TWI423993B - A method for polyesterification by tin catalysts - Google Patents

Description

Method for using tin-containing catalyst for polyesterification reaction

The present invention relates to a method for a polyesterification reaction of a tin-containing catalyst, and more particularly to a method for improving the catalytic efficiency of a tin-containing catalyst to accelerate the formation of a polyester-based polymer.

At present, in the industrial operation of the esterification and polyesterification reaction, a metal-containing compound is often used as a catalyst, such as a compound such as aluminum, titanium, lithium or tin, thereby shortening the time required for the esterification and polyesterification reaction.

Among them, tin compounds are more widely used as catalysts, and the tin compound includes stannous isooctanoate, stannous chloride, stannous sulfate, dibutyltin oxide, and the like. Taking the stannous isooctylate as an example, it is possible to obtain a higher molecular weight polymer at a high conversion rate with a lower amount. However, the stannous isooctylate itself has a low catalytic activity and must undergo a long-term high-temperature reaction in order to exert the complete catalytic effect of the stannous isooctylate to obtain a polymer having a desired high molecular weight, so the isooctanoic acid The process of stannous catalyzed polyesterification often requires a large amount of energy and time, and relatively increases the cost burden of subsequent finished products.

Here, most of the companies actively develop a catalyst which is more capable of replacing the stannous isooctylate in addition to the above tin compound, in order to obtain a preferable catalytic effect in the polyesterification reaction.

For example, the Patent No. 200301273 of the Republic of China, "methyl tin catalyst for polyesterification reaction", discloses a methyl tin compound as a catalyst in high temperature esterification and polyesterification reaction. The methyl tin compound catalyzes the ester and polyester obtained to have excellent physical/chemical properties to improve the color and thermal stability of the ester and polyester, and is suitable for multi-stage polyesterification. However, the methyl tin compound disclosed in the prior patent can only change the physical and chemical properties of the product produced by the subsequent polyesterification reaction, and even must be subjected to a high temperature of 200 degrees Celsius or longer for a long time to reach the polyester. The preferred catalytic effect of the reaction process is still unable to improve the above-mentioned problems, and the increase in the reaction temperature relatively increases the cost of the overall polyesterification reaction process.

Further, although the above-mentioned conventional patents use other metal-containing compounds as catalysts for the polyesterification reaction, there has been no significant breakthrough in catalytic efficiency. Even most catalysts tend to react with air or oxygen in the air under the action of air, thereby reducing the catalytic effect of the catalyst. Not only does it have low air sensitivity like the stannous isooctylate, but it is not even capable of ring-opening polymerization of unpurified ester compounds under air, so that the processes of the catalysts in the polyesterification reaction are obvious. There are more restrictions. Therefore, at this stage, the process of operating the polyesterification reaction to produce a polyester-based polymer in the industry has always been based on a tin compound such as stannous isooctylate as a main catalyst, and so far, it has not been possible to improve the catalysis of the tin-containing catalyst as described above. The efficiency is not plagued.

In view of the above, it is indeed necessary to develop a method of using a tin-containing catalyst for the polyesterification reaction in order to improve the catalytic efficiency of the tin-containing catalyst in the polyesterification reaction, and to solve various problems as described above.

The main object of the present invention is to improve the above disadvantages to provide a tin-containing catalyst for a polyesterification reaction, which is capable of increasing the catalytic activity of the tin-containing catalyst to enhance the tin-containing catalyst in the polyesterification reaction. Catalytic efficiency.

A second object of the present invention is to provide a method for the polyesterification reaction of a tin-containing catalyst, which is capable of maintaining the low sensitivity of the tin-containing catalyst to air to ensure the catalytic effect of the tin-containing catalyst in the polyesterification reaction. .

In order to attain the foregoing object, the method for the method for the polyesterification reaction of the tin-containing catalyst of the present invention comprises: a mixing step of a N,N-dialkylformamidine dialkyl acetal reagent Mixing a tin-containing catalyst to transfer the alkoxy group bonded by the N,N-dialkylformamide dialkyl acetal reagent to the tin-containing catalyst to obtain a tin-containing catalyst complex; a polymerization step of catalyzing a ring-opening polymerization of an ester compound by the tin-containing catalyst complex to form a polyester-based polymer; wherein the N,N-dialkylformamide dialkyl is reduced The aldehyde reagent is a compound represented by Chemical Formula 1, and the R system of the Chemical Formula 1 is an alkyl group.

(RO) ₂ CHNR ₂ [Chemical Formula I]

Wherein the N,N dialkylformamidine dialkyl acetal reagent is N,N-dimethylformamide dimethyl acetal or N,N-dimethylformamide diethyl The acetal, the tin-containing catalyst is stannous isooctylate, stannous sulfate, stannous chloride or dibutyltin oxide. Furthermore, the molar concentration of the tin-containing catalyst is 0.0025 to 0.08 M, and the mixing ratio of the tin-containing catalyst to the N,N-dialkylformamide dialkyl acetal reagent is 1:1. .

The above and other objects, features, and advantages of the present invention will become more apparent from the aspects of the appended claims. It is a preferred embodiment of the present invention, and the method for using a tin-containing catalyst for a polyesterification reaction comprises a mixing step S1 and a polymerization step S2.

The mixing step S1 is to mix a N,N-dialkylformamidine dialkyl acetal reagent with a tin-containing catalyst to bond the N,N-dialkylformamidine dialkyl acetal reagent. The alkoxy group is transferred to the tin-containing catalyst to obtain a tin-containing catalyst complex. Here, the N,N dialkylformamidine dialkyl acetal reagent is a compound represented by Chemical Formula 1, and R in the Chemical Formula 1 is an alkyl group.

(RO) ₂ CHNR ₂ [Chemical Formula 1]

More specifically, the N,N-dialkylformamidine dialkyl acetal reagent is mixed with the tin-containing catalyst to form the tin-containing catalyst complex, and the tin-containing catalyst complex is easily released. A substance similar to a polymerization initiator can be applied to the subsequent polymerization step S2 to carry out ring-opening polymerization of an ester compound without additionally adding a polymerization initiator such as benzyl alcohol. reaction. Wherein, the tin-containing catalyst may be selected from stannous isooctanoate, stannous chloride, stannous sulfate, dibutyltin oxide, etc., and the N,N-dialkylformamidine dialkyl acetal reagent system It may be selected from N,N-dimethylformamide dimethyl acetal (DMF-DMA) or N,N-dimethylformamide diethyl acetal (DMF-DEA).

This embodiment is preferably selected as N,N-dimethylformamide dimethyl acetal, so that the methoxy group on the N,N-dimethylformamide dimethyl acetal can be easily transferred. To the tin-containing catalyst, a tin-containing catalyst complex having a relatively stable structure is formed. Moreover, since the ring-opening polymerization reaction of the ester compound mainly uses a methoxy group as a polymerization starting end, the methoxy group bonded to the terminal of the tin-containing catalyst complex can be used as a polymerization initiator, and In the polymerization step S2, a preferred effect of ring-opening polymerization of the ester compound is exhibited.

The present invention uses DMF-DMA as an abbreviation for the N,N-dimethylformamide dimethyl acetal in the following. For example, in this embodiment, the DMF-DMA reagent is first mixed with stannous isooctylate in a toluene solvent at a ratio of 1:1, and gradually heated to a temperature of 100 ° C for half an hour, after being vacuum-dried. After the volatile matter, the organic solvent layer after the reaction is washed away by adding n-hexane to form the stannous isooctanoate complex in the form of an oil. Spectral analysis was carried out as a result, and the spectrum of the stannous isooctylate (C) and the stannous isooctanoate (B) and DMF-DMA reagent (A) was carried out as shown in Figures 2a to 2b. In comparison, it is apparent that the a and c signals originally present in the (A) spectrum disappear in the (C) spectrum, and only the methoxy signal in the DMF-DMA reagent remains (as shown in (C) b signal), and (B) spectrum of stannous isooctanoate signal. Wherein, the a, b and c signals appearing in the spectrum of the DMF-DMA reagent (A) are shown in Figure 2b, where a represents hydrogen bonded to the carbon atom bonded to the nitrogen group; b represents The hydrogen bonded to the carbon atom bonded to the oxy group; c represents the hydrogen bonded to the carbon atom of the main structure.

In order to better understand how the DMF-DMA reagent system changes the structure of the tin-containing catalyst, please refer to the second and second graphs, and analyze the spectrum (D) with tin dichloride mixed with DMF-DMA. It can be seen that only the signals of the two groups of methoxy d, e appear in the (D) spectrum, possibly by the one-methoxy group participating in the bridging bond (such as the e part shown in Fig. 2c), and the other methoxy group. The base dangling is bonded to the tin element of the tin dichloride (as part d shown in Fig. 2c); and, by the Sn ¹¹⁹ NMR spectrum, the difference between the DMF-DMA reagents is obtained. The stannous octoate complex has little change in the shift on the NMR spectrum compared to the stannous isooctylate, so the tin element in the stannous isooctylate complex still maintains a divalent state, confirming the difference The stannous octoate complex is only formed by the methoxy group bonded by the DMF-DMA reagent and the oligomer formed by the substitution of the isooctanoic acid group bonded by the stannous isooctylate. Figure 3 shows. Thereby, the stannous isooctylate can be synthesized into the stannous isooctanoate complex rich in methoxy group by the action of the DMF-DMA reagent to enhance the catalytic activity of the stannous isooctanoate itself.

The polymerization step S2 catalyzes the ring-opening polymerization of the ester compound through the tin-containing catalyst complex to form a polyester-based polymer. More specifically, the tin-containing catalyst complex has an alkoxy end to permeate the alkoxy end to the polymerization starting point of the ester compound, and the ester compound is opened to change the ester. The bond sequence of the compound can be converted from a cyclic monomer to a linear monomer, and gradually polymerized into a high molecular weight polymer.

For example, in this embodiment, the stannous isooctanoate complex formed by the mixing step S1 is mixed with 25 times of cyclocaprolactone, so that the cyclocaprolactone can be mixed in a sufficient amount of the stannous isooctanoate. Under the catalysis of the catalyst, the ring structure of the cyclocaprolactone is opened to generate a new bond connection sequence between the elements, ions or molecules of the cyclohexanolide, and is converted into a linear cyclocaprolactone monomer. Further, the methoxy group rich in the stannous isooctylate complex is used as a polymerization initiator to start a continuous and stepwise polymerization reaction, thereby accelerating the ring-opening polymerization of the cyclocaprolactone to form a high molecular weight polycondensation. The preferred effect of cyclocaprolactone. Further, in the mixing step S1, the tin-containing catalyst is mixed with the DMF-DMA reagent to form various tin-containing catalyst complexes to polyesterize the cyclocaprolactone and lactide. The chemical reaction formula is detailed in (A) and (B) of Fig. 4, wherein (A) refers to the polyesterification reaction of the cyclocaprolactone, and (B) refers to the polyester of the lactide. Reaction. Further, the polymerization step S2 is preferably carried out by reacting in a solvent, which is selected in particular as toluene, whereby a preferred polymerization effect of the ester compound is achieved.

It is known from the above that the method for the polyesterification reaction of the tin-containing catalyst of the present invention can be preceded by the reaction of the N,N-dialkylformamidine dialkyl acetal reagent with the tin-containing catalyst. And forming the tin-containing catalyst complex having a new bonding structure, and the tin-containing catalyst complex has an alkoxy end sufficient to initiate ring-opening polymerization of the ester compound, thereby greatly increasing the tin-containing Catalyst activity of the catalyst, and the polyesterification reaction of the ester compound can be rapidly carried out without adding a polymerization initiator, so as to generate a high molecular weight polyester polymer at a lower temperature, Improve the efficiency of the polyesterification reaction.

Furthermore, the addition of the N,N dialkylformamidine dialkyl acetal reagent only has a change in the bonding structure, and the divalent state of the tin element of the tin-containing catalyst itself can be maintained without affecting The sensitivity of the tin-containing catalyst to air, so that the N,N-dialkylformamide dialkyl acetal reagent and the tin-containing catalyst complex formed by the tin catalyst can be retained in the present invention. The tin-containing catalyst preferably has physical and chemical properties to ensure that the tin-containing catalyst complex still has low air sensitivity, and can be exposed to air to carry out polyesterification reaction of the ester compound without There are excessive limitations in the progress of the polyesterification reaction.

In order to confirm the method for the polyesterification reaction of the tin-containing catalyst of the present invention, the activity of the tin-containing catalyst can be improved, and the ring-opening polymerization reaction of the ester compound is accelerated in a short time with a preferred catalytic efficiency. For the lower temperature reaction process, a high molecular weight polyester polymer is obtained.

The present invention is directed to the polymerization of cyclocaprolactone and lactide, and the following experiments and analyses are separately performed, thereby observing the catalytic reaction time (minutes) and conversion rate (%) of the tin-containing catalyst, and permeating through the gel. The molecular weight and molecular weight distribution (PDI) of the polyester polymer were analyzed by chromatography (GPC).

Referring to Table 1-1, it is a case where a tin-containing catalyst catalyzes the formation of a polymer of cyclocaprolactone, and the N,N-dialkylformamide dialkyl acetal reagent of the present embodiment is selected as N. N-dimethylformamide dimethyl acetal (DMF-DMA); the tin-containing catalyst comprises stannous isooctylate, stannous sulfate, stannous chloride and dibutyltin oxide, and the tin is contained The molar concentration of the catalyst is preferably 0.08 M. Herein, the DMF-DMA reagent is separately mixed with the tin-containing catalysts in different proportions, and then benzyl alcohol (BnOH) is selectively added as a polymerization initiator to react with the unadded DMF-DMA. For comparison, 10 ml of toluene was added as a solvent in an environment of 100 ° C to carry out ring-opening polymerization of cyclohexylide (ε-caprolactone, CL). Among them, the weight molar concentration of the cyclocaprolactone is preferably selected to be 2M.

Table 1-1: The case where the tin-containing catalyst catalyzes the formation of a polymer from cyclocaprolactone.

From the results of Table 1-1, no matter which of the selected tin-containing catalysts is selected, the group of DMF-DMA reagents (A1, B1, C1, and the like) are added during the ring-opening polymerization of the cyclocaprolactone. D1), the conversion of the cyclohexanolide at the same time compared to the group (A2, B2, C2, and D2) to which the DMF-DMA reagent was not added with the addition of the benzyl alcohol as a polymerization initiator The rate is markedly improved, thereby demonstrating that the addition of the DMF-DMA reagent can greatly enhance the activity of the tin-containing catalyst itself. And only at a low temperature of 100 degrees Celsius, the effect of accelerating the ring-opening polymerization of the cyclocaprolactone to form polycyclocaprolactone can be achieved.

In addition, please refer to Table 1-2, which is a case where a tin-containing catalyst catalyzes the formation of a high molecular weight polymer by cyclohexanolide. In this embodiment, stannous isooctylate is selected as a catalyst at a temperature of 140 degrees Celsius. 2500 times of cyclocaprolactone was added, and the DMF-DMA reagent was selectively mixed to carry out ring-opening polymerization of the cyclocaprolactone. Wherein, the weight molar concentration of the stannous isooctylate is preferably 0.01 M, and the weight molar concentration of the cyclocaprolactone is preferably 25 M. In the present embodiment, 20 ml of xylene was added in the case where the DMF-DMA reagent was mixed, and 5 ml of xylene was added without mixing the DMF-DMA reagent to simultaneously react for 1.2 hours.

Table 1-2: The case where the tin-containing catalyst catalyzes the formation of a high molecular weight polymer by cyclocaprolactone.

As is apparent from the results of Table 1-2, by mixing the tin-containing catalyst complex formed by the tin-containing catalyst with the DMF-DMA reagent, ring-opening polymerization of 2,500-fold of cyclocaprolactone can be carried out at the same time. When the DMF-DMA reagent is not mixed, the conversion of the cyclocaprolactone is obviously increased from 23% to 76%, and the polycyclohexanolide is formed. The molecular weight can be as high as 74,000 and the molecular weight distribution is 3.7. Herein, it is confirmed that the N,N-dialkylformamidine dialkyl acetal reagent is first reacted with the tin-containing catalyst to obtain a tin-containing catalyst complex having high catalytic activity. In order to improve the catalytic efficiency of the tin-containing catalyst, the effect of rapidly synthesizing the high molecular weight polycyclocaprolactone is achieved at a low temperature of 140 degrees Celsius.

Referring to Table 2-1, it is a case where a tin-containing catalyst catalyzes the formation of a polymer of lactide, and the N,N-dialkylformamide dialkyl acetal reagent of the present embodiment is selected to be N. N-dimethylformamide dimethyl acetal (DMF-DMA); the tin-containing catalyst comprises stannous isooctylate, stannous sulfate, stannous chloride and dibutyltin oxide, and the tin-containing catalyst The weight molar concentration is preferably 0.01M. Herein, the DMF-DMA reagent is separately mixed with the tin-containing catalysts according to different ratios, and then benzyl alcohol (BnOH) is selectively added as a polymerization initiator to react with the unadded DMF-MDA. For comparison, 10 ml of toluene was added as a solvent in an environment of 100 ° C to carry out ring-opening polymerization of lactide (L-lactide, LA). Among them, the weight molar concentration of the lactide is preferably selected to be 0.5M.

Table 2-1: The case where the tin-containing catalyst catalyzes the lactide to form a polymer.

As is apparent from the results of Table 2-1, regardless of which of the selected tin-containing catalysts, the group of the DMF-DMA reagents (a1, b1, c1, and d1) were added during the ring-opening polymerization of the lactide. The conversion ratio of the lactide at the same time is compared to the group (a2, b2, c21, and d2) to which the benzyl alcohol is added as a polymerization initiator without adding the DMF-DMA reagent. Significantly improved, thereby demonstrating that the addition of the DMF-DMA reagent can greatly enhance the activity of the tin-containing catalyst itself, and at the low temperature of 100 degrees Celsius, accelerate the ring-opening polymerization of the lactide to form polylactic acid. The effect of the ester.

In addition, please refer to Table 2-2, which is a case where a tin-containing catalyst catalyzes the formation of a high molecular weight polymer by lactide. In this embodiment, stannous isooctylate is selected as a catalyst at an environment of 140 degrees Celsius. 4000 times of lactide was added, and the DMF-DMA reagent was selectively mixed to carry out ring-opening polymerization of the lactide. Wherein, the weight molar concentration of the stannous isooctylate is preferably 0.0025 M, and the weight molar concentration of the lactide is preferably 10 M. In the present embodiment, 40 ml of xylene was added in the case where the DMF-DMA reagent was mixed, and 20 ml of xylene was added without mixing the DMF-DMA reagent to simultaneously react for 2.8 hours.

Table 2-2: The case where the tin-containing catalyst catalyzes the lactide to form a high molecular weight polymer.

It is known from the results of Table 2-2 that the stannous isooctylate complex formed by mixing the stannous isooctylate with the DMF-DMA reagent can perform ring-opening polymerization on 4000 times of lactide. At the time, when the DMF-DMA reagent is not mixed with the addition of the tin-containing catalyst, the lactide-based polymerization catalyzed by the stannous isooctylate complex is agglomerated, and the polylactic acid is formed. The molecular weight after the ester can be as high as 405,000 and the molecular weight distribution is 2.87. Herein, it is confirmed that the N,N-dialkylformamide dialkyl acetal reagent is first reacted with the tin-containing catalyst to obtain a tin-containing catalyst complex having high catalytic activity. The catalytic efficiency of the tin-containing catalyst is improved, and the high-molecular-weight polylactide is rapidly synthesized at a low temperature of 140 degrees Celsius.

The method for the polyesterification reaction of the tin-containing catalyst of the present invention is capable of improving the catalytic activity of the tin-containing catalyst to improve the catalytic efficiency of the tin-containing catalyst in the polyesterification reaction, so as to achieve the ester compound rapidly The effect of polymerization.

The method for the polyesterification reaction of the tin-containing catalyst of the invention is capable of maintaining the low sensitivity of the tin-containing catalyst to air to ensure the catalytic effect of the tin-containing catalyst in the polyesterification reaction, and to form a high molecular weight ester. The efficacy of polymers.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

[this invention]

S1. . . Mixing step

S2. . . Aggregation step

Figure 1: Flow chart of the operation of the present invention.

Figure 2a: Spectral analysis of the invention.

2b~2c: Schematic diagram of the chemical structure of the present invention.

Figure 3: Reaction Scheme 1 of the chemical structure of the present invention.

Figure 4: The chemical structure of the present invention is further.

Claims (9)

A method for using a tin-containing catalyst for a polyesterification reaction, comprising: a mixing step of mixing a N,N-dialkylformamidine dialkyl acetal reagent with a tin-containing catalyst to make the N, N Transferring the alkoxy group bonded by the dialkylformamidine dialkyl acetal reagent to the tin-containing catalyst to obtain a tin-containing catalyst complex; and a polymerization step by which the tin-containing catalyst is coupled Catalyzing a monoester compound to undergo ring-opening polymerization to form a polyester polymer; wherein the N,N dialkylformamidine dialkyl acetal reagent is a compound represented by Chemical Formula 1 And R in the chemical formula 1 is an alkyl group. (RO) ₂ CHNR ₂ [Chemical Formula 1] A method for the polyesterification reaction according to the tin-containing catalyst of claim 1, wherein the N,N-dialkylformamidine dialkyl acetal reagent is N,N-dimethylmethyl Indole dimethyl acetal or N,N-dimethylformamide diethyl acetal. A method of using a tin-containing catalyst according to claim 1 or 2 for a polyesterification reaction, wherein the tin-containing catalyst is mixed with the N,N-dialkylformamidine dialkyl acetal reagent The ratio is 1:1. A method for the polyesterification reaction according to the tin-containing catalyst according to claim 1 or 2, wherein the tin-containing catalyst is stannous isooctanoate, stannous sulfate, stannous chloride or dibutyltin oxide. . A method of using a tin-containing catalyst according to claim 1 or 2 for a polyesterification reaction, wherein the tin-containing catalyst has a molar concentration of 0.0025 to 0.08 M. The method for the polyesterification reaction according to the tin-containing catalyst according to claim 1 or 2, wherein the tin-containing catalyst complex catalyzes the reaction temperature of the ester compound to be 100 ° C. 140 degrees. A method for the polyesterification reaction according to the tin-containing catalyst according to claim 1 or 2, wherein the ester compound is cyclocaprolactone, and the molar concentration of the cyclohexanolide is 2 ~25M. A method for the polyesterification reaction according to the tin-containing catalyst according to claim 1 or 2, wherein the ester compound is lactide, and the lactide has a weight molar concentration of 0.5 to 10 M. . According to the method for the polyesterification reaction of the tin-containing catalyst according to claim 1 or 2, when the tin-containing catalyst complex is mixed with the ester compound, a solvent is added, The solvent was 10 ml of toluene.