Octenes, cracking

Natural mbber comes generally from southeast Asia. Synthetic mbbers are produced from monomers obtained from the cracking and refining of petroleum (qv). The most common monomers are styrene, butadiene, isobutylene, isoprene, ethylene, propylene, and acrylonitrile. There are numerous others for specialty elastomers which include acryUcs, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin, ethylene—acryUc, ethylene octene mbber, ethylene—propylene mbber, fluoroelastomers, polynorbomene, polysulftdes, siUcone, thermoplastic elastomers, urethanes, and ethylene—vinyl acetate. 

Krissmann J, Rattger D, Borgmann C, Kamper K, Nierlich F, Kaizik A, Knipenberg U, Malzkom R (2005) Method for producing 1-octene from crack-C4. WO 2005/000772... 

The kinetic expressions derived by Antipina and Frost have general applicability to monomolecular heterogeneous catalytic reactions which occur on a uniform surface. The expression can be made to describe the cracking of synthin or decomposition of octene over silica-alumina as well as hydrogen disproportionation of gasoline and cracking of gas oils over the silica-alumina. Numerous other applications are discussed. 

Should MTBE be banned, what would be the logical replacement(s) There are several options available. Several refiners opted to build MTBE capacity and avoid purchasing the ether on the open market. MTBE units were an option to use the facility s isobutylenes. Several licensed processes can be used to convert existing MTBE units. Kvaerner and Lyondell Chemical Co. offer technologies to convert an MTBE unit to produce iso-octane, as shown in Fig. 18.27.12 Snamprogetti SpA and CDTECH also have an iso-octene/iso-octane process. These processes can use various feedstocks such as pure iso-butane, steam-cracked C4 raffinate, 50/50 iso-butane/iso-butene feeds, and FCC butane-butane streams. The process selectively dimerizes C4 olefins to iso-octene and then hydrogenates the iso-octene (di-iso-butene) into iso-octane. The processes were developed to provide an alternative to MTBE. The dimerization reactor uses a catalyst similar to that for MTBE processes thus, the MTBE reactor can easily be converted to... 

In this case, the endothermicities of Reactions A-3 and A-4 are not equal since Reaction A-3 produces an allyl ladical. Therefore, one would expect Reaction A-3 to be somewhat faster than Reaction A—4. If Radicals I and II are present in equal concentrations, then the yield of nonene from the hydrogen-abstraction path is between one and two times the yield of octene. The nonene in excess of this is formed by the retro-ene reaction. This defines a range of importance for the molecular path and by difference the contribution of the hydrogen abstraction path. This procedure is illustrated for the dodecene cracking yields from column two of Table II. 

The lower C4-C8 a-olefins are mainly used as comonomers [8]. Small amounts of up to 3 % a-olefms are used to produce high-density polyethylene (HOPE) with a higher stress/crack resistance [9] and a slightly reduced density (0.959-0.938 g/cm ) compared with the homopolymer (0.965. 955 g/cm ). Higher quantities of 4-12% a-olefins are added to produce linear low-density polyethylene (LLDPE) with considerably reduced density (0.935-0.915 g/cm ), for which 1-butene and 1-hexene are preferred in the gas-phase process and 1-octene in the liquid phase [10]. 

Figure 3. Temperature-dependent molar hydrogen to carbon ratios for cracking catalysts coked with 1-octene at 300,4(X), 5(X) and 600 °C, and for the industrial spent cracking catalyst.

P G Smimiotis, E. Ruckenstein. Comparison of the Performance of ZSM-5, b-Zeolite, Y, USY and Their Composites in the Catalytic Cracking of n-Octane, 2,2,4-Trimethylpentane and 1-Octene. Industrial Engineering Chemistry Research, Vol. 33, 800-813, 1994. 

TABLE 9 Products from the cracking and isomerization of l-octene/H2/H20 at 300°C... 

Comparison with other molecular sieves (Fig. 11) shows that the yields obtained with FER are very high indeed. As elaborated upon elsewhere [6-8], we have proposed that the isomerisation involves a bi-molecular mechanism in which e.g. di-methylhexene isomers crack selectively to isobutene and n-butene (Fig. 12). The mono-molecular mechanism requires the energetically unfavourable primary carbenium ions. Molecular modelling [7] has provided support for this mechanism in that the branched octenes can be formed in the intra-crystalline voids of FER but their diffusion out of the pores is hindered. 

Catalyst deactivation during catalytic cracking of n-octane, isooctane and 1-octene over USHY zeolite at mild conditions and short times on stream... 

Aim of this work is to study the influence of the reactant on the coking process and the catalyst deactivation, as well as the product distributions. Therefore, the cracking of n-octane, isooctane and 1-octene was investigated in a fixed bed reactor, over USHY zeolite (0.5gr), at a range of temperatures, with two different reactant mole fi actions in the feed stream, and 20 min. time on stream. 

The cracking of 1-octene yields as the primary product isobutane. What is different comparing the cracking of 1-octene with that of n-octane and isooctane is the very high conversion rates, wdiich are followed throughout the 20 minutes of TOS allowed, with peak... 

Antdysis of Liquid Product from Catalytic Cracking of n-Octenes... 

The decomposition of highly branched octenes (Greensfelder and Voge, 13) occurs even more readily than that of the normal octenes. Thus, a mixture of 2,4,4-trimethyl-l-pentene and 2,4,4-trimethyl-2-pentene gave 63 per cent gas, the major constituent being isobutylene. Triisobutylenes are even more susceptible to catalytic cracking and extensive decomposition takes place at 360°C. at a space velocity of 2.9. 

LLDPE is a substantially linear polymer with numerous short branches, primarily made by copolymerization of ethylene (C2) with short-chain alpha-olefins (e.g., 1-butene, 1-hexene, or 1-octene, i.e., C4, Ce, or Cg). LLDPE is more difficult to process than LDPE, but it has higher modulus, strength, impact, and puncture resistance than LDPE and better environmental stress cracking resistance (ESCR). Thinner films of LLDPE replace those of LDPE in packaging applications. 

From a qualitative viewpoint, the decay behavior of sulfated zirconia, and in general of sulfated transition metal oxides, is quite similar to that previously described for zeolites and other solid acids. During the initial decline in olefin conversion, a sharp increase in the concentration of Cg products occurs as a consequence of cracking suppression, followed by a rapid decrease in TMP within the Cg fraction and the concomitant increase in octenes. This trend indicates that the acid sites responsible for cracking are the first to be poisoned, followed by... 

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