A method for preparing functional chemicals from waste polyhydroxybutyrate
By using a Lewis base-alcohol composite catalyst to decompose waste PHB into high-purity butenoic acid at low temperature, the problem of high temperature and high energy consumption in the existing technology is solved, and efficient PHB recycling and high-purity butenoic acid preparation are realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2026-04-10
- Publication Date
- 2026-06-26
AI Technical Summary
Existing chemical recovery technologies for polyhydroxybutyrate (PHB) suffer from problems such as high reaction temperature, high energy consumption, low catalyst efficiency, and poor depolymerization selectivity, resulting in unsatisfactory yield and purity of butenoic acid, making it difficult to achieve stable industrial production.
A Lewis base-alcohol composite catalyst was prepared by heating and then reacted with waste polyhydroxybutyrate to obtain high-purity butenoic acid.
The preparation of butenoic acid with high yield (>99%) and high purity (>98%) was achieved at a relatively low temperature, which promoted the recycling of waste PHB, reduced side reactions and ecological burden, and is in line with the concept of circular economy.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of waste plastic degradation, specifically relating to a method for preparing functional chemicals from waste polyhydroxybutyrate. Background Technology
[0002] Polyhydroxybutyrate (PHB), a bio-based polyester synthesized by microorganisms, is considered an ideal alternative to petroleum-based plastic pollution due to its fully biodegradable nature. Under standard industrial composting conditions (such as high temperature, high humidity, and specific microbial communities), it can be completely decomposed into carbon dioxide and water, aligning with the principles of a circular economy. However, PHB's biodegradability has significant limitations. In natural environments (such as soil and water bodies) or conventional landfills, its slow decomposition rate, lacking ideal degradation conditions, may lead to white pollution and ecological burden.
[0003] Currently, the treatment and high-value recycling of waste PHB still face severe challenges. Traditional physical recycling (melting and regranulation) severely damages its mechanical properties and has low economic value. Efficient chemical recycling, especially depolymerization to generate its monomer butylene acid, is considered a key pathway to achieve a closed-loop cycle. Butylene acid is not only a raw material for synthesizing high-purity PHB, but it is also a high-value fine chemical. Existing chemical recycling technologies (such as high-temperature pyrolysis or thermocatalytic pyrolysis using tin-based or zinc-based catalysts) generally suffer from high reaction temperatures (>200℃), high energy consumption, low catalyst efficiency, and poor depolymerization selectivity, resulting in unsatisfactory butylene acid yield and purity, numerous side reactions, and difficulty in achieving continuous and stable industrial production. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for preparing functional chemicals from waste polyhydroxybutyrate, so as to solve the problems of high reaction temperature, high energy consumption, low catalyst efficiency and poor depolymerization selectivity in the existing polyhydroxybutyrate chemical recycling technology.
[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0006] A method for preparing functional chemicals from waste polyhydroxybutyrate includes the following steps: (1) A Lewis base-alcohol composite catalyst was prepared by mixing a Lewis base and a high-boiling-point alcohol and heating the mixture. (2) The Lewis base-alcohol composite catalyst obtained in step (1) is reacted with waste polyhydroxybutyrate to obtain butenoic acid.
[0007] In some embodiments, in step (1), the Lewis base is an organic base and / or an inorganic base.
[0008] In some embodiments, the organic base comprises a compound containing nitrogen, phosphorus, or oxygen and having lone pair electron donor capability; preferably, the organic base is any one of triethylamine, pyridine, 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, imidazole, 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphonobenzene, 1,5-diazabicyclo[4.3.0]non-5-ene, triphenylphosphine, alkali metal alkoxide, or alkali metal carboxylate; preferably, the alkali metal alkoxide is any one of potassium ethoxide, sodium isopropoxide, or sodium methoxide, and the alkali metal carboxylate is sodium acetate, sodium butenoate, or sodium stearate; the inorganic base is any one or more of alkali metal hydroxide, alkali metal carbonate, alkali metal phosphate, alkali metal borate, or alkaline earth metal hydroxide, preferably sodium hydroxide.
[0009] In some embodiments, in step (1), the high-boiling-point alcohol is selected from any one of straight-chain saturated fatty alcohols, straight-chain unsaturated fatty alcohols, branched fatty alcohols, modified fatty alcohols, or polyol polymers with 10 to 30 carbon atoms.
[0010] In some embodiments, the straight-chain saturated fatty alcohol is any one of decanol, lauryl alcohol, stearyl alcohol, or docosyl alcohol; the straight-chain unsaturated fatty alcohol is any one of palm oil alcohol or oleyl alcohol; the branched fatty alcohol is an isomer alcohol, preferably Guerbert alcohol or carbonyl synthetic alcohol; the modified fatty alcohol is an ethoxylated alcohol; the polyol polymer is a polyether polyol with a molecular weight of 500 Da to 1500 Da, preferably, the polyether polyol is any one of polyethylene glycol or polypropylene glycol.
[0011] In some embodiments, in step (1), the molar ratio of the Lewis base to the high-boiling alcohol is 1:1 to 30.
[0012] In some embodiments, in step (1), the heating reaction is carried out at a temperature of 140~300℃ for a time of 0.5~3h.
[0013] In some embodiments, in step (2), the weight-average molecular weight of the waste polyhydroxybutyrate is 10 kDa to 600 kDa.
[0014] In some embodiments, in step (2), the mass ratio of the Lewis base-alcohol composite catalyst to waste polyhydroxybutyrate is 1:100~3000.
[0015] In some embodiments, in step (2), the reaction is carried out at a temperature of 100~160°C, a pressure of 0.5~10 torr, and a time of 0.5~3h.
[0016] Beneficial effects:
[0017] (1) The Lewis base-alcohol composite catalyst prepared by the present invention can decompose waste PHB into high-purity functional chemical butenoic acid at a lower temperature, and has a high yield (>99%) and purity (>98%).
[0018] (2) The method of the present invention effectively promotes the recycling of waste PHB, with few side reactions and high selectivity for products, which can reduce white pollution and ecological burden, and is in line with the concept of circular economy and sustainable development. Attached Figure Description
[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.
[0020] Figure 1 This is a graph showing the gas phase characterization results of the product butenoic acid in Example 1;
[0021] Figure 2 The image shows the FTIR spectrum of the Lewis base-alcohol composite catalyst prepared in Example 1. Detailed Implementation
[0022] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.
[0023] This invention employs gas chromatography for the qualitative and quantitative analysis of butenoic acid products. The chromatographic conditions are as follows: a non-polar capillary column (e.g., HP-5), programmed temperature ramp, injection port temperature 250°C, and detector (FID) temperature 300°C. Qualitative analysis is performed using retention time (compared to standards), and quantification is achieved using area normalization. Linearity and recovery are verified using external standard method to ensure accuracy. The sample is directly injected after dilution, allowing for rapid separation of solvent, target product, and byproduct impurities.
[0024] Example 1
[0025] (1) Sodium butenoate and stearyl alcohol were mixed at a molar ratio of 1:20 and heated at 190°C for 1 hour. Byproducts were removed by vacuum distillation to obtain Lewis base-alcohol composite catalyst.
[0026] (2) Add 20 g of PHB with a weight-average molecular weight of 480 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:100, and the reaction is carried out at 150℃ and a vacuum of 2 torr for 3 hours. Collect the distillation product to obtain butenoic acid. The yield of butenoic acid was 98.2% and the purity was 99.6% by gas chromatography. Figure 1 ).
[0027] The Lewis base-alcohol composite catalyst prepared in Example 1 was analyzed by FTIR, and the results are as follows: Figure 2 As shown.
[0028] Figure 2 (a) Stearyl alcohol and stearyl alcohol-sodium butenoate composite catalyst at 3900-2400 cm⁻¹ -1 Infrared spectra in the high wavenumber region, stearyl alcohol at 3300 cm⁻¹ -1 A broad and strong absorption peak appears at [value missing], which is attributed to the stretching vibration of the -OH group in the stearyl alcohol molecule and is a characteristic peak of the hydroxyl group. In the stearyl alcohol-sodium butenoate composite catalyst, the peak shape of this -OH characteristic peak becomes significantly narrower, the absorption intensity decreases sharply, and the peak position shifts towards lower wavenumbers (marked by yellow arrows). This change directly proves that the hydroxyl group of stearyl alcohol and the carboxyl anion of sodium butenoate form intermolecular hydrogen bonding forces.
[0029] Figure 2 (b) Sodium butenoate and stearyl alcohol-sodium butenoate composite catalyst at 1700-1450 cm⁻¹ -1 Infrared spectrum of fingerprint region, sodium butenoate at 1560 cm⁻¹ -1 1410 cm -1 Two characteristic absorption peaks appear at this point, which are attributed to -COO. - The characteristic absorption peak is a hallmark of carboxylates; the stearyl alcohol-sodium butenoate composite catalyst retains the -COO peak. - The characteristic absorption peak (marked by the yellow arrow) was observed, but its position shifted slightly. This peak position change further confirms that the hydroxyl group of stearyl alcohol forms a hydrogen bond with the carboxyl group of sodium butenoate.
[0030] Example 2
[0031] (1) Sodium hydroxide and PEG600 are mixed in a molar ratio of 1:5. After they are completely mixed, they are heated at 200°C for 1 h to form a Lewis base-alcohol composite catalyst.
[0032] (2) Add 20 g of PHB with a weight-average molecular weight of 20 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:1500, and the reaction is carried out at 140℃ and a vacuum of 1 torr for 1 h. Collect the distillation product to obtain butenoic acid with a yield of 99.78% and a purity of 99.01%.
[0033] Example 3
[0034] (1) Sodium acetate and decanol were mixed in a molar ratio of 1:8 and heated at 180°C for 1.2 hours. Byproducts were removed by vacuum distillation to obtain Lewis base-alcohol composite catalyst.
[0035] (2) Add 25 g of waste PHB with a weight-average molecular weight of 40 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:1200. The reaction is carried out at 150°C and a vacuum of 2 torr for 1 hour. Collect the distillation product to obtain butenoic acid with a yield of 99.0% and a purity of 98.5%.
[0036] Example 4
[0037] (1) Sodium stearate and lauryl alcohol are mixed in a molar ratio of 1:5 and heated at 190°C for 1 hour to form a Lewis base-alcohol composite catalyst.
[0038] (2) 12 g of waste PHB with a weight-average molecular weight of 220 kDa was added to the reactor, and the Lewis base-alcohol composite catalyst synthesized in step (1) was added to the reactor. The mass ratio of catalyst to PHB was 1:800, and the reaction was carried out at 140 °C and a vacuum of 1 torr for 1.5 hours. The distillation product was collected to obtain butenoic acid with a yield of 99.5% and a purity of 99.0%.
[0039] Example 5
[0040] (1) 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphonobenzene (BTPP, organic strong base) and polyethylene glycol 400 are mixed in a molar ratio of 1:6 and heated at 145°C for 2.2 hours to form a Lewis base-alcohol composite catalyst.
[0041] (2) 28 g of waste PHB with a weight-average molecular weight of 120 kDa was added to the reactor, and the Lewis base-alcohol composite catalyst synthesized in step (1) was added to the reactor. The mass ratio of catalyst to PHB was 1:1000, and the reaction was carried out at 125 °C and a vacuum of 4 torr for 1.8 hours. The distillation product was collected to obtain butenoic acid with a yield of 99.3% and a purity of 99.0%.
[0042] Example 6
[0043] (1) 1,5-diazabicyclo[4.3.0]non-5-ene (DBN, an organic strong base) and palm oil alcohol are mixed at a molar ratio of 1:18 and heated at 165°C for 1.5 hours to form a Lewis base-alcohol composite catalyst.
[0044] (2) 15 g of waste PHB with a weight-average molecular weight of 260 kDa was added to the reactor, and the Lewis base-alcohol composite catalyst synthesized in step (1) was added to the reactor. The mass ratio of catalyst to PHB was 1:600, and the reaction was carried out at 155 °C and a vacuum of 0.5 torr for 0.8 hours. The distillation product was collected to obtain butenoic acid with a yield of 99.7% and a purity of 99.3%.
[0045] Example 7
[0046] (1) 1,8-diazabicycloundec-7-ene and oleyl alcohol are mixed at a molar ratio of 1:20 and heated at 170°C for 1 hour to form a Lewis base-alcohol composite catalyst.
[0047] (2) Add 40 g of waste PHB with a weight-average molecular weight of 30 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:1500, and the reaction is carried out at 110℃ and a vacuum of 2 torr for 2.5 hours. Collect the distillation product to obtain butenoic acid with a yield of 98.9% and a purity of 98.5%.
[0048] Example 8
[0049] (1) Potassium ethoxide and polyethylene glycol 1000 (PEG1000) are mixed at a molar ratio of 1:15 and heated at 180°C for 1 hour to form a Lewis base-alcohol composite catalyst.
[0050] (2) 20 g of waste PHB with a weight-average molecular weight of 150 kDa was added to the reactor, and the Lewis base-alcohol composite catalyst synthesized in step (1) was added to the reactor. The mass ratio of catalyst to PHB was 1:2000, and the reaction was carried out at 140 °C and a vacuum of 2 torr for 1.5 hours. The distillation product was collected to obtain butenoic acid with a yield of 99.2% and a purity of 98.8%.
[0051] Example 9
[0052] (1) Sodium isopropoxide and oleyl alcohol were mixed at a molar ratio of 1:25 and heated at 190°C for 1 hour. Byproducts were removed by vacuum distillation to obtain Lewis base-alcohol composite catalyst.
[0053] (2) 15 g of waste PHB with a weight-average molecular weight of 250 kDa was added to the reactor, and the Lewis base-alcohol composite catalyst synthesized in step (1) was added to the reactor. The mass ratio of catalyst to PHB was 1:2800, and the reaction was carried out at 110 °C and a vacuum of 8 torr for 2.8 hours. The distillation product was collected to obtain butenoic acid with a yield of 98.9% and a purity of 98.4%.
[0054] Example 10
[0055] (1) Sodium methoxide and docosyl alcohol were mixed in a molar ratio of 1:1 and heated at 145°C for 2 hours. The volatile components were removed by vacuum distillation to obtain the Lewis base-alcohol composite catalyst.
[0056] (2) Add 30 g of waste PHB with a weight-average molecular weight of 50 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:1000. The reaction is carried out at 120℃ and a vacuum of 5 torr for 2 hours. Collect the distillation product to obtain butenoic acid with a yield of 98.5% and a purity of 98.1%.
[0057] Example 11
[0058] (1) 4-Dimethylaminopyridine and palm oil alcohol were mixed at a molar ratio of 1:12 and heated at 175°C for 1.5 hours. After vacuum distillation, Lewis base-alcohol composite catalyst was obtained.
[0059] (2) Add 50 g of waste PHB with a weight-average molecular weight of 60 kDa to the reactor, and add the Lewis base-alcohol composite catalyst synthesized in step (1) to the reactor. The mass ratio of catalyst to PHB is 1:1000. The reaction is carried out at 145℃ and a vacuum degree of 4 torr for 1.2 hours to obtain butenoic acid with a yield of 99.3% and a purity of 99.1%.
[0060] Example 12
[0061] (1) Sodium isopropoxide and oleyl alcohol were mixed at a molar ratio of 1:25 and heated at 190°C for 1 hour. After vacuum distillation, Lewis base-alcohol composite catalyst was obtained.
[0062] (2) Add 20g of PHB with a weight-average molecular weight of 120 kDa to the reactor, and add the catalyst obtained in step (1). The mass ratio of catalyst to PHB is 1:100. Then add PHB at a feed rate of 20 g per hour. React for 10 hours at a reaction temperature of 145℃ and a vacuum of 3.5 torr. Collect the white substance distilled off at the tail end of the reactor to obtain butenoic acid with an average yield of 98.14% and a purity of 98.23%.
[0063] This invention provides a method for preparing functional chemicals from waste polyhydroxybutyrate. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.
Claims
1. A method of preparing functional chemicals from waste polyhydroxybutyrate, characterized in that, Includes the following steps: (1) A Lewis base-alcohol composite catalyst was prepared by mixing a Lewis base and a high-boiling-point alcohol and heating the mixture. (2) The Lewis base-alcohol composite catalyst obtained in step (1) is reacted with waste polyhydroxybutyrate to obtain butenoic acid.
2. The method of claim 1, wherein, In step (1), the Lewis base is an organic base and / or an inorganic base.
3. The method of claim 2, wherein, The organic base is any one of triethylamine, pyridine, 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, imidazole, 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphazene, 1,5-diazabicyclo[4.3.0]non-5-ene, triphenylphosphine, alkali metal alkoxides, or alkali metal carboxylates; the inorganic base is any one or more of alkali metal hydroxides, alkali metal carbonates, alkali metal phosphates, alkali metal borates, or alkaline earth metal hydroxides.
4. The method of claim 1, wherein, In step (1), the high-boiling-point alcohol is selected from any one of straight-chain saturated fatty alcohols, straight-chain unsaturated fatty alcohols, branched fatty alcohols, modified fatty alcohols, or polyol polymers with 10 to 30 carbon atoms.
5. The method according to claim 4, characterized in that, The straight-chain saturated fatty alcohol is any one of decanol, lauryl alcohol, stearyl alcohol, or docosyl alcohol; the straight-chain unsaturated fatty alcohol is any one of palm oil alcohol or oleyl alcohol; the branched fatty alcohol is an isomer alcohol, preferably Guerbert alcohol or carbonyl synthetic alcohol; the modified fatty alcohol is an ethoxylated alcohol; the polyol polymer is a polyether polyol with a molecular weight of 500 Da to 1500 Da, preferably, the polyether polyol is any one of polyethylene glycol or polypropylene glycol.
6. The method according to claim 1, characterized in that, In step (1), the molar ratio of the Lewis base to the high-boiling alcohol is 1:1 to 30.
7. The method according to claim 1, characterized in that, In step (1), the heating reaction is carried out at a temperature of 140~300℃ for a time of 0.5~3h.
8. The method according to claim 1, characterized in that, In step (2), the weight-average molecular weight of the waste polyhydroxybutyrate is 10 kDa to 600 kDa.
9. The method according to claim 1, characterized in that, In step (2), the mass ratio of the Lewis base-alcohol composite catalyst to waste polyhydroxybutyrate is 1:100~3000.
10. The method according to claim 1, characterized in that, In step (2), the reaction is carried out at a temperature of 100~160℃, a pressure of 0.5~10 torr, and a time of 0.5~3h.