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1.
《Journal of Sulfur Chemistry》2013,34(2):223-229
Herein, the chemistry of 2-aminothiophenol has been utilized in the synthesis of several interesting products such as oxidation and reaction with π-deficient compounds. On oxidizing 2-aminothiophenol by sodium hypochlorite furnishes 2-[(2-aminophenyl)-dithio]aniline. Treatment of the obtained product with acetyl chloride affords N-(2-[2-(acetylamino)-phenyl-disulphanyl)-phenyl]acetamide. Reaction of the former acetamide with POCl3 yields 2-methyl-1,3-benzothiazole. Moreover, (3,4,8,9)-dibenzo-2,7-dithia-5,10-diaza4 4 4propellane is formed on reacting the target 2-aminothiophenol with cyclohexane-1,2-dione, whereas its reactions with electron π-acceptors such as 2,3-dichloro-1,4-naphthoquinone (DCHNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetra-cyanoethylene (TCNE), and 1-(dicyanomethylen)acenaphthen-2-one yield various heterocycles. 相似文献
2.
《Journal of Sulfur Chemistry》2013,34(5):549-558
Synthesis of a new class of 1, 3-thiazolidine nucleoside analogs is described. Reaction of 2-amino-2-deoxy-D-glucopyranose hydrochloride 2 with carbon disulfide yielded 5-hydroxy-4-(D-arabino-1, 2, 3, 4-tetrahydroxybutyl)-thiazolidin-2-thione 3, which on acetylation yielded 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxy-butyl)-thiazolidin-2-thione 4. The acetylated sugar 4 reacted with hydrazonoyl chlorides 1a–f, affording the 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxybutyl)-spiro-1 3thiazolidine-2,2′ -1 3 4thiadiazole derivatives 8a–f. The antibacterial activity of the novel 1, 3-thiazolidine-2,2′ -spiro- 1 3 4thiadiazole nucleoside analogs is highlighted. All compounds with free NH group in the thiazolidine series 8a–f showed significant biological activity against all the standard strains. 相似文献
3.
Atmospheric aerosols are one of the least understood components of the climate system and incur adverse health effects on susceptible populations. Organic aerosols can make up as much as 80% of atmospheric aerosols (Lim and Turpin 2002), and so its quantification and characterization plays an important role in reducing our uncertainty with regards to aerosol impacts on health and climate. As the number of organic molecules in the atmosphere are diverse in number (Hamilton et al. 2004), we advance a functional group representation of organic molecules as measured by Fourier transform infrared spectroscopy (FTIR) to characterize the chemical composition of particle samples. This study describes and evaluates the algorithm introduced by Russell et al. (2009) for apportionment and quantification of oxygenated (carbonyl and hydroxyl) functional groups from infrared absorption spectra. Molar absorptivities for carbonyl and hydroxyl bonds in carboxylic groups are obtained for several dicarboxylic compounds, and applied to a multifunctional compound and mixture to demonstrate the applicability of this method for more complex samples. Furthermore, functional group abundances of two aldehydic compounds, 2-deoxy-d-ribose and glyceraldehyde, atomized from aqueous solution are in quantitative agreement with number of bonds predicted after transformation of these compounds into diols. The procedure for spectra interpretation and quantitative analysis is described through the context of an algorithm in which contributions of background and analyte absorption to the infrared spectrum are apportioned by the superposition of lineshapes constrained by laboratory measurements. Copyright 2013 American Association for Aerosol Research 相似文献
4.
An aerosol dynamics model for dry deposition process is developed based on the moment method. Since it is hard to fully apply the moment method to the widely used dry deposition velocity expressions based on the resistance theory, the dry deposition velocity expression by Raupach et al. (2001) is used. Detailed deposition mechanisms such as Brownian diffusion, gravitational settling, and impaction are considered in the expression. To verify the validity of the derived dynamic equation, aerosol dynamics for the dry deposition process is estimated with the expressions of Raupach et al. (2001), of Wesely (1989) modified for particles (Seinfeld and Pandis 1998), in CMAQ, and with constant value used in RAINS-ASIA. Those expressions give different dynamics. Generally, the result for this study is between the result of modified Wesely's expression and CMAQ. When using the modified Wesely's expression with the number of sections being equal or smaller than 10, the resultant size distribution does not give the peak shape accurately. 相似文献
5.
Daryl L. Roberts 《Aerosol science and technology》2013,47(11):1119-1129
We describe a general theory of multi-nozzle cascade impactor stages and show how testers of inhaled drug products, such as metered-dose or dry-powder inhalers, can decide, solely from the stage nozzle dimensions, whether any used impactor is satisfactorily operating within its expected aerodynamic performance range. We first account for the realistic shape of particle collection efficiency curves and show that the effective diameter, described by Roberts and Romay (2005), is sufficiently accurate as the primary indication of the aerodynamic performance.To ensure that a used impactor is performing in the same aerodynamic range allowed for new impactors, one must also satisfy the other, more secondary factors of cascade impaction aerodynamics, most notably the distance to the collection surface relative to the nozzle diameter. We show what this constraint means in practice for used Next Generation Impactors (NGIs; Marple et al. 2003a, b; 2004), and show that partially occluded nozzles are the most likely nozzles to fail this test.Applying this principle that used impactors should perform in the same aerodynamic range as new impactors, we derive constraints on the nozzle diameters of any used NGI (Table 6, main text). We can partially apply this principle to other common impactors used for inhaler testing, such as the Andersen and the Marple-Miller, but are hindered by the absence of a published acceptable range for the distance to the impaction collection surface and by the limited published information on the shape of their stage collection efficiency curves. 相似文献
6.
A general methodology is presented that enables rigorous estimation of the total collection efficiency and the size distribution of particles penetrating dust control systems. This methodology assumes lognormal inlet particle-size distributions and can be used with fractional efficiency formulations that predict, under such conditions, lognormal outlet particle-size distributions. Multimodal inlet particle distributions can be accommodated additively. This methodology is applied to Electrostatic Precipitator Systems (ESPs), with the Nobrega et al. (2004) model selected for predicting their fractional efficiencies. For ease of use, a graphical solution has been developed for the Nobrega et al. fractional efficiency relations, but its availability is not a prerequisite for the application of the general methodology. For the latter, the fractional efficiencies corresponding to three particle diameters need to be estimated and this can be done either graphically or numerically using the model of Nobrega et al. or any other fractional efficiency formulation of interest. Fine particles emerge as the most important pollutant worldwide in terms of human health, creating thus the need for credible particle size-specific inventories. In line with the above, a generic and rigorous method, capable of producing size-specific emission estimates from uncontrolled and controlled sources, has been developed (Economopoulou and Economopoulos 2001). For controlled sources, this method relies on the development of easy to use models that predict the total efficiency and the lognormal size distribution of particles penetrating the control systems used. Such models have already been developed for dry cyclone separators (Economopoulou and Economopoulos 2002a, 2002b) and venturi scrubbers (Economopoulou and Harrison 2007a, 2007b). The present methodology extends the use of the inventory methodology to ESP-controlled sources and, in addition, it provides a generalized basis for covering other types of control systems with any fractional efficiency formulation considered appropriate. 相似文献
7.
This paper describes the usefulness of one-dimensional diffusion-ordered NMR spectroscopy (1D-DOSY) in investigating dynamics and interactions of molecules in solution as well as in analyzing the structure of molecules. We synthesized the three imines, N-benzylidene-4-methylbenzene-Sulfonamide (1), N-(4-chloro-benzylidene)4-methyl-benzene-sulfonamide (2), and N- (4-methoxybenzylidene)-4-methyl-benzene sulfonamide (3), and acetophenone (4) and its three derivatives, 4-chloroacetophenone (5), 4-nitro-acetophenone (6), and 4-methoxyaceto -phenone (7). 1D-DOSY was applied to a mixture of compounds (1), (2), and (3) and to a mixture of compounds (4), (5), (6), and (7). Although 1 H NMR chemical shifts of the molecules in the mixtures resembled one another in the surrounding, we could distinguish signals of the individual molecules in each mixture on the basis of the NMR data and the values of the diffusion coefficient. Also, we could found the correlation of the measured diffusion coefficients and the calculated molecular volumes. 相似文献
8.
Ronald G. Harvey Qing Dai Chongzhao Ran Keunpoong Lim Ian Blair Trevor M. Penning 《Polycyclic Aromatic Compounds》2013,33(5):371-391
Syntheses are reported for: (1) adducts of the quinone metabolites of benzo[a]pyrene (BPQ) and benz[a]anthracene (BAQ) with 2′-deoxyadenosine and 2′-deoxyguanosine; (2) 15 N-labelled analogs of these adducts (four or five nitrogen atoms 15 N-labelled); (3) depurinated adducts of BPQ and BAQ with adenine or guanine covalently linked to the N7 or N9 positions of the purine bases; (4) 13 C-labelled derivatives of benzo[a]pyrene, BPQ, benzo[a]pyrene trans-7,8-dihydrodiol, and the benzo[a]pyrene anti-diol epoxide (with 13 C-atoms at the 5- and 11-positions); and (5) depurinated adducts formed by reactions of the benzo[a]pyrene radical-cation at the C 8 -, N 7 -, and N 9 -positions of adenine and guanine. 相似文献
9.
10.
Abstract We discuss the performance of “closed-end” fluctuation tests, used to detect changes in the structural stability of a model, in the case where the time horizon is large and the observations do not possess high enough moments. It is demonstrated via a simulation study that, in the latter case, the choice of the boundary function should take into account the number of moments existing; otherwise the actual size of the test may exceed the nominal level. We suggest an alternative “open-end” fluctuation procedure and study its asymptotic behavior. It turns out that if an improper boundary function is chosen, then the null hypothesis may be rejected even if it is true. This means that an appropriate choice of the boundary function requires some prior information about the tail heaviness of the observations. This is different from the cumulative sum-based monitoring schemes suggested by Chu et al. (1996) and further studied by Horváth et al. (2004). 相似文献
11.
《Journal of Sulfur Chemistry》2013,34(4-5):381-391
Pyridine-2(1H)-thione 1 reacted with phenyl isothiocyanate to give pyrido[2,3-d]pyrimidine derivative 3. Compound 3 reacted with halogen containing compounds 4a–d and methyl iodide in dimethylformamide/potassium hydroxide solution at room temperature to give 2,7-bisalkylthiopyrido[2,3-b]pyrimidine derivatives 5a–d and 9, respectively. Compounds 5a–d could be cyclized into thienopyrido[2,3-d]pyrimidine derivatives 6a–d by boiling with ethanolic potassium hydroxide solution. Compound 6a reacted with acetic anhydride or formic acid and gave the corresponding pyrimido[4″,5″:4′,5′]thieno[3′,2′:5,6]pyrido[2,3-d]pyrimidine derivatives 8a,b. Compound 9 reacted with hydrazine hydrate to yield pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivative 11 which could be reacted with nitrous acid and dimethylformamide-dimethylacetal (DMF-DMA) and gave the final isolable products corresponding to the pyrazolo[4′,3′:5,6]pyrido[2,3-d]tetrazolo-[5,1-b]pyrimidine and pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]1 2 4triazolo-[4,3-b] pyrimidine derivatives 13 and 17, respectively. Compound 11 also reacted with some β-dicarbonyl compounds such as acetylacetone (18) and ethyl acetoacetate (20) to yield the corresponding pyrimido[1″,2″:1′,5′]pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine derivatives 19 and 21, respectively. Finally, compound 11 reacted with chloroacetyl chloride (22) to give the corresponding imidazo[1″′,2″′:1″,5″]pyrazolo[4″,3″:5′,6′]pyrido[3′,2′:5,6]pyrimido[2,1-c]1 2 4triazine derivative 23. 相似文献
12.
Over the past two decades, significant efforts have been expended to identify the photochemical decomposition products of the OH radical reactions of various polycyclic aromatic compounds (PAC), such as naphthalene, methylnaphthalenes, acenaphthene and phenanthrene (1, 2, 3, 4, 5, 6, 7). Although these parent PAC are predominantly found in the gas phase, many of their oxidation products have been found largely in the particle phase (4, 7, 8). These products include diones, hydroxy-, and nitrated products as well as many products resulting from ring-opening steps. It is, or should be, the goal of every laboratory study on atmospheric processes to apply the laboratory results to real world samples. To this end, we have obtained particulate matter air samples, as well as some smog episode samples, from Seoul Korea and have searched for the known decomposition products of the above mentioned PAC. To eliminate the use of chlorinated solvents used in the extraction and analysis of particulate matter samples, we have been utilizing the direct thermal desorption of small (4 mm diameter) punches of filters followed by Multidimensional Gas Chromatography-Time of Flight Mass Spectrometry (TD-GCxGC-TOFMS) for the analysis of the desorbed compounds. So far, we have detected 14 of the known decomposition products of naphthalene, acenaphthene and phenanthrene in the Seoul pollution episode samples. These include: 1-hydroxynaphthalene, (E) 2-formylcinnamaldehyde, phthalic anhydride, phthalide, 1,2-naphthalic anhydride, 9-hydroxyphenanthrene and dibenzopyrone. 相似文献
13.
Matt Frain David P. Schmidt Yong-Le Pan Richard K. Chang 《Aerosol science and technology》2013,47(3):218-225
Pulsed airflow cued by the fluorescence spectrum of a particular aerosol can be used to distinguish and deflect particles of biological origin out of an aerosol stream, permitting concentration of these particles for subsequent analysis (Pan et al. 2004). However, these high velocity pulses of air have an inherent tendency to scatter particles, confounding efforts to concentrate these deflected particles for analysis. The ability to concentrate large numbers of biological particles into a small area on a collection substrate is particularly important for more species-specific techniques such as Raman and FTIR (Fourier Transform Infra-Red) spectroscopy, which require long integration times due to their weak signal strength. In the present work, a simple method is developed for deflecting and localizing particles after classification by a pulsed airflow. The concept is both modeled and experimentally tested. A specially designed funnel is used to localize the scattered particles onto an area of substrate as small as 1 mm in diameter. Computational fluid dynamics simulations were performed to investigate the interaction of the pulsed airflow with the deflected particles and the localizing funnel, in order to gain insight into design parameters and operating conditions that affect the efficiency of this technique. The results show that the combination of pulsed airflow with a localizing funnel effectively deflects and localizes the concentrated bioaerosol onto a small area of substrate or an opening of a microfluidic cell. 相似文献
14.
Zhi Ning Katharine F. Moore Andrea Polidori Constantinos Sioutas 《Aerosol science and technology》2013,47(12):1098-1110
Recently a new compact aerosol concentration enrichment system was developed at the University of Southern California, specifically intended to provide particle-laden air at flow rates and pressures suitable for interfacing with on-line continuous aerosol instrumentation for chemical analysis such as mass spectrometers. The re-design and engineering of the miniature Versatile Aerosol Concentration Enrichment System (mVACES) and primarily laboratory-based validation of the individual components and overall system has been previously reported (Geller et al. 2005). From September to December 2005, a field performance validation study of the mVACES was conducted in Los Angeles, California at a mixed urban site influenced by both freeway traffic and construction. A variety of continuous and semi-continuous physical and chemical composition measurements were performed to assess the performance of the mVACES compared to accepted methods for validation. Near-ideal performance for aerosol concentration enhancement by the mVACES was observed for mass and number distribution with minimal evidence for distortion of the size distribution. Similarly, near-ideal concentration enhancement factors were observed for both inorganic and organic species suggesting that the mVACES works equally well across the range of externally mixed urban aerosol. The data suggest that aerosol concentration enhancements up to an ideal factor of 20 in a delivered flow on the order of 1.5 liters min–1 are readily achievable in an urban environment for the ambient conditions studied. 相似文献
15.
《分离科学与技术》2012,47(2):264-276
A group of nearly forty-eight (48) of surfactants based on ionic liquids (ILs) has been described. The physicochemical and interfacial behavior for several of these IL-based surfactants has been reported since 2004. This review attempts to summarize the important applications that IL-based surfactants have had in analytical chemistry and separation science. Thus, they have been successfully used as extractant systems as substitutes to conventional organic solvents in extraction schemes, or by modifying the chemical structure of conventional extractant sorbents. The analytical performance of these novel IL-based surfactants has been shown to be better than conventional solvents and even better than conventional cationic surfactants. IL-based surfactants have also been used as mobile phase and stationary phase modifiers in high-performance liquid chromatography (HPLC), as modifiers of the electrokinetic chromatographic (EKC) medium, or as the micellar component in capillary electrophoresis (CE). Thus, IL-based surfactant methods constitute a promising and developing area within separation science. 相似文献
16.
Christopher D. Cappa Daniel A. Lack James B. Burkholder A. R. Ravishankara 《Aerosol science and technology》2013,47(12):1022-1032
Light absorption by soot or nigrosin dye aerosol particles were measured in the laboratory using a particle soot absorption photometer (PSAP) and a photo-acoustic spectrometer (PAS) to assess the influence of non-absorbing organic aerosol (OA) on the PSAP measurements. For the PSAP, particle light absorption is measured after collection on a filter, whereas for the PAS light absorption is measured while the particles remain suspended in the gas phase. OA was generated from the reaction of α -pinene with ozone. It was observed that the presence of this OA in an external mixture of absorbing aerosol and OA can cause an increase in the light absorption measured by the PSAP, relative to that measured by the PAS, by more than a factor of two. This enhancement in the PSAP absorption was found to increase as the amount of OA increased relative to the absorbing compound. Additionally, experiments where absorbing aerosol was deposited on a PSAP filter prior to addition of OA demonstrated that the non-absorbing OA can actually appear as if it were absorbing, with measured single scattering albedo values as low as 0.92. These results indicate that filter-based measurement techniques may significantly overestimate light absorption by aerosols in the atmosphere under conditions where the organic loading is large, with consequent implications for understanding and calculating the Earth's radiation budget. These laboratory experiments aid in the interpretation of results from a recent field study, discussed in a companion article (Lack et al. 2008). 相似文献
17.
S. J. Dunnett X. Wen S. K. Zaripov R. S. Galeev M. V. Vanunina 《Aerosol science and technology》2013,47(7):490-502
The performance of an idealized spherical sampler facing both vertically upwards and downwards in calm air is studied numerically. To describe the air flow around the sampler, both potential and viscous flow models have been adopted. The equations of particle motion are then solved to calculate the aspiration efficiency. The dependence of the aspiration efficiency upon the various parameters of importance in calm air sampling are investigated and compared where possible with the experimental work of Su and Vincent (2003, 2004a, b). It is found that in the case of upwards sampling the bluntness of the sampler only has a significant effect upon aspiration for large sampling velocities, values that would not generally be physically realistic. In the case of downwards sampling an important non-dimensional quantity, B 2 R C , is identified, where B represents the sampler bluntness and R C represents the gravitational effects. This quantity determines the physical conditions for which aspiration will not occur and also the limiting values of the aspiration efficiency when aspiration does occur. In the case of low sampling velocities a difference is noted between experimental and numerical results for aspiration efficiency raising the need for more experimental data in this area. For both upwards and downwards sampling the semi-empirical models of Su and Vincent (2004b) have been modified to account for the information gained from the study. This is particularly important in the downwards sampling case where the modified model is found to agree particularly well with the results obtained. 相似文献
18.
Yasumitsu Uraki Chinatsu Matsumoto Takuro Hirai Yutaka Tamai Makiko Enoki Hiroshi Yabu 《木材化学与工艺学杂志》2013,33(4):348-359
Abstract We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall.[ 1 , 2 ] The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions. 相似文献
19.
A variant of the Vienna DMA (Winklmayr et al. 1991; Reischl et al. 1997) with inner and outer electrode radii of 25 and 33 mm, and a conventional trumpet inlet diameter of 97 mm has been tested. It incorporates a reduced pressure drop sheath gas exhaust system that enables reaching flow rates approaching 4000 L/min. Several new additional flow features are included to delay the transition to turbulent conditions. A cylindrical geometry with a DMA length L of 97 mm (distance between the aerosol inlet and outlet slits) is seen to keep the flow laminar up to the highest Reynolds number achieved, though showing slight signs of flow quality deterioration at about Re = 20,000. An equally long DMA with an inner electrode shaped as a 5° cone caped by a spherical dome remains stable up to the highest Reynolds number achieved. It is expected to continue this trend to considerably higher flow rates. Both these long configurations exhibit line widths close to the ideal Brownian diffusion limit, reaching FWHH of 4% for a particle mass diameter of 1 nm. A short DMA with an axial length L of 18 mm and an inner electrode shaped as a 5° cone caped by an ellipse of 3/2 aspect ratio remains also laminar at the highest speeds attained, and exhibits FWHH as small as 2.4%. It departs moderately from ideal behaviour at small flow rates, presumably due to its non-cylindrical geometry. More serious departures observed at high Reynolds numbers may perhaps be due to flow unsteadiness radiated into the working section by sound waves from the turbulent exhaust region. This is the first report of a DMA capable of excellent resolution at 1 nm, yet with a sufficiently wide and long working section to enable (in principle) covering the size range up to 100 nm. 相似文献
20.
A quasi-one-dimensional model of the process of continuous sedimentation in clarifier-thickeners (settlers) with variable cross-sectional area is presented. The partial differential equation (PDE) model extends the settler model advanced by Bürger et al. (2013), which assumes a constant cross section. A reliable numerical method that handles the special features of the nonlinear PDE is presented along with an advantageous time-step condition for continuous and batch sedimentation under the condition of a variable cross-sectional area. Simulations of continuous sedimentation show the effect of change of cross-sectional area in the concentration inside the vessel and in the underflow. Simulations of batch settling in cones illustrate the versatility of the numerical scheme to include a vertex, where the area shrinks to zero. 相似文献