Novel Process Applications Using PHI-TEC II Adiabatic Calorimeter

This paper presents several applications of the PHI-TEC II that are not commonly associated with adiabatic calorimeters but which have proved to be extremely valuable. These include simulation of a deep oil well for enhanced oil recovery, isothermal calorimetry of a semibatch reaction, catalyst research using flow through reactors (both plug flow and CSTR) with controlled feeds of high pressure liquid and gas.This revised version was published online in November 2005 with corrections to the Cover Date.     

Comparing Methods for Calculating the Heat Flow Rate of Reactions in Different Bench-Scale Calorimeters

Summary: A transfer function of the RC1e™ (Mettler-Toledo) calorimeter was obtained by calibration with a heating cartridge. With this function it was possible to determine the heat flow rate and total heat of different polymerization reactions. The calorimeter operates in isothermal as well as in isoperibolic mode. Additionally, 1-vinyl-2-pyrrolidone and acrylic acid were polymerized in a three-neck flask. In this common laboratory device the heat flow rate was obtained by using a transfer function calculated by calibration with a heating cartridge. Thus, the heat of polymerization can be obtained without using a calorimeter and without solving the heat balance equation.     

The Synthesis of Special Block Copolymers Using a Reaction Calorimeter

Summary : The paper provides experimental results about an easy and versatile method to produce amphiphilic block copolymers, block copolymer particles, and even inorganic – polymeric nano-composites via aqueous heterophase polymerization. Special emphasis is placed on the morphology and colloidal properties of some non-ionic di- and triblock copolymer particles with poly(ethylene glycol) of 10⁶ g/mol molecular weight as hydrophilic block as well as di-stimuli-responsive block copolymers containing both a poly(N-isopropyl acrylamide) and a poly(ionic liquid) block.     

Changes in the Transfer Function of a flow microcalorimeter

Flow microcalorimeters are used to determine thermodynamic properties of liquid mixtures, the accuracy of these measures depends on the right calibration of the instrument. In this work the system is identified by means of the transfer functions of the two poles, it is proven that the first time constant and the sensitivity change with the value of rc _p f of the injected liquids (r - density, c _p - heat capacity, f - injection flow), and that the sensitivities obtained in the electrical and chemical calibrations are different for the same value of rc _p f because the dissipation in each case does not occur in the same place. As a summary of the calibration carried out, it is proposed a sensitivity value of 313±4 mV W^-1 for rc _p f<15 mW K^-1 that permits to make thermal measures with an uncertainty of 3%. This revised version was published online in July 2006 with corrections to the Cover Date.     

On-line Calibration and Determination of the Heat of Reaction for Laboratory Scale Heat Transfer Calorimeters

A simple method for the on-line calibration, in which both the heat transfer coefficient and the heat capacity of the reactor contents are determined, is described for laboratory scale heat transfer calorimeters. The calorimeter is operated in the isoperibolic mode for the calibration and a constant power is supplied to a resistor placed inside the reactor. The reactor heat balance differential equation is used to produce a set of linear simultaneous equations with each data acquisition cycle giving one equation. The heat transfer coefficient and the heat capacity are obtained from this set of equations by linear least squares. The application of the calibration procedure is illustrated by experiments in which the heat of reaction is determined on-line fora simulated reaction with first order kinetics and for the hydrolysis of acetic anhydride. This revised version was published online in July 2006 with corrections to the Cover Date.     

Theoretical Study on the Kinetics of Electron Transfer for Bond—breaking Reaction

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荷移反应用于氨苄青霉素的测定

研究了氨苄青霉素与对苯醌的荷移反应，确定了反应条件。在ＰＨ４．４－５．０的醋酸－醋酸钠缓冲溶液中形成１：１络合物，其λｍａｘ＝４７２ｎｍ。氨苄青霉素三水合物浓度在１０－１２５ｍｇ／Ｌ范围地线性关系；当浓度为５０ｍｇ／Ｌ时相对标准偏１．８％；表观摩尔吸光系数为２．６４×１０＾３Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。应用拟定的方法测定药物制剂含量，结果与药典方法一致。回收率在９６％以上。     

Barrier Compression Enhances an Enzymatic Hydrogen‐Transfer Reaction

Putting the squeeze on : Hydrostatic pressure causes a shortening of the charge‐transfer bond in the binary complex of morphinone reductase and NADH₄ (see diagram). Molecular dynamics simulations suggest that pressure reduces the average reaction barrier width by restricting the conformational space available to the flavin mononucleotide and NADH within the active site. The apparent rate of catalysis increases with pressure.

     

氧氟沙星与四氰基乙烯的荷移反应研究

研究了氧氟沙星与四氰基乙烯 (TCNE)的荷移反应 ,确立了形成电荷转移 (CT)络合物的最佳条件。在丙酮介质中 ,于 50℃水浴中恒温 30 min即可形成 1∶ 1络合物 ,其最大吸收波长为 40 9nm。表观摩尔吸光系数 ε为 2 .8× 1 0 4 L· mol- 1· cm- 1。在 0～ 1 2 μg· m L- 1范围内符合比耳定律。方法的相对标准偏差小于 1 %。对形成 CT络合物的机理进行了探讨。用拟定的方法对样品氧氟沙星药片进行测定 ,结果与紫外分光光度法一致 ,回收率符合要求     

阿苯达唑与氯冉酸的荷移反应与应用

研究并确定了阿苯达唑与氯冉酸的荷移反应条件。在乙醇丙酮介质中形成１∶１络合物,其λｍａｘ＝５２５　ｎｍ,吸光度与阿苯达唑浓度在０～２８０　ｍｇ／Ｌ范围内呈线性关系;表观摩尔吸光系数为８．０３×１０３Ｌ·ｍｏｌ－１·ｃｍ－１;桑德尔灵敏度为０．０３３　μｇ·ｃｍ－２;相对标准偏差小于１％（ｎ＝８）,回收率符合要求。     

A Conduction Calorimeter for Measuring the Heat of Cement Hydration in the Initial Hydration Period

A new-design conduction microcalorimeter is described, which has been used to measure the heat of cement hydration evolved in the initial period of hydration. The calorimeter is 30 cm³ in volume; the heat loss coefficient is 27.270±0.015 W V^–1, the time constant is 300 s. This revised version was published online in July 2006 with corrections to the Cover Date.     

荷移反应用于测定烟胺羟丙茶碱

烟胺羟丙茶碱与茜素红在水溶液中发生电行转移反应，生成2：1型络合物，此络合物的λmax=539nm，表观摩尔吸光系数是2．72×103L·mol－1·cm-1，药物浓度在5－150mg／L范围内符合比尔定律，相对标准偏差为0．81％（n=6），回收率在97％以上。应用拟定的方法测定药物制剂的含量，结果与紫外分光光度法一致。     

盐酸芦氟沙星荷移反应及荧光光谱性质

研究了盐酸芦氟沙星(RH)与电子受体四氟苯醌(TFQ)及四氯苯醌(TCQ)之间的荷移反应。实验表明：在甲醇体系中,RH与TFQ可迅速反应生成稳定的荷移络合物,最大激发波长和发射波长较RH向长波方向分别位移122nm和205nm;荧光强度较RH增强13倍。研究了各种溶剂对络合物形成的影响,并探讨了发光机理。在0．1—30μmoL／L浓度范围内,RH与TFQ形成的络合物荧光强度与浓度呈良好线性关系,检出限为0．017μmol／L。该体系的抗干扰能力及稳定性较好。本方法用于胶囊中盐酸芦氟沙星含量的测定,RSD为0．41％：回收率为97．1％-101．9％,结果满意。     

左旋多巴荷移反应及其光谱性质研究

研究了发生在左旋多巴与电子受体四氯对苯醌(TCBQ)之间的荷移反应。实验结果表明,左旋多巴与四氯对苯醌在硼砂缓冲液中可生成稳定的1∶1型络合物,其λmax=348 nm,表观摩尔吸光系数ε=6.2×103L.mol-1.cm-1,左旋多巴在0~26.4μg/mL范围内与分析信号呈线性关系。回收率为98.03%~100.3%,相对标准偏差在2.3%以内。应用本法测定了左旋多巴片剂的含量,结果与文献方法一致。     

A Novel Estimation Method of the Distribution of Carboxyl Groups Within Copolymer Particles Using Isothermal Titration Calorimeter

Summary: A novel quantitative method using isothermal titration calorimeter (ITC) for the estimation of the distribution of carboxyl groups within polymer particles has been proposed. The method has been employed to clarify the difference in the distribution between the particles prepared by batch emulsion copolymerization of styrene and methacrylic acid under inefficient and efficient stirring conditions. At inefficient stirring, monomer was floating as a layer on the aqueous medium, whereas at efficient stirring, the monomer phase was dispersed as droplets. Under inefficient stirring, methacrylic acid (MAA) polymerized faster than styrene (S) due to a slower diffusion rate of S than MAA into the aqueous medium, while under efficient stirring, S and MAA copolymerized at similar rates. ITC measurement showed that under inefficient stirring, the carboxyl groups were distributed mainly in the center of the particles, and their number decreased toward the surface. On the other hand, under efficient stirring, carboxyl groups were distributed homogeneously inside the particle.     

罗红霉素与紫色素的荷移反应及其测定

建立了一种测定罗红霉素的方便而快捷的荷移分光光度法。罗红霉素与紫色素在乙醇介质中发生电荷转移反应 ,荷移络合物在 5 4 4nm处有最大吸收 ;表观摩尔吸光系数是 6 .5 6× 10 3L·mol- 1 ·cm- 1 ,该络合物的组成是 1∶1,稳定常数是 3× 10 4 。药物浓度在 0～ 12 0mg L范围内服从比耳定律。当罗红霉素浓度为 5 0mg L时 ,5次测定结果的相对标准偏差为 1.3%。利用本法测定了罗红霉素胶囊中有效成分的含量 ,并与文献法进行比较 ,二者结果基本吻合 ,回收率在 96 %以上。     

克拉霉素与紫色素的荷移反应及其测定

建立了一种测定克拉霉素的荷移分光光度法。克拉霉素与紫色素在乙醇溶液中发生电荷转移反应,荷移络合物在548nm处有最大吸收,表观摩尔吸光系数是4.49×103L·mol-1·cm-1,该络合物的组成是1∶1;稳定常数是3.48×104;药物浓度在10~150mg/L范围内服从比耳定律。当克拉霉素浓度为100mg/L时,6次测定结果的相对标准偏差为1.2%。利用本法测定了克拉霉素制剂中有效成分的含量,并与文献法进行比较,二者结果基本吻合,回收率在97.0%以上。     

Nd(Gly)2Cl3·3H2O和Pr(Ala)3Cl3·3H2O的热力学性质

利用精密自动绝热热量计测定了Nd(Gly)₂Cl₃·3H₂O在80-357K和Pr(Ala)₃Cl₃·3H₂O在80-374K温区的热容. 根据两个化合物的热容计算出了相对于参考温度298.15K的热力学函数(H_T?H_298.15)和(S_T?S_298.15). 根据热重(TG)分析结果, 提出了这两个稀土化合物可能的热分解机理. 利用溶解-反应恒温热量计测定相关化合物的溶解焓并设计盖斯热化学循环, 计算出了两个化合物的标准摩尔生成焓.     

阿奇霉素与茜素的电荷转移反应及其测定

建立了一种快速测定阿奇霉素的荷移分光光度法。阿奇霉素与茜素在乙醇介质中发生电荷转移反应 ,电荷转移络合物在 5 4 6nm处有最大吸收 ,表观摩尔吸光系数为 5 .79× 10 3 L·mol-1·cm-1;该络合物的组成是 1∶1;稳定常数为 4 .8× 10 3 ;药物浓度在 5～ 12 0mg/L范围内服从比耳定律。利用本法测定了阿奇霉素制剂中有效成分的含量 ,并与文献法进行比较 ,二者结果基本吻合。