Kinetics study of the N-formylation of aniline with DMF catalyzed by temperature-controlled Brùnsted ionic liquids

A series of SO_(3)-functional Br?nsted acidic ionic liquids(SBAILs)were prepared to catalyze the Nformylation of aniline with DMF.The reaction conditions such as ionic liquid type,reaction temperature.catalyst loading and molar ratio of reactants were investigated.To the best of our knowledge,kinetic model for the N-formylation of aniline with DMF using SBAIL was firstly built and simulated.The studies on the reaction order of the reaction were evaluated by initial concentration method,and the kinetic parameters such as reaction rate constant and activation energy were proposed and used to explain the catalytic activities of the SBAILs catalysts.Accordingly,the recycling experiments showed that the SBAIL[Bsmim][HSO_(4)]can be easily recovered and reused with stable activity.Further,the temperature-controlled study emphasized that the ionic liquid was easy to be separated and environmentally friendly.

Temperature-controlled DCP Fluorescent Probe Based on Hydrogel-immobilized Quantum Dots Composite

A composite was created by incorporating the quantum dot-enhanced SiO_(2)nanoparticles within this hydrogel.Based on this composite,a temperature-controlled fluorescent probe for DCP was developed.A meticulous examination of this probe revealed its attributes and factors affecting its performance.By using temperature modulation,the probe was adept at detecting DCP concentrations ranging between 1.0×10^(-6)and 9.0×10^(-6)mol/L.Such a probe offers remarkable selectivity,repeatability,and robust stability,so that the detection of DCP can be carried out at different temperatures,and a fast,reliable,sensitive and low-cost intelligent detection method is realized.

Temperature-controlled fabrication of hydrophilic manganese oxide microspheres as high-performance electrode materials for supercapacitors

The supercapacitive properties of manganese oxides(MnO_(x))are strongly affected by their crystal structure.Nevertheless,the relationship between the crystal structure and supercapacitive performance of Mn O_(x)is elusive.Herein,a temperature-controlled fabrication method was developed to achieve MnO_(2),Mn_(3)O_(4),MnO and Mn_(2)O_(3)microspheres with various crystal structure as electrode materials tunable for supercapacitors.The detailed material and electrochemical characterizations revealed the structureactivity relationship of Mn O_(x)microspheres by systematically investigating the effect of valence state,specific surface area,conductivity and morphology on supercapacitive performance.Among these MnO_(x)materials,nanoneedle-like Mn O_(2)delivered a relatively high specific capacitance of 274.1 F/g at 1 A/g due to a high Mn valence state of+4,a large specific surface area of 113.4 m^(2)/g and a desirable electronic conductivity of 1.73×10^(-5)S/cm.Furthermore,MnO_(2)presented a remarkable cycle stability with 115%capacitance retention after 10,000 cycles owing to the enhancement of wettability.This work not only provides a facile strategy to modulate MnO_(x)crystal structure,but also offers a deep understanding of structure-dependent supercapacitive performance of MnO_(x).

Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan,triclocarban and methyl-triclosan in aqueous samples

As extraction solvents,ionic liquids have green characteristics.In this study,an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS),triclocarban (TCC) and methyl-triclosan (M-TCS) in water samples.Significant parameters that may affect extraction efficiencies were examined and optimized,including the types and amount of ionic liquids,volume of the diluent,heating temperature,cooling time,salt effect and pH value.Under the optimum conditions,linearity of the method was observed in the ranges of 0.0100-100 μgL-1 for TCS and M-TCS,and 0.00500-50.0 μgL-1 for TCC with correlation coefficients (r2) > 0.9903.The limits of detection (LODs) ranged from 1.15 to 5.33 ngL-1.TCS in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μgL-1,respectively.The spiked recoveries of the three target compounds in reclaimed water,irrigating water,waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%,61.6%-87.8%,58.9%-74.9% and 64.9%-92.4%,respectively.Compared with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS,TCC and M-TCS,this method is not only more environmentally friendly but also more sensitive.

Study on Thermal Insulation Performance of Cross-Laminated Bamboo Wall

In recent years,bamboo,as a green building material,has attracted more and more attention worldwide.Inspired by the investigation of cross-laminated timber in structural systems,a new engineered cross-laminated bamboo(CLB)consisting of the cross lamination of bamboo scrimber plates is proposed in this paper.To evaluate its potential in structural applications,the thermal insulation performances of the CLB walls and CLB walls with the EPS foam plate were studied and evaluated by the temperature-controlled box-heat flow meter method.Test results indicated that the thermal insulation performance improved with the increase of thickness,but different wall configurations had little effect on the thermal insulation performance under the same thickness of the CLB wall.The thermal insulation performance of EPS-CLB composite wall was much better than that of CLB wall.In addition,a relatively acceptable accuracy of the theoretical calculations was proved.Finally,the influence of different locations of the EPS foam plate on heat transfer coefficient can be neglected as it was studied based on the validated numerical models.

Temperature-controlled mode selection of Er-doped random fiber laser with disordered Bragg gratings

In this paper, we proposed a way to realize an Er-doped random fiber laser(RFL) with a disordered fiber Bragg grating(FBG) array, as well as to control the lasing mode of the RFL by heating specific locations of the disordered FBG array. The disordered FBG array performs as both the gain medium and random distributed reflectors, which together with a tunable point reflector form the RFL. Coherent multi-mode random lasing is obtained with a threshold of between 7.5 and 10 mW and a power efficiency between 23% and 27% when the reflectivity of the point reflector changes from 4% to 50%. To control the lasing mode of random emission, a specific point of the disordered FBG array is heated so as to shift the wavelength of the FBG(s) at this point away from the other FBGs.Thus, different resonance cavities are formed, and the lasing mode can be controlled by changing the location of the heating point.

Combination of ionic liquid dispersive liquid-phase microextraction and high performance liquid chromatography for the determination of triazine herbicides in water samples

A temperature-controlled ionic liquid dispersive liquid-phase microextraction in combination with high performance liquid chromatography was developed for the enrichment and determination of triazine herbicides such as cyanazine,simazine,and atrazine in water samples.1-Octyl-3-methylimidazolium hexafluorophosphate（[C8MIM][PF6]） was selected as the extraction solvent.Several experimental parameters were optimized.Under the optimal conditions,the linear range for cyanazine was in the concentration range of 0.5–80 mg/L and the linear range for simazine and atrazine was in the range of1.0–100 mg/L.The limit of detection（LOD,S/N = 3） was in the ranges of 0.05–0.06 mg/L,and the intra day and inter day precision（RSDs,n = 6） was in the ranges of 3.2%–6.6% and 4.8%–8.9%,respectively.Four real water samples were analyzed with the developed method,and the experimental results showed that the spiked recoveries were satisfactory.All these exhibited that the developed method was a valuable tool for monitoring such pollutants.

Temperature-driven braking of γ-cyclodextrin-curcubit[6]urilcowheeled [4]rotaxanes

Several cyclodextrin-cucurbit[6]uril-cowheeled [4]rotaxanes were synthesized through the cucurbit[6]uril-templated azide-alkyne 1,3-dipolar cycloaddition. The intramolecular interaction between the aromatic axle and the capping groups of cyclodextrin moieties was investigated by UV-vis, fluorescence,circular dichroism and NMR spectroscopic studies. The rotational kinetic of the wheel around the axle can be manipulated by adjusting the temperature. The capping group apparently slowed down the rotation of the wheel, playing a role of the brake, and lowering the temperature can stop the rotation of the wheel on the NMR timescale.

Metabolic engineering of Escherichia coli for efficient ectoine production

Ectoine is a high-value stabilizer and protective agent with various applications in enzyme industry,cosmetics,and biomedi-cine.In this study,rational engineering strategies have been implemented in Escherichia coli to efficiently produce ectoine.First,the synthetic pathway of ectoine was constructed in E.coli MG1655 by introducing an artificial thermal switch system harboring the ectABC cluster from Halomonas elongate,and the resulting strain produced 1.95 g/L ectoine.Second,crr encoding the glucose-specific enzyme II domain A of phosphotransferase system and iclR encoding the glyoxylate shunt transcriptional repressor were deleted in E.coli for enhancing the oxaloacetate supply,leading to the increasement of the ectoine titer to 9.09 g/L.Third,thrA encoding the bifunctional aspartokinase/homoserine dehydrogenase was removed from the genome to weaken the competitive pathway;simultaneously,an endogenous feedback-resistant lysC was overexpressed to complement the enzymatic activity deficiency of the aspartate kinase,leading to 30.36%increase of ectoine titer.Next,the expression of phosphoenolpyruvate carboxylase was modulated with varying gradient strength promoters to accelerate the biosynthesis efficiency of ectoine.Finally,aspDH encoding aspartate dehydrogenase from Pseudomonas aeruginosa PAO1 was overexpressed to further improve the biosynthesis of ectoine.The final strain MWZ003/pFT28-ectABC-EclysC^(*)-aspDH-ppc3 produced 30.37 g/L ectoine after 36-h fed-batch fermentation with a yield of 0.132 g/g glucose and a productivity of 0.844 g/(L h).