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Pressure-Temperature Phase Diagram Of Tris (Hydroxymethyl)Aminomethane And Phase Diagram Determination Of Tris(Hydroxymethyl)Aminomethane -- 2-Amino-2-Methyl-1, 3-Propanediol(AMPL) Binary System
Date
2010Type
ThesisDepartment
Chemical and Materials Engineering
Degree Level
Master's Degree
Abstract
A pressure-temperature phase diagram of the
tris (hydroxymethyl) aminomethane(TRIS) and a temperature-composition equilibrium
phase diagram of the tris(hydroxymethyl) aminomethane(TRIS) -- 2-Amino-2methyl-1,3-
propanediol(AMPL) binary system are developed. The component organic crystalline
materials undergo solid-solid phase transitions and their property make them suitable for
storage of thermal energy. The low temperature crystal structure of pure TRIS is
orthorhombic, and that of the pure AMPL is monoclinic.
In this study, Raman spectroscopy was performed at different temperatures and
pressures to determine structural changes in the P-T diagram of TRIS. In situ high pressure/high-temperature Raman spectroscopy experiments were carried out using
resistively heated heated diamond anvil cells up to160 oC and 7 GPa. High pressure
experiments performed at room temperature showed transformation of the orthorhombic
-TRIS to -TRIS phase at ~1.17 GPa. As the temperature is increased to ~130 oC at
ambient pressure, both phases transform to -TRIS. The experiments were also
run at different temperatures and pressures, by which a typical pressure-temperature
phase diagram of TRIS has been developed.
The binary phase diagram of TRIS-AMPL was constructed using the PANalytical
X-ray diffractometer and differential scanning calorimetric data. It was found that below
~75 oC, there is virtually no solubility of AMPL in TRIS or vice versa. The AMPL rich
phase transforms to an AMPL rich phase at ~75 oC. Between ~75 oC and 105 oC a wide
phase region is observed. The maximum solubility of TRIS in AMPL is at ~12% TRIS at 73 oC and that of AMPL in TRIS is 40% AMPL at ~125 oC. The phase diagram
exhibits two eutectoidal transformations at 73 oC and at 108 oC respectively. The phase diagram also exhibits a peritectic transformation at 128 oC. A two phase region with plastic phases rich in TRIS and AMPL is
also observed between 105 oC and 125 oC. Lattice parameters changes with increase in
temperature have also been studied.
Permanent link
http://hdl.handle.net/11714/4368Additional Information
Committee Member | Covington, Aaron; Li, Qizhen; Chien, Wen M. |
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Rights | In Copyright(All Rights Reserved) |
Rights Holder | Author(s) |