- Continuous preparation method of 3, 4-dihydroxy-2, 5-hexanedione
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The invention discloses a continuous preparation method of 3, 4-dihydroxy-2, 5-hexanedione. The continuous preparation method comprises the following steps: conveying a reaction raw material into at least one fixed bed reactor which is filled with zinc powder and provided with a jacket through a metering pump, reacting, feeding a reaction liquid flowing out of the fixed bed reactor into a reactionliquid storage tank, and feeding into a subsequent extraction process. The invention discloses the method for continuously preparing 3, 4-dihydroxy-2, 5-hexanedione. An original intermittent kettle type reaction process can be replaced; compared with intermittent reaction technology, the method has advantages of high efficiency, stability, controllability and the like, the preparation efficiencyof 3, 4-dihydroxy-2, 5-hexanedione is more effectively improved by further utilizing a multi-fixed bed series connection technology, the controllability, safety and reaction conversion rate are better, side reactions are effectively inhibited, and the generation amount of three wastes is reduced.
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Paragraph 0023-0033
(2020/03/09)
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- Method for catalytically synthesizing 3, 4-dihydroxyl-2, 5-hexanedione by using organic amine salt
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The invention relates to a method for catalytically synthesizing 3, 4-dihydroxyl-2, 5-hexanedione by using an organic amine salt, a reaction formula is as shown in the specification, the reaction operation is simple and convenient, the reaction conditions are mild, the yield is higher, the cost is low, and the method is not only suitable for small-batch preparation in laboratories, but also suitable for industrial production. According to the invention, water is used as a reaction solvent, the post-treatment is simple, the pollution is small, and the corresponding organic amine salt water phase can be recycled after simple treatment.
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Paragraph 0026-0033
(2019/12/08)
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- A 3, 4 - dihydroxy - 2, 5 - hexanedione preparation method (by machine translation)
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The invention relates to a 3, 4 - dihydroxy - 2, 5 - hexanedione preparation method, characterized in that 1. With 5% -50% acetate solution; 2. Catalyst adds at different times, 5% -40% aldehyde solution, 10% -90% dilute sulfuric acid, acetate solution: catalyst: aldehyde solution: dilute sulfuric acid and the mass ratio of 10 - 300: 0.01 - 300:100: 30 - 300, feeding temperature - 20 - 60 °C, 10 - 80 °C insulation 1 - 24 of H; 3. Ethyl acetate extraction 4 - 20 times, 0.05 - 0.099 mpa distillation 10 - 600 minutes, add ethyl acetate, concentrate with ethyl acetate mass ratio is 1: 0.1 - 5, - 40 - 0 °C crystalline 4 - 72 of H, filtered. The advantage of this invention: 1. The method is simple, stable reaction, little side reaction, easy industrial amplifying; 2. The acidity of the reaction solution to overcome the large, zinc powder with an acid reaction is violent, production of a dangerous problem. (by machine translation)
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Paragraph 0018-0028
(2019/07/01)
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- Preparation method of furanone
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The invention discloses a preparation method of furanone. The preparation method includes the steps that an acetone aldehyde solution is prepared, a 3,4-dihydroxy-2,5-hexanedione solution is prepared,3,4-dihydroxy-2,5-hexanedione is purified, semi-finished furanone is prepared, and finished furanone is prepared. The preparation method has the advantages that 1, the yield of the intermediate 3,4-dihydroxy-2,5-hexanedione and the total yield of the furanone can be increased through composite catalyst zinc powder, iron powder and manganese powder, 2, purity of the intermediate 3,4-dihydroxy-2,5-hexanedione is obviously increased by adding anhydrous sodium sulphate and sodium chloride composite powder, and 3, purity of the furanone can be obviously improved by combining extractant ethanol andethyl acetate.
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Paragraph 0017-0019; 0032-0038
(2019/11/12)
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- A PROCESS FOR THE PREPARATION OF 1,4-DIALKYL-2,3-DIOL-1,4-BUTANEDIONE
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The present invention relates to a process for the preparation of compounds of a l,4-dialkyl-2,3-diol-l,4-butanedione by a acidic aldol condensation between an alkyl glyoxal and an α-hydroxy ketone.
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Page/Page column 5-6
(2009/01/20)
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- A NEW PROCESS FOR THE DIMERISATION OF ALKYL GLYOXALS
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The present invention relates to the field of organic synthesis and more particularly to a new process for the dimerisation of alkyl glyoxals, said process being promoted by an alkaline salt of the hydoxymethanesulfinic acid and is performed at a pH comprised between 3.5 and 9.5.
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Page/Page column 4; 5
(2008/06/13)
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- A PROCESS FOR THE PREPARATION OF 1,4-DIALKYL-2,3-DIOL-1,4-BUTANEDIONE
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The present invention relates to a process for the preparation of compounds of a 1,4-dialkyl-2,3-diol-1,4-butanedione by a catalytic aldol condensation between an alkyl glyoxal and an a-hydroxy ketone.
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Page/Page column 4; 5
(2008/06/13)
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