Abstract:In order to accelerate our country's achieving the goal of "double carbon" in advance, and deeply implement the important measures of green, low-carbon and sustainable development of the chemical industry, recent studies show that adsorption-absorption coupling separation technology is expected to be a green and revolutionary separation technology for gas separation, the key to which is the development of high-performance adsorption materials. As a liquid material with permanent porosity, porous liquids (PLs) combine the advantages of liquid absorbents (e.g., easy pipeline transportation, favorable mass and heat transfer, high specific surface area, etc.) with those of solid adsorbents (e.g., high porosity) and are expected to be a new generation of green, transformative media for CO2 capture. Here, first, the developmental lineage of PLs is presented, followed by a summary and detailed discussion of the applications of PLs in CO2 adsorption, membrane separation, and catalytic conversion. And summarize the performance and advantages and disadvantages of porous liquids. Finally, the challenges and difficulties faced by PLs are presented as future trends.

Abstract:Nanosilver is one of the most widely researched and applied nanomaterials. In recent years, in order to avoid toxic by-products in the synthesis of nanosilver, many studies have been done in the green synthesis of nanosilver. All kinds of natural compounds rich in plant tissues and microbial cells can complete the green synthesis of nanosilver, and the potential of nanosilver synthesis from different biological sources needs to be further explored. The controllability of the size and shape of nanosilver, as well as the reduction of migration and side effects under the premise of making nanosilver play an antibacterial role, are the next priorities. The mechanism and method of using plant, bacteria and fungal green synthesis of nanosilver are reviewed, the methods are analyzed and compared, the antibacterial performance, antibacterial mechanism and specific application of nanosilver are introduced, and suggestions are made for future development.

Abstract:Porous Liquids (PLs) is a new type of liquid material that combines the permanent porosity of porous solid materials and liquid fluidity, showing great potential for gas adsorption and separation, catalysis and other applications. Metal framework materials (MOFs) are expected to become one of the best candidates for constructing porous hosts for PLs due to their high specific surface area, thermal and chemical stability, unique structure, and simple preparation. In recent years, MOFs (ZIF-8, ZIF-67, UiO-66, etc.) based porous liquid related research has been continuously reported. First, the classification of porous liquids was presented. Secondly, we summarize the preparation of MOFs-based porous liquids and its applications in recent years. Finally, the challenges in the preparation of MOFs-based porous liquids and the future in the areas of gas adsorption and catalysis are prospected and summarized

Abstract:Metal-Organic Frameworks (MOFs) are a new class of porous crystalline materials with periodic mesh structures, which are synthesized by the coordination of inorganic metal ions or ionic clusters with organic ligands. Among many MOFs materials, Fe-based Materials of Institute Lavoisier Frameworks (MILs) are widely used in medicine, sensing, catalysis and other fields due to their excellent biocompatibility, unique skeleton flexibility, outstanding specific surface area and high stability. In order to further enhance the practical applications of Fe-based MILs and related materials and expand their application scopes, the structures and properties of Fe-based MILs are generally optimized via innovative synthesis methods, structural modifications, and compounding with other materials. In the present paper, the classification and structural characteristics of Fe-based MILs were discussed. Additionally, the common syn-thesis and modification methods of Fe-based MILs are reviewed, and the applications of Fe-based MILs in drug carriers, sensing, adsorption, and catalysis are summarized. Finally, the advantages and limitation of Fe-based MILs are discussed, and their development trends are prospected.

Abstract:Zirconium-based metal-organic frameworks (Zr-MOFs) possess excellent advantages of large surface area, high porosity, easy functionalization, simple and rich synthesis methods, and outstanding stability, which manifest great application potential in the fields of gas adsorption and separation, catalysis, and sensing. The appropriate level of defects can change physicochemical properties without destroying the structure of Zr-MOFs, significantly improving adsorption and catalysis performance. The structure of defects can be modulated using defect engineering, and the precise defect information can be obtained through a combined use of different characterization techniques, which accelerate the practical applications of defective Zr-MOFs in specific fields. Herein, defect modulation strategies such as template method and post-synthetic modification method, and defect characterization techniques of Zr-MOFs are discussed in detail, the advantages and disadvantages of different techniques are further discussed. Progress on defective Zr-MOFs in the field of chemical defense has been reviewed, including adsorption of toxic industrial chemicals, catalytic degradation of chemical warfare agents, gas sensing and separation, and their future developments are prospected.

Abstract:Liquid crystal elastomers (LCEs) are a kind of slightly cross-linked polymer network containing liquid crystal units, which combine the soft elasticity of polymer networks with the anisotropy of liquid crystal substrates Note that LCEs realize non-contact motion under the stimulation of external environment via using program molecular orientation, which exhibiting excellent elasticity and drive performances. These results further verify LCEs possess great potential in practical applications of artificial muscles, software robots and wearable devices. Liquid crystal elastomer fibres, as a common form of LCEs, exhibit broad application prospects in many fields due to its higher orientation of the liquid crystal substrates within the fiber, more sensitive response to various stimulation, good programmability and excellent mechanical strength. This paper reviews the main preparation methods of liquid crystal elastomer fibers, analyzes the driving response mechanism to different types of stimuli, systematically introduces the classification of photo-responsive liquid crystal elastomers, and elucidates the photothermal conversion process and the remote drive regulation mechanism. In addition, the liquid crystal elastomer fiber systems with different driving modes are analyzed, and the latest research progress in the fields of flexible sensing, intelligent driving, biomimetic, and artificial muscle of fiber-wiper LCEs composites are briefly discussed, and its development prospect is also prospected in this paper.

Abstract:Nepenthes pitcher plant, its special wetting structure were used to capture insects for supplying nutrients, which inspiring researchers infused lubricant with low surface energy to preparation slippery liquid-infused surface. Compared with superhydrophobic surface, it has more durable characteristic such as hydrophobicity, self-cleaning, anti-adhesion and etc, hence it has become a research hotspot. Based on above mentioned, firstly, the wetting theory and mechanism of action of biomimetic super-slippery were introduced. Secondly, the construction strategy of super-slippery surface was reviewed in detail, including two basic path, one type is rough substrate forming-lubricating oil infusion; other type is rough substrate forming-chemical modification of substrate-lubricating oil infusion. A series of preparation method of super-slippery surface such as etching, sol-gel, breath figure, hydrothermal, were also discussed comprehensively. In view of the excellent properties of super-slippery surface, its application progress in the fields of oil-water separation, fog collection, anti-corrosion, droplet manipulation, anti-biofouling and bacterial adhesion were expounded in depth. Finally, the prospect of biomimetic super-slippery surfaces is prospected, in order to bring reference for future research.

Abstract:A series of polyetherimides PEI-ABx (x were 0%, 5%, 10%, 15% and 20%, respectively, indicating the content of ATHDA based on the total mass of BPADA and ODA) were synthesized from AB-type monomer 3-amino-5,6,9,10-tetrahydro-[5]helicene-7,8-dicarbonyl-dicarboxylic anhydride (ATHDA), 4,4'-(4,4'-isopropylidenediphenyloxy) bis-(phthalic anhydride) (BPADA) and 2-aminodiphenyl ether (ODA). The polymers were characterized by FTIR, 1HNMR, DSC, DMA and TGA. The results showed that the inherent viscosity numbers of the PEI-ABx were 0.60~0.87 dL/g. All of the polymers had good film-forming property and solubility. The glass transition temperatures (Tg) measured by DMA were 228~256 °C, and the 5% thermogravimetric temperatures (T5%) were 505~536 °C in N2 atmosphere, which indicated that the PEI-ABx had excellent thermal stability. The tensile strength, young's modulus and elongation at break of the polymer films were 41.7~88.1 MPa, 1.7~2.7 GPa and 3.3%~4.8%, respectively, demonstrating that the PEI-ABx possessed good mechanical properties. In addition, the tetrahydro - [5] helicene structure in polymer chains could be dehydrogenated to form more rigid aromatic structure. For PEI-AB20%, after dehydrogenation the Tg and T5% of the polymer were increased from 256 °C to 283 °C, and 531 °C to 557 °C respectively. The results showed that the heat resistance of the polymers could be further improved by dehydrogenation.

Abstract:The composite aerogel fibers were prepared with green organic material bacterial cellulose and doped with reinforcing material thermoplastic polyurethane elastomer using wet spinning. The prepared aerogel fibers were structurally analyzed and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), automatic specific surface porosity analyzer and monofilament strength meter, and the results showed that the composite aerogel fibers have porous structure, good mechanical properties and thermal insulation, with a breaking strength of 24.69 Mpa and an elongation at break of 38.54%.

Abstract:Carboxymethyl chitosan-castor oil-based polyurethane microspheres (CO-CMCS-PU) were prepared from carboxymethyl chitosan (CMCS), castor oil (CO) and isophorone diisocyanate (IPDI) by self-emulsification, and drug-loaded microspheres (CO-CMCS-PU@AVM) were obtained by loading avermectin (AVM) by molecular self-assembly. The structure and morphology of the product were characterized by FTIR, 1HNMR, SEM and TGA, and the encapsulation efficiency, slow-release performance, anti-ultraviolet performance, leaf contact angle and adhesion performance of drug-loaded microspheres with different doses were explored. The results showed that compared with AVM dispersion, the retention rate of AVM in drug-loaded microspheres increased to 43% after ultraviolet irradiation, which indicated that CO-CMCS-PU carrier had good ultraviolet resistance. Compared with AVM dispersion, the contact angle of drug-loaded microspheres on cucumber leaves decreased by more than 20%, and the retention capacity increased by more than 40%, which indicated that they had good adhesion and wettability on cucumber leaves. The encapsulation efficiency of drug-loaded microspheres can reach more than 80%, which has good slow-release and pH-responsive release performance. The drug release behavior conforms to the First-order kinetic model, and the drug release is controlled by Fickian diffusion.

Abstract:A mechanochemical in-situ solid-state reaction synthesis method for Si-based composites was developed. This method involves milling excess micron-Si and Ag2O to form SiO and Ag particles in-situ and adhere to the matrix Si during the ball-milling crushing process (abbreviated as Si/( SiO + Ag )). Carbon-coated Si-based composites Si/( SiO + Ag ) - C were prepared using asphalt as a carbon source by high-temperature calcination. Both of these composites exhibit excellent rate performance, exhibiting reversible specific capacities of 1422 and 1039 mA h/g at low current density (0.12 A/g), respectively, while 672 and 393 mA h/g can still be obtained at high current density (2.4 A/g); When the current density is restored to 0.12 A/g again, the reversible capacity can be restored to 1329 and 961 mA h/g. In contrast, Si/(SiO + Ag ) - C exhibit better cycle stability, and their capacity remains stable above 943mA h/g after 80 cycles. This outstanding rate performance is attributed to the refinement of Si-based particles and the electrical conductivity of in situ-formed nano-Ag particles, while the improvement in cycle stability is related to the dual-phase buffer structure composed of in situ-formed SiO and coated carbon.

Abstract:Nonylphenol ethoxylate is in urgent need of extensive research on alternatives due to its aquatic toxicity. Nonyl cyclohexanol ethoxylates have been considered as potential alternatives with a higher safety profile and similar physicochemical properties to nonylphenol ethoxylates. In this research, sodium nonylcyclohexanol ethoxylates sulfate were synthesized by using nonylcyclohexanol ethoxylates as raw material and chlorosulfonic acid as sulfation reagent, in which the esterification rates toward sodium nonylcyclohexanol ethoxylate (5) sulfate and sodium nonyl cyclohexanol ethoxylate (9) sulfate (5, 9 represents the number of ethylene oxide addition) could reach 90.91% and 91.06%, respectively. The results indicate that the aqueous solution of sodium nonylcyclohexanol ethoxylate (5) sulfate exhibited similar interfacial activity as sodium alkyl ethoxylate (3) sulfate (AES). In short, sodium nonylcyclohexanol ethoxylates sulfate presents comparable wetting and foaming properties as nonylcyclohexanol ethoxylates do, and better wetting, foaming as well as emulsifying performance than AES does.

Abstract:The traditional synthesis method of (S)-nicotine suffers from complex steps and relies on multiple chemical catalysts. In order to realize the green synthesis of (S)-nicotine, a chemoenzymatic cascade pathway was designed in this study. Firstly, a coupling system of imine reductase (IRED) and formate dehydrogenase (FDH) was constructed to synthesize (S)-nornicotine using myosmine as the substrate; then (S)-nicotine was prepared via the Eschweiler-Clarke reaction of (S)-nornicotine. The enzyme-containing cells and enzyme solution were obtained via the expression of IRED and FDH in E. coli hosts and the effects of pH and temperature on the enzyme activity of IRED and FDH were investigated. The reaction conditions for the enzymatic synthesis of (S)-nornicotine were optimized, and the yield of (S)-nornicotine was>98% with enantiomeric excess (e.e.) value of >99% at 30 ℃ and pH 7.5 with the addition of myosmine at a mass concentration of 30 g/L, 600 U/L IRED-containing cells, 900 U/L FDH-containing cells, 0.6 mmol/L NADP+ and sodium formate at a mass concentration of 90 g/L. Finally, (S)-nicotine was obtained by chemical methylation of (S)-nornicotine, with a yield and e.e. value of above 99%.

Abstract:Objective: This study aimed to optimiz the extraction process of polysaccharide from the seeds of Trichosanthes Kirilowii Maxim and investigate the primary structure and hypoglycemic activity of polysaccharide. Methods: The extraction process of polysaccharide from seed of Trichosanthes Kirilowii Maxim was optimized by hot water extraction. The homogenous polysaccharide (WHP-I) was purified by dextran gel G-150, and its structure was characterized. The hypoglycemic activity of Trichosanthes Kirilowii seed polysaccharide was investigated by in vitro and in vivo experiments. Results: The optimal conditions for extracting polysaccharide from Trichosanthes Kirilowii seed by hot water extraction were 80℃, 100 min, 1:25 solid-liquid ratio (g/mL), and two times of extraction. Verification test results showed that the extraction rate of polysaccharide was 17.54%, and the optimal scheme was scientific and reasonable. The primary structure analysis showed that WHP-I had an average molecular weight of 47.65 kDa and contained five sugar residues: →3)-Araf-(1→,→6)-Galp-(1→,→4)-Glcp-(1→, D-Glcp-(1→,and →4,6)-D-Glcp-(1→. The surface of WHP-I was flat, with pore structure and fine particles attached to the surface. The results of in vitro hypoglycemic experiment showed that the IC50 value of WHP-I inhibited α-glucosidase was 16.837 mg/mL. In vivo experiments showed that WHP-I has the potential to slow the organ damage caused by T2DM. After 4 weeks of administration, the blood glucose levels of M-WHP-I group and H-WHP-I group were reduced by 32.13% and 42.27%, respectively. Moreover, WHP-I could repair the kidney and liver of diabetic mice. Conclusion: The optimized process of polysaccharide from the seeds of Trichosanthes Trichosanthes Kirilowii was reasonable and feasible, with clear structure and obvious hypoglycemic activity.

Abstract:Using iodoarenes as arylation reagents, Pd-catalyzed sulfonyl group-directed selectively C-Harylation of indoles was investigated in detail. The results showed N-tosyl indole can be converted into 2- and 7-arylated products with an overall yield of 93% in 1, 4-dioxaneat 120 ℃for 24 h with Pd(OAc)2/PPh3 as the catalyst, Na2CO3 as the base and Ag2CO3 as the additive. Under these optimized conditions, the scope and limitation of the synthetic method were examined by using different aryl iodides to obtain 28 indole-based compounds in 22%~93% total yields, and the structure of corresponding indole products were elucidated by 1H NMR, 13C NMR and HRMS spectra.

Abstract:Using high degree of polymerization ammonium polyphosphate (APP) as a flame retardant and polyvinyl alcohol (PVA) as a film-forming framework material, a PVA/APP modified separator was prepared through phase conversion method and used in lithium batteries. Characterize the mechanical strength, wettability, thermal stability, microstructure, and electrochemical performance of the modified separator. Explore the effect of different APP additions on the performance of the separator and evaluate the cycling rate performance of its assembled battery. The results showed that when the PVA mass fraction was 10% and the APP addition was 8%, the modified separator had excellent electrolyte wettability and thermal stability, with a liquid absorption rate of 215% and almost no shrinkage at 200 ℃; The tensile strength reaches 47.4 MPa. The battery was assembled using a modified separator and cycled 50 times under a discharge condition of 0.1 C. The specific discharge capacity was 143.2 mAh/g, and the Coulombic efficiency was higher than 97%. The capacity retention rate reached 95.1%, while the capacity retention rate of the battery assembled with a commercial lithium battery separator was only 82.8%. The modified separator has flame retardant properties while maintaining good electrochemical performance in the assembled battery.

Abstract:Steroid estrogens (SEs) are a kind of emerging and harmful pollutants that have garnered worldwide attention. Traditional wastewater treating methods generally fail to eliminate them entirely. Humic acid (HA), as an electron transport mediator, can significantly improve the electron transport efficiency of extracellular respiration during microbial metabolism. In view of the special electrochemical properties of HA, its application to microbial fuel cell (MFC) systems is expected to achieve efficient degradation of SEs with low energy consumption. In this study, the MFC anode was modified with a metal compound (HA@Fe3O4) formed by HA and strong capacitive nano-Fe3O4 particles. 17α-ethynylestradiol (EE2) was selected as the representative SEs to evaluate the degradation performance of the modified MFC anode. The results showed that the presence of HA not only increased electron transfer efficiency between microorganisms and the anode, but also enhanced the electric production performance by improving the anode"s capacitance. The maximum power density in the MFC system increased to 522.32 mW/m2 after the combination of HA. Also, the anode modified with HA@Fe3O4 could significantly improve the degradation efficiency of EE2 by MFC. Additionally, EE2 at low concentrations promoted the performance of MFC, but inhibited the activity of microorganisms and reduced the electricity generation efficiency of MFC at high concentrations. This study provided a certain research basis for the effective application of MFC in actual wastewater.

Abstract:This paper investigated the denitrification performance and stability of aerobic granular sludge (AGS) for treating inorganic wastewater with high ammonia nitrogen in a continuous flow reactor. The reactor was started by seeding with mature AGS. The influent nitrogen loading rate was gradually increased from 1.0 kgm-3d-1 to 4.0 kgm-3d-1 in the former 55 days, gradually decreased to 1.4 kgm-3d-1 in days 56~125, and then increased to 2.0 kgm-3d-1 again in days 126~145. In the former 75 days, obvious particle breakage and sludge loss were observed, and the average particle size decreased continuously. Although seed AGS was supplemented several times to maintain the stability of the system, the sludge volume index (SVI), extracellular polymeric substance (EPS) and specific oxygen uptake rate (SOUR) of the granules fluctuated sharply in the former 90 days. Affected by the epidemic, the reactor was idled in situ in days 91~109. After re-startup, the physical and chemical indexes of AGS tended to be stable gradually. The removal efficiency of NH4+-N gradually increased to more than 98% in the former 45 days, rapidly decreased to approximately 50% in days 46~75, and then rose to more than 99% again. The total inorganic nitrogen removal efficiency was between 35% and 45% in most of the days. The selective screen of sludge was investigated by sludge interception test. When the depth of the baffle in the sedimentation tank was 27 cm, the sludge retention rate of the reactor was above 98%, and the particle size of sludge in effluent was mostly between 0 and 0.30 mm. The microbial community of sludge was analyzed by high throughput sequencing. Compared with the seed AGS, the relative abundance of nitrifying bacterial genus (Nitrosomonas) in AGS on day 145 increased significantly, while the relative abundance of denitrifying bacterial genera (such as unclassified_Flavobacteriaceae, unclassified_Xanthomonadaceae and Thauera) decreased slightly.

Abstract:In order to improve the grafting modification degree and flame retardant effect of adenosine phosphate monomer on cotton fabric, glycyl methacrylate (GMA) was used to modify adenosine monophosphate (AMP), adenosine diphosphate (ADP) and adenosine triphosphate (ATP), obtaining three kinds of flame retardant monomers of AMP-m-GMA, ADP-m-GMA and ATP-m-GMA with unsaturated double bond. Subsequently, three flame retardant monomers were grafted onto cotton fabric via UV photografting to prepare photografted flame retardant cotton fabrics with AMP-m-GMA, ADP-m-GMA and ATP-m-GMA, respectively. The structure characterization and thermal stability analysis of three flame retardant monomers were carried out, and the thermal stability, flame retardant performance, combustion behavior and structure of residual carbon of three photografted flame retardant cotton fabrics were investigated. The results showed that unsaturated double bonds were introduced onto three adenosine phosphate monomers with good thermal stability through ring-opening reaction of epoxy group of GMA. Compared with pristine cotton fabric, the maximum thermal degradation rate of three kinds of flame-retardant cotton fabrics decreased by 60.0%, 52.0% and 60.0%, the limit oxygen index increased from 16.1% to 25.39%, 27.38% and 26.38%, and the heat release rate of the fabrics decreased by 15.09%, 60.47%, 37.82%, respectively. These results implied that three flame retardant adenosine phosphate monomers could help cotton fabric form dense carbon layer, prevent heat diffusion, and obtain good flame retardant effect. Among three photografted flame retardant cotton fabrics, the weight gain rate of ADP-m-GMA flame retardant cotton fabric could reach 22.4% and the damage length after burning was reduced from 30 cm to 14.2 cm, demonstrating better flame retardancy.

Abstract:Abstract: An associated salt-tolerant polymer p(AM/AMC12S/GTE-10) was prepared by reverse-phase emulsion polymerization using acrylamide (AM), 2-acrylamide-sodium dodecyl sulfonate (AMC12S) and hydrophobic monomer GTE-10 as materials. The structure and rheological properties were characterized by FTIR, 1HNMR, SEM, TEM and laser particle size analyzer. The results showed that the hydrophobic monomer GTE-10 was successfully introduced into the polymer, and the particle size distribution of the emulsion after polymerization was concentrated and uniform. The addition of salt made the aggregation of p(AM/AMC12S/GTE-10) molecules more compact, and the spatial network structure formed was more stable. p(AM/AMC12S/GTE-10) polymer aqueous solution with a mass fraction of 0.7% showed good temperature resistance at 140 ℃. After shearing at 120 ℃ and 170 s-1 for 1 h, 0.7% polymer solutions were prepared in 20,000 mg/L NaCl and CaCl2 aqueous solutions with viscosities of 64.7 and 54.2 mPa·s, respectively. The thixotropic tests show that the polymer has good shear recovery performance. The results of viscoelastic test show that the energy storage modulus (G ") is higher than the loss modulus (G "), and the metal ion and phenoxyethylene group have complex reaction, which enhances the intermolecular force, and the formed spatial structure is more stable and difficult to be destroyed, and the viscoelastic is higher.

Abstract:Aiming at those problems that plugging water agents are lower bonding strength, easily cracked in the progress of water plugging and difficultly degraded when agent has been cured, this paper offers a way to prepare a degradable and high-strength resin water plugging agent by using vegetable oil residue with epoxidation modification and methylhexahydrophthalic anhydride. Based on a combination of microstructure characterization, laboratory test and theoretical analysis, this paper evaluates thermal stability, compressive strength and water plugging performance of VOR, respectively, as well as explains curing mechanism and degradation mechanism of VOR. The rheological properties, stability, mechanical properties, plugging performance, curing mechanism and degradation mechanism of the plugging agent were investigated by means of theoretical analysis, microstructure characterization and indoor experimental evaluation. The results showed that the preparation mechanism of VOR gel was polyester crosslinking polymerization.The plugging agent has good injection performance and controllable curing time. The compressive strength of the plugging agent is more than 40 MPa, the thermal degradation temperature is 257.87 °C, and the mass retention rate of the plugging agent is more than 93 % under the condition of high temperature and high salinity ( curing temperature is 100 °C, salinity ≥ 8 × 10_⁴ mg / L ) for 90 days. The plugging agent has excellent stability. The distribution of spherical particles of plugging agent molecules endows the plugging agent with high strength and high adhesion characteristics, which makes the plugging agent have excellent plugging performance. When the temperature is 100 °C, the breakthrough pressure of water flooding is greater than 20 MPa. At 80 ~ 140 °C, the VOR gel can be completely degraded within 270 h, and the higher the reaction temperature, the faster the degradation rate. The infrared spectrum confirmed that the degradation mechanism of the plugging agent was the decomposition of the ester bond in the cross-linked structure. The development of this plugging agent not only realizes the resource utilization of plant residue, but also meets the needs of high-strength plugging agent for plugging and pressure integration, casing leakage treatment, horizontal well pipe external channeling and other operations.

Abstract:A series of aromatic esterification products were synthesized from aryl alcohol and phenol with aliphatic anhydride using acidic HBeta zeolite as a catalyst under clean and mild reaction conditions. The optimal reaction conditions were determined as follows: HBeta zeolite catalyst (10 mg), 4-methylbenzyl alcohol (Ⅰa, 0.5 mmol), acetic anhydride (Ⅱa, 0.5 mmol), cyclohexane (1.5 mL), reaction at room temperature in an inert atmosphere for 1 h, the yields of 4-methylbenzyl acetate (Ⅲaa) reached over 99%. Then, 32 kinds of aromatic esterification products were synthesized from a wide range of substrates. The catalysts were characterized by XRD, N2-adsorption, NH3-TPD, and Py-IR, the structure parameters and acidity of the catalysts were determined. It was found that the esterification rate of aryl alcohol and phenol gradually decreased from >99% to 57%, with the concentration of HBeta's strong Br?nsted acid sites (SBAS) decreased, indicating that the SBAS of the catalysts are the active sites for converting aryl alcohols and phenols into carbon cations. No significant activity loss was observed with product yield still up to 98% after being recycled 5 times. Finally, based on the characterization and experimental results, it is suggested that aryl alcohols and phenols first undergoed transformation into the corresponding carbocation intermediates on the strong Br?nsted acid sites (SBAS) of HBeta zeolite, which is then followed by a nucleophilic addition reaction with electron-rich oxygen in acid anhydride to yield the target products.

Abstract:Various 1-substituted thiophenol isochromans were obtained via 1-carboxyethyl-3-methylimidazolium chloride ([COOH-EtMIm][Cl])-catalyzed dehydrogenation coupling reaction between thiophenols and isochroman. After screening the reaction conditions, the optimal conditions were provided as follows: p-toluenethiol 0.5 mmol, isochroman 1.0 mmol, [COOH-EtMIm][Cl] 0.5 mmol, O2 pressure 0.1 MPa, reaction temperature 120 ℃, and reaction time 12 h. With the standard reaction conditions in hind, the catalyst can be reused for 4 times, the gram-scale synthesis of 1-thiophenol isochroman was accomplished, and 12 1-substituted thiophenol isochromans with yields ranging from 52% to 96% were obtained. In addition, the reaction mechanism was proposed: Anion and cation ions of [COOH-EtMIm][Cl] separately activated thiophenol and isochroman, following to be oxidated by O2 and dehydrogenation to form 1- thiophenol isochroman.