Method for producing butyraldehydes

A process for reducing heat load in the production of n-butanol, which comprises:

• hydroformylating propylene to form mixed butyraldehyde products,
• recovering heat from hydrogenation of n-butyraldehyde or from a condensation portion of a distillation column in which n-butanol-product is distilled,
• feeding said mixed butyraldehyde products to the distillation column equipped with a reboiling system, wherein the heat required for reboiling is the heat recovered from the hydrogenation of n-butyraldehyde or the heat recovered from the condensation portion of the distillation column in which n-butanol product is distilled,
• separating and purifying said mixed butyraldehyde products into n-butyraldehyde and isobutyraldehyde, and
• subjecting the n-butyraldehyde obtained to hydrogenation thereby producing n-butanol, wherein said heat load is reduced by operating the distillation column under such conditions that the pressure at the top of the column is within a range from 0.001-0.5 kg/cm.sup.2 G, and the pressure at the bottom of the column is within a range from 0.05-1.0 kg/cm.sup.2 G.

A process for reducing heat load in the production 2-ethylhexanol, which comprises:

• hydroformylating propylene to form mixed butyraldehyde products,
• recovering heat from hydrogenation of 2-ethylhexenal, from a condensation portion of a distillation column in which 2-ethylhexanol product is distilled or from a condensation reaction of n-butyraldehyde,
• feeding said mixed butyraldehyde products to the distillation column equipped with a reboiling system, wherein the heat required for reboiling is the heat recovered from the hydrogenation of 2-ethylhexenal, the heat recovered from the condensation portion of the distillation column in which 2-ethylhexanol product is distilled or the heat recovered from the step of the condensation reaction of n-butyraldehyde,
• separating and purifying said mixed butyraldehyde products into n-butyraldehyde and isobutyraldehyde,
• subjecting the n-butyraldehyde obtained to condensation reaction thereby preparing a condensation product, and
• subjecting the condensation product to hydrogenation thereby preparing 2-ethylhexanol, wherein said heat load is reduced by operating the distillation column under such conditions that the pressure at the top of the column is within a range from 0.01-0.5 kg/m.sup.2 G, and the pressure at the bottom of the column is within a range from 0.05-1.0 kg/cm.sup.2 G.