dehyde can be obtained by catalytic dehydrogenation of :

This is analogous to the manufacture of formaldehyde from methanol . However, in contrast to methanol manufacture, oxidation is not used as an alternative. Instead, two modifications of the dehydrogenation are customary:
1. Dehydrogenation on silver, or preferably copper, catalysts
2. Oxidative dehydrogenation with silver catalysts in the resence of oxygen.

To 1: 
 
The dehydrogenation of ethanol is usually done over Cu-catalysts activated with Zn, Co, or Cr. One frequently applied process originates from the Carbide & Corporation.

The temperature is regulated to 270-300 °C so that the ethanol conversion is limited to 30-50%. A selectivity to of 90-95 % is attained. Byproducts include crotonaldehyde, ethyl acetate, higher alcohols, and ethylene. The hydrogen formed is pure enough to be used directly for hydrogenation.

To 2:

If the dehydrogenation of ethanol is conducted in the presence of air or oxygen (e.g., the Veba process), the concomitant combustion of the hydrogen formed supplies the necessary heat of dehydrogenation (oxidative dehydrogenation or autothermal dehydrogenation):

In the industrial process, silver catalysts in the form of wire gauzes or bulk crystals are preferred. Ethanol vapors mixed with air at 3 bar and at 450-550°C are passed over the catalyst. The reaction temperature is contingent upon the amount of air used; a temperature is reached at which the heat of oxidation and heat consumption of the dehydrogenation compensate one another.

Depending on the reaction temperature, 30-50% of the ethanol is converted per pass with a selectivity of 85-95%. The byproducts are acetic acid, formic acid, ethyl acetate, CO and CO₂.

In both process modifications, the acetaldehyde is separated from the unreacted alcohol and byproducts and purified in various washes and distillations. The recovered ethanol is recycled to the reaction.