Treatment method of polytrimethylene ether glycol polymerization reaction product

Abstract

The invention provides a treatment method of a polytrimethylene ether glycol polymerization reaction product, and belongs to the technical field of organic synthesis. According to the method, 1, 3-propylene glycol and an acid catalyst are mixed and then subjected to a polymerization reaction, a poly trimethylene ether glycol polymerization reaction product is obtained, and the reaction product comprises by-products such as ester; according to the method, a poly trimethylene ether glycol polymerization reaction product and water are mixed for hydrolysis reaction, by-products such as ester and the like can be hydrolyzed to form salt and alcohol, and the salt and the alcohol enter a water phase through liquid separation and are separated from a first organic phase; the first organic phase and the alkaline earth metal solution are mixed and then subjected to alkali washing, acidic impurities in the first organic phase can react, and further desulfurization is achieved; the second organic phase is subjected to flash evaporation treatment, moisture in the organic phase can be reduced, and the moisture content of the obtained third organic phase is 0.4-12%, so that the treatment amount of the third organic phase during rectification can be reduced, and the energy consumption required by rectification is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, in particular to a method for treating a polytrimethylene ether glycol polymerization product. Background Art

[0002] Polyurethane is a polymer resin prepared by the reaction of isocyanate and polyol. It has a wide range of applications in coatings, adhesives, fibers, plastics and elastic foams. The main classifications of polyols include ester type and ether type. Polytrimethylene ether glycol is an ether polyol based on oxetane or 1,3-propylene glycol. It is an ether type polyol substitute that can reduce greenhouse gases. Polytrimethylene ether glycol has a unique crystal structure. Compared with polyurethanes prepared from existing ether type polyols, polyurethanes prepared using polytrimethylene ether glycol have excellent elastic recovery, wear resistance and other properties, and have attracted widespread attention from researchers.

[0003] Currently, the preparation method for polytrimethylene ether glycol involves polymerizing an ether polyol in the presence of a catalyst, followed by post-treatment to remove residual catalyst impurities and other harmful substances. This results in high-quality polytrimethylene ether glycol with low moisture content, light color, no odor, and uniform properties. Common post-treatment methods include neutralization, adsorption, dehydration, filtration, and distillation. Specifically, neutralization involves adding an acidic or alkaline substance to neutralize residual catalyst. Adsorption involves adding an adsorbent to remove residual catalyst ions and colored substances. Ion exchange removes metal ions and other colored and toxic substances from the polyether polyol, significantly improving product quality. Filtration removes salts generated after catalyst neutralization. Distillation and conditioning are also required to obtain polyether products with low impurity content, light color, and a relatively narrow molecular weight distribution. During this process, antioxidants are added and trace moisture and other impurities are removed from the polyether, ultimately yielding a polyether polyol that meets quality requirements. However, in the above-mentioned post-treatment process, the neutralization process usually requires diluting the neutralizing agent to an appropriate concentration in order to better control the pH. It is inevitable that a large amount of water will be added, which will result in a large amount of energy consumption in the subsequent distillation process, and puts higher requirements on equipment and processing costs. Summary of the Invention

[0004] The object of the present invention is to provide a method for treating polytrimethylene ether glycol polymerization products with reduced energy consumption and lowered costs.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for treating a polytrimethylene ether glycol polymerization product, comprising the following steps:

[0007] After mixing 1,3-propylene glycol and an acid catalyst, a polymerization reaction is carried out to obtain a polytrimethylene ether glycol polymerization product;

[0008] mixing the polytrimethylene ether glycol polymerization product with water to perform a hydrolysis reaction, and separating the product obtained by the hydrolysis reaction to obtain a first organic phase;

[0009] The first organic phase is mixed with an alkaline substance and then subjected to alkaline washing, and then the product obtained by the alkaline washing is separated to obtain a second organic phase; the alkaline substance is an alkaline earth metal solution or an alkaline earth metal suspension;

[0010] flash evaporating the second organic phase to obtain a third organic phase; the water content of the third organic phase is 0.4 to 12%;

[0011] The third organic phase is distilled to obtain polytrimethylene ether glycol.

[0012] Preferably, the mass ratio of the polytrimethylene ether glycol polymerization product to water is 1:5 to 5:1.

[0013] Preferably, the temperature of the hydrolysis reaction is 70 to 90° C.; and the time of the hydrolysis reaction is 1 to 10 hours.

[0014] Preferably, the alkaline earth metal in the alkaline earth metal solution includes one or more of calcium, barium and magnesium.

[0015] Preferably, the concentration of the alkaline earth metal solution is 0.1-5 wt%.

[0016] Preferably, the mass ratio of the first organic phase to the alkaline earth metal solution is 5:1 to 1:5.

[0017] Preferably, the temperature of the alkali washing is 50-90° C.; and the time of the hydrolysis reaction is 1-10 h.

[0018] Preferably, the mass concentration of the acid catalyst is 30-98%; the mass percentage of the acid catalyst to 1,3-propylene glycol is 0.1-20%.

[0019] Preferably, the polymerization reaction temperature is 150-200° C.; and the polymerization reaction time is 12-36 hours.

[0020] Preferably, the device for flash treatment is a flash tank; a nozzle is provided in the middle of the flash tank; and the second organic phase is introduced into the flash tank through the nozzle.

[0021] The invention provides a method for treating a polytrimethylene ether glycol polymerization product. The method comprises the following steps: mixing 1,3-propylene glycol and an acid catalyst, performing a polymerization reaction, and obtaining a polytrimethylene ether glycol polymerization product; mixing the polytrimethylene ether glycol polymerization product with water, performing a hydrolysis reaction, and separating the product obtained by the hydrolysis reaction to obtain a first organic phase; mixing the first organic phase with an alkaline substance, performing an alkali wash, and then separating the product obtained by the alkali wash to obtain a second organic phase; the alkaline substance is an alkaline earth metal solution or an alkaline earth metal suspension; flash evaporating the second organic phase to obtain a third organic phase; the water content of the third organic phase is 0.4-12%; and rectifying the third organic phase to obtain polytrimethylene ether glycol. The present invention comprises mixing 1,3-propylene glycol and an acid catalyst and then subjecting them to a polymerization reaction to obtain a polytrimethylene ether glycol polymerization product. The reaction product includes byproducts such as esters formed by the reaction of the acid catalyst and the 1,3-propylene glycol. The present invention comprises mixing the polytrimethylene ether glycol polymerization product with water and subjecting it to a hydrolysis reaction to hydrolyze the esters into salts and alcohols. The salts and alcohols are then separated from the first organic phase by separation. The present invention further removes the catalyst from the first organic phase by mixing the first organic phase with an alkaline earth metal solution or suspension and then subjecting it to alkali washing. The present invention further removes the catalyst from the first organic phase by subjecting the second organic phase to a flash distillation treatment to reduce the water content of the organic phase, resulting in a water content of 0.4-12%. This reduces the amount of the third organic phase to be processed during distillation and reduces the energy consumption required for distillation. The results of the examples show that the method provided by the present invention can reduce the water content of the third organic phase to as low as 0.4%, significantly reducing the amount of distillation required for the third organic phase and, in turn, reducing the energy consumption required for distillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a front view of a nozzle of a flash tank used in an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of a cross section of a spray nozzle of a flash tank used in an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the flash tank used in the embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention provides a method for treating a polytrimethylene ether glycol polymerization product, comprising the following steps:

[0026] After mixing 1,3-propylene glycol and an acid catalyst, a polymerization reaction is carried out to obtain a polytrimethylene ether glycol polymerization product;

[0027] mixing the polytrimethylene ether glycol polymerization product with water to perform a hydrolysis reaction, and separating the product obtained by the hydrolysis reaction to obtain a first organic phase;

[0028] The first organic phase is mixed with an alkaline substance and then subjected to alkaline washing, and then the product obtained by the alkaline washing is separated to obtain a second organic phase; the alkaline substance is an alkaline earth metal solution or an alkaline earth metal suspension;

[0029] flash evaporating the second organic phase to obtain a third organic phase; the water content of the third organic phase is 0.4 to 12%;

[0030] The third organic phase is distilled to obtain polytrimethylene ether glycol.

[0031] The present invention mixes 1,3-propylene glycol and an acid catalyst, and then performs polymerization reaction to obtain a polytrimethylene ether glycol polymerization product.

[0032] In the present invention, the acid catalyst is preferably sulfuric acid, and the mass concentration of the sulfuric acid is preferably 50-98%, more preferably 70-98%. In the present invention, the mass percentage of the acid catalyst to the 1,3-propylene glycol is preferably 0.1-20%. As one embodiment of the present invention, the mass percentage of the acid catalyst to the 1,3-propylene glycol can be 0.1%, 0.3%, 0.5%, 0.6%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or 20%.

[0033] The present invention has no particular limitation on the method for mixing the 1,3-propylene glycol and the acid catalyst. Conventional methods can be used as long as the two are uniformly mixed.

[0034] In the present invention, the polymerization reaction temperature is preferably 150-200°C, more preferably 160-180°C. In the present invention, the polymerization reaction time is preferably 12-36 hours, more preferably 24-36 hours. Controlling the polymerization reaction temperature and time within the above ranges is more conducive to the complete polymerization of 1,3-propylene glycol to form polytrimethylene ether glycol.

[0035] After obtaining the polytrimethylene ether glycol polymerization product, the present invention mixes the polytrimethylene ether glycol polymerization product with water to perform a hydrolysis reaction, and separates the product obtained by the hydrolysis reaction to obtain a first organic phase.

[0036] In the present invention, the mass ratio of the polytrimethylene ether glycol polymerization product to water is preferably 1:5 to 5:1. As one embodiment of the present invention, the mass ratio of the polytrimethylene ether glycol polymerization product to water can be 1:1, 1:2, 1:3, 1:4, 1:5, 2:1, 2:3, 2:5, 3:1, 3:2, 3:4, 3:5, 4:1, 4:3, 4:5, 5:1, 5:2, 5:3, or 5:4. By mixing the polytrimethylene ether glycol polymerization product with water, the water can be used to hydrolyze byproducts such as esters produced by the reaction to form salts and alcohols. By controlling the mass ratio of the polytrimethylene ether glycol polymerization product to water within the above range, the present invention can fully remove byproducts.

[0037] In the present invention, the temperature of the hydrolysis reaction is preferably 70 to 90°C. As an embodiment of the present invention, the temperature of the hydrolysis reaction may be 70°C, 75°C, 80°C, 85°C or 90°C. In the present invention, the time of the hydrolysis reaction is preferably 1 to 10 hours. As an embodiment of the present invention, the time of the hydrolysis reaction may be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours. The present invention is more conducive to promoting a more complete hydrolysis reaction at the above temperature and time. In an embodiment of the present invention, the hydrolysis reaction is preferably carried out under stirring. The present invention does not specifically limit the stirring speed, and it can be adjusted as needed to promote sufficient contact between the polytrimethylene ether glycol polymerization reaction product and water.

[0038] The present invention is not particularly limited to the method for separating the product obtained by the hydrolysis reaction, and any conventional separation method can be used. The present invention can separate the organic phase and the aqueous phase through separation, so that the salt formed by the hydrolysis of the byproduct ester enters the aqueous phase to form an upper phase, which is separated from the lower first organic phase, thereby improving the purity of the polytrimethylene ether glycol in the first phase.

[0039] After obtaining the first organic phase, the present invention mixes the first organic phase with an alkaline earth metal solution and then performs alkali washing, and then separates the product obtained by the alkali washing to obtain a second organic phase.

[0040] In the present invention, the alkaline earth metal in the alkaline earth metal solution preferably includes one or more of calcium, barium, and magnesium, and more preferably one or more of calcium hydroxide, calcium oxide, barium hydroxide, barium oxide, magnesium hydroxide, and magnesium oxide. The present invention utilizes the above-mentioned alkaline earth metals to form an alkaline earth metal solution or an alkaline earth metal suspension. The present invention utilizes the alkaline earth metal solution to perform alkaline washing on the first organic phase, thereby further removing acidic impurities in the first organic phase.

[0041] In the present invention, the concentration of the alkaline earth metal solution is preferably 0.1 to 5 wt%. As an embodiment of the present invention. The concentration of the alkaline earth metal solution can be 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt% or 5 wt%. In the present invention, the mass ratio of the first organic phase to the alkaline earth metal solution is preferably 5:1 to 1:5. As an embodiment of the present invention, the mass ratio of the first organic phase to the alkaline earth metal solution can be 5:1, 5:2, 5:3, 5:4, 4:1, 4:3, 4:5, 3:1, 3:2, 3:4, 3:5, 2:1, 2:3, 2:5, 1:1, 1:2, 1:3, 1:4 or 1:5.

[0042] The present invention preferably adds an adsorbent to the mixture obtained by mixing the first organic phase with the alkaline earth metal solution before performing an alkali wash. In the present invention, the adsorbent preferably includes one or more of activated carbon, aluminosilicate, activated alumina, zeolite, and activated clay. In the present invention, the adsorbent preferably accounts for 0.1 to 3% of the mixture by weight. As one embodiment of the present invention, the adsorbent can account for 0.1%, 0.5%, 1%, 1.5%, or 3% of the mixture by weight.

[0043] In the present invention, the temperature of the alkali washing is preferably 50 to 90°C. As an embodiment of the present invention, the temperature of the alkali washing can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C. In the present invention, the time of the alkali washing is preferably 1 to 10 hours. As an embodiment of the present invention, the time of the alkali washing can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours. The present invention is more conducive to fully removing acidic impurities in the first organic phase at the above temperature and time. In the present invention, the alkali washing is preferably carried out under stirring.

[0044] The present invention does not particularly limit the method for separating the product obtained by alkali washing, and any conventional separation method can be used. The present invention can separate the system obtained after alkali washing into an upper phase and a lower phase through separation, wherein the lower phase is an organic phase and the upper phase is an aqueous phase, thereby improving the purity of the polytrimethylene ether glycol in the second phase.

[0045] In the present invention, the water content of the second organic phase is preferably 10-80%. As an embodiment of the present invention, the water content of the second organic phase can be 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%.

[0046] After obtaining the second organic phase, the second organic phase is subjected to flash treatment to obtain a third organic phase. In the present application, the water content in the third organic phase is 0.4-12%, preferably 0.4-2%. In the present application, the water content refers to the mass percentage of water.

[0047] In the present application, the flash treatment preferably comprises: preheating the second organic phase and then entering the flash tank through the nozzle for flash treatment. In the present application, the preheating temperature is preferably 60-90°C, more preferably 70-80°C. By preheating the second organic phase before flash treatment, the present application can improve the flash effect and remove most of the water in the second organic phase.

[0048] In the present application, the flash treatment temperature is preferably 150-250°C, more preferably 200-250°C; and the flash treatment time is preferably 1-20h, more preferably 5-15h.

[0049] The present application preferably filters while hot after the end of flash treatment to remove the adsorbent.

[0050] In the present application, the front view of the nozzle is preferably as shown in Figure 1 From Figure 1 It can be seen that the nozzle provided by the present application comprises a conical nozzle and a tubular cavity which are sequentially connected from bottom to top; and a nozzle thread is arranged at the connection between the conical nozzle and the tubular cavity. In the present application, the outlet diameter of the conical nozzle is smaller than the diameter of the tubular cavity. In an embodiment of the present application, the outlet diameter of the conical nozzle can be 1mm; the length of the conical nozzle can be 10.6mm; the radius of the nozzle thread can be 1 / 2 inch; the diameter of the tubular cavity can be 25.4mm; and the length of the tubular cavity can be 25.4mm. In an embodiment of the present application, the pressure in the flash tank can be 0.002MPa-0.02MPa. By using the above-mentioned nozzle, the second organic phase can enter the flash tank in a sprayed state, increasing the gas-liquid contact area. Under the low-pressure environment in the flash tank, the water contained in the second organic phase can be rapidly evaporated, preliminarily realizing efficient separation of water. Compared with conventional nozzles, the use of the above-mentioned nozzle can significantly improve the separation efficiency of water in the third organic phase, thereby significantly reducing the energy consumption caused by the removal of water in the third organic phase, and solving the problem of high energy consumption in the treatment of the polytrimethylene ether glycol polymerization product.

[0051] In the present application, the cross-sectional view of the nozzle is preferably as shown in Figure 2 From Figure 2 It can be seen that the nozzle provided by the present application is a ring nozzle, the diameter of the conical nozzle is smaller than the diameter of the tubular cavity, and the nozzle thread is arranged on the outer surface of the tubular cavity.

[0052] In the present invention, the schematic diagram of the flash tank is preferably as follows Figure 3 As shown. Figure 3 Among them, N1 is the vacuum port; N5 is the discharge port; N6 is the nitrogen port; N14 is the spray port; N2 and N3 are spare feeding ports; N7 and N8 are thermometers; N9 and N10 are liquid level gauges; 1 is the nozzle; 2 is the heating coil; 3 is the stirring paddle motor port; 4 is the packing layer; 5 is the support plate.

[0053] This invention incorporates a heating coil inside the flash tank. Water evaporation is an endothermic process, and the heating coil continuously replenishes heat, gradually raising the temperature of the second organic phase to the flash evaporation temperature. Furthermore, the use of a stirring device accelerates mass and heat transfer within the system, resulting in a uniform distribution of the temperature and concentration (water content) of the second organic phase, further increasing the water removal rate.

[0054] By installing a packing section at the top of the flash tank, the present invention addresses the problem of gas-liquid entrainment, which can easily occur during the flash evaporation process due to large amounts of water evaporation. Because the temperature inside the tank is higher than the boiling point of water at this pressure, water vapor does not condense, and any entrained liquid is effectively blocked by the packing and recirculated back into the solution, ensuring effective water removal and the integrity of the organic phase in the secondary organic phase. In embodiments of the present invention, the packing section can be filled with a packing selected from the group consisting of Pall rings, Super Raschig rings, plate corrugated packing, grid packing, and Optiflow packing.

[0055] The present invention provides a nitrogen inlet at the bottom of the flash tank. According to Dalton's law of partial pressures, the introduction of nitrogen significantly reduces the partial pressure of water vapor in the system, accelerating the evaporation of liquid water. The nitrogen flow agitates the liquid layer, further expanding the gas-liquid contact area and promoting the rapid migration of water from the liquid phase to the gas phase. Furthermore, the flowing nitrogen rapidly carries the evaporated water vapor out of the flash tank, effectively preventing condensation and reflux of water vapor within the tank, ensuring efficient and stable operation of the flash evaporation process.

[0056] After obtaining the third organic phase, the present invention performs rectification on the third organic phase to obtain polytrimethylene ether glycol.

[0057] The present invention has no particular limitation on the operating method of the distillation. Conventional distillation methods can be used to fully purify the polytrimethylene ether glycol for adjustment.

[0058] The method provided by the present invention can reduce impurities in the organic phase by first subjecting the polytrimethylene ether glycol polymerization product to a hydrolysis reaction and then performing alkali washing; and then significantly reduce the moisture in the organic phase through flash evaporation treatment, so that the moisture content of the obtained third organic phase is 0.4-12%. This can significantly reduce the volume of the third organic phase, reduce the liquid processing amount of distillation, and thus reduce production costs.

[0059] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0060] Example 1

[0061] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0062] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0063] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0064] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0065] After preheating the second organic phase to 70°C, pass through a nozzle (such as Figure 1 As shown) into the flash tank (as Figure 3 As shown), flash distillation was carried out at 180° C. and a vacuum degree of 0.095 MPa for 1 h to obtain a third organic phase with a water content of 1.4649%;

[0066] The third organic phase is distilled at 250-300° C. and 0.002 MPa to obtain polytrimethylene ether glycol. The final product has a water content of 1000 pppm, a molecular weight of about 1000, an acid value of ≤0.2 mgKOH / g, a hydroxyl value of 120-130 mgKOH / g, and a water content of less than or equal to 0.2%.

[0067] Example 2

[0068] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0069] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0070] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0071] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0072] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flashed for 3 hours at 180°C and a vacuum degree of 0.095 MPa to obtain a third organic phase with a water content of 0.6494%;

[0073] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0074] Example 3

[0075] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0076] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0077] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0078] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0079] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flash evaporated at 180°C and a vacuum of 0.095 MPa for 6 hours to obtain a third organic phase with a water content of 0.4237%;

[0080] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0081] Example 4

[0082] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0083] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0084] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0085] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0086] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flash evaporated at 180°C and a vacuum degree of 0.095 MPa for 8 hours to obtain a third organic phase with a water content of 0.400%;

[0087] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0088] Example 5

[0089] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0090] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0091] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0092] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0093] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flashed at 70°C and a vacuum degree of 0.095 MPa for 1 hour to obtain a third organic phase with a water content of 11.1240%;

[0094] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0095] Example 6

[0096] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0097] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0098] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0099] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0100] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flash evaporated at 70°C and a vacuum of 0.095 MPa for 3 hours to obtain a third organic phase with a water content of 10.5667%;

[0101] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0102] Example 7

[0103] A method for treating a polytrimethylene ether glycol polymerization product comprises the following steps:

[0104] 1,3-propylene glycol (≥97%) and sulfuric acid (98%) were mixed so that the mass percentage of the acid catalyst to the 1,3-propylene glycol was 0.6%, and polymerization reaction was carried out at 170° C. for 18 hours to obtain a polytrimethylene ether glycol polymerization product;

[0105] The polytrimethylene ether glycol polymerization product and water are mixed in a mass ratio of 1:1, stirred at 90° C. for 4 hours for hydrolysis reaction, and the product obtained by the hydrolysis reaction is separated to obtain an upper phase and a lower phase, wherein the lower phase is the first organic phase;

[0106] The first organic phase was mixed with an alkaline earth metal solution (0.5 wt% Ca(OH)2) in a mass ratio of 1:1, and the mixture was stirred at 60°C for 2 hours for alkali washing. The product obtained by the alkali washing was then separated to obtain an upper phase and a lower phase, wherein the lower phase was the second organic phase, and the water content of the second organic phase was 15%;

[0107] After preheating the second organic phase to 70°C, the phase enters a flash tank through a nozzle and is flash evaporated at 70°C and a vacuum of 0.095 MPa for 6 hours to obtain a third organic phase with a water content of 9.9773%;

[0108] The third organic phase is distilled (the distillation method is the same as that in Example 1) to obtain polytrimethylene ether glycol.

[0109] From the above results, it can be seen that the method provided by the present invention can significantly reduce the water content in the polytrimethylene ether glycol polymerization reaction product. Due to the significant reduction in the water content in the polytrimethylene ether glycol polymerization reaction product, the processing amount of the third organic phase during the distillation treatment can be significantly reduced, reducing energy consumption. The obtained polytrimethylene ether glycol has a high purity, solving the problem of high energy consumption in the preparation of polytrimethylene ether glycol.

[0110] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for treating a polytrimethylene ether glycol polymerization product, comprising the following steps: After mixing 1,3-propylene glycol and an acid catalyst, a polymerization reaction is carried out to obtain a polytrimethylene ether glycol polymerization product; mixing the polytrimethylene ether glycol polymerization product with water to perform a hydrolysis reaction, and separating the product obtained by the hydrolysis reaction to obtain a first organic phase; The first organic phase is mixed with an alkaline substance and then subjected to alkaline washing, and then the product obtained by the alkaline washing is separated to obtain a second organic phase; the alkaline substance is an alkaline earth metal solution or an alkaline earth metal suspension; flash evaporating the second organic phase to obtain a third organic phase; the water content of the third organic phase is 0.4 to 12%; The third organic phase is distilled to obtain polytrimethylene ether glycol.

2. The processing method according to claim 1, characterized in that The mass ratio of the polytrimethylene ether glycol polymerization product to water is 1:5 to 5:

1.

3. The processing method according to claim 1, characterized in that The temperature of the hydrolysis reaction is 70 to 90° C.; the time of the hydrolysis reaction is 1 to 10 hours.

4. The processing method according to claim 1, characterized in that The alkaline earth metal in the alkaline earth metal solution includes one or more of calcium, barium and magnesium.

5. The processing method according to claim 1 or 4, characterized in that: The concentration of the alkaline earth metal solution is 0.1-5 wt%.

6. The processing method according to claim 5, characterized in that The mass ratio of the first organic phase to the alkaline earth metal solution is 5:1 to 1:

5.

7. The processing method according to claim 1 or 4, characterized in that: The temperature of the alkali washing is 50-90° C.; the time of the hydrolysis reaction is 1-10 hours.

8. The processing method according to claim 1, characterized in that The mass concentration of the acid catalyst is 30-98%; the mass percentage of the acid catalyst to 1,3-propylene glycol is 0.1-20%.

9. The processing method according to claim 1 or 8, characterized in that: The polymerization reaction temperature is 150-200° C., and the polymerization reaction time is 12-36 hours.

10. The processing method according to claim 1, characterized in that: The flash evaporation method comprises: preheating the second organic phase and then passing the preheating phase into a flash evaporation tank through a nozzle for flash evaporation; the preheating temperature is 60-90°C.

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