Chlorination of 2,4,6-trichlorophenol in acidic aqueous medium

1985 ◽  
Vol 50 (8) ◽  
pp. 1842-1851 ◽  
Author(s):  
Petr Švec
Keyword(s):  
Reaction Mechanism ◽  
Aqueous Medium ◽  
Hydrogen Chloride ◽  
Reaction Medium ◽  
Model Experiments ◽  
Sulfuric And Hydrochloric Acids

The course of chlorination of 2,4,6-trichlorophenol (I) in water and approximately 20% sulfuric and hydrochloric acids has been investigated. In all these media the reaction gives primarily 2,4,6,6-tetrachloro-2,4-cyclohexadienone (II) which is subsequently chlorinated under formation of polychlorinated alicyclic ketones or isomerized to give the more stable 2,4,6,6-tetrachloro-2,5-cyclohexadienone (III), the precursor of further arising chlorinated 1,4-benzoquinones. The ratio of the arising polychlorinated alicyclic ketones to chlorinated 1,4-benzoquinones is significantly influenced by concentration of hydrogen chloride in the reaction medium. On the basis of model experiments, the reaction mechanism of exhaustive chlorination of 2,4,6-trichlorophenol has been suggested.

scholarly journals The reaction mechanism of polyalcohol dehydration in hot pressurized water

2016 ◽  
Vol 18 (47) ◽  
pp. 32438-32447 ◽  
Author(s):  
Sergi Ruiz-Barragan ◽  
Jordi Ribas Ariño ◽  
Motoyuki Shiga
Keyword(s):  
High Temperature ◽  
Reaction Mechanism ◽  
Green Chemistry ◽  
Liquid Water ◽  
Reaction Medium ◽  
Pressurized Water ◽  
Promising Technology ◽  
Temperature Liquid

The use of high-temperature liquid water (HTW) as a reaction medium is a very promising technology in the field of green chemistry.

scholarly journals The reaction mechanism of the [2+3] cycloaddition between α-phenylnitroethene and (Z)-C,N-diphenylnitrone in the light of a B3LYP/6-31G(d) computational study

2013 ◽  
Vol 11 (3) ◽  
pp. 404-412 ◽  
Author(s):  
Radomir Jasiński ◽  
Maria Mikulska ◽  
Andrzej Barański
Keyword(s):  
Reaction Mechanism ◽  
Gas Phase ◽  
Computational Study ◽  
Reaction Medium ◽  
Reaction Pathways ◽  
Reactivity Indices ◽  
Polar Media ◽  
One Step ◽  
Step Mechanism

AbstractAbstract The analysis of reactivity indices suggests the polar nature of the [2+3] cycloaddition of a-phenylnitroethene to (Z)-C,N-diphenylnitrone. Similar conclusions can be drawn from the investigation of the reaction pathways using the B3LYP/6-31g(d) algorithm. This shows that the cycloaddition mechanism depends on the polarity of the reaction medium. A one-step mechanism is followed in the gas phase and toluene in all the theoretically possible pathways. In more polar media (nitromethane, water), a zwitterionic, two-step rather than a one-step mechanism occurs in the pathway leading to 3,4-trans-2,3,5-triphenyl-4-nitroisoxazolidine. Graphical abstract

Mono and Tri-cationic Imidazolium Salts: Use as Stabilizers for Silver Nanoparticles and Anticancer Study

2021 ◽  
Vol 6 (3) ◽  
pp. 167-174
Author(s):  
R. Rohini ◽  
N. Naresh Reddy ◽  
A. Sanjeev ◽  
S. Bhaskar ◽  
P. Muralidhar Reddy
Keyword(s):  
Silver Nanoparticles ◽  
Aqueous Medium ◽  
Chemical Reduction ◽  
Reaction Medium ◽  
Morphology Control ◽  
Medium Effect ◽  
Imidazolium Salts ◽  
Size And Morphology ◽  
Size And Morphology Control

In present strudy, the synthesis and characterization of monocationic 1,3-tetradecylimidazolium; [(C14)2Im]Br and tricationic benzene centered tris-tetradecyl/hexadecyl imidazolium bromide salts; i.e. [(C14)3C6H3Im]Br3 and [(C16)3C6H3ImBr]Br3 is reported. The stabilizer role of imidazolium salts to prepare silver nanoparticles (AgNPs) via chemical reduction method was investigated. To understand the reaction medium effect on the size and morphology control of AgNPs, monophasic (aqueous medium) and biphasic (DCM/H2O) approaches were applied. The morphology control was noticed for AgNPs protected with [(C14)3C6H3Im]Br3 (show sphere like morphology) and [(C14)2Im]Br (show dendritic structures) via biphasic approach. A clear variation in the size and morphology of AgNPs was noticed by varying the type of stabilizers and reaction medium. It was also observed that AgNPs were formed and stabilized only in aqueous medium in both approaches, thus it is assumed that AgNPs surfaces were protected by imidazolium salts with bilayer fashion. Anticancer activity of imidazolium salts was performed by MTT assay against HeLa cancer cell lines. The result shows that cytotoxic activity of tricationic [(C14)3C6H3Im]Br3 was more potent than that of monocationic [(C14)2Im]Br. The outcome suggests that there is an urgent need to develop new polycationic imidazolium salts for various chemical and medicinal applications.

Microwave-assisted C-C and C-heteroatom bond formations in aqueous medium

2021 ◽  
Vol 08 ◽  
Author(s):  
Bijeta Mitra ◽  
Pranab Ghosh
Keyword(s):  
Reaction Time ◽  
Aqueous Medium ◽  
Organic Synthesis ◽  
Bioactive Compounds ◽  
Bond Formation ◽  
Reaction Medium ◽  
Microwave Assisted ◽  
Reaction Condition ◽  
Mother Earth ◽  
Bond Formation Reactions

: In recent times, microwave assisted chemistry have gained enormous attraction in organic synthesis owing to its versatile advantages such as avoidance of harsh reaction condition, increase of yield, eliminates of by product, shorter reaction time and removal of wastages. Besides, water as a reaction medium further includes more benefit as it eliminates all the drawbacks of toxic solvent which may cause injuries for our mother earth. Furthermore C-C and C-heteroatom bond formation reactions are very significant as most of the drug as well as bioactive compounds contain heterocycles or C-hetero bond which is a key tool of chemistry. This article demonstrates the advancement on the topic of the microwave assisted C-C and C-heteroatom bond formation reactions in aqueous medium.

Cinétique d'oxydation des oximes du benzaldéhyde et de l'acétophénone par l'ion thallique

1980 ◽  
Vol 58 (13) ◽  
pp. 1305-1310 ◽  
Author(s):  
Robert Lortie ◽  
Miklos Zador
Keyword(s):  
Reaction Mechanism ◽  
Aqueous Medium ◽  
Rate Equation ◽  
Chloride Ions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation of benzaldehyde and acetophenone oximes by Tl(III) in aqueous medium has been studied. The reaction occurs in two consecutive steps: formation of a nitroso intermediate and its decomposition. The oxime forms a complex with Tl(III) leading to the rate equation: −d[oxime]/dt = K1/k2[oxime][Tl(III)]/(1 + K1[Tl(III)]). The formation of the final carbonyl product is inhibited by Tl(III), a resuit of the formation of a complex resistant to decomposition. Coordination of Tl(III) by chloride ions affects the rate of the above two steps. The reaction mechanism is discussed. [Journal translation]

ARYLATION DES QUINONES PAR LES SELS DE DIAZONIUM: VIII. SUR LES 3-ARYL-1,2-NAPHTOQUINONES

1966 ◽  
Vol 44 (21) ◽  
pp. 2563-2565 ◽  
Author(s):  
Jacques Asselin ◽  
Paul Brassard ◽  
Philibert L'ecuyer
Keyword(s):  
Reaction Mechanism ◽  
Reaction Medium

The arylation of 1,2-naphthoquinone by benzenediazonium salts, in contrast to previously published results, gave only 3-aryl-1,2-naphthoquinones with poor to fair yields. The best reaction medium has been sought and the implications of the results with regard to the reaction mechanism are discussed.

scholarly journals Synthesis of gold hydrosols in the presence of Na2EDTA

2019 ◽  
pp. 86-94 ◽  
Author(s):  
Gvidona P. Shevchenko ◽  
Victor A. Zhuravkov ◽  
Nikolaj P. Osipovich ◽  
Galina V. Shishko
Keyword(s):  
Aqueous Medium ◽  
Alkaline Medium ◽  
Formation Process ◽  
Reaction Medium ◽  
Reduction Process ◽  
Process Rate ◽  
Spherical Nanoparticles ◽  
Uniform Size ◽  
Hydroxo Complexes ◽  
Kinetic Inhibition

The possibility of  Na2EDTA applying as a reducing and stabilizing reagent in aqueous medium to obtain gold hydrosols from hydrogen tetrachloroaurate was studied. It was found that, depending on the pH of the reaction medium, both nanosized precipitates (~60 nm) and gold hydrosols, consisting of spherical nanoparticles of uniform size (12–15 nm), can be obtained. Stable gold sols are formed at pH ≥ 10.5. Sol formation process rate depends on the temperature and concentration of  Na2EDTA and increases with their increase. An electrochemical study of processes of  HAuCl4 reduction and Na2EDTA oxidation showed that the possibility of gold hydrosols formation in an alkaline medium is due to the kinetic inhibition of the reduction process of gold hydroxo complexes formed during this process.

Thermal Dehydrochlorination of Poly(vinyl chloride) in Syndiotactic Systems

1992 ◽  
Vol 57 (1) ◽  
pp. 93-106 ◽  
Author(s):  
Jaroslav Burda ◽  
Rudolf Lukáš
Keyword(s):  
Molecular Weight ◽  
Reaction Mechanism ◽  
Hydrogen Chloride ◽  
Vinyl Chloride ◽  
Quantum Chemical ◽  
Low Molecular Weight ◽  
Ionic Mechanism ◽  
Reaction Conditions ◽  
Poly Vinyl Chloride ◽  
Ionic Intermediates

The thermal dehydrochlorination of syndiotactic poly(vinyl chloride) sequences has been studied theoretically on low-molecular weight models ranging from vinyl chloride dimer to pentamer using the semiempirical quantum chemical MNDO method. Parameters obtained with saturated systems and their change caused by the proceeding elimination of hydrogen chloride accompanied by the formation of the corresponding unsaturated structures are discussed with respect to the repeated chloroallyl or α-chloropolyene activation of the dehydrochlorination process. The study of the assumed radical and ionic intermediates is used in discussing the reaction mechanism of dehydrochlorination, and the radical or ionic mechanism is supposed to be operative depending on the reaction conditions.

scholarly journals Radical Functionalization of Thioglycosides in Aqueous Medium

2020 ◽  
Author(s):  
Sarbjeet Kaur ◽  
dominic luciano ◽  
gaoyuan zhao ◽  
Ting Wang
Keyword(s):  
Visible Light ◽  
Aqueous Medium ◽  
Reaction Medium ◽  
Reaction Pathways ◽  
Buffer System ◽  
Ene Reaction ◽  
Thiyl Radicals ◽  
Disulfide Formation ◽  
Basic Reaction ◽  
Radical Functionalization

<p>A visible-light-mediated thiol-ene reaction is successfully operated in aqueous medium. Organic photoredox catalyst (9-mesityl-10-methylacridinum tetrafluoroborate) is used to initiate the radical process to generate thiyl radicals upon light irradiation. Two reaction pathways are discovered in different aqueous buffer system. Thiol-ene adduct is preferred in acidity reaction medium; while disulfide formation is found to be favored in basic reaction medium. Moreover, a visible-light-mediated modified Danishefsky-Wan desulfurization is used to convert thioglycoside to highly substituted tetrahydropyran ring.</p>

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