Synthesis of Cumene

10 member ring 5.6 X 5.3 nm pore size tridimensional pore structure 

The reaction pathway of benzene alkylation with propylene catalyzed by acids is very similar to that already reported for EB. The main difference is represented by the tendency of cumene to isomerize to n-propylbenzene, which is thermodynamically more stable at increased temperature. Also, cumene can undergo further alkylation to diisopropylbenzene (DIPB), which could be recovered by transalkylation with benzene to give cumene. The transalkylation reaction requires a higher temperature than the related alkylation. In addition, not all of the alkylation catalysts are suitable for transalkylation. Beta or dealuminated mordenite are suitable catalysts for transalkylation. The first industrial demonstrations of cumene technologies based on zeolite catalysts were started-up in 1996 by Mobil-Raytheon, EniChem and UOP, independently. In 2001, worldwide, 14 cumene units were already operating with zeolite catalysts. Around 98% ofcumene is used to produce phenol and expected world production of cumene in 2008 is around 9 million tons. For cumene, among the 40 units in the world (2004), 14 cumene plants were in operation with zeolite catalysts [222]. Today over 70% of cumene plants use a zeolite as the catalyst. 

This example shows that the problem of avoiding liquid acid waste was already solved for cumene synthesis using supported phosphoric acid, but the main problems were (i) the loss of H3PO4, which also causes problems of corrosion and deactivation, (ii) the impossibility of regeneration of the catalyst due to the type of carbon-species that accumulate on it and (iii) the formation of relatively high amounts of diisopropylbenzene (3.0-3.5%), which, even if converted by trans- 

This example evidences that the change to more sustainable technologies is a complex problem in which various factors -not only the availability of new technologies - determine the possibility of success. 

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The problem of separating the catalyst at the end of the operation can be eased in some cases by attaching the catalyst to a solid support, for instance, liquid phosphoric add in the pores of a solid carrier for the vapor phase synthesis of cumene and the fairly wide application of enzymes that are attached (immobilized) by... 

The most important autoxidation used industrially is the synthesis of cumene hydroperoxide from cumene and air (i.e., diluted oxygen) (Figure 1.37). It is initiated by catalytic amounts of dibenzoyl peroxide as the radical initiator (cf. Figure 1.11). The cumyl radical is produced... 

Fig. 1.35. Industrial synthesis of cumene hydroperoxide. In terms of Figure 1.2, this reaction is classified as a "substitution including an addition."...

Autoxidation of cumene (2.61) is the most important industrial synthesis of cumene hydroperoxide (2.62), which gives phenol and acetone. 

Oxidation of organic molecules with O2 (flameless) is referred to as autoxidation. The synthesis of cumene hydroperoxide from cumene is initiated by catalytic amounts of 2.36 as the radical initiator, which generates the cumyl radical A. The cumyl radical A reacts with O2 to give the radical B in the first propagation step and regenerated in the second propagation step, in which cumene hydroperoxide (2.62) is also formed (Scheme 2.48). 

ProUem 24.4 Outline a synthesis of cumene from cheap, readily available hydrocarbons. 

Multibed unit with interstage injection of temperature controlled process fluid or inert fluid for temperature control of the process. In the synthesis of cumene from propylene and benzene in the presence of supported phosphoric add catalyst, interstage injection of cold process gas and water is used for temperature control and maintenance of catalyst activity (Figure 13.18(g)). Autothermal multitubular unit with heat interchange between feed on the shell side and reacting gas in the packed tubes and between feed and reacted gas in an external or built-in... 

Traditionally, the synthesis of cumene has involved the use of phosphoric acid (H3P04) as a catalyst. That process results in the release of harmful by-products into the environment, and a new process that uses... 

Synthesis of Cumene (Isopropylbenzene) from Diisopropylbenzenes in the presence of Benzene using Triflic acid as catalyst at room temperature... 

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