Stirred Tank Batch Research Articles

Improvement of synthetic activity and stability of a commercial lipase in a low-water system via immobilization of hydrated lipase aggregates

Abstract Activation and immobilization of a commercial lipase from Candida cylindracea were investigated to improve its catalytic performance for esterification reaction between 1-octanol and three butyric acid derivatives in low-water solvent-free systems. Lipase powder was suspended in 1-octanol, which is the alcohol substrate of the esterification reaction, and then an appropriate amount of water (10% to 1-octanol in volume) was added to form hydrated lipase aggregates. Lipase exhibited high activity in this aggregated state, in contrast with the very low activity of nonhydrated lipase powder. We believe that activation using this hydration-aggregation pretreatment was based on interfacial activation at the 1-octanol-water interface. The hydrated lipase aggregates had paste-like morphology and could be immobilized on nonwoven fabrics by physical compression. Polypropylene exhibited the best specific activity among the tested nonwoven fabric materials. A stirred tank batch bioreactor was developed using lipase-immobilizing polypropylene nonwoven fabric sheets. This bioreactor stably maintained its reaction performance in repetitive-batch (maximum 30 times, for a total of 2000 h) esterification with three different acid substrates. The ester yields were over 90% throughout the all repetitive batches. During repeated reaction, the immobilized lipase maintained its water content at a constant level, thus exhibiting catalytic activity in nonaqueous reaction systems.

Kinetic modeling of the simultaneous etherification of ethanol with C4 and C5 olefins over Amberlyst™ 35 using model averaging

A kinetic study on the simultaneous liquid-phase etherification of ethanol with isobutene (IB), 2-methyl-1-butene (2M1B) and 2-methyl-2-butene (2M2B) catalyzed by Amberlyst™ 35 to form ethyl tert-butyl ether (ETBE) and tert-amyl ethyl ether (TAEE) is presented. Isothermal experimental runs were carried out in a stirred tank batch reactor in the temperature range 323–353K at 2.0MPa, starting from different initial concentrations. Obtained reaction rates were free of catalyst load, internal, and external mass transfer effects. Mathematical fitting of a series of systematically originated models, model selection, and model averaging procedures were applied to find the best model and to draw conclusions about the reaction mechanism. The selected model involves a saturated catalytic surface with the participation of two active sites in etherification reactions and one active site in isoamylenes isomerization. Apparent activation energies for ETBE formation from IB and EtOH, TAEE formation from 2M1B and EtOH, TAEE formation from 2M2B and EtOH, and double bond isomerization between 2M1B and 2M2B were 72.8±1.4, 74.9±2.8, 81.2±2.2 and, 76.5±7.2kJ/mol, respectively. The alkenes with the double bond in terminal position were more reactive towards EtOH than 2M2B, with the double bond in internal position.

Solvent-free semihydrogenation of acetylene alcohols in a capillary reactor coated with a Pd–Bi/TiO2 catalyst

A solvent-free semihydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol was performed in a capillary reactor (10m long, 0.53mm i.d.) coated with a titania supported Pd–Bi catalyst. Several coatings with different Pd/Bi ratio have been prepared. The catalysts have been characterized with SEM, TEM, EDX, XRD analysis and N2 adsorption–desorption measurements. The maximum alkene yield of 90% was obtained at a molar Pd/Bi ratio of 11. The yield was increased to 95% in the presence of 10mol.% pyridine in the reaction mixture. The alkene selectivity decreased with time due to leaching of Bi. The leaching was fully suppressed in the presence of 1vol.% acetic acid in the reaction mixture. The catalyst remained stable for 100h of continuous operation. The results demonstrate that capillary reactors provide alkene selectivity the same compared to ideal stirred tank batch reactors.

Equilibrium conversion, selectivity and yield optimization of the simultaneous liquid-phase etherification of isobutene and isoamylenes with ethanol over Amberlyst™ 35

A prospective study on the product distribution at chemical equilibrium for the simultaneous liquid-phase etherification of isobutene and isoamylenes with ethanol over Amberlyst™ 35 is presented. Experiments were performed isothermally in a 200cm3 stirred tank batch reactor operating at 2.0MPa. Initial molar ratios of alcohol/olefins and isobutene/isoamylenes ranged both from 0.5 to 2, and temperature from 323 to 353K. Reactants equilibrium conversion, selectivities and yields toward products were clearly affected by the experimental conditions. Experimental etherification yields have been modeled using the response surface methodology (RSM), combined with the stepwise regression method to include only the statistically significant variables into the model. The multiobjective optimization (MOO) of etherification yields has been carried out numerically, by means of the desirability function approach, and graphically, by using the overlaid contour plots (OCP). Optimal conditions for the simultaneous production of ethyl tert-butyl ether (ETBE) and tert-amyl ethyl ether (TAEE) have been found to be at low temperatures (323 to 337K) and initial molar ratio alcohol/olefins close to 0.9 and isobutene/isoamylenes close to 0.5.

모델 콜타르 유분 중에 함유된 질소고리화합물의 추출에 관한 메탄올과 포름아마이드의 비교

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction was compared by the methanol and formamide extraction. The model coal tar fraction comprising four kinds of NHC (NHCs : quinoline, iso-quinoline, indole, quinaldine) and three kinds of bicyclic aromatic compound (BACs : 1-methylnaphthalene, 2-methylnaphthalene, dimethylnaphthalene), biphenyl and phenyl ether was used as a raw material. The aqueous solution of methanol and formamide were used as solvents. A batch-stirred tank was used as the raw material - a solvent contact unit of this work. Independent of the solvent used, the distribution coefficient of NHCs sharply increased by decreasing the initial volume ratio of water to the solvent and increasing the equilibrium operation temperature, whereas, the selectivity of NHCs in reference to BACs decreased. Decreasing the initial volume ratio of solvent to feed resulted in deteriorating distribution coefficients, but the selectivity of NHCs in reference to BAC was almost the constant. The distribution coefficient of NHCs by the methanol extraction was 3∼5 times higher than that of NHCs by the formamide extraction, inversely, the selectivity of NHCs based on BACs by the formamide extraction was 3∼7 times higher than that of NHCs by the methanol extraction. Furthermore, two different solvent extraction methods by adding the extraction processing speed to the balance between solvency and selectivity of NHCs were compared.

Studies on the effect of coal particle size on biodepyritization of high sulfur coal in batch bioreactor

Abstract The moderate thermophilic mix culture bacteria were used to depyritize the Illinois coal of varying particle sizes (-100 μm, 100-200 μm, +200 μm). Mineral libration analysis showed the presence of pyrite along with other minerals in coal. Microbial depyritization of coal was carried out in stirred tank batch reactors in presence of an iron-free 9K medium. The results indicate that microbial depyritization of coal using moderate thermophiles is an efficient process. Moreover, particle size of coal is an important parameter which affects the efficiency of microbial depyritization process. At the end of the experiment, a maximum of 75% pyrite and 66% of pyritic sulphur were removed from the median particle size. The XRD analysis showed the absence of pyrite mineral in the treated coal sample. A good mass balance was also obtained with net loss of mass ranging from 5-9% showing the feasibility of the process for large scale applications.

Pharmaceutical crystallisation processes from batch to continuous operation using MSMPR stages: Modelling, design, and control

In pharmaceuticals manufacturing, the conversion of conventional batch crystallisations to continuous mode has the potential for intensified, compact operation and more consistent production via quality-by-design. A pragmatic conversion approach is to utilise existing stirred tank batch crystallisers as continuous mixed-suspension mixed-product removal (MSMPR) stages. In this study, a rigorous and general mathematical model is developed for a pharmaceutical crystallisation process under continuous MSMPR operation. In the proposed changeover from batch to continuous operation, concentration control (C-control), which has been well accepted in batch crystallisation operation, is further extended to facilitate the convenient design of the steady-state operating point of a continuous MSMPR crystalliser; an objective is to ensure that the start-up procedures and on-line control conditions fall within the design-space of the original batch operation. Both single-stage and cascaded two-stage MSMPR crystallisers were investigated and compared to the conventional batch operation. It was observed that despite the production of a smaller number-based mean crystal size, the proposed continuous MSMPR operation achieved higher production capacity with shorter mean residence time and comparable product yield to the batch operation. Lastly, the robustness of C-control strategy against uncertainties in crystallisation kinetics was also demonstrated for the proposed continuous MSMPR operation.

Fermentative production of dextran using Leuconostoc spp. isolated from fermented food products

Leuconostoc spp. (LS1and LI1) isolated from sauerkraut and idli batter was selected for dextran production. To enhance the yield of dextran, effects of various parameters such as sucrose concentration, pH, temperature, incubation and inoculum percentage were analyzed. The optimum sucrose concentration for the Leuconostoc spp. (LS1 and LI1) was found to be 15% and 25% respectively. Isolates produced maximum dextran after 20 h of incubation at 29° C and the optimum pH was found between 8 and 8.5. The inoculum concentration of 7.5% was more favorable for the production of dextran by Leuconostoc spp. (LS1 and LI1). The growth kinetic parameters were studied and compared for the strains LS1 and LI1. Mass production of dextran was carried out using a stirred tank batch reactor. FTIR analysis was done to determine the functional groups of dextran. sephadex is prepared by cross linking dextran using epichlorohydrin and the functional groups are determined by FTIR analysis.

9성분계 모델 콜타르 흡수유 중에 함유된 질소고리화합물의 메탄올 추출

9성분계 모델 콜타르 유분 중에 함유된 질소고리화합물(NHC)의 분리를 분배평형에 의해 검토했다. 원료로서는 NHC group (NHCs; quinoline (Q), iso-quinoline (iQ), indole (In), quinaldine(Qu)), 2환 방향족 화합물 group (BACs; 1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp)과 phenyl ether (Pe)로 제조한 모델 콜타르 유분을, 용매로서는 메탄올 수용액을 각각 사용했다. 액-액 접촉 장치로서는 회분 교반기를 각각 사용했다. 평형조작 온도가 상승함에 따라 NHCs의 분배계수는 증가했으나, 역으로 BACs를 기준한 NHCs의 선택도는 감소했다. 초기 물/용매의 체적비가 감소함에 따라 BACs를 기준한 NHCs의 선택도는 급격히 감소했으나, NHCs의 분배계수는 증가했다. 일정 조건하에서, 각 group별 분배계수와 BACs를 선택도의 순서는 NHCs > Bp > BACs > Pe와 NHCs > Bp > Pe를 각각 나타냈다. 또한 전체 성분에 대한 분배계수의 순서는 In > iQ = Q > Qu > Bp > 1MN = 2MN > Pe > DMN을 나타냈다. 메탄올 추출에 의해 얻어진 NHCs의 최대 수율과 BACs를 기준한 NHCs의 최대 선택도는 각각 94%, 23이었다. 본 연구를 통해 얻어진 실험적 결과를 이용하여 콜타르 중에 함유된 NHCs의 회수공정을 검토했다. The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction of nine components system was investigated by distribution equilibrium. The model coal tar fraction comprising NHC group (NHCs; indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine(Qu)), bicyclic aromatic compound group (BACs; 1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp) and phenyl ether (Pe) and the aqueous methanol were used as the raw materials and the solvent of this work, respectively. A batch-stirred tank was used as the liquid-liquid contact unit of this work. The distribution coefficient of NHCs increased by increasing the equilibrium operation temperature, whereas the selectivity of NHCs with respect to BACs decreased. Decreasing the initial volume ratio of water to the solvent resulted in deteriorating the selectivity of NHCs in reference to BACs, but improving the distribution coefficients of NHCs. At a fixed experimental condition, the sequence of the distribution coefficient and the selectivity with reference to BACs for each groups was increased in order of NHCs > Bp > BACs > Pe and NHCs > Bp> Pe, respectively. Also, the sequence of the distribution coefficient for entire compounds was in order of In > iQ = Q > Qu > Bp > 1MN = 2MN > Pe > DMN. The maximum yield of NHCs and the selectivity of NHCs based on BACs obtained by methanol extraction were 94 and 23%, respectively. Furthermore, the recovery process for NHCs from coal tar was studied by using the experimental results from this work.

Study of a multi-phase hybrid heat exchanger-reactor (HEX reactor): Part I – Experimental characterization

This study focuses on gaining fundamental insights into the sparsely explored area of reacting multiphase flows in a compact heat exchanger. Chevron plate heat exchangers have been demonstrated to possess superior thermal performance, scalability, and mixing capability compared to more traditional shell-in-tube heat exchangers or stirred tank batch reactors. This study explores the hydrodynamic behavior of gas-evolving reacting flows in chevron plate heat exchangers. Experimental characterization of a plate heat exchanger/chemical reactor (in multi-phase flow configuration) utilizing high-speed video and axial pressure measurements was conducted. Existing correlations that were developed using air–water flow in PHEs predicted with acceptable accuracy the total pressure drop in the HEX reactor.

Precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor operated in batch at constant power density

A meso oscillatory flow reactor (meso‐OFR) was successfully applied for the precipitation of hydroxyapatite (HAp) nanoparticles. Mixing efficiency of the mesoreactor operated batchwise in a vertical tube was evaluated at constant power density, by monitoring variation of hue values upon mixing both spatially and temporally. The best operating conditions for fast mixing and a more homogeneous reaction medium were verified for f = 0.83 Hz and x0 = 4.5 mm. HAp precipitation was then carried out under these conditions at 37 °C for different mixing Ca/P molar ratios. HAp nanoparticles with a mean size (d50) of about 67 nm and a narrow size distribution were obtained. Furthermore, the obtained results show the advantages of the meso‐OFR over a stirred tank batch reactor due to the production, about four times faster, of smaller and more uniform HAp nanoparticles. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4483–4493, 2013

Palm-based medium-and-long-chain triacylglycerol (P-MLCT): production via enzymatic interesterification and optimization using response surface methodology (RSM).

Structured lipid such as medium-and long-chain triacylglycerol (MLCT) is claimed to be able to suppress body fat accumulation and be used to manage obesity. Response surface methodology (RSM) with four factors and three levels (+1,0,-1) faced centered composite design (FCCD) was employed for optimization of the enzymatic interesterification conditions of palm-based MLCT (P-MLCT) production. The effect of the four variables namely: substrate ratio palm kernel oil: palm oil, PKO:PO (40:60-100:0 w/w), temperature (50-70°C), reaction time (0.5-7.5h) and enzyme load (5-15% w/w) on the P-MLCT yield (%) and by products (%) produced were investigated. The responses were determined via acylglycerol composition obtained from high performance liquid chromatography. Well-fitted models were successfully established for both responses: P-MLCT yield (R (2) = 0.9979) and by-products (R (2) = 0.9892). The P-MLCT yield was significantly (P < 0.05) affected by substrate ratio, reaction time and reaction temperature but not enzyme load (P > 0.05). Substrate ratio PKO: PO (100:0 w/w) gave the highest yield of P-MLCT (61%). Nonetheless, substrate ratio of PKO: PO (90:10w/w) was chosen to improve the fatty acid composition of the P-MLCT. The optimized conditions for substrate ratio PKO: PO (90:10 w/w) was 7.26h, 50°C and 5% (w/w) Lipozyme TLIM lipase, which managed to give 60% yields of P-MLCT. Up scaled results in stirred tank batch reactor gave similar yields as lab scale. A 20% increase in P-MLCT yield was obtained via RSM. The effect of enzymatic interesterification on the physicochemical properties of PKO:PO (90:10 w/w) were also studied. Thermoprofile showed that the P-MLCT oil melted below body temperature of 37°C.

Process intensification and optimization for hydroxyapatite nanoparticles production

Precipitation processes are widely used in industry for the production of particulate solids. Efficient mixing of the reagents is of major importance for the chemical and physical nature of the synthesized particles. Recently, microreactors have been studied to overcome homogeneity problems found when using stirred tank batch reactors. The present work investigated an ultrasonic tubular microreactor for the continuous-flow precipitation of hydroxyapatite (HAp), both in single-phase flow (SPF) and in gas–liquid flow (GLF). HAp nanoparticles were yielded for both configurations under near-physiological conditions of pH and temperature. The as-prepared particles, especially those that were prepared under GLF, show improved characteristics compared to commercial powder or powder obtained in a stirred tank batch reactor. Primary particles are smaller, particle shape is more homogeneous, and the aggregation degree of the particles is lower.

Continuous-flow precipitation of hydroxyapatite in ultrasonic microsystems

This paper describes the continuous-flow precipitation of hydroxyapatite Ca5(PO4)3OH (HAp) in two ultrasonic microreactors using diluted aqueous solutions of calcium and phosphate at 37°C. Precipitation of HAp was first carried out in a tubular microreactor immersed in an ultrasonic bath, where single-phase (laminar) flow and segmented gas–liquid flow were both evaluated. The single-phase flow study was then conducted in a novel microfluidic device developed at MIT. It consists of a Teflon stack microreactor with an integrated piezoelectric element (Teflon microreactor), thereby allowing the direct transmission of ultrasound to the reactor. Both microsystems produce single-phased calcium-deficient carbonated HAp under near-physiological conditions of temperature and pH. In addition, particle aggregation and primary particle size were significantly reduced in the segmented-flow tubular microreactor and in the Teflon microreactor. The as-prepared particles mostly consisted of rod-like shape nanoparticles with dimensions below 100nm in length and around 20nm in width. Further, the microreactors used yielded HAp particles with improved characteristics, namely higher crystallinity and less carbonate contamination, when compared to the HAp particles produced in a stirred tank batch reactor.

Kinetics Study for Ion-Exchange-Resin Catalyzed Hydrolysis of Methyl Glycolate

The hydrolysis of methyl glycolate catalyzed by commercial cation-exchange resin was studied in a stirred tank batch reactor. It was found that 001×7 resin was an effective catalyst for the hydrolysis of methyl glycolate. The effects of catalyst loading, initial reactant ratio and temperature have been examined in detail. The kinetics of glycolate hydrolysis was evaluated by the use of the pseudohomogeneous model, which was found to represent the kinetics fairly well, due to the total dissociation of the active sulfonic acid group in swollen polymer resin in the presence of water. The kinetics was expressed in terms of activities and the activity coefficients were estimated by using the group contribution method UNIFAC. The activation energy was found to be 59.26 kJ/mol for 001×7 resin, indicating surface reaction is the rate-controlling step.

Highly efficient removal of Cu(II), Zn(II), Ni(II) and Fe(II) from electroplating wastewater using sulphide from sulphidogenic bioreactor effluent

A bench-scale, stirred-tank batch precipitator was used to assess the selective removal of Cu2+, Zn2+, Ni2+ and Fe2+ from acidic electroplating wastewater using sulphide from a sulphidogenic bioreactor effluent. At pH ≈ 1.7,>99% of Cu was selectively precipitated, over Zn, Ni and Fe, from the wastewater as pure CuS by recycling H2S from the bioreactor effluent via N2 sparging, resulting in a Cu effluent concentration<0.4 mg/L. The rate of Cu precipitation increased from 1.6 to 6.4 mg Cu/(L·min) when the pH of the bioreactor effluent decreased from 7.5 to 5.5. Experiments focusing on the precipitation of Zn, Ni and Fe from the wastewater devoid of Cu (at pH ≈ 1.7), using sulphide-rich bioreactor effluent, achieved ∼85–97% precipitation efficiency for Zn, ∼25–92% for Ni, and ∼2–99% for Fe, depending on the initial sulphide/metal molar ratio. The sulphide/metal ratio of 1.76 was found to be optimal for the precipitation of Zn, Ni and Fe with sulphides and, to a lesser extent, with hydroxides, resulting in residual metal concentrations of 1 mg Zn/L, 3 mg Ni/L, and 0.5 mg Fe/L. These findings suggest the potential of waste biogenic sulphides for the selective recovery of valuable metals from acidic metal-rich industrial wastewaters.

Submerged Fermentation of the Edible Mushroom Pleurotus ostreatus in a Batch Stirred Tank Bioreactor as a Promising Alternative for the Effective Production of Bioactive Metabolites

The aim of this study was to investigate the potential of the submerged fermentation procedure in the production of bioactive metabolites of the common edible mushroom Pleurotus ostreatus. The biomass of the mushroom strain was produced by submerged fermentation in a batch stirred tank bioreactor and extracted by solvents of increasing polarity. The dichloromethane and methanol extract were fractioned by different techniques including Adsorption Chromatography and Fast Centrifugal Partition Chromatography (FCPC). The structures of pure compounds were elucidated with 1D/2D NMR-spectroscopic analyses, and chemical correlations combined with GC/MS and LC/MS experiments. Nineteen metabolites (e.g., fatty acids, phenolic metabolites, nucleotides and alkaloids) were isolated. Beyond the production of known metabolites, we report herein the production also of trans-3,4-dihydro-3,4,8-trihydroxynapthalen-1(2H)-one, indolo-3-carboxylic acid, 3-formylpyrrole and 4-hydroxybenzoic acid, that have pharmaceutical interest and are isolated for the first time from Pleurotus strains.This work indicates the great potential of the established bioprocess for the production of P. ostreatus mycelia with enhanced metabolic profile.

Liquid Membrane Permeation of Nitrogen Heterocyclic Compounds Contained in Model Coal Tar Fraction

We investigated the separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp) and phenyl ether (Pe) by liquid membrane permeation (LMP). A batch-stirred tank was used as the permeation unit. An aqueous solution of saponin and n-hexane were used as the liquid membrane and the outer oil phase, respectively. Yield and selectivity of individual NHC was much larger than that of BAC, Bp and Pe. Increasing the initial mass fraction of the saponin to the membrane solution () and the initial volume fraction of O/W emulsion to total liquid in a stirred tank () resulted in deteriorating the yield of individual NHC, but increasing the stirring speed (N) resulted in improving the yield of each NHC. With increasing , the selectivity of each NHC based on DMNs increased. Increasing and N resulted in decreasing the selectivity of individual NHC based on DMNs. At an experimental condition fixed, the sequence of the yield and selectivity in reference to DMNs for each NHC was Q > Qu = iQ > In. Furthermore, we compared LPM method with methanol extraction method in view of the separation efficiency (yield, selectivity) of NHC.

Comparative Study of Sterol Ester Synthesis using Thermomyces Lanuginosus Lipase in Stirred Tank and Packed‐Bed Bioreactors

AbstractA comparative study was done on the production of different sterol esters using a stirred tank batch reactor (STBR) and packed bed reactor (PBR) using Thermomyces lanuginosus (Lipozyme TLIM) enzyme, a commercially immobilized lipase. Different oils were used as the sources of particular fatty acids, e.g., fish oil for n‐3 polyunsaturated fatty acids (n‐3 PUFA), linseed oil for alpha linolenic acid (ALnA) and mustard oil for erucic acid. Reaction parameters, such as substrate molar ratio, reaction temperature and enzyme concentration, were standardized in the STBR and maintained in the PBR. To provide equal time of residence between the substrate and enzyme in both the reactors for the same amount of substrates, the substrate flow rate in the PBR was maintained at 0.27 ml/min. Thin layer chromatography was used to monitor the reaction, and column chromatography was used to determine the product yields. Fatty acid compositions of the esters were determined by gas chromatography. The study showed that the packed bed bioreactor was more efficient than the batch reactor in sterol‐ester synthesis with less migration of acyl groups.

Isoamylene Trimerization in Liquid-Phase over Ion Exchange Resins and Zeolites

Liquid-phase trimerization of 2-methyl-1-butene and 2-methyl-2-butene mixtures over solid acid catalysts was carried out in a batch-stirred tank reactor in the temperature range 333−373 K. Diisoamylenes and triisoamylenes were the main products. Cracking products among C6−C9 and C11−C14 were also obtained under the assayed conditions. The catalityc performance of five different acidic ion exchange resins (Amberlyst 15, Amberlyst 35, Amberlyst 70, Purolite CT-252, Purolite CT-276) and four zeolites (H-BEA-25, H-FAU-30, H-FAU-6 and H-MOR-20) was assessed. Experimental results showed that Amberlyst 15 and H-FAU-30 were the best catalysts for isoamylene trimerization, with selectivities above 40% at 373 K. The most influencing physical properties of the catalysts on the selectivity toward dimers and trimers were acid capacity, acid strength, and specific surface area for resins, and microporous surface area for zeolites. Isoamylene trimerization extent was larger at higher temperature. The most probable mecha...