ACETALDEHYDE {CH3CHO} manufacturing from Ethylene by Direct Oxidation

Reaction

 

 RAW MATERIAL REQUIREMENT TO MAKE 1 METRIC TON ACETALDEHYDE

Ethylene                                               : 670 kg

Oxygen                                                : 290 std cubic meter

Hydrochloric Acid and Catalyst        : Small

Cooling Water                                      : 300 Cubic meter

Deminerlized water                            : 3 Cubic meter

Steam (200 psi, 1.4 MPa)                    : 1300 kg

Steam (66 psi, 460 kPa)                       : 300 kg

Electricity                                             : 210 KWh (754 MJ)

Ethylene 99.7% and Oxygen 99% pure is used and both are 100 psi (700 kPa) pressure, are fed into the bottom of Vertical Reactor which have Catalyst solution of undisclosed concentration.

The catalyst solution is a water of Cupric Chloride and small amount of Palladium Chloride. The reaction taking place at a pressure slightly above the atmospheric pressure.

 

During the reaction Palladium Chloride is reduces to elemental Palladium. This Palladium is reoxidized to Palladium Chloride by Cupric Chloride. The Cuprous Chloride thus formed is reoxidized to the Cupric state by Oxygen fed to the system.

The reaction is Exothermic and is controlled by evaporation. Deminerlized water is used as makeup to replenished evaporated water. The reaction forming acetaldehyde and the oxidation of the Cuprous Chloride may be carried out simultaneously or in two steps. With the two step process operating at somewhat higher pressure, Air may be used as the oxidant in the place of Oxygen. Low purity Ethylene streams may also be used. Acetaldehyde yields are the same in both processes.

In both processes the gaseous reaction mixture, containing Seam and unreacted Ethylene in addition to reaction products, goes to a water scrubber, where Acetaldehyde is removed in the solution, the overhead gases are recycled to the reactor. A side stream is bled from the recycle stream to control inert gas buildup. The bleed gas is passed to an auxiliary reactor to convert any remaining Ethylene to Acetaldehyde.

PROPERTIES

Colorless, fuming, flammable liquid with pungent, fruity odor.

Molecular Weight            : 44.05

Specific Gravity                 : 0.7791, 20 degree C/20

Weight per gallon            : 6.49 lb (20 degree C

Melting Point                     : - 123.5 degree C

Boiling Point                       : 20.9 degree C

Flash Point (open cup)   : - 40 degree C

Ignition Temperature     : 185 degree C

Vapor Density (air = 1)   : 1.52

Explosive Limits % by volume in air           : Lower 4 and Upper 57

Threshold Limit value in ppm      : 100

Solution in all proportions in water, ethanol, ether, and bezene at room temperature.

Containers & Regulations – Tank cars, tank trucks, steel drums, cylinders, tin and bottles. Acetaldehyde is classed as a flammable liquid and requires a Red DOT shipping label.