Selective Anaerobic Oxidation of Methane Enables Direct Synthesis of Methanol

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This patent discloses a novel method for directly converting methane and water into methanol and hydrogen using a two-stage catalytic process. The process relies on a catalyst composed of copper (or other transition metals) supported on materials such as zeolite. Methane reacts with the catalyst in the first stage, followed by exposure to water vapor in the second stage. Water serves as a mild oxidant, regenerating the active catalyst sites and aiding in methanol release, enabling a highly selective, energy-efficient, and oxygen-free transformation of methane—especially suitable for natural gas applications.

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• On-site conversion of natural gas (methane) at remote extraction sites to liquid methanol for easier storage and transport.
• Reduction of methane flaring and greenhouse gas emissions by converting waste methane into valuable chemicals.
• Distributed or small-scale facilities for methanol production without the need for large industrial plants.
• Generation of hydrogen as a co-product, which can be used for fuel cells or industrial processes.
• Utilization in chemical and plastics manufacturing as a direct feedstock for methanol-based production.

BenefitsContent extracted from patent full text and abstract with AI.

• High selectivity for methanol formation (>97%), minimizing unwanted byproducts.
• Avoids the need for harsh or expensive oxidants—uses water as the oxidant.
• Operates at relatively mild temperatures and pressures compared to conventional methane-to-methanol processes.
• Enables decentralized or localized methanol production (on-site or small-scale).
• Reduces the reliance on precious metal catalysts by favoring copper or other first-row transition metals.
• Simultaneous co-production of hydrogen adds value and utility to the overall process.
• Helps mitigate methane emissions, contributing to greenhouse gas reduction efforts.

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Patent Abstract

The present invention discloses a method for the conversion reaction of methane and water to methanol and hydrogen, comprising the steps of: a) providing a first gas mixture comprising methane; b) providing a promoter of the conversion reaction, said promoter comprising one or more transition metals M and/or an oxide support ZO where: M = one or more transition metals, preferably first row transition metals, preferably copper; and ZO = alumina, silica, zeolite, titania, ceria and/or a combination thereof, preferably a zeolite; c) applying a two-stage process wherein in the first stage the first gas mixture is brought into contact with the promoter and in the second stage the promoter is brought into contact with a second gas mixture comprising water. Direct functionalization of methane in natural gas remains a key challenge. The invention presents in a preferred embodiment a direct stepwise method for converting methane into methanol with high selectivity (ˆ¼97%) over a copper-containing zeolite, based on partial oxidation with water. The activation in helium at 673 Kelvin, followed by consecutive catalyst exposures to 7 bars of methane and then water at 473 K, consistently produced 0.204 mole of CH 3 OH per mole of copper in zeolite. Isotopic labeling confirmed water as the source of oxygen to regenerate the promoters (zeolite) active centers and renders methanol desorption energetically favorable. Based on in situ x-ray absorption spectroscopy, infrared spectroscopy, and density functional theory calculations, a preferred embodiment of the present invention proposes a mechanism involving methane oxidation at Cu II oxide active centers, followed by Cu I reoxidation by water with concurrent formation of hydrogen. Water acts as an oxidant for a direct selective partial oxidation of methane into methanol and hydrogen over a copper-exchanged zeolite.