840-65-3Relevant academic research and scientific papers
Preparation method of dimethyl 2, 6-naphthalate
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, (2021/06/02)
The invention discloses a preparation method of dimethyl 2, 6-naphthalate. Specifically, the preparation method of the dimethyl 2, 6-naphthalate disclosed by the invention comprises the following steps: carrying out esterification reaction on 2, 6-naphthalic acid and methanol under a pressurization condition in the presence of a catalyst, and filtering without further purification to obtain the dimethyl 2, 6-naphthalate, wherein the mass ratio of the methanol to the 2, 6-naphthalic acid is (3: 1)-(25: 1), the reaction temperature ranges from 100 DEG C to 150 DEG C. According to the preparation method disclosed by the invention, the operation is simplified, the yield of the dimethyl 2, 6-naphthalate is improved, and meanwhile, the purity of the dimethyl 2, 6-naphthalate is maintained.
A containing double (2-substituted-sulfonyl -1, 3, 4-oxadiazol-5-yl) heterocyclic compound and use thereof
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Paragraph 0102; 0103; 0104, (2017/01/19)
The invention belongs to the field of chemical engineering and pesticides, and particularly relates to a heterocyclic compound containing bis(2-substituted sulfonyl-1,3,4-oxadiazole-5-radical) and application thereof. The structure of the heterocyclic compound is shown in the specification. In a general formula, R is hydrogen, C1-C5 alkyl radicals, C1-C5 halogenated alkyl radicals, C2-C5 alkenyl, and ester, benzyl or substituted benzyl of C2-C5, and Z is hydrocarbyl or substituted hydrocarbon thereof, phenyl, substituted phenyl, biphenylyl, substituted biphenylyl, naphthyl, substituted naphthyl, diphenyl hydrocarbyl, substituted diphenyl hydrocarbyl, and diphenyl ether or substituted diphenyl ether. The heterocyclic compound has very good inhibitory activity on rhizoctonia solani, fusarium asiaticum, borrytis cinerea, physalospora piricala, helminthossporium oryzae, tobacco bacterial wilt and rice brown blotches, can be applied to prevention and control of plant diseases and has wide application prospect.
Primary coloured electrochromism of aromatic oxygen and sulfur diesters
Xu, Xiuhui,Webster, Richard D.
, p. 18100 - 18107 (2014/05/20)
Eleven aromatic diesters and thioic S,S′-diesters were synthesized and investigated using electrochemical (cyclic voltammetry and controlled potential electrolysis) and UV-vis spectroscopic techniques over a range of temperatures. Nine of the compounds exhibited vibrant colour changes from a colourless state in their neutral forms to brightly coloured upon one-electron electrochemical reduction in acetonitrile. The compounds were found to display either red, green or blue colours in their one-electron reduced states. The electrochromic properties of 3 of the compounds that displayed the most vibrant colour changes were examined in solution using a gold micro-mesh electrode laminated inside a polymer film.
Recycling polyethylene naphthalate containing materials in a process to produce diesters
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Page/Page column 8-9, (2008/06/13)
A process for preparing a dialkylester of a naphthalenedicarboxylic acid comprising directing a liquid phase reaction mixture comprising a low molecular weight alcohol, a naphthalenedicarboxylic acid, a dialkylester of a naphthalenedicarboxylic acid, and a polyethylene naphthalate containing material, at a given temperature and pressure through series arranged reaction zones and subsequently removing a product comprising a dialkylester formed by the reaction of the naphthalenedicarboxylic acid and the polyethylene naphthalate containing material with the low molecular weight alcohol from a reaction zone. This invention is also directed to a process for preparing a purified dialkylester of a naphthalenedicarboxylic acid comprising a series of crystallization and distillation steps, and combinations thereof.
Catalyst for carbonylating naphthalene mono- and disulfonates and process using said catalyst
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, (2008/06/13)
A cobalt based catalyst, and the method for preparing it, are disclosed. The catalyst is obtained from the reaction between NaCo(CO)4 and s-trichloro triazine and is advantageously used in the processes of carbonylation of naphthalene mono- and disulfonates in order to yield naphthalene esters and acids.
Catalyst for carbonylating naphthalene mono- and disulfonates and process using said catalyst
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, (2008/06/13)
A cobalt based catalyst, and the method for preparing it, are disclosed. The catalyst is obtained from the reaction between NaCo(CO)4 and s-trichloro triazine and is advantageously used in the processes of carbonylation of naphthalene mono- and disulfonates in order to yield naphthalene esters and acids.
Cobalt-catalyzed methoxycarbonylation of naphthalene mono- and di-sulfonates to naphthalene mono- and di-esters
Cometti, Giuseppe,vosel, Annick Du,Francalanci, Franco,Santi, Roberto,Cabri, Walter,Foa, Marco
, p. C13 - C14 (2007/10/02)
The methoxycarbonylation of naphthalene mono- and di-sulfonates under mild reaction conditions catalyzed by cobalt complexes generated in situ from either -/Me2SO4 or -/BrCH2COOEt is reported.
Intramolecular quenching of excited singlet states by stable nitroxyl radicals
Green,Simpson,Zhou,Ho,Blough
, p. 7337 - 7346 (2007/10/02)
Absorbance and steady-state and time-resolved fluorescence measurements were employed to examine the mechanism(s) of excited singlet state quenching by nitroxides in a series of nitroxide-fluorophore adducts. This work establishes the following: (1) the absorption and emission energies of the fluorophores are unaffected by the presence of the nitroxide substituent(s), and the residual emission that is observed from the adducts arises from the locally excited singlet of the fluorophore, not from charge recombination; (2) rate constants for intramolecular quenching by the nitroxides (k) are high (108-1010s-1) and decrease significantly with increasing nitroxide to fluorophore distance-however, relatively high rates of quenching (>108 s-1) are observed over distances as great as 12 ?; (3) F?rster energy transfer does not contribute significantly to the quenching due to the low values for the spectral overlap integrals; (4) the kq's do not increase proportionally to the solvent-dependent increases in the Dexter overlap integral, indicating that energy transfer by the Dexter mechanism is not responsible for the quenching; (5) the values of kq show no obvious correlation with the calculated free energies for photoinduced electron transfer, suggesting that this quenching pathway is also unimportant; (6) for hematoporphyrin-nitroxide adducts, which contain a fluorophore whose singlet energy is below that of the first excited state energy of the nitroxide (thus precluding energy transfer), significant rates of quenching are still observed; (7) for compounds with similar nitroxide-fluorophore distance, an approximately linear correlation is observed between the kq's of the paramagnetic compounds and the nonradiative rate constants of the diamagnetic reference compounds, suggesting that the nitroxide moiety catalyses a preexisting nonradiative pathway in the fluorophore. These results indicate that the quenching arises through electron exchange which causes relaxation of the (local) singlet state to the triplet and/or ground state of the fluorophore.
Sequential Acetalization-Pyrolysis of α-Acetylcinnamates and α-Acetylbenzalacetones. A Method for the Generation of 2-Carbonyl-Subsituted Naphthalenes
Zoeller, Joseph R.,Sumner, Charles E.
, p. 319 - 324 (2007/10/02)
Substituted 2-acetonaphthones and 2-naphthoate methyl esters can be generated from benzaldehydes in a sequence of three reaction steps.Knoevenagel condensation of a benzaldehyde with 2,4-pentandione of methyl acetoacetate yields α-carbonyl-substituted benzalacetones.The α-carbonyl-substituted benzalacetones are then cyclized to generate the α-carbonyl-substituted naphthalenes by a sequential acetalization with trimethyl orthoformate followed by subsequent pyrolysis of the dimethyl acetal either in the vapor phase at 475 deg C or by being heated in boiling 1-methylnaphthalene. 2-Acetonaphthones are obtained when 2,4-pentanedione is used and 2-naphthoate methyl esters are obtained from methyl acetoacetate.
Thermal Ring Annulation of α-Vinylcinnamate Methyl Esters. A Method for the Generation of 3,4-Dihydro-2-naphthoate and 2-Naphthoate Methyl Esters
Zoeller, Joseph R.
, p. 4716 - 4719 (2007/10/02)
Ring annulation of methyl-2-benzylidene-3-buten-1-oates (methyl α-vinylcinnamates) to generate a series of methyl 3,4-dihydro-2-naphthoates has been accomplished by a thermal reaction.The thermolysis is performed either in the vapor phase at 425 deg C or by heating the compound in a high-boiling solvent for an extended period of time.Regiochemistry is entirely predictible with para- and ortho-substituted methyl α-vinylcinnamates generating exclusively 6-substituted and 8-substituted 3,4-dihydro-2-naphthoates,respectively.Meta-substituted α-vinylcinnamates generate a mixture of 5-and 7-substituted 3,4-dihydro-2-naphthoates. 2-Naphthoate methyl esters can also be obtained by including a palladium on carbon catalyst in the liquid-phase version of this thermolysis.
