Davy Mckee (london) Limited

Andrew G Hiles

Michael W Tuck

John E Logsdon

John W Kippax

Michael W Bradley

Process for preparing tetrahydrofuran

Hydrogenation process

A continuous multi-stage hydrogenation process is described. This is effected in at least three catalytic stages connected in series. All stages up to and including the penultimate stage are operated adiabatically and in the vapor phase. Aldehyde (or other unsaturated organic compound) is fed to all stages up to and including the penultimate stage. The rate of supply of the aldehyde or other unsaturated organic compound to the penultimate stage is controlled in relation to the catalyst volume in the penultimate catalytic stage so that the degree of hydrogenation in that stage is less than 100%. The remaining chemically unsaturated material in the product mixture from the penultimate stage is hydrogenated, after cooling that product mixture, in the final catalytic stage to produce a substantially completely hydrogenated product mixture. In this way the dwell time of the reactants and product(s) at 'hot spot' temperatures is minimized, thus reducing byproduct formation.

A multi-stage hydrogenation process for hydrogenating a vaporous aldehyde to a corresponding alcohol utilizing a plurality of adiabatic catalytic stages is described. Hydrogenation is allowed to occur substantially completely and adiabatically in each stage. Further vaporous aldehyde or a mixture of hydrogen and vaporous aldehyde is added to the essentially aldehyde-free mixture exiting each catalytic stage prior to entry to the next stage.

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Pinner, United Kingdom

Andrew G Hiles