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AssigneeDow Global Technologies LLC
InventorsSteven L. F. Corthals, Thomas Davidian, Gerolamo Budroni, Peter E. Groenendijk
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The present invention provides methods for making propanal in a reaction comprising the oxidative coupling of methane (OCM) and oxygen as a reactant stream in a gas phase reaction, preferably in the presence of water or steam, to form ethylene, ethane, carbon dioxide (CO2), water and syngas (CO and H2) in a first reactor as an ethylene stream, and then forming propanal in a second reactor by feeding to the second reactor the ethylene stream with the syngas from the first reactor in the gas phase and hydroformylating in the presence of a catalyst for a water shift reaction. In the method, the ratio of H2 to CO in the syngas is maintained by either co-feeding steam into the first reactor or the second reactor to generate additional H2 in the syngas, or by forming CO in the second reactor from the water shift reaction by feeding the CO2 from the ethylene stream into the second reactor.
A method for making propanal in a reaction comprising the oxidative coupling of methane (OCM reaction) and oxygen as a reactant stream in a gas phase reaction to form ethylene, ethane, carbon dioxide (CO2), water and syngas (CO and H2) as an ethylene stream in a first reactor containing an OCM zone and a downstream thermal cracking zone to form ethylene from ethane, and then forming propanal in a second reactor by feeding to the second reactor the ethylene stream from the first reactor in the gas phase and hydroformylating the ethylene stream to form a propanal containing product stream in the presence of a catalyst for a water gas shift reaction in which water and carbon monoxide (CO) form carbon dioxide and hydrogen gas (H2) and for the hydroformylating, wherein the molar ratio of the syngas to the total amount of ethylene and ethane in the ethylene stream before the downstream thermal cracking zone ranges from 2:1 to 10:1, and, further wherein, the molar ratio of total CO2 and CO to total ethylene and ethane in the ethylene stream before the downstream thermal cracking zone ranges from 0.97:1 to 5:1.
Dependencies are inferred from the claim text.
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By oxo-reactions: asymmetric hydroformylation
By reaction of water vapour with carbon monoxide: using catalysts
By reaction of hydrocarbons with gasifying agents: using oxygen; using mixtures containing oxygen as gasifying agents
By condensation of hydrocarbons with partial elimination of hydrogen: oxidative coupling
About 10 years 8 months of term left · ends 13 Jun 2037 (estimated)
The present invention relates to methods for making propanal, such as for use in making methyl methacrylate (MMA), in a reaction comprising oxidative coupling of methane and oxygen (OCM reaction) in a first reactor in a gas phase reaction, preferably, in the presence of water or steam, to form a stream of ethylene, ethane, water, syngas (CO and H2) and carbon dioxide, and forming propanal by hydroformylation of the ethylene with the syngas in a second reactor wherein after the OCM reaction, the molar ratio of the syngas to the total amount of ethylene and ethane after the OCM reaction ranges from 2:1 to 10:1, or, preferably, from 2.5:1 to 5:1, or, more preferably, from 3.2:1 to 4.5:1, and, further wherein the molar ratio of total CO2 and CO to (ethylene+ethane) ranges from 0.97:1 to 5:1, or, preferably, from 1:1 to 4:1, or, more preferably, from 1.1:1 to 2.5:1.
The development of extraction methods for shale gas has had a large impact on the feedstock availability of natural gas. Current shale gas and more generally natural gas, developments are making it a cheap and abundant source of hydrocarbons. These feedstocks are gas mixtures containing typically 80-99% methane, 1-20% ethane, 1-5% higher hydrocarbons and other non hydrocarbon constituent such as CO2 and nitrogen. However, the larger fraction “methane” today is mainly used as fuel or as feedstock for syngas, a mixture of CO and H2. Thus, converting methane or shale gas directly into useful products remains today a technical challenge.
Today, one of the most explored routes for the conversion of methane into products is oxidative coupling of methane or OCM. OCM can be used to make ethylene which can be used itself or hydroformylated into propanal (propionaldehyde) with the addition of syngas catalyzed by a NiS catalyst. See S. S. C. Chuang, Applied Catalysis, 66 (1990) L1, also see the “example section”. Propanal can be converted to methacrolein via condensation with formaldehyde. Oxidative esterification of methacrolein results in the formation of methyl methacrylate (MMA). The oxidative coupling of methane to ethylene reaction can be expressed, as follows (the arrow meaning it is an equilibrium reaction in which favorable equilibrium goes to the right side of the equation): 2CH4+O2→C2H4+2H2O.
FIG. 1 is a schematic of the methods of the present invention; and
FIG. 2 is a schematic of a known process in accordance with the art.
All temperatures are in ° C., unless otherwise indicated.
Unless otherwise indicated, all temperatures are room temperature (22-23° C.) and all pressures are standard pressure (˜760 mm/Hg).
Unless otherwise indicated, any term containing parentheses refers, alternatively, to the whole term as if no parentheses were present and the term without them, and combinations of each alternative. Thus, the term “(m)ethane” refers to methane, ethane, or mixtures thereof.