Continuous flow ZIF-8/NaA composite membrane microreactor for efficient Knoevenagel condensation

Zhang, Guangcai; Zhang, Tong; Zhang, Xiongfu; Yeung, King Lun

doi:10.1016/j.catcom.2015.05.008

Cited by 30 publications

(9 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, mostly inorganic-based materials are used as carrier for catalysts. [20][21][22][23][24] This approach can easily been used, however, forces an inaccessible volume within the reactor chamber due to the solid carrier material (Figure 1: blue area). To overcome the limitations given by inaccessible volume swollen polymer networks (gels) were used as carriers.…”

Section: Introductionmentioning

confidence: 99%

“…In general, inorganic materials or polymers as carriers are mostly used within packed-bed flow reactors. [18,[20][21][22][23][25][26][27]29,30] This type of reactors often uses column-like reactor chambers which require a large amount of catalytically active material [29,30] and/or a complex set up with high pressure pumps to enable the flow rate due to the tight packing. [18,25] However, high pressure is tough to apply properly due to collapsing and deactivation of poorly cross-linked swollen gels during the flow reaction.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Novel Application of Polymer Networks Carrying Tertiary Amines as a Catalyst Inside Microflow Reactors Used forKnoevenagelReactions

et al. 2020

View full text Add to dashboard Cite

A novel application is described for utilizing hydrogel dots as organocatalyst carriers inside microfluidic reactors. Tertiary amines were covalently immobilized in the hydrogel dots. Due to the diffusion of reactants within the swollen hydrogel dots, the accessible amount of catalysts inside a microfluidic reactor chamber can be increased compared to the accessible amount of surface‐bound catalysts. To perform fast Knoevenagel reactions, important flow parameters had to be validated to optimize the reactor performance while keeping the dimensions of the reactor chamber constant; e.g. the height of the hydrogel dots had to be adjusted to the invariable dimensions of the reactor chamber, or an adjustment of organocatalysts in the hydrogel dots had to be validated to achieve the highest conversion rate during a certain residence time. To characterize the conversion, nuclear magnetic resonance (NMR) and UV/Vis‐spectroscopy were utilized as an offline and online method, respectively. With suitable hydrogel dots, the influence of different flow parameters (e.g., operating flow rate and reactant concentration) on the selected model reactions in the microfluidic reactor was investigated. Finally, a variety of reactants were screened with the optimized flow parameters. With these results, the turnover frequency was determined for the Knoevenagel reactions in a microfluidic reactor, and the results were compared with published data that were determined by other synthetic approaches.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Novel Application of Polymer Networks Carrying Tertiary Amines as a Catalyst Inside Microflow Reactors Used forKnoevenagelReactions

et al. 2020

View full text Add to dashboard Cite

show abstract

“…ZIF‐8 itself has both nitrogen basic sites and Zn II Lewis acidic sites and has been extensively used to construct versatile nanoparticle composites with metal or metal oxides, silica, organic polymers, quantum dots (QDs) and graphene toward diversiform structures for desired properties . Through compositing with proper species, the active sites on ZIF‐8 enable the activation of substrates to facilitate different type organic transformations such as the Knoevenagel condensation, CO 2 cycloaddition of epoxides, conjugate‐addition reaction, and so on.…”

Section: Introductionmentioning

confidence: 99%

Mechanically fabricated Metal–organic framework/resin composite nanoparticles for efficient basic catalysis

Zhang

Qian

Sheng

et al. 2019

Applied Organom Chemis

View full text Add to dashboard Cite

Zeolitic imidazolate framework‐8 (ZIF‐8) was successfully composited with an anionic basic resin 201 × 7 (717‐resin) to provide a novel ZIF‐8/717‐resin composite. Its catalytic activity toward the Knoevenagel condensation reaction was evaluated. Results showed that ZIF‐8/717‐resin composite could efficiently catalyze this reaction, affording the corresponding products in good to excellent yields. Good functional group tolerance, mild reaction conditions, good stability and reusability of the catalyst are the major features of present protocol.

show abstract

“…For example, Wiles et al [ 13 ] utilized 3-(1-piperazino)propyl-functionalized silica gel as the catalyst, and EOF-based micro-fabricated device as the flow reactor for Knoevenagel condensation reaction, presenting high yields (>99%) and product purity in all cases. Zhang et al [ 14 ] have fabricated a stable ZIF-8/NaA composite membrane microreactor for the continuous flow Knoevenagel condensation, achieving nearly 100% product yield in a short residence time under mild conditions. Tsutsumi et al [ 15 ] prepared a basic nanofibrillar chitin aerogel as the renewable catalyst for Knoevenagel condensation, which presented high performance in flow mode.…”

Section: Introductionmentioning

confidence: 99%

Amine-Functionalized Sugarcane Bagasse: A Renewable Catalyst for Efficient Continuous Flow Knoevenagel Condensation Reaction at Room Temperature

et al. 2017

View full text Add to dashboard Cite

A biomass-based catalyst with amine groups (–NH2), viz., amine-functionalized sugarcane bagasse (SCB-NH2), was prepared through the amination of sugarcane bagasse (SCB) in a two-step process. The physicochemical properties of the catalyst were characterized through FT-IR, elemental analysis, XRD, TG, and SEM-EDX techniques, which confirmed the –NH2 group was grafted onto SCB successfully. The catalytic performance of SCB-NH2 in Knoevenagel condensation reaction was tested in the batch and continuous flow reactions. Significantly, it was found that the catalytic performance of SCB-NH2 is better in flow system than that in batch system. Moreover, the SCB-NH2 presented an excellent catalytic activity and stability at the high flow rate. When the flow rate is at the 1.5 mL/min, no obvious deactivation was observed and the product yield and selectivity are more than 97% and 99% after 80 h of continuous reaction time, respectively. After the recovery of solvent from the resulting solution, a white solid was obtained as a target product. As a result, the SCB-NH2 is a promising catalyst for the synthesis of fine chemicals by Knoevenagel condensation reaction in large scale, and the modification of the renewable SCB with –NH2 group is a potential avenue for the preparation of amine-functionalized catalytic materials in industry.

show abstract

Continuous flow ZIF-8/NaA composite membrane microreactor for efficient Knoevenagel condensation

Cited by 30 publications

References 18 publications

Novel Application of Polymer Networks Carrying Tertiary Amines as a Catalyst Inside Microflow Reactors Used forKnoevenagelReactions

Novel Application of Polymer Networks Carrying Tertiary Amines as a Catalyst Inside Microflow Reactors Used forKnoevenagelReactions

Mechanically fabricated Metal–organic framework/resin composite nanoparticles for efficient basic catalysis

Amine-Functionalized Sugarcane Bagasse: A Renewable Catalyst for Efficient Continuous Flow Knoevenagel Condensation Reaction at Room Temperature

Contact Info

Product

Resources

About