- Preparation method of 4-halobutyl acetate
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The invention discloses a preparation method of 4-halobutyl acetate, relates to the preparation method of acetate and aims to solve the technical problems that in an existing method for preparing the4-halobutyl acetate, the reaction time is long, the reaction temperature is high, the cost is high, a toxic reagent is used, the operation is complicated, and the yield is low. The preparation methodcomprises the following steps: mixing and stirring urea, tetrahydrofuran and acetyl halide, naturally cooling to room temperature, adding distilled water, regulating pH (Potential of Hydrogen) to be neutral, carrying out suction filtration, extracting, drying, filtering, and distilling. The 4-halobutyl acetate prepared by the invention structurally contains an ester group and chain end halogen andis a multi-purpose polyfunctional compound. The 4-halobutyl acetate prepared by the invention is prepared from corresponding acyl halide and cyclic ether under catalysis of the urea, and the preparation method is bran-new. A solid byproduct of the preparation method is acyl urea. The preparation method disclosed by the invention has the advantages of simple operation, low cost, safety and high efficiency, environment friendliness and the like.
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Paragraph 0073-0080; 0087-0088; 0091
(2018/09/20)
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- Synthesis method of acetylurea crystal compound
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The invention provides a synthesis method of an acetylurea crystal compound. The synthesis method comprises synthesis, separation and purification; the synthesis comprises the following steps: under awater-free and oxygen-free condition, weighing 0.3370g of anhydrous zinc chloride, 1.6449g of 1-phenyl-1,3-butanedione and 1.9879g of urea and putting into a 100mL two-opening flask; adding 40mL of chlorobenzene and reflowing and stirring; after reacting for 48h, obtaining solid sediment; then adding dichloromethane, absolute ethyl alcohol and a DMF (Dimethyl Formamide) solvent and naturally volatilizing a solution to obtain a white transparent crystal. A chemical formula is as follows: the formula is shown in the description.
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Paragraph 0008
(2018/03/26)
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- Method for synthesis of high-concentration anhydrous peracetic acid solution and co-production of acetylurea
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The invention discloses a method for synthesis of a high-concentration anhydrous peracetic acid solution and co-production of acetylurea. According to the method, peracetic acid and acetylurea are generated via a reaction between percarbamide and acetic anhydride under the action of a catalyst; and then the high-concentration anhydrous peracetic acid solution is separated out via vacuum distillation, the residual distillate is frozen, and the frozen residual distillate is recrystallized for preparation of acetylurea, wherein the catalyst is selected from boric acid, metaboric acid, sodium borate, sodium metaborate, sodium perborate or a corresponding hydrate. As the raw materials, percarbamide and acetic anhydride are cheap and easy to obtain; compared with a method for preparing the anhydrous peracetic acid solution via acetaldehyde oxidation, the method provided by the invention is simpler, less in equipment investment and safer; and by adoption of the method provided by the invention, both the anhydrous peracetic acid solution and acetylurea are prepared, so that the application range is broad and the added value is high.
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Paragraph 0021; 0022
(2017/02/09)
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- Oxyhalogen-sulfur chemistry: Kinetics and mechanism of oxidation of N-acetylthiourea by aqueous bromate and acidified bromate
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The oxidation of N-acetylthiourea (ACTU) by acidic bromate has been studied by observing formation of bromine in excess bromate conditions. The reaction displays an induction period before formation of bromine. The stoichiometry of the reaction wasdeterminedtobe4:3:4BrO3-+3(CH3CO)NH(NH2)C=S+3H2O→4Br-+3(CH3CO)NH(NH2)C=O+3SO42-+6H+(A)witha complete desulfurization of ACTU to its urea analogue. In excess bromate conditions the stoichiometry was 8:5:8BrO3-+ 5(CH3CO)NH(NH2)C=S + H2O → 4Br2+ 5(CH3CO)NH(NH2)C=O + 5SO42-+ 2H+(B). Bromine is derived from an extraneous reactionin which bromide fromstoichiometry (A) reacts with excess acidic bromate. The oxidation of ACTU byaqueous bromine gavestoichiometry(C):4Br2(aq)+(CH3CO)NH(NH2)C=S+5H2O→8Br-+(CH3CO)NH(NH2)C=O+SO42-+10H+.Reaction(C) is much faster than reactions (A) and (B), with a lower limit bimolecular rate constant of 2.1 ×105M-1s-1such that appearance of bromine signals complete consumption of ACTU. We were unable to trap any intermediate sulfur oxo-acids of ACTU on its oxidation pathwayto N-acetylurea. As opposed toother substituted thioureas, none ofits intermediates werestable enough to be isolated and detected.
- Chipiso, Kudzanai,Mbiya, Wilbes,Tran, Thai,Simoyi, Reuben H.
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- Influence of N-donor bases and the solvent in oxodiperoxomolybdenum catalysed olefin epoxidation with hydrogen peroxide in ionic liquids
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Biphasic catalytic olefin epoxidation systems consisting of oxodiperoxomolybdenum catalysts in 1-n-alkyl-3-methylimidazolium hexafluorophosphate ionic liquid (IL) media with aqueous hydrogen peroxide oxidant were optimised by tuning the molecular structure of the IL and employing N-heterocyclic donor base additives to inhibit hydrolysis and enhance the activity of the catalyst. The latter study was only made possible by the solubilising properties of the IL media. Of the bases investigated, pyrazoles were identified as the most efficient additive species and the best results were obtained using 3,5-dimethylpyrazole. Immobilisation of the catalyst in the IL allowed for very efficient catalyst recycling. Finally, the compound [MoO(O 2)2(3-Mepz)2] (3-Mepz = 3-methylpyrazole) was characterised and its structure determined by X-ray crystallography.
- Herbert, Matthew,Montilla, Francisco,Galindo, Agustin,Moyano, Raquel,Pastor, Antonio,Alvarez, Eleuterio
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supporting information; scheme or table
p. 5210 - 5219
(2011/06/22)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Acyl iodides in organic synthesis. Reactions of acetyl iodide with urea, thiourea, and their N,N′-disubstituted derivatives
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Acetyl iodide reacted with urea and its derivatives to give the corresponding N-substituted products. The reactions of acetyl iodide with thiourea, N,N′-dimethylthiourea, imidazolidine-2-thione, and hexahydropyrimidine-2-thione resulted in the formation o
- Voronkov,Vlasova,Grigor'Eva,Belousova,Vlasov
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experimental part
p. 486 - 490
(2009/08/17)
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- Process for producing 5-perfluoroalkyluracil derivatives
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A novel process is provided for producing a 5-perfluoroalkyl-5,6-dihydrouracil represented by General Formula (1): (where R1 and R2 are independently hydrogen, methyl, or ethyl, and Rf is a perfluoroalkyl of 1 to 10 carbons). The process comprises reacting alpha -perfluoroalkylacrylic acid represented by General Formula (2): CH2=C(Rf)-COOH(2) with a urea derivative represented by General Formula (3): R1NHCONHR2(3) in the presence of acetic anhydride with formed acetic acid being removed out of the reaction system during the reaction. The alpha -perfluoroalkylacrylic acid may be added successively. A process for producing a 5-perfluoroalkyl-5-bromo-6-hydrouracil by General Formula (4) is also provided: (where R1, R2, and Rf are as defined above) wherein the reaction of a 5-perfluoroalkyl-5,6-dihydrouracil produced by the above process with bromine is conducted in water as the solvent. The process of the present invention can be industrially conducted safely and simply at a high yield.
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- A study on the stability of 5,5-diamino-substituted- 1,4,2- oxathiazoline derivatives
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5,5-Diamino-substituted-1,4,2-oxathiazoline derivatives 3 as potential prodrugs, which were easily prepared from hydroximoyl chlorides I and the appropriate thiourea derivatives 2, were decomposed instantaneously into isothiocyanates 4 and the corresponding urea derivatives 5 irrespective of the substituents.
- Jung, Keum Shin,Lee, Hong Jung,Song, Hyun Nam,Kim, Jae Nyoung
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p. 1879 - 1884
(2007/10/03)
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- Photo-oxidation of Oxazolidones and Hydantoins in the Presence of Benzophenone
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Irradiation in the presence of benzophenone and oxygen of nitrogen-containing heterocycles having an NCO group yields products arising out of regioselective oxidation α to the nitrogen atom.Direct irradiation (in the absence of benzophenone and oxygen) of 5-methyl- and 5,5-dimethyl-hydantoins yields allophanates.The first step of this reaction involves the homolysis of the C(4) - C(5) bond of the hydantoin.
- Gramain, Jean-Claude,Remuson, Roland
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p. 2341 - 2346
(2007/10/02)
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