Application of silica-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate

Abstract

The invention discloses an application of a silica-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate. The dimethyl 2,5-furandicarboxylate is obtained by catalyzing the esterification reaction of 2,5-furandicarboxylic acid and methanol with a silica-sulfonic acid type solid acid catalyst; wherein the silica-sulfonic acid type solid acid catalyst is obtained by grafting, oxidizing and sulfonating silica and a silane coupling agent. The silica-sulfonic acid type solid acid catalyst in the present invention is easy to recover, and has good thermal stability and reusability; the preparation process of dimethyl 2,5-furandicarboxylate provided at the same time has little corrosion to equipment, simple wastewater treatment, mild reaction and high economy.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to application of a silicon dioxide-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate. Background Art

[0002] 2,5-furandicarboxylic acid dimethyl ester is an important bio-based platform compound and a typical derivative of 2,5-furandicarboxylic acid downstream. It has high solubility and good stability and has a good development prospect in the field of polyester synthesis. In existing reports, 2,5-furandicarboxylic acid dimethyl ester is generally synthesized by esterification of 2,5-furandicarboxylic acid and methanol under the catalytic action of concentrated sulfuric acid. This method uses methanol as a solvent and acid-catalyzes esterification of 2,5-furandicarboxylic acid and methanol under normal pressure and heating reflux conditions. However, since the reaction temperature under normal pressure can only reach the boiling point of methanol, and the solubility of 2,5-furandicarboxylic acid in methanol is low, the esterification reaction speed is slow and the single-pot 2,5-furandicarboxylic acid dimethyl ester output is low. In addition, the use of concentrated sulfuric acid is not only more corrosive to equipment and more dangerous, but also brings about problems such as solvent recovery and wastewater treatment, and it is impossible to achieve sustainable and economical synthesis of 2,5-furandicarboxylic acid dimethyl ester. Therefore, there is an urgent need to develop a method for synthesizing dimethyl 2,5-furandicarboxylate, which has simple experimental steps, mild reaction conditions, and simple subsequent processing operations, while ensuring the safety, low cost and environmental sustainability of the process. Summary of the invention

[0003] The main purpose of the present invention is to provide an application of a silicon dioxide-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate, so as to overcome the shortcomings of the prior art.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0005] The embodiment of the present invention provides the use of a silica-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate, wherein the dimethyl 2,5-furandicarboxylate is obtained by esterification reaction of 2,5-furandicarboxylic acid and methanol catalyzed by the silica-sulfonic acid type solid acid catalyst; wherein the silica-sulfonic acid type solid acid catalyst is obtained by grafting, oxidizing and sulfonating silica and a silane coupling agent.

[0006] The embodiment of the present invention also provides a method for preparing dimethyl 2,5-furandicarboxylate, which comprises: reacting a mixed reaction system containing at least 2,5-furandicarboxylic acid, methanol, and a silica-sulfonic acid type solid acid catalyst to obtain dimethyl 2,5-furandicarboxylate;

[0007] The silica-sulfonic acid type solid acid catalyst is prepared by grafting, oxidizing and sulfonating silica and a silane coupling agent.

[0008] Compared with the prior art, the present invention has the following beneficial effects:

[0009] (1) The silica-sulfonic acid type solid acid catalyst in the present invention significantly improves its catalytic esterification activity and target product selectivity;

[0010] (2) The silica-sulfonic acid type solid acid catalyst of the present invention is easy to recover and has good thermal stability and reusability;

[0011] (3) The preparation of dimethyl 2,5-furandicarboxylate by the present invention benefits from the high selectivity of the target product, and a high-purity product can be obtained by simple rotary evaporation, and the refining cost is low;

[0012] (4) The silica-sulfonic acid type solid acid catalyst catalyzed 2,5-furandicarboxylic acid esterification experiment in the present invention is easy to scale up, and the post-treatment operation is simple and environmentally friendly, and has industrial application prospects;

[0013] (5) The preparation process of dimethyl 2,5-furandicarboxylate provided by the present invention has low corrosion to equipment, simple wastewater treatment, mild reaction, high economic efficiency, and simpler experimental operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 Schematic diagram of the reaction of dimethyl 2,5-furandicarboxylate prepared in a typical embodiment of the present invention. DETAILED DESCRIPTION

[0016] In view of the defects of the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Specifically, as one aspect of the technical solution of the present invention, it relates to the use of a silica-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate, wherein the dimethyl 2,5-furandicarboxylate is obtained by esterification of 2,5-furandicarboxylic acid and methanol catalyzed by the silica-sulfonic acid type solid acid catalyst; wherein the silica-sulfonic acid type solid acid catalyst is obtained by grafting, oxidizing and sulfonating silica and a silane coupling agent.

[0018] In some preferred embodiments, the preparation method of the silica-sulfonic acid type solid acid catalyst comprises:

[0019] The silicon dioxide as a carrier and the silane coupling agent are subjected to reflux reaction in a solvent to prepare a mercapto-containing precursor;

[0020] Furthermore, the mercapto group-containing precursor is mixed with an oxidant to carry out an oxidation reaction, and then a sulfonating agent is added to carry out a sulfonation treatment to prepare a silica-sulfonic acid type solid acid catalyst.

[0021] Furthermore, the silica is macroporous mesoporous silica, and the pore size of the silica is 2 to 12 nm.

[0022] Further, the silica includes any one or more combinations of MCM-41, SBA-15, FDU-1, SBA-1, and AMS-8, but is not limited thereto.

[0023] Further, the silane coupling agent includes any one or more combinations of 3-mercaptopropyltrimethoxysilane, 1-mercaptomethyltrimethoxysilane, and 3-mercaptobutyltrimethoxysilane, but is not limited thereto.

[0024] Further, the solvent includes toluene, but is not limited thereto.

[0025] Further, the oxidant includes H2O2 solution, but is not limited thereto.

[0026] Preferably, the concentration of the H2O2 solution is 25-35wt%.

[0027] Further, the sulfonating agent includes a sulfuric acid solution, but is not limited thereto.

[0028] Furthermore, the concentration of the sulfuric acid solution is 0.15-0.25 mol / L.

[0029] Furthermore, the mass ratio of the silicon dioxide to the silane coupling agent is 5:1 to 1:5.

[0030] Furthermore, the mass ratio of the silicon dioxide to the silane coupling agent is 1:1 to 1:3.

[0031] Furthermore, the mass volume ratio of the silane coupling agent to the solvent is 1g:9-11ml.

[0032] Furthermore, the reflux reaction temperature is 110-120° C., and the time is 5-7 hours.

[0033] Furthermore, the mass volume ratio of the thiol-containing precursor to the oxidant is 5g:10-15ml.

[0034] Furthermore, the oxidation reaction temperature is 50-70° C. and the time is 20-30 hours.

[0035] Furthermore, the mass volume ratio of the thiol-containing precursor to the sulfonating agent is 1 g: 10-20 ml.

[0036] Furthermore, the sulfonation treatment is carried out at room temperature for 1 to 5 hours.

[0037] In some more specific embodiments, the method for preparing the silica-sulfonic acid type solid acid catalyst comprises:

[0038] The macroporous mesoporous silica is used as a carrier and silane coupling agent is refluxed in dry toluene to obtain a solid precipitate, which is washed with dry toluene and dried in air at room temperature for 12 hours to obtain a thiol (-SH)-containing precursor; the thiol (-SH)-containing precursor is heated and stirred with an oxidant H2O2 solution, washed with water and ethanol, and then a sulfonating agent sulfuric acid is added and stirred continuously. The solid is thoroughly washed with water and filtered, and dried to obtain a macroporous mesoporous silica-SO3H sulfonic acid type solid acid catalyst (i.e., the aforementioned silica-sulfonic acid type solid acid catalyst).

[0039] Furthermore, the drying temperature is 90-120° C., and the drying time is 10-15 hours.

[0040] Another aspect of the embodiments of the present invention further provides a method for preparing dimethyl 2,5-furandicarboxylate, comprising: reacting a mixed reaction system comprising at least 2,5-furandicarboxylic acid, methanol, and a silica-sulfonic acid type solid acid catalyst to obtain dimethyl 2,5-furandicarboxylate;

[0041] The silica-sulfonic acid type solid acid catalyst is prepared by grafting, oxidizing and sulfonating silica and a silane coupling agent.

[0042] In some preferred embodiments, the reaction diagram of dimethyl 2,5-furandicarboxylate prepared in the present invention is as follows: Figure 1 shown.

[0043] In some preferred embodiments, the preparation method specifically comprises:

[0044] Placing 2,5-furandicarboxylic acid, methanol, and a silica-sulfonic acid type solid acid catalyst in a high-pressure reaction device for esterification reaction;

[0045] And, the obtained product is filtered and an alkaline substance is added to carry out rotary evaporation, crystallization, washing, separation and drying to obtain the dimethyl 2,5-furandicarboxylate.

[0046] Furthermore, the mass ratio of the silica-sulfonic acid type solid acid catalyst to 2,5-furandicarboxylic acid is 0.01 to 1:1.

[0047] Furthermore, the mass ratio of the silica-sulfonic acid type solid acid catalyst to 2,5-furandicarboxylic acid is 0.05-0.5:1.

[0048] Furthermore, the concentration of 2,5-furandicarboxylic acid in the mixed reaction system is 0.05 to 0.65 mol / L.

[0049] Furthermore, the concentration of 2,5-furandicarboxylic acid in the mixed reaction system is 0.25 to 0.45 mol / L.

[0050] Furthermore, the temperature of the esterification reaction is 80-170°C.

[0051] Furthermore, the temperature of the esterification reaction is 100-150°C

[0052] Furthermore, the esterification reaction time is 1 to 12 hours.

[0053] Furthermore, the esterification reaction time is 3 to 7 hours.

[0054] Furthermore, the stirring speed used in the esterification reaction is 300-600 r / min.

[0055] Further, the alkaline substance includes NaHCO3, but is not limited thereto.

[0056] Furthermore, the mass ratio of the alkaline substance to 2,5-furandicarboxylic acid is 1:35-45.

[0057] Furthermore, the rotary evaporation is carried out at a temperature of 80 to 90° C. and for a time of 0.5 to 2 h.

[0058] Furthermore, the crystallization temperature is -5 to 0°C and the time is 10 to 14 hours.

[0059] Furthermore, the mass ratio of water to 2,5-furandicarboxylic acid used in the washing is 10 to 60:1.

[0060] Furthermore, the drying temperature is 40-70°C.

[0061] Furthermore, the drying temperature is 50-60°C.

[0062] Furthermore, the drying process takes 12 to 24 hours.

[0063] Furthermore, the drying process takes 16 to 18 hours.

[0064] In some more specific embodiments, the method for preparing dimethyl 2,5-furandicarboxylate comprises:

[0065] The silica-sulfonic acid type solid acid catalyst is uniformly mixed with 2,5-furandicarboxylic acid and methanol and placed in a high-pressure reactor, heated and stirred to obtain a reaction liquid, dissolved and filtered at room temperature, NaHCO3 is added to the filtrate, and after sufficient stirring, high-temperature rotary evaporation is performed, and crystals are refrigerated to precipitate. After multiple water washing, the crystals are filtered and dried to obtain dimethyl 2,5-furandicarboxylate.

[0066] In some preferred embodiments, the preparation method of the silica-sulfonic acid type solid acid catalyst comprises:

[0067] The silicon dioxide as a carrier and the silane coupling agent are subjected to reflux reaction in a solvent to prepare a mercapto-containing precursor;

[0068] Furthermore, the mercapto group-containing precursor is mixed with an oxidant to carry out an oxidation reaction, and then a sulfonating agent is added to carry out a sulfonation treatment to prepare a silica-sulfonic acid type solid acid catalyst.

[0069] Furthermore, the silica is macroporous mesoporous silica, and the pore size of the silica is 2 to 12 nm.

[0070] Further, the silica includes any one or more combinations of MCM-41, SBA-15, FDU-1, SBA-1, and AMS-8, but is not limited thereto.

[0071] Further, the silane coupling agent includes any one or more combinations of 3-mercaptopropyltrimethoxysilane, 1-mercaptomethyltrimethoxysilane, and 3-mercaptobutyltrimethoxysilane, but is not limited thereto.

[0072] Further, the solvent includes toluene, but is not limited thereto.

[0073] Further, the oxidant includes H2O2 solution, but is not limited thereto.

[0074] Preferably, the concentration of the H2O2 solution is 25-35wt%.

[0075] Further, the sulfonating agent includes a sulfuric acid solution, but is not limited thereto.

[0076] Furthermore, the concentration of the sulfuric acid solution is 0.15-0.25 mol / L.

[0077] Furthermore, the mass ratio of the silicon dioxide to the silane coupling agent is 5:1N1:5.

[0078] Furthermore, the mass ratio of the silicon dioxide to the silane coupling agent is 1:1 to 1:3.

[0079] Furthermore, the mass volume ratio of the silane coupling agent to the solvent is 1g:9-11ml.

[0080] Furthermore, the reflux reaction temperature is 110-120° C., and the time is 5-7 hours.

[0081] Furthermore, the mass volume ratio of the thiol-containing precursor to the oxidant is 5g:10-15ml.

[0082] Furthermore, the oxidation reaction temperature is 50-70° C. and the time is 20-30 hours.

[0083] Furthermore, the mass volume ratio of the thiol-containing precursor to the sulfonating agent is 1 g: 10-20 ml.

[0084] Furthermore, the sulfonation treatment is carried out at room temperature for 1 to 5 hours.

[0085] The silica-sulfonic acid type solid acid catalyst prepared by the present invention has excellent esterification activity and selectivity, can realize high-selective esterification of 2,5-furandicarboxylic acid to generate 2,5-furandicarboxylic acid dimethyl ester, the selectivity of 2,5-furandicarboxylic acid dimethyl ester in the reaction solution is greater than 99.0%, and a high-purity product (99.9%) can be obtained by simple rotary evaporation. The catalyst can be recycled and reused, which greatly reduces the production cost of the product.

[0086] The preparation process of dimethyl 2,5-furandicarboxylate provided by the invention has low corrosion to equipment, simple wastewater treatment, mild reaction, high economy and simpler experimental operation.

[0087] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments. This embodiment is implemented on the premise of the technical solution of the invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0088] The experimental materials used in the examples used below, unless otherwise specified, the raw materials and catalysts in the examples of the present invention were purchased through commercial channels, all purchased from Adamas Group Chemical Reagent Co., Ltd.

[0089] Unless otherwise specified, conventional methods were used for testing methods, and instrument settings were all those recommended by the manufacturer. The composition (purity) analysis method of the product and mother liquor was performed using Agilent's 1260 high performance liquid chromatograph to analyze the products in the 2,5-furandicarboxylic acid esterification reaction.

[0090] Example 1

[0091] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0092] 3.02g of the corresponding macroporous mesoporous silica material MCM-41 and 5.14g of 3-mercaptopropyltrimethoxysilane were accurately weighed, and the two were refluxed in 50mL of dry toluene at 110°C. After reacting for 6h, MCM-41-SH-1 solid was obtained, which was filtered, washed with dry toluene and dried in air for 12h. The obtained solid was continuously stirred with 13mL of 30wt.% H2O2 at 60°C, mildly oxidized at 60°C for 24 hours, filtered to obtain a solid, washed with water and ethanol, and then continuously stirred with 50mL of 0.2M sulfuric acid at room temperature for 2 hours to convert the mercapto group (-SH) into a sulfonic acid group (-SO3H), thoroughly washed with water and filtered, and dried at 100°C for 12 hours to obtain the MCM-41-SO3H-1 catalyst.

[0093] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0094] Accurately weigh 15.0g of 2,5-furandicarboxylic acid into the inner lining of a 250mL autoclave, then add 3.04g of MCM-41-SO3H-1 catalyst and 150mL of methanol, mix well and react at 120°C for 4h at a speed of 400r / min. Add methanol to the reaction solution to 1L, filter to remove solid acid, add 0.383g of NaHCO3 to the filtrate, and condense it to a small amount of liquid at 85°C and refrigerate at 0°C for 12h. Wash the precipitated crystals three times with 150mL of pure water, and then bake them in an oven at 55°C for 17h to obtain 16.71g of off-white solid.

[0095] Example 2

[0096] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0097] Accurately weigh 3.03 g of the corresponding macroporous mesoporous silica material SBA-15 and 5.09 g of 1-mercaptomethyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain MCM-41-SO3H-2 solid. The rest is the same as in Example 1 to obtain MCM-41-SO3H-2 catalyst.

[0098] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0099] 14.99 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.01 g of powdered MCM-41-SO3H-2 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.96 g of an off-white solid was obtained.

[0100] Example 3

[0101] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0102] Accurately weigh 2.97 g of the corresponding macroporous mesoporous silica material SBA-15 and 5.12 g of 3-mercaptobutyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain MCM-41-SO3H-3 solid. The rest is the same as in Example 1 to obtain MCM-41-SO3H-3 catalyst.

[0103] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0104] 15.05 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.01 g of powdered MCM-41-SO3H-3 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 14.58 g of an off-white solid was obtained.

[0105] Example 4

[0106] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0107] Accurately weigh 3.0 g of the corresponding macroporous mesoporous silica material SBA-15 and 5.06 g of 3-mercaptopropyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-15-SH-1 solid. The rest is the same as in Example 1 to obtain SBA-15-SO3H-1 catalyst.

[0108] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0109] 14.97 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.02 g of powdered SBA-15-SO3H-1 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 17.15 g of an off-white solid was obtained.

[0110] Example 5

[0111] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0112] Accurately weigh 3.07 g of the corresponding macroporous mesoporous silica material SBA-15 and 5.02 g of 1-mercaptomethyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-15-SH-2 solid. The rest is the same as in Example 1 to obtain SBA-15-SO3H-2 catalyst.

[0113] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0114] 15.01 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.04 g of powdered SBA-15-SO3H-2 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 17.03 g of an off-white solid was obtained.

[0115] Example 6

[0116] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0117] Accurately weigh 3.01 g of the corresponding macroporous mesoporous silica material SBA-15 and 5.09 g of 3-mercaptobutyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-15-SH-3 solid. The rest is the same as in Example 1 to obtain SBA-15-SO3H-3 catalyst.

[0118] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0119] 15.97 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.02 g of powdered SBA-15-SO3H-3 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 16.62 g of an off-white solid was obtained.

[0120] Example 7

[0121] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0122] Accurately weigh 3.05 g of the corresponding macroporous mesoporous silica material FDU-1 and 5.01 g of 3-mercaptopropyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain FDU-1-SH-1 solid. The rest is the same as in Example 1 to obtain FDU-1-SO3H-1 catalyst.

[0123] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0124] 15.0 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.03 g of powdered FDU-1-SO3H-1 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.73 g of an off-white solid was obtained.

[0125] Example 8

[0126] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0127] Accurately weigh 3.04 g of the corresponding macroporous mesoporous silica material FDU-1 and 5.10 g of 1-mercaptomethyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 h to obtain FDU-1-SH-2 solid. The rest is the same as in Example 1 to obtain FDU-1-SO3H-2 catalyst.

[0128] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0129] 15.06 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.02 g of powdered FDU-1-SO3H-2 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.38 g of an off-white solid was obtained.

[0130] Example 9

[0131] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0132] Accurately weigh 3.07 g of the corresponding macroporous mesoporous silica material FDU-1 and 5.09 g of 3-mercaptobutyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain FDU-1-SH-3 solid. The rest is the same as in Example 1 to obtain FDU-1-SO3H-3 catalyst.

[0133] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0134] 15.05 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.04 g of powdered FDU-1-SO3H-3 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 14.69 g of an off-white solid was obtained.

[0135] Example 10

[0136] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0137] Accurately weigh 3.11 g of the corresponding macroporous mesoporous silica material SBA-1 and 5.02 g of 3-mercaptopropyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-1-SH-1 solid. The rest is the same as in Example 1 to obtain SBA-1-SO3H-1 catalyst.

[0138] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0139] 15.01 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.07 g of powdered SBA-1-SO3H-1 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 16.44 g of an off-white solid was obtained.

[0140] Embodiment 11

[0141] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0142] Accurately weigh 3.08 g of the corresponding macroporous mesoporous silica material SBA-1 and 5.15 g of 1-mercaptomethyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-1-SH-2 solid. The rest is the same as in Example 1 to obtain SBA-1-SO3H-2 catalyst.

[0143] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0144] 15.0 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.05 g of powdered SBA-1-SO3H-2 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 16.24 g of an off-white solid was obtained.

[0145] Example 12

[0146] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0147] Accurately weigh 3.06 g of the corresponding macroporous mesoporous silica material SBA-1 and 5.11 g of 3-mercaptobutyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain SBA-1-SH-3 solid. The rest is the same as in Example 1 to obtain SBA-1-SO3H-3 catalyst.

[0148] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0149] 15.04 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.05 g of powdered SBA-1-SO3H-3 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.51 g of an off-white solid was obtained.

[0150] Example 13

[0151] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0152] Accurately weigh 3.10 g of the corresponding macroporous mesoporous silica material AMS-8 and 5.10 g of 3-mercaptopropyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain AMS-8-SH-1 solid. The rest is the same as in Example 1 to obtain AMS-8-SO3H-1 catalyst.

[0153] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0154] 15.0 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.10 g of powdered AMS-8-SO3H-1 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 16.06 g of an off-white solid was obtained.

[0155] Embodiment 14

[0156] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0157] Accurately weigh 3.06 g of the corresponding macroporous mesoporous silica material AMS-8 and 5.13 g of 1-mercaptomethyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110° C., and react for 6 hours to obtain AMS-8-SH-2 solid. The rest is the same as in Example 1 to obtain AMS-8-SO3H-2 catalyst.

[0158] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0159] 15.02 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.07 g of powdered AMS-8-SO3H-2 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.80 g of an off-white solid was obtained.

[0160] Embodiment 15

[0161] Preparation of silica-SO3H sulfonic acid type solid acid catalyst:

[0162] Accurately weigh 3.01 g of the corresponding macroporous mesoporous silica material AMS-8 and 5.07 g of 3-mercaptobutyltrimethoxysilane, reflux the two in 50 mL of dry toluene at 110°C, and react for 6 hours to obtain AMS-8-SH-3 solid. The rest is the same as in Example 1 to obtain AMS-8-SO3H-3 catalyst.

[0163] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0164] 15.0 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.06 g of powdered AMS-8-SO3H-3 catalyst and 150 mL of methanol were added. The rest was the same as in Example 1, and 15.26 g of an off-white solid was obtained.

[0165] Comparative Example 1

[0166] Preparation of dimethyl 2,5-furandicarboxylate by esterification of 2,5-furandicarboxylic acid:

[0167] 15.04 g of 2,5-furandicarboxylic acid was accurately weighed into the inner lining of a 250 mL autoclave, and then 3.09 g of a commercial sulfonic acid type solid acid catalyst Amberlyst-15 and 150 mL of methanol were added. The rest was the same as in Example 1, and 16.97 g of an off-white solid was obtained.

[0168] Table 1 shows the performance evaluation of different catalysts for catalytic esterification of 2,5-furandicarboxylic acid to prepare dimethyl 2,5-furandicarboxylate.

[0169] Table 1

[0170]

[0171]

[0172] By comparing Examples 1, 4, 7, 10, and 13, MCM-41-SO3H and SBA-15-SO3H catalysts all showed excellent catalytic effects, and the selectivity of the prepared dimethyl 2,5-furandicarboxylate exceeded 99.9%, wherein the catalytic activity of SBA-15-SO3H for esterification of 2,5-furandicarboxylic acid was higher than that of the commercial catalyst Amberlyst-15. This may be due to the fact that the SBA-15 carrier has an ordered hexagonal structure, which can conveniently contain functional groups in its mesoporous framework, and uses different conformations of its organic and inorganic structures to adjust the performance combination. In addition, its large pore size, high surface area, and high thermal stability are also the reasons why SBA-15 can prepare an efficient solid catalyst with better catalytic performance. Compared with other embodiments, it is found that the catalyst prepared by using 3-mercaptopropyltrimethoxysilane as a silane coupling agent has good catalytic performance.

[0173] In addition, the solid acid catalyst prepared in the example was characterized and tested. A broad characteristic peak appeared near 24° in the XRD spectrum, which corresponds to the amorphous structure of silicon dioxide; and a peak at 1079 cm -1 and 1368cm -1 The main characteristic peaks of sulfonic acid groups caused by SO and S=O stretching vibrations appeared nearby. This series of characterization results showed that the silica-SO3H sulfonic acid type solid acid catalyst had been successfully prepared.

[0174] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0175] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. Application of a silica-sulfonic acid type solid acid catalyst in the preparation of dimethyl 2,5-furandicarboxylate, characterized in that: The dimethyl 2,5-furandicarboxylate is obtained by esterification reaction of 2,5-furandicarboxylic acid and methanol catalyzed by a silica-sulfonic acid type solid acid catalyst; wherein the silica-sulfonic acid type solid acid catalyst is obtained by grafting, oxidizing and sulfonating silica and a silane coupling agent.

2. The use according to claim 1, characterized in that: The preparation method of the silica-sulfonic acid type solid acid catalyst comprises: The silicon dioxide as a carrier and the silane coupling agent are subjected to reflux reaction in a solvent to prepare a mercapto-containing precursor; Furthermore, the mercapto group-containing precursor is mixed with an oxidant to carry out an oxidation reaction, and then a sulfonating agent is added to carry out a sulfonation treatment to prepare a silica-sulfonic acid type solid acid catalyst.

3. The use according to claim 2, characterized in that: The silica is macroporous mesoporous silica, and the pore size of the silica is 2 to 12 nm; And / or, the silica includes any one or more combinations of MCM-41, SBA-15, FDU-1, SBA-1, and AMS-8; And / or, the silane coupling agent includes any one or more combinations of 3-mercaptopropyltrimethoxysilane, 1-mercaptomethyltrimethoxysilane, and 3-mercaptobutyltrimethoxysilane, preferably 3-mercaptopropyltrimethoxysilane; and / or, the solvent comprises toluene; And / or, the oxidant comprises H2O2 solution; preferably, the concentration of the H2O2 solution is 25-35wt%; And / or, the sulfonating agent includes a sulfuric acid solution; preferably, the concentration of the sulfuric acid solution is 0.15-0.25 mol / L.

4. The use according to claim 2, characterized in that: The mass ratio of silicon dioxide to silane coupling agent is 5:1 to 1:5, preferably 1:1 to 1:3; And / or, the mass volume ratio of the silane coupling agent to the solvent is 1g:9-11ml; And / or, the reflux reaction temperature is 110-120° C., and the time is 5-7 h; and / or, the mass volume ratio of the thiol-containing precursor to the oxidant is 5 g:10-15 ml; And / or, the oxidation reaction temperature is 50-70°C and the time is 20-30h; and / or, the mass volume ratio of the thiol-containing precursor to the sulfonating agent is 1 g: 10-20 ml; And / or, the sulfonation treatment is carried out at room temperature for 1 to 5 hours.

5. A method for preparing dimethyl 2,5-furandicarboxylate, characterized in that: include: reacting a mixed reaction system containing at least 2,5-furandicarboxylic acid, methanol, and a silica-sulfonic acid type solid acid catalyst to obtain dimethyl 2,5-furandicarboxylate; The silica-sulfonic acid type solid acid catalyst is prepared by grafting, oxidizing and sulfonating silica and a silane coupling agent.

6. The preparation method according to claim 5, characterized in that: Specifically include: Placing 2,5-furandicarboxylic acid, methanol, and a silica-sulfonic acid type solid acid catalyst in a high-pressure reaction device for esterification reaction; And, the obtained product is filtered and an alkaline substance is added to carry out rotary evaporation, crystallization, washing, separation and drying to obtain the dimethyl 2,5-furandicarboxylate.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the silica-sulfonic acid type solid acid catalyst to 2,5-furandicarboxylic acid is 0.01 to 1:1, preferably 0.05 to 0.5:1; and / or, the concentration of 2,5-furandicarboxylic acid in the mixed reaction system is 0.05 to 0.65 mol / L, preferably 0.25 to 0.45 mol / L; and / or, the temperature of the esterification reaction is 80 to 170° C., preferably 100 to 150° C.; And / or, the esterification reaction time is 1 to 12 hours, preferably 3 to 7 hours; And / or, the stirring speed used in the esterification reaction is 300-600 r / min.

8. The preparation method according to claim 6, characterized in that: The alkaline substance includes NaHCO3; and / or, the mass ratio of the alkaline substance to 2,5-furandicarboxylic acid is 1:35-45; And / or, the rotary evaporation adopts a temperature of 80-90° C. and a time of 0.5-2 h; And / or, the crystallization temperature is -5 to 0°C and the time is 10 to 14 hours; And / or, the mass ratio of water to 2,5-furandicarboxylic acid used in the washing is 10 to 60:1; And / or, the drying temperature is 40-70°C, preferably 50-60°C; And / or, the drying treatment time is 12 to 24 hours, preferably 16 to 18 hours.

9. The preparation method according to claim 5, characterized in that: The preparation method of the silica-sulfonic acid type solid acid catalyst comprises: The silicon dioxide as a carrier and the silane coupling agent are subjected to reflux reaction in a solvent to prepare a mercapto-containing precursor; Furthermore, the mercapto group-containing precursor is mixed with an oxidant to carry out an oxidation reaction, and then a sulfonating agent is added to carry out a sulfonation treatment to prepare a silica-sulfonic acid type solid acid catalyst.

10. The preparation method according to claim 9, characterized in that: The silica is macroporous mesoporous silica, and the pore size of the silica is 2 to 12 nm; And / or, the silica includes any one or more combinations of MCM-41, SBA-15, FDU-1, SBA-1, and AMS-8; And / or, the silane coupling agent includes any one or more of 3-mercaptopropyltrimethoxysilane, 1-mercaptomethyltrimethoxysilane, and 3-mercaptobutyltrimethoxysilane; preferably, the silane coupling agent is 3-mercaptopropyltrimethoxysilane; and / or, the solvent comprises toluene; And / or, the oxidant comprises H2O2 solution; preferably, the concentration of the H2O2 solution is 25-35wt%; And / or, the sulfonating agent comprises a sulfuric acid solution; preferably, the concentration of the sulfuric acid solution is 0.15 to 0.25 mol / L; And / or, the mass ratio of silicon dioxide to silane coupling agent is 5:1 to 1:5, preferably 1:1 to 1:3; And / or, the mass volume ratio of the silane coupling agent to the solvent is 1g:9-11ml; And / or, the reflux reaction temperature is 110-120° C., and the time is 5-7 h; and / or, the mass volume ratio of the thiol-containing precursor to the oxidant is 5 g:10-15 ml; And / or, the oxidation reaction temperature is 50-70°C and the time is 20-30h; and / or, the mass volume ratio of the thiol-containing precursor to the sulfonating agent is 1 g: 10-20 ml; And / or, the sulfonation treatment is carried out at room temperature for 1 to 5 hours.

Images