1,3-butanediol synthesis method and system

A synthesis method and technology of butanediol, applied in chemical instruments and methods, preparation of heterocyclic compounds, preparation of hydroxyl compounds, etc., can solve the problems affecting product purity, odor, chroma, high viscosity of 3-hydroxybutyraldehyde, Color and taste indicators are unqualified and other problems, so as to improve the utilization rate of raw materials, reduce back-mixing, and improve stability.

Active Publication Date: 2018-08-10
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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Problems solved by technology

[0004] In the acetaldehyde condensation hydrogenation method currently used, the intermediate 3-hydroxybutyraldehyde is generally produced first. However, 3-hydroxybutyraldehyde has a high viscosity and is not stable. It will decompose when heated to about 85°C. In the production process, it is easy to be heated and dehydrated to produce toxic crotonaldehyde (crotonaldehyde). Crotonaldehyde contains both carbonyl and C=C double bonds. Under the same conditions of acetaldehyde condensation, crotonaldehyde can further condense with other aldehydes. Form complex polymers, while reducing the product yield of 1,3-butanediol, it greatly affects the purity, odor, color and other indicators of the product
Due to the strong condensation heat release, the reactants will quickly turn yellow, resulting in unqualified products
Moreover, the existing technology does not consider the impact of back-mixing, and the crotonaldehyde produced in the reaction system will flow back into the reaction system to continue to condense with other aldehydes, resulting in many by-products and unqualified color and taste indicators.
In addition, in the current production process, due to the influence of complex factors such as improper handling of raw materials, escape of acetaldehyde, low recovery rate of acetaldehyde, many by-products, and hydrogenation of acetaldehyde by subsequent processes, the final yield of 1,3-butanediol The yield is relatively low, the actual yield is usually below 75%, and the deodorization effect in the ordinary process is not ideal.

Method used

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  • 1,3-butanediol synthesis method and system

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preparation example Construction

[0041] A kind of synthetic method of 1,3-butanediol (1,3-BDO) provided by one aspect of the embodiment of the present invention, it comprises:

[0042] The condensation reaction system containing uniformly mixed acetaldehyde and alkali catalyst is carried out at 0-20°C for 11min-24h under the condition of pH value of 9-12.8, and the obtained product mainly contains 2,6-dimethyl- Condensation products of 1,3-dioxan-4-ol;

[0043] The cleavage reaction system comprising the 2,6-dimethyl-1,3-dioxan-4-ol and the cleavage catalyst is subjected to a cleavage reaction at 50-110°C for 1min-5h to obtain a Cleavage products of polybutyraldehyde;

[0044]Under the condition that the hydrogenation pressure is 1-15 MPa, the hydrogenation reaction system containing the dimer butanol aldehyde and the hydrogenation catalyst is subjected to ring-opening hydrogenation reaction at 60-180° C. for 0.2-20 hours to obtain 1, 3-butanediol.

[0045] Further, the condensation reaction is carried out...

Embodiment 1

[0096] Example 1 see figure 1 As shown, this embodiment is a specific implementation example of a process flow system for producing 1,3-butanediol from acetaldehyde.

[0097] Specifically, the process can include:

[0098] The aqueous solution containing 85% acetaldehyde and the alkali catalyst are mixed into the shell-and-tube condensation reactor with a built-in spiral member for reaction. The acid content in the raw material acetaldehyde is controlled below 0.05wt%, and the alkali catalyst used is NaOH, NaOH 2 CO 3 、Na 3 PO 4 The pH value of the reaction system was 10.1, the reaction time was 10 h, and the reaction temperature was controlled at 10°C. The outside of the tubular reactor is a circulating water cooling bath, which is counter-currently cooled, that is, the flow direction of the reactants inside the tube is opposite to the flow direction of the cooling water, and 2,6-dimethyl-1,3-dioxane is obtained after the reaction Hexan-4-ol-based product. The condensa...

Embodiment 2

[0102] The aqueous solution containing 83% acetaldehyde and the alkali catalyst are mixed into the tubular condensation reactor with a built-in spiral member for reaction. The acid content in the raw material acetaldehyde is controlled below 0.05 wt%, and the whole reaction process is carried out under nitrogen protection. The base catalyst used is NaOH, Na 3 PO 4 The mixed solution, the pH value of the reaction system is 10.0, the reaction time is 8h, and the reaction temperature is controlled at 0°C. The outside of the tube-and-tube reactor is a circulating water cooling bath, which is counter-currently cooled, that is, the flow direction of the reactants inside the tube is opposite to the flow direction of the cooling water. After the reaction, 2,6-dimethyl-1,3-dioxa Cyclohexane-4-ol-based product. The condensation product enters the neutralization tank, and the pH value of the reaction solution is neutralized to 6.2 with 5 wt % phosphoric acid aqueous solution under rap...

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Abstract

The invention discloses a 1,3-butanediol synthesis method and system. For the synthesis method, 1,3-butanediol is produced from acetaldehyde by a 2,6-dimethyl-1,3-dioxane-4-alcohol route; the stability of the intermediate product is improved; the selectivity of the 1,3-butanediol is improved; the generation of harmful, easy-color-developing and smelly crotonaldehyde and derivatives is reduced. Meanwhile, a tubular reactor with a built-in component is used as a condensation reactor; the heat can be effectively removed; the low-temperature cooling load is reduced; the reaction controllability isimproved; the unnecessary backmixing is reduced; the generation of by-products is reduced. The 2,6-dimethyl-1,3-dioxane-4-alcohol pyrolysis is performed in a mode of firstly performing low-temperature flash evaporation and then performing catalytic reaction distillation; the acetaldehyde is recovered; the raw material utilization rate is effectively improved; the yield of the final product is improved; the chromaticity and the odor can meet the requirements of most high-level application.

Description

technical field [0001] The invention relates to a method for synthesizing 1,3-butanediol (1,3-BDO), in particular to a method for synthesizing 1,3-butanediol and a used system, and belongs to the technical field of chemical industry. Background technique [0002] 1,3-Butanediol is an important fine chemical as a diol, which can be used as a raw material for polyester resins, alkyd resins, and polyurethanes, and can also be used as an excellent plasticizer. The toxicity of 1,3-butanediol to advanced animals is lower than that of 1,4-butanediol, which is about the same as that of glycerin, and has good moisturizing, antibacterial and antibacterial effects, and can be used in various advanced cosmetics , ointments, surfactants, hygroscopic formulations. [0003] The commonly used industrial production routes of 1,3-butanediol are: (1) Hydrogenation of acetaldehyde after condensation under alkali-catalyzed conditions; (2) Biological fermentation method; (3) Carbonylation of pro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/141C07C29/76C07C31/20C07C45/60C07C45/82C07C47/19C07D319/06
CPCC07C29/141C07C29/76C07C45/60C07C45/82C07D319/06C07C31/207C07C47/19
Inventor 夏春谷朱刚利王丹郧栋许传芝
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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