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Unsaturated C4 hydrocarbons are abundant in various petrochemical streams. They can be considered as a potential feedstock for the steam-cracking process, where they must be co-processed with C6 and higher (C6+) hydrocarbons of primary naphtha fractions. Co-pyrolysis experiments aiming at the comparison of different C4 hydrocarbon performances were carried out in a laboratory micro-pyrolysis reactor under standardized conditions: 820 °C, 400 kPa, and 0.2 s residence time in the reaction zone. C4 hydrocarbons were co-pyrolyzed with different co-pyrolysis partners containing longer hydrocarbon chain to study the influence of the co-pyrolysis partner structure on the behavior of C4 hydrocarbons. The yields of the pyrolysis products and the conversion of C4 hydrocarbons were used as the performance factors. A regression model was developed and used as a valuable tool for quantifying the inhibition or acceleration effect of co-pyrolysis on the conversion of co-pyrolyzed hydrocarbons. It was found that the performance of different C4 hydrocarbons in co-pyrolysis is substantially different from the separate pyrolysis of the individual components. [ABSTRACT FROM AUTHOR]

A brief analysis is performed for the current state of processes for the production of motor fuels based on the consecutive oligomerization and hydrogenation reactions of unsaturated hydrocarbons. Some new butene hydrooligomerization catalysts based on the bifunctional NiO/ВO-AlO, PdO/ВO-AlO, and MoO/ВO-AlO systems are considered. It is shown that the best process performance parameters (a 67 wt % yield of liquid С products at a butene conversion of more than 90%) are achieved with PdO/ВO-AlO catalyst prereduced in a hydrogen medium. The possibility of acetylene hydrooligomerization on NiO/BO-AlO catalyst is demonstrated in principle. It is established that the presence of nickel(II) cations chemically bonded to the surface of a support is of fundamental importance for both acetylene hydrooligomerization and ethylene oligomerization. [ABSTRACT FROM AUTHOR]

The oxidative dehydrogenation of a 1-butene/trans-butene (1:1) mixture to 1,3-butadiene was carried out in a two-zone fluidized bed reactor using a Mo-V-MgO and a γ-Bi2MoO6 catalyst. The significant operating conditions temperature, oxygen/butene molar ratio, butene inlet height, and flow velocity were varied to gain high 1,3-butadiene selectivity and yield. Furthermore, axial concentration profiles were measured inside the fluidized bed to gain insight into the reaction network in the two zones. For optimized conditions and with a suitable catalyst, the two-zone fluidized bed reactor makes catalyst regeneration and catalytic reaction possible in a single vessel. In the lower part of the fluidized bed, the oxidation of coke deposits on the catalyst as well as the filling of oxygen vacancies in the lattice can occur. The oxidative dehydrogenation reaction takes place in the upper zone. Thorough particle mixing inside fluidized beds causes permanent particle exchange between both zones. © 2016 American Institute of Chemical Engineers AIChE J, 63: 43-50, 2017 [ABSTRACT FROM AUTHOR]

Existing industrial technologies for the production of motor fuel compounds by the heterogeneous oligomerization of light С-С alkenes are considered, along with ones promising for the practical use. Such basic types of systems used as heterogeneous catalysts in these processes as solid phosphoric acid, amorphous alumosilicates, zeolites, ion-exchange resins, anion-modified metal oxides, and nickel-containing catalysts, are described. Special attention is given to the dimerization of iso-butylene with the formation of iso-octene and its subsequent hydrogenation to iso-octane. [ABSTRACT FROM AUTHOR]

The conversion of isobutane-butenes mixtures on the H-form of ultrastable zeolite Y and sulfated zirconia under supercritical conditions at 150-160°C and 80 atm was studied. The isobutane/C-olefins molar ratios (I/O) were 1.5, 14, and 28. In isobutane alkylation (I/O = 14 and 28), sulfated zirconia was more stable: at 150°C and 80 atm, the olefin conversion above 90% was retained for 5 h. Under the same conditions, the deactivation of the zeolite catalyst started after 1-2.5 h (depending on the initial I/O ratio). Selectivity for the formation of C hydrocarbons was 30-40%. An increase in the butene content of the initial mixture led to the domination of the dimerization of butenes over the alkylation of isobutane. [ABSTRACT FROM AUTHOR]

The possibility of using a fiber-optic densitometer to monitor the density of the reaction medium during heterogeneous catalytic reactions has been shown using the example of the alkylation of isobutane with butenes conducted under supercritical conditions at 150°C and 80 atm. The density has been measured at two points-before and after a fixed bed of an H-USY catalyst. The dependences of the density and refraction of the isobutane-butene mixture on temperature and pressure have been plotted. [ABSTRACT FROM AUTHOR]

Catalytic systems for the nonoxidative or oxidative dehydrogenation of C-C alkanes into the respective alkenes are considered. Scanty data concerning microwave activation of these processes and the potential and advantages of microwave versus conventional technologies are analyzed. [ABSTRACT FROM AUTHOR]

This review provides a technical description of the range of commercial products that can be accessed from n-butanol, with specific emphasis on n-butanol derived from renewable sources (biobutanol). n-Butanol itself and primary derivatives in which the oxygen functionality of the molecule is retained (butyraldehyde and butyric acid) have mainstream applications in the solvent, polymer, fuel oxygenate, and/or specialty chemical markets, while butanol dehydration products (butenes and butadiene) present additional opportunities in the hydrocarbon fuel and synthetic elastomers markets. The volume and value of these markets are noted and specific applications of first- and second-generation n-butanol derivatives are discussed. Selected technologies for the conversion of butenes into other valuable olefins are described and current biobutanol producers and technology providers are identified and profiled. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

In order to obtain an efficient alumina catalyst for skeleton isomerization of n-butenes with a high catalytic activity, we study the influence of hydrothermal treatment (HTT) of alumina systems at 150-200°C on the parameters of the crystalline and pore structure, and acid-base properties of industrial γ-AlO. It is shown that the HTT of aluminum hydroxide increases the sizes of microcrystallites and reduces the alumina's specific surface area and the number of acid-base centers. This reduces the activity in the reaction of skeletal isomerization of n-butenes. HTT of the two-phase alumina-aluminum hydroxide system produces smaller crystallites of γ-AlO and raises the acidity of the alumina obtained after calcination at 550°C; as a result, the catalytic activity increases. This method can be used to enhance the activity of industrial samples of alumina in the reaction of skeletal isomerization of n-butenes. [ABSTRACT FROM AUTHOR]

Pure 1-butene and 2-butenes can be efficiently obtained from butane-butene fractions by combining the positional isomerization of n-butenes on sulfonic acid cation exchanger catalysts with sharp distillation. At 50–60°C, an equilibrium 2-butenes: 1-butene ratio of ∼25: 1 is attained. The 2-butenes, which are comparatively high-boiling compounds, can be sufficiently completely separated from detrimental impurities (1,3-butadiene and isobutene), 1-butene, and isobutane by distillation. The back isomerization of the purified 2-butenes into 1-butene with continuous removal of the latter as distillate affords pure 1-butene at a relatively low cost. [ABSTRACT FROM AUTHOR]

Light olefins are the main building blocks used in the petrochemical and chemical industries for the production of different components such as polymers, synthetic fibers, rubbers, and plastic materials. Currently, steam cracking of hydrocarbons is the main technology for the production of light olefins. In steam cracking, the pyrolysis of feedstocks occurs in the cracking furnace, where hydrocarbon feed and steam are first mixed and preheated in the convection section and then enter the furnace radiation section to crack to the desired products. This paper summarizes olefin production via the steam cracking process; and the reaction mechanism and cracking furnace are also discussed. The effect of different operating parameters, including temperature, residence time, feedstock composition, and the steam-to-hydrocarbon ratio, are also reviewed. [ABSTRACT FROM AUTHOR]

Synthesis gas derived from natural gas, coal, biomass or any other hydrocarbon source can be advantageously utilized to produce propylene. The approach adopted by the current investigation carries out the conversion of syngas in two stages: single- stage dimethyl ether (DME) synthesis followed by dimethyl ether conversion. Single- stage DME synthesis is carried out in the liquid phase utilizing the synergistic' effect of dual catalysts, Cu/ZnOAl2O3 and γ-alumina. Dimethyl ether produced by this process is then converted to propylene using a shape-selective H-ZSM-5 catalyst. Very high selectivity towards propylene (as high as 68 wt%, the rest being ethylene and butenes) can be achieved In' using this cubist at appropriate reaction and feed conditions. In general, higher temperatures, low partial pressures of DME in the feed, and short contact times used over a H-ZSM-5 catalyst with low aridity increase she selectivity of DME conversion to propylene by inhibiting competing as sell as successive reactions which would otherwise form other olefins, paraffins and aromatics. This article describes at length the second stage of the overall syngas-to-propylene process, focusing on the conversion of dimethyl ether to propylene over a wide range of reaction and feed conditions. [ABSTRACT FROM AUTHOR]