화학공학소재연구정보센터
Acetaldehyde
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원료 ethylene; oxygen
생산물 acetaldehyde
적용 To produce acetaldehyde from ethylene by direct oxidation
설명 Description: There are two variations of the process, one using oxygen and the other using air. The choice depends on local conditions such as oxygen cost, utility prices and ethylene purity.
   The process employs a catalyst solution of copper chloride containing small quantities of palladium chloride. The reactions are summarized as follows:

C2H4 + 2CuCl2 + H2O --> CH3CHO + 2HCl + 2CuCl2
2CuCl2 + 2HCl + 1/2 O2 --> 2CuCl2 + H2O

   In the reaction, palladium chloride is reduced to elemental palladium and HCl and is re-oxidized by cupric chloride. During catalyst regeneration, the cuprous chloride is re-oxidized. The reaction and regeneration steps can be conducted separately or together.

One-stage oxidation with oxygen: Ethylene and oxygen are fed into a vertical reactor (1) which is filled with catalyst solution. The reaction takes place under a slight pressure and at the boiling temperature of the aqueous solution. The reaction is exothermic by 242 kJ per mole acetaldehyde produced. This heat is removed by water evaporation, and the concentration of the catalyst solution is kept constant by means of a corresponding water supply. Acetaldehyde produced is condensed and scrubbed (2) with water from unreacted gas, which is recycled.
   Crude acetaldehyde thus obtained is separated from byproducts and water by a two-stage distillation (3, 4).

Raw materials and utilities (per 1,000 kg acetaldehyde, 95% yield):

Ethylene (min. 99.8% vol), kg      
Oxygen, Nm3
Catalyst, PdCl2, g
CuCl2 + 2H2O, g
HCl as 30% sol., kg
Water, cooling (25),m3
Water process, m3
Water deionized, m3
Steam, kg
Electric power, kWh
670
275
0.9
150
10
200
6
1.5
1,200
50
Properties in KDB
Component Names and Formula
ID 1232
Name ACETALDEHYDE
Synonyms ETHANAL, ACETIC ALDEHYDE
CAS No. 75-07-0
Formula C2H4O
CH3CHO
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