Styrene monomer/propylene oxide

SMPO [styrene monomer propylene oxide] A process for making propylene oxide by the catalytic epoxidation of propylene. The catalyst contains a compound of vanadium, tungsten, molybdenum, or titanium on a silica support. Developed by Shell and operated in The Netherlands since 1978. 

Olefin epoxidation is an important industrial domain. The general approach of SOMC in this large area was to understand better the elementary steps of this reaction catalyzed by silica-supported titanium complexes, to identify precisely reaction intermediates and to explain catalyst deachvahon and titanium lixiviation that take place in the industrial Shell SMPO (styrene monomer propylene oxide) process [73]. (=SiO) Ti(OCap)4 (OCap=OR, OSiRs, OR R = hydrocarbyl) supported on MCM-41 have been evaluated as catalysts for 1-octene epoxidation by tert-butyl hydroperoxide (TBHP). Initial activity, selechvity and chemical evolution have been followed. In all cases the major product is 1,2-epoxyoctane, the diol corresponding to hydrolysis never being detected. 

Shell has coproduced propylene oxide (PO) and styrene using its proprietary styrene monomer propylene oxide (SMPO) process for three decades. Research, development, and plant trials have been performed on a continuous basis in order to improve its efficiency and cost competitiveness. We report here some of the key fundamental and technological learnings gathered over various parts of the process. 

Propylene oxide (PO) is a versatile chemical intermediate used in a wide range of industrial and commercial products. Current world production is over 6 million metric torts a year. While several processes exist, the Shell Chemicals companies have derived a strong competitive advantage by using and continually developing their proprietary styrene monomer propylene oxide (SMPO) technology, a process in which propylene and ethylbenzene (EB) are converted into PO and styrene monomer (SM), respectively. Worldwide, there are now five world-scale SMPO plants based on Shell technology, the most recent one started up in 2006 in China. 

Scheme 4.51 shows the process known to the bulk chemicals industry as SMPO, the styrene monomer-propylene oxide process. Styrene is used in polymers, and propylene oxide derivatives have a wide variety of uses, including as surfactants and in anti-freeze. For the bulk industry, the process is as follows. Addition of ethylene to benzene gives ethylbenzene, which undergoes air oxidation to give the hydroperoxide. Reaction of this with propylene, in the presence of a suitable catalyst, gives styrallyl alcohol and propylene oxide. Styrallyl alcohol is readily dehydrated to styrene. 

Aerobic selective oxidation of alkylaromatics, including cumene (CU), ethylbenzene (EtB), and cyclohexylbenzene (CyB), to the corresponding hydroperoxides (CHPs) represents a key step for several large-scale productions, including the Hock process for the synthesis of phenol (see Chapter 2) [15] and the Shell styrene monomer/propylene oxide (SM/PO) process for the production of propylene oxide (PO) and styrene monomer (SM) [16]. 

The establishment of a new downstream Styrene Monomer/Propylene Oxide (SMPO) plant by Seraya Chemicals Singapore (Private) Limited (SCSL) on nearby Pulau Seraya. 

Keywords monomers propylene oxide and styrene, selective oxidation, dioxygen, ethylbenzene, a-phenylethylhydroperoxide, nickel (II) bis (acetylacetonate), N-metylpirrolidon-2, HMPA, MSt (M=Na, K), PhOH. 

A process to produce styrene monomer and propylene oxide simultaneously was introduced in 1969. 

Monomers devoid of polar groups generally undergo anionic polymerization in a predictable manner. With polar monomers sometimes side reactions occur during the process transfer reactions in the case of acrylonitrile, or propylene oxide, and even more so with alkylacrylates deactivations (or "killing") reactions in the case of halogen substituted styrene or dienes. 

EB/SM (ethylbenzene/styrene monomer) process. Styrene can also be made by PO/SM (propylene oxide/styrene monomer) process). This process starts by oxidizing ethylbenzene (C6H5CH2CH2) to its hydroperoxide (C6H5CH(OOH)CH3), which is then used to oxidize propylene (CH3CH = CH2) to produce propylene oxide (CH3CH2CHO) and phenylethanol (C6H5CH(OH)CH3). The phenylethanol is then dehydrated to give... 

Styrene is the monomer for polystyrene and styrene-butadiene rubber. Propylene oxide is mainly used for the manufacture of propylene glycol and polyurethanes. 

POSM [Propylene Oxide Styrene Monomer] A process for making propylene oxide from ethylbenzene. The ethylbenzene is reacted with oxygen and propylene in the presence of a proprietary catalyst. Developed in Russia by JSC Nizkhnekamskneftkheim and licensed exclusively by Dow Chemical Company. In 2006, 36% of the world production of propylene oxide was made by this process. See also SMPO. 

All the styrene monomer (bpi.oia - 145.2 C, s/J == 0.906. ) produced throughout the world is obtained directly or indiiectly from etbylbenzeoe. Most is product by dehydrogenation, while a certain amount is also obtained as a co-product of Ae manu- ctuie of propylene oxide. Some attempts have been made to extract styrene from liyrolysis C5- gasolines (Stex process by Toray, deserflied in Section 4.2J), but they have. not culminated in commercial plants. 

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