AUTHOR=Liu Weiping , Zhou Yu , Xu Xianzhen 

TITLE=Study on vapor–liquid equilibrium and microscopic properties of DL-proline, L-glutamic acid, and L-serine aqueous solutions

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1005291

DOI=10.3389/fchem.2022.1005291

ISSN=2296-2646

ABSTRACT=<p>The vapor–liquid equilibrium (VLE) in aqueous amino acid solutions is essential in chemical production, such as purification, isolation, or crystallization of amino acid intermediates. In this work, VLE of <sc>DL</sc>-proline, <sc>L</sc>-glutamic acid, and <sc>L</sc>-serine aqueous solutions was measured at pressures ranging from 4.82 to 102.58 kPa. The developed model was successfully applied to correlate experimental data with temperatures in the range of 298.15–382.75 K. Model parameters (<italic>h</italic>, <inline-formula id="inf1"><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow><mml:mi>w</mml:mi><mml:mo>,</mml:mo><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula>, <inline-formula id="inf2"><mml:math id="m2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow><mml:mi>w</mml:mi><mml:mo>,</mml:mo><mml:mi>i</mml:mi></mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula>, <inline-formula id="inf3"><mml:math id="m3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow><mml:mi>i</mml:mi><mml:mo>,</mml:mo><mml:mi>w</mml:mi></mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula>, and <inline-formula id="inf4"><mml:math id="m4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi>τ</mml:mi><mml:mrow><mml:mi>i</mml:mi><mml:mo>,</mml:mo><mml:mi>w</mml:mi></mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mn>1</mml:mn></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula> ) were given. Moreover, the amino acid aqueous solution was investigated by Fourier transform infrared spectroscopy (FTIR). By analyzing infrared spectra, the strength of intermolecular interactions was obtained, and the structure–activity relationship between the microscopic interactions and the VLE was established.</p>