Kinetic and Thermodynamic Aspects of Phosphate Diester Hydrolysis in Alkaline Solutions: The Role of Non-Leaving Groups
- سال انتشار: 1403
- محل انتشار: فصلنامه شیمی آلی-فلزی کاربردی، دوره: 4، شماره: 1
- کد COI اختصاصی: JR_JAOC-4-1_001
- زبان مقاله: انگلیسی
- تعداد مشاهده: 55
نویسندگان
Libyan Authority for Scientific Research, Tripoli, Libya
Misurata University, Faculty of Education, Chemistry Department, Misurata, Libya
Misurata University, Faculty of Science, Chemistry Department, Misurata, Libya
Misurata University, Faculty of Science, Chemistry Department, Misurata, Libya
چکیده
Alkaline hydrolysis of phosphate diester compounds with a common leaving group (LG) and varying non-leaving groups (NLG) was investigated. The nitrophenyl group was employed as a leaving group due to its favorable leaving group properties, significant absorbance for reaction monitoring, and selective cleavage of the phosphorus-oxygen bond, which is relevant for DNA and RNA degradation. Reactions were conducted under pseudo first-order conditions in NaOH solutions ۷۰ °C. In addition, the alkaline hydrolysis was studied using a ۱M NaOH solution at different temperatures (۵۰–۸۰ °C), pH (۱۲-۱۴) levels, and viscosities (with ۰% - ۴۰% glycerol). Reaction progress was continuously monitored by measuring the absorbance increase of the ۴-nitrophenolate ion at λ = ۴۰۰ nm. The rate constant (kobs) was determined by fitting the data to a first-order equation. The results demonstrate kobs increased with higher NaOH concentration, temperature, pH, and solution viscosity, except for NppNPP. Investigation of the effect of the non-leaving group's pKa revealed slight sensitivity of the hydrolysis reaction with βNLG = -۰.۱۲. Thermodynamic parameters were determined and the values were as follows: ∆H = ۴۸.۸ kJ.mol-۱, ∆S = -۱۷۱.۶ J.mol-۱.K-۱, ∆G = ۹۹.۹ kJ.mol-۱ for BpNPP; ∆H = ۶۴.۹ kJ.mol-۱, ∆S = -۱۲۷.۱ J.mol-۱.K-۱, ∆G = ۱۰۲.۸ kJ.mol-۱ for PypNPP; ∆H = ۸۶.۳ kJ.mol-۱, ∆S = -۷۶.۷ J.mol-۱.K-۱, ∆G = ۱۰۹.۲ kJ.mol-۱ for MpNPP, and ∆H = ۶۳.۷ kJ.mol-۱, ∆S = -۱۵۲ J.mol-۱.K-۱, and ∆G = ۱۰۹ k kJ.mol-۱ for NppNPP. All four hydrolysis processes have positive ∆G values, which means they are non-spontaneous and require external energy to proceed.کلیدواژه ها
Kinetic study, Thermodynamic study, Phosphate diesters, Alkaline hydrolysis, ۴-Nitrophosphate diestersاطلاعات بیشتر در مورد COI
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