Separation system for 1, 4-butanediol and 2-alkyl-1, 4-butanediol

Abstract

The utility model discloses a separation system for 1, 4-butanediol and 2-alkyl-1, 4-butanediol, and relates to a separation system for 1, 4-butanediol and 2-alkyl-1, 4-butanediol. The separation system is provided with the desalting tower and the film evaporator, color-producing impurities such as hydroxybutyraldehyde, acetal, 2-(4-hydroxybutoxy) tetrahydrofuran and the like in raw materials of 1, 4-butanediol and 2-alkyl-1, 4-butanediol are converted into components easy to separate, and the proportion of a target product to be separated is effectively increased. Further, the 1, 4-butanediol and the 2-alkyl-1, 4-butanediol are separated through a first separation tower and a second separation tower, and the 1, 4-butanediol and the 2-alkyl-1, 4-butanediol are obtained.

Description

Technical Field

[0001] The utility model belongs to the chemical industry field, and particularly relates to a separation system for 1,4-butanediol (BDO) and 2-alkyl-1,4-butanediol. Background Art

[0002] 1,4-Butanediol (BDO) is commonly used in the production of tetrahydrofuran (THF), polytetrahydrofuran (PTMEG), γ-butyrolactone (GBL), N-pyrrolidone, etc., and is also commonly used in the synthesis of biodegradable materials such as polyesters like PBS, PBAT, PBT, etc.

[0003] 2-alkyl-1,4-butanediol, especially 2-methyl-1,4-butanediol (MBDO), is a kind of useful compound. Compared with BDO, it has a side chain added, so it also has some other characteristics. For example, some of the PBS, PBAT and other polymeric materials synthesized with alkyl-1,4-butanediol have more excellent low-temperature resistance and ductility. In addition, MBDO can be cyclized to the corresponding 3-alkyltetrahydrofuran, that is, 3-methyltetrahydrofuran. 3-methyltetrahydrofuran can be used as a raw material in the pharmaceutical industry, and can also be polymerized with other monomers and used as a prepolymer in industries such as chemical fiber, TPU, and sizing, greatly improving the low-temperature performance and human affinity of elastomers.

[0004] Currently, MBDO mainly comes from the by-products of BDO production devices. In the prior art, it is difficult to separate MBDO from BDO. On the one hand, the purity of BDO is affected, and on the other hand, there is no pure 2-alkyl-1,4-butanediol, resulting in its excellent properties not being applied. There have been patent literatures reporting that BDO and MBDO are kept mixed and further cyclized to obtain a mixture of tetrahydrofuran and 3-alkyltetrahydrofuran, which can then be used for polymerization to obtain special PTMEG. However, since the ratio of the two cannot be adjusted, the application of 2-alkyl-1,4-butanediol is limited.

[0005] In view of this, there is an urgent need to develop a system for separating 1,4-butanediol and 2-alkyl-1,4-butanediol (especially 2-methyl-1,4-butanediol). Summary of the Utility Model

[0006] In order to improve the above technical problems, the utility model provides a separation system for 1,4-butanediol and 2-alkyl-1,4-butanediol, including: a desalting tower and a thin-film evaporator;

[0007] The desalting tower is provided with a raw material inlet, an alkaline solution inlet, and a salt and heavy component outlet; the raw material is a raw material containing 1,4-butanediol and 2-alkyl-1,4-butanediol produced by the maleic anhydride method or the alkyne aldehyde method;

[0008] The thin-film evaporator is provided with a material inlet and a gas-phase outlet. The material inlet of the thin-film evaporator is connected to the salt and heavy-component outlet, and the gas-phase outlet of the thin-film evaporator is connected to the bottom of the desalting tower.

[0009] According to an embodiment of the present invention, the raw material inlet and / or the alkaline solution inlet are provided at the upper part of the desalting tower.

[0010] According to an embodiment of the present invention, the raw material further contains chromogenic impurities, such as acetal impurities, exemplified by hydroxybutyraldehyde and / or 2-(4-hydroxybutoxy)tetrahydrofuran (TBA), etc.

[0011] According to an embodiment of the present invention, the salt and heavy-component outlet is provided at the bottom of the desalting tower.

[0012] According to an embodiment of the present invention, the thin-film evaporator is further provided with a liquid-phase outlet at the bottom of the tower for extracting salts and heavy components.

[0013] According to an embodiment of the present invention, the gas-phase outlet of the thin-film evaporator is provided at the top of the thin-film evaporator.

[0014] According to an embodiment of the present invention, the material inlet of the thin-film evaporator is provided at the upper part of the thin-film evaporator.

[0015] According to an embodiment of the present invention, the desalting tower is provided with a light-component (rich in BDO, 2-alkyl-1,4-butanediol (such as MBDO), water, butanol, etc.) outlet at the top of the tower.

[0016] According to an embodiment of the present invention, the separation system further includes a light-component removal tower provided with a material inlet; further, the light-component outlet of the desalting tower is connected to the material inlet of the light-component removal tower.

[0017] According to an embodiment of the present invention, the light-component removal tower is further provided with a light-component outlet at the top of the tower for extracting light-component outlet impurities.

[0018] According to an embodiment of the present invention, the light-component removal tower is further provided with a liquid-phase outlet at the bottom of the tower for extracting a stream rich in BDO, 2-alkyl-1,4-butanediol (such as MBDO), and a small amount of heavy components.

[0019] According to an embodiment of the present invention, the separation system further includes a first separation tower provided with a material inlet; further, the material inlet of the first separation tower is connected to the liquid-phase outlet of the light-component removal tower.

[0020] According to an embodiment of the present invention, the first separation tower is further provided with a light-component outlet at the top of the tower for extracting BDO.

[0021] According to the embodiments of the present utility model, the first separation tower is further provided with a liquid phase outlet at the bottom of the tower to extract a stream rich in 2-alkyl-1,4-butanediol (such as MBDO) and a small amount of heavy components.

[0022] According to the embodiments of the present utility model, the separation system further includes a second separation tower, and the second separation tower is provided with a material inlet; further, the material inlet of the second separation tower is connected to the liquid phase outlet of the first separation tower.

[0023] According to the embodiments of the present utility model, the second separation tower is further provided with a light component outlet at the top of the tower for extracting 2-alkyl-1,4-butanediol, such as extracting MBDO.

[0024] According to the embodiments of the present utility model, the second separation tower is further provided with a liquid phase outlet at the bottom of the tower to extract a stream rich in 2-alkyl-1,4-butanediol (such as MBDO) and a small amount of heavy components. Further, the liquid phase outlet of the second separation tower is connected to the bottom of the desalting tower.

[0025] According to the embodiments of the present utility model, the desalting tower, the light component removal tower, the first separation tower, and / or the second separation tower is a distillation tower, preferably a plate distillation tower.

[0026] According to the preferred embodiments of the present utility model, the separation system includes:

[0027] A desalting tower, a thin-film evaporator, a light component removal tower, a first separation tower, and a second separation tower;

[0028] The desalting tower is provided with a raw material inlet containing 1,4-butanediol and 2-alkyl-1,4-butanediol, an alkaline solution inlet, a salt and heavy component outlet, and a light component outlet;

[0029] The thin-film evaporator is provided with a material inlet, a gas phase outlet, and a liquid phase outlet;

[0030] The light component removal tower, the first separation tower, and the second separation tower are all provided with a material inlet, a light component outlet, and a liquid phase outlet;

[0031] The material inlet of the thin-film evaporator is connected to the salt and heavy component outlet of the desalting tower, and the gas phase outlet of the thin-film evaporator is connected to the bottom of the desalting tower;

[0032] The light component outlet of the desalting tower is connected to the material inlet of the light component removal tower, the liquid phase outlet of the light component removal tower is connected to the material inlet of the first separation tower, the liquid phase outlet of the first separation tower is connected to the material inlet of the second separation tower, and the liquid phase outlet of the second separation tower is connected to the bottom of the desalting tower;

[0033] The light component outlet of the first separation column extracts BDO, and the light component outlet of the second separation column extracts 2-alkyl-1,4-butanediol (such as MBDO).

[0034] According to an embodiment of the present invention, the 2-alkyl-1,4-butanediol is 2-alkyl-substituted 1,4-butanediol, such as 2-C 1~20 alkyl, 2-C 1~10 alkyl or 2-C 1~4 alkyl (methyl, ethyl, propyl, isopropyl, butyl, isobutyl) substituted 1,4-butanediol, such as 2-methyl-1,4-butanediol.

[0035] Beneficial effects

[0036] The present invention provides a system for separating 1,4-butanediol and 2-alkyl-1,4-butanediol. By setting up a desalting column and a thin film evaporator, chromogenic impurities such as hydroxybutyraldehyde, acetal, and 2-(4-hydroxybutoxy)tetrahydrofuran in the raw materials of 1,4-butanediol and 2-alkyl-1,4-butanediol are converted into easily separable components, effectively increasing the proportion of the target products to be separated.

[0037] Furthermore, through the first separation column and the second separation column, 1,4-butanediol and 2-alkyl-1,4-butanediol are separated. Description of the drawings

[0038] Figure 1 is a schematic structural diagram of a separation system for 1,4-butanediol and 2-alkyl-1,4-butanediol;

[0039] The reference numerals are as follows:

[0040] V1 - thin film evaporator; T1 - desalting column; T2 - light removal column; T3 - first separation column; T4 - second separation column;

[0041] Logistics codes: 1 - raw material containing BDO and MBDO; 2 - light component logistics; 3 - salts and heavy components; 4 - gas-phase discharge; 5 - salts and heavy component tar; 6 - light component impurities; 7 - logistics rich in BDO, MBDO and a small amount of heavy components; 8 - BDO product; 9 - logistics rich in MBDO and a small amount of heavy components; 10 - MBDO product; 11 - logistics rich in MBDO and heavy components; 12 - alkaline aqueous solution. Detailed implementation manners

[0042] The technical solution of the present utility model will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative and explanatory purposes of the present utility model, and should not be construed as limiting the protection scope of the present utility model. All technologies implemented based on the above content of the present utility model are covered within the scope of protection intended by the present utility model.

[0043] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0044] Embodiment

[0045] As Figure 1 shown, the separation system of 1,4 - butanediol and 2 - alkyl - 1,4 - butanediol includes:

[0046] Desalting tower T1, thin - film evaporator V1, light - ends tower T2, first separation tower T3 and second separation tower T4;

[0047] The desalting tower T1 is provided with: a raw material inlet containing 1,4 - butanediol and 2 - alkyl - 1,4 - butanediol located in the middle of the tower, an alkaline solution inlet located in the upper part of the tower, a salt and heavy - component outlet located at the bottom of the tower kettle, and a light - component outlet located at the top of the tower;

[0048] The thin - film evaporator V1 is provided with: a material inlet located in the middle of the thin - film evaporator, a gas - phase outlet at the top and a liquid - phase outlet at the bottom;

[0049] The light - ends tower T2, the first separation tower T3 and the second separation tower T4 are all provided with a material inlet, a light - component outlet and a liquid - phase outlet;

[0050] The material inlet of the thin - film evaporator is connected to the salt and heavy - component outlet of the desalting tower, the gas - phase outlet of the thin - film evaporator is connected to the bottom of the desalting tower, and the liquid - phase outlet of the thin - film evaporator withdraws salt and heavy - components;

[0051] The light - component outlet of the desalting tower is connected to the material inlet of the light - ends tower, the light - component outlet of the light - ends tower withdraws light - component impurities, and the liquid - phase outlet of the light - ends tower is connected to the material inlet of the first separation tower;

[0052] The liquid - phase outlet of the first separation tower is connected to the material inlet of the second separation tower, and the light - component outlet of the first separation tower withdraws BDO products;

[0053] The liquid - phase outlet of the second separation tower is connected to the bottom of the desalting tower, and the light - component outlet of the second separation tower withdraws 2 - alkyl - 1,4 - butanediol (such as MBDO);

[0054] Preferably, the desalting tower, the light - ends tower, the first separation tower and the second separation tower are distillation towers, preferably plate - type distillation towers.

[0055] The specific working process is as follows: The raw material 1 containing BDO and MBDO produced by processes such as the maleic anhydride method or the acetylene aldehyde method, and further this raw material also contains acetal impurities such as hydroxybutyraldehyde and TBA, is fed into the desalting tower T1. The alkaline aqueous solution 12 containing sodium hydroxide or potassium hydroxide enters from the upper part of the desalting tower T1. The desalting tower T1 is preferably a plate column. In the desalting tower T1, impurities such as acetals are converted into easily separable components, namely salts and heavy components 3 under alkaline conditions. The salts and heavy components 3 enter the thin-film evaporator V1 from the bottom of the desalting tower T1. After further recovering BDO and MBDO in the thin-film evaporator V1, the salts and heavy component tar 5 are discharged from the bottom of the thin-film evaporator V1, and the gas-phase discharge 4 at the top enters the bottom of the desalting tower T1. The light-component stream 2 (the light-component stream is rich in BDO, MBDO, water, butanol, etc.) at the top of the desalting tower T1 is sent to the light-component removal tower T2, and the light-component impurities 6 (the light-component impurities are butanol, water, etc.) are removed from the top of the light-component removal tower T2. The stream 7 rich in BDO, MBDO and a small amount of heavy components is obtained at the bottom of the light-component removal tower T2. The stream 7 rich in BDO, MBDO and a small amount of heavy components is sent to the first separation tower T3, and the BDO product 8 is obtained at the top of the first separation tower T3. The stream 9 rich in MBDO and a small amount of heavy components at the bottom of the first separation tower T3 is sent to the second separation tower T4, and the MBDO product 10 is obtained at the top of the second separation tower T4. The stream 11 rich in MBDO and heavy components at the bottom of the second separation tower T4 is returned to the thin-film evaporator V1 to further recover useful components.

[0056] The system provided by the present utility model realizes the efficient separation of BDO, MBDO and impurities such as acetals, and obtains BDO and MBDO products.

[0057] The embodiments of the present utility model have been described above. However, the present utility model is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. Separation system for 1,4 - butanediol and 2 - alkyl - 1,4 - butanediol, characterized in that, The separation system includes: a desalting tower and a thin-film evaporator; The desalting tower is provided with a raw material inlet, an alkaline solution inlet, and a salt and heavy component outlet; the raw material is a raw material containing 1,4-butanediol and 2-alkyl-1,4-butanediol, the raw material inlet and / or the alkaline solution inlet is arranged at the upper part of the desalting tower, and the salt and heavy component outlet is arranged at the bottom of the desalting tower; The thin-film evaporator is provided with a material inlet and a gas-phase outlet, the material inlet of the thin-film evaporator is connected to the salt and heavy component outlet, and the gas-phase outlet of the thin-film evaporator is connected to the bottom of the desalting tower.

2. The separation system according to claim 1, characterized in that, The thin-film evaporator is further provided with a liquid-phase outlet at the bottom of the tower for extracting salt and heavy components; The gas-phase outlet of the thin-film evaporator is arranged at the top of the thin-film evaporator, and the material inlet of the thin-film evaporator is arranged at the upper part of the thin-film evaporator.

3. The separation system according to claim 1, wherein The desalting tower is provided with a light component outlet at the top of the tower.

4. The separation system according to claim 3, wherein, The separation system further includes a de-lighting tower provided with a material inlet; further, the light component outlet of the desalting tower is connected to the material inlet of the de-lighting tower.

5. The separation system according to claim 4, wherein The de-lighting tower is further provided with a light component outlet at the top of the tower for extracting impurities at the light component outlet; The de-lighting tower is further provided with a liquid-phase outlet at the bottom of the tower for extracting a logistics rich in BDO, 2-alkyl-1,4-butanediol and heavy components.

6. The separation system according to claim 5, characterized in that, The separation system further includes a first separation tower provided with a material inlet; further, the material inlet of the first separation tower is connected to the liquid-phase outlet of the de-lighting tower; The first separation tower is further provided with a light component outlet at the top of the tower for extracting BDO; The first separation tower is further provided with a liquid-phase outlet at the bottom of the tower for extracting a logistics rich in 2-alkyl-1,4-butanediol and heavy components.

7. The separation system according to claim 6, wherein The separation system further includes a second separation tower provided with a material inlet; further, the material inlet of the second separation tower is connected to the liquid-phase outlet of the first separation tower; The second separation tower is further provided with a light component outlet at the top of the tower for extracting 2-alkyl-1,4-butanediol; The second separation tower is further provided with a liquid-phase outlet at the bottom of the tower for extracting a logistics rich in 2-alkyl-1,4-butanediol and heavy components, and the liquid-phase outlet of the second separation tower is connected to the bottom of the desalting tower.

8. The separation system according to claim 7, wherein The desalting tower, the de-lighting tower, the first separation tower and / or the second separation tower is a rectification tower.

9. The separation system according to claim 8, wherein The desalting tower, the de-lighting tower, the first separation tower and / or the second separation tower is a plate rectification tower.

10. A separation system for 1,4 - butanediol and 2 - alkyl - 1,4 - butanediol, characterized in that, The separation system includes: a desalting tower, a thin-film evaporator, a de-lighting tower, a first separation tower and a second separation tower; The desalting tower is provided with a raw material inlet containing 1,4-butanediol and 2-alkyl-1,4-butanediol, an alkaline solution inlet, a salt and heavy component outlet, and a light component outlet; The thin-film evaporator is provided with a material inlet, a gas-phase outlet and a liquid-phase outlet; The de-lighting tower, the first separation tower and the second separation tower are all provided with a material inlet, a light component outlet and a liquid-phase outlet; The material inlet of the thin-film evaporator is connected to the salt and heavy component outlet of the desalting tower, and the gas-phase outlet of the thin-film evaporator is connected to the bottom of the desalting tower; The light component outlet of the desalting tower is connected to the material inlet of the light component removal tower. The liquid phase outlet of the light component removal tower is connected to the material inlet of the first separation tower. The liquid phase outlet of the first separation tower is connected to the material inlet of the second separation tower. The liquid phase outlet of the second separation tower is connected to the bottom of the desalting tower; BDO is withdrawn from the light component outlet of the first separation tower, and 2-alkyl-1,4-butanediol is withdrawn from the light component outlet of the second separation tower.

Images