AbstractA one-pot three component reaction of benzaldehydes, 1H-tetrazole-5-amine, and 3-cyanoacetyl indole in the presence of a new hexamethylenetetramine-based ionic liquid/MIL-101(Cr) metal–organic framework as a recyclable catalyst was explored. This novel catalyst, which was fully characterized by XRD, FE-SEM, EDX, FT-IR, TGA, BET, and TEM exhibited outstanding catalytic activity for the preparation of a range of pharmaceutically important tetrazolo[1,5-a]pyrimidine-6-carbonitriles with good to excellent yields in short reaction time.
Novel flower-shaped C-dots/Co3O4{111} with dual-reaction centers were constructed to improve the Fenton-like reaction activity and peroxymonosulfate (PMS) conversion to sulfate radicals. Due to the exposure of a high surface area and Co3O4{111} facets, flower-shaped C-dots/Co3O4{111} could provide more Co(II) for PMS activation than traditional spherical Co3O4{110}. Meanwhile, PMS was preferred for adsorption on Co3O4{111} facets because of a high adsorption energy and thereby facilitated the electron transfer from Co(II) to PMS. More importantly, the Co–O–C linkage between C-dots and Co3O4{111} induced the formation of the dual-reaction center, which promoted the production of reactive organic radicals (R•). PMS could be directly reduced to SO4−• by R• over C-dots. On the other hand, electron transferred from R• to Co via Co–O–C linkage could accelerate the redox of Co(II)/(III), avoiding the invalid decomposition of PMS. Thus, C-dots doped on Co3O4{111} improved the PMS conversion rate to SO4−• over the single active site, resulting in high turnover numbers (TONs). In addition, TPR analysis indicated that the optimal content of C-dots doped on Co3O4{111} is 2.5%. More than 99% of antibiotics and dyes were degraded over C-dots/Co3O4{111} within 10 min. Even after six cycles, C-dots/Co3O4{111} still remained a high catalytic activity.
Dehydration of n-butanol (nB) to corresponding olefins (butene) is an important reaction route to realize the efficient utilization of bulk bio-alcohols. In this work, a novel phosphate modified oxidized multi-walled...
Novel tetracarboxyl-functionalized 2,2′-biimidazolium-based ionic liquids (ILs) with different anions were synthesized in two steps from readily available and sustainable starting materials including ammonium acetate, glyoxal, and halogenated propionic acid. The functionalized IL exhibited higher catalytic activity towards the cycloaddition of CO2 to terminal epoxides. With propylene oxide as a substrate, the optimum yield of propylene carbonate reached 82.7 % at an initial CO2 pressure of 2.0 MPa for 4 h at 140°C. Moreover, the functionalized IL catalyst displayed a high stability and can be reused for at least five cycles without obvious loss of catalytic activity. The results provide a simple and economical way to synthesize multi-functionalized imidazolium-based ILs with versatile potential applications.
The calcium phosphate tungsten bronze (Ca-PWB) has been synthesized and
characterized (TGA, DSC, XRPD, FTIR, SEM). The influence of solid insoluble
materials Ca- PWB, as well as lithium doped (Li-PWB) and cation free
phosphate tungsten (PWB) bronzes on the oscillatory Briggs-Rauscher (BR)
reaction dynamics, is compared. The results show that doping with Li and Ca
reduces sensitivity of the BR reaction towards bronzes addition. These
findings suggest the usage of the BR reaction as an innovative method for
testing of different properties of bronze material. The behavior of PWB in
the BR reaction is significantly changed with divalent cation (Ca2+) doping.
The reasons for the different bronzes behavior were found in their
calculated unit cell volumes. Namely, the compressed Ca-PWB unit cell volume
indicates the difficult availability of the active site for heterogeneous
catalysis. Hence, the linear correlation (slope) of the BR oscillogram?s
length (?osc) vs. mass of bronze in BR reaction might be considered as a new
parameter for the evaluation of the bronzes catalytic activity.
Synthesis of tetrazolo[1,5-a]pyrimidine-6-carbonitriles using HMTA-BAIL@MIL-101(Cr) as a superior heterogeneous catalyst