Preparation method of diallyl terephthalate

Abstract

The invention relates to the technical field of high polymer materials, in particular to a preparation method of diallyl terephthalate, which comprises the following steps: in the presence of a catalyst, reacting PET (Polyethylene Terephthalate) with allyl alcohol to obtain diallyl terephthalate; the catalyst is selected from antimony trioxide, sodium antimonate, aluminum trichloride, tetrabutyl titanate, tetraisopropyl titanate, zinc acetate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, pyridine, triethylamine, sodium methoxide, phosphoric acid, sulfuric acid and benzoic acid; and one or more of p-toluenesulfonic acid or sodium p-toluenesulfonate. The allyl alcohol is used as a PET alcoholysis agent, the waste PET is converted into diallyl terephthalate and ethylene glycol in the presence of a specific catalyst, an upgraded recovery route from the waste PET to a high-value optical monomer is realized, and meanwhile, low-cost and high-environmental-benefit synthesis of diallyl terephthalate is realized.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a method for preparing diallyl terephthalate. Background Art

[0002] Polyethylene terephthalate (PET) is one of the important general-purpose polymer materials after polyethylene, polypropylene, polyvinyl chloride and polystyrene, accounting for about 8% of the world's total polymer production, with an annual output of more than 70 million tons. Of this output, about 60% is used for chemical fiber textiles, and about 30% is used for packaging products such as bottles and sheets. The rigid terephthalate structure in the PET molecule gives it excellent mechanical properties and temperature resistance, but it also makes it extremely difficult to degrade in nature, becoming one of the main sources of white pollution. At present, the recycling and reuse rate of PET is still low, only about 14%. How to achieve efficient and high-value-added recycling of PET has always been a difficult problem.

[0003] Diallyl Terephthalate (DAT) is an optical resin monomer with extremely high economic value. The resin obtained by self-polymerization or copolymerization with other monomers has excellent mechanical properties, chemical resistance, heat resistance and optical properties. It is widely used in the manufacture of optical lenses, optical disks, optical fibers, optoelectronic devices, engineering plastics, etc. At present, there are few public methods for synthesizing diallyl terephthalate, and there are roughly two methods. One method is to use benzene or toluene as a water-carrying agent and use concentrated sulfuric acid to catalyze the reaction of terephthalic acid and allyl alcohol to prepare the target product. The other method is to prepare it by reacting sodium terephthalate with allyl chloride in the presence of CuCl. In the direct esterification method, benzene or toluene is azeotropic with water and allyl alcohol, and the proportion of allyl alcohol in the azeotrope is relatively large. Moreover, allyl alcohol is miscible with water, so the loss of allyl alcohol in the water-carrying process is extremely large. The main disadvantage of the sodium salt method is that sodium terephthalate has very low solubility in water and the reaction rate is very slow. In the alkaline system, allyl chloride hydrolyzes very quickly, so a multiple excess of allyl chloride is required, resulting in a waste of raw materials. In addition, wastewater containing allyl alcohol seriously pollutes the environment. Therefore, both methods are relatively expensive.

[0004] Alcoholysis of PET is an important PET recycling method. Through the transesterification reaction between the alcoholic hydroxyl groups in the raw material and the ester bonds in PET, PET can be depolymerized into the original monomer or other valuable compounds. Currently, there is no high recovery method for synthesizing diallyl terephthalate through alcoholysis of PET. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing diallyl terephthalate. The preparation method provided by the present invention can prepare diallyl terephthalate by alcoholysis of waste PET, and has a high waste PET recovery rate and a high diallyl terephthalate yield.

[0006] The present invention provides a method for preparing diallyl terephthalate, comprising the following steps:

[0007] In the presence of a catalyst, PET and allyl alcohol are reacted to obtain diallyl terephthalate;

[0008] The catalyst is selected from one or more of antimony trioxide, sodium antimonate, aluminum trichloride, tetrabutyl titanate, tetraisopropyl titanate, zinc acetate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, pyridine, triethylamine, sodium methoxide, phosphoric acid, sulfuric acid, benzoic acid, p-toluenesulfonic acid or sodium p-toluenesulfonate, preferably one or more of potassium carbonate, tetrabutyl titanate or zinc acetate.

[0009] In the present invention, PET and allyl alcohol are reacted under the specific catalyst as described above to obtain diallyl terephthalate, wherein the PET is waste PET; the number average molecular weight of the PET is greater than 5000 and less than 100000. The reaction process of the preparation method of diallyl terephthalate provided by the present invention is shown in Formula I:

[0010] Formula Ⅰ.

[0011] More specifically, the present invention reacts a catalyst, PET and allyl alcohol in a sealed reaction container, and after the reaction, the product obtained by the reaction is subjected to atmospheric distillation to recover excess allyl alcohol, and the undistilled high boiling point portion is collected, and the undistilled high boiling point portion is filtered to remove solid impurities, and then the product is purified by silica gel column chromatography and decolorized to obtain diallyl terephthalate. The temperature of the atmospheric distillation of the present invention is 100-120° C., preferably 110° C. The eluent used for the silica gel column chromatography of the present invention is dichloromethane.

[0012] The molar ratio of PET to allyl alcohol of the present invention is 1:(8-32), and the amount of the catalyst is 1 mol%-25 mol% of the amount of PET. Preferably, the molar ratio of PET to allyl alcohol is 1:(14-32), and the amount of the catalyst is 1 mol%-25 mol% of the amount of PET. More preferably, the molar ratio of PET to allyl alcohol is 1:(14-32), and the amount of the catalyst is 10 mol%-25 mol% of the amount of PET.

[0013] The temperature of the reaction of the present invention is above 90°C, and the reaction time is above 1 h. Preferably, the temperature of the reaction is 120°C to 240°C, and the reaction time is 1 h to 72 h. In some embodiments of the present invention, the temperature of the reaction is 180°C to 240°C, and the reaction time is 1 h to 10 h. In other embodiments of the present invention, the temperature of the reaction is 120°C to 140°C, and the reaction time is 48 h to 72 h.

[0014] The invention provides a preparation method of diallyl terephthalate, comprising the following steps: reacting PET and allyl alcohol under a catalyst to obtain diallyl terephthalate; the catalyst is selected from one or more of antimony trioxide, sodium antimonate, aluminum trichloride, tetrabutyl titanate, tetraisopropyl titanate, zinc acetate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, pyridine, triethylamine, sodium methoxide, phosphoric acid, sulfuric acid, benzoic acid, p-toluenesulfonic acid or sodium p-toluenesulfonate. The invention uses allyl alcohol as an alcoholysis agent for PET, and under the action of a specific catalyst, the waste PET is converted into diallyl terephthalate and ethylene glycol. The conversion method realizes an upgraded recycling route from waste PET to a highly valuable optical monomer, and at the same time realizes the synthesis of diallyl terephthalate with low cost and high environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the H NMR spectrum of the alcoholysis reaction stock solution of Example 8 of the present invention;

[0016] Figure 2 This is the H NMR spectrum of the purified diallyl terephthalate of Example 8 of the present invention. DETAILED DESCRIPTION

[0017] The present invention discloses a method for preparing diallyl terephthalate. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the same. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to achieve and apply the technology of the present invention.

[0018] The present invention will be further described below in conjunction with embodiments:

[0019] Example 1

[0020] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to 90°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 72 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 24%. The product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 23%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0021] Example 2

[0022] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 100°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 48 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 29%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 28%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0023] Example 3

[0024] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 110°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 48 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 42%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 40%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0025] Example 4

[0026] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 120°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 48 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 51%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 48%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0027] Example 5

[0028] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 130°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 48 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 66%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 63%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0029] Example 6

[0030] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 140°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 48 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 80%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 75%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0031] Example 7

[0032] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 87%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 83%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0033] Example 8

[0034] Add PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.25) into a pressure-resistant reactor equipped with a magnetic stirrer, and then seal the reactor. Place the reactor in an oil bath equipped with a magnetic stirrer, control the reaction temperature to 220°C, the magnetic stirring speed to 400 rpm, and continue the reaction for 2 hours. After the reaction is completed, fully cool the reactor to room temperature, then open the reactor to collect the product. Detect the liquid product by hydrogen nuclear magnetic resonance spectroscopy, such as Figure 1 As shown, Figure 1 The hydrogen nuclear magnetic spectrum of the alcoholysis reaction stock solution of Example 8 of the present invention is shown in FIG. 1 , and the yield of diallyl terephthalate is calculated to be 96%. The liquid product is placed in an atmospheric distillation apparatus, and the excess allyl alcohol is recovered at a heating temperature of 110° C. The obtained allyl alcohol is a colorless transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol is >99% as detected by hydrogen nuclear magnetic resonance spectrum technology. The undistilled high-boiling-point portion in the atmospheric distillation apparatus is collected and filtered to remove solid impurities. The product is then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product is collected with a yield of 91%. The hydrogen nuclear magnetic resonance spectrum results show that its structure is diallyl terephthalate, as shown in FIG. Figure 2 As shown, Figure 2 This is the H NMR spectrum of the purified diallyl terephthalate of Example 8 of the present invention.

[0035] Example 9

[0036] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 72%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 69%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0037] Example 10

[0038] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.01) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 49%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 47%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0039] Embodiment 11

[0040] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:16:0.50) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 93%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 89%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0041] Example 12

[0042] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:4:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 44%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 42%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0043] Embodiment 13

[0044] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:8:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 61%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 58%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0045] Embodiment 14

[0046] PET, allyl alcohol, and potassium carbonate (molar ratio, PET: allyl alcohol: potassium carbonate = 1:32:0.25) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 96%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 90%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0047] Embodiment 15

[0048] PET, allyl alcohol, and zinc acetate (molar ratio, PET: allyl alcohol: zinc acetate = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 69%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 64%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0049] Example 16

[0050] PET, allyl alcohol, and tetrabutyl titanate (molar ratio, PET: allyl alcohol: tetrabutyl titanate = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 73%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 67%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0051] Embodiment 17

[0052] PET, allyl alcohol, and potassium hydroxide (molar ratio, PET: allyl alcohol: potassium hydroxide = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 49%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 45%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0053] Embodiment 18

[0054] PET, allyl alcohol, and sodium hydroxide (molar ratio, PET: allyl alcohol: sodium hydroxide = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 38%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 34%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0055] Embodiment 19

[0056] PET, allyl alcohol, and triethylamine (molar ratio, PET: allyl alcohol: triethylamine = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 24%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 21%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0057] Embodiment 20

[0058] PET, allyl alcohol, and dibutyltin oxide (molar ratio, PET: allyl alcohol: dibutyltin oxide = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 47%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 42%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0059] Embodiment 21

[0060] PET, allyl alcohol, and sodium ethoxide (molar ratio, PET: allyl alcohol: sodium ethoxide = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 37%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 35%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0061] Embodiment 22

[0062] PET, allyl alcohol, and antimony oxide (molar ratio, PET: allyl alcohol: antimony oxide = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 31%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 29%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0063] Embodiment 23

[0064] PET, allyl alcohol, and sodium bicarbonate (molar ratio, PET: allyl alcohol: sodium bicarbonate = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 23%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 20%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0065] Embodiment 24

[0066] PET, allyl alcohol, and pyridine (molar ratio, PET: allyl alcohol: pyridine = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to be 180°C, the magnetic stirring speed was 400rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be 61%. The liquid product was placed in an atmospheric distillation device, and the excess allyl alcohol was recovered at a heating temperature of 110°C. The obtained allyl alcohol was a colorless and transparent liquid with a recovery rate of >98%. The purity of the recovered allyl alcohol was >99% detected by nuclear magnetic resonance hydrogen spectrum technology. The high boiling point part that was not distilled in the atmospheric distillation device was collected and filtered to remove solid impurities. The product was then purified and decolorized by silica gel column chromatography (eluent: dichloromethane), and a colorless transparent product was collected with a yield of 55%. The results of hydrogen nuclear magnetic resonance spectroscopy showed that its structure was diallyl terephthalate.

[0067] Comparative Example 1

[0068] PET, allyl alcohol, and titanium tetrachloride (molar ratio, PET: allyl alcohol: titanium tetrachloride = 1:16:0.10) were added to a pressure-resistant reactor equipped with a magnetic stirrer, and then the reactor was sealed. The reactor was placed in an oil bath equipped with a magnetic stirring device, the reaction temperature was controlled to 180°C, the magnetic stirring speed was 400 rpm, and the reaction was continued for 8 hours. After the reaction was completed, the reactor was fully cooled to room temperature, and then the product was collected. The liquid product was detected by nuclear magnetic resonance hydrogen spectrum technology, and the yield of diallyl terephthalate was calculated to be less than 1%.

[0069] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing diallyl terephthalate, characterized in that: The following steps are involved: In the presence of a catalyst, PET and allyl alcohol are reacted to obtain diallyl terephthalate; The catalyst is selected from one or more of antimony trioxide, sodium antimonate, aluminum trichloride, tetrabutyl titanate, tetraisopropyl titanate, zinc acetate, zinc chloride, dibutyltin dilaurate, aluminum trichloride, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, pyridine, triethylamine, sodium methoxide, phosphoric acid, sulfuric acid, benzoic acid, p-toluenesulfonic acid or sodium p-toluenesulfonate.

2. The preparation method according to claim 1, characterized in that: The PET is waste PET.

3. The preparation method according to claim 1, characterized in that: The number average molecular weight of the PET is greater than 5,000.

4. The preparation method according to claim 1, characterized in that: The molar ratio of PET to allyl alcohol is 1:(8-32).

5. The preparation method according to claim 4, characterized in that: The molar ratio of PET to allyl alcohol is 1:(14-32).

6. The preparation method according to claim 1, characterized in that: The amount of the catalyst used is 1 mol% to 25 mol% of the amount of PET used.

7. The preparation method according to claim 6, characterized in that: The amount of the catalyst used is 10 mol% to 25 mol% of the amount of PET used.

8. The preparation method according to claim 1, characterized in that: The reaction temperature is above 90° C., and the reaction time is above 1 h.

9. The preparation method according to claim 8, characterized in that: The reaction temperature is 120° C. to 240° C., and the reaction time is 1 h to 72 h.

10. The preparation method according to any one of claims 1 to 9, characterized in that: After the reaction, the product obtained by the reaction is subjected to atmospheric distillation, and the undistilled high-boiling point portion is collected to obtain diallyl terephthalate; the temperature of the atmospheric distillation is 100-120°C.

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