Method for one-step catalytic synthesis of isosorbide methyl ether

Abstract

The invention discloses a method for one-step catalytic synthesis of isosorbide methyl ether, which comprises the following steps: mixing raw materials containing sorbitol, ethylene glycol dimethyl ether and a solid acid catalyst, and reacting in a closed container to obtain a product containing isosorbide methyl ether, the solid acid catalyst is selected from at least one of Keggin type heteropolyacid, sulfonic acid functionalized ionic liquid heteropolyacid salt, strong acid type ion exchange resin, a hydrogen type zeolite molecular sieve and an acid modified hydrogen type zeolite molecular sieve. According to the method, biomass platform molecular sorbitol is directly used as a raw material, and isosorbitol monomethyl ether and isosorbitol dimethyl ether are generated in one step in one pot under the catalysis of solid acid with intramolecular dehydration and etherification functions in the absence of a solvent or in the presence of a solvent. The method has the advantages that the raw materials are cheap and easy to obtain, the synthesis route is short, the operation is simple, the requirement on equipment is low, separation and purification of an intermediate product isosorbide are not needed, the etherification efficiency is high, and the total yield of the isosorbide methyl ether is 50% or above.

Description

Technical Field

[0001] The present application relates to a one-step catalytic synthesis method of isosorbide methyl ether, belonging to the field of chemical synthesis. Background Art

[0002] Sorbitol is an important biomass platform compound that can be directly produced from naturally abundant carbohydrates such as glucose, starch, and cellulose. Its inherent multi-hydroxy structure characteristics are the key and challenge in the high-value utilization of sorbitol, so the optimal utilization of hydroxyl groups is an important means to achieve efficient utilization of sorbitol. Among them, the selective removal-modification strategy of hydroxyl groups can increase the value of sorbitol to isosorbide and isosorbide derivatives, completely retaining the six-carbon skeleton, thereby achieving efficient utilization of the multi-hydroxyl structure of sorbitol.

[0003] Isosorbide, as an important secondary dehydration product of sorbitol, is a bio-based functional diol with excellent properties such as rigidity, chirality and non-toxicity. Its dihydroxyl functional group is further converted into high-value-added oxygen-containing derivatives through chemical modifications such as etherification and esterification, and is widely used in medicine, cosmetics, food, polymers and other fields. It is worth noting that isosorbide methyl ether is a recognized bio-based high-boiling point green solvent, and it has recently been reported to be used as an anti-aging agent in cosmetics or dermatological compositions, which has important application value.

[0004] At present, the synthesis of isosorbide methyl ether mainly uses pure isosorbide as raw material, and is prepared by etherification reaction with methylating agents through acid or base catalysis. The continuous deepening of green chemistry and sustainable development concepts has greatly promoted the development of low-toxic and environmentally friendly methylating agents to replace traditional highly toxic methylating agents such as dimethyl sulfate and methyl halides. Based on this, new green methylating agents such as methanol, dimethyl carbonate, and ethylene glycol dimethyl ether have been reported in the literature, which provides a feasible route for the green synthesis of isosorbide methyl ether. At present, the industrial preparation of isosorbide is to catalyze the secondary dehydration of sorbitol under vacuum conditions with liquid strong acids such as concentrated sulfuric acid as catalysts, but this preparation method has a large number of competing side reaction routes, such as non-selective dehydration, polymerization and other side reactions, resulting in low isosorbide yield and sorbitol raw material utilization. In addition, due to the high boiling point and thermal instability of isosorbide itself, the separation and purification of isosorbide requires high temperature and high vacuum, which is a high-cost, high-energy consumption process, and is accompanied by serious isosorbide product losses. Therefore, although using pure isosorbide as the raw material for synthesizing isosorbide methyl ether can obtain a higher yield, the high cost of the isosorbide raw material seriously hinders the practical application of isosorbide methyl ether. Summary of the invention

[0005] In summary, seeking to use cheap and readily available biomass platform molecule sorbitol as a raw material to directly synthesize isosorbide methyl ether in one step provides a new route for the efficient utilization of biomass. It avoids the separation and purification of isosorbide intermediates, simplifies the operation steps, shortens the synthesis time, and improves the synthesis efficiency of isosorbide methyl ether. It has important scientific significance and application prospects.

[0006] The purpose of the present invention is to provide a novel and efficient method for preparing isosorbide methyl ether, which has the advantages of cheap and readily available raw materials, simple operation, fewer reaction steps, and short synthesis time, and realizes environmentally friendly green catalytic synthesis of isosorbide methyl ether. The method of the present invention has the advantages of cheap and readily available raw materials, fewer reaction steps, simple operation, low equipment requirements, avoiding the separation and purification of the intermediate product isosorbide, high etherification efficiency, etc., and the total yield of isosorbide methyl ether is above 50%.

[0007] According to one aspect of the present application, a one-step catalytic synthesis method of isosorbide methyl ether is provided, comprising the following steps:

[0008] Sorbitol, ethylene glycol dimethyl ether and a solid acid catalyst are mixed and reacted in a closed container without or with a solvent to obtain a product containing isosorbide methyl ether;

[0009] The reaction process is as follows:

[0010]

[0011] The sorbitol is a biomass platform molecule.

[0012] The solid acid catalyst is selected from at least one of Keggin-type heteropolyacid, sulfonic acid functionalized ionic liquid heteropolyacid salt, strong acid ion exchange resin, hydrogen-type zeolite molecular sieve, and acid-modified hydrogen-type zeolite molecular sieve.

[0013] The Keggin type heteropoly acid is selected from at least one of phosphotungstic heteropoly acid and silicotungstic heteropoly acid;

[0014] The sulfonic acid functionalized ionic liquid heteropolyacid salt is selected from 1-(3-sulfonic acid)propyl-3-methylimidazolium phosphotungstate ([MIMPS]3PW 12 O 40 ), 1-(4-sulfonic acid)butyl-3-methylimidazolium phosphotungstate ([MIMBS]3PW 12 O 40 )1-(3-sulfonic acid)propylpyridinium phosphotungstate ([PyPS]3PW 12 O 40 ), 1-(4-sulfonic acid)butylpyridinium phosphotungstate ([PyBS]3PW 12 O 40), 1-(3-sulfonic acid)propyl-3-methylimidazolium tungstate ([MIMPS]4SiW 12 O 40 ), 1-(4-sulfonic acid)butyl-3-methylimidazolium tungstate ([MIMBS]4SiW 12 O 40 ), 1-(3-sulfonic acid)propylpyridinium tungstosilicoate ([PyPS]4SiW 12 O 40 ) or 1-(4-sulfonic acid)butylpyridinium tungstate ([PyBS]4SiW 12 O 40 )

[0015] The strong acid ion exchange resin is selected from at least one of Amberlyst-36, Amberlyst-70, and Nafion-H (NR50);

[0016] The hydrogen-type zeolite molecular sieve is selected from H-beta molecular sieve;

[0017] The acid-modified hydrogen-type zeolite molecules are selected from at least one of phosphoric acid-modified H-beta, citric acid-modified H-beta, tartaric acid-modified H-beta, and oxalic acid-modified H-beta.

[0018] The molar ratio of the ethylene glycol dimethyl ether to the sorbitol is 5:1 to 120:1;

[0019] Optionally, the molar ratio of ethylene glycol dimethyl ether to sorbitol is 10:1 to 100:1.

[0020] The mass ratio of the solid acid catalyst to the sorbitol is 0.01:1 to 1.5:1;

[0021] Optionally, the mass ratio of the solid acid catalyst to sorbitol is 0.05:1 to 1:1.

[0022] In the condition of having a solvent, the solvent is selected from at least one of toluene, xylene, cyclohexane, dimethyl carbonate, 1,4-dioxane, acetone, butanone, 2-pentanone, 3-pentanone, methyl isopropyl ketone, methyl isobutyl ketone and 2-hexanone;

[0023] The molar ratio of the solvent to the sorbitol is 1:1 to 70:1;

[0024] Optionally, the molar ratio of the solvent to sorbitol is 2:1 to 50:1.

[0025] The reaction temperature is 150-200°C;

[0026] Optionally, the reaction temperature is 150-190°C.

[0027] The reaction time is 2 to 24 hours;

[0028] The reaction time is 4 to 12 hours.

[0029] The isosorbide methyl ether is selected from isosorbide monomethyl ether and / or isosorbide dimethyl ether, i.e. 2-methoxyisosorbide, 5-methoxyisosorbide and / or isosorbide dimethyl ether.

[0030] The beneficial effects of this application include:

[0031] The present invention directly uses the biomass platform molecule sorbitol as a raw material, uses ethylene glycol dimethyl ether as an etherifying agent, and generates isosorbide monomethyl ether and dimethyl ether in one pot and one step under the condition of no solvent or with solvent through the catalysis of a solid acid having intramolecular dehydration and etherification functions. The synthesis method directly synthesizes isosorbide methyl ether from sorbitol, has the advantages of cheap and easy-to-obtain raw materials, short synthesis route, simple operation, low equipment requirements, no need for separation and purification of the intermediate product isosorbide, high etherification efficiency, and a total yield of isosorbide methyl ether of more than 50%. DETAILED DESCRIPTION

[0032] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0033] The reagents and raw materials used in the present invention are all commercially available. Solid acids including Keggin-type heteropolyacids and hydrogen-type zeolite molecular sieves are all commercially available. Sulfonic acid functionalized ionic liquid heteropolyacid salts are obtained by ion exchange between the corresponding sulfonic acid imidazole or sulfonic acid pyridine inner salt and phosphotungstic acid or heteropolyacid. The acid-modified hydrogen-type zeolite molecular sieve is obtained by immersing the hydrogen-type zeolite molecular sieve in a phosphoric acid, tartaric acid, citric acid or oxalic acid solution through an excess impregnation method.

[0034] Example 1

[0035] Sorbitol, ethylene glycol dimethyl ether and silicotungstic acid H4SiW 12 O 40 Put it into a stainless steel reactor, seal the reactor, and react with magnetic stirring at 160°C. The molar ratio of ethylene glycol dimethyl ether to sorbitol is 25:1, H4SiW 12 O 40 The mass ratio of sorbitol to sorbitol is 0.2:1. After the reaction is completed, the product is quantitatively analyzed by gas chromatography internal standard method and expressed as molar percentage (mol%). Among them, the main products of sorbitol one-step conversion include isosorbide (IS), 2-methoxyisosorbide (2-MMI), 5-methoxyisosorbide (5-MMI) and dimethyl isosorbide (DMI). The reaction results are shown in Table 1.

[0036] Table 1: H4SiW at different reaction times 12 O 40 The reaction results of catalyzing the one-step conversion of sorbitol to prepare isosorbide methyl ether.

[0037]

[0038]

[0039] Example 2

[0040] Sorbitol, ethylene glycol dimethyl ether, aprotic solvent and phosphotungstic acid H3PW 12 O 40 Put it into a stainless steel reactor, seal the reactor, and react at 170°C with magnetic stirring for 5 hours. The molar ratio of ethylene glycol dimethyl ether to sorbitol is 70:1, the molar ratio of aprotic solvent to sorbitol is 25:1, and H3PW 12 O 40 The mass ratio of sorbitol to sorbitol is 0.3:1. After the reaction is completed, the product is quantitatively analyzed by gas chromatography internal standard method and expressed as molar percentage (mol%). The reaction results are shown in Table 2.

[0041] Table 2: H3PW in different aprotic solvents 12 O 40 The reaction results of catalyzing the one-step conversion of sorbitol to prepare isosorbide methyl ether.

[0042]

[0043] Example 3

[0044] Sorbitol, ethylene glycol dimethyl ether, 3-pentanone and H-beta molecular sieve were put into a stainless steel reactor, the reactor was sealed, and magnetic stirring was performed for 6 hours at 170, 180 and 190 ° C. Among them, the molar ratio of ethylene glycol dimethyl ether to sorbitol was 50:1, the molar ratio of methyl isopropyl ketone to sorbitol was 20:1, and the mass ratio of H-beta molecular sieve to sorbitol was 0.1:1. After the reaction was completed, the product was quantitatively analyzed by gas chromatography internal standard method, expressed as molar percentage (mol%). The reaction results are shown in Table 3.

[0045] Table 3: Reaction results of one-step conversion of sorbitol to prepare isosorbide methyl ether catalyzed by H-beta molecular sieve at different reaction temperatures.

[0046]

[0047] Example 4

[0048] Sorbitol, ethylene glycol dimethyl ether and phosphotungstic acid H3PW 12 O40 Put it into a stainless steel reactor, seal the reactor, and react with magnetic stirring at 150℃ for 5 hours. 12 O 40 The mass ratio of sorbitol to sorbitol is 0.3:1. After the reaction is completed, the product is quantitatively analyzed by gas chromatography internal standard method and expressed as molar percentage (mol%). The reaction results are shown in Table 4.

[0049] Table 4: H3PW at different dosages of ethylene glycol dimethyl ether 12 O 40 The reaction results of catalyzing the one-step conversion of sorbitol to prepare isosorbide methyl ether.

[0050]

[0051] R 乙二醇二甲醚 / 山梨醇 : The molar ratio of ethylene glycol dimethyl ether to sorbitol

[0052] Example 5

[0053] Sorbitol, ethylene glycol dimethyl ether, toluene and 1-(3-sulfonic acid)propyl-3-methylimidazolium phosphotungstate ([MIMPS]3PW 12 O 40 ) was put into a stainless steel reactor, the reactor was sealed, and the reaction was carried out at 150°C with magnetic stirring for 10 hours. The molar ratio of ethylene glycol dimethyl ether to sorbitol was 40:1, and the molar ratio of toluene to sorbitol was 10:1. After the reaction was completed, the product was quantitatively analyzed by gas chromatography internal standard method and expressed as molar percentage (mol%). The reaction results are shown in Table 5.

[0054] Table 5: Different 1-(3-sulfonic acid)propyl-3-methylimidazolium phosphotungstate ([MIMPS]3PW 12 O 40 ) catalyst dosage, the reaction results of one-step conversion of sorbitol to prepare isosorbide methyl ether.

[0055]

[0056] R[MIMPS]3PW 12 O 40 / Sorbitol: Mass ratio of 1-(3-sulfonic acid)propyl-3-methylimidazolium phosphotungstate to sorbitol

[0057] Example 6

[0058] Sorbitol, ethylene glycol dimethyl ether, methyl isobutyl ketone and citric acid modified H-beta molecular sieve were put into a stainless steel reactor, the reactor was sealed, and the reaction was carried out at 180°C with magnetic stirring for 8 hours. Among them, the molar ratio of ethylene glycol dimethyl ether to sorbitol was 70:1, the molar ratio of methyl isobutyl ketone to sorbitol was 30:1, and the mass ratio of citric acid modified H-beta molecular sieve to sorbitol was 0.05:1. After the reaction was completed, the product was quantitatively analyzed by gas chromatography internal standard method, expressed as molar percentage (mol%). The reaction results are shown in Table 6.

[0059] Table 6: Reaction results of one-step conversion of sorbitol to prepare isosorbide methyl ether catalyzed by citric acid-modified H-beta molecular sieve at different methyl isobutyl ketone dosages.

[0060]

[0061] R 甲基异丁基酮 / 山梨醇 : The molar ratio of methyl isobutyl ketone to sorbitol

[0062] Example 7

[0063] Sorbitol, ethylene glycol dimethyl ether, methyl isopropyl ketone and Amberlyst-70 are put into a stainless steel reactor, the reactor is sealed, and the reaction is carried out at 190°C with magnetic stirring for 5 hours. Among them, the molar ratio of ethylene glycol dimethyl ether to sorbitol is 60:1, the molar ratio of methyl isopropyl ketone to sorbitol is 20:1, and the mass ratio of Amberlyst-70 to sorbitol is 0.25:1. After the reaction is completed, the product is quantitatively analyzed by gas chromatography internal standard method and expressed as molar percentage (mol%). The yields of isosorbide, 2-methoxyisosorbide (2-MMI), 5-methoxyisosorbide (5-MMI) and dimethyl isosorbide (DMI) obtained are 16%, 15%, 13% and 23%, respectively, that is, the total yield of isosorbide methyl ether is 51%.

[0064] 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 one-step catalytic synthesis method of isosorbide methyl ether, characterized in that: The following steps are involved: Sorbitol, ethylene glycol dimethyl ether and a solid acid catalyst are mixed and reacted in a closed container to obtain a product containing isosorbide methyl ether; The solid acid catalyst is selected from at least one of Keggin-type heteropolyacid, sulfonic acid functionalized ionic liquid heteropolyacid salt, strong acid ion exchange resin, hydrogen-type zeolite molecular sieve, and acid-modified hydrogen-type zeolite molecular sieve.

2. The method according to claim 1, characterized in that The Keggin type heteropoly acid is selected from at least one of phosphotungstic heteropoly acid and silicotungstic heteropoly acid; The sulfonic acid functionalized ionic liquid heteropolyacid salt is selected from at least one of 1-(3-sulfonic acid)propyl-3-methylimidazolium phosphotungstate, 1-(4-sulfonic acid)butyl-3-methylimidazolium phosphotungstate, 1-(3-sulfonic acid)propylpyridine phosphotungstate, 1-(4-sulfonic acid)butylpyridine phosphotungstate, 1-(3-sulfonic acid)propyl-3-methylimidazolium silicotungstate, 1-(4-sulfonic acid)butyl-3-methylimidazolium silicotungstate, 1-(3-sulfonic acid)propylpyridine silicotungstate, and 1-(4-sulfonic acid)butylpyridine silicotungstate; The strong acid ion exchange resin is selected from at least one of Amberlyst-36, Amberlyst-70, and Nafion-H; The hydrogen-type zeolite molecular sieve is selected from H-beta molecular sieve; The acid-modified hydrogen-type zeolite molecules are selected from at least one of phosphoric acid-modified H-beta, citric acid-modified H-beta, tartaric acid-modified H-beta, and oxalic acid-modified H-beta.

3. The method according to claim 1, characterized in that The molar ratio of the ethylene glycol dimethyl ether to the sorbitol is 5:1 to 120:1; Preferably, the molar ratio of ethylene glycol dimethyl ether to sorbitol is 10:1 to 100:

1.

4. The method according to claim 1, characterized in that: The mass ratio of the solid acid catalyst to the sorbitol is 0.01:1 to 1.5:1; Preferably, the mass ratio of the solid acid catalyst to sorbitol is 0.05:1 to 1:

1.

5. The method according to claim 1, characterized in that The raw material contains a solvent; The solvent is selected from at least one of toluene, xylene, cyclohexane, dimethyl carbonate, 1,4-dioxane, acetone, butanone, 2-pentanone, 3-pentanone, methyl isopropyl ketone, methyl isobutyl ketone and 2-hexanone; The molar ratio of the solvent to the sorbitol is 1:1 to 70:1; Preferably, the molar ratio of the solvent to sorbitol is 2:1 to 50:

1.

6. The method according to claim 1, characterized in that The reaction temperature is 150-200°C; Preferably, the reaction temperature is 150-190°C.

7. The method according to claim 1, characterized in that The reaction time is 2 to 24 hours; The reaction time is 4 to 12 hours.

8. The method according to claim 1, characterized in that The isosorbide methyl ether is selected from isosorbide monomethyl ether and / or isosorbide dimethyl ether.

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