A solid organic acid catalyst and its preparation method

Abstract

The present invention discloses a solid organic acid catalyst, which comprises a strongly acidic cation exchange resin and a metal chloride; the strongly acidic cation exchange resin has a structure shown in Formula A below, where n = 60 - 180; the metal chloride is selected from one of aluminum chloride, iron chloride or chromium chloride. The strongly acidic cation exchange resin is prepared by reacting the product of the reaction of allyl bromide and N-(glycidyl)-N-phenyl-oxiranemethanamine with divinylbenzene, and then sulfonating with sodium aminosulfonate. The solid organic acid catalyst provided by the present invention has good stability, a long service life, strong catalytic ability and specific catalytic performance.

Description

Technical Field

[0001] The present invention relates to the field of catalyst synthesis, and particularly relates to a solid organic acid catalyst and a preparation method thereof. Background Art

[0002] A catalyst generally refers to a substance that can increase the reaction rate without changing the total standard Gibbs free energy change of the reaction. According to statistics, more than 90% of industrial processes use catalysts, such as chemical industry, petrochemical industry, biochemical industry, environmental protection, etc. There are various types of catalysts. According to the state, they can be divided into liquid catalysts and solid catalysts; according to the phase state of the reaction system, they can be divided into homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts include acids, bases, soluble transition metal compounds, and peroxide catalysts. Among them, acid catalysts have quite extensive applications.

[0003] An acid catalyst refers to a catalyst that forms an active carbocation intermediate compound (the main way of activation) by donating a proton or accepting an electron pair between the catalyst and the reactant molecules, and then decomposes into products. It includes liquid acid catalysts and solid acid catalysts.

[0004] Among them, the most widely used acid catalysts are liquid acid catalysts, such as sulfuric acid, hydrofluoric acid, hydrochloric acid, etc. They are generally used in homogeneous acid catalysis processes. They are in sufficient contact with the reactants, but it is difficult to achieve continuous production. At the same time, liquid acids will corrode equipment. And some liquid acids, such as sulfuric acid, in addition to acid catalysis performance, also have oxidizing, dehydrating, and sulfonating abilities, which can cause many side reactions, and thus cause serious environmental pollution.

[0005] A solid acid catalyst (such as strongly acidic cation exchange resin, acidic molecular sieve, supported superacid, etc.) refers to a solid that can donate protons or accept electron pairs, and also refers to a solid that can change the color of a basic indicator or chemically adsorb basic substances. It is commonly used in heterogeneous acid catalysis processes. Compared with liquid acid catalysts, it has higher stability and selectivity, can be recycled repeatedly for multiple times, is environmentally friendly, and can achieve process continuity, thus greatly expanding the application scope of acid catalysis. Among them, strongly acidic cation exchange resin is a kind of functional polymer compound with a network structure with functional groups. It is composed of an insoluble three-dimensional network skeleton, functional groups connected to the skeleton, and exchangeable ions with opposite charges carried by the functional groups, and is widely used in water treatment, food industry, synthetic chemistry, petrochemical industry, and other aspects.

[0006] However, the strongly acidic cation exchange resin in the prior art has poor stability, the active components are easy to lose, and the service life is short; the catalytic performance is not specific, and many side reactions will be caused; the contact area with the reactants is insufficient, and the catalytic ability is poor. Summary of the Invention

[0007] Object of the Invention: Aiming at the defects of the prior art, the object of the present invention is to provide a solid organic acid catalyst with good stability, long service life, strong catalytic ability and specific catalytic performance, and a preparation method thereof.

[0008] Technical Solution:

[0009] A solid organic acid catalyst comprises a strongly acidic cation exchange resin and a metal chloride;

[0010] The strongly acidic cation exchange resin has the structure shown in Formula A as follows:

[0011]

[0012] where n = 60 - 180.

[0013] The solid organic acid catalyst of the present invention comprises a strongly acidic cation exchange resin and a metal chloride, has strong catalytic ability and strong selectivity and specificity for esterification reaction.

[0014] Further, the metal chloride is selected from one of aluminum chloride, ferric chloride or chromium chloride; the mass ratio of the strongly acidic cation exchange resin to the metal chloride is 3 - 5:1.

[0015] Further, the strongly acidic cation exchange resin is prepared by the following steps:

[0016] (1) By reacting allyl bromide with N-(glycidyl)-N-phenyl-epoxyethanemethylamine, a compound shown in Formula B is prepared:

[0017]

[0018] (2) By reacting divinylbenzene with the compound of Formula B, a compound shown in Formula C is prepared:

[0019] where n = 60 - 180;

[0020] (3) The strongly acidic cation exchange resin is prepared by reacting the compound C with sodium aminosulfonate.

[0021] The strongly acidic cation exchange resin of the present invention has excellent stability through multiple aromatic functional groups in its structure, and thus has a very long service life and can be recycled multiple times.

[0022] Further, the specific method of step (1) is as follows: In a reactor, add N-(glycidyl)-N-phenyl-epoxyethanemethylamine and an organic solvent, stir and mix evenly, under nitrogen protection, heat up to 35-45°C, then slowly dropwise add allyl bromide, with the dropping time being 2-3 hours. After the dropping is completed, heat up to 50-55°C and keep the temperature for reaction for 18-24 hours. Then remove the solvent and recrystallize to obtain the compound of formula B.

[0023] Further, the molar ratio of N-(glycidyl)-N-phenyl-epoxyethanemethylamine to allyl bromide is 1:1-1.2.

[0024] Further, the specific method of step (2) is as follows: In a reactor, add divinylbenzene, the compound of formula B and an initiator, stir evenly, then heat up to 80-95°C and react for 4-6 hours, and then cool to room temperature. Filter, wash and dry to obtain the compound of formula C.

[0025] Further, the initiator is selected from one of benzoyl peroxide, tert-butyl peroxybenzoate or methyl ethyl ketone peroxide; the molar ratio of divinylbenzene to the compound of formula B is 1:2-2.2.

[0026] Further, the specific method of step (3) is as follows: In a reactor, add the compound of formula C and swell with tetrahydrofuran for 8-12 hours, then add sodium sulfamate and an aqueous sodium hydroxide solution, heat up to 80-100°C, keep the temperature for reaction for 16-24 hours, and then cool to room temperature. Filter, wash and dry to obtain the strong acidic cation exchange resin.

[0027] The strong acidic cation exchange resin of the present invention has multiple sulfonic acid functional groups, and they are dispersed in multiple branched chains, which can quickly participate in the reaction of reactants and have excellent catalytic ability; and it contains multiple aromatic functional groups and multiple branched chain structures, and thus has a relatively long arm chain, which is easy to react with other substances and perform ion exchange; due to its quaternary ammonium structure and aromatic structure, it has a relatively large steric hindrance, which increases the contact volume with the reactants, and thus has excellent catalytic ability.

[0028] Further, the mass ratio of the compound of formula C to sodium sulfamate is 2-3:1.

[0029] The preparation method of the solid organic acid catalyst described in any one of the above, includes the following steps: In a reactor, add the strong acidic cation exchange resin and metal chloride to an organic solvent, heat up to 80-90°C, keep the temperature for reaction for 16-24 hours, and then cool to room temperature. Filter, wash and dry to obtain the solid organic acid catalyst.

[0030] In the preparation process of the strongly acidic cation exchange resin of the present invention, sulfonation is not carried out using sulfonic acid, which reduces environmental pollution and also reduces the difficulty of product separation and purification.

[0031] Advantages:

[0032] 1. The solid organic acid catalyst provided by the present invention contains a strongly acidic cation exchange resin and a metal chloride, has strong catalytic ability and has strong selectivity and specificity for esterification reactions.

[0033] 2. The strongly acidic cation exchange resin is used in the solid organic acid catalyst provided by the present invention. Through multiple aromatic functional groups in its structure, it has excellent stability, and thus has a long service life and can be recycled multiple times.

[0034] 3. The strongly acidic cation exchange resin is used in the solid organic acid catalyst provided by the present invention. It has multiple sulfonic acid functional groups, and they are dispersed in multiple branched chains, and can quickly participate in the reaction with reactants, and has excellent catalytic ability.

[0035] 4. The strongly acidic cation exchange resin is used in the solid organic acid catalyst provided by the present invention. It contains multiple aromatic functional groups and multiple branched chain structures, and thus has a relatively long arm chain, which is easy to react with other substances and undergo ion exchange; due to its quaternary ammonium structure and aromatic structure having relatively large steric hindrance, the contact volume with reactants is increased, and thus it has excellent catalytic ability.

[0036] 5. In the preparation process of the strongly acidic cation exchange resin in the solid organic acid catalyst provided by the present invention, sulfonation is not carried out using sulfonic acid, which reduces environmental pollution and also reduces the difficulty of product separation and purification. Specific embodiments

[0037] The following will illustrate the present invention in combination with specific implementation schemes. It should be noted that the following examples are examples of the present invention, only for illustrating the present invention, rather than for limiting the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

[0038] The commercially available solid acid catalyst is a sulfuric acid / zirconia solid acid catalyst purchased from Qinzhou Yamei Chemical Co., Ltd.; the commercially available cation exchange resin is a D001 macroporous cation exchange resin purchased from Langfang Xingnuo Thermal Insulation Materials Co., Ltd.; the rest of the reagents and equipment are conventional reagents and equipment in the technical field.

[0039] Preparation of strongly acidic cation exchange resin-1

[0040] The strongly acidic cation exchange resin-1 is prepared through the following steps:

[0041] (1) In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen protection device, add 0.02 mol of N-(glycidyl)-N-phenyl-epoxyethanemethylamine and 100 mL of absolute ethanol. Stir and mix evenly. After heating to 40 °C under nitrogen protection, slowly dropwise add 0.022 mol of allyl bromide over 3 hours. After the addition is complete, heat to 50 °C and keep the temperature for 18 hours. Then remove the solvent and obtain the compound of formula B after recrystallization;

[0042] Mass spectrometry data of formula B: The product was analyzed by LC-MS. The m / z of the product was 246.15 (100.0%), 247.18 (17.2%), 248.15 (1.5%).

[0043] (2) In a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, add 0.01 mol of divinylbenzene, 0.022 mol of the compound of formula B, and 0.05 g of benzoyl peroxide. Stir evenly and then heat to 90 °C for 6 hours. After cooling to room temperature, perform suction filtration, washing, and drying to obtain the compound of formula C;

[0044] (3) In a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, add 10 g of the compound of formula C and 100 mL of tetrahydrofuran to swell for 8 - 12 hours. Then add 5 g of sodium sulfamate and 20 mL of a 40% by mass aqueous sodium hydroxide solution. Heat to 90 °C and keep the temperature for 24 hours. After cooling to room temperature, perform suction filtration, washing, and drying to obtain the strong acidic cation exchange resin - 1.

[0045] Preparation of strong acidic cation exchange resin - 2

[0046] Basically the same as the preparation of strong acidic cation exchange resin - 1, except that step (1) is not carried out. The compound of formula B in step (2) is replaced with an equal amount of glycidyl methacrylate, and the compound of formula C in step (3) is replaced with an equal amount of the product of step (2).

[0047] Example 1

[0048] The solid organic acid catalyst was prepared through the following steps:

[0049] In a reactor, add 5 g of the strong acidic cation exchange resin - 1 and 1 g of aluminum chloride to 50 mL of absolute ethanol. Heat to 90 °C and keep the temperature for 24 hours. After cooling to room temperature, perform suction filtration, washing, and drying to obtain the solid organic acid catalyst.

[0050] Example 2

[0051] Basically the same as Example 1, except that aluminum chloride is replaced with an equal amount of chromium chloride.

[0052] Example 3

[0053] Basically the same as Example 1, except that 5 g of strongly acidic cation exchange resin-1 is changed to 3 g of strongly acidic cation exchange resin-1.

[0054] Comparative Example 1

[0055] Commercially available solid acid catalyst.

[0056] Comparative Example 2

[0057] Basically the same as Example 1, except that cation exchange resin-1 is changed to an equal amount of commercially available cation exchange resin.

[0058] Comparative Example 3

[0059] Cation exchange resin-1.

[0060] Comparative Example 4

[0061] Basically the same as Example 1, except that cation exchange resin-1 is changed to an equal amount of cation exchange resin-2.

[0062] Performance test

[0063] 1. Exchange capacity detection: The exchange capacities of the products of Examples 1-3 and Comparative Examples 1-4 were detected according to the detection method of cation exchange resin exchange capacity in GB-T 8144-2008.

[0064] 2. Sulfonic acid group content detection: The surface acid amount of the catalyst was determined by neutralization titration method: The products of Examples 1-3 and Comparative Examples 1-4 and NaCl solution were placed in a conical flask and stirred at room temperature for 4 h to make the H + in the catalyst fully exchange with Na + . After filtering the product, it was titrated with NaOH solution to calculate the sulfonic acid group content.

[0065] Exchange capacity IEC (meq / g) Sulfonic acid group content (W%) Example 1 4.46 28.7 Example 2 4.52 28.5 Example 3 4.47 28.2 Comparative Example 1 1.74 7.4 Comparative Example 2 2.23 12.6 Comparative Example 3 4.23 29.7 Comparative Example 4 2.64 15.7

[0066] According to the comparison of the detection results of Examples 1-3 and Comparative Example 1, the solid organic acid catalyst provided by the present invention combines a strongly acidic cation exchange resin and a metal chloride, has a large exchange capacity and sulfonic acid group content, and thus has excellent catalytic ability.

[0067] According to the comparison of the detection results of Examples 1-3 and Comparative Examples 2-4, the strongly acidic cation exchange resin added in the solid organic acid catalyst provided by the present invention has excellent exchange capacity and sulfonic acid group content.

[0068] 3. Detection of reactivity: The products of Examples 1-3 and Comparative Examples 1-4 were crushed to 30-60 mesh, 2 ml was taken and loaded into a reaction tube with an inner diameter of 1 cm. 12 g of acetic acid and 10 g of ethanol were fed as raw materials per hour. The reaction temperature was set at 110 °C, and the reaction products were analyzed by gas chromatography to detect the reaction conversion rate and the selectivity of ethyl acetate.

[0069] 4. Detection of service life: The products of Examples 1-3 and Comparative Examples 1-4 were used to replace sulfuric acid in the ethyl acetate production process and continuously operated. Samples were taken for analysis every 4 h to detect the reactivity, and the reactivity of the catalyst at 4000 h, 5000 h and 6000 h was recorded.

[0070]

[0071] According to the comparison of the detection results of Examples 1-3 and Comparative Example 1, the solid organic acid catalyst provided by the present invention combines a strongly acidic cation exchange resin and a metal chloride, has excellent catalytic ability and selectivity for esterification reaction, and has a very long service life.

[0072] According to the comparison of the detection results of Examples 1-3 and Comparative Examples 2-4, the strongly acidic cation exchange resin added in the solid organic acid catalyst provided by the present invention, based on the polysulfonic acid groups in its structure and combined with a metal chloride, has excellent catalytic ability and high selectivity for esterification reaction; and the multi-branched chains and multi-aromatic groups in the structure of the strongly acidic cation exchange resin endow it with excellent stability, making the solid organic acid catalyst have a very long service life.

[0073] The above embodiments are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A solid organic acid catalyst, characterized in that, It contains a strongly acidic cation exchange resin and a metal chloride; The strongly acidic cation exchange resin has the structure shown in Formula A below: ， where n = 60 - 180; The metal chloride is selected from one of aluminum chloride, iron chloride or chromium chloride; the mass ratio of the strongly acidic cation exchange resin to the metal chloride is 3 - 5:

1.

2. The solid organic acid catalyst according to claim 1, wherein The strongly acidic cation exchange resin is prepared by the following steps: (1) By reacting allyl bromide with N-(glycidyl)-N-phenyl-epoxyethanemethylamine, the compound shown in Formula B below is obtained: ； (2) By reacting divinylbenzene with the compound of Formula B, the compound shown in Formula C below is obtained: , where n = 60 - 180; (3) The strongly acidic cation exchange resin is obtained by reacting Compound C with sodium sulfamate.

3. The solid organic acid catalyst according to claim 2, wherein, The specific method of step (1) is: In a reactor, add N-(glycidyl)-N-phenyl-epoxyethanemethylamine and an organic solvent, stir and mix evenly, after heating to 35 - 45 °C under nitrogen protection, slowly dropwise add allyl bromide, the dropping time is 2 - 3 hours, after the dropping is completed, heat to 50 - 55 °C, keep the temperature for reaction for 18 - 24 hours, then remove the solvent, and obtain the compound of Formula B after recrystallization.

4. The solid organic acid catalyst according to claim 3, wherein The molar ratio of N-(glycidyl)-N-phenyl-epoxyethanemethylamine to allyl bromide is 1:1 - 1.

2.

5. The solid organic acid catalyst according to claim 2, wherein The specific method of step (2) is: In a reactor, add divinylbenzene, the compound of Formula B and an initiator, stir evenly and then heat to 80 - 95 °C for reaction for 4 - 6 hours, then cool to room temperature, filter by suction, wash and dry to obtain the compound of Formula C.

6. The solid organic acid catalyst according to claim 5, characterized in that, The initiator is selected from one of benzoyl peroxide, tert-butyl peroxybenzoate or methyl ethyl ketone peroxide; the molar ratio of divinylbenzene to the compound of Formula B is 1:2 - 2.

2.

7. The solid organic acid catalyst according to claim 2, characterized in that, The specific method of step (3) is: In a reactor, add the compound of Formula C and swell with tetrahydrofuran for 8 - 12 hours, then add sodium sulfamate and an aqueous sodium hydroxide solution, heat to 80 - 100 °C, keep the temperature for reaction for 16 - 24 hours, then cool to room temperature, filter by suction, wash and dry to obtain the strongly acidic cation exchange resin.

8. The solid organic acid catalyst according to claim 7, wherein The mass ratio of the compound of Formula C to sodium sulfamate is 2 - 3:

1.

9. The preparation method of the solid organic acid catalyst according to any one of claims 1-8, characterized in that, It includes the following steps: In a reactor, add the strongly acidic cation exchange resin and the metal chloride to an organic solvent, heat to 80 - 90 °C, keep the temperature for reaction for 16 - 24 hours, then cool to room temperature, filter by suction, wash and dry to obtain the solid organic acid catalyst.

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