大气有机物预浓缩用吸附剂富集特性的气相色谱法研究

用气相色谱方法研究了吸附剂对大气有机物的富集特性,提出用吸附参数泄漏体积ＢＴＶ（最大采样体积）以及脱附参数最低脱附温度或最小吹扫体积作为富集指标的新思想,并用冲洗色谱法测定了一些有机物在ＧＤＸ－３０１上的特性参数。不同温度的特性参数由１ｏｇ（ＢＴＶ）与１／Ｔｃ的线性关系外推得到。实验表明,所研究的２０种有机物（除了甲醇外）在装有２ｇＧＤＸ－３０１的采样管和０．１４ｇＧＤＸ－３０１的聚焦管上的最大采样体积分别不小于０．８Ｌ（３５℃）和０．３Ｌ（０℃）。     

松油醇的分析及其生产工艺改进的研究

 应用气相 红外光谱(GC FTIR)和气相 质谱(GC MS)对合成松油醇及其杂质成分、原料松节油、合成过程中间体粗油(红油和黄油)和天然松油醇进行了分析研究,为判断松油醇产品中杂质产生的原因及改进生产工艺提供了依据。研究结果表明,松油醇中的杂质主要为长叶烯和石竹烯,是由原料松节油带入的。天然松油醇粗油中主要成分是1,8 桉叶素、反式 4 艹守醇、p 异丙烯基甲苯、顺式 4 艹守醇、芳樟醇、樟脑、龙脑、4 松油醇、α 松油醇和黄樟素。天然松油醇中β 松油醇和γ 松油醇含量不如合成松油醇中的含量高,以此可判断松油醇是天然的还是合成的。     

Stability of phenolic compounds during extraction with superheated solvents

The stability of nine phenolic compounds in the extraction with superheated methanol at different temperatures (40, 50, 100 and 150 degrees C) has been tested. The evolution of the same compounds in boiling methanol (65 degrees C) in contact with air was also determined. All the assayed phenolic compounds were stable under the extraction conditions with the exception of catechin and epicatechin (recoveries: 87.4% for catechin and 86.0% for epicatechin at 150 degrees C and 94.1% for epicatechin at 100 degrees C). Phenolic compounds kept at the boiling point of methanol (65 degrees C) showed lower recoveries: gentisic acid (85.5%), syringic aldehyde (92.8%), catechin (63.7%) and epicatechin (63.4%). Extraction with superheated solvents was also applied to the extraction of phenolic compounds from solid wastes of the winemaking process.     

Temperature requirements for thermal modulation in comprehensive two-dimensional gas chromatography

Temperature requirements for trapping and release of compounds in a cryogenic gas loop-type GC x GC modulator were determined. Maximum trapping temperatures on the uncoated, deactivated modulator capillary were determined for compounds from C4 (bp -0.5 degrees C) to C40 (bp 522 degrees C). The liquid-nitrogen cooled gas flow rate was reduced from a high of 15.5 to 1.5 SLPM over the range to achieve the required trapping temperature. Excessive cold jet flow rates caused irreversible trapping and peak tailing for semi-volatile compounds above C26. Alternate cold jet coolants were investigated. An ice water-cooled jet was able to trap compounds with boiling points from C18 (bp 316 degrees C) to C40 and a room temperature air-cooled jet was able to trap compounds from C20 (bp 344 degrees C) to C40. The hot jet produced launch temperatures approximately 40 degrees C hotter than the elution temperature with heating time constants of 8 to 27 ms. Modulated compound peaks were symmetrical with half-height peak widths of 43 to 56 ms for compounds with little second column retention, and 70 to 75 ms for compounds with more second column retention. The liquid nitrogen-cooled loop modulator with gas flow programming was used to produce a GC x GC chromatogram for a crude oil that contained compounds from C7 to C47.     

Comparison of the X-ray crystallography of undecafluorocyclohexane, C(6)HF(11), with that of dodecafluorocyclohexane, C(6)F(12)

A comparison of undecafluorocyclohexane and dodecafluorocyclohexane shows that both exist at 23 degrees in face-centred cubic cells with edges a(0) = 10.00 +/- 0.02 A for C(6)HF(11) and a(0) = 10.11 +/- 0.02 A for C(6)F(12). The X-ray data are consistent with internal rotation of the molecules or statistical randomness of the molecules in the compounds.     

Surface cosegregation on Fe-3%V-C,Fe-3%V-C,N and Fe-15%Cr-N (110) single crystals

Surface cosegregation has been studied on (110) oriented Fe-3%V-C, Fe-3%V-C,N and Fe-15%Cr-N single crystals applying AES and LEED. The surface compounds VC,V(C,N) and CrN are formed upon annealing in the temperature range from 450 to 750 degrees C depending on the alloy. The stoichiometries of the binary surface compounds correspond to VC(1.2) and approximately CrN(0.8) as determined by quantitative evaluation of Auger peak height ratios. The composition of the V(C,N) surface compound varies between V(C(0.6)N(0.6)) at 450 degrees C and V(C(0.2)N(1.0)) at 640 degrees C. Three-dimensional precipitates are not formed as indicated by Ar(+) depth profiling. After short annealing times streaking LEED patterns are observed indicating partial disorder in one direction of the direct space. Upon sufficient annihilation of surface defects sharp (4 x 1) patterns appear. A missing and added row "model" is proposed for the surface compounds on bcc(110) substrate surfaces.     

Ph(3)PCH(2)Ph](2)[Zn(3)(tp)(3)Cl(2)] and Ni(3)(tma)(2)(H(2)O)(8): two unusual claylike frameworks of metal-polycarboxylate coordination polymers (tp = terephthalate, tma = trimesate)

Two new compounds, [Ph3PCH2Ph]2[Zn3(tp)3Cl2] (1) and Ni3(tma)2(H2O)8 (2) (tp = terephthalate, tma = trimesate), are metal-polycarboxylate coordination polymers prepared by similar hydrothermal synthesis techniques. X-ray single-crystal structural analysis shows that both compounds crystallize in the 2D claylike lamellar architectures, in which 1 possesses the interlayer [Ph3PCH2Ph]+ exchangeable cation and has been confirmed by PXRD patterns. 1 (C74H56Cl2O12P2Zn3) belongs to monoclinic P21/c, Z = 2 (a = 18.956(1) A, b = 10.2697(5) A, c = 17.067(1) A, beta = 99.486(4) degrees ). 2 (C18H22O20Ni3) is attributed to triclinic P, Z = 1 (a = 6.6643(8) A, b = 9.622(1) A, c = 10.089(1) A, alpha = 112.675(2) degrees , beta = 94.007(1) degrees, gamma = 106.411(2) degrees ). Linear metal trinuclear clusters bridged by rigid linear tp ligands for 1 and trigonal tma ligands for 2 give rise to a novel 2D 6-linked (3,6) topological anionic network in 1 and an interesting 2D 3,6-linked molybdenite topological neutral network in 2, respectively. Both compounds exhibit intense fluorescent emission bands at 410 nm (lambda(exc) = 355 nm) for 1 and 398 nm (lambda(exc) = 300 nm) for 2 in the solid state at room temperature.     

Synthesis, tautomeric states and crystal structure of (Z)-ethyl 2-cyano-2-(3H-quinazoline-4-ylidene) acetate and (Z)-ethyl 2-cyano-2-(2-methyl-3H-quinazoline-4-ylidene) acetate

The new compounds (Z)-ethyl 2-cyano-2-(3H- and 2-methyl-3H-quinazoline-4-ylidene) acetate (1 and 2, respectively) were synthesized by multi-step reactions. The structures in a solution have been determined by (1)H-NMR spectroscopy and in the crystal form by X-ray analysis. Molecule 1 crystallized in a primitive monoclinic cell, space group capital ER, P2(1/c). The cell dimensions are a=7.970(6) A, b=7.061(2) A, c=20.537(7) A, beta=97.69(5) degrees , V=1145.3(10) A(3). Molecule 2 crystallized in a triclinic cell, space group P-1, the cell dimensions are a=8.196(5) A, b=8.997(6) A, c=9.435(4) A, alpha=74.22(4) degrees, beta=89.75(4) degrees , gamma=74.07(5) degrees , V=641.9(6) A(3). In both compounds the presence of intra-molecular NH---O=C hydrogen bonding between the nitrogen atom in position 3 of the quinazoline ring and a carbonyl group of the ethyl cyanoacetate residue was proven by quantum-chemical, (1)H-NMR and X-ray methods.     

Mosaic increments for predicting the gas chromatographic retention data of the chlorobenzenes

The chlorinated organic compounds are very important from the point of view of the chemical industry and environmental protection, and therefore the gas chromatographic analysis of these compounds is very interesting for analytical chemists. In this paper we studied the relationship between the molecular structure and gas chromatographic retention on several stationary phases having different polarity and at several temperatures of benzene and 12 chlorobenzene compounds as model compounds. A coding system involving primary (mosaic increments) and secondary (bond increments)calculation methods was developed. The retention indices of benzene and the chlorobenzenes calculated on HP-5 at 120 degrees C shows a better performance of the mosaic increments (average absolute deviation delta of 1.7 retention index units) compared with the bond increments (delta = 11.7 retention index units). Retention factors, k, calculated with mosaic increments for chlorobenzenes on SPB-1 and WAX-10, at 140 degrees C, yield average relative errors of epsilon = 0.9 and 3.5%, respectively. Therefore, the presented paper provides a new possibility for precalculation of the retention data.     

APdCu(Se2)(Se3) (A = K and Rb): new quaternary copper palladium polyselenides with unusual metal-selenium coordination

Two novel metal polyselenides, KPdCu(Se(2))(Se(3)) (I) and RbPdCu(Se(2))(Se(3)) (II), have been synthesized from solvothermal reactions in superheated ethylenediamine at 160 degrees C. The isostructural compounds crystallize in the monoclinic space group P2(1)/m, Z = 2, with a = 6.145(1) A, b = 7.268(1) A, c = 8.865(2) A, beta = 102.41(3) degrees for I, and a = 6.253(1) A, b = 7.267(1) A, c = 8.993(2) A, beta = 102.28(3) degrees for II. Their crystal structures are two-dimensional networks with [PdCu(Se(2))(Se(3))](-) anionic layers built from one-dimensional [Pd(Se(2))(Se(3))](2)(-) "chains" that are "stitched" together by tetrahedrally coordinated Cu atoms. The DSC data show that I and II are stable up to 400 degrees C and decompose at ca. 436 and 424 degrees C, respectively. Both compounds are narrow band-gap semiconductors with estimated band gaps of about 0.7 eV (I) and 0.8 eV (II), respectively. They are the first structurally characterized quaternary copper palladium polychalcogenides with a (Se(2))(2)(-) and a (Se(3))(2)(-) fragment, both exhibiting interesting and unusual metal-selenium coordination.     

Ternary alkali metal transition metal acetylides A2MC2 (A = Na, K; M = Pd, Pt)

Ternary transition metal acetylides A2MC2 (A = Na, K; M = Pd, Pt) can be synthesised by reaction of the respective alkali metal acetylide A2C2 with palladium or platinum in an inert atmosphere at about 350 degrees C. The crystal structures are characterised by (infinity)1[M(C2)(2/2)2-] chains, which are separated by the alkali metals (P3m1, Z = 1). The refinement of neutron powder diffraction data gave C-C = 1.263(3) A for Na2PdC2 (Na2PtC2: 1.289(4) A), which is distinctively longer than the expected value for a C-C triple bond (1.20 A). On the basis of band-structure calculations this can be attributed to a strong back-bonding from the metal into the anti-bonding orbitals of the C2 unit. This was further confirmed by Raman spectroscopic investigations, which showed that the wavenumbers of the C-C stretching vibrations in Na2PdC2 and Na2PtC2 are about 100 cm(-1) smaller than in acetylene. 13C MAS-NMR spectra demonstrated that the acetylenic C2 units in the title compounds are very different from those in acetylene. Electrical conductivity measurements and band-structure calculations showed that the black title compounds are semiconductors with a small indirect band gap (approximately 0.2 eV).     

The Diammoniates of dipotassiumtetraethinylozincate and -cadmate: K2M(C2H)4.2NH3 (M = Zn, Cd)

By reaction of KC(2)H and K(2)Zn(CN)(4) in liquid ammonia, the diammoniate K(2)Zn(C(2)H)(4).2NH(3) was obtained. K(2)Cd(C(2)H)(4).2NH(3) was synthesized by reacting KC(2)H, Cd(NH(2))(2), and acetylene in liquid ammonia. The crystal structures of the air and temperature sensitive compounds were determined by X-ray single crystal diffraction at low temperatures (T = 170 K). Both compounds crystallize in the monoclinic space group I2/a (No. 15) with Z = 4. K(2)Zn(C(2)H)(4).2NH(3): a = 7.289(1) A, b = 12.765(2) A, c = 14.066(2) A, beta = 98.11(2) degrees. K(2)Cd(C(2)H)(4).2NH(3): a = 7.444(1) A, b = 12.619(3) A, c = 14.304(2) A, beta = 98.94(1) degrees. Characteristic structural motifs are tetrahedral [M(C(2)H)(4)](2-) fragments (M = Zn, Cd) and zigzag chains of edge sharing distorted (C(2)H)(6) octahedra centered by potassium ions. These zigzag chains are connected by a second type of crystallographically distinct potassium ions that also bind to two ammonia molecules.     

Effects of water uptake on the inherently oxygen-deficient compounds Ln26O27 square(BO3)8 (Ln=La, Nd)

The inherently oxygen-deficient compounds Ln26O27 square(BO3)8 (Ln=La, Nd) react with water vapor leading to Ln26O26(OH)2(BO3)8 phases, and this reaction is reversible. The crystal structure of Nd26O27 square(BO3)8 has been determined from single-crystal data (space group P with a=6.7643(10) A, b=12.663(2) A, c=14.271(2) A, alpha=90.553(8) degrees, beta=99.778(10) degrees, and gamma=90.511(9) degrees). It is a triclinic distorted version of the monoclinic structure of La26O27 square(BO3)8. The Ln26O26(OH)2(BO3)8 phases both crystallize in the monoclinic system (space group P21/c with a=6.7445(4) A, b=12.6177(9) A, c=14.4947(10) A, and beta=100.168(7) degrees for Nd26O26(OH)2(BO3)8 and a=6.9130(15) A, b=12.896(3) A, c=14.792(4) A, beta=99.698(16) degrees for La26O26(OH)2(BO3)8), and their crystal structure has been determined from single-crystal data, showing that the hydroxyl groups are localized mainly on one of the oxygen sites at room temperature (RT). For the Nd phases, the change in crystal system can result from two different phenomena depending on the atmosphere, either a phase transformation corresponding to a water uptake under wet conditions (triclinic Nd26O27 square(BO3)8 at RT-->monoclinic Nd26O26(OH)2(BO3)8) or a phase transition at approximately 300 degrees C for the anhydrous phase under dry conditions (triclinic Nd26O27 square(BO3)8 at RT-->monoclinic Nd26O27 square(BO3)8 at T>300 degrees C). For Nd26O26(OH)2(BO3)8, the conductivity measured under wet conditions at 300 degrees C is sigma300 degrees C approximately 0.5x10(-5) S cm(-1). Due to the dehydration process, the proton contribution to the total conductivity of the Nd phase is no longer observed above 500 degrees C whereas it was still clearly visible at 600 degrees C for the La phase.     

Syntheses and structural characterization of the (OCnOPor) capped porphyrins: Co(OC2OPor).CH2Cl2, Co(OC2OPor)(NO)out.0.46CHCl3, Co(OC3OPor).CHCl3, and Co(OC3OPor)(MeIm).3C7H8

The compounds Co(OC2OPor).CH2Cl2 (1), Co(OC2OPor)(NO)out.0.46CHCl3 (2), Co(OC3OPor).CHCl3 (3), and Co(OC3OPor)(MeIm).3C7H8 (4) (OC2OPor = 5,10,15,20-(benzene-1,2,4,5- tetrakis(2-phenyloxy)ethoxy)-2',2",2"',2"-tetraylporphyrinato dianion; OC3OPor = 5,10,15,20-(benzene-1,2,4,5-tetrakis(2- phenyloxy)propoxy)-2',2",2"',2"-tetraylporphyrinato dianion; MeIm = 1-methylimidazole), have been synthesized, and their structures have been determined by single-crystal X-ray diffraction methods at T = -120 degrees C: 1, a = 8.824(1) A, b = 16.674(1) A, c = 16.836(1) A, alpha = 104.453(1) degrees, beta = 92.752(1) degrees, gamma = 90.983(1) degrees, P1, Z = 2; 2, a = 9.019(1) A, b = 16.588(2) A, c = 16.909(2) A, alpha = 103.923(2) degrees, beta = 92.082(2) degrees, gamma = 93.583(2) degrees, P1, Z = 2; 3, a = 13.484(3) A, b = 14.404(3) A, c = 14.570(3) A, alpha = 105.508(3) degrees, beta = 100.678(3) degrees, gamma = 93.509(4) degrees, P1, Z = 2; 4, a = 16.490(1) A, b = 22.324(2) A, c = 17.257(1) A, b = 92.437(1) degrees, P2(1)/n, Z = 4. These compounds are the first structurally characterized Co-bound members of the OCnOPor ligand system. The NO ligand in 2 and the MeIm ligand in 4 bind asymmetrically and lead to several metrical changes in these porphyrins, e.g., variations in average porphyrin deviations and Co atom displacements relative to the porphyrinato N atoms and the mean porphyrin planes.     

Performance of capillary columns for high-temperature gas chromatography

The developments in stationary-phase synthesis and capillary column technology have opened new perspectives in the analysis of high-molecular-weight compounds (600 daltons) and thermolabile organic compounds by high-temperature-high-resolution gas chromatography. This branch of high-resolution gas chromatography deals with analysis performed up to 390 degrees C oven temperature (with some applications going up to 420 degrees C and even a few applications to 450 degrees C maximum). The technique has been applied to many different fields of science (e.g., organic geochemistry, environmental chemistry, archeology, and natural product research). Apolar and medium-polar gum phases can now be operated at temperatures from 400 to 480 degrees C, but these higher temperatures are seldom used because of the thermostability of the material used to make the capillary tubing. This paper shows the performance of nine commercial high-temperature columns when used in routine applications.     

Low melting inorganic salts of alkyl-, fluoroalkyl-, alkyl ether-, and fluoroalkyl ether-substituted oxazolidine and morpholine

N-Alkyl- and N-fluoroalkyl-substituted oxazolidinium- and morpholinium-based quaternary salts and ionic liquids have been synthesized and characterized. Reactions of N-methyloxazolidine (1) or N-methylmorpholine (2) with 3-fluoropropyl bromide or iodopropane in THF at 25 degrees C gave the quaternary salts (3a,b, 4a,b). These salts were metathesized with various metal salts to yield the corresponding ionic liquids (5a-h, 6a-i). N-Alkoxyethyl- and N-(fluoroalkoxy)ethyl-substituted morpholines (8-11) were prepared and quaternized with methyl iodide (8a-11a). Their corresponding ionic liquids (12-18) were obtained by anion exchange and characterized. For both series of compounds, nitrate, hexafluorophosphate, perchlorate, triflate, and bis(trifluoromethanesulfonyl)amide were utilized. Most of the final products are liquids at 25 degrees C and are thermally stable with long liquid ranges as determined by thermal gravimetric analyses. For compounds 12, 16, and 18, thermal stabilities of > or =400 degrees C were observed. All the new compounds were characterized by spectroscopic and elemental analyses. Their densities and viscosities were also determined.     

Calibration system and analytical considerations for quantitative sesquiterpene measurements in air

Sesquiterpenes (C15H24, SQT) are semi-volatile organic compounds emitted from vegetation and are of interest for air quality considerations because of their suspected contribution to the formation of secondary aerosol. This article investigates the application of a capillary diffusion method for the generation of standard atmospheres of 16 SQT and four other related semi-volatile compounds. This instrument subsequently has been used in the testing of analytical materials, protocols and calibration of air sampling methods. SQT DB-1 retention indices, vapor pressures at 25 and 75 degrees C, and diffusion coefficients were determined. A quantitative, on-line GC method yielded improved results (median relative standard deviation of 5.0-6.1%) for the diffusion rate determination in comparison to a gravimetric approach (median relative standard deviation 18%). The GC method also allowed identifying errors in the gravimetric method stemming from residual solvent evaporation, impurities, and chemical analyte losses. Stainless steel, glass, nickel and PTFE tubing that were tested for transfer lines and a sampling loop had to be kept at temperatures in excess of approximately 110 degrees C in order to prevent significant analytical errors from the stickiness of SQT to these materials. In addition to SQT analysis, results from this research provide general guidelines for gas-phase analysis of related compounds in the C14-C16 volatility range.     

Niobium-arsenic Zintl phases: A(6)NbAs(5) (A = K,Rb, Cs), K(6)NbTlAs(4), and K(8)NbPbAs(5) with edge-bridged niobium-centered tetrahedra of arsenic, [NbAs(4)M](n-) where M = As,Tl, Pb

The five title compounds were prepared by direct reactions of the corresponding elements at high temperature. Their structures contain isolated anions of tetrahedral NbAs(4) where one of the edges of the tetrahedron is bridged by a third atom. The bridging atom is arsenic in A(6)NbAs(5) (monoclinic, P2(1)/c, Z = 8; with a = 25.774(3) A, b = 9.335(1) A, c = 13.012(1) A, beta = 101.05(1) degrees for A = K; a = 27.629(1) A, b = 9.925(1) A, c = 14.111(1) A, beta = 101.63(1) degrees for A = Rb; and a = 27.405(1) A, b = 9.9447(6) A, c = 13.9964(8) A, beta = 101.210(1) degrees for A = Cs), thallium in K(6)NbTlAs(4) (orthorhombic, Pnma, Z = 4, a = 18.786(1) A, b = 10.4442(4) A, c = 7.715(1) A), and lead in K(8)NbPbAs(5) (monoclinic, C2/c, Z = 8, a = 31.597(9) A, b = 9.353(1) A, c = 13.427(2) A, beta = 95.25(1) degrees ). The lead atom in the latter is bonded to a third arsenic atom as well. Magnetic measurements showed diamagnetic behavior, and therefore, the compounds are electronically balanced, closed-shell type compounds and can be described as transition-metal Zintl phases. The bonding in the anion NbAs(5)(6-) is discussed in detail.     

气相-质谱分析北细辛根和根茎中的挥发性成分

 采用 质谱联用技术对北细辛根和根茎的挥发性成分进行分离分析 ,鉴定出了 36种化学成分 ,主要成分为十五烷、甲基丁香酚、黄樟醚、3 ,5 二甲氧基甲苯等。对照北细辛根和根茎的分析结果可以发现 ,两者的挥发性成分基本相同 ,但含量有较大差异 ,这为北细辛的临床合理用药及质量控制标准的确定提供了实验依据。