Acetaldehyde, from ethylene

The industrial synthesis of acetaldehyde from ethylene IS shown on page 644... 

Pd2+ salts are useful reagents for oxidation reactions of olefins. Formation of acetaldehyde from ethylene is the typical example. Another reaction is the formation of vinyl acetate by the reaction of ethylene with acetic acid (16, 17). The reaction of acetic acid with butadiene in the presence of PdCl2 and disodium hydrogen phosphate to give butadienyl acetate was briefly reported by Stem and Spector (110). However, 1-acetoxy-2-butene (49) and 3-acetoxy-l-butene (50) were obtained by Ishii and co-workers (111) by simple 1,2- and 1,4-additions using PdCl2/CuCl2 in acetic acid-water (9 1). 

Monosubstituted and 1,2-disubstituted olefins can be oxidized to aldehydes and ketones by palladium chloride and similar salts of noble metals.367 1,1-Disubstituted olefins generally give poor results. The reaction is used industrially to prepare acetaldehyde from ethylene... 

Catalysts used to convert ethylene to vinyl acetate are closely related to those used to produce acetaldehyde from ethylene. Acetaldehyde was first produced industrially by the hydration of acetylene, but novel catalytic systems developed cooperatively by Farbwerke Hoechst and Wacker-Chemie have been used successfully to oxidize ethylene to acetaldehyde, and this process is now well established (7). However, since the largest use for acetaldehyde is as an intermediate in the production of acetic acid, the recent announcement of new processes for producing acetic acid from methanol and carbon monoxide leads one to speculate as to whether ethylene will continue to be the preferred raw material for acetaldehyde (and acetic acid). 

Production of acetaldehyde from ethylene by the Wacker process using PdCl2 and CuCl2 as catalysts. 

Production of Acetaldehyde from Ethylene by the Wacker Process... 

Uranium oxides have been investigated as catalysts and catalyst components for selective oxidation. They are more commonly used as catalyst components, but there are also reports of uranium oxide alone as a selective oxidation catalyst The oxidation of ethylene over UO3 has been studied by Idriss and Madhavaram [40] using the technique of temperature programmed desorption (TPD). Table 13.3 shows the desorption products formed during TPD after ethylene adsorption at room temperature on UO3. The production of acetaldehyde from ethylene indicates... 

The Wacker or Smidt process, used to synthesize acetaldehyde from ethylene, involves a catalytic cycle that uses PdCl4. A brief outline of a cycle proposed for this process is shown in Figure 14-17. The fourth step in this cycle is substantially more complex than that shown in the figure and has been the subject of much study. ... 

Preliminary mechanistic studies (36) on synthesizing vinyl acetate from ethylene have indicated that it probably proceeds in a manner similar to the synthesis of acetaldehyde from ethylene (19). 

Technical Applications (Wacker-Hoechst Processes) 2.4.1.4.1 Acetaldehyde from Ethylene... 

Figure 2. Acetaldehyde from ethylene, single-stage process (a) reactor, (b) separating vessel, (c) cooler, (d) scrubber, (e) crude aldehyde tank, (f) light ends distillation,...

Figure 3. Acetaldehyde from ethylene, two-stage process (a) reactor, (b) flash tower,...

The oxidation technique is applied to propylene, in the presence of pattadaun chloride and copper chloride, initially developed for the manufacture of acetaldehyde from ethylene (see Section 8.1.4). In principle, the transformation reaction comprises the formation of a complex with propylene, in the presence of palladium chloride and in hydrochloric add medium ... 

The first step is catalysed by palladium chloride and is similar to the Wacker process for manufacturing acetaldehyde from ethylene. 

With oxo synthesis, Wacker-type oxidations of alkenes is one of the older homogeneous transition-metal-catalyzed reactions [1], The most prominent example of this type of reaction is the manufacture of acetaldehyde from ethylene. This well-known reaction, which has been successfully developed on an industrial scale (Wacker process), combines the stoichiometric oxidation of ethylene by palladium ) in aqueous solution with the in situ reoxidation of palladium(O) by molecular oxygen in the presence of a copper salt (Eqs. 1 -4) [2]. 

Distillation bottoms from the production of acetaldehyde from ethylene (T)... 

The ethylene-based version of the vinyl acetate process was also developed by Wacker Chemie. The process is similar to the Wacker process for acetaldehyde from ethylene which was developed about the same time. In the vinyl acetate process, ethylene is reacted with high purity oxygen and acetic acid in the presence of a palladium chloride catalyst. National Distillers and Chemicals, which later became USI chemicals and is now a division of Quantum Chemicals, developed a similar vapor phase ethylene-based technology in the United States. Both versions of the process are presently used commercially [25,26]. 

Acetaldehyde from Ethylene and Related Wacker-Type Reactions... 

After World War II, when the big oil companies installed a large number of refineries in industriahzed countries, lower olefins, particularly ethylene, became available in large quantities. Chemical companies replaced successively their acetylene-based processes for the production of aliphatic C2, C4, and C3 compounds by much cheaper processes with ethylene as the feedstock. Researchers of the Consortium fiir elektrochemische Industrie GmbH, the research organization of Wacker Chemie GmbH, succeeded in finding a new process for the manufacture of the important industrial intermediate acetaldehyde from ethylene [1, 2]. 

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