蛋氨酸在KCl溶液中的解离常数与活度系数

doi:10.11949/0438-1157.20210291

摘要/Abstract

摘要：

采用改变pH法在25、30和35℃下测定了质量浓度为0.25~4.0 mol/kg的KCl水溶液中蛋氨酸的解离常数，计算得到了蛋氨酸的质子化焓；采用电动势法在25℃测量了0.025~0.200 mol/kg蛋氨酸溶液中浓度为0.1~1 mol/kg的KCl的活度系数，计算得到了KCl溶液中蛋氨酸的活度系数。结果表明，蛋氨酸在KCl水溶液中的解离常数随温度上升而减小、随KCl浓度增加而增大；25℃下，蛋氨酸在KCl水溶液中的活度系数随蛋氨酸浓度增大先减小后增大。运用德拜-休克尔模型和Pitzer模型对解离常数和活度系数的实验数据进行拟合，得到了相关参数，结果表明Pitzer模型的可靠性较好。

关键词: 解离常数, 活度系数, DL-蛋氨酸, 氯化钾, 平衡, 焓

Abstract:

The dissociation constants of methionine in KCl aqueous solutions with the molality of 0.25—4.0 mol/kg at 25℃, 30℃ and 35℃ were determined by changing the pH value, and the protonation enthalpies of methionine species were calculated. Methionine activity coefficients of 0.1—1 mol/kg KCl in 0.025—0.200 mol/kg DL-methionine solution were measured by electromotive force method at 25℃, and the activity coefficients of methionine in KCl aqueous solutions were calculated. The results showed that the dissociation constants of methionine in KCl aqueous solution decreased with the increase of temperature and increased with the increase of KCl concentration. The activity coefficients of methionine in KCl aqueous solutions at 25°C decreased first and then increased with the increase of methionine concentration. Debye-Huckel model and Pitzer model were used to fit the experimental datas of dissociation constants and activity coefficients, and the relevant parameters were obtained. The results show that the reliability of the Pitzer model is better.

Key words: dissociation constant, activity coefficient, DL-methionine, KCl, equilibrium, enthalpy

中图分类号:

TQ 021.8

陈志荣, 童云, 袁慎峰, 尹红. 蛋氨酸在KCl溶液中的解离常数与活度系数[J]. 化工学报, 2021, 72(9): 4469-4478.

Zhirong CHEN, Yun TONG, Shenfeng YUAN, Hong YIN. Dissociation constants and activity coefficients of methionine in KCl aqueous solutions[J]. CIESC Journal, 2021, 72(9): 4469-4478.

图/表 14

图1 活度系数测量装置

Fig.1 Activity coefficient measuring system

表1 蛋氨酸在KCl水溶液中的解离常数

Table 1 pKi*（±S.D.） for methionine in KCl solutions at different temperatures

T/℃	m_KCl/(mol/kg)	pK₁^*	pK₂^*	c_KCl/(mol/L)	pK₁^*	pK₂^*
25	0.25	2.163±0.004	9.098±0.003	0.25	2.167	9.102
	0.5	2.186±0.006	9.108±0.006	0.49	2.193	9.115
	1.0	2.240±0.003	9.138±0.004	0.97	2.254	9.152
	1.5	2.299±0.007	9.225±0.001	1.43	2.319	9.244
	2.0	2.361±0.009	9.300±0.006	1.89	2.387	9.326
	3.0	2.485±0.009	9.463±0.007	2.75	2.523	9.501
	4.0	2.616±0.010	9.640±0.007	3.55	2.667	9.691
30	0.25	2.158±0.002	8.969±0.001	0.25	2.162	8.973
	0.5	2.181±0.004	8.979±0.003	0.49	2.188	8.986
	1.0	2.230±0.002	9.028±0.004	0.97	2.243	9.041
	1.5	2.288±0.006	9.093±0.004	1.43	2.307	9.112
	2.0	2.344±0.005	9.167±0.008	1.89	2.370	9.193
	3.0	2.456±0.010	9.328±0.009	2.75	2.494	9.366
	4.0	2.587±0.011	9.500±0.012	3.55	2.640	9.551
35	0.25	2.155±0.003	8.846±0.004	0.25	2.159	8.850
	0.5	2.174±0.005	8.855±0.006	0.49	2.181	8.862
	1.0	2.223±0.002	8.903±0.005	0.97	2.236	8.916
	1.5	2.276±0.004	8.967±0.006	1.43	2.295	8.986
	2.0	2.330±0.006	9.038±0.005	1.89	2.356	9.064
	3.0	2.445±0.008	9.199±0.008	2.75	2.483	9.237
	4.0	2.564±0.010	9.369±0.011	3.55	2.615	9.420

图2 KCl溶液中蛋氨酸解离常数与离子强度的关系

Fig.2 pKi*(molar scale) for methionine in KCl solutions as a function of ionic strength

表2 蛋氨酸在不同离子强度下的质子化焓

Table 2 Enthalpy of dissolution at different ionic strength

I/(mol/kg)	-ΔH₁^*/(kJ/mol)	-ΔH₂^*/(kJ/mol)
0.25	1.4	44.3
0.5	2.1	44.5
1.0	3.1	45.0
1.5	4.1	45.4
2.0	5.4	46.1
3.0	7.0	46.4
4.0	9.1	47.7

图3 蛋氨酸在25℃下的KCl、NaCl和KNO3水溶液中解离常数的对比

Fig.3 Comparison of pKi* (molar scale) for methionine in KCl, NaCl and KNO3 solutions(T=25℃)

表3 电池（1）的电势值

Table 3 Values of electrochemical cell（1）

m_KCl/(mol/kg)	E₊/mV	E_-/mV	ΔE⁽¹⁾/mV	$γ ± (1)$	ln(m_s $γ ± (1)$ )
0.1	151.3	48.2	103.1	0.76777	-2.5669
0.3	175.5	21.0	154.5	0.68627	-1.5805
0.5	187.3	8.6	178.7	0.64902	-1.1254
0.7	195.4	0.6	194.8	0.62599	-0.8251
1.0	203.6	-8.2	211.8	0.60389	-0.5044

表3 电池（1）的电势值

Table 3 Values of electrochemical cell（1）

m_KCl/(mol/kg)	E₊/mV	E_-/mV	ΔE⁽¹⁾/mV	$γ ± (1)$	ln(m_s $γ ± (1)$ )
0.1	151.3	48.2	103.1	0.76777	-2.5669
0.3	175.5	21.0	154.5	0.68627	-1.5805
0.5	187.3	8.6	178.7	0.64902	-1.1254
0.7	195.4	0.6	194.8	0.62599	-0.8251
1.0	203.6	-8.2	211.8	0.60389	-0.5044

表4 KCl在KCl-蛋氨酸水溶液和KCl溶液中的平均活度系数γ±(2)与γ±(1)的比值

Table 4 Ratio of mean ionic activity coefficient of KCl in methionine aqueous solution to that in water at different molalities of KCl and methionine

m_A/(mol/kg)	m_KCl/(mol/kg)
m_A/(mol/kg)	0.1	0.3	0.5	0.7	1.0
0.025	1.0018	1.0022	1.0025	1.0029	1.0035
0.050	1.0026	1.0035	1.0041	1.005	1.0062
0.100	1.0026	1.0042	1.0058	1.0074	1.0099
0.150	1.0018	1.0045	1.0067	1.0093	1.0129
0.200	1.0019	1.0051	1.0082	1.0117	1.0165

表5 式（29）参数值

Table 5 Coefficients of Eq.（29）

参数	参数值
a₁	1.5854×10^-1
a₂	1.5835×10^-1
a₃	-1.6440
a₄	6.6315×10^-4
a₅	4.3176
a₆	1.3558×10^-2

表6 蛋氨酸在KCl-蛋氨酸水溶液与蛋氨酸水溶液中活度系数γA(2)和γA(1)的比值

Table 6 Ratio of mean ionic activity coefficients of methionine in the presence of KCl aqueous solution to that in water at different molalities of KCl and methionine

m_A/(mol/kg)	m_KCl/(mol/kg)
m_A/(mol/kg)	0.1	0.3	0.5	0.7	1.0
0.025	1.0093	1.0330	1.0641	1.1031	1.1784
0.050	1.0035	1.0153	1.0338	1.0595	1.1125
0.100	0.9967	0.9950	0.9998	1.0111	1.0408
0.150	0.9965	0.9944	0.9987	1.0097	1.0389
0.200	1.0027	1.0132	1.0305	1.0550	1.1064

图4 蛋氨酸浓度对γA(2)/γA(1)的影响

Fig.4 Effect of methionine molality on γA(2)/γA(1)

图5 KCl浓度对γA(2)/γA(1)的影响

Fig.5 Effect of KCl molality on γA(2)/γA(1)

表7 DH模型参数

Table 7 Parameters of DH model

i	A_i	$- l g K i 0$	S.E.
1	0.2095	2.437	0.019
2	0.2380	9.339	0.0074

表7 DH模型参数

Table 7 Parameters of DH model

i	A_i	$- l g K i 0$	S.E.
1	0.2095	2.437	0.019
2	0.2380	9.339	0.0074

表8 不同温度下KCl水溶液中蛋氨酸各形式的Pitzer模型参数

Table 8 Pitzer coefficients for methionine species in KCl media at different temperatures

T/K	Species	$l n K i$	$β i 0$	$β i 1$	$C i$	S.E.
298.15	H₂B⁺	-4.939	0.1009	9.316	0.03460	0.0019
303.15	H₂B⁺	-4.912	0.1340	9.199	0.03002	0.0077
308.15	H₂B⁺	-4.931	0.1040	9.348	0.0348	0.00169
298.15	B^-	-22.10	0.1530	-5.810	0.05501	0.0110
303.15	B^-	-21.82	0.1594	-5.807	0.05449	0.0125
308.15	B^-	-21.55	0.1593	-5.771	0.05533	0.0128

表8 不同温度下KCl水溶液中蛋氨酸各形式的Pitzer模型参数

Table 8 Pitzer coefficients for methionine species in KCl media at different temperatures

T/K	Species	$l n K i$	$β i 0$	$β i 1$	$C i$	S.E.
298.15	H₂B⁺	-4.939	0.1009	9.316	0.03460	0.0019
303.15	H₂B⁺	-4.912	0.1340	9.199	0.03002	0.0077
308.15	H₂B⁺	-4.931	0.1040	9.348	0.0348	0.00169
298.15	B^-	-22.10	0.1530	-5.810	0.05501	0.0110
303.15	B^-	-21.82	0.1594	-5.807	0.05449	0.0125
308.15	B^-	-21.55	0.1593	-5.771	0.05533	0.0128

图6 pKi*实验值与计算值之差

Fig.6 Deviations between the measured and calculated pKi*

参考文献 37

1	Finkelstein J D. Methionine metabolism in liver diseases[J]. The American Journal of Clinical Nutrition, 2003, 77(5): 1094-1095.
2	Willke T. Methionine production: a critical review[J]. Applied Microbiology and Biotechnology, 2014, 98(24): 9893-9914.
3	Antony R, Li Y F. BDNF secretion from C₂C₁₂ cells is enhanced by methionine restriction[J]. Biochemical and Biophysical Research Communications, 2020, 533(4): 1347-1351.
4	Yesmin S, Uddin M E, Chacrabati R, et al. Effect of methionine supplementation on the growth performance of rabbit[J]. Bangladesh Journal of Animal Science, 2013, 42(1): 40-43.
5	Wang J, Cui K, Ma T, et al. Effects of dietary methionine deficiency followed by replenishment on the growth performance and carcass characteristics of lambs[J]. Animal Production Science, 2019, 59(2): 243.
6	Sanderson S M, Gao X, Dai Z, et al. Methionine metabolism in health and cancer: a nexus of diet and precision medicine[J]. Nature Reviews. Cancer, 2019, 19(11): 625-637.
7	Lees E K, Król E, Grant L, et al. Methionine restriction restores a younger metabolic phenotype in adult mice with alterations in fibroblast growth factor 21[J]. Aging Cell, 2014, 13(5): 817-827.
8	Oguzie E E, Li Y, Wang F H. Corrosion inhibition and adsorption behavior of methionine on mild steel in sulfuric acid and synergistic effect of iodide ion[J]. Journal of Colloid and Interface Science, 2007, 310(1): 90-98.
9	Lussling T, Muller K P, Schreyer G, et al. Process for the recovery of methionine and potassium bicarbonate: US4303621[P]. 1981-12-01.
10	Consortium Fuer Elektrochemische Industrie Gmbh. Method for fermentative production of L-methionine: CA20042456483[P]. 2004-08-05.
11	Sanders J P M, Sheldon R A. Comparison of the sustainability metrics of the petrochemical and biomass-based routes to methionine[J]. Catalysis Today, 2015, 239: 44-49.
12	韩振亚, 苏焕斌, 张燕, 等. 蛋氨酸生产现状分析[J]. 广东化工, 2015, 42(19): 101-102.
	Han Z Y, Su H B, Zhang Y, et al. The production situation of D, L-methionine analysis[J]. Guangdong Chemical Industry, 2015, 42(19): 101-102.
13	Niu Q, Zhou C R, Zhan Z L. Investigation on standard molar enthalpy of combustion, specific heat capacity and thermal behavior of methionine[J]. Journal of Thermal Analysis and Calorimetry, 2018, 132(3): 1805-1811.
14	Sharma V K, Zinger A, Millero F J, et al. Dissociation constants of protonated methionine species in NaCl media[J]. Biophysical Chemistry, 2003, 105(1): 79-87.
15	Lytkin A I, Chernikov V V, Krutova O N, et al. Thermodynamics of the dissolution of crystalline L-methionine in water[J]. Russian Journal of Physical Chemistry A, 2016, 90(5): 969-972.
16	Soto-Campos A M, Mohammad K K, Juan H V. Activity coefficients of the electrolyte and the amino acid in water + NaNO₃+ glycine and water + NaCl + DL-methionine systems at 298.15 K[J]. Biophysical Chemistry, 1997, 67(1/2/3):97-105.
17	Pathare B, Tambe V, Patil V. A review of analytical techniques for determination of dissociation constant[J]. International Journal of Pharmacy and Pharmaceutical Sciences, 2014, 6(8): 2747-2757.
18	Lebrón-Paler A, Pemberton J E, Becker B A, et al. Determination of the acid dissociation constant of the biosurfactant monorhamnolipid in aqueous solution by potentiometric and spectroscopic methods[J]. Analytical Chemistry, 2006, 78(22): 7649-7658.
19	Ray P C, Munichandraiah N, Das P K. Dissociation constants of some substituted cinnamic acids in protic solvents: measurements by hyper-Rayleigh scattering and potentiometric techniques[J]. Chemical Physics, 1996, 211(1/2/3): 499-505.
20	Jano I, Hardcastle J E, Zhao K, et al. General equation for calculating the dissociation constants of polyprotic acids and bases from measured retention factors in high-performance liquid chromatography[J]. Journal of Chromatography A, 1997, 762(1/2): 63-72.
21	Hardcastle J E, Vermillion-Salsbury R, Zhao K, et al. Use of secondary equilibria in reversed-phase high-performance liquid chromatography for the determination of dissociation constants of polyprotic leukotrienes[J]. Journal of Chromatography A, 1997, 763(1/2): 199-203.
22	王水. 7-氨基头孢烷酸反应结晶过程研究[D]. 天津:天津大学, 2005.
	Wang S. Reaction crystallization process of 7-aminocephalosporic acid [D]. Tianjin: Tianjin University, 2005.
23	王琴萍, 邢长宇, 陈洪涛, 等. HCl-NaCl-C₂H₆O₂-H₂O体系中HCl热力学[J]. 化工学报, 2004, 55(9): 1406-1411.
	Wang Q P, Xing C Y, Chen H T, et al. Thermodynamics of HCl in system of HCl-NaCl-C₂H₆O₂-H₂O[J]. Journal of Chemical Industry and Engineering (China), 2004, 55(9): 1406-1411.
24	Zemaitis J F, Clark D M, Rafal M, et al. Handbook of Aqueous Electrolyte Thermodynamics[M]. Hoboken, NJ, USA: John Wiley & Sons, Inc., 1986.
25	The National Institute of Standards and Technology. Solubility [DS/OL]. [2021-01-01]. .
26	Nightingale E R. Phenomenological theory of ion solvation. effective radii of hydrated ions[J]. The Journal of Physical Chemistry, 1959, 63(9): 1381-1387.
27	Pinho S P, Silva C M, Macedo E A. Solubility of amino acids: a group-contribution model involving phase and chemical equilibria[J]. Industrial & Engineering Chemistry Research, 1994, 33(5): 1341-1347.
28	Khoshkbarchi M K, Vera J H. A simplified perturbed hard-sphere model for the activity coefficients of amino acids and peptides in aqueous solutions[J]. Industrial & Engineering Chemistry Research, 1996, 35(11): 4319-4327.
29	Mohammad K K, Juan H V. Measurement of activity coefficients of amino acids in aqueous electrolyte solutions: experimental data for the systems H₂O + NaCl + glycine and H₂O + NaCl + DL-alanine at 25℃[J]. Industrial & Engineering Chemistry Research, 1996, 35 (8): 2735-2742.
30	Khoshkbarchi M K, Vera J H. Effect of NaCl and KCl on the solubility of amino acids in aqueous solutions at 298.2 K: measurements and modeling[J]. Industrial & Engineering Chemistry Research, 1997, 36(6): 2445-2451.
31	Pitzer K S. Thermodynamics of electrolytes (I): Theoretical basis and general equations[J]. The Journal of Physical Chemistry, 1973, 77(2): 268-277.
32	Bretti C, Giuffrè O, Lando G, et al. Solubility, protonation and activity coefficients of some aminobenzoic acids in NaCl_aq and (CH₃)₄NCl_aq, at different salt concentrations, at T = 298.15 K[J]. Journal of Molecular Liquids, 2015, 212: 825-832.
33	William M H. CRC Handbook of Chemistry and Physics[M]. 96th ed. Boca Raton: CRC Press, 2014: 1077.
34	Anderko A, Wang P M, Rafal M. Electrolyte solutions: from thermodynamic and transport property models to the simulation of industrial processes[J]. Fluid Phase Equilibria, 2002, 194/195/196/197: 123-142.
35	Millero F J, Pierrot D. A chemical equilibrium model for natural waters[J]. Aquatic Geochemistry, 1998, 4(1): 153-199.
36	Møller N. The prediction of mineral solubilities in natural waters: a chemical equilibrium model for the Na-Ca-Cl-SO₄-H₂O system, to high temperature and concentration[J]. Geochimica et Cosmochimica Acta, 1988, 52(4): 821-837.
37	Pitzer K S. Activity Coefficients in Electrolyte Solutions[M]. 2nd ed. Boca Raton: CRC Press, 2018: 76-143.

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