脂酶催化及应用于光活性有机物的合成

脂肪酶是水解酶,它能在有机溶剂体系中,对广泛的底物催化不对称水解或不对称酰化,且容易得到,使用方便。近年来已被人们广泛地接受成为一种合成光学活性有机化合物的方法。本文讨论了脂肪酶的一般特性,并介绍了脂肪酶在制备光学活性天然产物以及医药农药等方面的应用。

Recent advances in VOCs and CO removal via photothermal synergistic catalysis

Currently,air pollution is being exacerbated by rapid social,economic,and industrial development.Major air pollutants include volatile organic compounds(VOCs)and CO.Photocatalytic and thermocatalytic technology can be used to convert VOCs and CO into harmless gases effectively.Recently,photothermal synergistic catalysis has aroused much attention because of its higher performance than those of individual photocatalytic and thermocatalytic processes.There have been many reviews on separate photocatalysts and thermocatalysts for the treatment of VOCs and CO,but few reviews have focused on photothermal synergistic catalysis.In this minireview,we concentrate on recent progress into photothermal synergistic catalysis for the efficient removal of VOCs and CO.The treatment of typical VOCs(such as benzene,toluene,ethanol,formaldehyde,acetone,propylene,and propane)and CO are summarized and analyzed.Furthermore,we discuss the use of conventional reactor technology,such as fixed‐bed quartz reactors,for VOCs and CO removal.We also discuss the mechanism of the photothermal synergistic catalytic removal of VOCs and CO.Finally,we present perspectives for the photothermal synergistic catalytic removal of VOCs and CO.

Preparation and Spectroscopic Study of Different Stoichiometric Solid Supramolecular Inclusion Complexes of β-Cyclodextrin with Short Chain Aliphatic Amines

The solid Supramolecular complexes of β-cyclodextrin （β-CD） with ethylenediamine 1, diethylenetriamine 2 and triethylamine 3 were obtained and characterized using elemental analysis, powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and ^1H nuclear magnetic resonance spectroscopy. Based on the results of elemental analysis and ^1H NMR, the guest-host stoichiometries of the three solid complexes were determined to be 5：2 for 1-β-CD, hl for 2-β-CD, and 1：3 for 3-β-CD. The yields were relative to the molar volume ratio of guest to β-CD cavity, and increased in the order： 1-β-CD〈2-3-CD〈3-β-CD. X-ray diffraction patterns of the inclusion complexes gave very good exhibitions not only in location of diffraction peaks but also in shape and diffraction intensity of the peaks due to the intermolecular complexations between β-CD and the guests. The formation of host-guest inclusion complexes exhibited obviously enhanced phase change temperatures of the complexed guests such as 1 and 3. The H-5 protons located at the narrower rim inside the CD cavity experienced a higher shift upon inclusion while all other protons experienced lower shifts.

Insight into catalytic properties of Co3O4-CeO2 binary oxides for propane total oxidation

A series of Co3O4-CeO2 binary oxides with various Co/(Ce+Co)molar ratios were synthesized using a citric acid method,and their catalytic properties toward the total oxidation of propane were examined.The activities of the catalysts decrease in the order CoCeOx-70>CoCeOx-90>Co3O4>CoCeOx-50>CoCeOx-20>CeO2.CoCeOx-70(Co/(Ce+Co)=70% molar ratio)exhibits the highest catalytic activity toward the total oxidation of propane,of which the T90 is 310℃(GHSV=120000 mL h^-1 g^-1],which is 25℃ lower than that of pure Co3 O4.The enhancement of the catalytic performance of CoCeOx-70 is attributed to the strong interaction between CeO2 and Co3O4,the improvement of the low-temperature reducibility,and the increase in the number of active oxygen species.In-situ DRIFTS and reaction kinetics measurement reveal that Ce addition does not change the reaction mechanism,but promotes the adsorption and activation of propane on the catalyst surface.The addition of water vapor and CO2 in reactant gas has a negative effect on the propane conversion,and the catalyst is more sensitive to water vapor than to CO2.In addition,CoCeOx-70 exhibits excellent stability and reusability in water vapor and CO2 atmosphere.

Synthesis and Characterization of a New Bifunctional Dye Containing Spirobenzopyran and Cinnamoyl Moiety

A novel bifunctional dye containing spirobenzopyran and cinnamoyl moiety has been prepared and its photochromic behavior following irradiation at different wavelengths of monochrome UV light was investigated. The colourless bifunctional dye in film or solution exhibits unusual photochromism through structural and geometrical transformation from spirobenzopyran to merocyanine accompanying with photocrosslinking reaction in cinnamoyl moieties. Two kinds of photochemical reaction were achieved by irradiation at the different wavelengths of monochrome UV light (275 nm, 365 nm) selectively. The photochromic process of the bifunctional dye was discussed and the dynamic behaviors of the decolorization process were investigated.

A new germacranolide from Carpesium cernuum

As a part of our interest in biologically active germacranolides from the genus Carpesium （Compositae）, we have investigated the constituents of Carpesium cernuum. This paper reports the isolation and structural elucidation of a new germacranolide, cernolide A （Compound 1）, from the herb. The structure of Compound 1 was determined as 2α,3β-dihydroxy-9-angeloxygermacra-4-en-6,12-olide on the basis of spectral evidence. The skeleton of Compound 1 was elucidation by IR, MS, ^1H and ^13C NMR, COSY, HMQC and HMBC experiments. The stereochemistry of Compound 1 was deduced by ROESY spectral data. Finally, the procedures of extraction and isolation were described in detail.

Pc-Si and c-Si Cell Studies at Transient and Steady State Conditions in Various Illumination Levels

A set of experiments was designed to study the power performance of a c-Si and a pc-Si cell when exposed to various levels of high illumination. The light concentration ratio, C, ranges from C 〈 1, up to C ≈ 26. An experimental set up was built for the purposes of this project. PV cell modeling is outlined in this paper for isc, Voc and the PV cell temperature, Tc, which predicts those quantities. There the behaviour of the two PV-cells at both transient out steady state conditions is studied. Predicted values are compared against measured ones. A comparison of the experimental values against the theoretically predicted ones is performed for the range C 〈 1 to C ≈ 26. Power recovery is tried through heat removal from both sides of the PV-cells by air forced flow. Experiments show recovery whose degree is close to 100% for low C values. On the other hand, as C grows higher, P~ starts decreasing too. PV cell temperatures reached up to 136 ℃ for C = 25. This is a challenge as reduction of temperature delivers a good amount of heat, in the cogeneration effect, while it has a positive impact to power recovery of the PV cell.

Tribological Performance of Two Potential Environmentally Friendly Ashless Vegetable Oil Additives

Two potential novel environmentally friendly ashless vegetable oil additives, 2-mercaptobenzothiazole derivatives, di-n-dodecyl-[2-（2-benzothiazolyl）thio]ethylborane （LBN） and di-n-dodecylthio-[2-（2-benzothiazolyl） thio]ethylborane （LBNS）, were synthesized and their tribological performance as additives in rapeseed oil （RSO） was evaluated using a four-ball wear tester. Their anti-corrosive properties and thermal stability were also examined. The worn surface of the steel ball was analyzed by means of scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS）. The results showed that 2-mercaptobenzothiazole derivatives exhibited excellent anti-corrosive property and high thermal stability. Moreover, they both had good load-carrying capacities and anti-wear and friction-reducing properties. The PR values of samples decreased in the following order： LBNS〉 LBN〉RSO. The results of XPS examination illustrated that the excellent tribological behavior of the prepared compounds used as additives in RSO was attributed to the formation of a protective lubrication film on the worn surface, which consisted of an adsorption layer and a reaction layer containing Fe3O4, FeS, Fe2（SO4）3, FeB, and organic nitrogen-containing compounds.

Theoretical investigation of photoelectric properties of the four-coordinate organoboron compounds based on diketopyrrolopyrrole derivativ

In order to obtain high efficiency of organic light-emitting diodes and organic solar cells,a series of DPP-based four-coordinate organoboron compounds have been designed for photoelectric functional materials.The effects of electron-donating and-withdrawing substituent on the electronic and optical properties have been investigated by using density functional theory(DFT)and time-dependent DFT(TD-DFT)approaches systematically.It turned out that electron-donating and-withdrawing groups can tune effectively the frontier molecular orbital(FMO)energy level,energy gap,and absorption and fluorescence spectra.The introduction of electron-withdrawing groups for the parent molecule HBDPP(2,5-bis(diphenylboryl)-3,6-bis(pyridin-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione)favors the decrease for the FMO energy(E_(LUMO)and E_(HOMO)),HOMO-LUMO gaps(E_(g)),and the downhill energetic driving force(ΔEL-L),while the electron-donating groups can increase E_(LUMO),E_(HOMO),E_(g),andΔEL-L compared with that of HBDPP,respectively.The absorption and fluorescence spectra of the electron-withdrawing substituted derivatives exhibit bathochromic shifts,while the absorption and fluorescence spectra of the electrondonating substituted derivatives show hypsochromic shifts compared with the parent molecule HBDPP,respectively.Furthermore,the stronger the electron-withdrawing/donating ability of group is,the more significant the effect in the optoelectronic properties.

Construction of porous covalent organic polymer as photocatalysts for RhB degradation under visible light

In the present work, a novel porous, and chemically stable amine-based covalent organic polymer （POP-1） was designed and synthesized under solvothermal conditions. The porosity, crystallinity, chemical stability, electrochemical properties, and diffuse reflectance of POP-1 were investigated via N2 sorp- tion experiment, power X-ray diffraction, thermogravimetric analysis, cyclic voltammetry, and ultraviolet visible near infrared spectrometry, respectively. POP-I exhibits good chemical stability in both acidic and alkaline aqueous solutions, as well as in organic solvents. Undoped POP-1 can be directly used as a pho- tocatalyst for rhodamine B irradiation degradation under light-emitting diode and natural light. The Ea of POP-1 for RhB degradation is 82.37 kJ/mol. Furthermore, POP-1 can be reused as a catalyst in RhB degra- dation without degraded catalytic activity.

Secondary aerosol formation and oxidation capacity in photooxidation in the presence of Al_2O_3 seed particles and SO_2

To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were conducted in smog chambers in the absence or presence of Al2O3 seed particles. Various concentrations of NOx and volatile organic compounds(VOCs) were designed to simulate secondary aerosol formation under different scenarios for NOx. Under "VOC-limited" conditions, the increasing NOx concentration suppressed secondary aerosol formation, while the increasing toluene concentration not only contributed to the increase in secondary aerosol formation, but also led to the elevated oxidation degree for the organic aerosol. Sulfate formation was suppressed with the increasing NOx due to a decreased oxidation capacity of the photooxidation system. Secondary organic aerosol(SOA) formation also decreased with the presence of high concentration of NOx, because organo-peroxy radicals(RO2) react with NOx instead of with peroxy radicals(RO2 or HO2), resulting in the formation of volatile organic products. The increasing concentration of NOx enhanced the formation of sulfate, nitrate and SOA under "NOx-limited" conditions, in which the heterogeneous reactions played an important role. In the presence of Al2O3 seed particles, a synergetic promoting effect of mineral dust and NOx on secondary aerosol formation in heterogeneous reactions was observed in the photooxidation. This synergetic effect strengthened the positive relationship between NOx and secondary aerosol formation under "NOx-limited" conditions but weakened or even overturned the negative relationship between NOx and secondary aerosol formation under "VOC-limited" conditions. Sensitivity of secondary aerosol formation to NOx seemed different in homogeneous and heterogeneous reactions, and should be both taken into account in the sensitivity study. The sensitivity of secondary aerosol formation to NOx was further investigated under "winter-like" and NH3-rich conditions. No obvious difference for the sensitivity of secondary aerosol formation except nitrate to NOx was observed.

Effect of aluminium dust on secondary organic aerosol formation in m-xylene/NO_x photo-oxidation

As an important anthropogenic volatile organic compound(VOC), m-xylene has attracted numerous attentions due to its potential in secondary organic aerosol(SOA) formation. In this study, effects of aluminium dust seeds(boehmite and alumina) on SOA yield and aerosol size in m-xylene/NOx photo-oxidation were investigated in a 2 m3 smog chamber at 30°C and 50% relative humidity. Compared to the seed-free system, the presence of aluminium seeds resulted in an increase in the SOA yield, and also enhanced the O3 concentration in the chamber. The photolysis of O3 is a major source of OH radical, which is the most important oxidant of m-xylene. The increase in O3 concentration could result in the generation of more OH radicals, and finally contribute to the SOA formation. Seed particles influence the SOA size mainly by acting as condensation nuclei. Semi-volatile organic compounds(SVOCs) were condensed onto these nuclei, resulting in the increase in SOA size. However, when aluminium seeds with high concentrations were introduced into the system, SVOCs that had been condensed onto each particle were dispersed by these seeds, leading to the reduction in aerosol size.

Performance of polymer/CdS organic-inorganic hybrid LEDs

Organic-inorganic hybrid light emitting diodes(LEDs) were fabricated by incorporating cadmium sulphide(Cd S) nanoparticles in hole transporting layer and light emitting materials of a polymer LED. The Cd S nanoparticles with size of 10 nm were synthesized by precipitation technique. The LEDs incorporated with the Cd S nanoparticles show a reduction in turn on voltage and luminance. When the nanoparticles are incorporated in a suitable fluorene based light emitting polymer, the luminance is increased along with the decrease of turn on voltage.