有化学作用时气体在液体中的溶解度

在一定温度下,难溶性气体在液体中的溶解度与气相中气体的平衡分压之间的关系用亨利定律描述: P_2=k_mm_2 (1)式中“2”表示气体溶质,P_2是与液体呈平衡的气相中溶质的分压,单位为atm,m_2是溶质的溶解度,     

以8-羟基喹啉为化学改进剂石墨炉原子吸收光谱测定水和空气尘粒物中铬的研究

研究了8－羟基喹啉在石墨炉原子吸收光谱法（GFAAS）测定痕量铬中的化学改进作用及其主要影响因素。在优化实验条件下，8－羟基喹啉的存在能显著提高石墨炉原子吸收法测定铬的灵敏度。方法的检出限为0．20ng/mL，精密度为RSD＝2．6％（n＝8，c＝5ng/mL），本法已用于天然水和大气尘粒物中痕量铬的测定。     

测定血浆中微量硒的三元包合物荧光分析法

采用氧瓶燃烧法对血样进行破坏,利用β－环糊精和十二烷基硫酸钠形成包合物的性质,将4,5－苯并苯硒二唑包合,建立了三元包合物荧光分析法,不经萃取,直接测定血浆中的硒。方法的日内精密度为5．4％－9．3％（n＝7）;日间精密度为3．5％－14．5％（n＝7）;线性范围为10－500μg／;回收率为91．0％－97．8％。对新疆汉族、维吾尔族和沈阳汉族58人的血样进行测定,结果表明：新疆汉族与沈阳汉族间血硒值无显著性差异（F＝1．36,P＞0．05）;新疆汉族与维吾尔族间血硒值有非常显著性差异（F＝1．01,P＜0．01）;男女之间血硒值有非常显著性差异（P＜0．01）。     

阴离子合成洗涤剂检测方法的比较和探讨

对5－Br－PADAP钴法和二氮杂菲萃取分光光度法测定水中基苯磺酸盐（ABS）分别进行了空白测定、精密度、准确度、标准物质测定等对比试验。结果表明，两者无显著性差异，但二氮杂菲法更方便，检测成本低，线性范围较广，更适合生活饮用水及不源水中ABS的测定。     

动力学分析法测定气相中的二氧化碳

本文基于气相中的二氧化碳在稀氢氧化钠－酚酞溶液中的溶解而使酚酞逐渐褪色的动力学行为提出了一种直接测定气相中微量二氧化碳的动力学分析法。研究表明，该反应的速率与气相中ＣＯ２的浓度成正比。利用固定浓度法，本文测定了一些模拟样品和环境气体样品，效果良好。该方法仪品简单，样品不必预处理。     

3-X-2(1H)-吡啶酮互变异构体系的理论计算

２（１Ｈ）－吡啶酮类化合物常呈现出诱人的生物活性［１,２］．由于酮式和烯醇式结构具有互变异构化性质,因此确定其互变异构平衡体系中的优势结构及研究取代基对平衡体系的影响,对阐明该类化合物的生物活性及进行构效关系的研究有着重要的意义．当其３－位含有可与２－位羰基或２－位羟基形成分子内氢键的基团时,势必对互变异构平衡产生影响．基于该类化合物的互变异构平衡有着强烈的溶剂效应［３］,本文对３－Ｘ－２（１Ｈ）－吡啶酮（Ｘ＝ＮＯ２,ＮＨ２,ＣＯＯＨ）及其烯醇式互变异构体分别在气相和溶液中进行了理论计算,考察了…     

海水和大气中挥发性硫化物分析方法的研究

建立了大气和海水中挥发性硫化物的气相色谱分析方法,确定了最佳实验条件.为了适应不同的基质和保存方式,大气和海水样品采用了不同的分析方法.测定大气样品时,采用大气采样罐及三级冷阱预浓缩气相色谱-质谱联用技术,而海水样品采用吹扫捕集-气相色谱测定.本方法测定大气挥发性硫化物的线性范围较好,精密度为7.7%~15.1%,检出限为0.23~4.7 ng;海水中挥发性硫化物的精密度为3.5%~5.3%,检出限为2.5~3.5 ng.将本方法用于青岛近海海水和大气中硫化物的测定,测得海水中羰基硫、二甲基硫和二硫化碳的平均浓度分别为(268±58)pmol/L、(1264±0.2)pmol/L、(19±2)pmol/L,大气中的平均浓度为543±39、39±9和56±20(×10-12,V/V).本方法可准确测定海洋环境中的挥发性硫化物.     

鲜魔芋及其种植土壤中矿物元素的ICP-AES法测定

采用电感耦合等离子体原子发射光谱法（ICP－AES）测量了不同产区鲜魔芋球茎及其种植土壤中10种矿物元素的含量，并初步讨论其相关性；采用湿法消化处理样品并考察了不同元素测定的精密度、回收率；测定的相对标准偏差（RSD）均小于2％，回收率为95％－104％，结果可信度高。     

甲氧滴涕原药成分的气相色谱和气相色谱-质谱分析

本文用气相色谱（GC），气相色谱-质谱联用（GC－MS）测定了甲氧滴涕（DMDT）原药中有效成分的含量及11种成分的结构。GC法内标定量结果表明，产品甲氧滴涕原药中有效成份达90％以上。     

一阶紫外导数光谱PLS法直接同时测定硝酸根和亚硝酸根

用偏最小二乘（ＰＬＳ）法解析了ＮＯ_３~－和ＮＯ_２~－混合体系的一阶紫外导数光谱，提出了直接同时测定环境水样中ＮＯ_３~－－Ｎ和ＮＯ_２~－－Ｎ的计算分析法。该法对ＮＯ_３~－和ＮＯ_２~－来说，最低检测浓度分别为９×１０~（－８）和２×１０~（－７）ｍｏｌ·Ｌ~（－１），精密度（ＲＳＤ）分别为２．０５％和２．１２％。用于测定合成水样，平均相对误差在４％以内；用于测定环境水样，结果与标准法相吻合。     

Modeling the kinetics of bubble nucleation in champagne and carbonated beverages

In champagne and carbonated beverages, bubble nucleation was mostly found to take place from tiny Taylor-like bubbles trapped inside immersed cellulose fibers stuck on the glass wall. The present paper complements a previous paper about the thorough examination of the bubble nucleation process in a flute poured with champagne (Liger-Belair et al. J. Phys. Chem. B 2005, 109, 14573). In this previous paper, a model was built that accurately reproduces the dynamics of these tiny Taylor-like bubbles that grow inside the fiber's lumen by diffusion of CO(2)-dissolved molecules. In the present paper, by use of the model recently developed, the frequency of bubble formation from cellulose fibers is accessed and linked with various liquid and fiber parameters, namely, the concentration c(L) of CO(2)-dissolved molecules, the liquid temperature theta, its viscosity eta, the ambient pressure P, the course of the gas pocket growing trapped inside the fiber's lumen before releasing a bubble, and the radius r of the fiber's lumen. The relative influence of the latter parameters on the bubbling frequency is discussed and supported with recent experimental observations and data.     

The reaction of mixtures of [Rh4(CO)12] and triphenylphosphite with carbon monoxide or syngas as studied by high-resolution, high-pressure NMR spectroscopy

The fragmentation and redistribution reactions of [Rh4(CO)12-x{P(OPh)3}x] (x = 1-4) with carbon monoxide have been studied using high-resolution, high-pressure NMR spectroscopy. Under the conditions of efficient gas mixing in a high-pressure NMR bubble column, [Rh4(CO)9{P(OPh)3}3] fragments to give mainly [Rh2(CO)6{P(OPh)3}2]; [Rh4(CO)11{P(OPh)3}] is also observed,implying redistribution of the phosphite ligand and/or recombination of the dimers to tetrameric clusters. Fragmentation of[Rh4(CO)10{P(OPh)3}2] is found to be pressure-dependent giving predominantly [Rh2(CO)6{P(OPh)3}2] at low CO pressure (1-40 bar), and increasing amounts of [Rh2(CO)7{P(OPh)3}] at higher (40-80 bar) pressure. Using Syngas (CO : H2 (1 : 1)) instead of CO in the above fragmentations, homolytic addition of H2 to the dimer [Rh2(CO)6{P(OPh)3}2] to give [RhH(CO)3{P(OPh3}] and [RhH(CO)2{P(OPh)3}2] is observed. The distribution of tetrameric species obtained is similar to that obtained under the same partial pressure of CO. On depressurisation/out-gassing of the sample, the original mixture of tetrameric clusters is obtained.     

Supported absorption of CO2 by tetrabutylphosphonium amino acid ionic liquids

A new type of "task specific ionic liquid", tetrabutylphosphonium amino acid [P(C4)4][AA], was synthesized by the reaction of tetrabutylphosphonium hydroxide [P(C4)4][OH] with amino acids, including glycine, L-alanine, L-beta-alanine, L-serine, and L-lysine. The liquids produced were characterized by NMR, IR spectroscopies, and elemental analysis, and their thermal decomposition temperature, glass transition temperature, electrical conductivity, density, and viscosity were recorded in detail. The [P(C4)4][AA] supported on porous silica gel effected fast and reversible CO2 absorption when compared with bubbling CO2 into the bulk of the ionic liquid. No changes in absorption capacity and kinetics were found after four cycles of absorption/desorption. The CO2 absorption capacity at equilibrium was 50 mol % of the ionic liquids. In the presence of water (1 wt %), the ionic liquids could absorb equimolar amounts of CO2. The CO2 absorption mechanisms of the ionic liquids with and without water were different.     

Hydrate film growth at the interface between gaseous CO_2 and sodium chloride solution

Greenhouse gas CO2 has become a serious problem for human beings. The hydrate technology has been considered as a possible approach to sequester CO2. In this work, the lateral growth rates of a CO2 hydrate film in aqueous NaCl solutions of different concentrations were measured by means of suspending a single gas bubble in liquid. The results show that the film growth rates depended on not only the driving force, but also the NaCl concentration, and the film growth rates decreased with the increasing NaCl c...     

Theoretical study of first-row transition metal porphyrins and their carbonyl complexes

The equilibrium geometry, relative energies, normal mode frequencies, and electron and spin density distributions for first-row transition metal porphyrins M(P) (M is a transition metal in the oxidation state +2, P = C₂₀H₁₂N₄) and their five-and six-coordinate carbonyl complexes M(P)CO and M(P)(CO)(AB) (AB = CO, CN^?, CS) in different spin states have been calculated by the density functional theory B3LYP method with the 6-31G and 6-31G* basis sets. The energies of binding of the CO group to M(P) molecules D(M-CO) have been estimated. The calculated properties change as a function of the metal, the number of carbonyl groups (shown for Fe(P) as an example), and the multiplicity. Calculations show that, for five-coordinate complexes M(P)CO with M = Ti and V, high-spin states and significant D(M-CO) energies are typical. For Fe(P)CO, a singlet with a small D(M-CO) energy is preferable. For Cr(P)CO and Mn(P)CO (which also have small D(M-CO) energies), the states with different spins, which strongly differ in geometry and electronic structure, are close in energy, within 0.1–02. eV. The energy of binding of CO to M(P)CO (M = Cr, Mn, Fe) is considerably higher than the energy of binding of CO to M(P), which is evidence that the transformation of five-coordinate metalloporphyrins into six-coordinate ones is energetically favorable. The behavior of the D(M-CO) energies is interpreted using a qualitative model that considers not only the effects of participation (or nonparticipation) of “active” $ d_{x^2 - y^2 } The equilibrium geometry, relative energies, normal mode frequencies, and electron and spin density distributions for first-row transition metal porphyrins M(P) (M is a transition metal in the oxidation state +2, P = C₂₀H₁₂N₄) and their five-and six-coordinate carbonyl complexes M(P)CO and M(P)(CO)(AB) (AB = CO, CN⁻, CS) in different spin states have been calculated by the density functional theory B3LYP method with the 6-31G and 6-31G* basis sets. The energies of binding of the CO group to M(P) molecules D(M-CO) have been estimated. The calculated properties change as a function of the metal, the number of carbonyl groups (shown for Fe(P) as an example), and the multiplicity. Calculations show that, for five-coordinate complexes M(P)CO with M = Ti and V, high-spin states and significant D(M-CO) energies are typical. For Fe(P)CO, a singlet with a small D(M-CO) energy is preferable. For Cr(P)CO and Mn(P)CO (which also have small D(M-CO) energies), the states with different spins, which strongly differ in geometry and electronic structure, are close in energy, within 0.1–02. eV. The energy of binding of CO to M(P)CO (M = Cr, Mn, Fe) is considerably higher than the energy of binding of CO to M(P), which is evidence that the transformation of five-coordinate metalloporphyrins into six-coordinate ones is energetically favorable. The behavior of the D(M-CO) energies is interpreted using a qualitative model that considers not only the effects of participation (or nonparticipation) of “active” , and , d _xz , and d _yz AO in bonding of M to the P ring and axial ligands, but also the fraction of the total bond energy consumed for the preparation (promotion) of those “valence states” of the M(P) molecules that are realized in M(P)CO and M(P)(CO)(AB) complexes. For the series of compounds Fe(P)(CO)₂ − Fe(P)(CO)(CS) − Fe(P)(CS)₂ − Fe(P)(CO)(CN⁻) in the singlet, triplet, and ionized states, the trans influence of axial ligands in low-spin metalloporphyrins is shown to follow the same qualitative scheme as is typical of octahedral transition metal complexes: in mixed-ligand complexes (as compared to the symmetric ones), the stronger bond becomes shorter and even stronger, while the weaker bond becomes longer and even weaker. It is assumed that the same scheme will persist for more complicated low-spin six-coordinate metalloporphyrins in the states with the vacant AO and occupied d _xz and d _xz AOs involved in bonding with both axial ligands with the filled shell. Original Russian Text ? O.P. Charkin, A.V. Makarov, and N.M. Klimenko, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 5, pp. 781–794.     

Sensitive and selective chromogenic sensing of carbon monoxide via reversible axial CO coordination in binuclear rhodium complexes

The study of probes for CO sensing of a family of binuclear rhodium(II) compounds of general formula [Rh(2){(XC(6)H(3))P(XC(6)H(4))}(n)(O(2)CR)(4-n)]·L(2) containing one or two metalated phosphines (in a head-to-tail arrangement) and different axial ligands has been conducted. Chloroform solutions of these complexes underwent rapid color change, from purple to yellow, when air samples containing CO were bubbled through them. The binuclear rhodium complexes were also adsorbed on silica and used as colorimetric probes for "naked eye" CO detection in the gas phase. When the gray-purple colored silica solids containing the rhodium probes were exposed to air containing increasing concentrations of CO, two colors were observed, in agreement with the formation of two different products. The results are consistent with an axial coordination of the CO molecule in one axial position (pink-orange) or in both (yellow). The crystal structure of 3·(CO) ([Rh(2){(C(6)H(4))P(C(6)H(5))(2)}(2)(O(2)CCF(3))(2)]·CO) was solved by single X-ray diffraction techniques. In all cases, the binuclear rhodium complexes studied showed a high selective response to CO with a remarkable low detection limit. For instance, compound 5·(CH(3)CO(2)H)(2) ([Rh(2){(m-CH(3)C(6)H(3))P(m-CH(3)C(6)H(4))(2)}(2)(O(2)CCH(3))(2)]·(CH(3)CO(2)H)(2)) is capable of detection of CO to the "naked eye" at concentrations as low as 0.2 ppm in air. Furthermore, the binding of CO in these rhodium complexes was found to be fully reversible, and release studies of carbon monoxide via thermogravimetric measurements have also been carried out. The importance of the silica support for the maintenance of the CO-displaced L ligands in the vicinity of the probes in a noninnocent manner has been also proved.     

混合吸附剂在环境监测中分析苯系物的性能考察

探讨了单一吸附剂和混合吸附剂对大气中苯系物的回收率,同时对比了一些洗液,发现用二氯甲烷代替二硫化碳可取得更好的结果,因为前者不仅回收率高于后者,且更有利于减少环境污染。     

Determination of oil–water partition coefficients of polar compounds: silicone membrane equilibrator vs. SPME passive sampler

Experimental determination of oil-water partition coefficients often poses difficulties associated with emulsion formation. The aim of this work was to find an appropriate technique for determination of oil–water partition coefficients of polar, nonvolatile compounds. Two different methods were tested. The first method used a “silicone membrane equilibrator.” For the second method, solid-phase microextraction (SPME) fibers with a polyacrylate (PA) coating were used as a passive sampler. With both methods, oil–water partition coefficients for 14 compounds with polar functional groups were determined at 37 °C with good repeatability (standard deviation 0.11 log units or lower). The partition coefficients determined with the silicone membrane equilibrator method ranged from 0.50 to 3.49 log units. The oil–water partition coefficients obtained with the PA-SPME passive sampling approach were significantly higher than those obtained with the silicone membrane equilibrator method for nine of 14 compounds. The differences were up to 0.39 log units (i.e., a factor of 2.5). Additional experiments suggested that this difference occurred because the sorption properties of the PA fibers used were influenced by the surrounding phase, e.g., through swelling of the polymer phase. Therefore, the SPME passive sampling method using PA fibers seems to be less reliable, whereas the silicone membrane equilibrator method was found to be a convenient technique for the determination of oil–water partitioning.     

Formation of a reversible, intramolecular main-group metal-CO2 adduct

The P,P-chelated stannylene [(i-Pr(2)P)(2)N](2)Sn takes up 2 equiv of carbon dioxide (CO(2)) to form an unusual product in which CO(2) binds to the Sn and P atoms, thus forming a six-membered ring complex. Gentle heating of the solid product releases CO(2), indicating that CO(2) is bound as an adduct to the main-group complex. The groups bound to the CO(2) fragment are not particularly sterically crowded or highly acidic, thus indicating that "frustrated" Lewis acid-base pairs are not required in the binding of CO(2) to main-group elements.     

Is the wall of a cellulose fiber saturated with liquid whether or not permeable with CO2 dissolved molecules? Application to bubble nucleation in champagne wines

In this paper, the transversal diffusion coefficient D perpendicular of CO2 dissolved molecules through the wall of a hydrated cellulose fiber was approached, from the liquid bulk diffusion coefficient of CO2 dissolved molecules modified by an obstruction factor. The porous network between the cellulose microfibrils of the fiber wall was assumed being saturated with liquid. We retrieved information from previous NMR experiments on the self-diffusion of water in cellulose fibers to reach an order of magnitude for the transversal diffusion coefficient of CO2 molecules through the fiber wall. A value of about D perpendicular approximately 0.2D0 was proposed, D0 being the diffusion coefficient of CO2 molecules in the liquid bulk. Because most of bubble nucleation sites in a glass poured with carbonated beverage are cellulose fibers cast off from paper or cloth which floated from the surrounding air, or remaining from the wiping process, this result directly applies to the kinetics of carbon dioxide bubble formation from champagne and sparkling wines. If the cellulose fiber wall was impermeable with regard to CO2 dissolved molecules, it was suggested that the kinetics of bubbling would be about three times less than it is.