Ultrasonic Relaxation for Complexation Reactions between α-Cyclodextrin and Pentanol Isomers in an Aqueous Solution

배종림,Jung Hee Do 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

The aim of this work was to reveal the effect of the hydrophilic part of a guest molecule on the kinetic parameters in an inclusion reaction with α-cyclodextrin. Ultrasonic absorption measurements in the frequency range from 0.2 to 8 MHz were carried out for α-cyclodextrin solutions with pentanol isomers at 25°C by using resonator methods. The rate and the equilibrium constants were obtained from the concentration dependence of the relaxation frequency, and the standard volume changes of the complexation reaction were obtained from the maximum absorption per wavelength. A single relaxational absorption was observed, and the cause of the relaxation was attributed to a perturbation of the chemical equilibrium associated with a complexation reaction between α- cyclodextrin and pentanol isomers. The backward rate constant, kb, depended on the structure of the guest molecules. The value of kb was affected by the stability of host-guest complex, which depended on the position of the hydroxy group. In complex formation between α-cyclodextrin and pentanol isomers, the values of kb increased in the order of nor (kb = 2.23 × 106s−1), sec (kb = 3.46 × 106s−1), and tert (kb = 8.77 × 106s−1). In addition, standard volume changes, V , increased in the order of nor (4.12 × 10−6m3mol−1), sec (4.67 × 10−6m3mol−1), and tert (6.28 × 10−6m3mol−1) in the α-cyclodextrin system. The aim of this work was to reveal the effect of the hydrophilic part of a guest molecule on the kinetic parameters in an inclusion reaction with α-cyclodextrin. Ultrasonic absorption measurements in the frequency range from 0.2 to 8 MHz were carried out for α-cyclodextrin solutions with pentanol isomers at 25°C by using resonator methods. The rate and the equilibrium constants were obtained from the concentration dependence of the relaxation frequency, and the standard volume changes of the complexation reaction were obtained from the maximum absorption per wavelength. A single relaxational absorption was observed, and the cause of the relaxation was attributed to a perturbation of the chemical equilibrium associated with a complexation reaction between α- cyclodextrin and pentanol isomers. The backward rate constant, kb, depended on the structure of the guest molecules. The value of kb was affected by the stability of host-guest complex, which depended on the position of the hydroxy group. In complex formation between α-cyclodextrin and pentanol isomers, the values of kb increased in the order of nor (kb = 2.23 × 106s−1), sec (kb = 3.46 × 106s−1), and tert (kb = 8.77 × 106s−1). In addition, standard volume changes, V , increased in the order of nor (4.12 × 10−6m3mol−1), sec (4.67 × 10−6m3mol−1), and tert (6.28 × 10−6m3mol−1) in the α-cyclodextrin system.

Ultrasonic Absorption Measurements of Bovine Serum Albumin Solutions in the Frequency Range 200 kHz to 3 MHz

배종림,Bae, Jong-Rim The Acoustical Society of Korea 2006 韓國音響學會誌 Vol.25 No.e1

Ultrasonic absorption and velocity spectra in bovine serum albumin (BSA) aqueous solutions have been measured at $20^{\circ}C$ over the frequency range 0.2-3 MHz in the pH range 1.5-13.2. The high-Q ultrasonic resonator and pulse-echo overlap methods were used. At acid pH's, excess absorption over that of pH 7 was explained by double relaxation. The pH dependences of the relaxation frequency and maximum absorption per wavelength, showed that the relaxation at about 200 kHz was related to the expansion of molecules and that about 3 MHz resulted from the proton transfer reaction of carboxyl group. At alkaline pH's, the excess absorption was explained by double relaxation. The relaxation at about 300 kHz was associated with a helix-coil transition, and that about 3 MHz was attributed to the proton transfer reaction of phenolic group. The rate constants and volume changes associated with these processes were estimated.

사이크로덱스트린과 나프로젠의 복합체 형성과 붕괴반응에 의한 초음파 완화

배종림 한국물리학회 2014 새물리 Vol.64 No.1

나프로젠 (pH ~6.0)만의 수용액과 나프로젠 (guest)과 β-사이크로덱스트린 (β-CD, host)이 함께 공존하는 수용액에 대하여 각각 0.2 - 8.1 MHz의 주파수 범위에서 초음파 흡수측정을 행하였다. β-CD와 나프로젠이 함께 존재할 때만 초음파 단일 완화현상이 관측되었고, 그 완화주파수는 1 MHz이하의 저주파수 영역에 존재하였다. 단일 완화현상의 원인은 β-CD 와 나프로젠과의 복합체 형성과 붕괴반응에 의한 화학평행의 혼란상태에 의한 것으로 해석하였다. 복합체 형성 (kf = 1.3 × 10^8 M^−1s^−1)과 붕괴속도상수 (kb = 2.5 × 10^6 s−1) 그리고 반응에 의한 표준체적변화 (△V = 13 × 10^−6 m^3mol^−1) 는 guest농도에 따른 완화주파수의 의존성과 파장당 최대흡수치의 의존성으로부터 각각 구했다. 속도상수들은 아스피린과 비교하였다. Ultrasonic absorption coefficients were measured in aqueous solutions of naproxen (pH ~6.0, guest) in the presence and the absence of β-cyclodextrin (β-CD, host) in the frequency range of 0.2 - 8.1 MHz with emphasis on the low-frequency range below 1 MHz. A single relaxational absorption was observed only in the solutions containing the guest and the host. From the concentration dependences of naproxen on the relaxation time and on the maximum absorption per wavelength, the cause of the relaxation was attributed to a perturbation of the chemical equilibrium associated with the formation of a complex between β-CD and naproxen. We determined reliable rate constants for the formation (kf = 1.3 × 10^8 M^−1s^−1) and the breakup (kb = 2.5 × 10^6 s−1) of the complex. We also obtained the equilibrium constant (K = 51.6 M^−1) and the standard volume change (△V = 13 × 10^−6 m^3mol^−1) of the reaction. We then compared the obtained rate constants and thermodynamic parameters with those of aspirin.

초음파완화법에 의한 카르복실산과 사이크로덱스트린의 복합체 형성반응의 속도론

배종림 한국물리학회 2012 새물리 Vol.62 No.2

Ultrasonic absorption coefficients in an aqueous solution of butanoic and pentanoic acid (pH= 6.0)(guest) were measured in the presence and the absence of β-cyclodextrin (β-CD)(host) at 25 ℃ in the frequency range 0.2-45MHz. A single relaxational phenomenon was observed only when the solutes were coexisting, but no relaxation was found in the β-CD solution or in the acid solutions. The ultrasonic relaxation observed in these solutions was due to a perturbation of the chemical equilibrium related to a reaction of an inclusion complex formed by the host and guest. The equilibrium constant was obtained from the dependence of the maximum absorption per wavelength on the guest concentration. The rate constant for the inclusion process of the guest into a cavity of β-CD and that for the leaving process from the cavity were determined from the obtained relaxation frequency and the equilibrium constant. The standard volume change of the reaction was also computed from the maximum absorption per wavelength. The hydrophobicity of guest molecules sas found to play an important role in the formation of the inclusion complex. β-사이크로덱스트린(β-CD)(host)와 카르복실산(guest)이공존하는 수용액에 대하여 초음파흡수측정을 0.2-45 MHz의주파수영역에서 행하여 host와 guest의 복합체 형성반응의 속도론적연구를 행하였다. 초음파 단일완화현상이 β-CD와 부탄산(pH = 6.0),β-CD와 펜탄산(pH = 6.0)의 수용액에서는각각 관측되었지만, 부탄산, 펜탄산, 그리고 β-CD만의수용액에서는 완화현상이 관측되지 않았다. 이 단일완화현상의 원인은복합체 형성반응에 의한 화학평행의 혼란상태에 의한 것으로 해석하였다. 평행상수는 guest농도에 따른 파장당 최대흡수치의 의존성으로부터구했다. 복합체 형성과 붕괴속도상수는 평행상수와 완화주파수로부터결정하였다. 또한 반응에 의한 표준체적변화도 파장당 최대흡수치로 부터계산하였다. Guest분자의 소수성그룹이 복합체의 안정성에 중요한 역할을하는 것을 알았다.

Study of the Dynamic Complex Formation of Pentanoic Acid with β-cyclodextrin by Using an Ultrasonic Relaxation Method

배종림 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.2

This study examined the effects of pentanoic acid as a guest molecule on the inclusion complex formation with β-cyclodextrin (β-CD). Ultrasonic absorption measurements were carried out for β-CD solutions with pentanoic acid over the frequency range from 0.2 to 45 MHz. A single relaxational absorption resulting from the perturbation of chemical equilibrium was observed for the inclusion of pentanoic acid into the β-CD cavity. The undissociated form of pentanoic acid produced a more stable complex with β-CD than its dissociated form. An ultrasonic relaxation associated with a protontransfer reaction was also observed when no additive was present in the solution.

Methylcyclohexane과 Methyl Acetate의 초음파 흡수측정

배종림,김상한 대구대학교 (한사대학) 산업기술연구소 1992 産業技術硏究 Vol.11 No.-

Methylcyclohexane의 축-적도형 이성체간 및 methyl acetate의 cis-trans형 이성체간의 신뢰성 높은 활성화에너지(△H^(*))와 에너지차(△H)를 구하기 위해 초음파흡수측정을 주파수 0.1-10MHz, 온도 5-60℃에 걸쳐 행하였다. 측정법으로는 0.1-10MHz의 범위에서 정확도 좋게 초음파흡수측정이 가능한 plano-concave공명법을 사용하였다. 그 측정결과 methylcyclohexane과 methyl acetate이성체간 활성화에너지를 각각 △H^(*)=10.0kcal/mol, 6.6kcal/mol으로, 이성체간의 에너지차를 각각 △H=1.8kcal/mol, 3.4kcal/mol으로 구하였다.

Measurements of the Ultrasonic Absorption in κ-Carrageenan Sols and Gels

배종림 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.6

Ultrasonic absorption has been measured in Κ-carrageenan sols and gels in the frequency range of 0.2 − 40 MHz. Two techniques, the high-Q ultrasonic resonator method and the optical beam deflection method by ultrasonic waves, have been used to cover the wide range of frequency. The absorption spectra observed both in the sols and gels could well be analyzed with a relaxation equation involving a distribution of relaxation times. A change in the relaxation parameters upon gelation of Κ-carrageenan has been observed: the relaxation frequency decreased, the relaxation strength increased, and the distribution of relaxation times became wider. The results show that the strong relaxations observed in the gel state are due to a change of state of hydration during the conformational random-coil-to-helix transition of the polymer chains. Therefore, the relaxation mechanism is discussed in the light of the hydration equilibrium of Κ-carrageenan polymers. The ultrasonic technique is demonstrated to be useful for monitoring the gelation process. Ultrasonic absorption has been measured in Κ-carrageenan sols and gels in the frequency range of 0.2 − 40 MHz. Two techniques, the high-Q ultrasonic resonator method and the optical beam deflection method by ultrasonic waves, have been used to cover the wide range of frequency. The absorption spectra observed both in the sols and gels could well be analyzed with a relaxation equation involving a distribution of relaxation times. A change in the relaxation parameters upon gelation of Κ-carrageenan has been observed: the relaxation frequency decreased, the relaxation strength increased, and the distribution of relaxation times became wider. The results show that the strong relaxations observed in the gel state are due to a change of state of hydration during the conformational random-coil-to-helix transition of the polymer chains. Therefore, the relaxation mechanism is discussed in the light of the hydration equilibrium of Κ-carrageenan polymers. The ultrasonic technique is demonstrated to be useful for monitoring the gelation process.

Polyacrylamide/ 물 이성분용액의 초음파 음속 및 흡수측정

배종림 한국물리학회 2003 새물리 Vol.47 No.4

The ultrasonic velocity at 3 MHz, using the pulse-echo-overlap method over the temperature range of 10 - 90 $^\circ$C, and absorption coefficient, using the high-Q ultrasonic resonator method at 30 $^\circ$C over the frequency range of 0.2 - 2.2 MHz were measured in an aqueous solution of polyacrylamide over the concentration range of 0.5 to 2.5 wt\%. The velocity exhibited a maximum value at approximately 70, 71, 72, 73 and 74$^\circ$C in the 2.5, 2.0, 1.5, 1.0, and 0.5 wt\% solutions, respectively. The velocity increased with concentration at a given temperature. The ultrasonic absorption $\alpha$/f$^2$ at a given temperature increased linearly with concentration below 1.5 wt\%, but increased suddenly above 1.5 wt\%. $\alpha$/f$^2$ for freqency above over 1 MHz was entirely due to the classical Stoke's viscous effect. The ultrasonic relaxation was observed in polyacrylamide aqueous solutions and may be the result of structural fluctuations of polymer molecules such as the segmental motion of polymer chains. At 2.5 wt\%, $\alpha$/f$^2$ suddenly increased with decreasing frequency. The shear viscosity decreased with temperature and increased with concentration.\end{abstract} Polyacrylamide 수용액에 대한 3 MHz의 초음파 음속측정과 0.2 $\sim$ 2.2 MHz의 범위에 대한 흡수계수 측정을 하였다. 음속은 펄스법을 사용하여 농도 0.5$\sim$2.5 wt\%, 온도 10 $\sim$ 90 $^\circ$C에 대하여 측정한 결과, 음속은 순수한 물에 대한 음속의 온도 의존성을 반영하고, 농도가 증가할수록 음속의 최대치는 낮은 온도 쪽으로 이동함을 알 수 있었다. 흡수계수측정은 광 회절 초음파 공명법을 사용하여 농도 0.5 $\sim$ 2.5 wt\%, 30 $^\circ$C에서 행하였다. 그 결과, polyacrylamide 수용액의 초음파 완화 메카니즘은 고분자 chain의 부분운동에 의한 것임을 처음으로 관측하였고, 주어진 온도에서 $\alpha$/$f^2$는 농도 1.5 wt\% 이하에서는 농도와 함께 선형적으로 증가하였다. 그러나 1.5 wt\% 이상의 농도에서는 급격히 증가하였다. 그리고 주파수 1 MHz 이상에서의 $\alpha$/$f^2$는 Stoke 점성에 의한 것임을 알았다.

Ultrasonic Measurement in Bovine Serum Albumin Solution

배종림,장승현,Jong-Rim Bae,Seung Hyun Chang Korean Chemical Society 1992 대한화학회지 Vol.36 No.2

단백질 수용액 중의 초음파흡수 mechanism을 규명하기 위하여 pH 7의 소혈청 albumin(BSA)수용액의 초음파흡수 측정을 주파수 100 kHz에서 1600 MHz에 걸쳐 행하였다. 측정방법은 plano-concave 공명법(0.1${\sim}$10 MHz)과 고분해능 Bragg 반사법(120${\sim}$1600 MHz)을 사용하였다. pH7에서의 초음파흡수스펙트럼은 Davidson-Cole 분포식의 거울상인 분포함수를 사용한 완화곡선과 일치하였다. 이 완화현상을 BSA 분자의 수화평행에 의한 것으로 해석하였다. Ultrasonic absorption was measured in bovine serum albumin (BSA) aqueous solution (50 g/l) in the frequency range from 100 kHz to 1600 MHz at neutral pH. Three experimental techniques were used to cover the wide frequency range : plano-concave resonator, conventional Bragg reflection, and high-resolution Bragg reflection methods. The absorption spectrum at neutral pH fitted the relaxation curve well using the distribution function of a mirror image of Davidson-Cole function. The relaxaition behavior was interpreted in terms of various degree of hydration of BSA molecules.

젤라틴의 겔-졸전이에 의한 초음파 음속 및 흡수변화

배종림 한국물리학회 2005 새물리 Vol.51 No.3

The Ultrasonic velocity and the absorption coecient over the frequency range of 0.2 2 MHz were measured for gelation in gelatin by using the high-Q ultrasonic resonator method at 15 40 C.The gelation process induced by heat showed a marked increase in absorption and a slight decrease in velocity. The absorption spectrum showed broad distributions of relaxation times, which broadened with the gelation process. The decrease in velocity with a gelation process was associated with a decrease in the amount of hydrated water in random-coil equilibrium. The increase in absorption was interpreted in terms of various degrees of hydration that result when molecules exchange their positions among dierent layers and between the outer layer and the bulk water. 젤라틴의 졸, 겔 상태의 초음파 음속.흡수측정을 온도15 ~ 40,$, 0.2 ~ 2 MHz의 주파수영역에 걸쳐 광 회절 초음파공명법을 이용하여 행하였다. 온도 의존성의 결과, 겔화에 의해 음속은 약간 감소하고 흡수는 크게 증가하는 것을 알았다. 흡수스펙트럼의 측정결과는 졸, 겔 상태 모두에서 다중 완화현상이 존재함을 보였고 겔화하면 완화시간의 분포가 넓어졌다. 겔화에 의한 음속의 감소는 고분자의 random coil-helix전이로 젤라틴분자에 속박된 물분자수의 감소로 인한 것임을 알았다. 또 흡수증가는 고분자에 속박된 물분자와속박되지 않은 물분자 사이의 교환반응으로 완화시간이 길어지는 것으로생각된다.