Chemical processing propene oxidation

Examples for necessary process improvements through catalyst research are the development of one-step processes for a number of bulk products like acetaldehyde and acetic acid (from ethane), phenol (from benzene), acrolein (from propane), or allyl alcohol (from acrolein). For example, allyl alcohol, a chemical which is used in the production of plasticizers, flame resistors and fungicides, can be manufactured via gas-phase acetoxylation of propene in the Hoechst [1] or Bayer process [2], isomerization of propene oxide (BASF-Wyandotte), or by technologies involving the alkaline hydrolysis of allyl chloride (Dow and Shell) thereby producing stoichiometric amounts of unavoidable by-products. However, if there is a catalyst... 

Laboratory studies have indicated an increasing number of further processes for which iron oxides may be used as catalysts. A sodium promoted iron oxide on a support of Si02 catalyses the gas phase oxidation (377-427 °C) by nitrous oxide, of pro-pene to propene oxide (Duma and Honicke, 2000). Ferrihydrite or akaganeite can be used to catalyse the reduction (at 55-75 °C) by hydrazine, of aromatic nitro compounds to aromatic amines (which are the starting materials for a huge range of chemicals) these Fe oxides have the potential to provide a safe and economical pathway to the production of these important organics (Lauwiner et al., 1998). 

Oxidation is extremely important both from a scientific and a practical point of view. Without oxidation life would not exist. In the chemical industry, too, oxidation is probably the most important process. A major example is the combustion of fossil fuels. This process is usually uncatalyzed, but sophisticated catalytic processes do exist. Examples in the inorganic industry are the oxidation of sulphur dioxide and ammonia in the manufacture of sulphuric acid and nitric acid, respectively. In the petrochemical industry many catalytic synthesis processes are carried out, for example the production of ethylene and propene epoxide, phthalic acid anhydride. An example which has recently also become important is the catalytic combustion of hydrocarbons in flue gases. Table 5.2 gives a list of examples of oxidation catalysis in industry [93]. 

The industrial process for propene oxide manufacture is commonly referred to as the HPPO (hydrogen peroxide propene oxide) process. EniChem set up a prototype plant in 2002 [150]. BASF/Dow Chemicals and Degussa, in turn, have the construction of commercial plants already in progress or at the planning stage [151]. 

The integration of propene oxide and hydrogen peroxide processes appears, from a short-term perspective, a more realistic approach than in situ generation. It is also favored by the location of both facilities at the same chemical site. Basically, process integration envisages a simplification of H2O2 recovery that can even... 

Economic Importance. Calcium chloride is produced in large quantities as a byproduct in different chemical processes e.g. in the Solvay process or in the production of propene oxide in the chlorohydrin process, of which only a small part is processed to pure calcium chloride. In 1993 in the USA ca. 0.48 10 t (as anhydrous calcium chloride/ was produced mainly from natural sources (mainly subterranean brines and, to a lesser extent, dried out salt lakes in California). 

Propene oxide (PO, lUPAC nomenclature 2-methyloxirane) is an important chemical feedstock, having a world annual production capacity of about 7 mUhon tons [1]. It is processed into the major products, polyurethane polyols and propylene glycol [2]. The former are used in the manufacture of polyurethane foams and the latter for antifreeze (safer than ethylene glycol), drugs, cosmetics etc. 

The fact that gold is active under very mild conditions means that its potential as a selective oxidation catalyst is high, and many selective oxidation processes are important in the chemical industry [1,2]. Papers have been published on the selective oxidation of propene to propene oxide in the presence of hydrogen, oxidation of sugars and aldehydes to acids, and the oxidation of alcohols and other hydroxyl-compounds. Au-Pd catalysts have been used to oxidize ethene to vinyl acetate in the presence of acetic acid and oxygen and this is a process used by a number of manufacturers worldwide. The selective oxidation of hydrogen to hydrogen peroxide, rather than water, is also catalyzed efficiently by supported Au-Pd catalysts [49]. 

PROPENE The major use of propene is in the produc tion of polypropylene Two other propene derived organic chemicals acrylonitrile and propylene oxide are also starting materials for polymer synthesis Acrylonitrile is used to make acrylic fibers (see Table 6 5) and propylene oxide is one component in the preparation of polyurethane polymers Cumene itself has no direct uses but rather serves as the starting material in a process that yields two valuable indus trial chemicals acetone and phenol... 

The first variant works with isobutane as the hydroperoxide precursor, which is oxidized to TBHP by molecular oxygen. During the epoxidation of propene, TBHP is transformed to ferf-butanol, which is converted to methyl ferf-butyl ether. The second procedure employs ethylbenzene, which is oxidized by molecular oxygen to phenyl ethyl hydroperoxide, which transfers an oxygen to propene and so is reduced to phenylethanol. This by-product of the process is converted to styrene, a versatile bulk chemical. 

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