Fundamentals of co-crystallization of polyoxacyclobutane and water

聚氧杂环丁烷和水共结晶的基本原理

• 批准号: 1933037
• 负责人: Sachin Velankar
• 金额: $ 35.27万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1933037&HistoricalAwards=false
• 关键词: Fundamentals; co; crystallization; polyoxacyclobutane; water

Crystals composed of two distinct molecules organized within a lattice (co-crystals) are variously known as clathrates, host-guest compounds, intermetallic compounds amongst metals, or hydrates if water is included. A well-known example of an organic co-crystal is the gas hydrate formed from the co-crystallization of methane and water. The co-crystallization of polymers, very long chain organic molecules, with small molecules is unusual, and those with water are especially rare. The focus of this research project is to study a rare class of co-crystals based on the polymer, polyoxacyclobutane (POCB), and water. The researchers will investigate the types of phases that POCB hydrate can form as well as the rates of formation. Understanding the unique behavior of POCB hydrate is important, because it could be applied to a thermal desalination process that involves no membranes. The project will involve training graduate and undergraduate students in state-of-the-art research, as well as some curriculum development related to the topic of the project. The researchers will also perform outreach activities to pre-college students around the topic of molecular shapes and intermolecular interactions, especially in the context of gas hydrates and their relevance to energy. POCB can co-crystallize with water to form a hydrate, which melts upon heating above 37 degrees Celsius. Melting yields either a homogeneous liquid phase, or a water-rich and a polymer-rich two-phase mixture. The properties of the POCB hydrate are unique: (1) the melting point of the co-crystal exceeds that of the two pure species; (2) co-crystallization can occur either from a liquid-liquid equilibrium (LLE) state or from a homogeneous liquid solution; (3) the hydrate is highly insensitive to salt; and (4) the hydrate melting point fortuitously happens to be almost exactly at human body temperature. This combination of properties makes POCB unique not just amongst polymers, but amongst all materials. Very little is known about the POCB hydrate. Even the most basic information, such as the melting point of the hydrate in the high molecular weight limit or its heat of fusion, is missing. This research project will explore the thermodynamics and crystallization kinetics of POCB hydrate and examine the coupling between LLE and crystallization in which the polymer co-crystallizes with the solvent. The unique phase behavior of POCB could be used for a purely-thermal desalination process that requires no vacuum or pressure, no refrigeration, and no membrane. Such a process may enable waste-heat-based desalination and the desalination of high salinity waters. This research project will provide the first proof-of-principle and a preliminary technoeconomic evaluation of such a process.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

由在晶格内组织的两个不同分子组成的晶体（共晶体）被各种地称为笼形物、主-客体化合物、金属间的金属间化合物或水合物（如果包括水）。 有机共晶体的一个众所周知的例子是由甲烷和水的共结晶形成的气体水合物。 聚合物（非常长的有机分子链）与小分子的共结晶是不寻常的，与水的共结晶尤其罕见。该研究项目的重点是研究一类罕见的基于聚合物聚氧杂环丁烷（POCB）和水的共晶。 研究人员将研究POCB水合物可以形成的相的类型以及形成的速率。了解POCB水合物的独特行为很重要，因为它可以应用于不涉及膜的热脱盐过程。 该项目将涉及培训研究生和本科生进行最先进的研究，以及与项目主题有关的一些课程开发。 研究人员还将围绕分子形状和分子间相互作用的主题，特别是在天然气水合物及其与能源的相关性的背景下，为大学预科学生开展外展活动。POCB可以与水共结晶形成水合物，在加热到37摄氏度以上时熔化。 熔融产生均匀的液相，或富水和富聚合物的两相混合物。POCB水合物的性质是独特的：（1）共晶体的熔点超过两种纯物质的熔点;（2）共结晶可以从液-液平衡（LLE）状态或从均匀的液体溶液中发生;（3）水合物对盐高度不敏感;（4）水合物熔点碰巧几乎正好在人体温度。这种特性的组合使得POCB不仅在聚合物中，而且在所有材料中都是独一无二的。对POCB水合物知之甚少。甚至最基本的信息，如水合物在高分子量极限下的熔点或其熔化热，都缺失了。本研究将探讨POCB水合物的热力学和结晶动力学，并研究LLE和结晶之间的耦合，其中聚合物与溶剂共结晶。POCB的独特相行为可用于不需要真空或压力、不需要制冷和不需要膜的纯热脱盐过程。这种方法可以实现基于废热的脱盐和高盐度沃茨的脱盐。这个研究项目将提供第一个原理证明和初步的技术经济评估这样一个过程。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

项目成果

Liquids that Freeze when Mixed: Homogeneous Cocrystallization Kinetics of Polyoxacyclobutane–Water Hydrate

• DOI: 10.1021/acsapm.1c01626
• 发表时间: 2021-12
• 期刊: ACS Applied Polymer Materials
• 影响因子: 5
• 作者: Emily F. Barker;S. Banerjee;T. Meyer;S. Velankar

Polymer co-crystallization from LLE: Crystallization kinetics of POCB hydrate from two-phase mixtures of POCB and water

LLE 中的聚合物共结晶：POCB 水合物从 POCB 和水的两相混合物中的结晶动力学

• DOI: 10.1016/j.polymer.2023.126087
• 发表时间: 2023
• 期刊: Polymer
• 影响因子: 4.6
• 作者: Banerjee, Sudesna;Gresh-Sill, Michael;Barker, Emily F.;Meyer, Tara Y.;Velankar, Sachin S.
• 通讯作者: Velankar, Sachin S.

Salt Effects on the Phase Behavior and Cocrystallization Kinetics of POCB–Water Mixtures

盐对 POCB-水混合物的相行为和共结晶动力学的影响

• 发表时间: 2024
• 期刊: Langmuir
• 影响因子: 3.9
• 作者: Michael Gresh;Sudesna Banerjee;Tara Y Meyer;Sachin S Velankar
• 通讯作者: Sachin S Velankar