Process method for preparing 2-ethyl-2-hexenal by catalyzing self-condensation of n-butanal with heteropoly acid

A process method and technology of heteropoly acid, applied in the field of green chemistry, can solve the problems of poor stability of solid base catalyst, difficult to reuse, and the cost of three-waste treatment that cannot be reused for liquid base catalyst, so as to achieve easy continuous production and overcome poor stability. , The effect of reusable continuous production

Inactive Publication Date: 2012-10-24
HEBEI UNIV OF TECH
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  • Abstract
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Problems solved by technology

[0010] The purpose of the present invention is to provide a method for the self-condensation of n-butyraldehyde to prepare 2-ethyl alcohol for the shortcomings of the current technology that the liquid alkali catalyst cannot be reused, the cost of three wastes is high, and the solid alkali catalyst is poor in stability and difficult to reuse. Heteropolyacid Catalysts for the Reaction of -2-Hexenal

Method used

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  • Process method for preparing 2-ethyl-2-hexenal by catalyzing self-condensation of n-butanal with heteropoly acid
  • Process method for preparing 2-ethyl-2-hexenal by catalyzing self-condensation of n-butanal with heteropoly acid
  • Process method for preparing 2-ethyl-2-hexenal by catalyzing self-condensation of n-butanal with heteropoly acid

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Embodiment 1

[0033] In a 100ml autoclave, put 30g of n-butyraldehyde, and then add 0.5% H of n-butyraldehyde weight 4 SiW 12 o 40 Catalyst, with N 2 Air replacement, magnetic stirring, and reaction at 100°C for 4 hours. After the reaction, filter under reduced pressure, and perform gas chromatography analysis on the product liquid. The conversion rate of n-butyraldehyde is 91.9%, and the conversion rate of 2-ethyl-2-hexenal The selectivity was 88.1%.

[0034] Examples 2-48 According to the operation steps of Example 1, the reaction conditions and results are shown in the summary table.

[0035]

[0036]

[0037]

Embodiment 49

[0039] 10wt%H prepared by sol-gel method 4 SiW 12 o 40 / SiO 2 For catalyst, in 100ml autoclave, put into 30g n-butyraldehyde, then add the H of n-butyraldehyde weight 5%. 4 SiW 12 o 40 / SiO 2 Catalyst, with N 2 Air replacement, magnetic stirring, and reaction at 120°C for 3 hours. After the reaction, filter under reduced pressure, and perform gas chromatography analysis on the filtrate. The conversion rate of n-butyraldehyde is 92.4%. The selection of 2-ethyl-2-hexenal Sex is 85.0%. The reacted H 4 SiW 12 o 40 / SiO 2 The catalyst was washed three times with absolute ethanol and dried at 60 °C for 4 h. Then under the same reaction conditions, the repeated use effect of the catalyst was investigated, and the results are shown in the table below. With the increase of the number of reactions, the activity of the catalyst decreased, and the selectivity of 2-ethyl-2-hexenal decreased by 5.2% after being used for 4 times, but the catalyst still had a high activity.

[0...

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Abstract

The invention provides a process method for preparing 2-ethyl-2-hexenal (octenal) by catalyzing self-condensation of n-butanal with heteropoly acid. The method comprises the following steps of: adding n-butanal and a heteropoly acid catalyst into a high-pressure kettle, wherein the using amount of the catalyst is 0.5-15 percent of the mass of the added n-butanal; reacting under a magnetic stirring action at the temperature of 20-150 DEG C for 0.5-8 hours; and performing a self-condensation reaction on the n-butanal to obtain 2-ethyl-2-hexenal. The heteropoly acid catalyst used in the method is a heteropoly acid (salt) or supported heteropoly acid (salt) catalyst, has high low-temperature activity and high selectivity, and can be used repeatedly. The transformation rate of the n-butanal can be up to 99.7 percent in maximum, the selectivity of the 2-ethyl-2-hexenal can be up to 88.1 percent in maximum, the catalytic activity of the heteropoly acid catalyst is approximate to that of the conventional industrial liquid alkali, and the method has a good industrial application prospect.

Description

technical field [0001] The invention relates to the technical field of green chemistry, in particular to a process for preparing 2-ethyl-2-hexenal by heteropolyacid-catalyzed self-condensation of n-butyraldehyde. Background technique [0002] The self-condensation of n-butyraldehyde to prepare 2-ethyl-2-hexenal (octenal) is a typical aldol condensation reaction, which can be carried out under the condition of acid or base catalyst. Due to the strong electronegativity of the oxygen atom, the carbonyl group has an electron-withdrawing inductive effect; in addition, the carbon-hydrogen bond on the α-carbon of the carbonyl group has a σ-π hyperconjugation effect with the carbonyl group. The combined effect of inductive effect and hyperconjugation effect makes the hydrogen on the α-carbon atom active, and the active α-hydrogen can move between the α-carbon and carbonyl oxygen. Therefore, carbonyl compounds exist in a pair of tautomers, ie, keto and enol, which exist together in ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/21C07C45/74
Inventor 赵新强陈翠娜安华良王延吉
Owner HEBEI UNIV OF TECH
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