Hydrogen peroxide to propylene oxide

Fig. 14 Hydrogen peroxide to propylene oxide (HPPO) process...

CO is derived from a variety of feedstocks such as petroleum gas, fuel oil, coal, and biomass. The industrial scale production of PO starts from propylene, which is mainly obtained from crude oil. However, due to the high importance of this compound, many pathways from renewable sources have additionally been developed [54]. PP is converted to PO by either hydrochlorination or oxidation [55]. The use of chlorine leads to large amounts of salts as by-products, therefore oxidation methods are more important, such as the co-oxidation of PP using ethylbenzene or isobutene in the presence of air and a catalyst. However, this process is economically dependent on the market share of these by-products, thus new procedures without significant amounts of other side-products have been developed, such as the HPPO (hydrogen peroxide to propylene oxide) process in which propylene is oxidized with hydrogen peroxide to give PO and water [56, 57] (Fig. 14). 

The world-scale plant, has a nameplate capacity of 390 kilotons per year (KTA) of PO via the hydrogen peroxide to propylene oxide (HPPO) technology. For more information, visit www.dow.com. 

In 2008, BASF and Dow Chemical successfully started the first commercial production plant based on the novel hydrogen peroxide to propylene oxide (HPPO) process. The plant is located in Antwerp, Belgium and the initial annual capacity is around 300 000 tons. A second plant based on this technology will start production in 2011 in Map Ta Phut, Thailand. 

For the experiment with Reactor III, hydrogen peroxide once formed by oxidative dehydrogenation seems hardly decomposed further. Since the hydrogen peroxide to propylene ratio is nearly equal to unity, Seme-novs stoichiometry probably applies ... 

In 2008, Dow and BASF successfully started up the first commercial-scale production plant based on the novel BASF/Dow-developed HPPO (hydrogen peroxide for propylene oxide) technology at BASF s Antwerp, Belgium, facility. A second plant based on this technology was scheduled to begin production in Map Ta Phut, Thailand, in 2011. The two companies reported that, compared with traditional technologies, the epoxidation with hydrogen peroxide has a very low environmental impact, a simpler process layout and reduced investment costs. 

A particularly interesting system for the epoxidation of propylene to propylene oxide, working under pseudo-heterogeneous conditions, was reported by Zuwei and coworkers [61]. The catalyst, which was based on the Venturello anion combined with long-chained alkylpyridinium cations, showed unique solubility properties. I11 the presence of hydrogen peroxide the catalyst was fully soluble in the solvent, a 4 3 mixture of toluene and tributyl phosphate, but when no more oxidant was left, the tungsten catalyst precipitated and could simply be removed from the... 

In the peracid process (Bayer-Degussa technology916) propionic acid is oxidized by hydrogen peroxide in the presence of H2S04 to yield perpropionic acid, which, in turn, is used to oxidize propylene to propylene oxide. The peracetic acid process (Daicel technology ) employs a mixture of acetaldehyde, ethyl acetate, and... 

The key to the success of the oxidation examples cited above is the ability of the catalysts used to exert proper kinetic control on the possible side reactions. Without it, thermodynamically favorable but undesired products such as CO2 and H2O are made instead. Controlling oxidation kinetics to stop at the desired oxygenated products is quite difficult, and has yet to be solved for many other systems. For instance, although many attempts have been made to develop a commercial process for the oxidation of propylene to propylene oxide, both the activity and the selectivity of the systems proposed to date, mostly based on silver catalysts, are still too low to be of industrial interest " propylene oxide is presently manufactured by processes based on chlorohydrin or hydrogen peroxide instead. In spite of these difficulties, though, recent advances in selective liquid phase oxidation of fine chemicals on supported metal catalysts have shown some promise, offering high yields (close to 100%) under mild reaction conditions." ... 

The primary use for the titanium silicalites is as shape selective catalysts for hydrogen peroxide oxidations. " Propylene is converted to propylene oxide at greater than 98% selectivity and 99% peroxide conversion at 50°C over TS-1. 2,97 Butadiene is oxidized to the monoepoxide (Eqn. 10.26), also in high selectivity, and primary alcohols are oxidized to the aldehydes in all cases with selectivites greater than 80%.97... 

Numerous other large-volume compounds can be made from ethylene and propylene by standard petrochemical methods. Ethylene can be oxidized to ethylene oxide using oxygen with a silver catalyst (12.4). Propylene can be oxidized to propylene oxide with hydrogen peroxide and titanium silicalite (see Chap. 4). Vinyl chloride (a carcinogen) is produced by adding chlorine to ethylene, followed by... 

Finally, titanium silicates have also been extensively investigated for the epoxida-tion of olefins. The reaction of ethylene over a silver-supported catalyst to ethylene oxide is one of the few large-scale industrial oxidation reactions with molecular oxygen as the oxidant. Numerous studies have shown TS-1 to be effective at selectively forming propylene oxide (PO) from propylene using hydrogen peroxide as the oxidant. This is a more environmentally friendly route to PO than the currently used chlorhydrin route, and it is likely that this process will see commercialization in the near future. 

Epoxidation of propylene to propylene oxide with hydrogen peroxide... 

Ishii, Y., Yamawaki, K., Ura, T., et al. (1988). Hydrogen Peroxide Oxidation Catalyzed by Heteropoly Acids Combined with Cetylpyridinium Chloride. Epoxidation of Olefins And Allylic Alcohols, Ketonization of Alcohols and Diols, and Oxidative Cleavage of 1,2-Diols and Olefins, J. Org. Chem., 53, pp. 3587-3593 Sato, K., Aoki, M., Ogawa, M., et al. (1997). A Halide-Free Method for Olefin Epoxidation with 30% Hydrogen Peroxide, Bull. Chem. Soc. Jpn., 70, pp. 905-915 Xi, Z. W., Zhou, N., Sun, Y., et al. (2001). Reaction-Controlled Phase-Transfer Catalysis for Propylene Epoxidation to Propylene Oxide, Science, 292, pp. 1139-1141 Neumann, R. 

The most widely used industrial routes to propylene oxide (PO) are based on the chlorohydrin process or hydroperoxide methods. Much attention has also been directed to processes performed in the presence of hydrogen peroxide in the liquid phase with a TS-1 molecular sieve as the catalyst, iron complexes accommodated in amorphous SBA-15 and MCM-41 modified with alkaline metal salts, and SBA-3 mesoporous molecular sieves doped with transition metal ions (Fe, V, Nb, and Ta). 

---