Propylur Process

The reaction is of great value and most of the early work in the field is quoted and discussed in [203] by Block. As the allyl vinyl sulfide can be metallated and submitted to electrophilic substitution prior to rearrangement and the thiocarbonyl group hydrolysed in situ to a carbonyl group in the reaction product, the process has found considerable utility. The syntheses of propylure [488] and ris-jasmone [489] are early examples in which a thioaldehyde was intermediary formed (Y = H). A thioketone was involved [490] in the rearrangement of the allyl allenyl sulfide shown here. 

Fig. 12.17 C5-C7 olefin cracking with the Lurgi Propylur process...

Propylur A process for converting C4 and C5 hydrocarbons to propylene, using ZSM-5 catalyst in the presence of steam in a fixed bed. Developed by Lurgi in 2000 and licensed exclusively to Linde. Tested on an industrial scale in BP s plant in Worringen, Germany, in 2002. 

The Propylur process converts low value light hydrocarbons enriched in olefins into petrochemicals such as propylene and is based on a shape-selective heterogeneous zeolitic catalyst of the ZSM-5 type. 

The feedstock for the Propylur process can be C4 cuts. Raffinate I, Raffinate 11 or gasoline fraction. Naturally, a feedstock with high olefin content is more favorable. Compounds such as paraffins, cycloalkanes, and aromatics are rarely converted when they pass through the reactor. The diolefm content should be limited to approximately 1.5 % in order to reduce the formation of gum and coke during the reaction. 

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