120-80-9Relevant articles and documents
Titanium Substitution in Silicon-free Molecular Sieves: Anatase-free TAPO4-5 and TAPO4-11 Synthesis and Characterisation for Hydroxylation of Phenol
Ulagappan, N.,Krishnasamy, V.
, p. 373 - 374 (1995)
Titanium-substituted ALPO4-5 and ALPO4-11 are synthesised using a modified procedure; they catalyse the hydroxylation of phenol to the extent of ca. 32percent, with good selectivity to catechol.
Synthesis of methyl 1-hydroxy-6-oxo-2-cyclohexenecarboxylate, a component of salicortin and tremulacin, and the monomer of idesolide
Richardson, Amie M.,Chen, Chun-Hsing,Snider, Barry B.
, p. 8099 - 8102 (2007)
(Chemical Equation Presented) We have developed a short and practical first synthesis of methyl 1-hydroxy-6-oxo-2-cyclohexenecarboxylate (2), which has been known as a component of salicortin and tremulacin since 1970. Birch reduction of the SEM ether of methyl salicylate followed by oxidation of the intermediate enolate with (-)-camphorsulfonyloxaziridine afforded the SEM enol ether of 2. Hydrolysis of the SEM enol ether afforded 2. We did not observe the dimerization of either racemic or optically enriched 2 to give idesolide (1).
New hydrotalcite-like anionic clays containing Zr4+ in the layers
Velu,Ramaswamy, Veda,Ramani,Chanda, Bhanu M.,Sivasanker
, p. 2107 - 2108 (1997)
New hydrotalcite-like anionic clays containing Zr4+ in the brucite-like layers are synthesised by a simple coprecipitation technique; these materials show very interesting properties as catalysts for liquid-phase hydroxylation of phenol with H2O2.
An iron-based micropore-enriched silica catalyst:: In situ confining of Fe2O3 in the mesopores and its improved catalytic properties
Long, Saifu,Zhou, Shijian,Yang, Fu,Lu, Kangchao,Xi, Tao,Kong, Yan
, p. 76064 - 76074 (2016)
Surface exposed catalytic active species are thought to be responsible for overall catalytic activity and selectivity. In this paper, controllable contents of iron oxides were in situ introduced into the inner surface of anionic surfactant-templated mesop
Flavoenzyme-mediated Regioselective Aromatic Hydroxylation with Coenzyme Biomimetics
Guarneri, Alice,Westphal, Adrie H.,Leertouwer, Jos,Lunsonga, Joy,Franssen, Maurice C. R.,Opperman, Diederik J.,Hollmann, Frank,van Berkel, Willem J. H.,Paul, Caroline E.
, p. 1368 - 1375 (2020)
Regioselective aromatic hydroxylation is desirable for the production of valuable compounds. External flavin-containing monooxygenases activate and selectively incorporate an oxygen atom in phenolic compounds through flavin reduction by the nicotinamide adenine dinucleotide coenzyme, and subsequent reaction with molecular oxygen. This study provides the proof of principle of flavoenzyme-catalyzed selective aromatic hydroxylation with coenzyme biomimetics. The carbamoylmethyl-substituted biomimetic in particular affords full conversion in less than two hours for the selective hydroxylation of 5 mM 3- and 4-hydroxybenzoates, displaying similar rates as with NADH, achieving a 10 mM/h enzymatic conversion of the medicinal product gentisate. This biomimetic appears to generate less uncoupling of hydroxylation that typically leads to undesired hydrogen peroxide. Therefore, we show these flavoenzymes have the potential to be applied in combination with biomimetics.
Heterogeneous Nitrogen-doped Graphene Catalysed HOO? Generation via a Non-radical Mechanism for Base-free Dakin Reaction
Sun, Wei,Gao, Lingfeng,Sun, Xu,Yang, Hua,Zheng, Gengxiu
, p. 5210 - 5216 (2019)
A heterogeneous nitrogen-doped graphene catalytic pathway for H2O2 activation to generate alkaline hydrogen peroxide (HOO?) through a non-radical mechanism was reported. Remarkably, the heterogeneous catalytic procedure has been used for the evergreen and environmentally Dakin reaction without using any transition metals, homogeneous bases, ligands, additives or promoters, completely. The study of catalyst structure and catalytic activities indicate that the most active sites are created by the graphitic N atoms at zig-zag edges of the sheets. In addition, N as dopant element changes the reactivity of the neighbour C atoms, and leads to the formation of carbon-hydroperoxide (C?(HOOH)) and C?O* (C?O?) transition state species on the graphene surface in catalytic the reaction. (Figure presented.).
Electrochemical oxidation of catechol in the presence of cyclopentadiene. Investigation of electrochemically induced Diels-Alder reactions
Nematollahi, Davood,Workentin, Mark S.,Tammari, Esmail
, p. 1631 - 1633 (2006)
We describe the synthesis and kinetic evaluation of compounds from [4 + 2] alone and [4 + 2] followed by [2 + 2] cycloaddition reactions of electrochemically generated o-benzoquinone with 1,3-cyclopentadiene. The Royal Society of Chemistry 2006.
Application of advanced oxidation processes for removing salicylic acid from synthetic wastewaters
Chen, Xue Ming,da Silva, Djalma Ribeiro,Martínez-Huitle, Carlos A.
, p. 101 - 104 (2010)
In this study, advanced oxidation processes (AOPs) such as anodic oxidation (AO), UV/H2O2 and Fenton processes (FP) were investigated for the degradation of salicylic acid (SA) in lab-scale experiments. Boron-doped diamond (BDD) film electrodes using Ta as substrates were employed for AO of SA. In the case of FP and UV/H2O2, most favorable experimental conditions were determined for each process and these were used for comparing with AO process. The study showed that the FP was the most effective process under acidic conditions, leading to the highest rate of SA degradation in a very short time interval. However, the results showed that Ta/BDD films had high electrocatalytic activity for complete degradation of SA; even if it employs more time for complete elimination of the SA respect to FP. Additionally, AO led to a sixfold acceleration of the oxidation rate compared with the UV/H2O2 process. Finally a rough comparison of the specific energy consumption shows that AO process reduced the energy consumption by at least 90% compared with the UV/H2O2 process.
Synthesis and catalytic properties of multilayered MEL-type titanosilicate nanosheets
Chen, Hong Li,Li, Shang Wei,Wang, Yi Meng
, p. 5889 - 5900 (2015)
Multilayered MEL-type titanosilicate nanosheets (MTS-2) were hydrothermally synthesized through a dual-template method, using cetyltrimethylammonium tosylate (CTATos) and tetrabutylammonium hydroxide (TBAOH) as templates for mesopores and micropores, resp
Mechanistic investigations in ultrasound-assisted biodegradation of phenanthrene
Kashyap, Niharika,Roy, Kuldeep,Moholkar, Vijayanand S.
, (2020)
This study has addressed the biodegradation of polycyclic aromatic hydrocarbon, phenanthrene using Candida tropicalis. Optimization using central composite statistical design yielded optimum experimental parameters as: pH = 6.2, temperature = 33.4 °C, mechanical shaking = 190 rpm and % inoculum = 9.26% v/v. Sonication of biodegradation mixture at 33 kHz and 10% duty cycle in log phase (12 h per day for 4 days) resulted in a 25% enhancement in phenanthrene removal. Profiles of specific growth rate (μ) and specific degradation rate (q) versus initial substrate concentration were fitted to Haldane substrate inhibition model. Both μ and q showed maxima for initial concentration of 100 mg L?1. Kinetic analysis of degradation profiles showed higher biomass yield coefficient and smaller decay coefficient in presence of sonication. Expression of total intracellular proteins in control and test experiments were analyzed using SDS–PAGE. This analysis revealed overexpression of enzyme catechol 2,3-dioxygenase (in meta route metabolism) during sonication which is involved in ring cleavage of phenanthrene. Evaluation of cell viability after sonication by flow cytometry analysis revealed > 80% live cells. These effects are attributed to enhanced cellular transport induced by intense microturbulence generated by sonication.
