Octane 1-butene conversion

Lowering reaction temperature, the selectivity to saturate octanes was highly increased reaching the value of 94%, while butene conversion remains complete. Selectivity to trimethylpentanes reaches very high values (always >85%). 

It is advantageous to pretreat butene feeds before alkylation.294-298 1,3-Butadiene is usually hydrogenated (to butenes or butane) since it causes increased acid consumption. The additional benefit of this process is that under hydrogenation conditions alkene isomerization (hydroisomerization) takes place, too. Isomerization, or the transformation of 1-butene to 2-butenes, is really attractive for HF alkylation since 2-butenes give better alkylate (higher octane number) in HF-cata-lyzed alkylation. Excessive 1,3-butadiene conversion, therefore, ensuring 70-80% isomerization, is carried out for HF alkylation. In contrast, approximately 20% isomerization is required at lower butadiene conversion for alkylation with H2SO4. 

Most processes for separating individual species from petroleum involve use of refined engineering methods, with distillation and selective adsorption the most important. Once separated, however, most materials then undergo chemical conversion into more desirable products. Alkylation involving propene and butenes yields C6 to C8 hydrocarbons for high-octane gasoline. Propylene becomes polypropylene, propylamine, or propylene glycol and ethers. 

Figure 2 presents ethylene conversion at 250 C as a function of thermal pretreatment given to a sample at different temperatures. In case of both the ZSM-5 (Si/Al=40,80) samples used in this study, the ethylene conversion was affected only marginally when the san )le pretreatment temperature was in range 300-700 C (curves a,b. Fig. 2). On the contrary, the catalytic activity of HZSM-5 sample showed an increase with the rise in pretreatment temperature from 300 to 700°C (Fig. 2c). Further rise in the pretreatment temperature to 900°C resulted in the reduced activity of all the three zeolite samples. The product distribution showed a significant change as a function of pretreatment in the case of HZSM-5 zeolite while the effect was only marginal for the improtonated ZSM-5 sample. These data are shown in Fig.3. As seen in Fig.3, the rise in the pretreatment temperature to 700°C resulted in the progressively reduced yields of C3-C5 hydrocarbons (particularly propene, butane, butene, pentene, hexene and benzene) whereas the selectivity for C7-C8 hydrocarbons (methyl cyclohexene, toluene, octane and octene) increased significantly. No such change in the selectivity was observed in the case of improtonated ZSM-5 samples(Fig. 3b).

Cj olefmic components find fewer applications than the C4 compounds. The main applications concern isoamylenes with a tertiary carbon atom, ix. essentially 2-methyl butenes, which produce isoprene by dehydrogenation and Ter Amyl Methyl Ether (TAME) by etherification. The fust conversion is discussed in detail in Section 6. As for the second its value, like that of MTBE, is associated with the antiknock properties of TAME which make it an excellent octane promoter for gasolines. By cracking, the ether can even reproduce isoamylenes. This operation offers one means of separating 2-metbyl butenes and a method that is likely to be more economic than direct extraction to obtain isoprene. 

The obtainable dimers from oligomerization of propene and butene, such as hexenes and octenes are particularly useful for conversion by the well-known oxo alcohol process into the corresponding heptyl and nonyl alcohols which may be used in the production of plasticizers, lubricating oil additives, detergents, defoamers, and similar produets. Dimers of propene are even used to improve octane rating in gasoline. 

Catalyst Molar BPO4/ AICI3 Ratio Conversion of 2-Butene, % Cs- Cs C9+ Octane Number... 

Stamicarbon BV COMPACT solution process, single proprietary Ziegler-Natta type catalyst, comonomers propylene, butene, octane, or combination. Ethylene conversion exceeds 95%, low residence time, total capacity 650 MMT/y. PE of any density (density 900-970 kg/m ) MFI = 0.8-100 g/10 min for film, injection moulding, pipes, rotomoulding, and extrusion applications crosslinking. 

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