摘要:
Disclosed are a tandem catalyst for synthesizing methyl acetate from carbon dioxide, a method for preparing the same, and a method for preparing methyl acetate using the same. The tandem catalyst of the present invention includes a first catalyst having a core-shell structure including a composite metal oxide core and a silica shell surrounding a surface of the composite metal oxide core, and a second catalyst including nano-ferrierite (N-FER) zeolite.
摘要:
SCR-active molecular-sieve based catalysts with improved low-temperature performance are made by heating a molecular-sieve in a non-oxidizing atmosphere with steam (hydrothermal treatment), or in a reducing atmosphere without steam (thermal treatment), at a temperature in the range of 600-900° C. for a time period from 5 minutes to two hours. The resulting SCR-active iron-containing molecular sieves exhibit a selective catalytic reduction of nitrogen oxides with NH3 or urea at 250° C. that is at least 50% greater than if the iron-containing molecular-sieve were calcined at 500° C. for two hours without performing the hydrothermal or thermal treatment.
摘要:
The invention relates to the production of aromatic hydrocarbon by the conversion of a feed comprising C2+ non-aromatic hydrocarbon, e.g., natural gas. The invention is particularly useful in converting natural gas to liquid-phase aromatic hydrocarbon, which can be more easily transported away from remote natural gas production facilities. The conversion is carried out in the presence of a dehydrocyclization catalyst comprising dehydrogenation and molecular sieve components. The dehydrocyclization catalyst has an average residence time of 90 seconds or less.
摘要:
Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a mordenite zeolite synthesized from TEA or MTEA, optionally at least one first metal of Group 10 of the IUPAC Periodic Table, and optionally at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.
摘要:
A method is disclosed for the preparation of a metal exchanged microporous materials, e.g. metal exchanged silicoaluminophosphates or metal exchanged zeolites, or mixtures of metal exchanged microporous materials, comprising the steps of providing a dry mixture of a) one or more microporous materials that exhibit ion exchange capacity and b) one or more metal compounds; heating the mixture in a gaseous atmosphere containing ammonia and one or more oxides of nitrogen to a temperature and for a time sufficient to initiate and perform a solid state ion exchange of ions of the metal compound and ions of the microporous material; and obtaining the metal-exchanged microporous material.
摘要:
The invention relates to a process and apparatus for preparing nitric acid by catalytic oxidation of NH3 by means of oxygen and subsequent reaction of the NOx formed with an absorption medium in an absorption tower, which comprises a catalyst bed for N2O decomposition arranged in the process gas downstream of the catalytic NH3 oxidation and upstream of the absorption tower in the flow direction and a catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas downstream of the absorption tower in the flow direction, wherein the amount of N2O removed in the catalyst bed for N2O removal arranged in the process gas is not more than that which results in an N2O content of >100 ppmv and a molar N2O/NOx ratio of >0.25 before entry of the tailgas into the catalyst bed for NOx reduction and the catalyst bed for NOx reduction and effecting a further decrease in the amount of N2O arranged in the tailgas contains at least one iron-loaded zeolite catalyst and NH3 is added to the tailgas before entry into the catalyst bed in such an amount that an NOx concentration of
摘要:
An exhaust system for an internal combustion engine, the exhaust system comprising, a lean NOx trap, and a wall flow monolithic substrate having a pre-coated porosity of 40% or greater, and comprising an oxidation catalytic zone, the oxidation catalytic zone comprising a platinum group metal loaded on a first support, the first support comprising at least one inorganic oxide and a zinc compound.
摘要:
Disclosed are a catalyst system and its use in a process for the conversion of a feedstock containing C8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst system comprises (a) a first catalyst bed comprising a first catalyst composition, said first catalyst composition comprising a zeolite having a constraint index of 3 to 12 combined (i) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (ii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table; and (b) a second catalyst bed comprising a second catalyst composition, said second catalyst composition comprising (i) a meso-mordenite zeolite, combined (ii) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (iii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said meso-mordenite zeolite is synthesized from TEA or MTEA and having a mesopore surface area of greater than 30 m2/g and said meso-mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.
摘要:
This invention relates to a process for producing ethanol comprises supplying a feed comprising carbon monoxide, hydrogen and dimethyl ether to a reaction zone operated under conditions such that (i) part of the carbon monoxide in the feed reacts with part of the hydrogen in the feed to produce methanol; (ii) part of the carbon monoxide in the feed reacts with at least part of the dimethyl ether in the feed to produce methyl acetate; and (iii) part of the hydrogen in the feed reacts with at least part of the methyl acetate produced in (ii) to produce an effluent comprising methanol and ethanol. At least part of the ethanol is recovered from the effluent and at least part of the methanol is dehydrated to produce dimethyl ether, which is recycled to the reaction zone.
摘要:
Catalysts and articles useful for selective catalytic reduction (SCR) and other exhaust gas treatments are disclosed. The catalysts comprise an octahedral molecular sieve (OMS) comprising manganese oxide and an aluminosilicate and/or silicoaluminophosphate large-pore or medium-pore molecular sieve.