苯中异氰酸苯酯的气相色谱分析

异氰酸苯酯是无色液体,极易溶于乙醚、苯和氯仿,具强折光性和辛辣气味,常用作生产氯吡啶的原料.     

大气及污染源排放气体中苯系物气相色谱测定

建立了气体样品中不同浓度的苯系物的分析方法,优化了测定的操作条件,提出了保证测定质量的技术关键。方法已用于污染源及环境空气中苯系物的气相色谱测定。     

苯系物扩散管气体标准物质的研制

按照ISO 6145—2003、ISO 6144—1998标准,研制了新型气体标准物质动态配气装置,实现了微机对动态配气装置主要参数数据的实时监控。用该装置研制了氮中微量苯系物扩散管气体标准物质,量值的相对扩展不确定度为2％-3％,并与静态容量法配气进行了比较。     

异苯橡胶和环化异苯橡胶结构表征

异苯橡胶和环化异苯橡胶结构表征孙晓日，李大珍，余尚先（山东昌潍师范专科学校化学系山东潍坊２６１０１３）（北京师范大学化学系北京１００８７５）关键词异苯橡胶，环化异苯橡胶，结构异戊二烯与苯乙烯无规共聚或嵌段共聚得到异苯橡胶已有不少研究和报导￣［１，２］...     

苯在固定床反应器内电解制备对苯二醌

苯在固定电化学反应氧制备对苯二醌，阳极和阴极分别为多孔铅合金和铅粒。是解液是１ｍｏｌ／ｌ硫酸水溶液，苯分散于电解液中。最佳电解条件：电解液流速ｕ＝０．１９ｍ．ｓ＾－１，反应器厚度Ｌ＝１０ｍｍ，电极电位Ｅ＝１．６Ｖ，电流Ｉ＝１０Ａ和苯含量ＣＢ＝２４％，电流效率ＣＥ是６２．９％。     

一种检测微量苯的气体检测系统

<正>公开号:CN103439380A公开日:2013.12.11申请人:浙江工商大学摘要本发明涉及检测装置领域,尤其涉及一种检测微量苯的气体检测系统,该系统包括气室,气室内设有气体传感器,气室外设有与气体传感器相连的CHI电化学分析仪以及与气室相连的传感器还原装置、待测气体进气口和尾气处理装置;所述气体传感器包括自上而下依次分布的气体敏感膜、第一电极和第二电极,第二电极由铝板经阳极氧化制备而     

1,4—双（取代苯乙炔基）苯电子光谱的溶剂效应

1,4-双(取代苯乙炔基)苯是较好的荧光物质并有良好的激光转换效率。本文测定了1,4-双(苯乙炔基)苯1和1,4-双[(4-叔丁基苯基)乙炔基]苯2在14种溶剂中的紫外吸收光谱和荧光发射光谱,并用多元回归QSAR程序研究了它们的溶剂效应。 1 实验 UV谱用Beckman DU-8B紫外可见分光光度计测定。荧光光谱在MPF-4荧光仪上测得。     

聚间苯硫醚和聚对苯硫醚的对比表征

聚对苯硫醚[poly(pphenylenesulfide),简称pPPS]的分子链是由对苯撑基和硫原子交替连接构成而使制品抗冲击能力差[1](有些研究者用共聚或共混的方法在pPPS中引入间位结构来达到减少其结晶度,增强韧性的目的)。余自力等[2]用硫磺溶液法合成了mPPS、pPPS及其共聚物,认为在pP...     

The heat capacities and parameters of solid phase transitions and fusion for 1- and 2-adamantanols

The heat capacities of 1-adamantanol and 2-adamantanol in the condensed state were measured in a vacuum adiabatic calorimeter between (5 and 305) K and in a scanning calorimeter of the heat bridge type between (300 and 600) K. It was found that 1-adamantanol formed two different crystalline phases, and 2-adamantanol formed four different crystalline phases. The thermodynamic characteristics of the solid-to-solid phase transitions and fusion were obtained. The thermal functions of the studied compounds in the crystalline and liquid state were obtained. The high-temperature crystalline phases (crI) of both compounds had cubic face-centered lattices that followed from X-ray diffraction data. The lattice parameters were calculated.     

Absolute calibration of flow calorimeters used for measuring differences in heat capacities. A chemical standard for temperatures between 325 and 600K

Two methods for the absolute calibration of flow calorimeters (used for measuring the differences in heat capacities of two fluids) have been investigated. In the recommended method of calibration, a change in the flow rate of the fluids is used to minic a change in the heat capacity of the fluid. In the other method of calibration, heat loss is measured using a fluid of known heat capacity, and it is assumed this heat loss is constant. This calibration method is not recommended because the heat loss is, in general, not constant. For some calorimeters the difference between the two methods of calibration is negligible, while for others erros as high as 40% are caused by choosing the wrong method. A detailed analysis of the heat losses in this kind of calorimetry shows why the two calibration methods give different results and leads to various methods of improving calorimeter construction and operation. Because chemical standardization is far more convenient for routine use, the recommended absolute calibration method has been used to establish 3.00 mol-kg^–1 aqueous NaCl as a chemical standard for temperatures between 325 and 600K at 17.7 MPa.     

配合物Zn(Phe)(NO3)2·H2O(s)的低温热容和标准摩尔生成焓

利用精密自动绝热热量计直接测定了配合物Zn(Phe)(NO3)2·H2O(s) (Phe:苯丙氨酸)在78-370 K温区的摩尔热容. 通过热容曲线的解析得到该配合物的起始脱水温度为, T0=(324.27±0.37) K. 将该温区的摩尔热容实验值用最小二乘法拟合得到摩尔热容(Cp, m)对温度(T)的多项式方程, 并且在此基础上计算出了它的舒平热容值和各种热力学函数值. 依据Hess定律, 通过设计热化学循环, 选择体积为100 mL浓度为2 mol·L-1 的盐酸作为量热溶剂, 利用等温环境溶解-反应热量计分别测定混合物{ZnSO4·7H2O(s)+2NaNO3(s)+L-Phe(s)}和{Zn(Phe)(NO3)2·H2O(s)+Na2SO4(s)}的溶解焓为, ⊿dH0m,1 =(69.42±0.05) kJ·mol-1, ⊿dH0 m,2 =(48.14±0.04) kJ·mol-1, 进而计算出该配合物的标准摩尔生成焓为, ⊿fH0m =-(1363.10±3.52) kJ·mol-1. 另外, 利用紫外-可见(UV-Vis)光谱和折光指数(refractiveindex)的测量结果检验了所设计的热化学循环的可靠性.     

Thermophysical properties of 1-hexanol over the temperature range from 303 K to 503 K and at pressures from the saturation line to 400 MPa

Isobaric thermal expansivities, _P(T,p), of 1-hexanol have been measured in a pressure-controlled scanning calorimeter from just above the saturation vapour pressure to 400 Mpa at temperatures from 302.6 K to 503.15 K. The specific volume isotherm, v(T_R,p), at T_R=302.6 K has been derived from measurements of isothermal compressibilities up to 400 MPa and from the specific density at atmospheric pressure. Specific volumes, isothermal compressibilities, thermal pressure coefficients, and isobaric and isochoric heat capacities for the whole pressure and temperature range are derived from these data and from literature data on the saturation vapour pressures and on the isobaric heat capacities at atmospheric or saturation vapour pressure.     

Thermodynamic properties of biofuels: Heat capacities of binary mixtures containing ethanol and hydrocarbons up to 20 MPa and the pure compounds using a new flow calorimeter

Heat capacities are of great significance in the design of new processes and the improvement of existing ones in R&D in production plants as well as the adaptation of new products, in this case, biofuels to their use in a variety of engines and technical devices. An automated flow calorimeter has been developed for the accurate measurement of isobaric heat capacities for pure compounds and mixtures over the range (250 to 400) K and (0 to 20) MPa. In this paper, isobaric heat capacities for heptane, ethanol and the binary mixtures of ethanol with heptane and toluene are reported.     

吡啶-2,6-二甲酸氢钾的合成、结构表征及热化学性质

合成了吡啶-2,6-二甲酸氢钾(KHDPC). 利用X射线单晶衍射仪确定了化合物的晶体结构. 用精密自动绝热热量计测量了其在78~360 K温度区间的低温热容. 利用最小二乘法对配合物的实验热容进行拟合, 得到热容随温度变化的多项式方程. 利用此方程计算出温度区间内的舒平热容值及相对于298.15 K时的热力学函数值. 利用Hess定律设计合理的热化学循环, 在等温环境下利用溶解-反应热量计分别测定所设计热化学反应的反应物和产物在所选溶剂中的溶解焓并计算出反应的反应焓. 最后, 计算出该化合物的标准摩尔生成焓为-(1052.69±1.52) kJ/mol.     

A Low-temperature Automated Adiabatic Calorimeter Heat Capacities of High-purity Graphite and Polystyrene

A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed. The sample cell of the calorimeter, which is about 50 cm³ in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller. The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al₂O₃. The results agreed well with those of the National Bureau of Standards (NBS): within ±0.2% throughout the whole temperature region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using the above-mentioned calorimeter. The results were tabulated and plotted and the thermal behavior of the two materials was discussed in detail. Polynomial expressions for calculation of the heat capacities of the two substances are presented. This revised version was published online in August 2006 with corrections to the Cover Date.     

Conformational contribution to the heat capacity of the starch and water system

The heat capacities of starch and starch—water have been measured with adiabatic calorimetry and standard differential scanning calorimetry and are reported from 8 to 490 K. The amorphous starch containing 11–26 wt % (53–76 mol %) water shows a partial glass transition decreasing from 372 to 270 K, respectively. Even the dry amorphous starch gradually increases in heat capacity above 270 K beyond that set by the vibrational density of states. This gradual increase in the heat capacity is identified as part of the glass transition of dry starch that is, however, not completed at the decomposition temperature. The heat capacities of the glassy, dry starch are linked to an approximate group vibrational spectrum with 44 degrees of freedom. The Tarasov equation is used to estimate the heat capacity contribution due to skeletal vibrations with the parameters Θ₁ = 795.5 K, Θ₂ = 159 K, and Θ₃ = 58 K for 19 degrees of freedom. The calculated and experimental heat capacities agree better than ±3% between 8 and 250 K. Similarly, the vibrational heat capacity has been estimated for glassy water by being linked to an approximate group vibrational spectrum and the Tarasov equation (Θ₁ = 1105.5 K and Θ₃ = 72.4 K, with 6 degrees of freedom). Below the glass transition, the heat capacity of the solid starch—water system has been estimated from the appropriate sum of its components and also from a direct fitting to skeletal vibrations. Above the glass transition, the differences are interpreted as contributions of different conformational heat capacities from chains of the carbohydrates interacting with water. The conformational parts are estimated from the experimental heat capacities of dry starch and starch—water, decreased by the vibrational and external contributions to the heat capacity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 3038–3054, 2001     

配合物Zn(Met)SO4•H2O(s)的低温热容和标准摩尔生成焓

利用精密自动绝热热量计直接测定了配合物Zn(Met)SO₄•H₂O(s) 在78～370 K温区的摩尔热容. 通过热容曲线的解析得到该配合物的起始脱水温度为T₀＝329.50 K. 将该温区的摩尔热容实验值用最小二乘法拟合得到摩尔热容 (C_p,m)对温度(T)的多项式方程, 并且在此基础上计算出了它的舒平热容值和各种热力学函数值. 依据Hess定律, 通过设计热化学循环, 选择体积为100 cm³、浓度为2 mol•L^－1的盐酸作为量热溶剂, 利用等温环境溶解-反应热量计, 测定和推算出该配合物的标准摩尔生成焓为Δ_fH_m⁰＝－(2069.30±0.74) kJ•mol^－1.     

Heat capacity of molten polymers

Heat capacities of molten polyethylene, polypropylene, poly-1-butene, polystyrene, and poly(methyl methacrylate) were measured over a wide range of temperature by using a differential scanning calorimeter. The upper limit of temperature was established for each polymer at about 10°K below the beginning of thermal decomposition. For poly-1-butene and poly(methyl methacrylate) the solid-state heat capacity was also measured starting from room temperature. Several samples of each polymer were used so that average values of heat capacities could be established (reported in 10°K intervals). The data revealed for all polymers a nearly linear increase of heat capacity with increasing temperature over the whole temperature range investigated.