Isobutene Alkylation Research Articles

Cold‐model investigation of the effect of dispersed phase inlet on the dispersion uniformity in a liquid‐liquid cyclone reactor for ionic liquid‐catalyzed isobutene alkylation

AbstractA liquid‐liquid cyclone reactor was proposed for ionic liquid‐catalyzed isobutane alkylation to improve the mixing efficiency and accelerate the separation between alkylate and ionic liquid. The Eulerian‐Eulerian multiphase flow model and Reynolds stress model (RSM) were used to simulate the flow field in the reactor. A parameter, named the dispersion uniformity of dispersed phase, β, was used to quantify the dispersibility of the dispersed phase in the reaction chamber of the reactor. Moreover, the effects of the structural parameters of the dispersed phase inlet (slot) on the dispersion uniformity of the dispersed phase were investigated. As can be seen from the results, the angle of the slot has an effect on the inlet velocity direction, while the other structural parameters have an effect on the inlet velocity magnitude. The shear force is the impetus for the dispersion of the dispersed phase into the continuous phase, and the relative velocity is the cause of the shear force. Therefore, by analyzing the effect of the structural parameters of the slot on the dispersion uniformity, it can be deduced that the dispersion of the dispersed phase performs well under a suitable inlet velocity ratio range of the continuous phase to the dispersed phase (2.5‐3.5).

Effect of light phase inlet structure on liquid-liquid cyclone reactor for isobutane alkylation catalyzed by ionic liquid

The liquid-liquid cyclone reactor (LLCR) is a new and promising device suitable for the fast reaction and separation for the liquid-liquid system, such as isobutene alkylation catalyzed by acidic ionic liquids. The effect of the number and the width of light phase inlet structures of LLCR on the mixing and separation performance was investigated. The Euler-Euler model and Reynolds Stress Model were used as the multiphase model and the turbulence model, respectively. The mean local turbulence dissipation rate, mean residence time and separation efficiency of Type O (dual-inlet), Type A (tetra-inlet with half width) and Type B (dual-inlet with half width) were obtained to compare the mixing and separation performance. The results showed that both the mixing performance and the separation performance improved with the increasing number of light phase inlet. The width reduction of light phase inlet could result in the decrease of the droplet breakup, the increase the mass of transfer time and the separation efficiency.

Alkylation of isobutane and isobutene catalyzed by trifluoromethanesulfonic acid-taurine deep eutectic solvents in polyethylene glycol.

Conventional acidic catalysts for isobutane and isobutene alkylation exhibit low alkylate selectivity. Herein, we employed an acidic deep eutectic solvent, consisting of trifluoromethanesulfonic acid and taurine, in polyethylene glycol as the catalyst. Its high conversion rate and selectivity, as well as recyclability, make it suitable for alkylate gasoline preparation.

Phase holdup distribution and dispersion performance in a novel liquid–liquid cyclone reactor of isobutane alkylation catalyzed by ionic liquid

To improve the existing problems of traditional reactors for isobutane alkylation catalyzed by ionic liquid，a novel liquid–liquid cyclone reactor (LLCR) was designed for the liquid–liquid heterogeneous reaction. The LLCR mainly includes two parts: a reaction chamber and a separation chamber, so the isobutene alkylation reaction and separation between the products and catalyst could occur in the same reactor. Compared with the traditional hydrocyclone, the LLCR consists of two kinds of inlets, one for the light phase and one for the heavy phase. The light phase is injected into the reactor through two symmetric tangential slots in the inlet, while the heavy phase inlet is an axial entry with a guided vane. The phase holdup distribution and dispersion uniformity of light phase in the LLCR were investigated using a novel sampling device and software MATLAB R2012b. One special radius was proposed, rs, which separated the reaction chamber into two parts: upward flow and mixing area. Experimental results indicate that when the total inlet flow is 2m3/h, the flow field in the LLCR is irregular. Moreover, the discharge of the upward flow timely benefits the stability of flow field in the LLCR. Besides, a new parameter, dispersion uniformity of the light phase, β, was used to evaluate the dispersion performance of the light phase in LLCR. By analyzing the dispersion uniformity under different operational parameters, the dispersion of the light phase becomes more desirable under high total inlet flow, feed ratio and overflow ratio.

Thermodynamic Analysis of the Formation of C8 Isomers in the Alkylation of Isobutane by Olefins

The process and results of a thermodynamic analysis of C8 isomer formation upon the alkylation of isobutene by olefins using thermobaric dependence and an information model are presented. The experimental data were used to determine the probability of reaction in the 1-3 MPa pressure range. No significant change in the Gibbs energy was found to occur at pressures above 1 MPa.

On Synthesis and Characterization of Sulfated Alumina–Zirconia Catalysts for Isobutene Alkylation

The porous structure and surface acid–base properties of sulfated zirconia, alumina and alumina–zirconia applied in isobutylene alkylation were characterized using a variety of physico-chemical methods. Catalytic activity was related to catalyst physico-chemical properties.

Synthesis of 3,3-Dimethylbutanol and 3,3-Dimethylbutanal, Important Intermediates in the Synthesis of Neotame

It has been shown that some N-alkyl derivatives of Aspartame (1) are enhanced sweetening agents [1]. In particular, the 3,3-dimethylbutyl derivative, 2, (Neotame) is about 70 times sweeter than Aspartame. With this in mind a research program directed toward the synthesis of 3,3-dimethylbutanal (3) was begun. The first phase of this research involved the synthesis of 3,3-dimethylbutanol (4) by the acid catalyzed alkylation of isobutene with ethylene to give the sulfate ester [2] which was readily hydrolyzed to the alcohol, 4, in isolated yields in the 70–75 % range. It was found that the most efficient method for the conversion of 4 to the aldehyde, 3, was by a vapor phase dehydrogenation over a copper catalyst. The effect which the reaction variables have on the production of 4 will be discussed. This will include factors such as the ethylene pressure, the acid/isobutene ratio, the use of a hydrocarbon solvent, the reaction temperature and the mode of addition of the isobutene. The discussion of the dehydrogenation procedure will include the nature of the catalyst used and the reaction parameters needed to maximize the formation of 3 and keeping the amount of the over-oxidation carboxylic acid product below 1 %.

Influence of acidity of modified chloroaluminate based ionic liquid catalysts on alkylation of iso-butene with butene-2

Abstract In the present work, aluminium chloride based ionic liquids (ILs) were used as catalysts for alkylation of iso-butane with butene-2. Some additives such as, transition metal salts, water and acidic cation exchange resins were used to improve the selectivity of the main products and the yield of reaction. A high content of the desired trimethylpentanes (TMPs) (up to 72.3%) and thus a high research octane number (RON up to 98) of the alkylate were received on using CuCl modified triethylamine hydrochloride aluminium chloride ([Et3NH]Cl/AlCl3) (molar fraction of AlCl3 is 0.6) at − 5 °C over a period of 15 min. The effectiveness of additives is assumed to explain by the formation of Bronsted acid or complexes which exhibit the Bronsted acidity or superacidity. The acidity of investigated catalytic systems was evaluated by FT-IR and confirmed that. The Bronsted and Lewis acidic sites were detected by FT-IR. The Lewis acidity can be adjusted mainly by mol fraction of AlCl3 while the Bronsted acidity can be increased by using the suitable amounts of additives. This is a valuable guide to explain the mechanism and to select the catalysts for alkylation.

To the mechanism of the isobutane alkylation with butenes

The arguments in favor of a change in the accents at the description of the reaction mechanism of the isobutene alkylation with butylenes in the presence of sulfuric acid are proposed. The reaction of sulfate sulfur reduction that until now considered as the side process is proposed to suggest as just the initiation of chain process which includes generation of tert-butyl cations. Such a concept makes it possible to explain a number of characteristic experimental data, in particular failure of attempts of creation of the effective solid catalyst for the alkylation on the basis of the sulfated zirconium oxides.

New approaches to the study of localization of carbonaceous deposits on acidic zeolites

The discrete-successive coke micro oxidation (DSCMO) method has been improved in the direction of its sensibility increase. Two acid catalysts on the base of NaX zeolite, modified by mint of SiCl4 for the purpose of deactivating the outer surface of zeolite crystals, have been synthesized. The samples were deactivated in the reaction of isobutane with isobutene alkylation. The coke formed has been investigated by the use of improved DSCMO method. It has been shown that coke of different H/C ratios burning down alternates with burning of pure carbon, and on these grounds a conclusion has been drawn about the successive burning of carbonaceous deposits on the outer surface of zeolite crystals, in the great cavities, sodalite cells, and finally in the hexagonal prisms.

1-11 ゼオライト上でのイソブタンのエチレンによるアルキレーション((4)改質,Session 1 石炭・重質油等)

1-11 ゼオライト上でのイソブタンのエチレンによるアルキレーション((4)改質,Session 1 石炭・重質油等)

Alkylation of isobutene with 2-butene using composite ionic liquid catalysts

Abstract A composite ionic liquid was used as an acid catalyst for the liquid phase alkylation of isobutane and 2-butene. The main product obtained was trimethylpentane (>85 wt.%) and the research octane numbers of the alkylates was 98–101. In the ionic liquid sample, a composite anion [AlCl4CuCl]− was detected by means of ESI-MS. This new species was also confirmed by 27Al NMR and FT-IR characterizations. The effects of anion composition on the product distribution have been investigated. The composite anion plays important roles in improving alkylate quality.

Simulation of three-phase spouted bed reactor for solid catalyst alkylation

A process simulator was developed to afford better understanding of the performance of the isobutane–butene alkylation plant that uses a three-phase spouted bed-reactor hydrocyclon and a super acid solid catalyst. The system was simulated by using correlations developed in the cold model and apparent kinetic constants measured in a batch reactor for 1-butene–isobutene alkylation. A new type of catalyst, PtSO 4Zr/TiO 2, was used in the presence of recycled alkylate and hydrogen. The computer simulator numerically solved the mass and energy balance equations for the riser and downcomer. It was determined that a gas–liquid–solid with similar properties to the system under study do not shown a charm regime of flow and that the new design of the gas disengaging zone at the end of the riser prevent the undesired recirculation of large bubble and provide stability. New gas hold-up, linear velocity of the liquid, recycle ratio, and mass transfer correlations obtained reproduce the result within a ±10% error. The result of the alkylation plant simulation indicated a large influence of linear velocity and temperature on activity, selectivity, and stability of catalytic system. The other important operating parameters are alkylate/olefin and isobutane/olefin ratios. The optimal operating conditions were determined for a particular catalyst and set of cost.

Sulfuric Acid Alkylation of Isobutane with Butylenes in a Continuous–Flow Tubular Contactor

The results of pilot–industrial tests of sulfuric acid alkylation of isobutene from butane–butylene fractions in a tubular continuous–flow contactor operating in the turbulent regime with internal cooling are reported. After the time of contact (≈30 sec) of the reagents, an alkylate that satisfies the requirements for specifications is formed. Data from the chromatographic–mass spectrometric analysis of the alkylate are reported.

Synthesis of isoprene from isobutene and methanol over supported silver catalysts.

One-step synthesis of isoprene from isobutene and methanol over suppsoilrvterd catalysts was investigated. Among the various metal oxides, SiO2 was found to be most suitable as catalyst carrier.Highly dispersed Ag on SiO2 produced acid sites of H0>-3.0 at which isoprene was thought to be formed by condensation of isobutene with the formaldehyde produced from methanol by the action of the Ag component. Only a small amount of isoprene was obtained at 280°C in the absence of oxygen; however, at higher temperatures, a considerable amount of isoprene was obtained even in the absence of oxygen, while isopentenes were co-produced probably by alkylation of isobutene with methanol and by hydrogenation of isoprene.

Effectiveness of various catalysts in alkylating phenol with isobutene

1. A number of catalysts have been investigated in the phenol—isobutene alkylation reaction under comparable conditions, these catalysts including BF3, H3PO4· BF3, AlCl3, H2SO4, and AlCl2 · HSO4; it was shown that boron fluoride, taken in 0.8–1% quantity, is the most active catalyst and gives the highest yield of p-tert-butylphenol. 2. An investigation has been made of the effect of various factors on alkylate yield and composition in phenol isobutene alkylation with boron fluoride. The yield of p-tert-butylphenol reaches 78–88% of the theoretical.