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Journal articles on the topic 'Kinetics of the Base·Catalysed'

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Published: 5 June 2025

Last updated: 1 August 2025

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1

Crampton, Michael R., та Ian A. Robotham. "Kinetic studies of bold σ -adduct formation and nucleophilic substitution in the reactions of ethyl 2,4,6-trinitrophenyl ether, some phenyl 2,4,6-trinitrophenyl ethers, and phenyl 2,4-dinitronaphthyl ether with aniline in dimethyl sulfoxide". Canadian Journal of Chemistry 76, № 6 (1998): 627–34. http://dx.doi.org/10.1139/v97-225.

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The reaction of ethyl 2,4,6-trinitrophenyl ether with aniline in dimethyl sulfoxide containing Dabco occurs in two stages. The first gives 5, the σ -adduct intermediate on the substitution pathway, which has been identified spectroscopically. The second yields 2,4,6-trinitrodiphenylamine, the substitution product. Kinetic studies show that proton transfer is rate limiting both in the formation of the intermediate and in its subsequent acid-catalysed decomposition. Phenoxide is a considerably better leaving group than ethoxide and the substitution reactions of phenyl 2,4,6-trinitrophenyl ethers

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2

Zhang, Jin, Jia-qing Xie, Ying Tang, et al. "Hydrolysis of phosphate diester catalysed by transition metal complexes of a salicylaldimine Schiff base bearing dibenzo-18-crown-6." Journal of Chemical Research 2005, no. 2 (2005): 130–34. http://dx.doi.org/10.3184/0308234054497137.

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A new crowned Schiff base ligand and its cobalt(II) and manganese(III) complexes were synthesised and characterised. These complexes were used to catalyse the hydrolysis of bis(4-nitrophenyl) phosphate (BNPP) in order to mimic the action of hydrolytic metalloenzymes. The kinetics and the mechanism of the titled reactions were investigated. The change of the characteristic ultraviolet spectra of the reaction systems was also analysed. A kinetic mathematical model of BNPP cleavage catalysed by the complexes is proposed. The function of the crown ether ring and the effects of the reaction conditi

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3

Banerjee, Sudheer K., R. Shanker, and Om P. Sachdeva. "Kinetics of Pb(IV) Oxidation of Substituted Methyl Mandelates — A L.F. E. R. Study." Zeitschrift für Naturforschung B 41, no. 4 (1986): 467–72. http://dx.doi.org/10.1515/znb-1986-0411.

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Lead tetra acetate (Pb(IV) or LTA) oxidation of the esters X -C6H4-CH(OH)-COOCH3(X = H, m-NO2, p-NO2, m-Cl, p-Cl, p-Br. p-CH3 and p-C2H5) gives corresponding keto esters. The reaction is first order in [Pb(IV)] and second order in [Ester], and is catalysed by pyridine and 2,6-lutidine. The pyridine catalysed reaction is first order each in [Pb(IV)]. [Ester] and [Pyridine]. A kinetic isotope effect is observed in oxidation of methyl m andelate for both uncatalysed reaction (kH/kD = 4.2) and pyridine catalysed reaction (kH/kD = 1.8). Activation param eters for both uncatalysed and pyridine catal

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4

Monirul, Islam. "Kinetics and mechanism of hetero-aromatic N-base ligand 1,10-phenanthroline assisted chromic acid oxidation of DL-malic acid in aqueous micellar acid media." Journal of Indian Chemical Society Vol. 96, Oct 2019 (2019): 1333–42. https://doi.org/10.5281/zenodo.5642633.

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Department of Chemistry, Seth Anandram Jaipuria College, Kolkata-700 005, India <em>E-mail</em>: monirul_vu@yahoo.co.in, michem989@gmail.com <em>Manuscript received online 18 September 2019, accepted 24 September 2019</em> Hetero-aromatic N-base ligand like 1,10-phenanthroline (phen) assisted chromic acid oxidation of malic acid in aqueous sulfuric acid media have been studied under the experimental conditions, [malic acid]<sub>T</sub> >> [Cr(VI)<sub>T</sub> ] at different temperatures. Under the kinetic conditions, HCrO<sub>4</sub><sup>–</sup> has been found kinetically active in

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5

Engell, Karen M., Robert A. McClelland, and Poul E. Sørensen. "The decomposition of methyl hemiacetals of benzaldehyde in aqueous solution: a study of the effect of aromatic substitution." Canadian Journal of Chemistry 77, no. 5-6 (1999): 978–89. http://dx.doi.org/10.1139/v99-102.

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The acid-base catalysed decomposition of hydrates and hemiacetals of carbonyl compounds are classical examples of reactions where (slow) proton transfer is coupled with heavy atom reorganization, i.e., CO bond breaking and solvent reorganization. We have studied the influence of m- and p-substitution in the carbonyl electrophile on the kinetics of the acid and base catalysis of the decomposition of methyl hemiacetals of benzaldehyde. The experimental data are well described by three-dimensional More O'Ferrall - Jencks energy contour diagrams according to principles developed by Jencks (the BE

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6

Fedoroňko, Michal, Mária Petrušová, and Vladimír Kováčik. "Kinetics and mechanism of base-catalysed aldolization of 1,3-dimethoxy-2-propanone." Collection of Czechoslovak Chemical Communications 50, no. 10 (1985): 2252–59. http://dx.doi.org/10.1135/cccc19852252.

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1,3-Dimethoxy-2-propanone (HA) in an aqueous alkaline solution undergoes specifically base-catalysed aldolization with the formation of a dimer, 4-hydroxy-1,3,5-trimethoxy-4-methoxymethyl-2-pentanone (H2A2). The reaction is reversible and involves the formation or decomposition of an intermediate anion, HA2-, as the rate-determining step. The formation of a carbanion ion, A-, of the starting compound and of the HA2- anion are rapid, preceding, and generally base-catalysed reaction steps. The activation and thermodynamic parameters of the reversible reaction were determined from the dependences

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7

Jackson, WG, and RL Angel. "The SN1CB Mechanism in Non-Aqueous Solution." Australian Journal of Chemistry 41, no. 9 (1988): 1369. http://dx.doi.org/10.1071/ch9881369.

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The reaction between (NH3)5Co-NCMe3+ and dimethyl sulfoxide (Me2SO) to produce (NH3)5Co-OSMe23+ and MeCN in Me2SO solvent is general base-catalysed. The rates and rate laws have been determined for 10 substituted amines. First-order kinetics are observed, and the rates show a dependence which is less than first order on base (B) concentration. These facts are rationalized in terms of a common, reactive conjugate base (NH3)4(NH2)CoNCMe2+, the solvolysis of which occurs at a rate competitive with its rate of reprotonation by BH+. Alternative mechanisms are considered. The measured rates, which s

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8

Janík, Marek, Vojeslav Štěrba, Jiří Černý, Vladimír Macháček, and Petr Jansa. "Kinetics of base-catalysed ring closure of methyl 2,6-dinitrophenylsulfanylethanoate." Journal of Physical Organic Chemistry 18, no. 8 (2005): 844–49. http://dx.doi.org/10.1002/poc.949.

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9

P., A. Sarathi, A.Vijayakumar, Gnanasekaran C. та Shunmugasundaram A. "Base catalysed addition of thiophenol to β-nitrostyrene in aqueous acetonitrile - A kinetic study". Journal of Indian Chemical Society Vol. 81, Dec 2004 (2004): 1157–62. https://doi.org/10.5281/zenodo.5833645.

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Research Department of Chemistry, VHNSN College, Virudhunagar-626 001, India <em>E-mail</em> : shunmugee@hotmail.com <em>Manuscript received 11 October 2004</em> The kinetics of nucleophilic addition of thiophenol (PhSH) to β-nitrostyrene (βNS) has been investigated in 80% (v/v) acetonitrile-water at 25°C. The reaction follows second order, first order in each rcadant. The effect of solvent composition on the rate is significant that the decrease in polarity of the medium decreases the reaction rate. A mechanism involving the formation of zwitterionic addition complex in a fast e

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10

Rehman, Abdul, M. F. M. Gunam Resul, Valentine C. Eze, and Adam Harvey. "A kinetic study of Zn halide/TBAB-catalysed fixation of CO2 with styrene oxide in propylene carbonate." Green Processing and Synthesis 8, no. 1 (2019): 719–29. http://dx.doi.org/10.1515/gps-2019-0042.

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Abstract Synthesis of styrene carbonate (SC) via the fixation of CO2 with styrene oxide (SO) has been investigated using a combination of zinc bromide (ZnBr2) and tetrabutylammonium halides (TBAX) as acid-base binary homogeneous catalysts. The combination of ZnBr2 and TBAB had a synergistic effect, which led to about 6-fold enhancement in the rate of SC formation as compared to using TBAB alone as a catalyst. Propylene carbonate (PC) was chosen as a green solvent for a comprehensive study of reaction kinetics. The reaction followed a first-order kinetics with respect to SO, CO2, and TBAB, wher

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11

Frenna, Vincenzo, Gabriella Macaluso, Giovanni Consiglio, Susanna Guernelli, and Domenico Spinelli. "Kinetic Study of the Reactions of Some 5-Nitro-2-(4-nitrophenoxy)-3-X-thiophenes with Aniline and 4-Methoxyaniline in Methanol." Collection of Czechoslovak Chemical Communications 64, no. 11 (1999): 1877–92. http://dx.doi.org/10.1135/cccc19991877.

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The rate constants of the title reactions have been measured at various amine concentrations. The second-order kinetic constant for the amino substitution increases in a hyperbolic way as a function of the nucleophile concentration. The k3Am/k-1 ratio for each catalysed system is not a monotonic function of the X substituent. This result has been rationalized in the framework of the SB-GA (Specific Base-General Acid) mechanism of base catalysis.

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12

McClelland, Robert A., and Poule E. Sørensen. "Kinetics of the equilibration of 3-hydroxyphthalide and o-formylbenzoic acid. Hemiacetal breakdown with a carboxylic acid leaving group." Canadian Journal of Chemistry 64, no. 6 (1986): 1196–200. http://dx.doi.org/10.1139/v86-198.

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A temperature-jump relaxation study is reported for the equilibration: 3-hydroxyphthalide (SH) [Formula: see text]o-formylbenzoate (R−) [Formula: see text]o-formylbenzoic acid (RH). A kinetic analysis is carried out in which SH and R− interconvert with catalysis in the ring opening direction by water and by added general bases. Excellent Brønsted plots based upon a series of oxyacid buffer catalysts are obtained. These have slopes β for the base-catalyzed ring opening of 0.81 and α for the reverse acid-catalyzed ring closing of 0.19. A mechanism where S−, the conjugate base of SH, is a discret

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13

Encinar, José María, Juan Félix González, Gloria Martínez, and Sergio Nogales-Delgado. "Transesterification of Soybean Oil through Different Homogeneous Catalysts: Kinetic Study." Catalysts 12, no. 2 (2022): 146. http://dx.doi.org/10.3390/catal12020146.

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The search for alternatives to fossil fuels has been widely covered, especially in the past two decades. Thus, the role of biodiesel has been important, and its implementation in biorefineries seems feasible due to the sustainability of the process. This way, the knowledge of kinetics is vital to design industrial facilities and to compare the efficiency of catalysts (both typical and innovative ones) during transesterification or other similar processes taking place in a biorefinery, such as biolubricant production through transesterification with superior alcohols. In this work, a thorough k

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14

North, Michael, and Stephanie Urwin. "Kinetics and mechanism of base catalysed ethyl cyanoformate addition to aldehydes." Tetrahedron 70, no. 40 (2014): 7100–7105. http://dx.doi.org/10.1016/j.tet.2014.02.009.

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15

Al-Sakkari, E. G., S. T. El-Sheltawy, A. Soliman, and I. Ismail. "Transesterification of Low FFA Waste Vegetable Oil using Homogeneous Base Catalyst for Biodiesel Production: Optimization, Kinetics and Product Stability." Journal of Advanced Chemical Sciences 4, no. 3 (2018): 586–92. http://dx.doi.org/10.30799/jacs.195.18040305.

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The most common method of biodiesel production is base catalyzed transesterification where alkaline materials, such as potassium hydroxide, are used as a catalyst. This paper presents a study of factors affecting biodiesel production from low free fatty acids (FFA) content waste vegetable oil through base catalyzed transesterification as well as the optimum reaction conditions. The optimum conditions were found to be a time of 60 min, catalyst loading of 1% of oil mass, mixing speed of 400 rpm and temperature of 65 °C. It also introduces a kinetic study of this reaction to determine the best m

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16

Borzęcka, Nina Helena, Bartosz Nowak, Rafał Pakuła, Robert Przewodzki, and Jakub Maksymilian Gac. "Diffusion/Reaction Limited Aggregation Approach for Microstructure Evolution and Condensation Kinetics during Synthesis of Silica-Based Alcogels." International Journal of Molecular Sciences 24, no. 3 (2023): 1999. http://dx.doi.org/10.3390/ijms24031999.

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A base-catalysed methyltrimethoxysilane (MTMS) colloidal gel formation was implemented as a cellular automaton (CA) system, specifically diffusion and/or reaction-limited aggregation. The initial characteristic model parameters were determined based on experimental synthesis of MTMS-based, ambient-pressure-dried aerogels. The applicability of the numerical approach to the prediction of gels’ condensation kinetics and their structure was evaluated. The developed model reflects the kinetics properly within the investigated chemical composition range (in strongly reaction-limited aggregation cond

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17

North, Michael, and Marta Omedes-Pujol. "Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate." Beilstein Journal of Organic Chemistry 6 (November 3, 2010): 1043–55. http://dx.doi.org/10.3762/bjoc.6.119.

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Propylene carbonate can be used as a green solvent for the asymmetric synthesis of cyanohydrin trimethylsilyl ethers from aldehydes and trimethylsilyl cyanide catalysed by VO(salen)NCS, though reactions are slower in this solvent than the corresponding reactions carried out in dichloromethane. A mechanistic study has been undertaken, comparing the catalytic activity of VO(salen)NCS in propylene carbonate and dichloromethane. Reactions in both solvents obey overall second-order kinetics, the rate of reaction being dependent on the concentration of both the aldehyde and trimethylsilyl cyanide. T

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18

Xu, Mengxue, Hongpeng Zhang, Haiyan Zhu, Lianyuan Wang, and Chaohua Zhou. "Soman hydrolysis catalysed by hypochlorite ions." E3S Web of Conferences 267 (2021): 02043. http://dx.doi.org/10.1051/e3sconf/202126702043.

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Sarin (GB) and soman (GD) are severely toxic nerve agents that react slowly in water, resulting in long-term poisoning of the water and a serious threat to personnel. Some ions can catalyse GB and GD hydrolysis in water; the relevant research for GB is detailed, whereas that for GD is relatively less so. In this paper, GD hydrolysis catalysed by hypochlorite (ClO−) ions was studied via kinetic experiments. A fluorite-ion-specific electrode was used to monitor F− ions produced, allowing the rate constant and half-life of the GD hydrolysis to be calculated. The results showed that ClO− ions prom

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19

Bauerová, Ingrid, and Miroslav Ludwig. "Substituent Effects on the Base-Catalysed Hydrolysis of Phenyl Esters of para-Substituted Benzoic Acids." Collection of Czechoslovak Chemical Communications 65, no. 11 (2000): 1777–90. http://dx.doi.org/10.1135/cccc20001777.

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Seventeen model phenyl esters of 4-substituted benzoic acids were synthesised by the reaction of substituted benzoyl chlorides with phenol in aqueous alkaline solutions (Schotten-Baumann reaction), in pyridine (Einhorn reaction), or by the reaction of substituted benzoic acids with phosphorus oxychloride. Structures and purity of the model compounds were confirmed by 1H NMR and 13C NMR spectroscopy as well as by HPLC and elemental analysis. Phenyl 4-aminobenzoate was synthesised by reduction of phenyl 4-nitrobenzoate in methanol on palladium. Kinetics of base-catalysed hydrolysis of model phen

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20

Sevostyanova, N., and S. Batashev. "Cyclohexene hydrocarbomethoxylation catalysed by ruthenium compounds." Bulletin of Science and Practice 456, no. 11 (12) (2016): 99–105. https://doi.org/10.5281/zenodo.166790.

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This paper presents a catalytic activity of ruthenium (III) compounds in the model reaction of cyclohexene hydrocarbomethoxylation. The objective of the work was contained in the determination of the most active ruthenium catalyst of this reaction. The kinetic method was used as the main method of investigation. The gas–liquid chromatography method was used to analyze the reaction mass. Accordingly to approbation of ruthenium (III) acetylacetonate and chloride as catalysts of cyclohexene hydrocarbomethoxylation the higher catalytic activity of ruthenium chloride was determined. With using of r

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21

Nasreen, Sadia, Hui Liu, Ivana Lukic, Liaqat Qurashi, and Dejan Skala. "Heterogeneous kinetics of vegetable oil transesterification at high temperature." Chemical Industry and Chemical Engineering Quarterly 22, no. 4 (2016): 419–29. http://dx.doi.org/10.2298/ciceq160107011n.

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Currently, the catalytic efficiency and reusability of the solid base catalysts cannot meet the demand of industrial biodiesel production under low temperature. The purpose of this study is to define the kinetics of heterogeneous transesterification process which might be used for the prediction of the biodiesel synthesis at high temperature and pressure. The focus in this study was paid to recently reported data obtained with different catalysts used for biodiesel synthesis in a batch reactor at high temperatures. It was shown that three kinetic models that include: a) irreversible first orde

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22

Lamberti, Fabio M., Luis A. Román-Ramírez, Paul Mckeown, Matthew D. Jones, and Joseph Wood. "Kinetics of Alkyl Lactate Formation from the Alcoholysis of Poly(Lactic Acid)." Processes 8, no. 6 (2020): 738. http://dx.doi.org/10.3390/pr8060738.

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Alkyl lactates are green solvents that are successfully employed in several industries such as pharmaceutical, food and agricultural. They are considered prospective renewable substitutes for petroleum-derived solvents and the opportunity exists to obtain these valuable chemicals from the chemical recycling of waste poly(lactic acid). Alkyl lactates (ethyl lactate, propyl lactate and butyl lactate) were obtained from the catalysed alcoholysis reaction of poly(lactic acid) with the corresponding linear alcohol. Reactions were catalysed by a Zn complex synthesised from an ethylenediamine Schiff

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23

Pytela, Oldřich, and Zdeněk Bahník. "Synthesis, kinetics and mechanism of cyclization of 1-(2-aryloxycarbonylphenyl)-3-phenyltriazenes." Collection of Czechoslovak Chemical Communications 55, no. 11 (1990): 2692–700. http://dx.doi.org/10.1135/cccc19902692.

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Twelve substituted 1-(2-aryloxycarbonylphenyl)-3-phenyltriazenes have been synthetized and kinetics of their reactions have been measured in 52.1% (by mass) aqueous methanol at pH 3 to 11. Plots of kobs vs pH show three regions: noncatalyzed cyclization (pH 4 to 7), acid-catalyzed splitting of the triazene chain, and base-catalyzed cyclization. The non-catalyzed cyclization exhibits a kinetic isotope effect, the reaction constant ρ = 2.69 (σ-p), and β1g = 1.02, which indicates a mechanism of E1cB type with intramolecular proton transfer and a transient formation of a ketene intermediate. The b

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24

Zhao, Shunzheng, Honghong Yi, Xiaolong Tang, et al. "The Hydrolysis of Carbonyl Sulfide at Low Temperature: A Review." Scientific World Journal 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/739501.

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Catalytic hydrolysis technology of carbonyl sulfide (COS) at low temperature was reviewed, including the development of catalysts, reaction kinetics, and reaction mechanism of COS hydrolysis. It was indicated that the catalysts are mainly involved metal oxide and activated carbon. The active ingredients which can load on COS hydrolysis catalyst include alkali metal, alkaline earth metal, transition metal oxides, rare earth metal oxides, mixed metal oxides, and nanometal oxides. The catalytic hydrolysis of COS is a first-order reaction with respect to carbonyl sulfide, while the reaction order

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25

Ferdous, Kaniz, and Mohammad Rakib Uddin. "Biodiesel from Sesame oil: Base catalysed transesterification." International Journal of Engineering & Technology 1, no. 4 (2012): 420. http://dx.doi.org/10.14419/ijet.v1i4.335.

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A process for the production of methyl ester from Sesame oil containing 6.1% free fatty acid (FFA) for the use as a biodiesel was studied. These studies were carried out on transesterification reaction of Sesame oil with methanol to produce biodiesel. The reaction parameters such as Methanol/Oil molar ratio, catalyst concentration and reaction time were optimized for the production of sesame oil methyl ester (SOME). Conversion of triglyceride has been monitored from viscosity measurement and also by measuring produced glycerin concentration. Pseudo first order kinetic model has been proposed f

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26

Mindl, Jaromír, Jaromír Kaválek, Helena Straková, and Vojeslav Štěrba. "Kinetics of Base-Catalysed Hydrolysis and Cyclisation of Substituted Acetamide and Benzamide O-(Phenoxycarbonyl)oximes." Collection of Czechoslovak Chemical Communications 64, no. 10 (1999): 1641–53. http://dx.doi.org/10.1135/cccc19991641.

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The reaction kinetics of acetamide O-(4-nitrophenoxycarbonyl)oxime have been studied in aqueous buffers at pH 2-11. At pH > 9, the pH dependence of kobs is linear with slope 1, the cyclisation to 3-methyl-1,2,4-oxadiazol-5(4H)-one and 4-nitrophenol being the only reaction. At pH < 7.5, the only reaction is the hydrolysis giving 4-nitrophenol and acetamidoxime. The dependence of kobs on pH has been used to determine the rate equation and to propose the reaction mechanism. The cyclisation kinetics of substituted benzamide O-(phenoxycarbonyl)oximes have been studied in the pH range from 9.2

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27

Jadhav, Amarsinh L., and Ganapati D. Yadav. "A Green Process for Selective Hydrolysis of Cinnamaldehyde in Water to Natural Benzaldehyde by Using Ti and Zn Modified Hydrotalcites as Catalysts." Current Green Chemistry 6, no. 3 (2019): 242–54. http://dx.doi.org/10.2174/2213346106666191021105244.

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Hydrolysis of Cinnamaldehyde (CNM) is one of the important processes for the production of industrially essential natural benzaldehyde. Benzaldehyde is a vital precursor in the production of perfumes, cosmetics, food, beverages, and pharmaceutical intermediates. As homogeneous base catalysts are polluting and difficult to separate, heterogeneous catalysts should be used. Hydrolysis of cinnamaldehyde to benzaldehyde was studied over modified hydrotalcite (HT) base catalysts wherein HT was activated with either zinc or titanium, by combustion synthesis using glycine or glycerol as fuel. Both the

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Pytela, Oldřich, and Taťjana Nevěčná. "Kinetics and Mechanism of Decomposition of 1,3-Bis(4-methylphenyl)triazene Catalyzed with Substituted Benzoic Acids in 25% Aqueous Methanol-General or Specific Catalysis?" Collection of Czechoslovak Chemical Communications 59, no. 9 (1994): 2029–41. http://dx.doi.org/10.1135/cccc19942029.

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The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effe

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29

Warnasooriya, Chandani, and David Rueda. "Single-molecule fluorescence-based studies on the dynamics, assembly and catalytic mechanism of the spliceosome." Biochemical Society Transactions 42, no. 4 (2014): 1211–18. http://dx.doi.org/10.1042/bst20140105.

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Pre-mRNA (precursor mRNA) splicing is a key step in cellular gene expression where introns are excised and exons are ligated together to produce mature mRNA. This process is catalysed by the spliceosome, which consists of five snRNPs (small nuclear ribonucleoprotein particles) and numerous protein factors. Assembly of these snRNPs and associated proteins is a highly dynamic process, making it challenging to study the conformational rearrangements and spliceosome assembly kinetics in bulk studies. In the present review, we discuss recent studies utilizing techniques based on single-molecule det

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30

Shen, Zhaobing, Yejun Han, Yue Liu, et al. "Understanding Surface Basic Sites of Catalysts: Kinetics and Mechanism of Dehydrochlorination of 1,2-Dichloroethane over N-Doped Carbon Catalysts." Catalysts 10, no. 6 (2020): 707. http://dx.doi.org/10.3390/catal10060707.

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The production of vinyl chloride (VCM) by pyrolysis of 1,2-dichloroethane (DCE) is an important process in the ethylene-based poly(vinyl chloride) industry. The pyrolysis is performed at temperatures above 500 °C, gives low conversions, and has high energy consumption. We have shown that N-doped carbon catalysts give excellent performances in DCE dehydrochlorination at 280 °C. The current understanding of the active sites, mechanism, and kinetics of DCE dehydrochlorination over N-doped carbon catalysts is limited. Here, we showed that pyridinic-N on a N-doped carbon catalyst is the active site

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31

Tee, Oswald S., and N. Rani Iyengar. "Kinetics and mechanism of the bromination of phenols in aqueous solution. Evidence of general base catalysis of bromine attack." Canadian Journal of Chemistry 68, no. 10 (1990): 1769–73. http://dx.doi.org/10.1139/v90-275.

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The reactions of bromine with phenol, 4-bromophenol, and 4-methylphenol (p-cresol) in aqueous solution are catalyzed by carboxylate anions, confirming the suggestions of earlier work. The results are consistent with deprotonation of the phenol hydroxyl group by a general base occurring at more or less the same time as electrophilic attack by molecular bromine. Possible origins of the general base catalysis are discussed. Combined with earlier results, the present findings suggest that a protonated cyclohexadienone is not a mandatory intermediate in phenol bromination; it can be avoided in both

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32

ABBADI, Amine, Monika BRUMMEL, Burkhardt S. SCHüTT, Mary B. SLABAUGH, Ricardo SCHUCH, and Friedrich SPENER. "Reaction mechanism of recombinant 3-oxoacyl-(acyl-carrier-protein) synthase III from Cuphea wrightii embryo, a fatty acid synthase type II condensing enzyme." Biochemical Journal 345, no. 1 (1999): 153–60. http://dx.doi.org/10.1042/bj3450153.

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A unique feature of fatty acid synthase (FAS) type II of higher plants and bacteria is 3-oxoacyl-[acyl-carrier-protein (ACP)] synthase III (KAS III), which catalyses the committing condensing reaction. Working with KAS IIIs from Cuphea seeds we obtained kinetic evidence that KAS III catalysis follows a Ping-Pong mechanism and that these enzymes have substrate-binding sites for acetyl-CoA and malonyl-ACP. It was the aim of the present study to identify these binding sites and to elucidate the catalytic mechanism of recombinant Cuphea wrightii KAS III, which we expressed in Escherichia coli. We

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Dhavale, Dilip Dattatraya, Poonam Joshi, and Keshav Gangadhar Marathe. "Flavanoids. Part 6. The kinetics and mechanism of base-catalysed isomerisation of 3-arylideneflavanones." Journal of the Chemical Society, Perkin Transactions 2, no. 4 (1987): 449. http://dx.doi.org/10.1039/p29870000449.

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34

Asghar, Basim H. "Study of Kinetics, Equilibrium and the Influence of Steric Effects on Proton-Transfer in the Reactions of 2, 2, 4- and 2, 6- Substituted Anilines with 2-Phenoxy-3,5-dinitropyridine in DMSO." E-Journal of Chemistry 7, no. 1 (2010): 253–59. http://dx.doi.org/10.1155/2010/721387.

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Kinetic and equilibrium results for the reactions of 2-phenoxy-3,5-dinitropyridine (1), with a series of 2, 2, 4- and 2, 6- substituted anilines (2a-f), in the presence of DABCO in DMSO are reported. The reactions yield the 2-anilino derivatives (5), without the accumulation of intermediates. Kinetics studies are compatible with a two-step mechanism involving initial nucleophilic attack by amine at the ring carbon substituted by phenoxy group followed by either base-catalyzed or uncatalyzed conversion to the product. The base-catalyzed pathway is likely to involve rate-limiting proton-transfer

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35

Dubrovskii, Vladimir G. "Theory of MBE Growth of Nanowires on Adsorbing Substrates: The Role of the Shadowing Effect on the Diffusion Transport." Nanomaterials 12, no. 7 (2022): 1064. http://dx.doi.org/10.3390/nano12071064.

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A new model for nanowire growth by molecular beam epitaxy is proposed which extends the earlier approaches treating an isolated nanowire to the case of ensembles of nanowires. I consider an adsorbing substrate on which the arriving growth species (group III adatoms for III-V nanowires) may diffuse to the nanowire base and subsequently to the top without desorption. Analytical solution for the nanowire length evolution at a constant radius shows that the shadowing of the substrate surface is efficient and affects the growth kinetics from the very beginning of growth in dense enough ensembles of

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36

Azofra, Luis Miguel, Mai Anh Tran, Viktoriia Zubar, Luigi Cavallo, Magnus Rueping, and Osama El-Sepelgy. "Conversion of racemic alcohols to optically pure amine precursors enabled by catalyst dynamic kinetic resolution: experiment and computation." Chemical Communications 56, no. 64 (2020): 9094–97. http://dx.doi.org/10.1039/d0cc02881a.

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37

Zhou, Dan, Linlin Wang, Xiaopeng Chen, et al. "A novel acid catalyst based on super/subcritical CO 2 -enriched water for the efficient esterification of rosin." Royal Society Open Science 5, no. 7 (2018): 171031. http://dx.doi.org/10.1098/rsos.171031.

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Rosin esters are widely applied as masticatory substances and beverage stabilizers, while classical acid-catalysed processes will lead to metal residue or environmental issues. Super/subcritical CO 2 –enriched high temperature liquid water (HTLW) as a green acid catalyst in the esterification reaction of rosin with glycerol was investigated. The pH of CO 2 –H 2 O binary system, as calculated based on gas–liquid equilibrium, charge balance and chemical equilibrium equations, ranged from 3.49 to 3.70 depending on the reaction conditions, indicating effective acid catalysis. Response surface meth

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38

Shoukry, Azza, Mohamed Shoukry та Mohamed Hafez. "Kinetics of base hydrolysis of α-amino acid esters catalyzed by palladium(II) piperazine complex". Open Chemistry 8, № 4 (2010): 797–805. http://dx.doi.org/10.2478/s11532-010-0047-6.

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AbstractThe kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25°C, and I = 0.1 mol dm−3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane/water solutions of different compositions. The kinetic data are fit under the assumption that the hydrolysis proceeds in one step. The activation parameters for the base hydrolysis of the complexes are evaluated

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39

Tiwari, B. R., Md T. Noori, and M. M. Ghangrekar. "Enhancing performance of microbial fuel cell treating distillery wastewater using carbon supported Nickel-phthalocyanine/MnOx as novel cathode catalyst." MRS Advances 3, no. 13 (2018): 657–62. http://dx.doi.org/10.1557/adv.2018.73.

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ABSTRACTThree MFCs with different catalyst incorporated on carbon felt cathode, viz. nickel phthalocyanine-MnOx (NiPc-MnOx) composite (MFC-1), platinum (MFC-2), control MFC with bare carbon felt (MFC-3) were used for treating distillery wastewater. The linear sweep voltammetry studies revealed that a maximum current density of 3.7 Am-2 was achieved for NiPc-MnOx/C catalysed cathode, which is 13-folds higher than that for control cathode (0.27 Am-2). Consequently, MFC-1 demonstrated a power density of 48.8 mWm-2, which was around 3.3-folds higher than the control MFC (14.9 mWm-2) owing to the i

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40

Riyaz, Sayima, Ghulam Mustafa Peerzada, Nadeem Bashir Ganaie, and Usma Gull. "Kinetics of the Acetaminophen-Based Oscillatory Chemical Reaction with and without Ferroin as Catalyst: An Inorganic Prototype Model for Acetaminophen–Ethanol Syndrome." Progress in Reaction Kinetics and Mechanism 42, no. 2 (2017): 163–81. http://dx.doi.org/10.3184/146867817x14806858831901.

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This paper describes the nonlinear behaviour of the acetaminophen-based uncatalysed Belousov–Zhabotinsky oscillator and its dynamics in the presence of ferroin as catalyst. The role of free metal ions as catalysts was examined and the results compared with those of corresponding complexed catalysts. Free metal ions were found to be sluggish with respect to the evolution of the oscillatory regime as compared to complexed ones. The effect was monitored of change of the ligand moiety of the catalyst complex on the oscillatory parameters. Since ethanol potentiates the hepatotoxicity caused by acet

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41

Suleiman, Kamaluddeen Kabo, Yusha’u Auwal, and Abdullahi Haruna. "Influence of Structure and Base Modification of Zinc Oxide Nanostructures on Kinetic Parameters of the Transesterification of Rice Bran Oil to Biodiesel." UMYU Journal of Pure and Industrial Chemical Research 2, no. 2 (2022): 24–39. http://dx.doi.org/10.55688/ujpicr22.007.

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Biodiesel is an alternative to biofuel that could help to reduce the use of fossil fuels and protect the environment. Evaluation of reaction kinetics provides information on reaction rates and mechanism which is necessary in evaluating catalyst’s effectiveness. In this research, zinc oxide (ZnO) nanostructures, nanoparticles, nanoflowers and nanotubes were base-modified with potassium to enhance their active sites and used in the transesterification process for study of kinetic parameters. The nanocatalysts were characterized with FESEM and biodiesel conversion monitored with 1H NMR. The resul

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Fialová, Marie, Jindřich Zahradník, and Hana Kučerová. "Design of continuous flow immobilized bacterial cells reactor for production of L-malic acid." Collection of Czechoslovak Chemical Communications 55, no. 9 (1990): 2192–98. http://dx.doi.org/10.1135/cccc19902192.

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An experimental study was carried out, aimed at establishing an engineering data base for the optimum design of a pilot-plant fixed bed reactor for continuous biotransformation of natrium fumarate to L-malic acid catalysed by immobilized bacterial cells. Cells Corynebacterium sp. immobilized in calcium alginate were used for experiments. Effective reaction kinetics including the effect of transport phenomena in the bed was determined and conditions of the safe conversion data scale up were defined. Regarding the requirements of continuous production, long-term stability of the biocatalytic sys

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43

GONÇALVES, Olivier, Thierry DINTINGER, Jacques LEBRETON, Dominique BLANCHARD, and Charles TELLIER. "Mechanism of an antibody-catalysed allylic isomerization." Biochemical Journal 346, no. 3 (2000): 691–98. http://dx.doi.org/10.1042/bj3460691.

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The catalytic antibody 4B2, which was generated against a substituted amidine 1, catalyses the allylic isomerization of β,γ-unsaturated ketones with an acceleration factor (kcat/kuncat) of 1.5×103. On the basis of the ‘bait and switch’ strategy, it was reasoned that the positively charged hapten could elicit, by charge complementarity, an acidic residue (Asp or Glu) in the antibody-binding site in the right position to catalyse this proton transfer reaction. The pH dependence curve of kcat/Km shows a bell-shaped feature with an optimum at approx. pH 4.5. By cloning and sequencing the light and

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Shi, Huancong, Min Huang, Qiming Wu, et al. "Study of Catalytic CO2 Absorption and Desorption with Tertiary Amine DEEA and 1DMA-2P with the Aid of Solid Acid and Solid Alkaline Chemicals." Molecules 24, no. 6 (2019): 1009. http://dx.doi.org/10.3390/molecules24061009.

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Studies of catalytic CO2 absorption and desorption were completed in two well-performed tertiary amines: diethylmonoethanolamine (DEEA) and 1-dimethylamino-2-propanol (1DMA-2P), with the aid of CaCO3 and MgCO3 in the absorption process, and with the aid of γ-Al2O3 and H-ZSM-5 in the desorption process. The batch process was used for CO2 absorption with solid alkalis, and the recirculation process was used for CO2 desorption with solid acid catalysts. The CO2 equilibrium solubility and pKa were also measured at 293 K with results comparable to the literature. The catalytic tests discovered that

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45

Tatsumoto, Kuniyasu, Rabindra P. Reddy та Arthur E. Martell. "Pyridoxal and pyridoxal 5′-phosphate catalyzed β-deuteration of α-aminobutyric acid and homoserine. I. Metal-free systems". Canadian Journal of Chemistry 64, № 10 (1986): 2053–59. http://dx.doi.org/10.1139/v86-339.

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As the initial step in the investigation of metal ion- and vitamin B6-catalyzed, β, γ-elimination in α-amino acids, the pyridoxal-and pyridoxal 5′-phosphate-catalyzed β-deuteration of α-aminobutyric acid and homoserine in D2O in metal-free systems has been studied by nuclear magnetic resonance. The reaction kinetics of α-H, β-H, and 4′-CH exchange rates were measured by following the rates of deuteration of these positions. The kinetic data obtained for these reactions lead to a proposed mechanism for β-deuteration. The relative rates of the deuteration reactions observed, and the order in whi

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46

RIBEIRO, João Meireles, Juan LÓPEZ-GÓMEZ, José María VERGELES, et al. "Rat liver nucleotide pyrophosphatase/phosphodiesterase is an efficient adenylyl transferase." Biochemical Journal 346, no. 1 (2000): 25–31. http://dx.doi.org/10.1042/bj3460025.

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Rat liver nucleotide pyrophosphatase/phosphodiesterase I (NPP/PDE) catalysed efficiently the transfer of adenylate from ATP to alcohols (methanol, ethanol, propanol, ethylene glycol, glycerol, 2,2-dichloroethanol and glycerol 2-phosphate), which acted as adenylate acceptors competing with water with different efficiencies. NPP/PDE kinetics in alcohol/water mixtures were accounted for by rate equations for competitive substrates, modified to include alcohol negative co-operativity and, depending on the nature of the alcohol, enzyme denaturation by high alcohol concentrations or activation by lo

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47

Bauerová, Ingrid, and Miroslav Ludwig. "Substituent Effects on the Base-Catalysed Hydrolysis of Phenyl Esters of ortho-Substituted Benzoic Acids." Collection of Czechoslovak Chemical Communications 66, no. 5 (2001): 770–84. http://dx.doi.org/10.1135/cccc20010770.

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Fourteen model phenyl esters of 2-substituted benzoic acids were synthesised. Structures and purity of model compounds were confirmed by 1H and 13C NMR spectroscopy, as well as by HPLC and elemental analysis. Kinetics of base-catalysed hydrolysis of model phenyl esters occurring by the BAc2 mechanism were measured by UV spectrophotometry in 50% (v/v) aqueous dimethyl sulfoxide solutions at 25 °C under pseudo-first-order reaction conditions (c(NaOH) = 0.001-1.0 mol l-1). Linear relation between J-E and log kobs with the slope close to unity was found for all model compounds. Neither one-paramet

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48

Avramovic, Jelena, Olivera Stamenkovic, Zoran Todorovic, Miodrag Lazic, and Vlada Veljkovic. "Empirical modeling the ultrasound-assisted base-catalyzed sunflower oil methanolysis kinetics." Chemical Industry and Chemical Engineering Quarterly 18, no. 1 (2012): 115–27. http://dx.doi.org/10.2298/ciceq110705053a.

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The ultrasound-assisted sunflower oil methanolysis catalyzed by KOH was studied to define a simple empirical kinetic model useful for reactor design without complex computation. It was assumed that the neutralization of free fatty acids and the saponification reaction were negligible. The methanolysis process rate was observed to be controlled by the mass transfer limitation in the initial heterogeneous regime and by the chemical reaction in the later pseudo-homogeneous regime. The model involving the irreversible second-order kinetics was established and used for simulation of the triacylglyc

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49

Koh, Han Joong, Ji-Won Lee, Hai Whang Lee, and Ikchoon Lee. "Kinetics and mechanism of the aminolysis of ethyl aryl carbonates in acetonitrile." Canadian Journal of Chemistry 76, no. 6 (1998): 710–16. http://dx.doi.org/10.1139/v98-038.

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The aminolysis reactions of ethyl aryl carbonates with benzylamines in acetonitrile at 25.0°C are investigated. The base-catalyzed path, k2, disappears when strong nucleophiles (X = p-CH3O and p-CH3) react with a substrate activated by a strong nucleofuge (Z = p-NO2). The large magnitude of rho x (-1.7 to -2.5), rho z (3.4 to 4.3), and rho xz (1.4) values, and relatively large kH/kD (1.6 to 1.8) found for the uncatalyzed path (k1) can be accounted for in terms of a stepwise mechanism with rate-limiting expulsion of the phenoxide leaving group. The catalyzed process (k2) is characterized by the

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50

Manaenkov, Oleg, Yuriy Kosivtsov, Valentin Sapunov, et al. "Kinetic Modeling for the “One-Pot” Hydrogenolysis of Cellulose to Glycols over Ru@Fe3O4/Polymer Catalyst." Reactions 3, no. 1 (2021): 1–11. http://dx.doi.org/10.3390/reactions3010001.

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Despite numerous works devoted to the cellulose hydrogenolysis process, only some of them describe reaction kinetics. This is explained by the complexity of the process and the simultaneous behavior of different reactions. In this work, we present the results of the kinetic study of glucose hydrogenolysis into ethylene- and propylene glycols in the presence of Ru@Fe3O4/HPS catalyst as a part of the process of catalytic conversion of cellulose into glycols. The structure of the Ru-containing magnetically separable Ru@Fe3O4/HPS catalysts supported on the polymeric matrix of hypercrosslinked poly

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