US 6,552,233 B2Granted

Vanadia-titania/metal-molybdate dual catalyst bed system and process using the same for methanol oxidation to formaldehyde

AssigneesLehigh University, Georgia-Pacific Resings, Inc.

InventorsIsrael E. Wachs, Ray P. Bourne

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Abstract

A process and a catalyst reaction zone comprising one or more fixed bed reactors for oxidizing methanol in a reactant gas feed stream to formaldehyde. According to one embodiment, the process comprises introducing the reactant gas feed stream into an upstream region containing a vanadia-titania first catalyst (substantially free of a volatile MoO3 species) under oxidizing conditions to form a partially oxidized reactant gas feed stream which is then introduced under oxidizing conditions into a downstream region containing a metal molybdate second catalyst to further oxidize any residual methanol contained therein. According to another embodiment, a fixed bed reactor comprising an upstream region and a downstream region containing the aforementioned vanadia-titania and metal molybdate catalysts, respectively, is utilized to implement the inventive process to yield a product gas stream containing formaldehyde preferably at a conversion of 85% or more and a selectivity of 90% or more.

Claims24

Dependent claims

A process for oxidizing methanol to formaldehyde in a catalyst reaction zone comprising a fixed bed reactor having an inlet end, a depth, a width, a length, an upstream region, a downstream region, and an outlet end, said process comprising the steps of:

(a) introducing a reactant gas feed stream into said inlet end, wherein said reactant gas feed stream comprises methanol;
and
(b) flowing said reactant gas feed stream through said upstream region and oxidizing said methanol to said formaldehyde to yield a partially oxidized reactant gas feed stream containing formaldehyde and potentially unoxidized residual methanol;
(c) and then flowing said partially oxidized reactant gas feed stream through said downstream region and oxidizing said residual methanol to formaldehyde to yield a product gas stream,
wherein a vanadia-titania first catalyst suitable for oxidizing said methanol to said formaldehyde is distributed in said upstream region, wherein said vanadia-titania first catalyst is substantially free of volatile MoO3, and wherein a metal molybdate second catalyst suitable for oxidizing any of said residual methanol to said formaldehyde is distributed in said downstream region.

2 more elements

Dependencies are inferred from the claim text.