- Synthesis method of 4-hydroxy-2,2-dimethyl-1,3-benzodioxole
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The invention discloses a synthetic method of 4-hydroxy-2,2-dimethyl-1,3-benzodioxole. The method comprises the following steps: using pyrogallic acid and 2-methoxy propylene as raw materials and toluene or xylene as a solvent, reacting at 110-135 DEG C, carrying out gas-phase separation to separate the byproduct methanol from the entrained solvent in the reaction process, carrying out condensation recovery on the separated methanol, returning the separated solvent to the reaction system, and completing the reaction to obtain the 4-hydroxy-2,2-dimethyl-1,3-benzodioxole. The content of the product reaches 99.0%-99.6%, and the yield reaches 88.1%-90.5%. The synthesis method disclosed by the invention is simple to operate and high in reaction selectivity, 50% of byproduct methanol is reducedfrom the source, the impurity generation probability is reduced, the amount of three wastes is greatly reduced, and the synthesis cost is greatly reduced.
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Paragraph 0028-0045
(2021/02/10)
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- Preparation method of bendiocarb intermediate and active ingredient
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The invention discloses a preparation method of a bendiocarb intermediate and an active ingredient. The preparation method includes: allowing pyrogallic acid to react with 2, 2-dimethoxypropane to generate a 2, 2-dimethyl-4-hydroxyl-1, 3-benzodioxoles solution, and directly using light components 2, 2-dimethoxypropane, 2-methoxypropene and methanol which are evaporated out for next batch after alkali washing; allowing the 2, 2-dimethyl-4-hydroxyl-1, 3-benzodioxoles solution to react with methyl isocyanate to obtain the bendiocarb active ingredient. By recycling raw materials and byproducts, cost is lowered, operation is simplified, production efficiency is improved, and convenience is brought for industrial production.
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Paragraph 0021; 0023; 0025; 0027; 0029; 0031
(2019/08/07)
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- 4-hydroxy -2,2-dimethyl -1,3-benzodioxan method for preparing wicked cyclopentadiene
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The invention discloses a preparation method of 4-hydroxy-2,2-dimethyl-1,3-benzodioxole (called dioxole for short). According to the preparation method, pyrogallic acid and 2,2-dimethoxy propane are taken as raw materials, methyl benzene or dimethyl benzene is taken as a reaction solvent, methanesulfonic acid dry resin is taken as a catalyst, a rectifying catalytic reaction mode is adopted, and the catalyst is arranged at the bottom of a rectifying tower positioned between a reaction kettle and a condenser; by-products methoxyl propylene and methanol which are generated through reaction are reacted under the action of the catalyst when passing through the rectifying tower to generate the raw material 2,2-dimethoxy propane, and the 2,2-dimethoxy propane is returned to the reaction kettle to participate in the reaction for preparing the dioxole again; surplus by-product methanol is transferred from the condenser positioned on the top of the rectifying tower, and a product is obtained from a tower kettle. The preparation method disclosed by the invention is simple in technological operation and high in reaction selectivity, and can be used for promoting the reaction equilibrium to move towards a target product direction, thus achieving the effects of low material consumption, high transformation rate and high selectivity; in addition, reaction liquid obtained through synthesis can be used for synthesis of active compound bendiocarb, no three wastes are basically generated and industrialized production is facilitated.
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Paragraph 0014
(2017/03/18)
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- Competitive degradation and detoxification of carbamate insecticides by membrane anodic fenton treatment
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The competitive degradation of six carbamate insecticides by membrane anodic Fenton treatment (AFT), a new Fenton treatment technology, was carried out in this study. The carbamates studied were dioxacarb, carbaryl, fenobucarb, promecarb, bendiocarb, and carbofuran. The results indicate that AFT can effectively degrade these insecticides in both single component and multicomponent systems. The carbamates compete for hydroxyl radicals, and their kinetics obey the previously developed AFT kinetic model quite well. Hydroxyl radical reaction rate constants were obtained, and they decrease in the following order: dioxacarb ≈ carbaryl > fenobucarb > promecarb > bendiocarb > carbofuran. The AFT is shown to have higher treatment efficiency at higher temperature. Degradation products of the carbamates were determined by gas chromatography/mass spectrometry, and it appears that degradation can be initiated by hydroxyl radical attack at different sites in the molecule, depending on the individual structure of the compound. Substituted phenols are the commonly seen degradation products. The AFT treatment can efficiently remove the chemical oxygen demand of the carbamate mixture, significantly increasing the biodegradability. Earthworm studies show that the AFT is also an effective detoxification process.
- Wang, Qiquan,Lemley, Ann T.
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p. 5382 - 5390
(2007/10/03)
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- 99mTc Complexes with Hexadentate Tricatechol Ligands
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The tricatechol ligand trisamine hydrochloride, TRIPACE (9), is prepared from tris(3-chloropropyl)amine (5) and the potassium salt of 2,2-dimethyl-1,3-benzodioxol-4-ol (7).This ligand is capable of reducing the 99m- ion to lower valent 99mTc and subsequent complexation of the reduced 99mTc ion.The structures of 5 and of trisamine (8) are determined by X-ray diffration.
- Hahn, Ekkehardt F.,Rupprecht, Stefan
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p. 481 - 486
(2007/10/02)
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- Aromatic urea derivatives and their use as herbicide
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This invention relates to novel compounds of formula [I], a process for their production, and their use as a herbicide. STR1 wherein A represents the bond STR2 in which X is a hydrogen atom, a chlorine atom, a nitro group or a trifluoromethyl group; B represents a hydrogen atom, a methyl group or a methoxy group; and Ar represents one member selected from the group consisting of STR3 in which R1 to R38, are as defined hereinafter.
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- Preparation of 2-substituted-1,3-dioxacycloalkanes from diols and diunsaturated ethers
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2-Substituted-1,3-dioxacycloalkanes (also known as acetonides) (such as STR1 (4-hydroxy-2,2-dimethyl-1,3-benzodioxole)) are prepared by reacting a diol (such as 1,2,3-trihydroxybenzene) and a diunsaturated ether (such as diisopropenyl ether). The reaction is exothermic and produces a ketone as the only by-product. The invention has utility in hydroxyl moiety "protection" and in pesticide synthesis.
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- Process for the production of N-methylcarbamates
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Process for the production of N-methylcarbamates: STR1 (wherein RO- is the radical of a substituted phenol or of a naphthol), wherein: in a first reaction step methylamine and diphenyl carbonate are reacted with each other, operating in the liquid phase and as a continuous process, in order to form phenol and phenyl-N-methylurethane; in a second reaction step phenyl-N-methylurethane, within the related reaction mixture outcoming from the first step, is thermally continuously decomposed, to yield a gaseous stream containing methyl isocyanate, from which the components different than methyl isocyanate are condensed off; in a third step the methyl isocyanate stream, outcoming from the second step, after an optional preliminary condensation, is continuously fed and contacted with a solution of a substituted phenol or of a naphthol in an inert organic solvent, containing a basic catalyst, to form N-methylcarbamate (I); N-methylcarbamate (I) is finally recovered from the reaction mixture outcoming from the third step.
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- Chinone von Benzo- und Dibenzokronenethern
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The preparation of the 1,4-quinones of benzocrown-5 (1), benzocrown-6 (2), and dibenzocrown-6 (3) and their quinols is described.The quinones are obtained by Fremy salt oxidation of the corresponding 3-hydroxybenzo-crown ethers which are readily accessible by a double protective group synthesis from 1,2,3-trihydroxybenzene.The synthetic pathway also provides a general high yield preparation of 2,3-dialkoxy-1,4-benzoquinones.The new crown ethers are characterised by 1H- and 13C-N.M.R. as well as U.V. spectroscopy.Non-aqueous redox potentials aredetermined by cyclic voltammetry.Crystalline complexes of 1 and 2 with various ammonium, alkali, and alkaline earth cations are also described.
- Dietl, F.,Gierer, G.,Merz, A.
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p. 626 - 631
(2007/10/02)
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- Process for preparing a 4-hydroxy-benzodioxol
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4-Hydroxy-benzodioxoles of formula STR1 in which R1 and R2 are alkyl of 1 to 4 carbon atoms or together represent an alkylene chain of 5 to 7 carbon atoms, which can be converted to pesticides, e.g. by reaction with methyl isocyanate, are prepared by reacting pyrogallol with a ketal of formula STR2 in which R3 and R4 are alkyl of 1 to 4 carbon atoms, at at least 90° C.
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- Benzodioxole derivatives useful as pesticides
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Substituted benzodioxoles of the formula: EQU1 wherein R1 and R2 are hydrogen or alkyl of 1 to 6 carbon atoms or together with the linking carbon atom form a cycloalkane or cycloalkene ring of 5 to 7 carbon atoms; R3 is hydrogen, alkyl of 1 to 4 carbon atoms or acyl; R4 is alkyl of up to 4 carbon atoms, alkenyl of up to 4 carbon atoms or alkynyl of up to 4 carbon atoms; and R5, r6 and R7 are hydrogen, halogen or alkyl of 1 to 4 carbon atoms Are valuable pesticides, particularly insecticides.
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