Oligomerization Of Light Olefins Research Articles

Propylene oligomerization over SiO2-overcoated oxides

Catalytic oligomerization of light olefins is an important CC coupling strategy that can be used to produce high-value transportation fuels and chemicals from shale gas and biomass feedstocks. In this work, vapor-phase propylene oligomerization was studied over a series of overcoated SiO2-MOx materials, whose acid site densities and strengths are tunable by the amount of SiO2 deposition and the nature of the core oxide. These materials contain acid sites only on particle external surfaces, limiting pore diffusion artifacts. SiO2-MOx materials were prepared by depositing stoichiometric amounts of tetraethyl orthosilicate (TEOS) onto Al2O3, anatase TiO2, Nb2O5, and ZrO2. Compared to the unmodified oxides, which are poor propylene oligomerization catalysts, the SiO2-MOx materials exhibit moderate activity with Al2O3, TiO2, and Nb2O5 core materials performing better than commercial amorphous silica alumina (ASA) on a surface area basis. The activity of the materials appears to be primarily driven by their Brønsted acid strength as measured by 31P TMPO MAS NMR with the rates ranked in order SiO2/Al2O3 > SiO2/TiO2 ≈ SiO2/Nb2O5 > SiO2/ZrO2. This study shows that SiO2-overcoated materials are a tunable class of materials that are active for vapor-phase propylene oligomerization.

MCM-22 zeolite-based system to produce jet fuel from the 1-hexene oligomerization

The oligomerization of light olefins is an alternative for generating clean liquid fuels. In this study, the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring (10 MR) was discussed for 1-hexene oligomerization. MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization. The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite. The MCM-22 zeolite was characterized in detail by NMR, Py-FTIR, and TG analyses. The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated. Structure–activity relationships were established through the kinetic study. Although the density of strong acid sites was essential for the oligomerization of 1-hexene, the presence of low pressure was also necessary for the formation of dimers. Thus, MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.

Production and catalytic upgrading of 2,3-butanediol fermentation broth into sustainable aviation fuel blendstock and fuel properties measurement

With the increasing demand for sustainable supplies of aviation fuel and need to address climate change, new conversion technologies are needed to efficiently process biomass, produce high quality jet fuel blendstock, and meet carbon emission targets. This study demonstrates the synthesis, conditioning, and catalytic upgrading of 2,3-butanediol (BDO) fermentation broth into a jet fuel blendstock candidate. A high-titer 2,3-BDO fermentation broth (i.e., ∼90 g/L) was produced at a 100-L scale and pretreated via nanofiltration to decrease the impurities level in the broth from 4.6 to 0.6 wt%. A novel process for catalytic upgrading of aqueous 2,3-BDO into a jet fuel blendstock candidate was developed, and each step was efficiently demonstrated. The catalytic steps include 1) 2,3-BDO dehydration into methyl ethyl ketone (MEK) over AlPO4, 2)MEK conversion into olefins over Zn1Zr10Ox, 3)oligomerization of olefins over a zeolite beta, and 4) hydrogenation over platinum/carbon. Both the model feed and real 2,3-BDO fermentation broth were tested for upgrading 2,3-BDO to MEK. With the real feed, a continuous loss of conversion (i.e., >50 % loss over ∼140 h time-on-stream [TOS]) was partly attributed to reversible deactivation from coking species. However, the conversion remained stable with the model feed, which demonstrates the efficiency of the first step for converting aqueous 2,3-BDO (10 wt% in water). For upgrading MEK to olefins, high selectivity to olefins (i.e., 82.5 %) was obtained at high conversion levels (i.e., 93–98 %) with stable conditions being achieved for > 70–hours TOS. Oligomerization of light olefins, which was demonstrated for > 270 h TOS, mainly led to the formation of dimers (C8-10) and trimers (C13–14). The oligomerized product was hydrogenated and distilled to recover the jet fraction (35mass% or 40.9 % carbon based yield), which consists mostly of desired isoalkanes (31.7 wt%), n-alkanes (24.5 wt%), and cycloalkanes (29.6 wt%). While some improvement is still needed to meet ASTM D7566 specifications for viscosity and final boiling point temperature, freezing point, density, aromatics content, and sulfur content of the jet blendstock candidate were within acceptable ranges, thus highlighting the potential of this process for production of jet fuel blendstock.

Ethylene oligomerization on Ni2+ single sites within lacunary defects of Wells Dawson polyoxometalates.

Oligomerization of light olefins has become an essential step to convert gaseous olefins to liquid fuels and value-added chemicals. Here, we report the synthesis and application of nickel single sites isolated on Wells Dawson polyoxometalate defects as stable and regenerable catalysts for ethylene oligomerization.

Optimization of continuous-flow heterogeneous catalytic oligomerization of 1-butene by design of experiments and response surface methodology

Oligomerization of light olefins allows the production of clean, sulphur-free fuels or fuel additives with reduced aromatics content, and useful chemicals. Commercial heterogeneous catalytic oligomerization technologies were developed to meet market demands in flexible fashions, whereby the operating conditions may be adjusted in favor of the desired product specifications and yields. For achieving superior performances, the development of expeditious evaluation and optimization tools is important, albeit not trivial because light olefins oligomerization involves complex reaction systems and product quality depends on many factors. In this sense, the design of experiments (DoE) and response surface methodology (RSM) are valuable tools, yet unexploited for light olefins oligomerization processes. In this work, DoE/RSM models were developed and validated for the oligomerization of 1-butene – derivable from fossil or renewable sources of organic carbon – over a superior hierarchical zeotype catalyst, under high pressure, continuous flow conditions, targeting clean diesel range products. The models allowed to investigate the individual and cross effects of reaction pressure, temperature and weight hourly space velocity on conversion and yields of specific product fractions. The optimization studies also accounted for product quality features such as, reduced aromatics content; these studies counted with the analytical input of Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry (GC×GC-ToFMS) for characterizing the products. Importantly, DoE/RSM tools may contemplate not only kinetic data, but also product quality indicators, and help identify most relevant process parameters impacting on the productivity.

Oligomerization of Light Olefins Catalyzed by Brønsted-Acidic Metal–Organic Framework-808

Sulfated metal-organic framework-808 (S-MOF-808) exhibits strong Brønsted-acidic character which makes it a potential candidate for the heterogeneous acid catalysis. Here, we report the isomerization and oligomerization reactions of light olefins (C3-C6) over S-MOF-808 at relatively low temperatures and ambient pressure. Different products (dimers, isomers, and heavier oligomers) were obtained for different olefins, and effective C-C coupling was observed between isobutene and isopentene. Among the substrates investigated, facile oligomerization occurred very specifically for the structures with an α-double bond and two substituents at the second carbon atom of the main carbon chain. The possible oligomerization mechanism of light olefins was discussed based on the reactivity and selectivity trends. Moreover, the deactivation and regeneration of S-MOF-808 were investigated. The catalyst deactivates via two mechanisms which predominance depends on the substrate and reaction conditions. Above 110 °C, a loss of acidic sites was observed due to water desorption, and the deactivated catalyst could be regenerated by a simple treatment with water vapor. For C5 substrates and unsaturated ethers, the oligomers with increased molecular weight caused deactivation via blocking of the active sites, which could not be readily reversed. These findings offer the first systematic report on carbocation-mediated olefin coupling within MOFs in which the Brønsted acidity is associated with the secondary building units of the MOF itself and is not related to any guest substance hosted within its pore system.

Oligomerization of light olefins in the presence of a supported Brønsted acidic ionic liquid catalyst

Oligomerization of C4-C5 olefins and olefin mixtures has been investigated in the presence of a supported ionic liquid phase (SILP) catalyst, obtained by the physisorption of 1-(4-sulfobutyl)-3-methylimidazolium trifluoromethanesulfonate on silica. Surface properties of the SILP phase were determined from the experimental data of their nitrogen adsorption/desorption isotherms. Fresh and spent catalyst were characterised by 13C- and 29Si-CP MAS NMR spectroscopy and thermogravimetric analysis. Reactivity of alkenes followed the awaited order of isobutene>but-1-ene>pent-1-ene. The main products of oligomerization of hydrocarbon mixtures, modelling the C4-C5 fraction of waste polyethylene cracking products, were isoolefins in the boiling point range corresponding to kerosene fraction components, which is applicable as jet fuel after hydrotreatment. Stability and recyclability of the catalyst could greatly be enhanced by a pretreatment of the fresh catalyst, carrying out an oligomerization experiment with pure isobutene.

Application of Modified Clay Catalysts in Oligomerization of Light Olefins

The oligomerization of light olefins to high-octane clean engine fuels is one possible way to solve increased requirements for motor fuels. This paper presents a study of catalytic oligomerization of C 2 -C 4 olefins on Ru-Fe supported pillared clay catalyst with different metallic quantity. The prepared catalysts were characterized by X-ray diffraction, N 2 adsorption-desorption at 77K, BET and BJH methods. The BET and BJH methods showed the pillared clay had significantly increased surface area and when an appropriate amount of Ru and Fe were added, the bimetallic alloys were uniformly dispersed on the modified clay surfaces and had an average mesopore size of 4.1 nm. It is indicated that excess metal oxides blocked the surface of bimetallic RuFe/MMC system, resulted in decreased catalytic activity. The low metal content catalysts showed higher oligomerization activity and increasing the Fe content gave selectivity to isomerization reactions.

Oligomerization of light olefins over ZSM-5 and beta zeolite catalysts by modifying textural properties

The oligomerization of ethene and 1-hexene was performed under 35 bar and 200 °C over NiH- and H-forms of ZSM-5 and beta zeolite catalysts which had similar Si/Al and Ni content, but different textural properties. Among the H-zeolites, H-ZSM-5 and H-beta composed of nanometer scale (ca. 10 nm) sheet-like crystals, as well as intercrystalline mesoporosity (ca. 5 nm), were found to be much more efficient for the oligomerization of 1-hexene to liquid fuel range products higher than C10 (C10 + ). In the oligomerization of ethene, identically prepared ZSM-5 and beta zeolites but with further exchange with Ni ion, also showed higher activity with remarkable C10+ product selectivity (>80%) after a single stage oligomerization, as compared to the corresponding cation form of ZSM-5 and beta zeolites without nanocrystalline and mesoporous morphology (conversion < 50% and C10+ selectivity < 30%). These results demonstrate that both small crystal size and the mesoporosity of the zeolite catalyst are critical factors for improving the diffusion limitation during the oligomerization of light olefins. This improvement was accompanied by a shift in major oligomeric product selectivity toward C10+ hydrocarbons.

Oligomerization of light olefins with silp catalysts

Oligomerization reaction of light olefins serves as a useful tool to convert light olefins to products with higher boiling point range that can be used as gasoline, jet fuel or diesel components after hydrogenation. In the past few years, supported ionic liquids have emerged as useful catalysts in many organic reactions. In the present study, the application of a silica-supported Bronsted acidic ionic liquid in the oligomerization of 1-butene and 1-pentene is investigated. The possibility of the conversion of a low boiling point range fraction of polypropylene cracking product to jet fuel or diesel components is also taken into account.

Thermodynamic study of hydrocarbon synthesis from carbon dioxide and hydrogen

AbstractThe thermodynamics of jet fuel range alkane synthesis from carbon dioxide and hydrogen has been investigated. The hydrocarbon synthesis process is divided into three elementary steps, including light olefins formation (C2‐C6) from hydrogenation of CO2, α‐olefins (C7‐C16) synthesis from oligomerization of light olefins, and hydrogenation of α‐olefins (C8‐C16) to straight‐chain paraffin (C8‐C16). The enthalpy changes and Gibbs free energy changes of the relevant reactions were calculated, and the equilibrium products distribution was computed based on the Gibbs free energy minimization method. The calculation results show that lower temperature (below 673.15 K), higher pressure (3 MPa), higher molar ratio of H2 to CO2 (3:1‐4:1), and introducing a small amount of N2 in the reactants are favorable for the hydrogenation of CO2; lower temperature (below 500 K), higher pressure (2‐3 MPa), addition of N2 is favorable for the oligomerization of light olefins; and lower temperature (below 700 K), higher pressure (2‐3 MPa), and addition of N2 is favorable for the hydrogenation of α‐olefins. The overall positive effect of introducing N2 results from its heat dilution of the process. © 2017 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Simulation of novel process of CO2 conversion to liquid fuels

Carbon dioxide utilization by conversion with hydrogen into liquid fuels was simulated based on the experimental data of a novel process using CHEMCAD. A detailed kinetic model of the novel iron-based spinel catalyst that included reverse water gas shift (RWGS), Fischer-Tropsch synthesis (FTS), C5+ hydrocarbons and oxygenates, oligomerization of olefins, as well as hydrogenation of light olefins (C2C4) was employed. The RWGS reaction rate was significantly inhibited by steam produced in the process because of the chemical equilibrium limitation and apparent strong adsorption. Therefore, periodical water removal is critical in the process, which required operation in several reactors in series or in a reactor with recycle. Those system configurations were examined and compared over a range of temperatures, pressures, weight hourly space velocities and carbon dioxide with hydrogen feed ratios. The other aspect of this process which has a significant impact on performance is the oligomerization of light olefins. Both reactors-in-series and single reactor with recycle improved dramatically the productivity and the selectivity to C5+.

Oligomerization of Light Olefins to Gasoline: An Advanced NMR Characterization of Liquid Products

Using multiple 1H and 13C NMR spectroscopic techniques, we have investigated the C8 cut from samples of liquid products obtained by the oligomerization of light olefins over solid phosphoric acid (SPA) and MTW zeolite. The carbon species present, CHn (n = 0–3), were identified by DEPT NMR and quantified using inverse-gated decoupled 13C NMR spectra. The olefinic protons and carbons as well as the types of olefins were quantified. 13C NMR shows that the amount of methyl carbons is similar for both catalysts but that methylene and methyne carbon distributions are different. The product obtained over MTW catalyst showed higher quantities of quaternary olefins, likely from type V tetrasubstituted olefins, compared to that over SPA catalyst. In addition, 2D NMR has also been attempted to understand the proton and carbon connectivities and confirmed the presence of type I and II olefins.

The oligomerization of high olefin containing hydrocarbon by-products to clean engine fuels

Nowadays it is an important issue in refineries to increase the gasoline/middle distillate flexibility because of the ever-changing engine fuel demands. One possible way is the oligomerization of light olefins (3–6 carbon atoms). The oligomerization of the C4-C6 olefin content of light FCC and more fractions with different composition was investigated on acidic ion exchange resin catalyst and premixed catalyst bed. The favourable application temperature of the ion exchange catalyst was 120–130 °C (P = 30 bar, LHSV = 1.0 h−1). The olefin conversion was also influenced by the composition of the feedstock. The best olefin conversion was achieved in the case of the feedstock with the highest olefin content (olefin conversion: 91.5%, C12+ ratio: 31.2%). Similar results were found with the application of premixed catalysts (B and C) in more oligomerization steps. Olefin conversion and selectivity was depended on the olefin and C12+ content of the feedstock. The total olefin conversion (related to the olefin content of the FCC naphtha feedstock) increased with each oligomerization steps, but it has to be investigated that how many steps could be economic. In the long term experiment (110 °C, 30 bar, 1.0 h−1) it was found that the conversion after 196 h decreased approx. 10% (compared with the initial value) but it was significantly lower after 60 h reaction time at 130 °C. The examined ion exchange resins - in the 100–120 °C temperature range - catalyze the oligomerization reactions for a long time, but an in-situ regeneration should be necessary.

Application Possibilities of Zeolite Catalysts in Oligomerization of Light Olefins

In recent decades, the application of more zeolite-type catalysts has been studied in oligomerization reaction. In the oligomerization process various boiling-range isoolefins can be produced which can be hydrogenated to isoparaffins. The oligomerization of olefins in the light FCC gasoline-matrix in the presence of zeolites has not yet been reported. Therefore, our objective was to select a catalytic system that is suitable for producing isoolefin mixtures from the referred feedstock. The activity of the studied catalytic systems was similar, but with the use of the two layered bed the share of oligomers in middle distillate boiling point range was doubled. In the favourable reaction conditions (two layered bed, T: 270 °C, P: 40 bar, LHSV: 1.0 h-1) such isoolefin mixtures can be produced from which after hydrogenation excellent, environmentally friendly gasoline, JET, and diesel gas oil blending components can be obtained.

Improved THETA-1 for Light Olefins Oligomerization to Diesel: Influence of Textural and Acidic Properties

The increase in diesel demand, especially in Europe, and the need for high fuel quality requirements are forcing refiners to move into additional processes for production of high cetane diesel in order to meet the present market trends. Oligomerization of light olefins into middle distillate range products is a viable option. The fuel produced through this technology is environmentally friendly, free of sulfur and aromatics, and the adequate choice of the heterogeneous catalyst will direct the selectivity towards low branched oligomers, which will result in a high quality product. In this work we show the benefits of combining basic desilication treatments for generation of additional mesoporosity in mono-directional Theta-1 zeolite, with selective acid dealumination steps that restore not only the microporosity to values close to those of the parent samples, but also the total and strong Brønsted acidity. These modified Theta-1 zeolites present an outstanding catalytic behavior for oligomerization of propene, with a largely increased initial activity, a much higher resistance to deactivation with time on stream, and an improved selectivity to products in the diesel fraction, as compared to the original microporous Theta-1.

Inter-conversion of light olefins on ZSM-5 in catalytic naphtha cracking condition

The inter-conversion of light olefins over four types of HZSM-5 based catalysts under cracking conditions was investigated systematically and various methods including XRD, Ar adsorption–desorption, NH3-TPD, 27Al and 31P MAS–NMR were used to characterize the effects of P modification and steaming on ZSM-5. Regardless the types of catalyst, the same behaviors of light olefin inter-conversion were observed only depending on conversion of light olefins. Also, the conversion and selectivity were not influenced by the presence of hydrogen, suggesting that light paraffins were mainly produced from hydrogen transfer during cracking rather than hydrogenation of light olefins. It can be suggested that the inter-conversion of light olefins occurs through oligomerization of light olefins and then re-cracking of the oligomerized products. To guarantee high light olefin yield in catalytic naphtha cracking, it is strongly required to suppress oligomerization of light olefins during catalytic cracking.

Directional synthesis of liquid higher olefins through catalytic transformation of bio‐oil

AbstractBACKGROUNDCatalytic transformation of bio‐oil into higher olefins can provide valuable bio‐fuels and chemicals used in the manufacture of high‐octane gasoline, detergents, plasticizers and other petrochemicals. This work explores the production of higher olefins from bio‐oil through catalytic cracking of bio‐oil along with light olefins oligomerization.RESULTSFor bio‐oil catalytic cracking, the olefins yield reached 43.8 C‐mol% with near‐complete bio‐oil conversion. The oxygenated organic compounds in bio‐oil go through deoxygenation, cracking and hydrogen transfer reactions and form light olefins over the zeolite acid sites. For the oligomerization of light olefins, the highest selectivity and yield of C5+ olefins over the LTGO catalyst reached 85.4 C‐mol% and 326.7 g kg−1cata h−1, respectively. Main products below 300°C were C6=—C12= olefins, originating from light olefin oligomerization. The influences of the reaction conditions were investigated in detail, and the reaction mechanism was addressed.CONCLUSIONBio‐oil can be catalytically converted to C2=–C4= light olefins over HZSM‐5, and further selectively transformed to C5+ high olefins via the oligomerization of light olefins over LTGO. The transformation of bio‐oil to higher olefins may be useful for the production of bio‐fuels and high value chemicals using renewable biomass. © 2013 Society of Chemical Industry

Investigation of Production of Motor Fuel Components on Heterogeneous Catalyst with Oligomerization

The production of high isoparaffin containing motor fuels which comply with the changing needs and standards is a significant research area. Because of this type of hydrocarbons have numerous application, environmental and economical benefits. One of the possible productions for this type of hydrocarbons is oligomerization of light olefins followed by their hydrogenation. Based on our experimental results we established that the examined various catalytic systems containing acidic ion exchange resin catalyst are suitable for the flexible production of different motor fuel blending components (gasoline, middle distillate) with high conversion (92.4 %) and good selectivity in particular at the process parameters (T: 130 °C, P: 30 bar, LHSV: 1.0 h−1) we found favourable.

Oligomerization of olefins from Light Cracking Naphtha over zeolite-based catalyst for the production of high quality diesel fuel

The oligomerization of light olefins to produce gasoline and middle distillates has been widely studied in the past, however in the last years the interest towards this technology has decreased and not many applications have been implemented recently. The present market trends concerning the demand of diesel to gasoline ratio, especially in Europe, are setting new opportunities for the development of an oligomerization process that can effectively convert light olefins produced by Fluid Catalytic Cracking Unit (FCCU) to high quality middle distillate fractions, increasing the global availability of Diesel fuel. This paper describes an experimental work carried out on a refinery feedstock and focused to obtain useful data for the development process. Particularly, the optimization of the Weight Hourly Space Velocity (WHSV) of the liquid feed has been studied, in order to target best matching between catalyst productivity and products quality. A ZSM-5-based catalyst has been used for the experimental study. The results showed that the observed different deactivation rate as a function of space velocity is only apparent; a unique relationship is obtained when the amount of feed processed is considered.