Method for treating waste liquid in 3-methyl-3-buten-1-ol production

Abstract

The present application provides a kind of 3-methyl-3-butene-1-al production waste liquid method, comprising (1) the waste liquid is enriched to obtain light component material by separating process 3-methyl-2-en-1,5-pentanediol and its isomer DIOL;(2) the light component material obtained in (1) is subjected to hydrogenation treatment, wherein the target product 3-methyl-1,5-pentanediol MPD crude product is obtained after the hydrogenation of DIOL;(3) the crude product after hydrogenation is refined to obtain MPD.3-methyl-3-butene-1-al process waste liquid 3-methylene-1,5-pentanediol and its isomer can be recycled, and the treated wastewater can be treated at low cost by using the existing wastewater treatment facilities in the park.

Description

Technical Field

[0001] This invention relates to the field of waste treatment technology, specifically to a method for treating waste liquid in the production of 3-methyl-3-buten-1-ol, and also includes a method for treating wastewater. Background Technology

[0002] 3-Methyl-3-buten-1-ol is the initiator for synthesizing TPEG polyether, a side chain of third-generation polycarboxylate superplasticizers for concrete. The TPEG polyether synthesized from this raw material plays a decisive role in the quality and performance of polycarboxylate superplasticizer products, giving them advantages such as strong cement particle dispersion retention, low dosage, high water reduction rate, good reinforcement effect, durability, non-corrosiveness to steel reinforcement, and environmental friendliness. Furthermore, 3-methyl-3-buten-1-ol can be isomerized to isopentenol, a key raw material for synthesizing methyl(ethyl) benzoate, a precursor to the biomimetic pesticide pyrethroids. It is also a key raw material for the artificial synthesis of citral, from which L-menthol and its derivatives, ionone fragrances, carotenoids and vitamin A fragrances, and nutrients can be further synthesized.

[0003] Numerous process schemes for synthesizing 3-methyl-3-buten-1-ol have been reported both domestically and internationally. The earliest disclosed method is the US patent US2335027A, which describes the thermal addition synthesis of 3-methyl-3-buten-1-ol from formaldehyde and isobutylene.

[0004] British patent GB1205397 reported the preparation of 3-methyl-3-buten-1-ol from isobutylene and gaseous paraformaldehyde at low temperature (20-80℃) under tin tetrachloride catalysis, but the reaction had problems with low conversion rate, selectivity and product yield.

[0005] US patent publication US4028424 and others report the preparation of the target product from isobutylene and paraformaldehyde at 250°C and 240 atmospheres using sodium monohydrogen phosphate and sodium dihydrogen phosphate as catalysts in tert-butanol or methanol solvent. The high temperature and high pressure reaction requires large equipment investment and complex process operation.

[0006] In summary, the current implementation plan for 3-methyl-3-buten-1-ol mainly involves the Prins reaction of isobutylene and formaldehyde in the presence of a catalyst. This reaction requires harsh conditions such as high temperature of 200-250℃ and high pressure of over 20MPa. The overall reaction yield is low, and a large amount of organic waste liquid and high-salt wastewater are generated, resulting in high treatment costs and greatly increasing the cost of equipment and the environmental pressure on enterprises.

[0007] Although there are very few public reports that mention treatment solutions for the organic waste liquid and high-salinity wastewater generated by this process, the chemical industry has mature treatment methods for these three wastes. Organic waste liquid is generally treated by direct incineration, while high-salinity wastewater is generally treated by concentration and crystallization to extract salt.

[0008] However, we should note that the organic waste liquid from this process contains a considerable amount of unsaturated diols, namely 3-methyl-2-ene-1,5-pentanediol and its isomers (hereinafter referred to as DIOL), with the following structural formula:

[0009] US Patent 4079088 discloses a process for preparing ISPO using DIOL. The process involves mixing isobutylene and DIOL at a temperature of 200°C to 450°C to prepare ISPO (3-methyl-3-buten-1-ol). However, the yield is low, ranging from only 10% to 32%, which limits the industrial application of this technology.

[0010] In contrast, directly hydrogenating DIOL after recycling to obtain 3-methyl-1,5-pentanediol (hereinafter referred to as MPD) would be a better choice. In particular, considering that the methyl branches in the structure of 3-methyl-1,5-pentanediol (MPD) give it many unique properties such as non-crystalline and hydrophobicity, it can be used to prepare polyester resins and alkyd resins for coatings with special properties, giving polyurethanes excellent flexibility, high transparency and compatibility.

[0011] At the same time, it should be noted that treating the wastewater from this process using a concentration and crystallization salt extraction method carries significant risks. Specifically, the wastewater contains a large amount of heavy components that are highly compatible with water, making it difficult to achieve the required purity for the byproduct salt obtained from evaporation and crystallization, or requiring a very low price to process. In short, the above treatment method is highly uneconomical for commercially operated facilities.

[0012] In summary, there is a need to develop a waste liquid and wastewater treatment process for the production of 3-methyl-3-buten-1-ol. Summary of the Invention

[0013] To solve the above-mentioned technical problems, the present invention provides a method for treating waste liquid in the production of 3-methyl-3-buten-1-ol, which can realize the recovery of 3-methylene-1,5-pentanediol and its isomers from the waste liquid of 3-methyl-3-buten-1-ol process.

[0014] The present invention also provides a method for treating wastewater in the production of 3-methyl-3-buten-1-ol, wherein the treated wastewater can be treated at low cost using existing wastewater treatment facilities in the industrial park.

[0015] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0016] A method for treating waste liquid produced during the production of 3-methyl-3-buten-1-ol includes the following steps:

[0017] (1) The waste liquid generated during the purification and separation of 3-methyl-3-buten-1-ol product is separated to enrich 3-methyl-2-en-1,5-pentanediol and its isomer DIOL to obtain light component materials.

[0018] (2) The light component material obtained in (1) is subjected to hydrogenation treatment, wherein 3-methyl-2-ene-1,5-pentanediol and its isomer DIOL are hydrogenated to obtain crude product MPD crude product containing 3-methyl-1,5-pentanediol.

[0019] (3) The crude product after hydrogenation was purified to obtain 3-methyl-1,5-pentanediol MPD;

[0020] Optionally, the following steps may also be included:

[0021] Step (4) The wastewater generated during the purification and separation of 3-methyl-3-buten-1-ol product is evaporated and concentrated to obtain concentrated wastewater;

[0022] (5) The concentrated wastewater is extracted using an extractant. The resulting oil phase contains DIOL and is returned to the 3-methyl-3-buten-1-ol unit for recycling and reprocessing.

[0023] (6) The water obtained by extraction and evaporation concentration is mixed and then fed into Fenton and / or CWAO and / or biochemical water treatment systems for treatment.

[0024] The waste liquid described in this invention is generated during the purification and separation process of 3-methyl-3-buten-1-ol product, and contains 1-5 wt% water, 1-10 wt% light component impurities (including but not limited to n-butanol, isoamyl alcohol, isopropanol, n-propanol and other low-carbon chain alcohols), 20-30 wt% ISPO, 30-40 wt% DIOL, and 20-40 wt% heavy component impurities.

[0025] The wastewater described in this invention contains 1-10% organic salts (including but not limited to sodium formate, potassium formate, sodium acetate, potassium acetate, etc.), 0.5-2 wt% DIOL, 1-5% polymers with a molecular weight of 300 or higher, and the remainder is water.

[0026] Considering the high boiling point of DIOL, the separation process described in this invention needs to be carried out under high vacuum conditions, preferably at 500-2000 PaA and 100-180°C. The equipment used is conventional separation equipment in the chemical industry, including but not limited to flash tanks, distillation kettles, thin-film evaporators, screw devolatilizers, horizontal self-cleaning devolatilizers, etc., with thin-film evaporators being preferred.

[0027] The hydrogenation treatment described in this invention can use known catalysts used in the hydrogenation of carbon-carbon double bonds, such as nickel, Raney nickel, palladium, Raney cobalt, platinum, ruthenium, etc. From the viewpoint of ease of handling and economy, Raney nickel is particularly preferred among these hydrogenation catalysts. The amount of hydrogenation catalyst used is generally preferably in the range of 0.01 to 5% by mass relative to the total amount of reaction liquid in the reactor, more preferably in the range of 0.1 to 1% by mass. The reaction temperature is not particularly limited, but from the viewpoint of the activity, economy, and operability of the hydrogenation catalyst, it is generally preferably in the range of 40 to 200°C, more preferably in the range of 50 to 120°C. The reaction pressure is not particularly limited, but from the viewpoint of operability, safety, reaction efficiency, and economy, it is generally preferably in the range of 0 to 10 MPa (gauge pressure), more preferably in the range of 1 to 5 MPa (gauge pressure). The reaction time is generally preferably in the range of 1 to 50 hours, more preferably in the range of 2 to 20 hours. Furthermore, this invention can be carried out under any conditions, with or without a solvent.

[0028] The refining process in step (3) of this invention employs a high-vacuum dual-tower distillation system. Considering that the hydrogenation products MPD and DIOL have very similar boiling points, in order to obtain qualified MPD products in the refining process, it is necessary to strictly control the DIOL content in the refining raw materials. The DIOL content in the refining raw materials is less than 0.5 wt%, more preferably less than 0.1 wt%. The light-light removal tower has 30-60 theoretical plates, an operating pressure of 5-15 hPaA, a reboiler temperature of 130-180°C, and a reflux ratio of 5-50. The product tower has 10-40 theoretical plates, an operating pressure of 5-20 hPaA, a reboiler temperature of 140-180°C, and a reflux ratio of 1-5.

[0029] The evaporation and concentration process described in step (4) of this invention can use known equipment and technology, including but not limited to distillation, scraped evaporation, single-effect or multi-effect evaporators and MVR, etc. Considering the composition characteristics of this wastewater and in order to reduce operating costs, MVR is preferred, wherein the evaporation and concentration ratio is controlled at 1 to 20 times, preferably 3 to 6 times.

[0030] The specific implementation scheme of the extraction process described in step (5) of this invention is not strictly limited, including but not limited to extraction tanks, continuous extraction machines, and rotary extraction towers. The extractant can be C4 or higher alcohols, including but not limited to n-butanol, n-octanol, isoamyl alcohol, isoisoamyl alcohol, and isopentenol. However, considering that no new impurities are introduced into the system and that adding separation equipment to remove new impurities would increase investment, ISPO is preferred as the extractant. The extraction feed mass ratio is ISPO:concentrated wastewater = 0.1–10:10, and the extraction temperature is 30–70°C. The extracted aqueous phase obtained after extraction, after mixing with the evaporated condensate, can be treated using Fenton and / or CWAO and / or biochemical methods within the industrial park.

[0031] Through the above-mentioned treatment process, 3-methylene-1,5-pentanediol and its isomers were recovered from the waste liquid of 3-methyl-3-buten-1-ol. In addition, the treated wastewater can be treated at low cost using the existing wastewater treatment facilities in the park, which greatly improves the profitability of the commercial operation unit.

[0032] Attached image description: Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0033] The following embodiments will further illustrate the method provided by the present invention, but the present invention is not limited to the listed embodiments and should also include any other known modifications within the scope of the claims of the present invention.

[0034] Waste liquid and wastewater: generated during the purification process of isopentenol reaction products prepared from formaldehyde and isobutylene.

[0035] Analysis method:

[0036] Gas chromatograph: Agilent 7890, column wax (conversion and selectivity determination), injection port temperature: 300℃; split ratio: 50:1; carrier gas flow rate: 52.8 ml / min; temperature program: hold at 150℃ for 10 min, increase to 260℃ at a rate of 10℃ / min, hold for 5 min, detector temperature: 280℃.

[0037] Example 1

[0038] The waste liquid contains: 3.4 wt% water, 6.2 wt% light component impurities, 21.6 wt% ISPO, 38.8 wt% DIOL, and the remainder is 30 wt% heavy component impurities.

[0039] The wastewater contains: 7.9% organic salts, 1.1 wt% DIOL, 2.6% polymers with a molecular weight of 300 or higher, and the remainder is water.

[0040] like Figure 1 As shown, the waste liquid is first treated by a thin-film evaporator to recover DIOL, with an operating pressure of 1500 PaA and an evaporation temperature of 150℃. The DIOL obtained by evaporation is then hydrogenated in a batch to obtain crude MPD, with a Raney catalyst addition of 1 wt%, an operating temperature of 120℃, an operating pressure of 4 MPaG, and a reaction time of 10 hours. The DIOL content in the crude MPD is 0.08 wt%. The crude MPD is then purified by a high-vacuum dual-tower distillation system. The light-light product removal tower has 40 theoretical plates, an operating pressure of 10 hPaA, a reboiler temperature of 160℃, and a reflux ratio of 20. The product tower has 20 theoretical plates, an operating pressure of 10 hPaA, a reboiler temperature of 150℃, and a reflux ratio of 2, yielding an MPD product with a purity of 99.5 wt% (product specification requirement > 98%).

[0041] Wastewater is evaporated and concentrated using MVR, resulting in concentrated wastewater after a 6-fold increase in concentration. The concentrated wastewater is then extracted using an extraction tank with ISPO as the extractant. The extraction feed mass ratio is ISPO:concentrated wastewater = 1:5, and the extraction temperature is 60℃. DIOL is enriched in the oil phase of the extraction and returned to the upstream separation process for recycling. The aqueous phase of the extraction is mixed with the evaporation condensate and then treated using the park's biochemical system.

[0042] Example 2

[0043] The waste liquid contains: 5 wt% water, 1.1 wt% light component impurities, and ISPO.

[0044] 29.8 wt%, DIOL 30.1 wt%, heavy component impurities 34 wt%.

[0045] The wastewater contains: 1.2% organic salts, 1.95 wt% DIOL, 4.98% polymers with a molecular weight of 300 or higher, and the remainder is water.

[0046] The waste liquid is first treated by a screw devourer to recover DIOL at an operating pressure of 500 PaA and an evaporation temperature of 100℃. The DIOL obtained by evaporation is then hydrogenated in a batch to obtain crude MPD with a Raney catalyst addition of 0.5 wt%, an operating temperature of 50℃, an operating pressure of 5 MPaG, and a reaction time of 20 hours. The DIOL content in the crude MPD is 0.02 wt%. The crude MPD is then purified by a high-vacuum dual-tower distillation system. The light-light distillation tower has 60 theoretical plates, an operating pressure of 5 hPaA, a reboiler temperature of 130℃, and a reflux ratio of 50. The product distillation tower has 10 theoretical plates, an operating pressure of 5 hPaA, a reboiler temperature of 140℃, and a reflux ratio of 1, to obtain MPD product with qualified purity.

[0047] Wastewater is evaporated and concentrated using MVR, resulting in concentrated wastewater after being concentrated three times. The concentrated wastewater is then extracted using an extraction tank with ISPO as the extractant. The extraction feed mass ratio is ISPO:concentrated wastewater = 0.1:10, and the extraction temperature is 70℃. DIOL is enriched in the extraction oil phase and returned to the upstream separation process for recycling. The extraction aqueous phase is mixed with the evaporated condensate and then treated using the park's biochemical system.

[0048] Example 3

[0049] The waste liquid contains: 1.1 wt% water, 10 wt% light component impurities, 26.7 wt% ISPO, 34.2 wt% DIOL, and 28 wt% heavy component impurities.

[0050] The wastewater contains: 10% organic salts, 0.5 wt% DIOL, 1% polymers with a molecular weight of 300 or higher, and the remainder is water.

[0051] The waste liquid is first treated in a distillation kettle to recover DIOL at an operating pressure of 2000 PaA and an evaporation temperature of 180℃. The DIOL obtained by evaporation is then hydrogenated in a kettle to obtain crude MPD with a Raney catalyst addition of 0.1 wt%, an operating temperature of 100℃, an operating pressure of 1 MPaG, and a reaction time of 2 hours. The DIOL content in the crude MPD is 0.1 wt%. The crude MPD is then purified using a high-vacuum dual-tower distillation system. The light-light product removal tower has 30 theoretical plates, an operating pressure of 15 hPaA, a reboiler temperature of 180℃, and a reflux ratio of 5. The product tower has 40 theoretical plates, an operating pressure of 20 hPaA, a reboiler temperature of 180℃, and a reflux ratio of 5, yielding MPD product with acceptable purity.

[0052] Wastewater is evaporated and concentrated using MVR, resulting in concentrated wastewater after being concentrated four times. The concentrated wastewater is then extracted using an extraction tank with ISPO as the extractant. The extraction feed mass ratio is ISPO:concentrated wastewater = 10:10, and the extraction temperature is 30℃. DIOL is enriched in the oil phase of the extraction and returned to the upstream separation process for recycling. The aqueous phase of the extraction is mixed with the evaporation condensate and then treated using the park's biochemical system.

Claims

1. A method for treating waste liquid in 3-methyl-3-buten-1-ol production, comprising the following steps: (1) The waste liquid is subjected to a separation process to enrich 3-methyl-2-ene-1, 5-pentanediol and its isomer DIOL to obtain a light component material; (2) The light component material obtained in (1) is subjected to hydrogenation treatment, wherein the DIOL is hydrogenated to obtain a target product 3-methyl-1, 5-pentanediol MPD crude product; (3) The crude product after hydrogenation is subjected to refining to obtain MPD; Further comprising the following steps: Step (4) Evaporating and concentrating the waste water generated in the refining and separation process of 3-methyl-3-buten-1-ol product to obtain concentrated waste water; (5) Extracting the concentrated waste water with an extractant, and returning the obtained extract oil phase containing DIOL to an upstream device for recycling; (6) Blending the extracted water phase and the evaporated water obtained by evaporation and concentration, and then feeding the blended water into a Fenton and / or CWAO and / or biochemical water treatment system for treatment.

2. The method of claim 1, wherein: The waste liquid is generated in the refining and separation process of 3-methyl-3-buten-1-ol product, and contains 1-5 wt% of water, 1-10 wt% of light component impurities, 20-30 wt% of 3-methyl-3-buten-1-ol ISPO, 30-40 wt% of DIOL, and 20-40 wt% of heavy component impurities.

3. The method of claim 1, wherein: The waste water contains 1-10% of organic salts, 0.5-2 wt% of DIOL, 1-5% of high polymers with a molecular weight of 300 or more, and the rest is water.

4. The method according to any one of claims 1-3, characterized by: The separation process in step (1) needs to be carried out under high vacuum conditions, and the equipment is conventional separation equipment in the chemical industry, including flash tank, distillation still, thin film evaporator, screw devolatilizer, and horizontal self-cleaning devolatilizer.

5. The method of claim 4, wherein: The separation process in step (1) is carried out at 500-2000 paA and 100-180℃, and the separation equipment adopts a thin film evaporator.

6. The method of any one of claims 1-3, wherein: The catalyst used in the hydrogenation treatment in step (2) includes one or more of nickel, Raney nickel, palladium, Raney cobalt, platinum, and ruthenium; and the amount of catalyst used is in the range of 0.01-5 mass% relative to the total amount of reaction liquid in the reactor.

7. The method of claim 6, wherein: The catalyst used in the hydrogenation treatment in step (2) is Raney nickel, and the amount of catalyst used is in the range of 0.1-1 mass% relative to the total amount of reaction liquid in the reactor.

8. The method of any one of claims 1-3, wherein: The reaction temperature for the hydrogenation treatment in step (2) is in the range of 40-200℃; and / or, the reaction pressure is in the range of 0-10 MPa of gauge pressure; and / or, the reaction time is in the range of 1-50 hours.

9. The method of claim 8, wherein: The reaction temperature for the hydrogenation treatment in step (2) is in the range of 50-120℃; and / or, the reaction pressure is in the range of 1-5 MPa of gauge pressure; and / or, the reaction time is in the range of 2-20 hours.

10. The method of any one of claims 1-3, wherein, The refining process in step (3) adopts a high vacuum double-column rectification system comprising a light component removal column and a product column, and the content of DIOL in the refined raw material is controlled to be less than 0.5%.

11. The method of claim 10, wherein, The content of DIOL in the refined raw material is controlled to be less than 0.1%.

12. The method of claim 10, wherein, The light-removing column has 30-60 theoretical plates, the operating pressure is 5-15 hpaA, the column bottom temperature is 130-180 DEG C, and the reflux ratio is 5-50; and / or, the product column has 10-40 theoretical plates, the operating pressure is 5-20 hpaA, the column bottom temperature is 140-180 DEG C, and the reflux ratio is 1-5.

13. The method of any one of claims 1-3, wherein: The evaporation concentration ratio in the evaporation concentration process in step (4) is controlled to be 1-20 times.

14. The method of claim 13, wherein: The evaporation concentration ratio in the evaporation concentration process in step (4) is controlled to be 3-6 times.

15. The method of any one of claims 1-3, wherein: The extractant used in the extraction process in step (5) is a C4 and above alcohol, and / or the extraction feed ratio is extractant: concentrated waste water = 0.1-10:10, and the extraction temperature is 30-70 DEG C.

16. The method of claim 15, wherein: The extractant used in the extraction process in step (5) is n-butanol, n-octanol, isoamyl alcohol, isoisoamylene alcohol, isoamylene alcohol.

17. The method of claim 16, wherein: The extractant used in the extraction process in step (5) is isoisoamylene alcohol.

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