CN106008932A - Novel method for preparing poly(butylene succinate) through melt polycondensation - Google Patents

Abstract

A novel method for preparing poly(butylene succinate) through melt polycondensation comprises the following steps: S11, adding 1,4-butanedioic acid and 1,4-butanediol into a reactor, and adding an appropriate amount of rare earth oxide serving as a main catalyst and a Na-X type molecular sieve serving as an assistant catalyst to form a mixture; S12, under the atmosphere of inert gas, rapidly raising temperature of the mixture under the stirring condition to 160 to 180 DEG C, and conducting reaction for 1 to 3 h; S13, under the vacuum condition, rapidly raising temperature of the product obtained in the step S12 to 200 to 240 DEG C, and stirring to conduct reaction for 1 to 4 h; S14, collecting the reaction product, taking out the reaction product while the reaction product is at the high temperature, and finally cooling the reaction product to the room temperature.

Description

A new method for the preparation of polybutylene succinate by melt polycondensation

technical field

The invention relates to a new method for preparing polybutylene succinate by melt polycondensation.

Background technique

The problem of global white pollution is becoming more and more serious, and biodegradable plastics have attracted more and more attention. Aliphatic polyester polymer materials have good biocompatibility and degradation performance, and have become the main development direction of biodegradable plastics. Among them, polybutylene succinate (PBS) has become a new biodegradable plastic with the most development potential due to its good mechanical properties and heat resistance.

However, the molecular weight obtained by a method for preparing polybutylene succinate in the prior art is relatively low, so that the obtained polybutylene succinate has low thermal stability.

Contents of the invention

The purpose of the present invention is to overcome the shortcoming of prior art, a kind of novel method that prepares polybutylene succinate by melting polycondensation is provided.

In order to solve the problems of the technologies described above, the present invention adopts the following technical measures:

The invention provides a kind of novel method preparing polybutylene succinate by melting polycondensation, comprising the following steps:

S11, weighing 1,4-butanedioic acid and 1,4-butanediol into the reactor, and adding an appropriate rare earth oxide as the main catalyst and Na-X type molecular sieve as the co-catalyst to form a mixture;

S12, under an atmosphere of an inert gas, rapidly raise the temperature of the mixture to 160° C. to 180° C. for 1 to 3 hours under stirring;

S13, under vacuum conditions, rapidly raise the product obtained in step S12 to 200-240° C., stir and react for 1-4 hours; and

S14, collecting the distillation reaction product, taking out the reaction product at high temperature, and finally cooling the reaction product to room temperature.

In order to further improve the technical solution, the present invention also includes the following technical features:

As a further improvement, in step S11, the 1,4-butanedioic acid and the 1,4-butanediol are mixed in a molar ratio of 1:1˜1.1.

As a further improvement, in step S12, the inert gas is nitrogen or a rare gas.

As a further improvement, in step S12, the mixture is rapidly heated to 170°C for 2 hours under stirring, wherein the temperature rise rate is 10-50°C/min, preferably, the temperature rise rate is 40-50°C /min.

As a further improvement, in step S13, the product obtained in step S12 is rapidly raised to 220-230°C for distillation reaction for 3 hours.

As a further improvement, the rare earth oxide is Nd ₂ O ₃ .

As a further improvement, the air pressure of the vacuum condition is less than or equal to 1kPa.

As a further improvement, in step S12, the mixture was rapidly heated to 170° C. for 2 h under stirring.

Polybutylene succinate provided by the invention and preparation method thereof have following advantages: one, adopt rare earth oxide catalyst as main catalyst, Na-molecular sieve is co-catalyst, then can synthesize high molecular weight polybutylene succinate with melting polycondensation method respectively Polybutylene succinate, so that described polybutylene succinate obtains good thermal stability; Its two, the method of the present invention fully utilizes raw material, has good industrialization prospect; Its three, the present invention The method has high success rate and good repeatability; four, the method of the present invention also has relatively simple synthesis steps and is easy to realize, wherein the melt polycondensation method does not need to use organic solvents in the synthesis process, which has advantages in environmental protection and is widely used. promote.

Description of drawings

Fig. 1 is the graph that the viscosity-average molecular weight of PBS changes with the reaction temperature in the new method for preparing polybutylene succinate by melt polycondensation provided by Examples 1 and 3 of the present invention.

Fig. 2 is the graph that the viscosity-average molecular weight of PBS changes with the reaction time in the new method for preparing polybutylene succinate by melt polycondensation provided by Examples 2 and 4 of the present invention.

3-4 are infrared spectrum curves of samples PBS3, PBS7, PBS13, and PBS18 provided by the examples of the present invention.

Fig. 5 is the nuclear magnetic resonance spectrum of the sample PBS 18 provided by the embodiment of the present invention.

Fig. 6 is the thermogravimetric curves of samples PBS3 and PBS7 provided by the embodiment of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The invention provides a kind of melt polycondensation method of polybutylene succinate, comprises the following steps:

S11, weighing 1,4-butanedioic acid and 1,4-butanediol into the reactor, and adding an appropriate rare earth oxide as the main catalyst and Na-X type molecular sieve as the co-catalyst to form a mixture;

S12, under an atmosphere of an inert gas, rapidly raise the temperature of the mixture to 160° C. to 180° C. for 1 to 3 hours under stirring;

S13, under vacuum conditions, rapidly raise the product obtained in step S12 to 200-240° C., stir and react for 1-4 hours; and

S14, collecting the distillation reaction product, taking out the reaction product at high temperature, and finally cooling the reaction product to room temperature.

In step S11, the 1,4-butanedioic acid and the 1,4-butanediol are preferably mixed according to a molar ratio of 1:1 to 1.1, which can avoid the reaction of the 1,4-butanediol Volatilization during the process leads to a decrease in yield. More preferably, the 1,4-butanedioic acid and the 1,4-butanediol are preferably mixed in a molar ratio of 1:1.05. Preferably, the mass ratio of the rare earth oxide to the Na-X molecular sieve is 1:0 to 1, more preferably, the mass ratio of the rare earth oxide to the Na-X molecular sieve is 1:0.5 to 1. In this embodiment, the mass ratio of the rare earth oxide to the Na-X molecular sieve is about 1:1, so that a good synergistic effect can be formed. The rare earth oxide is preferably Nd ₂ O ₃ .

In step S12, the polybutylene succinate (PBS) is mainly esterified into a small molecule polymer first. The inert gas can be nitrogen or rare gas. In addition, preferably, the mixture is rapidly heated to 170° C. for 2 h under stirring. The heating rate for rapid heating is 10-30°C/min. Wherein, the prepolymerization reaction is:

nHOOCCH ₂ CH ₂ COOH+(n+1)HO(CH ₂ ) ₄ OH

H-(O(CH ₂ ) ₄ OOC(CH ₂ ) ₂ CO) _n -O(CH ₂ ) ₄ OH+2nH ₂ O

In step S13, the polycondensation reaction is mainly completed under high vacuum conditions by increasing the reaction temperature. During the polycondensation process, the viscosity of the polyester gradually increases and water molecules are difficult to remove, so the solvent needs to be evaporated under reduced pressure to complete the polycondensation reaction. Preferably, the pressure of the vacuum condition is less than or equal to 1kPa. Wherein, polycondensation reaction is:

H-(O(CH ₂ ) ₄ OOC(CH ₂ ) ₂ CO) _n -O(CH ₂ ) ₄ OH+

H-(O(CH ₂ ) ₄ OOC(CH ₂ ) ₂ CO) _m -O(CH ₂ ) ₄ OH

H-(O(CH ₂ ) ₄ OOC(CH ₂ ) ₂ CO) _m+n -O(CH ₂ ) ₄ OH+HO(CH ₂ ) ₄ OH

Example 1:

1,4-butanedioic acid (AS) (9.01g, about 0.1mol), 1,4-butanediol (BD) (12.40g, about 0.105mol), rare earth oxide (Nd ₂ O ₃ ) (0.01 g), Na-X type molecular sieve (0.01g) joins in the three-necked round-bottomed flask of 250ml, installs polytetrafluoroethylene stirring bar, distillation unit, carries out oil bath under sufficient stirring, logical nitrogen protection, it is heated up to 170 rapidly ℃ reaction 2h. Afterwards, replace it with a vacuum distillation device, remove the nitrogen protection, and replace it with a vacuum device, and rapidly raise the temperature of the oil bath to 200°C, 210°C, 220°C, 230°C, and 240°C, and react at a constant temperature for 2 hours, then stop heating and stirring. Remove the three-neck flask, take out the product PBS while it is high temperature and cool it to room temperature. Please refer to Fig. 1 and Table 1, for calculating the relationship between the viscosity molecular weight of PBS1-PBS5 samples and the reaction temperature. It can be seen from Figure 1 and Table 1 that the optimum polycondensation reaction temperature is about 220°C.

Table 1 is the relational table of reaction temperature and PBS viscosity-average molecular weight in embodiment 1

Example 2:

1,4-butanedioic acid (AS) (9.01g, about 0.1mol), 1,4-butanediol (BD) (12.40g, about 0.105mol), rare earth oxide (Nd ₂ O ₃ ) (0.01 g), Na-X type molecular sieve (0.01g) joins in the three-necked round-bottomed flask of 250ml, installs polytetrafluoroethylene stirring bar, distillation unit, carries out oil bath under sufficient stirring, logical nitrogen protection, it is heated up to 170 rapidly ℃ reaction 2h. Afterwards, replace it with a vacuum distillation device, remove the nitrogen protection, and replace it with a vacuum device. The temperature of the oil bath is quickly raised to 220°C, and the constant temperature is respectively reacted for 2.0h, 2.5h, 3.0h, 3.5h and 4.0h, and the heating and stirring are stopped. Remove the three-neck flask, take out the product PBS while it is high temperature and cool it to room temperature. Please refer to Fig. 2 and Table 2, the relationship between the viscosity, molecular weight and reaction temperature of PBS11-PBS15 samples is obtained through calculation. It can be seen from Figure 2 and Table 2 that the optimal polycondensation reaction time is about 3h.

Table 2 is reaction time and PBS viscosity-average molecular weight relationship table in embodiment 2

Another embodiment of the present invention also provides a kind of preparation method that the molten solution of polybutylene succinate combines, comprises the following steps:

S21, weighing 1,4-butanedioic acid and 1,4-butanediol into the reactor, adding an appropriate rare earth oxide as the main catalyst, Na-X type molecular sieve as the co-catalyst and a solvent to form a mixture;

S22, rapidly raising the temperature of the mixture to 135° C. to 145° C. and reacting for 0.5 to 2 hours under the condition of stirring;

S23, distilling the solvent in the product obtained in step S22;

S24, under vacuum conditions, the product obtained in step S23 is rapidly raised to 200-240° C., and the reaction is distilled for 2-4 hours; and

S25, collecting the distillation reaction product, taking out the reaction product at high temperature, and finally cooling the reaction product to room temperature.

In step S21, the 1,4-butanedioic acid and the 1,4-butanediol are preferably mixed in a molar ratio of 1:1˜1.1. More preferably, the 1,4-butanedioic acid and the 1,4-butanediol are preferably mixed in a molar ratio of 1:1.05. The solvent is preferably an organic solvent that does not react with the 1,4-butanedioic acid and the 1,4-butanediol, such as toluene. Preferably, the mass ratio of the rare earth oxide to the Na-X molecular sieve is 1:0 to 1, more preferably, the mass ratio of the rare earth oxide to the Na-X molecular sieve is 1:0.5 to 1. In this embodiment, the mass ratio of the rare earth oxide to the Na-X molecular sieve is about 1:1, so that a good synergistic effect can be formed. The rare earth oxide is preferably Nd ₂ O ₃ .

In step S22, preferably, the mixture is heated rapidly to 140° C. for 1 h under stirring condition.

In step S24, the air pressure of the vacuum condition is less than or equal to 1 kPa.

In step S24, the product obtained in step S23 is rapidly raised to 220-230° C., and distilled for 3 hours.

Example 3:

1,4-butanedioic acid (SA) (9.01g, about 0.1mol), 1,4-butanediol (BD) (12.40g, about 0.105mol), rare earth oxide (0.01g, about 2.97×10 ^-5 mol), Na-X type molecular sieve (0.01g) and 25ml toluene join in the three-necked round-bottomed flask of 250ml, put into magnetic stirring bar, connect and be installed on the three-necked flask with spherical condensing tube and water separator, in Stir at 140 °C for 1 h. Then open the water trap piston, the solvent toluene is evaporated. Remove the water separation device and the reflux device and replace it with a vacuum distillation device. Rapidly raise the temperature of the oil bath to 200°C, 210°C, 220°C, 230°C and 240°C respectively, reduce the internal pressure to about 1kPa, keep the reaction at constant temperature for a certain period of time, stop heating and stirring, remove the three-necked flask, and take it out while it is hot The product is PBS, and it is stored after cooling to room temperature for later use. Please refer to Figure 1 and Table 3, for the relationship between the viscosity molecular weight and the reaction temperature of the PBS6-PBS10 samples obtained through calculation. It can be seen from Figure 1 and Table 3 that the optimum polycondensation reaction temperature is about 230°C.

Table 3 is the relation table between reaction temperature and PBS viscosity-average molecular weight in embodiment 3

Example 4:

1,4-butanedioic acid (SA) (9.01g, about 0.1mol), 1,4-butanediol (BD) (12.40g, about 0.105mol), rare earth oxide (0.01g, about 2.97×10 ^-5 mol), Na-X type molecular sieve (0.01g) and 25ml toluene join in the three-necked round-bottomed flask of 250ml, put into magnetic stirring bar, connect and be installed on the three-necked flask with spherical condensing tube and water separator, in Stir at 140 °C for 1 h. Then open the water trap piston, the solvent toluene is evaporated. Remove the water separation device and the reflux device and replace it with a vacuum distillation device. Rapidly raise the temperature of the oil bath to 230°C, reduce the internal pressure to about 1kPa, react at constant temperature for 2.0h, 2.5h, 3.0h, 3.5h, and 4.0h, stop heating and stirring, remove the three-necked flask, and take out the product PBS while it is hot , wait for it to cool to room temperature and store it for later use. Please refer to Figure 1 and Table 3, for the relationship between the viscosity molecular weight and reaction temperature of PBS16-PBS20 samples obtained through calculation. It can be seen from Figure 2 and Table 4 that the optimal polycondensation reaction time is about 3.0h.

Table 4 is reaction time and PBS viscosity-average molecular weight relationship table in embodiment 4

Please refer to Figure 3-4. Figure 3-4 is the infrared spectrum of samples PBS3, PBS7, PBS13, and PBS18 tested with a NICOCET IS10 Fourier transform infrared spectrometer (Nicoli Instruments, Inc., USA). As can be seen from the figure, the IR spectra in the two polymers are very similar. 2946cm ^-1 is the stretching vibration absorption peak of methylene (CH ₂ ), 1717cm ^-1 is the stretching vibration absorption peak of carbonyl (C=O), and 1387cm ^-1 is the bending vibration absorption peak of methylene (CH ₂ ) , 1209cm ^-1 and 1156cm ^-1 are CO stretching vibration absorption peaks. The existence of these characteristic absorption peaks proves that the obtained product is the expected product PBS.

Please refer to Figure 5. Figure 5 shows that the product PBS 18 is dissolved in 0.5ml of deuterated chloroform and detected by AMX200 Fourier transform nuclear magnetic resonance.

As shown in Figure 5, there are three main absorption peaks, the chemical shifts are δ=1.71 (m, 4H, CH ₂ CH ₂ CH ₂ CH ₂ ), δ=2.65 (t, 4H, OCOCH ₂ ), δ=4.09 (t, 4H, CH ₂ OCO), the area ratio is about 1:1:1, which proves that the sample is PBS.

Please refer to Fig. 6 together. Fig. 6 is a thermogravimetric analysis result of the above samples PBS3 and PBS7 using a NETZSCH STA409PC thermal analyzer (Netzsch, Germany), which is the following thermogravimetric diagram.

It can be seen from Figure 6 that PBS has a certain amount of mass loss between 20 and 300 °C. The rate of mass decline increases sharply after 315°C, and the temperature at which the weight loss ratio reaches 50% is 378°C. In addition, it can be seen that PBS begins to have a large mass loss phenomenon above 300°C. Since the processing and use temperature of PBS will not exceed 200°C, PBS is not easy to thermally decompose during processing and use. It shows that PBS has good thermal stability.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (10)

1. prepared a new method for poly butylene succinate by melt polycondensation, comprise the following steps:

S11, weighs 1, 4-succinic acid and BDO adds in reactor, and adds suitable rare earth oxide as sponsoring Agent and Na-X type molecular sieve form mixture as promoter；

S12, under the atmosphere of noble gas, is brought rapidly up described mixture to 160 DEG C～180 DEG C instead under conditions of stirring Answer 1～3h；

S13, under vacuum, product step S12 obtained is rapidly increased to 200～240 DEG C, stirring reaction 1-4h；With And

S14, collects distillation reaction product, and takes advantage of high temperature taking-up product, finally product is cooled to room temperature.

Method the most according to claim 1, it is characterised in that: in step s 11, described 1, 4-succinic acid and described 1, 4-butanediol mixes according to mol ratio 1: 1～1.1.

Method the most according to claim 2, it is characterised in that: in step s 11, described 1, 4-succinic acid and described 1, 4-butanediol mixes according to mol ratio 1: 1.05.

Method the most according to claim 1, it is characterised in that: in step s 12, described noble gas is nitrogen or rare Gas.

Method the most according to claim 1, it is characterised in that: in step s 12, by described mixture in the condition stirred Under be brought rapidly up to 170 DEG C reaction 2h.

Method the most according to claim 1, it is characterised in that: in step s 13, product step S2 obtained is rapid Rise to 220～230 DEG C of distillation reaction 3h.

Method the most according to claim 1, it is characterised in that: described rare earth oxide is Nd₂O₃。

Method the most according to claim 1, it is characterised in that: the air pressure of described vacuum condition is less than or equal to 1kPa.

Method the most according to claim 1, it is characterised in that: in step s 12, by described mixture in the condition stirred Under be brought rapidly up to 170 DEG C reaction 2h.

Method the most according to claim 1, it is characterised in that: described rare earth oxide and described Na-X type molecular sieve Mass ratio is 1: 0～1.