Guest-dependent physicochemical properties of clathrate hydrates and their applications to functionalized energy materials

Abstract

Clathrate hydrate is one type of inclusion compounds which is composed of host water framework that can accommodate several types of guest molecules such as small gas and organic molecules. In this thesis, there are four chapters dealing with the intracavity conformational change of guest species, the thermodynamic and kinetic study of binary clathrate hydrates, and the application to functionalized hydrogen storage materials. The detailed comments are shown below. Chapter 2 firstly reports the conformational change of acyclic guest molecule (methyl vinyl ketone) occurring in the hydrate cavities. This unique phenomenon depends on the types of secondary guest molecules. Chapter 3 focuses on the two clathrate hydrate former of methacrolein and 3-hydroxytetrahydrofuran having promotion and inhibition effect, respectively. The phase equilibria of binary $(former + CH_4, N_2, O_2, and CO_2)$ clathrate hydrates are also presented. Chapter 4 focuses on the kinetic study of binary clathrate hydrate with a new perspective of Mpemba effect and suggests a novel strategy for rapid hydrate formation using iodomethane and surfactant (sodium dodecyl sulfate). Lastly, chapter 5 introduces a new concept of using hydrocarbon mixture for tuning the hydrate cage to achieve both multiple and double hydrogen occupancy in large and small cages at the same time.