Results 11 to 20 of about 5,105,997 (296)

DFT Calculation of the Mechanism of the Acid-Catalyzed Aldol Condensation of a Lubricant Base Stock

Lubricants, 2023
Aldehyde condensation is a reaction step in the oxidization of a lubricant base stock into high-molecular-weight products, forming sludge and a paint film, which lead to the failure of lubricating oil.
Yan Li, Lei Xia, Rendong Liu
doaj   +1 more source

Synthesis of pure monetite by heterogeneous acid-base reaction

Revista Colombiana de Química, 2017
Five variations of the monetite (M) synthesis were evaluated modifying the stirring, the phosphoric acid addition rate, the homogeneity and the drying temperature. Products were assessed by means of XRD, FTIR, SEM-EDS analysis and chemical assay of Ca/P (
Luis Carlos Moreno Aldana, Davier Olarte Cárdenas, Edgar Delgado Mejía   +2 more
doaj   +1 more source

Synthesis of SO₄^2–/ZrO₂ Solid Acid and Na₂O/ZrO₂ Solid Base Catalysts Using Hydrothermal Method for Biodiesel Production from Low-Grade Crude Palm Oil

Indonesian Journal of Chemistry, 2022
Biodiesel is a renewable energy source that can be produced through esterification as well as transesterification reactions. This work presents a series of zirconia catalysts synthesized by hydrothermal method on various concentrations in acidic (H2SO4 0.
Sri Setyaningsih, Maisari Utami, Akhmad Syoufian, Eddy Heraldy, Nasih Widya Yuwono, Karna Wijaya   +5 more
doaj   +1 more source

KINETICS AND MECHANISMS OF THE ACID-BASE REACTION BETWEEN NH3 AND HCOOH IN INTERSTELLAR ICE ANALOGS [PDF]

, 2016
Interstellar complex organic molecules are commonly observed during star formation, and are proposed to form through radical chemistry in icy grain mantles.
J. Bergner, K. Öberg, M. Rajappan, E. Fayolle   +3 more
semanticscholar   +1 more source

Propriedades relacionadas à acidez e basicidade a partir da abordagem em química computacional

Química Nova, 2014
Analytical Chemistry books lack a clear link between thermodynamic and equilibrium approaches involving acids and bases. In this work, theoretical calculations were performed to search for these relations.
Sérgio R. B. Silva, Caio L. Firme, Kássio M. G. Lima   +2 more
doaj   +1 more source

Comparison of three methods for rendering plant fat transesterification

Research in Agricultural Engineering, 2013
Three most frequently used methods for fat transesterification were compared using rendering plant fat (RPF) as model. Acid-catalysed transesterification was found to be the most effective (conversion 90%) at optimum conditions (fat: methanol ratio 1:10,
A. Prošková, J. Kučera, Z. Kopicová, L. Škarková   +3 more
doaj   +1 more source

Evaluation of the influence of base and alkyl bromide on synthesis of pyrazinoic acid esters through fatorial design

Química Nova, 2009
Pyrazinoic acid esters have been synthesized as prodrugs of pyrazinoic acid. In the literature, its preparation is reported through the reaction of pyrazinoyl chloride with alcohols and the reaction with DCC/DMAP.
João Paulo dos Santos Fernandes, Veni Maria Andres Felli   +1 more
doaj   +1 more source

Acid/Base-Steered Cascade Cyclization: An Efficient One-Pot Access to Diverse Isobenzofuranone and Isoindolobenzoxazinone Derivatives

Molecules, 2023
We herein report the acid/base-steered two distinct reaction pathways of 2-acylbenzoic acids with isatoic anhydrides. In the presence of Na2CO3, the cascade process consists of the cyclization of 2-acetylbenzoic acid and nucleophilic ring-opening ...
Ran Shi, Xiangmin Wang, Xuesi Zhang, Sen Chen, Zu-Li Wang, Huijing Qi, Xin-Ming Xu   +6 more
doaj   +1 more source

Reações ácido-base: conceito, representação e generalização a partir das energias envolvidas nas transformações

Química Nova, 2012
Undergraduate students on the first year of Chemistry Courses are unfamiliar with the representation of acid-base reactions using the ionic equation H+ + OH- → H2O.
Iêda Aparecida Pastre, Lídia Maria de Almeida Plicas, Vera Aparecida de Oliveira Tiera, Juliana Vieira Custódio, Silvia Maria Leite Agostinho   +4 more
doaj   +1 more source

Ultrasonic Assisted Synthesis, Characterization and Bioactivity Assessment of Novel Piperonal Based Schiff Base and Its Metal Complexes [PDF]

Iranian Journal of Chemistry & Chemical Engineering, 2020
A novel Schiff base was synthesized by the reaction of piperonal and anthranilic acid, which was further utilized in the synthesis of five novel complexes by reaction with different metal salts ultrasonically.
Obaid-Ur-Rahman Abid, Aziz Ahmad, Wajid Rehman, Rehmat Zaman, Mohsin Ali, Sadullah Mir, Muhammad Qureshi Tauseef   +6 more
doaj   +1 more source