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. 相似文献
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. 相似文献
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. 相似文献
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 rcpf of the injected liquids (r - density, cp - heat capacity, f - injection flow), and that the sensitivities obtained in the electrical and chemical calibrations are different for the
same value of rcpf 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 rcpf<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. 相似文献
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. 相似文献
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.
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. 相似文献
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. 相似文献