Two-phase Reaction System Research Articles

Water-Doped Brønsted Acidic Protic Ionic Liquids for Enhanced Tributyl Citrate Synthesis in a Two-Phase Esterification System.

Tributyl citrate (TBC) plays a crucial role as a plasticizer, enhancing the flexibility of polymers such as polyvinyl chloride. Its biodegradability and non-toxic nature contribute to eco-friendly appeal, making it a preferred additive in diverse industries, including food packaging, medical devices, toys, and consumer goods. Herein, a method for the synthesis of TBC using inexpensive Brønsted acidic protic ionic liquids (ILs) in a two-phase reaction system is presented. The esterification process is carried out with high yield (>99 %), selectivity (up to 98 %) and short reaction time of 2 h. The catalyst in the form of IL shows excellent performance and stability, desirable for industrial applications.

Hydration, mechanical performance and porosity of Portland cement pastes with functionalized nanosilica with APTES

This study reports on the microstructure of Portland cement pastes with nanosilica (NS) and amino-functionalized nanosilica (NSF). For this, NSF dispersion was prepared in a two-phase reaction system, consisting of an aqueous dispersion with dichloromethane, using 3-aminopropyltriethoxysilane (APTES):NS molar ratio 1:28.62. Cement pastes were analyzed in the fresh state by consistency and in the hardness state by compressive strength, conduction calorimetry, X-ray diffraction (XRD), thermal analysis (TGA), infrared spectroscopy (FTIR) and mercury intrusion porosimetry (MIP). It was verified that the functionalized nanoparticles affected the hydration kinetic properties, indicating the extension of the induction period. Through microstructural analysis, it was observed that NSF increased the amount of the main mineralogical phases generated during Portland cement hydration or the pozzolanic reaction. Therefore, the NSF improves the Portland cement hydration and contributes to the densification of the microstructure of the cement pastes at 28 days.

Pyrene-Based Covalent Organic Frameworks for Photocatalytic Hydrogen Peroxide Production.

Four highly porous covalent organic frameworks (COFs) containing pyrene units were prepared and explored for photocatalytic H2 O2 production. The experimental studies are complemented by density functional theory calculations, proving that the pyrene unit is more active for H2 O2 production than the bipyridine and (diarylamino)benzene units reported previously. H2 O2 decomposition experiments verified that the distribution of pyrene units over a large surface area of COFs plays an important role in catalytic performance. The Py-Py-COF though contains more pyrene units than other COFs which induces a high H2 O2 decomposition due to a dense concentration of pyrene in close proximity over a limited surface area. Therefore, a two-phase reaction system (water-benzyl alcohol) was employed to inhibit H2 O2 decomposition. This is the first report on applying pyrene-based COFs in a two-phase system for photocatalytic H2 O2 generation.

Development of a two-phase flow reaction system for DNA-encoded amide coupling

Synthesis platforms are of particular interest to DNA-encoded library (DEL) technologies to facilitate chemistry development, building block validation, and high-throughput library synthesis.

The Utilization of Two-Phase Catalytic System in Enantioselective Biotransformation of Racemic Atenolol

There are several methods that allow enantiomerically pure compounds to be obtained. In the study presented herein, the enantioselective biotransformations of (R,S)-atenolol were performed with the use of various catalytic systems containing ionic liquids and toluene as a reaction medium, vinyl acetate as an acetylating agent as well as lipases from Candida rugosa. The conducted studies profs that, the use of the two-phase reaction system enables the reuse of the biocatalyst in another cycle and allows to achieve satisfactory kinetic resolution parameters.

Efficient epoxidation of styrene within pickering emulsion-based compartmentalized microreactors

The epoxidation of styrene is an important route to synthesize organic intermediate, but how to effectively promote the formation of target superoxide radicals and then regulate the production of styrene oxide in two-phase reaction system remains an urgent challenge. In this study, MnOx nanocatalysts with abundant oxygen vacancies were fabricated using reverse-micelle as template, and then were endowed with an amphiphilic surface through post-modification. With such MnOx catalysts, Pickering emulsion could be formulated, in which numerous compartmentalized droplet microreactors were created for the epoxidation of styrene. The rich oxygen defects on MnOx were found to be useful to improve the chemisorption of t-butylhydroperoxide, and the active complexes formed by coordination of Mn3+ with N, N-dimethylformamide favored the generation of preferable superoxide radicals for the synthesis of styrene oxide. Moreover, it was also found that compartmentalization effects arising from Pickering emulsion droplets modifies the radicals reaction path, significantly improving the catalytic efficiency and selectivity. As a result, in the Pickering emulsion system, 90.0% selectivity towards styrene oxide and a turnover frequency of 581 h−1 could be obtained, which were higher than ever reported results. The Pickering emulsion-based compartmentalized microreactors can provide versatile platforms to efficiently control the epoxidation of styrene involving free radicals.

Aqueous-phase hydrogenation of α-pinene catalyzed by Ni-B alloys loaded on a Janus amphiphilic carbon@silica nanomaterial

A Janus amphiphilic carbon@silicon double-framework nanomaterial having an inner cavity, a hydrophobic N-doped carbon inner layer, and a hydrophilic silica outerlayer was prepared. Ni-B alloy nanoparticles were loaded on the amphiphilic carbon@silicon nanomaterial and used for catalyzing α-pinene hydrogenation in aqueous media. The hollow structure of the nanomaterial yielded a large specific surface area, which was beneficial for mass transfer and substrate enrichment, the doping of N atoms in the inner carbon skeleton allowed the attachment of additional metal nanoparticles, and the hydrophilic silica outer shell improved the stability and dispersion of the catalyst in the aqueous system. Crucially, in a water/oil two-phase reaction system, the amphiphilic nanocatalyst acted as a solid foaming agent, thus promoting the dissolution of H2 and substrate contact. Further, the synergy between Ni and B significantly improved the catalytic activity, and a kinetic study revealed the low activation energy for α-pinene hydrogenation over the prepared catalyst. DFT calculations indicate the transition states with low energy barriers. Further, the catalytic activity of our non-noble-metal nanocatalyst was comparable to that of noble metal Ru and Pd catalysts. Under mild conditions (80 °C, 1.0 MPa H2, 3 h), 99.0% α-pinene was converted to cis-pinane with 98.5% selectivity, and the developed amphiphilic Ni-B nanocatalyst also showed excellent recyclability as a result of the high dispersion and stability of the Ni-B nanoparticles on the carbon@silicon nanomaterial. The study provides a new green and efficient way for the deep processing and utilization of turpentine resources, and provides a guidance for the expansion of water-phase non-noble metal catalytic reaction types.

Enzymatic Cascade in a Simultaneous, One-Pot Approach with In Situ Product Separation for the Asymmetric Production of (4S,5S)-Octanediol

Stereopure aliphatic diols are an interesting class of compounds because of their potential applications as precursors for chemical catalysts, for high-value polymers, or as precursors for cyclic acetals. We present a simultaneous enzymatic two-step, one-pot cascade for the synthesis of vicinal diols with excellent de and ee values with the exemplary reaction system from butanal to (4S,5S)-octanediol. This reaction is restricted by an unfavorable reaction equilibrium. For an intensification of the reaction toward higher conversions in equilibrium and increased space time yields (STY), aqueous, microaqueous, and biphasic reaction systems for in situ product removal (ISPR) were experimentally investigated and compared. Process concepts for the purification of (4S,5S)-octanediol from each reaction system were developed and assessed in terms of product-specific energy demand. The two-phase reaction system for in situ product removal is favorable for the enzymatic reactions in terms of yield and STY at different time points. In comparison to the aqueous and microaqueous reaction systems, the specific energy demand for (4S,5S)-octanediol recovery is drastically reduced by approximately a factor of seven when performing ISPR using a biphasic system in comparison to an aqueous reaction system.

Microwave co-pyrolysis of lignite with direct coal liquefaction residue: Synergistic effects and product combustion characteristics

To effectively and cleanly handle the direct coal liquefaction residue (DCLR), a two-phase microwave reaction system was designed based on poly-generation lignite technology, that performed both individual pyrolysis and co-pyrolysis, to investigate the effect of microwave co-pyrolysis of lignite with different addition of DCLR on the pyrolysis products characteristics. The experimental results demonstrated the presence of synergism during microwave co-pyrolysis, which enhanced the condensation reaction of different free radicals, and thus increased the char (upgraded lignite, UL) yield by 6.14–10.42%. The DCLR showed excellent catalytic effects as consumable absorbents in terms of heating rate, and char and gas yields, and it eventually converted into high value-added combustible gases (CO, CH4, and H2). Furthermore, when compared to the individual pyrolysis sample and lignite, the co-pyrolysis samples’ chemical structures were progressively aromatized, and exhibited significantly lower O/C ratios, re-adsorption moisture content, and reactive groups and available sites. Moreover, the pore structures on the surface for the co-pyrolysis samples were dominated by cracks, blowholes, and open-ended fissures, which gradually decreased as DCLR contents increased. Combustion behavior and kinetic analysis confirmed that microwave co-pyrolysis changed activation energy (Ea) distribution of ULs and thus improving their combustion performance. Therefore, microwave co-pyrolysis of lignite with DCLR was an effective and economical approach for clean utilization DCLR and obtaining high-quality lignite fuel.

A two-phase reaction system for selective oxidative degradation of lignin model compounds

Lignin depolymerization through an oxidation method could provide value-added products, but it is challenging in terms of recovering catalysts or separating products in time to avoid over-oxidation. In this study, a process of selectively oxidative degradation of lignin model compounds was operated in a two-phase reaction system. Lignin model compounds of 4-benzyloxyphenol (PBP) or guaiacylglycerol-β-guaiacyl ether (GGE) in a bottom phase of 1-butyl-3-methylimidazole chloride ([BMIM]Cl) ionic liquid were selectively oxidized by H2O2 in the presence of a solid acid (SO42-/Fe2O3-ZrO2), and the degradation products immediately diffused into the upper organic solvent phase (butyl acetate). In this kind of reaction system, the yield of the products was improved due to the prolonged life of ∙OH in ionic liquid, and the product selectivity was maintained due to the timely product separation, and the ionic liquid and the catalyst were easily recycled.

Production of 12-hydroxy dodecanoic acid methyl ester using a signal peptide sequence-optimized transporter AlkL and a novel monooxygenase

In this study, a signal peptide of AlkL was replaced with other signal peptides to improve the soluble expression and thereby facilitate the transport of dodecanoic acid methyl ester (DAME) substrate into the E. coli. Consequently, AlkL with signal peptide FadL (AlkLf) showed higher transport activity toward DAME. Furthermore, the promoter optimization for the efficient heterologous expression of the transporter AlkLf and alkane monooxygenase (AlkBGT) system was conducted and resulted in increased ω-oxygenation activity of AlkBGT system. Moreover, bioinformatic studies led to the identification of novel monooxygenase from Pseudomonas pelagia (Pel), which exhibited 20% higher activity towards DAME as substrate compared to AlkB. Finally, the construction of a chimeric transporter and the expression of newly identified monooxygenase enabled the production of 44.8 ± 7.5 mM of 12-hydroxy dodecanoic acid methyl ester (HADME) and 31.8 ± 1.7 mM of dodecanedioic acid monomethyl ester (DDAME) in a two-phase reaction system.

Biodesulfurization of diesel oil in oil-water two phase reaction system by Gordonia sp. SC-10.

Different sulfur contents of diesel oils were used for biodesulfurization to study the desulfurization capacity of Gordonia sp. SC-10 in oil-water two-phase reaction system. Gordonia sp. SC-10 showed great properties in desulfurizing diesel oil with different sulfur contents. This bacterium could decrease sulfur contents in different diesel oils from 194.7 ± 3.7 to 30.4 ± 0.5mg/l and from 3035.3 ± 23.8 to 1792.8 ± 48.9mg/l, respectively. Furthermore, this bacterium could desulfurize broad range of organosulfur compounds and had strong desulfurization activity against alkylated DBTs. For low-sulfur diesel oil, sulfur could be removed from 10.2 ± 0.1 to 5.0 ± 0.1mg/l. The newly isolated bacteria Gordonia sp. SC-10 showed a good performance in desulfurizing diesel oils, and it might be a useful desulfurizing biocatalyst to enable the industrialized application of biodesulfurization process.

In vitro enzymatic synthesis of baccatin III with novel and cheap acetyl donors by the recombinant taxoid 10β-O-acetyl transferase

Despite the importance of baccatin III as a precursor to paclitaxel, a widely used chemotherapeutic agent, efficient enzymatic synthesis methods are lacking. Therefore, in this study, the recombinant taxoid 10β-O-acetyl transferase was prepared to produce baccatin III in vitro. The recombinant enzyme could use vinyl acetate, butyl acetate, sec-butyl acetate, isobutyl acetate, amyl acetate, and isoamyl acetate as novel and cheap alternative acetyl group donors to replace the expensive acetyl CoA for the enzymatic synthesis of baccatin III. A molecular docking study further confirmed that these acetyl donors could reasonably bind to the enzyme molecule. Using the aqueous two-phase bio-catalytic reaction system, hexane and ethyl acetate could increase the yield of product baccatin III by 2.8% and 1.1% respectively. This approach using novel and cheap acetyl donors is promising for the enzymatic synthesis of baccatin III for the future industrial production of paclitaxel.

Determination of adriamycin content in pectin–adriamycin conjugate in a two-phase reaction system by high-performance liquid chromatography

A newly proposed method for detecting content of adriamycin in pectin–adriamycin conjugate has been developed and evaluated. The content of adriamycin was detected by selective degradation of adramycin to adriamycinone. It was realized by a two-phase reaction system (water–chloroform reaction system), in which adriamycin was quantitatively converted to adriamycinone. Therefore, the latter can be used to calculate the precise content of adramycin in the polymer drug. To develop the method, the catalyst for degradation, the extraction solvent for adriamycinone, the temperature and time of degradation, and the ratio of pectin–adriamycin conjugate were investigated. The optimal reaction condition was as follows: 30 mg of pectin–adriamycin conjugate dissolved in 25 mL of water was added to a mixture of 25 mL of hydrochloric acid (1.5 mol/L) and 50 mL of chloroform; the mixture was heated to 40 °C to react for 1.5 h; after that, the mixture was extracted with chloroform for three times, and then the organic layer was combined and, subsequently, evaporated to remove solvent. Under this condition, adriamycinone generation rate reached 99.87%. The quantitative method was evaluated for linearity, the limit of detection (LOD) and limit of quantitation (LOQ), recovery, accuracy, robustness, and precision. The recoveries were between 99.47% and 101.07% with relative standard deviation <1.23%. The LOD and LOQ were 0.06 and 0.17 μg/mL, respectively. Compared to the traditional ultraviolet (UV) detection, this method is considered to be more precise for detecting content of adriamycin in its polymer conjugate.

Hydrogenation of bio-oil via gas-liquid two-phase discharge reaction system

Abstract In view of current technical problems of catalyst coking inactivation, poor equipment safety and large amount of hydrogen consumption, which are caused by high hydrogen pressure and operating temperature in bio-oil hydrogenation, an innovative gas-liquid two-phase discharge reaction system was constructed and applied to actualize the hydrogenation of bio-oil under catalyst-free, normal temperature and pressure conditions. Single-factor experiments were performed to explore the effects of working voltage, gas-flow rate and reaction time on the deoxygenation rate and high heating value of refined bio-oil. Furthermore, with the results of multi-factor orthogonal experiments, the operating parameters optimization model for the deoxidation rate of bio-oil was developed. The reasonable reaction pathways for the hydrogenation of various oxygenated compounds under gas-liquid two-phase discharge reaction conditions were well inferred. Under optimized operating parameters, the deoxidation rate of 65.26% with the high heating value of 35.15 MJ/kg of bio-oil were achieved. GC–MS analysis results demonstrated that aldehydes, ketones were completely diminished, and alcohols, esters, phenols and acids were decreased. A remarkable increase of hydrocarbons was revealed, which indicated the quality of bio-oil was significantly improved. As a result, this gas-liquid two-phase discharge reaction system can perform hydrogenation of bio-oil efficiently.

Estimation of Overall Transesterification Rate of Palm Oil in Oil- Methanol Two-Phase Reaction System - Does The Mass Transfer Matter? -

This paper aims to formulate a model describing the overall transesterification rate of vegetable oil with methanol catalyzed by homogeneous catalyst. Transesterification of palm oil with methanol catalyzed by KOH was carried out in a laboratory scale batch reactor at 298, 308 and 323 K. The stirring speed of the reaction mixture was chosen at a level, at which methanol droplet external mass transfer may be negligible. The internal mass transfer was analyzed by applying the effectiveness factor concept developed for solid-fluid heterogeneous catalytic reaction system. The internal mass transfer was found to be negligible in this reaction system under the conditions applied in the present study. The authors reproduced the overall two-phase transesterification rate from homogeneous transesterification kinetic data and some required parameters by applying the model proposed in the present study. The factors which suppress the overall two-phase reaction rate are solubility of oil in methanol and methanol to oil volume ratio.

A two-phase system for the clean and high yield synthesis of furylmethane derivatives over –SO3H functionalized ionic liquids

A new and effective unique two-phase reaction system for the high yield production of tri(furyl)methane from furfural and furan.

Strong quantum confinement effect in Cu4SnS4 quantum dots synthesized via an improved hydrothermal approach

We developed an improved hydrothermal method with water-oil two-phase reaction system to synthesize size-controllable and oil-soluble Cu4SnS4 (CTS) quantum dots (QDs). The water-oil interface played an important role in controlling nuclei process, growth speed, crystal size and size-distribution of CTS QDs. X-ray diffraction, Raman scattering and transmission electron microscopy studies suggested that the formation and growth mechanism of CTS QDs was revealed to involve three steps. The crystallographic orientation of the CTS nanoprism was analyzed in detail. The blue-shift of absorption edge and broadening of Raman bands were observed due to the quantum confinement effect. The exciton Bohr radius of CTS QDs was calculated to be 3.3–5.8 nm by using the first principle calculation. The size dependence of band-gaps of CTS QDs follows the particle-in-a-box effective-mass model. The ability to fabricate high-quality CTS QDs certainly facilitates the solar cell applications.

Electrostatic Trapping of Double-Stranded DNA Based on Cd(OH)2 Three-Side Nanobelt Architectures

In this paper, Cd(OH)2 1D three-side nanobelt architectures have been fabricated through a facile two-phase reaction system. Considering their electropositive character proven by zeta potential measurement, the as-obtained Cd(OH)2 nanomaterials have been applied to capture negatively charged DNA. On the basis of the above results, the Cd(OH)2 nanomaterials have been employed for trapping negatively charged double-stranded DNA molecules (salmon sperm DNA). Assisted by the detailed observation of their DNA interaction results as well as through UV–vis spectroscopy, infrared imaging automatic target recognition (IRATR) and inductive coupled plasma atomic emission spectrometer (ICP-AES) measurements, it has been clearly shown that this 1D nanoarchitecture can effectively trap and release DNA molecules without use of any other organic reagents. In addition, a miniaturized electrochemical DNA-releasing device based on the Cd(OH)2 1D three-side nanobelt architectures has been fabricated. Using this device, it is...

Biosynthesis of myristyl serinate by immobilized Candida antarctica lipase in two-phase system

The significance and novelty of this manuscript is that myristyl serinate was firstly synthesized from myristyl alcohol and l -serine using lipase catalyzed esterification in selected solvents. The effects of reaction system, two-phase system composition, temperature, pH, and reaction time on myristyl serinate ester content in the crude reaction mixture were investigated. The results showed that two-phase could significantly increase the enzymatic interesterification conversion and the optimal ratio of two-phase solvent was 80:20 (dichloromethane:phosphate buffer). The optimal conditions for myristyl serinate enzymatic synthesis were substrate molar ratio of 1:1, Novozym 435 load of 5% (w/w), a solvent dosage of 20 ml, 30 °C and reaction time of 36 h. Myristyl serinate content could reach 72.25% in the reaction system. Myristyl serinate was purified through column chromatography and identified by HPLC/IR/LC-MS/NMR. • Myristyl serinate was firstly enzyme-synthesized in selected solvents. • Two-phase could significantly increase the enzymatic esterification conversion. • The optimal ratio of two-phase was 80:20 (dichloromethane:phosphate buffer). • Myristyl serinate content reached 72.25% in the system under optimal conditions. • Myristyl serinate was purified, determinated and identified by HPLC/IR/LC-MS/NMR. Myristyl serinate was firstly enzyme-synthesized from myristyl alcohol and l -serine in selected solvents (single and two-phase solvents). The effects of reaction system, two-phase system composition, temperature, pH, and reaction time on myristyl serinate synthesis were investigated. The results showed that two-phase solvent reaction system could significantly increase the enzymatic conversion ratio and the optimal ratio of two-phase solvent was 80:20 (dichloromethane:phosphate buffer). The optimal conditions for myristyl serinate enzymatic synthesis were substrate molar ratio of 1:1, Novozym 435 load of 5% (w/w), a solvent dosage of 20 ml, 30 °C and reaction time of 36 h. Under these conditions, 72.25% of myristyl alcohol could be converted to myristyl serinate, which was purified through column chromatography and identified by HPLC/IR/LC-MS/NMR.