an olefin having three or more carbon atoms, such as propylene, to form an olefin oxide, such as propylene oxide. The process involves contacting the olefin with oxygen in the presence of hydrogen and a hydro-oxidation catalyst under reaction conditions; the catalyst comprising gold nanoparticles deposited on a nanoporous titanium-containing support, prepared by depositing a gold-ligand cluster complex onto the support to form a catalyst precursor, and then heating and/or chemically treating the catalyst precursor to form the hydro-oxidation catalyst composition. The hydro-oxidation catalyst exhibits stabilized catalyst activity, enhanced lifetime, and improved hydrogen efficiency.
摘要:
A process of preparing alkylene oxides comprises steps of: (1) optionally forming a hypochlorite solution; (2) contacting chlorine with a solution of a hypochlorite below about 60.degree. C., and a pH of less than about 5.5, with sufficient micromixing to achieve a product hypochlorous acid in a yield of at least about 80 percent; (3) separating at least a portion the hypochlorous acid from an aqueous metal chloride solution wherein the solution is sprayed as droplets; (4) distilling the remaining liquid phase; (5) absorbing the hypochlorous acid and dichlorine monoxide in low-chlorides water to produce a low-chlorides aqueous hypochlorous acid solution; (6) contacting the low-chlorides aqueous hypochlorous acid solution with an olefin in a continuous process to form a olefin chlorohydrin; (7) optionally contacting the olefin chlorohydrin with a base to form a alkylene oxide and a salt solution; and (8) optionally separating the alkylene oxide from the salt solution. (9) optionally removing chlorates from the chloride brine by contacting the chlorates with acid to convert the chlorates to chlorine; and (10) optionally recycling the chlorine. The process yields particularly high yields of the alkylene oxide without substantial production of by-products.
摘要:
Described herein is a method for producing epoxides which is continuous, inhibits formation of chlorinated byproducts, and eliminates or substantially reduces waste water discharge. The method includes:(a) forming a low chlorides aqueous hypochlorous acid solution;(b) contacting the low chlorides aqueous hypochlorous acid solution with at least one unsaturated organic compound to form an aqueous organic product comprising at least olefin chlorohydrin;(c) contacting at least the olefin chlorohydrin with an aqueous alkali metal hydroxide to form an aqueous salt solution product containing at least epoxide; and(d) isolating the epoxide from the aqueous salt solution;wherein water is recovered from the product of at least Step (b) and recycled into Step (a) for use in forming the low chlorides aqueous hypochlorous acid solution. In this process, not only is the water internally recycled after Step (b), but a concentrated brine solution is generated in both Steps (a) and (d) which is useful in other processes such as electrochemical production of chlorine and caustic. The chlorine and caustic, in turn, may then be recycled back to the method of this invention.
摘要:
Shear mixing apparatuses and associated methods are disclosed for producing small gas bubbles of a diameter of less than about 0.1 millimeters in a liquid, whereby mass transfer of the gas into the liquid is improved (as compared to the mass transfer achieved by conventional large bubble generators under the same circumstances) in applications benefiting by such improved mass transfer, involving injecting a gas under pressure via one or more orifices into a liquid that is flowing at a velocity sufficient to cause bubbles formed at the orifice(s) to subdivide to the desired small bubble size.
摘要:
This invention is a method for forming hypohalous acid in a mass transfer device. The method comprises: (1) feeding into the device a stream of caustic solution comprising at least one alkali or alkaline earth metal of a hydroxide, oxide, hypohalite, bicarbonate, or carbonate; (2) feeding a stream comprising halogen gas into the device; (3) reacting at least some of the halogen gas with the caustic solution to form a solution containing hypohalous acid; (4) desorbing the hypohalous acid from the solution and into the stream of halogen gas; and (5) removing the stream of halogen gas from the device. In this method, the mass transfer device comprises a porous rotor which is permeable to the streams, and is rotated about an axis such that the streams flow through the rotor and the stream of caustic solution flows radially outward from the axis.