Development of New Derivatization Method By Use of Supercritical Fluid

1997 Fiscal Year Final Research Report Summary

• Project/Area Number: 08650963
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 工業分析化学
• Research Institution: TOYOHASHI UNIVERSITY OF TECHNOLOGY
• Principal Investigator: HIRATA Yukio Toyohashi University of Technology, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10126948)
• Project Period (FY): 1996 – 1997
• Keywords: supercritical fluid / carboxylic acids / methylation / depolymerization

Research Abstract

Supercritical fluid is the substance of state above the critical temperature and the critical pressure, and has the liquid-like density and the high diffusion coefficient which is in the middle of those of gas and liquid. The use of this fluid as the reaction solvent may dramatically accelerate the reaction rate compared to the conventional liquid solvent, resulting in significant reduction of the reaction time. Since supercritical fluid varies its properties by changing the pressure and the temperature, it is easy to control the reaction conditions. The purpose of this project is to develop new derivatization method by use of supercritical fluids.
1. Methylation of carboxylic acids in supercritical carbon dioxide modified with methanol was studied using a flow-through system. Using strong cation-exchanger with H form as catalyst allowed the complete conversion under mild conditions. Parameters, such as temperature, pressure and methanol concentration, were optimized taking account of the rapidity. Applicability of this method combined with solid phase extraction was demonstrated for the analysis of phenoxyacetic acids in water.
2. Polyesters such as polyethylene terephthalate, polybutylene terephthalate and liquid crystalline aromatic polyester and polycarbonate were depolymerized in supercritical methanol. The fundamental conditions were investigated with respect to the time, pressure and temperature for the depolymerization. All polyesters and polycarbaonate were converted to their corresponding monomers quantitatively within 30 minutes at the pressure of 100 atm. Only 1 mg as sample weight was required for this experiment. The optimum temperature for the depolymerization was 275ﾟC.At the lower temperature the oligomers were also generated and at the higher temperature aromatic hydroxyl groups were converted to methoxy group or methyl carbonate group.