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US 4,967,014 AGranted
Process for producing formaldehyde and derivatives thereof
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsJunzo Masamoto, Junzo Ohtake, Mamoru Kawamura
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Abstract
A process for formaldehyde production is disclosed comprising the steps of reacting methanol with formaldehyde to form methylal and then oxidizing the resulting methylal to obtain formaldehyde. Formaldehyde derivatives may also be produced. A dilute formaldehyde solution resulting from recovery of the product is recycled and used as feed material for the initial reaction step.
Claims17
A process for producing formaldehyde or a derivative thereof from methanol, comprising the steps of:
- (i) heating methanol and formaldehyde in aqueous solution in the presence of an acidic catalyst to obtain methylal;
- (ii) oxidizing the resulting methylal using oxygen as an oxidizing agent in the presence of an oxide containing as effective components iron and molybdenum, or an oxide containing as effective components iron, molybdenum and at least one metal element selected from the group consisting of alkali metals, bismuth, chromium, tungsten, cobalt and nickel to obtain a formaldehyde gas;
- (iii) absorbing the formaldehyde gas resulting from the oxidation reaction into water or into an aqueous formaldehyde solution to obtain an aqueous formaldehyde solution;
- (iv) separating the aqueous formaldehyde solution obtained in step (iii) into formaldehyde of a lower water content and formaldehyde of a higher water content;
- and
- (v) returning the water-rich formaldehyde separated in step (iv) to step (i) for further use as the formaldehyde component, wherein said derivative of formaldehyde is selected from trioxane, paraformaldehyde, the condensation product of urea and formaldehyde and the condensation product of phenol and formaldehyde.
3 more elements
A process for producing formaldehyde or a derivative thereof from methanol, comprising the steps of:
- (i) heating methanol and formaldehyde in aqueous solution in the presence of an acidic catalyst to obtain methylal;
- (ii) oxidizing the resulting methylal using oxygen as an oxidizing agent in the presence of an oxide containing as effective components iron and molybdenum, or an oxide containing as effective components iron, molybdenum and at least one metal element selected from the group consisting of alkali metals, bismuth, chromium, tungsten, cobalt and nickel to obtain a formaldehyde gas;
- (iii) absorbing the formaldehyde gas resulting from the oxidation reaction into water or into an aqueous formaldehyde solution to obtain an aqueous formaldehyde solution;
- (iv) reacting the aqueous formaldehyde solution to form a derivative of formaldehyde, separating said derivative from unreacted water-rich formaldehyde, and recovering said derivative;
- and
- (v) returning the water-rich formaldehyde separated in step (iv) to step (i) for further use as the formaldehyde component, wherein said derivative of formaldehyde is selected from trioxane, paraformaldehyde and the condensation product of phenol and formaldehyde.
3 more elements
A process for producing formaldehyde or a derivative thereof from methanol, comprising the steps of:
- (i) heating methanol and formaldehyde in aqueous solution in the presence of an acidic catalyst to obtain methylal;
- (ii) oxidizing the resulting methylal using oxygen as an oxidizing agent in the presence of an oxide containing as effective components iron and molybdenum, or an oxide containing as effective components iron, molybdenum and at least one metal element selected from the group consisting of alkali metals, bismuth, chromium, tungsten, cobalt and nickel to obtain a formaldehyde gas,
- (iii) absorbing the formaldehyde gas resulting from the oxidation reaction into water or into an aqueous formaldehyde solution to obtain an aqueous formaldehyde solution;
- (iv) concurrently separating a portion of the aqueous formaldehyde solution obtained in step (iii) into formaldehyde of a lower water content and formaldehyde of a higher water content, and reacting the remaining portion of the aqueous formaldehyde solution to form a derivative of formaldehyde, separating said derivative from unreacted water-rich formaldehyde, and recovering said derivative;
- and
- (v) returning the water-rich formaldehyde separated in step (iv) to step (i) for further use as the formaldehyde component, wherein said derivative of formaldehyde is selected from trioxane, paraformaldehyde and the condensation product of phenol and formaldehyde.
3 more elements
Dependencies are inferred from the claim text.