- Preparation method of 2, 6-dihydroxy naphthalene
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The invention relates to a preparation method of 2, 6-dihydroxy naphthalene. A grinding vacuum reactor is adopted as a reactor so that mixed alkali and 2, 6-naphthalene disulfonate can be fully contacted and reacted in a solid phase state, the mixed alkali does not need to be heated to a molten state, and the mixed alkali compounded by alkali metal hydroxide and magnesium oxide is adopted, the addition of magnesium oxide can activate sulfo groups, the sulfo groups can be replaced by OH- more easily, a low-energy rapid path is realized, the reaction temperature is greatly reduced, the generation of byproducts such as tar is greatly reduced, and the conversion rate and the yield are improved.
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Paragraph 0024-0037
(2021/02/10)
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- Method for preparing 2, 6-dihydroxy naphthalene by solid super base catalysis
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The invention relates to a method for preparing 2, 6-dihydroxy naphthalene by solid super base catalysis. A solid super base is adopted as a catalyst and has the alkaline strength of more than 40, sulfonic acid groups can be activated by adding zinc oxide and Zn to enable the sulfonic acid groups to be more easily replaced by OH-, a low-energy quick path is realized, the conversion rate and the yield are improved, a grinding vacuum reactor is used as a reactor, the alkali metal hydroxide and the 2, 6-naphthalene disulfonate can be in full contact reaction in a solid phase state, the alkali metal hydroxide does not need to be heated to a molten state, the reaction temperature is greatly reduced, and the generation of byproducts such as tar is greatly reduced.
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Paragraph 0025; 0028-0030; 0032-0034; 0036-0038; 0040
(2021/02/10)
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- Preparation process for synthesizing 2,6-dihydroxynaphthalene
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The invention discloses a preparation process for synthesizing 2,6-dihydroxynaphthalene. The preparation process comprises specific steps as follows: (1) in an autoclave, adding 33-34 parts of 2,6-naphthalenedisulfonic acid disodium salt, 12-18 parts of sodium hydroxide and 50-52 parts of water, performing stirring and heating to 280-320 DEG C, and performing stirring for reaction at the temperature for 8-10 hours; (2) stirring the solution obtained after the reaction in the step (1) and cooling the solution to the room temperature, adding sulfuric acid with concentration of 40%-60%, and performing neutralization reaction until PH being 0.5-2; (3) filtering a suspension from the step (2), transferring filtered solids to a container, adding 150-152 parts of hexane, 0.1-0.15 parts of a copper salt catalyst and 1-1.5 parts of a phase transfer catalyst, performing stirring and heating to 30-60 DEG C, adding 12-50 parts of an oxidant with concentration of 20%-30%, and continuing reaction at30-70 DEG C for 2-4 hours to obtain a 2,6-dihydroxynaphthalene solution. The preparation process has the advantages that salt-containing wastewater is reduced, dosage of sodium hydroxide and potassium hydroxide is reduced, and the yield is significantly increased.
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Paragraph 0020-0031
(2020/09/20)
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- The selective oxidation of substituted aromatic hydrocarbons and the observation of uncoupling via redox cycling during naphthalene oxidation by the CYP101B1 system
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The cytochrome P450 monooxygenase enzyme CYP101B1, from Novosphingobium aromaticivorans DSM12444, efficiently and selectively oxidised a range of naphthalene and biphenyl derivatives. Methyl substituted naphthalenes were better substrates than ethylnaphthalenes and naphthalene itself. The highest product formation activity for a singly substituted alkylnaphthalene was obtained with 2-methylnaphthalene. The oxidation of alkylnaphthalenes was regioselective for the benzylic methyl or methine C-H bonds. The products from 1- and 2-ethylnaphthalene oxidation were highly enantioselective with a single stereoisomer being generated in significant excess. The disubstituted substrate, 2,7-dimethylnaphthalene, had a higher product formation activity than either 1- and 2-methylnaphthalene. Methyl substituted biphenyls were also better substrates than biphenyl and had similar biocatalytic parameters to 1-methylnaphthalene. CYP101B1 catalysed oxidation of 2- and 3-methylbiphenyl was selective for attack at the methyl C-H bonds. The exception was the turnover of 4-methylbiphenyl which generated 4′-(4-methylphenyl)phenol as the major product (70%) with 4-biphenylmethanol making up the remainder. The drug molecule diclofenac was also regioselectively oxidised to 4′-hydroxydiclofenac by CYP101B1. The activity of the CYP101B1 system with naphthalene was more complex and the rate of NADH oxidation increased over time but very little product, 1-naphthol, was generated. Addition of samples of 1-naphthol and 2-naphthol and low concentrations of 1,4-naphthoquinone induced rapid NADH oxidation activity in the in vitro turnovers in both the presence and absence of the cytochrome P450 enzyme. Hydrogen peroxide was generated in these reactions in absence of the P450 enzymes demonstrating that the ferredoxin and ferredoxin reductase in combination with quinones from naphthol oxidation and oxygen can undergo redox cycling giving rise to a form of uncoupling of the reducing equivalents.
- Hall, Emma A.,Sarkar, Md Raihan,Bell, Stephen G.
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p. 1537 - 1548
(2017/06/05)
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- A 2,6-dihydroxynaphthalene synthetic method
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The invention discloses a synthetic method of 2,6 dihydroxy naphthalene, which comprises the following steps: placing 2,6 dihydroxy naphthalene in an alkali fusion pan, then a mixture of solid sodium hydroxide and nitrate is placed, Slowly heating to 150-170 DEG C, stirring, continuously heating to 320 DEG C, insulating for fusing alkali for 2.5-3.5 hours at 310-330 DEG C, then cooling to 200 DEG C, slowly dropping 450g of water for diluting, using a tri(octyl-decyl)amine solution for extracting 2,6-dihydroxy naphthalene, then acidifying the extracted 2, 6-dihydroxy naphthalene by sulfuric acid, and filtering and refining filter cake by an ethanol water mixed solvent to obtain 2,6-dihydroxy naphthalene. According to the synthetic method of 2,6-dihydroxy naphthalene, the used inorganic solvent is a mixture of potassium nitrate, sodium nitrite and sodium nitrate. According to the invention, viscosity of an alkali fusion material is low, fluidity is good, material can be uniformly mixed, and alkali fusion effect is good. In addition, under high temperature condition for alkali fusion, no decomposition problem of oxidation organic matter is generated, and no difficult separating problem is generated for the mixture.
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Paragraph 0029; 0031
(2016/12/12)
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- A convenient and efficient synthesis of 2,6-dihydroxynaphthalene
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A convenient synthesis of 2,6-dihydroxynaphthalene from 6-bromo-2-naphthol has been achieved with high overall yield (52%) and good purity (95.7%) based on the conversion of 6-(methoxymethoxy)-2-naphthaldehyde to 6- (methoxymethoxy)-2-naphthol formate by a Baeyer-Villiger oxidation- rearrangement. Compared with the reported methods, the reaction conditions are milder and the work-up of each step is much simpler. Moreover, 6-bromo-2-naphthol as the starting material for the synthesis is readily available.
- Cui, Jia-Hua,Li, Shao-Shun
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p. 675 - 677
(2013/02/23)
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- Demethylation of aromatic methyl ethers using ionic liquids under microwave irradiation
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An efficient demethylation reaction for aromatic methyl ethers has been developed. Deprotection reactions give high yields with butylpyridinium bromide under microwave irradiation. Basic and acidic functional groups are tolerated if the reaction is performed under acidic conditions.
- Passiniemi, Mikko,Myllymaeki, Mikko J.,Vuokko, Juha,Koskinen, Ari M.P.
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scheme or table
p. 48 - 52
(2012/04/10)
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- Photoarylation/alkylation of bromonaphthols
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The photochemistry of 6-bromo-2-naphthols has been studied in acetonitrile, aqueous acetonitrile, and isopropyl alcohol in the absence and in the presence of triethylamine by product distribution analysis, laser flash photolysis (LFP), fluorescence, phosp
- Pretali, Luca,Doria, Filippo,Verga, Daniela,Profumo, Antonella,Freccero, Mauro
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experimental part
p. 1034 - 1041
(2009/07/04)
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- Solvent and temperature effects in the free radical aerobic oxidation of alkyl and acyl aromatics catalysed by transition metal salts and N-hydroxyphthalimide: New processes for the synthesis of p-hydroxybenzoic acid, diphenols, and dienes for liquid crystals and cross-linked polymers
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The aerobic oxidation of 4,4′-diisopropyldiphenyl and 2,6-diisopropylnaphthalene, catalysed by N-hydroxyphthalimide and Co(II) salts, leads to the corresponding tertiary benzyl alcohols with high conversion and selectivity under mild conditions (temperature 30-60°C and atmospheric pressure). Solvent and temperature effects, as resulting from the pioneering work of C. Walling, and more recently from the conclusive resolution of K. U. Ingold and co-workers on a quantitative kinetic basis, strongly affect the selectivity of the aerobic oxidation. This is related to the ratio between the rate of β-scission of the alkoxyl radical, which leads to acetophenone derivatives, and the rate of hydrogen atom abstraction, leading to tertiary benzyl alcohols. These latter are efficiently converted either to diphenols for the production of liquid crystals, by reaction with H2O2, or to dienes, useful as cross-linking agents, by dehydration. The aerobic oxidation of p-hydroxyacetophenone catalysed by Mn(NO3)2 and Co(NO3)2 leads with high selectivity to p-hydroxybenzoic acid, a useful monomer for liquid crystals.
- Minisci, Francesco,Recupero, Francesco,Cecchetto, Andrea,Gambarotti, Cristian,Punta, Carlo,Paganelli, Roberto,Pedulli, Gian Franco,Fontana, Francesca
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p. 163 - 168
(2013/09/04)
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- Synthesis of naphthalenediols by aerobic oxidation of diisopropylnaphthalenes catalyzed by N-hydroxyphthalimide (NHPI)/α, α′-azobisisobutyronitrile (AIBN)
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Naphthalenediols were successfully synthesized in a one-pot reaction through the oxidation of diisopropylnaphthalenes with air catalyzed by N-hydroxyphthalimide (NHPI) combined with α,α′- azobisisobutyronitrile (AIBN) followed by decomposition with sulfuric acid. Thus, the oxidation of 2,6-diisopropylnaphthalene with air (20 atm) in the presence of AIBN (3 mol %) and NHPI (10 mol %) in CH3CN at 75°C for 21 h followed by treatment with 0.3 M H2SO4 gave 2,6-naphthalenediol in 92% yield.
- Aoki, Yasuhiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 199 - 202
(2007/10/03)
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- Process for functionalising a phenolic compound carrying an electron-donating group
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The invention concerns a method for functionalizing a phenolic compound bearing an electron-donor group, in said group para position, inter alia a method for the amidoalkylation of a phenolic compound bearing an electron-donor group, and more particularly, a phenolic compound bearing an electron-donor group preferably, in the hydroxyl group ortho position. The method for functionalizing in para position with respect to an electron-donor group carried by a phenolic compound is characterised in that the phenolic compound bearing an electron-donor group is subjected to the following steps: a first step which consists of protecting the hydroxyl group in the form of a sulphonic ester function; a second step which consists in reacting the protected phenolic compound with an electrophilic reagent; optionally, a third step deprotecting the hydroxyl group.
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- Recognition of dihydroxynaphthalenes by a C2-symmetric host
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A functionalized C2-symmetric host (2) shows high affinity and substrate selectivity for dihydroxynaphthalenes.
- Kim, Hae-Jo,Moon, Dohyun,Lah, Myoung Soo,Hong, Jong-In
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p. 1887 - 1890
(2007/10/03)
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- Polymer electrolyte and process for producing the same
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A polymer electrolyte having, in a main chain, a structural unit represented by the following formula (1):-[Ar1-(SO2-N-(X+)-SO2-Ar2)m-SO2-N-(X+)-SO2-Ar1-O]- wherein Ar1 and Ar2 independently represent a divalent aromatic groups, m represents an integer of 0 to 3, and X+ represents an ion selected from hydrogen ion, an alkali metal ion and ammonium ion, which is excellent in proton conductivity, thermal resistance and strength. The polymer electrolyte is soluble in solvents and has excellent film forming property and recycling efficiency.
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- Regioselective hydrolysis of diacetoxynaphthalenes catalyzed by Pseudomonas sp. lipase in an organic solvent
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Depending on the relative positions of the acetyl groups in the aromatic rings, the Pseudomonas sp. lipase-catalyzed hydrolysis of diacetoxynaphthalenes in tert-butylmethyl ether proceeds regioselectively to afford the corresponding monoacetates.
- Ciuffreda, Pierangela,Casati, Silvana,Santaniello, Enzo
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p. 317 - 321
(2007/10/03)
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- Para-hydroxyalkylation of hydroxylated aromatic compounds
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Hydroxylated aromatic compounds devoid of substituents in the para-position to the hydroxyl group thereof are para-hydroxyalkylated, e.g., into optionally substituted p-hydroxymandelic acid compounds, more particularly p-hydroxymandelic acid and 3-methoxy-p-hydroxymandelic acid, by condensing same with an organic carbonyl compound in the presence of a quaternary ammonium hydroxide.
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- Method for preparing aromatic bischloroformate compositions
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Bischloroformate oligomer compositions are prepared by passing phosgene into a heterogeneous aqueous-organic mixture containing at least one dihydroxyaromatic compound, with simultaneous introduction of a base at a rate to maintain a specific pH range and to produce a specific volume ratio of aqueous to organic phase. By this method, it is possible to employ a minimum amount of phosgene. The reaction may be conducted batchwise or continuously. The bischloroformate composition may be employed for the preparation of cyclic polycarbonate oligomers or linear polycarbonate, and linear polycarbonate formation may be integrated with bischloroformate composition formation in a batch or continuous process.
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- Process for oxidizing 2,6-diisopropylnaphthalene
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In a process for producing 2,6-dihydroxynaphthalene from 2,6-diisopropylnaphthalene, 2,6-diisopropylnaphthalene is oxidized in the presence of a specific proportion of a basic compound to hydroxylate or hydroperoxylate 2,6-diisopropylnaphthalene in a high conversion, and the resulting intermediate is then subjected to acid cleavage in the presence of hydrogen peroxide to produce 2,6-dihydroxynaphthalene in a high yield. The yield of 2,6-dihydroxynaphthalene increases by subjecting the reaction mixture containing the above intermediate to a purifying operation or dehydrating operation or adding acetone to it before it is submitted to the acid cleavage. 2,6-Dihydroxynaphthalene may be reacted with acetic anhydride to obtain 2,6-diacetoxynaphthalene.
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- Oxyfunctionalization of Hydrocarbons. 17. Acid-Dependent High Regioselectivity Hydroxylation of Naphthalene with Hydrogen Peroxide Giving 1- or 2-Naphthol
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The acid-catalyzed hydroxylation of naphthalene with 90percent hydrogen peroxide was investigated.Regioselectivity of the reaction depends on the acidity of the system and the solvent used.In anhydrous hydrogen fluoride or 70percent HF-30percent pyridine solution at -10 to +20 deg C 1-naphthol is the product formed in > 98percent selectivity.In contrast, 2-naphthol is obtained in hydroxylation in superacid (HF-BF3, HF-SbF5, HF-TaF5, FSO3H-SbF5) solution at -60 to -78 deg C in > 98percent selectivity.When 1-naphthol reacted under the latter conditions 1,5- and 1,7-dihydroxynaphthalene were obtained, while 2-naphthol gave 1,6-dihydroxynaphthalene (along with only minor amounts of 1,7-dihydroxynapthtalene).The mechanism of the reactions is discussed, contrasting electrophilic hydroxylation of naphthalene, giving predominantly 1-substitution, with reaction of protonated naphthalenes (i.e., naphthtalenium ions) with hydrogen peroxide.
- Olah, George A.,Keumi, Takashi,Lecoq, Jean Claud,Fung, Alexander P.,Olah, Judith A.
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p. 6148 - 6151
(2007/10/02)
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- Bischoloroformate preparation method with phosgene removal and monochloroformate conversion
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Aqueous bischloroformates are prepared by the reaction of a dihydroxyaromatic compound (e.g., bisphenol A) with phosgene in a substantially inert organic liquid (e.g., methylene chloride) and in the presence of an aqueous alkali metal or alkaline earth metal base, at a pH below about 8. After all solid dihydroxyaromatic compound has been consumed, the pH is raised to a higher value in the range of about 7-12, preferably 9-11, and maintained in said range until a major proportion of the unreacted phosgene has been hydrolyzed. At the same time, any monochloroformate in the product may be converted to bischloroformate.
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- Process for the preparation of alkyl-substituted phenols or naphthols
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Process for the preparation of alkyl-substituted phenols or naphthols by oxidizing the corresponding dialkylbenzenes or dialkylnaphthalenes, respectively, at elevated temperatures of, for example, 70° to 130° C. by means of oxygen or oxygen donors, in the absence of solvents and in the presence of an alkali metal salt or alkaline earth metal salt of an organic carboxylic acid having 5 to 14 carbon atoms, to give the corresponding 2,6-dialkylnaphthalene-or 1,4-dialkylphenyl monohydroperoxides and subsequently hydrolysing the latter in a customary manner. The process results in pure, easily isolatable products in a good yield. The products of the process according to the invention are valuable precursors and intermediates for, inter alia, dyes, plastics or pharmaceuticals.
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- Cyclic monocarbonate bishaloformates
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Cyclic monocarbonate bischloroformates are prepared by the reaction of a carbonyl halide such as phosgene with a bridged substituted resorcinol or hydroquinone such as bis(2,4-dihydroxy-3-methylphenyl)methane or bis(2,5-dihydroxy-3,4,6-trimethylphenyl)methane in the presence of aqueous alkali metal hydroxide. The cyclic monocarbonate bischloroformates may be used for the preparation of linear or cyclic polycarbonates containing cyclic carbonate structural units, which may in turn be converted to crosslinked polycarbonates.
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- Counterattack Reagents Sodium Trimethylsilanethiolate and Hexamethyldisilathiane in the Bis-O-demethylation of Aryl Methyl Ethers
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New methods were developed for removal of two methyl groups from aryl methyl ethers.Treatment of an aryl methyl ether containing two methoxy units (i. e., 1, 3, 5, 7, 9, 11, or 13) with ca. 2.5 equiv of Me3SiSNa in 1,3-dimethyl-2-imidazolidinone at 185 deg C in a sealed tube gave the corresponding aryl alcohol (i. e. 2, 4, 6, 8, 10, 12 or 14) in 78-96percent yields after aqueous workup.Also, Me3SiSSiMe3 was found useful for bis-O-demethylation of aromatic compounds containing one free hydroxyl group and two methoxy units (e. g., 11 and 13).Thus 11 and 13 reacted with 1.5 equiv of NaH and then with 1.5 equiv of Me3SiSSiMe3 at 185 deg C in a sealed tube to afford triols 13 (75percent) and 14 (72percent), respectively.In these bis-O-demethylations, Me3SiSNa and Me3SiSSiMe3 act as counterattack reagents.
- Hwu, Jih Ru,Tsay, Shwu-Chen
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p. 5987 - 5991
(2007/10/02)
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- Process for the preparation of 2,6-dihydroxynaphthalene
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Process for the preparation of 2,6-dihydroxynaphthalene from 2,6-dialkylnaphthalenes, which are dissolved in an inert solvent and are oxidized at temperatures from 50° to 150° C. by means of oxygen or oxygen donors, in the presence of an alkali metal salt or alkaline earth metal salt of an organic carboxylic acid having 5 to 14 carbon atoms, to give the corresponding 2,6-dialkylnaphthalene dihydroperoxides, and the latter are subsequently hydrolysed. The process results in pure, easily isolatable products in a good yield. The process products according to the invention are valuable intermediates for, inter alia, dyes, plastics, synthetic fibres, polymeric liquid crystals or pharmaceuticals.
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- Process for producing 2,6-dihydroxynaphthalene and 2,6-diacetoxynaphthalene
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Disclosed herein is a process for producing 2,6-dihydroxynaphthalene which comprises oxidizing 2,6-di(2-hydroxy-2-propyl)naphthalene in acetonitrile, 1,4-dioxane or a mixture thereof with hydrogen peroxide in the presence of an inorganic acid or a solid acid at a temperture in the range of room temperature to the boiling point of the solution of the 2,6-di(2-hydroxy-2-propyl)naphthalene in acetonitrile or 1,4-dioxane, the acetonitrile, 1,4-dioxane or a mixture thereof being used in an amount of 3 to 30 ml to one gram of the 2,6-di(2-hydroxy-2-propyl)naphthalene.
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- Processes for preparing hydroxynaphthalenes
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Disclosed in accordance with the present invention are processes for the preparation of hydroperoxides and/or carbinols by liquid phase oxidation of secondary alkyl-substituted naphthalenes with molecular oxygen, wherein the oxidation reaction is carried out by dissolving in the reaction mixture containing the secondary alkyl-substituted naphthalenes at least 0.5 ppm in terms of metal, based on the starting secondary alkyl-substituted naphthalenes, of at least one compound of metal selected from the group consisting of palladium and gold, said metal compound being soluble in the reaction mixture of the secondary alkyl-substituted naphthalenes. When compared with the prior art processes using catalysts of non-homogeneous system, therefore, not only the amount of catalyst used can be minimized but also the rate of oxidation can be enhanced, and hence there can be obtained in a short period of time hydroperoxides and/or carbinols in high yields which are the oxidation products in accordance with the present invention. According to the present invention, the desired hydroperoxide can be obtained in high yields as well as in high purity from the hydroperoxides and/or carbinols obtained in the manner as mentioned above.
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- Polyetherimide bisphenol compositions
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Polyetherimide bisphenols and bischloroformates are prepared by the reaction of dianhydrides or certain bisimides with aminophenols or mixtures thereof with diamines. They are useful as intermediates for the preparation of cyclic heterocarbonates, which may in turn be converted to linear copolycarbonates. The bisphenols can also be converted to salts which react with cyclic polycarbonate oligomers to form block copolyetherimidecarbonates.
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- HYDROXYLATION DES NAPHTOLS EN MILIEU SUPERACIDE
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Hydroxylation of α and β naphtols by hydrogen peroxide in SbF5-HF occurs selectively on the non-phenolic ring, the electrophile reacting on the C-protonated substrate.
- Jacquesy, Jean-Claude,Jouannetaud, Marie-Paule,Morellet, Guy
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p. 3099 - 3102
(2007/10/02)
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- Method for preparing adduct of butadiene polymer or copolymer and α, β-ethylenically unsaturated dicarboxylic acid compound
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In a method for preparing an adduct of (A) a butadiene lower polymer or butadiene lower copolymer and (B) a α,β-ethylenically unsaturated dicarboxylic acid compound, said method is characterized in that said (A) and (B) are caused to react in the presence of one or more compounds selected from (C) p-phenylenediamine derivatives, catechol derivatives, pyrogallol derivatives, N-nitrosamines, quinoline derivatives and naphthol derivatives, thus serious increase of the viscosity of said adduct in the addition reaction can be prevented.
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