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A diketone and condensation reaction technology, applied in the field of preparation of β-diketone, can solve the problems of yield reduction, change of raw material ratio, etc.
Active Publication Date: 2009-06-24
KUNSHAN CITY BANMING ELECTRONICS SCI & TECH
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[0013] The above method also has the following defects: in the process of raising the temperature, part of the ester and th...
Method used
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specific Embodiment approach 1
[0049] A kind of preparation method of β-diketone is as follows:
[0050] In a 1000ml four-diameter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser and a constant pressure dropping funnel, add 16g of sodium amide and 100ml of xylene. Turn on nitrogen, start stirring, and then heat to raise the temperature.
[0051] When the temperature increased to 135° C., start to drop the liquid pre-mixed homogeneously by 110 g of methyl octanoate, 30 g of acetophenone and 50 ml of xylene, and the time required for the dropwise addition process was about 1.5 hours.
[0052] At 140°C, heat preservation and condensation reaction for 5 hours, then stop the reaction.
[0053] The mother liquor was rapidly cooled to room temperature within 30 minutes. Then add crushed ice cubes to continue to drop the temperature of the mother liquor to below 0°C.
[0054] Under stirring, the mother liquor is neutralized to neutrality with sulfuric acid with a mass rati...
specific Embodiment approach 2
[0058] The preparation method of another kind of β-diketone is as follows:
[0059] In a 1000ml four-diameter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, a reflux condenser and a constant pressure dropping funnel, add 27g of methanol and 100ml of xylene. Nitrogen was turned on and stirring followed by an increase in temperature.
[0060] When the temperature increased to 135° C., start to drop the liquid pre-mixed homogeneously by 110 g of methyl caprate, 30 g of acetophenone and 50 ml of xylene, and the time required for the dropwise addition process was about 2.0 hours.
[0061] The subsequent process is the same as that in the first embodiment. The obtained β-diketone has a purity of 95% and a yield of 93%.
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Abstract
The invention relates to a preparation method of beta-diketone; Claisen condensation reaction is adopted; the chemical general expression of the beta-diketone is R1COCH2COR2, wherein, R1 is C6-C12 alkyl, and R2 is phenyl or alkylphenyl; the method comprises the following steps: ester, phenyl ketone and partial solvent are pre-mixed for spare; a condensating agent and remaining solvent are added in a reactor, and the temperature is raised under nitrogen atmosphere; during the period when the temperature of the reactor is raised to the needed temperature of the condensation reaction, the pre-mixed material is dropwise added in the reactor for carrying out the condensation reaction with a system which is composed of the condensating agent and the remaining solvent under an infinite reflux condition; after the pre-mixed material is dropwise added, heat-preserving condensation reaction is carried out continuously under the infinite reflux condition. The ester and the condensating agent in the raw material are contacted when the reacting condition is achieved, and acylation reaction is slow reaction, relative to the Claisen condensation reaction, thus being capable of better solving the acidylation problem of the ester, and reducing the effect of the acylation reaction to the minimum; the yield of the beta-diketone is more than or equal to 90 percent.
Description
technical field [0001] The present invention relates to condensed acyclic or carbocyclic compounds, in particular to a preparation method of β-diketone. Background technique [0002] The extraction performance of β-diketones showed that it is an effective copper extractant. When preparing β-diketone compounds, the Claisen condensation reaction is usually adopted, and the synthesis is carried out under the catalytic action of a condensing agent. For example, ester, inert hydrocarbon solvent and condensing agent are first added to the reactor, and the ketone or its derivatives are added dropwise during the period when the temperature is raised to the temperature required for the condensation reaction. Chinese invention patent CN1046498C announced a kind of "improved method for preparing β-diketone", which includes the following steps: [0003] (A) reacting acetophenone and an ester in the presence of a basic catalyst in an inert hydrocarbon solvent at the reflux temperature ...
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