CN114621246B - Method for preparing isoidide diacetate - Google Patents

Abstract

The application discloses a method for preparing isoidide diacetate. The method for preparing isoidide diacetate comprises the steps of contacting raw materials containing biological base sugar alcohol substances and an acetylation reagent with a solid acid catalyst, and carrying out one-pot reaction to obtain isoidide diacetate; wherein the sugar alcohol substance comprises at least one of sorbitol and isosorbide. The synthesis method has the advantages of easily obtained raw materials, no need of hydrogen and hydrogenation catalyst, mild reaction conditions, simple operation, low requirements on equipment, easy separation of products and recycling of the catalyst.

Description

A kind of method for preparing isoidide diacetate

technical field

The application relates to a method for preparing isoidide diacetate, which belongs to the technical field of catalytic synthesis.

Background technique

Isohexitol, mainly including isosorbide, isomannide and isoidide, as bio-based functional diols, is an important class of bio-based platform molecules, which can be obtained from the dehydration of sugar-derived hexitols. Isohexitol can be applied to green solvents, medicines, surfactants, plasticizers, fuel additives and polymers by itself or further chemical modification due to its unique dihydroxy functional group, rigid structure, chiral center and non-toxicity. and other fields, has very broad application prospects. More importantly, isohexitol, as a bio-based polymer monomer, has great potential to replace traditional toxic petroleum-based monomers, and is used to construct polyesters, polyethers, polyurethanes, polycarbonates, etc. with excellent properties such as high glass transition temperature. polymeric material.

Affected by the configuration of dihydroxyl groups in the molecular structure of isohexitol, the inner hydroxyl group presents greater steric hindrance than the outer hydroxyl group, resulting in lower reactivity. Thus, the asymmetric configuration of the two hydroxyl groups in the isosorbide molecule leads to its different reactivity and limited polymer crystallinity. Similarly, although the isomannide molecule has two symmetrical internal hydroxyl groups, it is restricted by steric hindrance, resulting in low reactivity and low linearity of the polymerized product, which is not conducive to the progress of the polymerization reaction. Compared with the above two isohexitols, isoidide has two symmetrical external hydroxyl groups. The symmetry and high reactivity of its hydroxyl structure make isoidide more suitable as a polymerizable monomer, thereby constructing a polymer with high crystallinity. Polymer materials with excellent properties.

Although isoidide can be obtained by continuous dehydration of idose hydrogenation product iditol, like isosorbide through the secondary dehydration of glucose hydrogenation product sorbitol, however, idose is rarely found in nature and cannot It is obtained in large quantities from plant sources, so the route of obtaining iditol by catalytic hydrogenation of idose, followed by continuous dehydration to produce isoidide is not suitable for large-scale production. It has been reported in the literature that iditol can be obtained by catalyzed isomerization of sorbitol under high temperature and high pressure hydrogen conditions through a nickel catalyst. big. In summary, in view of the difficulty in obtaining raw materials of idose and iditol, the synthetic route of producing isoidide through catalytic dehydration of iditol is not suitable for the large-scale production of isoidide.

Considering that the raw material iditol is difficult to obtain, the way of synthesizing isoidide alcohol through epimerization using easily available isosorbide as raw material has attracted attention. The current literature involves isomerization of isosorbide into isoidide requires hydrogen and hydrogenation catalysts. For example, the literature reports that under the harsh conditions of high temperature of 220-240°C and high pressure of 10.3MPa hydrogen, the isomerization of isosorbide is catalyzed by diatomaceous earth-supported metal Ni as a catalyst, and the reaction reaches equilibrium in 2 hours. The yield of isoidide is was 57%. As another example, it was reported that the use of Ru/C catalyst can catalyze the epimerization reaction of isosorbide in alkaline aqueous solution (PH=8) at 220°C and 4MPa hydrogen gas to obtain isoidide. The rate is 55%. However, high-temperature, high-pressure hydrogen and hydrogenation catalysts are necessary for the isomerization of isosorbide to isoidide, and the result is a mixture of isomers of isohexitol, which requires high-temperature, high-vacuum, high-energy distillation to purify isoidide. Deritol is easy to carbonize isohexitol, which affects the yield and quality of the product.

The high boiling point of isoidide stems from the strong polarity and intermolecular hydrogen bonds caused by dihydroxyl groups. Therefore, after the two free hydroxyl groups are modified by acetylation to form isoidide diacetate, the boiling point is significantly reduced. Thereby reducing the energy consumption of separation. Not only that, the dihydroxy functional group is the main cause of high-temperature carbonization of isoidide, and it is expected to inhibit the side reaction of polymerization after being modified by esterification. In addition, the esterification reaction is a reversible reaction, and isoidide diacetate is easy to form isoidide through hydrolysis or alcoholysis. Based on this, replacing isoidide with isoidide diacetate as the target product has significant advantages in separation and purification. At present, there is no report on the direct preparation of isoidide diacetate from readily available sorbitol or isosorbide.

In summary, the existing isoidide isomerization technology for producing isoidide has harsh reaction conditions (high temperature and high pressure), the use of hydrogen and hydrogenation catalysts, high equipment requirements, high energy consumption for isoidide separation, and high temperature distillation process. Substrate carbonization and other problems are prone to occur in the process.

Contents of the invention

The object of the present invention aims at the high temperature and high pressure harsh reaction conditions existing in the existing isoidide alcohol preparation technology, using hydrogen and hydrogenation catalyst, high temperature, high vacuum and high energy consumption separation operation and the problem of easy carbonization in the separation process, to provide a solid acid A new method for preparing isoidide diacetate by catalyzing sorbitol or isosorbide in one pot. The method has the advantages of easy-to-obtain raw materials, no need for hydrogen and hydrogenation catalyst, mild reaction conditions, simple operation, low equipment requirements, easy separation of products, recyclable and reusable catalyst, and the like.

According to one aspect of the present application, a method for preparing isoidide diacetate is provided.

A method for preparing isoidide diacetate, comprising contacting raw materials containing bio-based sugar alcohols and acetylation reagents with a solid acid catalyst, and performing a one-pot reaction to obtain isoidide diacetate;

Wherein, the sugar alcohols include at least one of sorbitol and isosorbide.

Optionally, the solid acid catalyst includes at least one of strongly acidic cation exchange resins, hydrogen-type zeolite molecular sieves, Keggin-type heteropolyacids, and solid superacids.

Optionally, the strongly acidic cation exchange resin is selected from at least one of Amberlyst-15, Amberlyst-35, Amberlyst-70 and Nafion-H.

Optionally, the hydrogen-type zeolite molecules are selected from at least one of H-ZSM-5, H-Beta, and H-Y.

Optionally, the Keggin-type heteropolyacid is selected from at least one of phosphotungstic heteropolyacid and silicotungstic heteropolyacid.

Optionally, the solid superacid is selected from at least one of sulfated zirconia and sulfated alumina.

Optionally, the acetylating agent is selected from at least one of acetic acid, acetic anhydride, and acetyl chloride.

Optionally, an aprotic solvent is also added to the raw material.

Optionally, the aprotic solvent is selected from at least one of sulfolane, ethyl acetate, butyl acetate, cyclohexane, and toluene.

Optionally, the mass ratio of the solid acid catalyst to the bio-based sugar alcohol is 0.005:1˜1:1.

Preferably, the mass ratio of the solid acid catalyst to the bio-based sugar alcohol is 0.01:1˜0.7:1.

Optionally, the mass ratio of the solid acid catalyst to the bio-based sugar alcohols is independently selected from 0.005:1, 0.01:1, 0.03:1, 0.05:1, 0.07:1, 0.1:1, 0.2:1 , 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1 or any value in the range between them.

Optionally, the molar ratio of the acetylation reagent to the bio-based sugar alcohol is 2:1˜150:1.

Preferably, the molar ratio of the acetylation reagent to the bio-based sugar alcohol is 4:1˜100:1.

Optionally, the molar ratio of the acetylating agent to the bio-based sugar alcohol is independently selected from 2:1, 4:1, 7:1, 10:1, 20:1, 40:1, 50:1 , 70:1, 90:1, 100:1, 120:1, 140:1, 150:1, or any value in between.

Optionally, the molar ratio of the aprotic solvent to the bio-based sugar alcohol is 0-100:1.

Preferably, the molar ratio of the aprotic solvent to the bio-based sugar alcohol is 0-70:1.

Optionally, the molar ratio of the aprotic solvent to the bio-based sugar alcohol is independently selected from 1:1, 5:1, 8:1, 10:1, 15:1, 20:1, 30:1 , 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1 or any value in the range between the two.

In this application, the aprotic solvent is added selectively and is not necessary.

Optionally, the reaction temperature is 130-200°C; the reaction time is 0.5-12h.

Preferably, the reaction temperature is 150-200° C., and the reaction time is 1-10 h.

Optionally, the temperature of the reaction is independently selected from any value among 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or any range between them.

Optionally, the reaction time is independently selected from any value in 0.5h, 1h, 2h, 4h, 5h, 6h, 8h, 10h, 12h or any range between the two.

There is no special requirement on the pressure of the reaction, so it is not strictly limited, and the reaction can be carried out under sealed self-pressurized conditions.

In view of the advantage that the boiling point of isoidide diacetate and carbonization activity are significantly lower than that of isoidide, this application explores a new strategy and realizes the one-pot preparation of isoidide from sorbitol or isosorbide under mild conditions. Alcohol diacetates, avoiding the use of hydrogen and hydrogenation catalysts, are of great importance.

The beneficial effect that this application can produce comprises:

The method for preparing isoidide diacetate provided by the application is as a method for preparing isoidide diacetate directly in one pot with sugar alcohols (such as sorbitol, isosorbide) as raw materials. A new environment-friendly synthetic strategy, with the use of bio-based sorbitol or isosorbide from a wide range of sources as raw materials, through the catalytic conversion of environmentally friendly solid acid, isoidide diacetate can be obtained in one pot. The method does not require hydrogen and a hydrogenation catalyst, has mild reaction conditions, is simple to operate, and has low requirements for equipment; taking isoidide as the target product can effectively reduce energy consumption and is not easily carbonized; the solid acid catalyst can be recycled and reused.

Detailed ways

The present application is described in detail below in conjunction with the examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and catalysts in the examples of the present application were purchased through commercial channels. Unless otherwise specified, the test methods are conventional methods, and the instrument settings are all the settings recommended by the manufacturer.

Isoidide diacetate yield is calculated with molar yield in the embodiment of the application:

Yield of isoidide diacetate = molar amount of isoidide diacetate generated/ molar amount of sorbitol or isosorbide input × 100%

Example 1

Put sorbitol, acetic acid and solid acid catalyst H-ZSM-5 molecular sieve (SiO ₂ /Al ₂ O ₃ =150) into the reaction kettle, replace with nitrogen, seal the reactor, and react with magnetic stirring at 180°C for 5 hours. Wherein, the molar ratio of acetic acid to sorbitol is 70:1, and the mass ratio of H-ZSM-5 to sorbitol is 0.3:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of obtained isoidide diacetate was 45mol%.

Example 2

Put sorbitol, acetic anhydride, ethyl acetate and solid acid catalyst Amberlyst-15 into the reaction kettle, replace with nitrogen, seal the reactor, and react with magnetic stirring at 130°C for 10h. Wherein, the molar ratio of acetic anhydride to sorbitol is 10:1, the molar ratio of ethyl acetate to sorbitol is 10:1, and the mass ratio of Amberlyst-15 to sorbitol is 0.7:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the obtained isoidide diacetate yield was 42mol%.

Example 3

Sorbitol, acetic acid, toluene and solid acid catalyst H-Beta molecular sieve (SiO ₂ /Al ₂ O ₃ =100) were put into the reaction kettle, replaced with nitrogen, the reactor was sealed, and the reaction was performed with magnetic stirring at 190°C for 4 hours. Wherein, the molar ratio of acetic acid to sorbitol is 90:1, the molar ratio of toluene to sorbitol is 30:1, and the mass ratio of H-Beta to sorbitol is 0.2:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of obtained isoidide diacetate was 47mol%.

Example 4

Put sorbitol, acetic acid and solid acid catalyst phosphotungstic heteropolyacid into the reaction kettle, replace with nitrogen, seal the reactor, and react with magnetic stirring at 200°C for 2h. Wherein, the molar ratio of acetic acid and sorbitol is 4:1, and the mass ratio of phosphotungstic heteropolyacid and sorbitol is 0.1:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of isoidide diacetate was 41mol%.

Example 5

Put isosorbide, acetic acid, butyl acetate and solid acid catalyst Nafion-H into the reactor, replace with nitrogen, seal the reactor, and react with magnetic stirring at 200°C for 2h. Wherein, the molar ratio of acetic acid to isosorbide is 40:1, the molar ratio of butyl acetate to isosorbide is 50:1, and the mass ratio of Nafion-H to isosorbide is 0.05:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of obtained isoidide diacetate was 48mol%.

Example 6

Put sorbitol, acetic acid, sulfolane and solid acid catalyst sulfated zirconia into the reaction kettle, replace with nitrogen, seal the reactor, and react with magnetic stirring at 200°C for 2h. Wherein, the molar ratio of acetic acid to sorbitol is 120:1, the molar ratio of sulfolane to sorbitol is 70:1, and the mass ratio of sulfated zirconia to sorbitol is 0.4:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of obtained isoidide diacetate was 46mol%.

Example 7

Put isosorbide, acetic acid, cyclohexane and solid acid catalyst silicotungstic heteropolyacid into the reactor, replace with nitrogen, seal the reactor, and react with magnetic stirring at 170°C for 4h. Wherein, the molar ratio of acetic acid to isosorbide is 20:1, the molar ratio of cyclohexane to isosorbide is 5:1, and the mass ratio of silicotungstic heteropolyacid to isosorbide is 0.4:1. After the reaction was completed, the esterification product was quantitatively analyzed by gas chromatography internal standard method, expressed in mole percent (mol%), and the yield of obtained isoidide diacetate was 47mol%.

The above are only a few embodiments of the application, and do not limit the application in any form. Although the application is disclosed as above with preferred embodiments, it is not intended to limit the application. Any skilled person familiar with this field, Without departing from the scope of the technical solution of the present application, any changes or modifications made using the technical content disclosed above are equivalent to equivalent implementation cases, and all belong to the scope of the technical solution.

Claims (5)

1. A method for preparing isoidide diacetate is characterized in that raw materials containing biological glycosyl alcohol substances and an acetylating reagent are contacted with a solid acid catalyst and reacted in a one-pot way to obtain isoidide diacetate;

wherein the biological sugar alcohol is at least one of sorbitol and isosorbide;

the solid acid catalyst is at least one selected from strong acid cation exchange resin, hydrogen type zeolite molecular sieve, keggin type heteropolyacid and solid super acid;

the strong acid cation exchange resin is selected from at least one of Amberlyst-15, amberlyst-35, amberlyst-70 and Nafion-H;

the hydrogen type zeolite molecular sieve is selected from at least one of H-ZSM-5, H-Beta and H-Y;

the Keggin type heteropolyacid is selected from at least one of phosphotungstic heteropolyacid and silicotungstic heteropolyacid;

the solid super acid is at least one selected from sulfated zirconia and sulfated alumina;

the acetylating agent is at least one of acetic acid, acetic anhydride and acetyl chloride;

adding an aprotic solvent to the feedstock;

the aprotic solvent is selected from at least one of sulfolane, ethyl acetate, butyl acetate, cyclohexane and toluene;

the mass ratio of the solid acid catalyst to the bio-based sugar alcohol substance is 0.01:1-0.7:1;

the mol ratio of the acetylation reagent to the biological glycosyl sugar alcohol substance is 2:1-150:1;

the reaction temperature is 130-200 ℃; the reaction time is 0.5-12 h.

2. The method of claim 1, wherein the molar ratio of the acetylating agent to the biosyl sugar alcohol is 4:1 to 100:1.

3. The method of claim 1, wherein the molar ratio of the aprotic solvent to the biobased sugar alcohol is 0-100:1.

4. The method of claim 1, wherein the molar ratio of the aprotic solvent to the biobased sugar alcohol is 0-70:1.

5. The method according to claim 1, wherein the reaction temperature is 150-200 ℃ and the reaction time is 1-10 hours.