有机同系物密度递变规律

有机同系物密度递变规律曹晨忠（湘潭师范学院化学系，湘潭４１１１００）密度是有机化合物的一个基本物理性质，人们一直在探求有机化合物的结构与密度的关系。梅平￣［１］等曾用拓扑指数讨论直链饱和烃取代衍生物的密度变化，结果与实验的符合程度较好。然而文献［１］...     

有机同系物表面张力递变规律研究

以有机同系物结构重复单元数值连续变化为模型,获得了描述有机同系物表面张力递变规律的数学表达式：σ＝（α0＋α1n＋α2n^2）／（1＋b2n^2）,其中α0,α1,α2,b2均为常数,n为结构重复单元数值,σ为同系物的表面张力,通过非线性回归分析,得到回归方程,结果表明,各类有机同系物的表达张力与重复单元数值满足上述关系式,均显示优良的相关性。     

有机同系物的指数型同系线性规律（Ⅰ）—光电子能谱数据的验证

本文提出一种未报道过的指数型同系线性规律，其表示式为：Ｐ＝ａ＋ｂｅｘｐ｛（ｋ＋１）／（２Ｎ＋３）｝用有机共轭同系物和非共轭同系物的光电子能谱数据对该线性规律进行了验证。     

正烷基环己烷同系物凝聚型物理性质递变规律

以H—(CH2)n—环己烷同系物结构重复单元数值n连续变化为模型,获得了描述该同系物凝聚型物理性质P递变规律的数学表达式:P=a+bnc,其中a、b、c均为常数,n为结构重复单元数值,P为同系物的凝聚型物理性质.通过非线性回归分析,得到回归方程 结果表明该同系物的凝聚型物理性质与重复单元数值之间显示优良的相关性.     

直链烷烃结构型和凝聚型性质的递变规律研究

用图示法和非线性规划的方法对直链烷烃同系物最高成键分子轨道能级、最低成键分子轨道能级,电离电位、氧化半波电位、正常沸点、正常熔点、临界压力、临界温度、密度、折光率、表面张力和粘度等12种结构型性质和凝聚型性质的变化规律进行研究,结果发现直链烷烃结构型性质和凝聚型性质一般能遵守同系对数递变规律,各种结构型性能和凝聚型性能均与对数递变函数呈优良的相关性,相关系数均大于0.99．用同系对数递变规律对直链烷烃各种性能进行预测的结果表明,除少数同系列起始化合物的偏差较大外,大多数预测值与实验值非常吻合,实验散点几乎与对数递变函数曲线相重合．     

烷烃加和型性质的拓扑同系递变规律研究

用分子中原子的平衡电负性对分子图进行着色, 在距离矩阵的基础上结合分子中各原子的支化度构建一组拓扑指数ND, 它对分子结构实现唯一性表征, 具有优良的结构选择性, 用ND指数对链烷烃的加和型性质及同系递变规律进行研究, 结果表明烷烃加和型性质P可用下式来定量描述: P＝aND₁＋bND₂＋cND₃＋d, 其中a, b, c, d为常数. 用该式对85种链烷烃的标准生成焓Δ_fH^ө_m, 标准熵Δ_fS^ө_m, 标准生成吉布斯自由能Δ_fG^ө_m及67种链烷烃的摩尔体积V_m, 摩尔折射度R_m进行预测, 预测值与实验值吻合良好.     

直链饱和一元胺物理性质递变规律研究

以直链饱和一元胺同系物结构重复单元数值连续变化为模型假定 ,获得了描述直链饱和一元胺同系物物理性质递变规律的数学表达式 :P =a +bnc,其中a、b、c均为常数 ,n为结构重复单元数值 ,P为直链饱和一元胺同系物的物理性质 .通过非线性回归分析 ,得到回归方程 ,结果表明直链饱和一元胺同系物的物理性质与重复单元数值之间满足上述关系式 ,均显示优良的相关性     

有机同系物的指数型同系线性规律（Ⅱ）──共轭多烯链状化合物电子光谱的验证

用共轭多烯链状化合物电子光谱的数据,对指数型同系线性规律进行验证。结果表明指数型同系线性规律具有广泛适用性和较高精确度。在所研究的７１个系列１６９组吸收峰数据中,相关系数属于“优”和“良”的组数总和占总数的９９％以上。     

Computer search for energy-consuming organic compounds with desired physicochemical parameters

A new method for computer searching for energy-consuming organic compounds (EOC) with desired physicochemical properties has been developed. The method is based on a specific multilevel system of efficient parametec and quasi-structural selection criteria specially oriented to the search for EOC. This method makes it possible to perform the search in the area of practically significant empirical formulae (not less than 15 atoms).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2168–2176, September, 1996.     

Recurrent equations of physicochemical constants for homologs substantiated with numerical sequences

The applicability of the unified first order recurrent equations A(n + 1) = aA(n) + b to the approximation of the physicochemical constants of various organic compounds (not only members of homologous series), previously found for normal boiling points, was extended to the dielectric constant (ε). This tendency is equivalent to the general procedure for calculating the ε of any compound from the data for preceding homologs with an accuracy comparable to the average interlaboratory reproducibility of the results of ε measurements. To substantiate this universal character of recurrent relations we consider the analogy between the constants of successive homologs and the recursive numerical sequences (Fibonacci and Padovan sequences versus Lucas and Perrin sequences, respectively).     

Evaluation of a new graphitized carbon black employed in sampling volatile organic compounds

A new adsorbent, high-surface-area graphitized carbon black (HSGCB), with a surface area of 560 m²/g, superior to that of commonly traded graphitized carbons, was studied. The evaluation was performed in terms of breakthrough volumes and thermal desorption recoveries of substances representative of the main classes of organic compounds. HSGCB was found to be an interesting alternative to activated charcoal for volatile compounds in that it can be used in thermal desorption.     

Active nickel-based reduction of organic compounds

The reducing system NiCl₂·2H₂O—Li—arene_cat (cat is catalyst) was proposed for use to reduce a wide range of organic compounds, including alkenes, alkynes, carbonyl compounds, imines, halogenated derivatives, sulfonates, aromatic compounds, hydrazines, azo and azoxy compounds, N-oxides, and nitrones. The degree of reduction can be controlled for some substrates. Deuterium can be incorporated in the reaction products using nickel chloride deuteriohydrate. Nitrones, N-alkoxyamides, and acyl azides are also reduced with the Li—arene_cat system containing no nickel salt.     

二氧化硫脲对有机化合物的还原作用研究

报道了在碱性醇水溶液中，二氧化硫脲对含有硝基、羰基及烯键的有机化合物的还原作用，研究了这些反应的反应条件、反应产物和反应机理。     

System for the generation of standard gas mixtures of volatile and semi-volatile organic compounds for calibrations of solid-phase microextraction and other sampling devices

Standard gases are used for quality control and quality assurance, development of analysis methods and novel air sampling devices. The use of solid-phase microextraction (SPME) and other novel technologies for research in the area of air sampling and analysis requires systems/devices for reliable standard gas generation and sampling. In this paper we describe a new gas standard generating system for volatile organic compounds (VOCs) and semi-VOCs that was designed, built, and tested to facilitate fundamental and applications research with SPME. The system provided for the generation of a wide range of VOC/semi-VOC concentrations and mixing various standard gases, estimation of detection limits, testing the effects of sampling time, air temperature and relative humidity, testing the effects of air velocity and ozone on sampling/extractions. The system can be also used for calibrations of analytical instrumentation, quality control and quality assurance checks, and cross-validations of SPME with/and other sampling techniques.     

Investigations on the peculiar permeation properties of volatile organic compounds and permanent gases through PTMSP

In contrast to common glassy polymers, poly(1-trimethylsilyl-1-propyne) (PTMSP), a high free volume glassy polymer, shows a preferable permeation of large condensable organic vapors in comparison to permanent gases. In order to investigate this phenomenon, a systematic permeability study over a large activity range has been performed on PTMSP with three types of volatile organic compounds (VOCs) as diffusing probes: toluene, dimethylketone and dichloromethane. PTMSP was synthesized with different catalytic systems (Nb or Ta based) able to induce controlled sub-molecular cis–trans structures. Whereas dimethylketone and dichloromethane permeability can be correctly described by a classical dual-mode equation, a peculiar bell shaped pattern was obtained for toluene, with a minimum permeability located at an activity value around a=0.3–0.4. In that case, only a dual-mode expression taking into account a concentration dependent diffusion coefficient can account for the results.

On the other hand some apparent conflicting data recorded from PTMSP brand new films were related to the microstructure of the polymer main chain thanks to ¹³C NMR spectroscopy analysis showing importance of cis- and trans-forms of the main chain of PTMSP. cis-Structure is more flexible and can be responsible for the creation of a higher density physical network (HDN) in polymeric matrix; conversely, trans-structure is more rigid and can provide lower density physical network (LDN). The higher permeability recorded for several probes through PTMSP synthesized with TaCl₅/Al(i-Bu)₃ catalytic system compared to those of NbCl₅ based polymer can be explained by the geometric difference of the macromolecule networks.     

Isolation and preconcentration of volatile organic compounds from water

Methods for the isolation and/or concentration of volatile organic compounds from water samples for trace organic analysis by gas chromatography are reviewed. The following basic groups of methods are discussed: liquid-liquid extraction, adsorption on solid sorbents, extraction with gas (gas stripping and static and dynamic headspace techniques) and membrane processes. The theoretical bases of these methods are discussed. Experimental arrangements for the isolation and/or concentration of volatile compounds from water are presented and discussed with respect to their efficiency. The applicability of the described methods to the isolation and/or concentration of various organic compounds from waters of various origins is discussed.