A method for preparing 1,4-anhydroerythritol ketal compound

Abstract

The present application discloses a method for preparing a 1,4-dehydrated erythritol ketal compound, the method comprising: using bio-based erythritol as a reaction raw material, in the presence of a fatty ketone reagent, reacting to generate 1,4-dehydrated erythritol ketal through solid acid catalysis. The present invention adopts a one-pot one-step method, using bio-based erythritol as a reaction raw material, in the presence of a fatty ketone reagent, 1,4-dehydrated erythritol ketal is generated through solid acid catalysis. The yield of the obtained product is more than 80%, the reaction process is short, the operation is simple, the reaction conditions are mild, the product is easy to separate, and the catalyst can be recycled and reused.

Description

Technical Field

[0001] The present application relates to a novel method for preparing 1,4-anhydroerythritol ketal from bio-based erythritol in one step, and belongs to the field of chemistry and chemical engineering. Background Art

[0002] Erythritol is a natural four-carbon sugar alcohol widely found in nature and is produced industrially by sugar fermentation. The market application structure of erythritol is relatively simple, and it is mainly used as a food sweetener. Therefore, the synthesis of downstream derivatives of erythritol is of great significance for the expansion of the application field of erythritol. The tetraol structure inherent in the erythritol molecule can undergo intramolecular dehydration reaction and further ketalization reaction to generate 1,4-anhydroerythritol ketal product under acid catalysis. Ketal, as an important type of chemical product, has a wide range of uses in chemical intermediates, pharmaceutical intermediates, functional protective agents, solvents, fuel additives and polymers. In addition, ketal has an ether-like structure, can exist stably under alkaline conditions, and has a special aroma that is superior to the parent ketone, and can be used as a cosmetic flavoring agent and food additive. Therefore, the development of a method for directly converting erythritol to 1,4-anhydroerythritol ketal has important scientific significance and application prospects for the efficient utilization of bio-based erythritol and the development of its downstream market. Summary of the invention

[0003] The object of the present invention is to provide a method for directly synthesizing 1,4-anhydroerythritol ketal from bio-based erythritol. The method adopts a one-pot one-step method, and uses bio-based erythritol and ketone compounds to undergo a one-step dehydration-ketalization reaction under the catalysis of a solid acid to generate a 1,4-anhydroerythritol ketal product having a 1,3-dioxolane structure. The method has the advantages of short reaction process, simple operation, mild reaction conditions, easy product separation, recyclable catalyst, and environmental friendliness.

[0004]

[0005] In one aspect of the present application, a method for preparing 1,4-anhydroerythritol ketal compound is provided, wherein bio-based erythritol is used as a reaction raw material, and 1,4-anhydroerythritol ketal is generated by solid acid catalysis in the presence of a fatty ketone reagent.

[0006] Optionally, the method specifically includes: mixing bio-based erythritol with a fatty ketone reagent and a solid acid catalyst, and reacting in one step to generate a 1,4-anhydroerythritol ketal product having a 1,3-dioxolane structure.

[0007] Optionally, the fatty ketone reagent is a 3～9 Ketone compounds;

[0008] Optionally, the aliphatic ketone reagent is selected from at least one of acetone, butanone, 2-pentanone, 3-pentanone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, 2-hexanone, 3-hexanone, methyl isobutyl ketone, 5-methyl-2-hexanone, diisopropyl ketone, methyl levulinate, ethyl levulinate, propyl levulinate, and butyl levulinate.

[0009] Fatty ketone compounds serve as reaction reagents and reaction media in the reaction process of directly converting erythritol to prepare 1,4-anhydroerythritol ketal.

[0010] Optionally, the solid acid catalyst is selected from at least one of hydrogen-type zeolite molecular sieve, Keggin-type heteropoly acid, and heteropoly acid salt.

[0011] Optionally, the hydrogen-type zeolite molecular sieve is selected from at least one of H-ZSM-5, H-Beta, HY, and H-MOR.

[0012] Optionally, the Keggin type heteropoly acid is selected from Keggin type phosphotungstic heteropoly acid (H3PW 12 O 40 ), silicotungstic heteropoly acid (H4SiW 12 O 40 ) at least one of.

[0013] Optionally, the heteropoly acid salt is selected from silver phosphotungstate (Ag X PW 12 O 40 , X = 1 ~ 3), cesium phosphotungstate (Cs X PW 12 O 40 ,X=1~3)at least one.

[0014] The direct preparation of 1,4-anhydroerythritol ketal from erythritol requires a dehydration reaction and a ketalization reaction. Both reactions are typical acid-catalyzed reactions, so the use of an acid catalyst is the key to this one-step synthesis.

[0015] Optionally, the molar ratio of the fatty ketone reagent to erythritol is 70:1 to 1:1.

[0016] Optionally, the upper limit of the molar ratio of the fatty ketone agent to erythritol can be independently selected from 70:1, 60:1, 50:1, 40:1, 30:1, 20:1, 15:1, 5:1; the lower limit can be independently selected from 60:1, 50:1, 40:1, 30:1, 20:1, 15:1, 5:1, 1:1;

[0017] When the molar ratio of fatty ketone reagents to erythritol is lower than 1:1, the utilization rate of erythritol raw materials is low, and the viscosity of the reaction solution is high, which can easily lead to incomplete ketalization of 1,4-anhydroerythritol, resulting in side reactions such as accumulation or polymerization of 1,4-anhydroerythritol intermediates; when the molar ratio of fatty ketone reagents to erythritol is higher than 70:1, the acid catalyst is excessively diluted by the fatty ketone reagent, the acidic site concentration is reduced, resulting in reduced catalyst activity, and ultimately leading to a lower erythritol conversion rate.

[0018] Optionally, the mass ratio of the solid acid catalyst to erythritol is 0.5-50%.

[0019] Optionally, the upper limit of the mass ratio of the solid acid catalyst to erythritol can be independently selected from 2%, 5%, 10%, 25%, 30%, 40%, 50%; the lower limit can be independently selected from 0.5%, 2%, 5%, 10%, 25%, 30%, 40%;

[0020] When the amount of catalyst is too low, the reactant molecules cannot fully contact with the acidic center of the catalyst, resulting in a low conversion rate of erythritol; when the amount of catalyst is greater than 50% of the substrate erythritol, the yield of 1,4-anhydroerythritol ketal does not increase significantly.

[0021] Optionally, the reaction temperature is 100-170°C;

[0022] Optionally, the upper temperature limit of the reaction may be independently selected from 120°C, 130°C, 140°C, 150°C, 170°C; the lower temperature limit may be independently selected from 100°C, 120°C, 130°C, 140°C, 150°C;

[0023] When the reaction temperature is lower than 100°C, although the ketalization reaction is easy to occur, the intramolecular dehydration reaction is difficult to proceed at this temperature, so erythritol ketal is mainly generated, and the yield of the target product 1,4-anhydroerythritol ketal is low; when the reaction temperature is higher than 170°C, side reactions such as polymerization are intensified, and humic acid is easily generated, resulting in a decrease in the selectivity of 1,4-anhydroerythritol ketal.

[0024] Optionally, the reaction time is 0.5 to 12 hours;

[0025] Optionally, the upper limit of the reaction time can be independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 10 hours, and 12 hours; the lower limit can be independently selected from 0.5 hours, 1 hour, 2 hours, 3 hours, 5 hours, and 10 hours.

[0026] Optionally, the reaction is carried out under closed conditions.

[0027] In the initial stage of the reaction, erythritol first undergoes ketalization reaction with ketone compounds, mainly generating erythritol ketal intermediates with 1,3-dioxolane structure; as the reaction time increases, the ketal intermediates undergo further intramolecular dehydration catalyzed by acid to generate 1,4-anhydroerythritol, which then undergoes ketalization reaction to generate the final product 1,4-anhydroerythritol ketal. If the reaction time exceeds 12 hours, further extension of the reaction time is likely to aggravate side reactions such as polymerization, resulting in a decrease in the yield of 1,4-anhydroerythritol ketal.

[0028] The beneficial effects of this application include:

[0029] The raw material erythritol of the method of the present invention is a natural four-carbon sugar alcohol widely distributed in nature. In the presence of a ketone reagent, it is converted by environmentally friendly solid acid catalysis to generate 1,4-anhydroerythritol ketal in one step, and the yield of the obtained product can reach more than 80%. The reaction process is short, the operation is simple, the reaction conditions are mild, the product is easy to separate, and the catalyst can be recycled and reused, which opens up an efficient method for directly preparing 1,4-anhydroerythritol ketal from bio-based erythritol. DETAILED DESCRIPTION

[0030] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0031] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0032] Silver phosphotungstate is prepared by ion exchange between phosphotungstic acid and silver nitrate; cesium phosphotungstate is prepared by ion exchange between phosphotungstic acid and cesium carbonate.

[0033] The analysis method in the examples of this application is as follows:

[0034] The conversion rate of erythritol was determined by high performance liquid chromatography (HPLC); the yields of 1,4-anhydroerythritol ketal product and 1,4-anhydroerythritol intermediate were determined by gas chromatography.

[0035] The calculation formulas for conversion rate and yield in this application are as follows:

[0036] Erythritol conversion rate % = (1-unreacted molar amount of erythritol / initial molar amount of erythritol) × 100%

[0037] 1,4-anhydroerythritol ketal yield % = 1,4-anhydroerythritol ketal generated molar amount / erythritol initial molar amount × 100%

[0038] 1,4-anhydroerythritol yield % = 1,4-anhydroerythritol generated molar amount / erythritol initial molar amount × 100%

[0039] Example 1

[0040] Erythritol and 3-pentanone were put into the reactor, H-ZSM-5 (SiO2 / Al2O3=80) molecular sieve catalyst was added, the reactor was sealed, the temperature was raised to 150°C, and the reaction was carried out by magnetic stirring for 3 hours. Among them, the molar ratio of 3-pentanone to erythritol was 20:1, and the mass ratio of H-ZSM-5 catalyst to erythritol was 15%. After the reaction was completed, the reactor was quickly cooled to room temperature, and the conversion rate of erythritol was determined by high performance liquid chromatography (HPLC); the yields of 1,4-anhydroerythritol acetal product and 1,4-anhydroerythritol intermediate were determined by gas chromatography. The reaction results were expressed in molar percentage (mol%). The conversion rate of erythritol was 100%, the yield of the target product 1,4-anhydroerythritol acetal 3-pentanone was 91%, and the yield of 1,4-anhydroerythritol intermediate was 5%.

[0041] Example 2

[0042] Erythritol and ketone reagents were put into the reactor, phosphotungstic heteropoly acid catalyst was added, the reactor was sealed, the temperature was raised to 130°C, and the reaction was stirred magnetically for 10 hours. Among them, the molar ratio of ketone reagent to erythritol was 50:1, and the mass ratio of phosphotungstic heteropoly acid catalyst to erythritol was 5%. After the reaction was completed, the reactor was quickly cooled to room temperature, and the erythritol conversion rate was determined by high performance liquid chromatography (HPLC); the yields of 1,4-anhydroerythritol ketal product and 1,4-anhydroerythritol intermediate were determined by gas chromatography. The reaction results were expressed in molar percentage (mol%), as shown in Table 1.

[0043] Table 1: Reaction results of preparing 1,4-anhydroerythritol ketal from erythritol catalyzed by phosphotungstic acid in the presence of different ketone reagents.

[0044]

[0045]

[0046] Example 3

[0047] Put erythritol and methyl isopropyl ketone into the reactor and add H-Beta

[0048] (SiO2 / Al2O3=25) molecular sieve catalyst, closed reactor, heated to 140°C, magnetic stirring reaction for 5 hours. Among them, the mass ratio of H-Beta catalyst to erythritol is 10%. After the reaction is completed, the reactor is quickly cooled to room temperature, and the erythritol conversion rate is determined by high performance liquid chromatography (HPLC); gas chromatography is used to determine the yield of 1,4-anhydroerythritol acetal product and 1,4-anhydroerythritol intermediate. The reaction results are expressed in molar percentage (mol%), as shown in Table 2.

[0049] Table 2: Reaction results of preparing 1,4-anhydroerythritol ketal by H-Beta catalyzed erythritol at different amounts of methyl isopropyl ketone.

[0050]

[0051] In Table 2, R1 is the molar ratio of methyl isopropyl ketone to erythritol.

[0052] Example 4

[0053] Erythritol and 2-hexanone were put into the reactor, and phosphotungstate (Ag2HPW 12 O 40 ) catalyst, a closed reactor, heated to a certain temperature, and reacted for 5 hours with magnetic stirring, wherein the molar ratio of 2-hexanone to erythritol was 60:1, Ag2HPW 12 O 40 The mass ratio of the catalyst to erythritol is 30%. After the reaction is completed, the reactor is quickly cooled to room temperature, and the erythritol conversion rate is determined by high performance liquid chromatography (HPLC); the yields of 1,4-anhydroerythritol ketal product and 1,4-anhydroerythritol intermediate are determined by gas chromatography. The reaction results are expressed in molar percentage (mol%), as shown in Table 3.

[0054] Table 3: Silver phosphotungstate (Ag2HPW) at different temperatures 12 O 40 ) catalyzes the reaction of erythritol in 2-hexanone to prepare 1,4-anhydroerythritol ketal.

[0055]

[0056] Example 5

[0057] Erythritol and butyl levulinate were put into the reactor, and cesium phosphotungstate (Cs 2.5 PW 12 O 40 ) catalyst, a closed reactor, the temperature was raised to 140°C, and the reaction was stirred magnetically for a certain period of time, wherein the molar ratio of butyl levulinate to erythritol was 15:1, Cs2.5 PW 12 O 40 The mass ratio of the catalyst to erythritol is 30%. After the reaction is completed, the reactor is quickly cooled to room temperature, and the erythritol conversion rate is determined by high performance liquid chromatography (HPLC); the yields of 1,4-anhydroerythritol ketal product and 1,4-anhydroerythritol intermediate are determined by gas chromatography. The reaction results are expressed in molar percentage (mol%), as shown in Table 4.

[0058] Table 4: Cs at different reaction times 2.5 PW 12 O 40 The reaction results of catalyzing erythritol to prepare 1,4-anhydroerythritol ketal in butyl levulinate.

[0059]

[0060] Example 6

[0061] Erythritol and methyl isopropyl ketone were put into the reactor, and HY (SiO2 / Al2O3=30) molecular sieve catalyst was added. The reactor was closed, heated to 170°C, and magnetically stirred for 1 hour, wherein the molar ratio of methyl isopropyl ketone to erythritol was 10:1. After the reaction was completed, the reactor was quickly cooled to room temperature, and the yields of 1,4-anhydroerythritol acetal product and 1,4-anhydroerythritol intermediate were determined by gas chromatography. The reaction results were expressed in molar percentage (mol%), as shown in Table 5.

[0062] Table 5: Reaction results of erythritol converted into 1,4-anhydroerythritol ketal in methyl isopropyl ketone at different HY molecular sieve catalyst dosages.

[0063]

[0064] In Table 5, R2 is the mass percentage of HY molecular sieve catalyst and erythritol.

[0065] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a 1,4-anhydroerythritol ketal compound, characterized in that: Using erythritol as the reaction raw material, in the presence of a fatty ketone reagent, 1,4-anhydroerythritol ketal is generated by solid acid catalysis; The method specifically comprises: mixing erythritol with a fatty ketone reagent and a solid acid catalyst, and reacting in one step to generate a 1,4-anhydroerythritol ketal product having a 1,3-dioxolane structure; The solid acid catalyst is selected from at least one of hydrogen-type zeolite molecular sieve, Keggin-type heteropoly acid, and heteropoly acid salt; The hydrogen-type zeolite molecular sieve is selected from at least one of H-ZSM-5, H-Beta, HY, and H-MOR; The Keggin type heteropoly acid is selected from at least one of a Keggin type phosphotungstic heteropoly acid and a silicotungstic heteropoly acid; The heteropoly acid salt is selected from at least one of silver phosphotungstate and cesium phosphotungstate; The aliphatic ketone reagent is selected from at least one of acetone, butanone, 2-pentanone, 3-pentanone, methyl isopropyl ketone, cyclopentanone, cyclohexanone, 2-hexanone, 3-hexanone, methyl isobutyl ketone, 5-methyl-2-hexanone, diisopropyl ketone, methyl levulinate, ethyl levulinate, propyl levulinate, and butyl levulinate.

2. The method according to claim 1, characterized in that The molar ratio of the fatty ketone reagent to erythritol is 70:1-1:

1.

3. The method according to claim 1, characterized in that The mass ratio of the solid acid catalyst to erythritol is 0.5-50%.

4. The method according to claim 1, characterized in that The reaction temperature is 100-170°C; The reaction time is 0.5 to 12 hours.

5. The method according to claim 1, characterized in that: The reaction is carried out under closed conditions.

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