Binary Solid–Liquid Phase Diagram of Phenol and t-Butanol: An Undergraduate Physical Chemistry Experiment

Abstract

The determination of the solid–liquid phase diagram of a binary system is always used as an experiment in the undergraduate physical chemistry laboratory courses. However, most phase diagrams investigated in the lab are simple eutectic ones, despite the fact that complex binary solid–liquid phase diagrams are more common. In this article, the cooling curves of phenol–t-butanol mixtures are measured and the phase diagram of this system is found to give three eutectic points and two congruent melting points. The laboratory provides the students a practical way to investigate a complex system with their own efforts and teamwork spirit.

Probing the Heterogeneity of Ionic Liquids in Solution through Phenol‐Water Phase Behavior.

“…The hydrogen‐bonded complexes of phenol are examples of interaction with aromatic acid, serving as a prototype for tyrosine residues in proteins interacting with water. Studies of phase behaviour can practically be simulated which helps us to understand the abnormal behaviour of the system, reflected clearly in its phase diagram . Any change in the interaction between two components shows a variation in its phase behaviour .…”

Liquid Crystal Demonstration of Binary Phase Behavior for the Classroom

“…These diagrams are crucial tools for describing the complex phase behavior of technologically significant materials and for illustrating the inter-relationship between material structure, properties, and processing. Students often struggle to accurately interpret binary phase diagrams due to misunderstandings of fundamental concepts, such as solubility and saturation, the nature of different solid phases (e.g., α and β in a simple binary eutectic phase diagram), and the difference between phase fraction and composition. − To address some of these challenges, educators have developed laboratory experiments and demonstrations that allow students to explore binary solid–liquid phase behavior, − partial miscibility in binary liquid systems, and phase transitions in single-component thermotropic liquid crystalline systems. − These experiments and demonstrations can be difficult to conduct in a traditional classroom environment, however, due to the nature of the equipment and chemicals required. Here, a demonstration is described using lyotropic liquid crystals, which have been largely unexplored as an educational tool, that enables students to observe binary phase formation and transformations directly in the classroom.…”

How Is the Freezing Point of a Binary Mixture of Liquids Related to the Composition? A Guided Inquiry Experiment

“…Numerous solid–liquid phase diagram experiments have been published. , Some of the earliest experiments focus on the lead–tin diagram, while more recently published experiments use organic mixtures for the phase diagram. , At least 15 different mixtures could be formed from six different organic compounds; the mixtures form eutectics in experimentally accessible temperature ranges, and the compounds are reasonably priced, available, and safe. Previous work has emphasized the variety of experimental techniques used to measure cooling or heating curves, including differential scanning calorimetry, polarizable microscopy, commercial instrumentation, and the use of spreadsheets to generate the phase diagram. The objective of most of these verification experiments is to generate the phase diagram and determine the enthalpies of fusion for the two compounds in the mixture as a way to demonstrate the thermodynamics equations associated with solid–liquid mixtures.…”

“…Melts of hydroquinone and bis-­[ N , N -diethyl]-­terephthalamide form a third compound, giving rise to two eutectics in this mixture, which is used to introduce students to the topics of molecular recognition and self-assembly. Two intermediate compounds form in mixtures of phenol and t-butanol, and scientists disagree over the specifics of the formation. The phase diagram experiment involving this mixture is used to give students a more researchlike, open-ended experience.…”