CN115073324A - A kind of method utilizing homogeneous catalysis to prepare pentamethylene dicarbamate - Google Patents

Abstract

The invention provides a method for preparing pentamethylene dicarbamate by utilizing a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and a homogeneous catalyst to carry out an oxo synthesis reaction to obtain pentamethylene dicarbamic acid ester; wherein the homogeneous catalyst comprises organic acid and/or water. The method provided by the invention improves the catalytic efficiency and the yield of the target product, simplifies the technological process, reduces the preparation cost, and is suitable for industrial production.

Description

A kind of method utilizing homogeneous catalysis to prepare pentamethylene dicarbamate

technical field

The invention belongs to the technical field of chemical synthesis, and relates to a method for preparing pentamethylene dicarbamate, in particular to a method for preparing pentamethylene dicarbamate by utilizing a homogeneous catalyst.

Background technique

Pentamethylene dicarbamate (PDC) is a kind of bio-based carbamate, and its synthetic raw material, pentamethylene diamine (PDA), is obtained from biomass fermentation, so PDC has a good application prospect in the future market. PDC can be used to synthesize isocyanate, polyurethane and other substances, and be used in industrial fields such as automobiles and wind power, as well as in daily necessities such as artificial leather and leather shoes. With the large-scale production of PDA biological method, more and more researchers focus on the synthesis of PDC. In the synthesis process of PDC, the role of catalyst is very important, but there are few reports at home and abroad about the synthesis of PDC.

CN 108689884A discloses a preparation method of 1,5-pentamethylene diisocyanate, comprising the following steps: (1) mixing 1,5-pentamethylenediamine conversion liquid and extraction solvent to extract 1,5-pentamethylenediamine, and then extracting 1,5-pentamethylenediamine The liquid is dehydrated to obtain a mixture of 1,5-pentamethylenediamine and extraction solvent; (2) catalyst and urea are added to the mixture of 1,5-pentamethylenediamine and extraction solvent, and an appropriate amount of extraction solvent is added to form a reaction system , 1,5-pentanediamine is carbamate and the excess extraction solvent in the reaction system is recovered by distillation under reduced pressure to obtain PDU; (3) PDU is mixed with heat carrier and catalyst to carry out thermal cracking reaction, and the separation is obtained Extraction solvent and PDI. The preparation method adopts zirconium acetate to catalyze the carbamate of urea and PDA extract to synthesize butyl carbamate. However, polyurea by-products are easily generated during the carbonylation process, which not only reduces the yield in practical applications, but also reduces the yield. Block the line.

CN 113603613A discloses a method for catalyzing synthesis of pentamethylene dicarbamate. Pentamethylene diamine and carbonylation agent are added into a solvent to dissolve, and the catalytic synthesis reaction is carried out through titanium dioxide catalyst. Since the catalytic synthesis method adopts a solid-phase catalyst, the efficiency of the catalytic reaction is limited, and the catalyst needs to be separated after the reaction is completed, and the technological process is relatively complicated.

It can be seen that how to provide a preparation method of pentamethylene dicarbamate, further improve the catalytic efficiency and the yield of the target product, at the same time simplify the process flow, reduce the preparation cost, and be suitable for industrial production, which has become a problem for those skilled in the art. An urgent problem to be solved.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the object of the present invention is to provide a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method improves the catalytic efficiency and the yield of the target product, and simplifies the process flow simultaneously, The preparation cost is reduced, and it is suitable for industrial production.

For this purpose, the present invention adopts the following technical solutions:

The invention provides a method for preparing pentamethylene dicarbamate by homogeneous catalysis. The method comprises: mixing pentamethylene diamine, dimethyl carbonate and a homogeneous catalyst to carry out an oxo synthesis reaction to obtain the pentamethylene dicarbamate.

Wherein, the homogeneous catalyst includes organic acid and/or water.

In the present invention, organic acid and/or water are selected as homogeneous catalysts in the preparation process of pentamethylene dicarbamate. Compared with traditional heterogeneous catalysis reactions, the catalytic efficiency of such homogeneous catalysis reactions is higher, and at the same time The yield of the target product can reach more than 90%, and when only water is used as a homogeneous catalyst, the pentamethylene dicarbamate can be automatically precipitated at room temperature, which reduces the separation steps, thereby simplifying the process flow and reducing the preparation time. cost, suitable for industrial production.

Preferably, the organic acid includes any one or a combination of at least two of acetic acid, propionic acid, malonic acid, butyric acid, glycine, alanine or lysine, a typical but non-limiting combination includes acetic acid Combination with Propionic Acid, Combination of Propionic Acid and Malonic Acid, Combination of Malonic Acid and Butyric Acid, Combination of Butyric Acid and Glycine, Combination of Glycine and Alanine, Combination of Alanine and Lysine, Acetic Acid , a combination of propionic acid and malonic acid, a combination of propionic acid, malonic acid and butyric acid, a combination of malonic acid, butyric acid and glycine, a combination of butyric acid, glycine and alanine, a combination of glycine, alanine and glycine A combination of lysine, acetic acid, propionic acid, a combination of malonic acid and butyric acid, a combination of propionic acid, malonic acid, butyric acid and glycine, a combination of malonic acid, butyric acid, glycine and alanine, or A combination of butyric acid, glycine, alanine and lysine.

Preferably, the mixing molar ratio of the pentamethylenediamine, dimethyl carbonate and the homogeneous catalyst is 1:(2-10):(2-12), for example, it can be 1:2:2, 1:2:4 , 1:2:6, 1:2:8, 1:2:10, 1:2:12, 1:5:2, 1:5:4, 1:5:6, 1:5:8, 1 :5:10, 1:5:12, 1:10:2, 1:10:4, 1:10:6, 1:10:8, 1:10:10 or 1:10:12, more preferably 1:(2-5):(2-6), but not limited to the recited values, and other unrecited values within the range of values are also applicable.

Preferably, the homogeneous catalyst includes organic acid and water.

Preferably, the mixed molar ratio of the organic acid and water is 1:(2-4), for example, it can be 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1 : 3.2, 1:3.4, 1:3.6, 1:3.8 or 1:4, but not limited to the recited values, other unrecited values within the range of values are also applicable.

In the present invention, a mixed solution of organic acid and water is preferred as a homogeneous catalyst, and the mixed molar ratio is strictly limited within a reasonable range, which can further improve the catalytic efficiency and the yield of the target product while reducing the catalyst cost as much as possible, thereby improving economic benefits. , which is conducive to industrial production.

Preferably, the temperature of the oxo synthesis reaction is 50-120°C, such as 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C, more preferably 50-100°C °C, but is not limited to the recited values, and other unrecited values within the numerical range are equally applicable.

In the present invention, the temperature of the oxo synthesis reaction needs to be controlled within a reasonable range. When the temperature is lower than 50 °C, the catalytic efficiency is too low, and the yield of the target product is less than 90%; when the temperature is higher than 120 °C, the side reactions increase, which will also reduce the yield of the target product, and at the same time, the energy consumption is increased, and the Conducive to saving the preparation cost.

Preferably, the time of the oxo synthesis reaction is 0.5-10h, such as 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, more preferably 2-8h, but Not limited to the recited values, other non-recited values within the range of values apply equally.

Preferably, the oxo reaction is also accompanied by stirring.

Preferably, the stirring speed is 100-1000 rpm, for example, it can be 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm or 1000 rpm, but not limited to the listed values, other values within the range The same applies to non-recited values.

As a preferred technical solution of the present invention, the method includes:

According to the molar ratio of 1:(2-5):(2-6), pentamethylenediamine, dimethyl carbonate and homogeneous catalyst were mixed, and the oxo synthesis reaction was carried out at 50-100 ° C for 2-8 h, accompanied by Stirring at a rate of 100-1000 rpm to obtain pentamethylene dicarbamate; wherein, the homogeneous catalyst comprises an organic acid and water with a mixed molar ratio of 1:(2-4), and the organic acid comprises acetic acid, propylene Any one or a combination of at least two of acid, malonic acid, butyric acid, glycine, alanine, or lysine.

The numerical range described in the present invention not only includes the above-mentioned exemplified point values, but also includes any point value between the above-mentioned numerical ranges that are not exemplified. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list them. The specific point value included in the above range.

Compared with the prior art, the beneficial effects of the present invention are:

The present invention selects organic acid and/or water as the homogeneous catalyst in the preparation process of pentamethylene dicarbamate. Compared with the traditional heterogeneous catalysis reaction, the catalytic efficiency of this type of homogeneous catalysis reaction is higher, and the target The yield of the product can reach more than 90%, and when only water is used as the homogeneous catalyst, the pentamethylene dicarbamate can be automatically precipitated at normal temperature, and the separation steps are reduced, thereby simplifying the technological process and reducing the preparation cost. , suitable for industrial production.

Detailed ways

The technical solutions of the present invention are further described below through specific embodiments.

Example 1

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and a homogeneous catalyst in a molar ratio of 1:3:4, and at 80 The oxo synthesis reaction was carried out at ℃ for 5 h, accompanied by stirring at a rate of 500 rpm, to obtain pentamethylene dicarbamate; wherein, the homogeneous catalyst was acetic acid and water with a mixed molar ratio of 1:3.

Example 2

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and a homogeneous catalyst in a molar ratio of 1:5:6, and at 60 The oxo synthesis reaction was carried out at ℃ for 8 h, and accompanied by stirring at a rate of 300 rpm, to obtain pentamethylene dicarbamate; wherein, the homogeneous catalyst was propionic acid and water with a mixed molar ratio of 1:2.

Example 3

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and a homogeneous catalyst in a molar ratio of 1:2:2, and at 100 The oxo synthesis reaction is carried out at ℃ for 0.5 h, accompanied by stirring at a rate of 800 rpm, to obtain pentamethylene dicarbamate; wherein, the homogeneous catalyst is a mixture of butyric acid and water with a molar ratio of 1:4.

Example 4

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and glycine in a molar ratio of 1:10:2, and heating at 50° C. The oxo reaction was carried out for 10 h with stirring at 100 rpm to give the pentamethylene dicarbamate.

Example 5

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst, the method comprising: mixing pentamethylene diamine, dimethyl carbonate and water in a molar ratio of 1:2:12, and heating at 120° C. The oxo reaction was carried out for 2 h with stirring at 1000 rpm to give pentamethylene dicarbamate.

Example 6

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst. In the method, except for changing the molar ratio of pentamethylene diamine, dimethyl carbonate and the homogeneous catalyst to 1:1:1, the remaining The conditions are the same as those in Example 1, so they are not repeated here.

Example 7

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst. In the method, except for changing the mixed molar ratio of pentamethylene diamine, dimethyl carbonate and the homogeneous catalyst to 1:12:14, the remaining The conditions are the same as those in Example 1, so they are not repeated here.

Example 8

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst. The method is the same as that in Example 1 except that the molar ratio of acetic acid and water in the homogeneous catalyst is changed to 1:1. , so it is not repeated here.

Example 9

This embodiment provides a method for preparing pentamethylene dicarbamate using a homogeneous catalyst. The method is the same as that in Example 1 except that the molar ratio of acetic acid and water in the homogeneous catalyst is changed to 1:5. , so it is not repeated here.

Example 10

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst, except that the temperature of the oxo synthesis reaction is reduced to 40°C, the other conditions are the same as those in embodiment 1, so it is omitted here. Repeat.

Example 11

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst, except that the temperature of the oxo reaction is raised to 130° C., the other conditions are the same as those in embodiment 1, so it is not repeated here. Repeat.

Example 12

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst. Except that the time of the oxo synthesis reaction is shortened to 0.3h, the other conditions are the same as those in the embodiment 1, so it is omitted here. Repeat.

Example 13

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst. Except that the time of the oxo synthesis reaction is extended to 12h, the other conditions are the same as those in Embodiment 1, so they are not repeated here. .

Example 14

This embodiment provides a method for preparing pentamethylene dicarbamate by using a homogeneous catalyst. Except that the method does not carry out stirring operation during the oxo synthesis reaction, other conditions are the same as those in embodiment 1, so it is omitted here. Repeat.

Comparative Example 1

This comparative example provides a method for preparing pentamethylene dicarbamate, the method adopts the titanium dioxide prepared in Example 1 in CN113603613A as a catalyst, and the specific method is: mixing pentamethylene diamine and carbonic acid in a molar ratio of 1:3:4 The oxo-synthesis reaction of dimethyl ester and titanium dioxide was carried out at 80° C. for 6 h with stirring at a rate of 300 rpm to obtain pentamethylene dicarbamate.

Utilize gas chromatographic analysis technology to carry out compositional analysis to the products obtained from Examples 1-14 and Comparative Example 1, and the specific analysis conditions are as follows:

Chromatographic column model RTX-5; the column temperature is initially 50°C, retained for 1min, raised to 150°C at 20°C/min, retained for 1min, then raised to 220°C at 20°C/min, and kept at 220°C for 12min; the control mode is pressure control, Pressure 110kPa, purge flow 3mL/min, split ratio 25; gasification temperature 250℃.

The composition analysis results of the products obtained in Examples 1-14 and Comparative Example 1 are shown in Table 1 below.

Table 1

group PDA conversion rate (%) PDC yield (%) Example 1 98 95 Example 2 99 97 Example 3 94 90 Example 4 99 93 Example 5 98 91 Example 6 96 85 Example 7 99 87 Example 8 99 93 Example 9 99 88 Example 10 93 85 Example 11 95 88 Example 12 90 80 Example 13 95 90 Example 14 92 86 Comparative Example 1 55 13

It can be seen from Table 1 that the efficient synthesis of PDC can be achieved by using water and/or organic acids as homogeneous catalysts. From the comparison of Example 1, Example 6 and Example 7, it can be known that the ratio of raw materials and catalysts has a significant impact on the reaction yield. When the amount of dimethyl carbonate and the catalyst is too small, the reactants are reduced and the reaction is not sufficient; when the amount of dimethyl carbonate is too much, the PDC yield also decreases significantly. From the comparison of Example 1, Example 8 and Example 9, it can be known that the mixing ratio of water and organic acid has a certain influence on the yield of pentamethylene dicarbamate. With the increase of acid ratio, the yield of PDC also increased; when the amount of water was more, the yield of PDC decreased. From the comparison of Example 1, Example 10 and Example 11, it can be known that the reaction temperature exceeding the preferred range has a certain adverse effect on the yield of pentamethylene dicarbamate. If the temperature is too high, a part of by-products will be formed; if the temperature is too low, the conversion rate of PDA will decrease. From the comparison of Example 1, Example 12 and Example 13, it can be known that the reaction time is too short, and the reaction of pentamethylenediamine and dimethyl carbonate is insufficient; yield. From the comparison between Example 1 and Example 14, it can be seen that stirring has a certain promoting effect on the reaction, which can promote mass transfer and heat transfer, thereby improving the yield of PDC. It can be seen from Example 1 and Comparative Example 1 that when TiO ₂ is used as a catalyst, the catalytic effect is significantly reduced, indicating that TiO ₂ is not suitable for catalyzing the reaction of dimethyl carbonate and pentamethylene diamine carbonylation under mild conditions.

It can be seen that the present invention selects organic acids and/or water as homogeneous catalysts in the preparation process of pentamethylene dicarbamate. Compared with traditional heterogeneous catalysis reactions, the catalytic efficiency of such homogeneous catalysis reactions is higher. At the same time, the yield of the target product can reach more than 90%, and when only water is used as the homogeneous catalyst, the pentamethylene dicarbamate can be automatically precipitated at room temperature, which reduces the separation steps and simplifies the technological process. The preparation cost is reduced, and it is suitable for industrial production.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in further detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A process for preparing pentanedicarbamates using a homogeneous catalyst, the process comprising: mixing pentanediamine, dimethyl carbonate and a homogeneous catalyst to carry out carbonylation synthesis reaction to obtain pentanedicarbamate;

wherein the homogeneous catalyst comprises an organic acid and/or water.

2. The method of claim 1, wherein the organic acid comprises any one of acetic acid, propionic acid, malonic acid, butyric acid, glycine, alanine, or lysine, or a combination of at least two thereof.

3. The method of claim 1 or 2, wherein the mixing molar ratio of the pentamethylene diamine, the dimethyl carbonate and the homogeneous catalyst is 1 (2-10) to (2-12).

4. The method of claim 3, wherein the mixing molar ratio of the pentamethylene diamine, the dimethyl carbonate and the homogeneous catalyst is 1 (2-5) to (2-6).

5. The process of any of claims 1-4, wherein the homogeneous catalyst comprises an organic acid and water.

6. The method according to claim 5, wherein the mixing molar ratio of the organic acid to the water is 1 (2-4).

7. A process according to any one of claims 1 to 6, wherein the carbonylation synthesis reaction is carried out at a temperature of from 50 ℃ to 120 ℃, more preferably from 50 ℃ to 100 ℃.

8. The process according to any one of claims 1 to 7, wherein the carbonylation synthesis reaction is carried out for a period of time of 0.5 to 10 hours, more preferably for a period of time of 2 to 8 hours.

9. The process of any one of claims 1 to 8, wherein the oxo reaction is accompanied by stirring;

preferably, the rate of agitation is 100-.

10. The method according to any one of claims 1-9, characterized in that the method comprises: mixing pentamethylene diamine, dimethyl carbonate and homogeneous catalyst in the molar ratio of 1 to (2-5) to obtain pentamethylene dicarbamate through carbonylation reaction at 50-100 deg.c for 2-8 hr while stirring at the speed of 100-1000 rpm; the homogeneous catalyst comprises organic acid and water with the mixing molar ratio of 1 (2-4), and the organic acid comprises any one or combination of at least two of acetic acid, propionic acid, malonic acid, butyric acid, glycine, alanine or lysine.