Chiral Purification of S-2-Phenylpropionic Acid from an Enantiomer Mixture by Stripping Crystallization

Abstract

Stripping crystallization (SC) was applied in this study to purify S-2-phenylpropionic acid (S-2-PPA) from enantiomer mixtures. According to the solid–liquid equilibrium predicted by the Schroder–Van Laar equation and the vapor–liquid equilibrium predicted by Raoult’s law, a series of three-phase transformation conditions were determined to perform the batch SC experiments. As opposed to the solid–liquid transformation in melt crystallization, a series of three-phase transformations occur operated at low pressures during the SC cooling process. The experimental yield and purity for the final S-2-PPA product obtained during SC were investigated. A comparison was made between the experimental results and the calculated results based on the material and energy balances.

Purification of p-Cresol, o-Cresol, m-Cresol, and 2,6-Xylenol from the Quaternary Mixture by Three-Phase Crystallization

“…A model based on the thermodynamics coupled with the mass and energy balances was proposed to describe the TPC process for the quaternary system, which differs from the previous model developed for the binary system . The PC process starts with a liquid mixture.…”

“…A model based on the thermodynamics coupled with the mass and energy balances was proposed to describe the TPC process for the quaternary system, which differs from the previous model developed for the binary system. 31 The PC process starts with a liquid mixture. As the three-phase transformation occurs in the liquid mixture in each stage, the solid−liquid equilibrium between the component-1 crystalline product and liquid mixture in stage n (n = 1, 2, ..., N) can be described by the van't Hoff equation as 53,54 i k j j j j j y…”

“…Three-phase crystallization (TPC), also known as stripping crystallization, was initially introduced by Shiau and his co-workers to separate mixed xylenes with close boiling temperatures. − Later, they applied TPC to separate chiral mixtures with the same boiling temperatures. − Basically, TPC combines melt crystallization and vaporization. Melt crystallization has long been adopted to obtain the desired crystalline solid from a liquid mixture via the solid–liquid transformation due to cooling at normal pressure. − TPC resembles melt crystallization operated at reduced pressure during the cooling process, leading to the formation of a crystalline product along with a vapor mixture from the liquid mixture via a series of three-phase transformations.…”

Chiral Purification of S‐Methyl‐2‐chloropropionate from Enantiomer Mixtures by Three‐Phase Crystallization

“…Three-phase crystallization (TPC), also known as stripping crystallization, was initially introduced by Shiau and his coworkers to separate the mixed xylenes with the close boiling temperatures [1][2][3][4][5]. Recently, TPC has been applied by Shiau and his co-workers to separate the enantiomer mixtures for chiral compounds [6][7][8]. Basically, TPC is a new separation technology, which combines melt crystallization and vaporization.…”

“…For melt crystallization, the desired crystalline solid is formed from a liquid mixture via the solid-liquid transformation occurred at normal pressure during the cooling process [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. TPC resembles melt crystallization operated at reduced pressure during the cooling process, leading to the formation of desired crystalline solid along with vapor mixture from a liquid mixture via a series of three-phase transformations [1][2][3][4][5][6][7][8]. The vapor mixture can be removed and collected and, subsequently, no crystal/liquid separation is required after TPC if no liquid is remained along with the final crystalline solid at the end of TPC.…”