Use of a supported solid base catalyst in alkyl glycosides

Abstract

The application discloses a preparation method of a supported solid base catalyst and application of the supported solid base catalyst in alkyl polyglycoside, and belongs to the field of organic synthesis catalysis technology and green chemistry. The novel supported solid base catalyst has the following advantages: high alkaline site density, a catalytic efficiency which is 25-40% higher than that of KOH, and a reaction time which is shortened by 20-30%; by adjusting the ratio of alkaline earth metal and rare earth metal in the catalyst, the average addition number of butylene oxide can be accurately controlled, the content of the target product is greater than or equal to 95%; the catalyst is green, environment-friendly, equipment-friendly, non-corrosive, can prolong the service life of a reaction kettle and reduce industrialization cost; the initial height of foam of the synthetic product is reduced by 60-80% compared to that of a traditional process, and the residual amount of foam is less than 20 mL after 5 minutes. The novel supported solid base catalyst prepared by the application is applied to alkyl polyglycoside to generate alkyl polyglycoside polyoxybutylene ether, which not only retains some excellent performances of alkyl polyglycoside, but also has obvious low-foaming performance, can save a large amount of industrial water, and can meet the requirements of fast decontamination, easy rinsing and environmental protection.

Description

Technical Field

[0001] This invention relates to the fields of organic synthesis catalysis technology and green chemistry, specifically to the application of a supported solid base catalyst in alkyl glycosides, and more particularly to a green synthesis process that uses a solid base to replace a traditional base catalyst. Background Technology

[0002] Alkyl glycosides (APG) are currently recognized internationally as "green" functional surfactants. They have low surface tension, no cloud point, adjustable HLB value, strong wetting power, strong detergency, strong compatibility, are non-toxic, harmless, and non-irritating to the skin. They are biodegradable quickly and thoroughly, can be compounded with any type of surfactant, have obvious synergistic effects, and produce rich, delicate and stable foam.

[0003] In large-scale industrial cleaning and dyeing industries, foam not only affects decontamination but also makes rinsing difficult, easily leaving residues and even overflowing from the cleaning equipment, resulting in waste. Furthermore, foam carries away some surfactants from the cleaning solution, reducing surfactant concentration and thus decreasing detergency. Therefore, defoamers or low-foaming cleaning products are needed. Surfactants are the main factor in foam generation in cleaning agents. Under these practical conditions, surfactants that do not produce foam or whose foam is unstable and disappears quickly are considered low-foaming surfactants and have wide applications.

[0004] Currently available alkyl glycoside products exhibit foam accumulation, particularly in industrial cleaning and textile dyeing fields, where excessive foam significantly reduces application efficiency. Research indicates that targeted modification of the glycosyl backbone with multiple hydroxyl groups can effectively develop low-foaming surfactants. However, existing technologies have limitations: CN109503824A describes modifying the alkyl glycoside backbone with ethylene oxide groups, but the hydrophilic properties of ethylene oxide result in persistently high foaming power; while patent CN110894290B uses propylene oxide for structural modification to obtain alkyl glycoside polyoxypropylene ethers, its foam suppression effect still fails to meet expectations.

[0005] Alkyl glycoside polyoxybutylene ether, a specialty surfactant possessing both low-foaming properties and environmental friendliness, is synthesized from alkyl glycosides (APG0810) and epoxide (BO) via a chain propagation reaction under catalysis. Traditional processes often employ strong alkaline catalysts such as KOH and NaOH, but suffer from four significant drawbacks:

[0006] ① High risk of corrosion: The high corrosiveness of the catalyst can easily lead to serious wear and tear on equipment such as reactors and pipelines, significantly increasing the frequency of equipment maintenance and production costs;

[0007] ②Complex post-processing: After the reaction, neutralization, refining and other processes must be carried out to remove catalyst residues, which not only greatly increases the pressure of waste treatment, but also runs counter to the concept of green chemistry;

[0008] ③ Difficulty in directional control: Existing catalytic systems are difficult to precisely control the average number of additions of epoxide (1~4), resulting in a wide molecular weight distribution of the product and insufficient structural uniformity;

[0009] ④ Poor recycling: The single-pass consumption characteristic of catalysts leads to low utilization rate, resulting in serious resource waste and increased production costs.

[0010] In summary, constructing an innovative supported solid base catalytic system that is highly efficient, stable, environmentally compatible, and recyclable has become an important research direction for overcoming the technical bottlenecks in the synthesis of alkyl glycoside polyoxybutylene ethers, realizing catalyst recycling, and promoting the sustainable development of the surfactant industry. Summary of the Invention

[0011] The purpose of this invention is to provide a supported solid base catalyst to overcome the shortcomings of existing catalysts and improve the efficiency of synthesis reactions and product quality.

[0012] An application of a supported solid base catalyst in alkyl glycosides, wherein the supported solid base catalyst is an alkaline earth metal-rare earth metal composite oxide solid base, comprising the following preparation steps:

[0013] S1. Preparation of precursor: Dissolve the metal nitrate corresponding to the active component and the carrier precursor in deionized water in proportion, add 2-4 mol / L NaOH solution dropwise under stirring at 50-70℃, adjust the pH to 9-11, and form a suspension.

[0014] The active component is composed of alkaline earth metal oxides and rare earth metal oxides in a mass ratio of (3~5):(1~2), accounting for 60%~85% of the total mass. The support is mesoporous SiO2, Al2O3 or TiO2, with a specific surface area ≥200m². 2 / g, pore volume ≥0.5cm 3 / g, accounting for 15%~40% by mass;

[0015] S2. Aging and Washing: After aging the suspension for 2-4 hours, filter and wash with deionized water until no Cl is present. — The product was tested with silver nitrate and a solid product was obtained.

[0016] S3. Drying and calcination: The solid product is dried at 100~120℃ for 12~24 hours and calcined in a muffle furnace at 500~700℃ for 3~5 hours with a heating rate of 5℃ / min to obtain a solid base catalyst.

[0017] The prepared supported solid base catalyst was applied to alkyl glycosides. Under the action of the solid base catalyst, the polyhydroxyl groups on the glycosyl backbone of alkyl glycoside APG0810 underwent a ring-opening addition reaction with epoxide to generate alkyl glycoside polyoxybutylene ether, as shown in the following reaction formula:

[0018]

[0019] The addition number of epoxide is 1 to 4.

[0020] Furthermore, the alkaline earth metal oxide in step S1 is one of MgO and CaO, the rare earth metal oxide is one of La2O3 and CeO2, and the metal nitrate corresponding to the active component is Mg(NO3)2, Ca(NO3)2, La(NO3)3 and Ce(NO3)3.

[0021] Furthermore, the carrier in step S1 is mesoporous SiO2, Al2O3, or TiO2, with a specific surface area ≥200 m². 2 / g, pore volume ≥0.5cm 3 / g, accounting for 15%~40% by mass.

[0022] Furthermore, the supported solid base catalyst is a particulate solid with a basic site density ≥2.0 mmol / g and an average particle size of 20~50 μm.

[0023] Furthermore, the supported solid base catalyst is used in the synthesis of alkyl glycoside polyoxybutylene ethers, comprising the following steps:

[0024] a. In the reactor, the crude alkyl glycoside product APG0810 and the solid base catalyst are melt-mixed at a mass ratio of (50-200):1, purged three times with high-purity nitrogen, and heated to 130°C under oxygen-free conditions to carry out the dehydration reaction.

[0025] b. Then, epoxide is introduced and reacted at a temperature of 130~180℃ until the end of the reaction, with a reaction time of 3~5 hours. After aging and cooling to 80℃, the solid base catalyst is filtered out and recycled.

[0026] c. Finally, adjust the pH of the system to 6.5-7.0 with an acidic neutralizing agent, and the filtered product is alkyl glycoside polyoxybutylene ether.

[0027] Furthermore, the solid base catalyst can be recycled 5 to 8 times.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The supported solid base catalyst obtained by this invention has the following advantages:

[0030] (1) High efficiency catalysis: The density of alkaline sites is high, the catalytic efficiency is 25-40% higher than that of KOH, and the reaction time is shortened by 20-30%;

[0031] (2) Precise control: By adjusting the ratio of alkaline earth metals to rare earth metals in the catalyst, the average number of additions of epoxide can be precisely controlled, and the content of the target product is ≥95%;

[0032] (3) Green and environmentally friendly: The catalyst can be reused, there is no wastewater discharge, and it complies with the EU REACH regulations;

[0033] (4) Equipment friendly: non-corrosive, extending the service life of the reactor and reducing industrialization costs;

[0034] (5) Excellent low foaming performance: The initial height of the foam of the synthesized product is reduced by 60-80% compared with the traditional process, and the foam residue is <20mL after 5 minutes.

[0035] The supported solid base catalyst prepared by this invention is applied to alkyl glycosides to generate alkyl glycoside polyoxybutylene ether. It not only retains some of the excellent properties of alkyl glycosides, but also has obvious low foaming properties, which can save a lot of industrial water and meet the requirements of fast decontamination, easy rinsing and environmental protection. Detailed Implementation

[0036] The present invention will be further illustrated by the following embodiments, but is not limited to these embodiments and application examples.

[0037] Example 1: MgO-La2O3 / SiO2 solid base catalyst

[0038] Weigh 21.4 g of Mg(NO3)2·6H2O and 43.3 g of La(NO3)3·6H2O, dissolve them in 200 mL of water, add 71 mL of sodium silicate solution containing 15 g of SiO2, add 3 mol / L NaOH dropwise until pH=10, and age for 3 hours; after filtration and washing, dry at 110℃ for 16 hours, and calcine at 600℃ for 4 hours to obtain a catalyst with a mass ratio of MgO:La2O3:SiO2=7:3:3. The sodium silicate solution containing 15 g of SiO2 is prepared as follows: Weigh 100 g of industrial sodium silicate with a modulus of 3.3, of which SiO2 accounts for 75%, dissolve it in deionized water and dilute to 500 mL to obtain a 20% concentration sodium silicate solution with a density of 1.4 g / mL.

[0039] Example 2: CaO-CeO2 / Al2O3 solid base catalyst

[0040] Weigh 16.4g of Ca(NO3)2·4H2O and 32.0g of Ce(NO3)3·6H2O, dissolve them in 150mL of water, add 28.6mL of sodium aluminate solution containing 20g of Al2O3, add NaOH dropwise until pH=9, and age for 4 hours; after filtration and washing, dry at 110℃ for 16 hours and then calcine at 550℃ for 5 hours to obtain a CaO:CeO2:Al2O3=8:2:2 (mass ratio) catalyst. The preparation method of the sodium aluminate solution containing 20g of Al2O3 is as follows: Weigh 40g of industrial sodium aluminate (Al2O3 content 50%), dissolve it in deionized water and make up to 100mL to obtain a 40% sodium aluminate solution with a density of 1.4g / mL.

[0041] Example 3: MgO-CeO2 / TiO2 solid base catalyst

[0042] Weigh 21.4 g of Mg(NO3)2·4H2O and 32.0 g of Ce(NO3)3·6H2O, dissolve them in 150 mL of water, add 139 mL of a titanium oxysulfate aqueous solution containing 20 g of TiO2, add NaOH dropwise until pH=11, and age for 2 hours; after filtration and washing, dry at 110℃ for 16 hours and calcine at 550℃ for 5 hours to obtain a catalyst with a mass ratio of MgO:CeO2:TiO2=7:2:2. The preparation method of the titanium oxysulfate aqueous solution containing 20 g of TiO2 is as follows: dissolve 15 g of titanium sulfate in 85 g of deionized water to obtain a 15% titanium sulfate aqueous solution with a density of 1.2 g / mL.

[0043] Application Example 1

[0044] In a high-pressure reactor, 380 kg of crude alkyl glycoside product APG0810 and 3.8 kg of MgO-La2O3 / SiO2 solid base catalyst were melt-mixed and purged three times with high-purity nitrogen. The mixture was then heated to 130°C under anaerobic conditions for a dehydration reaction for 1 hour. Then, 70 kg of BO was introduced, and the reaction was continued at 160°C for 3.2 hours (until the epoxide conversion rate was ≥99%), at a rate of 21.9 kg BO / h. The mixture was then aged at 160°C for 1 hour, cooled to 80°C, and the solid base catalyst was filtered out. Finally, citric acid was added to adjust the pH of the system to 6.5-7.0, yielding alkyl glycoside polyoxybutylene ether APG0810BO. The addition number was measured to be 1.0. After several uses, the addition number changed to 1.8 on the sixth use, indicating that the MgO-La2O3 / SiO2 solid base catalyst can be recycled five times.

[0045] In Application Example 1, the catalytic efficiency reached 21.9 kg BO / h, which is 40.4% higher than that of KOH catalyst (15.6 kg BO / h); the reaction time was shortened to 3.2 hours, which is 28.9% shorter than that of KOH (4.5 hours).

[0046] Application Example 2

[0047] In a high-pressure reactor, 380 kg of crude alkyl glycoside product APG0810 and 3.8 kg of CaO-CeO2 / Al2O3 solid base catalyst were melt-mixed and purged three times with high-purity nitrogen. Under anaerobic conditions, the mixture was heated to 130°C for a dehydration reaction for 1 hour. Then, 140 kg of BO was introduced, and the reaction was carried out at 160°C for 4.0 hours (until the epoxide butane conversion rate was ≥99%). The reaction rate was 35.0 kg BO / h. The mixture was then aged at 160°C for 1 hour, cooled to 80°C, and the solid base catalyst was filtered out. Finally, citric acid was added to adjust the pH of the system to 6.5~7.0 to obtain alkyl glycoside polyoxybutylene ether APG0810BO2. The addition number was measured to be 2.1. After several uses, the addition number changed to 2.7 on the 9th use. The CaO-CeO2 / Al2O3 solid base catalyst can be recycled 8 times.

[0048] Application Example 3

[0049] In a high-pressure reactor, 380 kg of crude alkyl glycoside product APG0810 and 3.8 kg of MgO-La2O3 / SiO2 solid base catalyst were melt-mixed and purged three times with high-purity nitrogen. The mixture was then heated to 130°C under anaerobic conditions for a dehydration reaction for 1 hour. Then, 210 kg of BO was introduced, and the reaction was continued at 160°C for 4.5 hours (until the epoxide butane conversion rate was ≥99%), at a rate of 46.7 kg BO / h. The mixture was then aged at 160°C for 1 hour, cooled to 80°C, and the solid base catalyst was filtered out. Finally, citric acid was added to adjust the pH of the system to 6.5-7.0, yielding alkyl glycoside polyoxybutylene ether APG0810BO3. The addition number was measured to be 3.1. After several uses, the addition number changed to 3.8 on the 8th use. The MgO-La2O3 / SiO2 solid base catalyst can be recycled 7 times.

[0050] Application Example 4

[0051] In a high-pressure reactor, 380 kg of crude alkyl glycoside product APG0810 and 3.8 kg of MgO-La2O3 / SiO2 solid base catalyst were melt-mixed and purged three times with high-purity nitrogen. The mixture was then heated to 130°C under anaerobic conditions for a dehydration reaction for 1 hour. Then, 280 kg of BO was introduced, and the reaction was continued at 160°C for 5.0 hours (until the epoxide butane conversion rate was ≥99%), at a rate of 56.0 kg BO / h. The mixture was then aged at 160°C for 1 hour, cooled to 80°C, and the solid base catalyst was filtered out. Finally, citric acid was added to adjust the pH of the system to 6.5-7.0, yielding alkyl glycoside polyoxybutylene ether APG0810BO4. The addition number was measured to be 4.0. After several uses, the addition number changed to 4.6 on the 7th use. The MgO-La2O3 / SiO2 solid base catalyst can be recycled 6 times.

[0052] The data show that the catalyst’s high efficiency was verified in the synthesis of BO1 to BO4.

[0053] Comparative Example 1

[0054] In a high-pressure reactor, 380 kg of crude alkyl glycoside product APG0810 and 4.4 kg of traditional catalyst KOH were melt-mixed and purged three times with high-purity nitrogen. Under anaerobic conditions, the mixture was heated to 130°C for a dehydration reaction for 1 hour. Then, 70 kg of BO was introduced, and the reaction was carried out at 160°C for 4.5 hours (until the epoxide butane conversion rate was ≥99%). The reaction rate was 15.6 kg BO / h. The mixture was then aged at 160°C for 1 hour, cooled to 80°C, and finally, citric acid was added to adjust the pH of the system to 6.5~7.0 to obtain alkyl glycoside polyoxybutylene ether APG0810BO. The addition number was measured to be 1.8, but 500 L of wastewater was generated during the process.

[0055] Comparative Example 2

[0056] Following the same procedure as Comparative Example 1, 380 kg of APG0810 and 4.4 kg of KOH were melt-mixed in a high-pressure reactor. After nitrogen purging, the mixture was heated to 130°C for dehydration for 1 hour. Then, 140 kg of BO was introduced, and the reaction was carried out at 160°C for 5.0 hours (until the conversion rate was ≥99%). The reaction rate was 28.0 kg BO / h. After aging, the mixture was cooled and neutralized to obtain a product with an addition number of 2.8, generating 500 L of wastewater.

[0057] Comparative Example 3

[0058] The same procedure was followed, with 210 kg of BO introduced and the reaction proceeding for 5.6 hours (until the conversion rate was ≥99%). The reaction rate was 37.3 kg BO / h, yielding a product with an addition number of 3.5 and generating 500 L of wastewater.

[0059] Comparative Example 4

[0060] The same procedure was followed, with 280 kg of BO introduced and the reaction carried out for 6.2 hours (until the conversion rate was ≥99%). The reaction rate was 44.8 kg BO / h, yielding a product with an addition number of 4.2 and generating 500 L of wastewater.

[0061] The addition number test method in the application examples and comparative examples is as follows: The addition number (n) is determined by nuclear magnetic resonance hydrogen spectroscopy (NMR spectroscopy). 1 The average value was calculated based on the integral area ratio of glycosyl terminal anomeric hydrogen (δ ≈ 4.5-5.5 ppm) to polyoxybutene chain-terminal methyl hydrogen (δ ≈ 1.0-1.2 ppm) or methylene hydrogen (δ ≈ 3.3-3.7 ppm) by H NMR (400 MHz, D2O).

[0062] The product parameters of Application Examples 1-4 and Comparative Examples are shown in Table 1:

[0063] Table 1

[0064]

[0065] The surface tension and foam properties test results of Application Examples 1-4 and the comparative sample are shown in Table 2:

[0066] Table 2

[0067]

[0068] Note: The test method for foam performance is the Ross-Miles method.

[0069] The efficiency comparisons between Application Examples 1-4 and the comparative sample are shown in Table 3:

[0070] Table 3

[0071]

[0072] As shown in Table 2, the series of alkyl glycoside polyoxybutylene ether samples prepared using the catalyst of this invention are low-foaming nonionic surfactants. Their initial foam height is significantly lower than that of APG0810. Although the product performance changes little when using conventional catalysts, the amount of catalyst used will increase. For example, the amount of KOH used with conventional catalysts is about 1.16 times that of solid alkali, which is about 15.8%, and a large amount of wastewater will be generated.

[0073] As shown in Table 3, under the same BO feed amount, the reaction rate of the solid base catalyst of this invention is significantly higher than that of KOH (increased by 25%~40%); the time required to complete the same scale reaction is shortened by 20%~30%; the efficiency advantage remains stable as the reaction scale increases (BO 70→280kg); the solid base catalyst achieves precise control (addition number deviation ≤0.1), while the addition number of KOH products deviates from the target value by 0.7~1.8.

[0074] In summary, these are merely preferred embodiments of the present invention and are not intended to limit the scope of the invention. All equivalent variations and modifications made in accordance with the shape, structure, features and spirit described in the claims of the present invention should be included within the scope of the claims of the present invention.

Claims

1. The application of a supported solid base catalyst in alkyl glycosides, characterized in that: The supported solid base catalyst is an alkaline earth metal-rare earth metal composite oxide solid base, and includes the following preparation steps: S1. Preparation of precursor: Dissolve the metal nitrate corresponding to the active component and the carrier precursor in deionized water in proportion, add 2-4 mol / L NaOH solution dropwise under stirring at 50-70℃, adjust the pH to 9-11, and form a suspension. The active component is composed of alkaline earth metal oxides and rare earth metal oxides in a mass ratio of (3~5):(1~2), accounting for 60%~85% of the total mass. The support is mesoporous SiO2, Al2O3 or TiO2, with a specific surface area ≥200m². 2 / g, pore volume ≥0.5cm 3 / g, accounting for 15%~40% by mass; S2. Aging and Washing: After aging the suspension for 2-4 hours, filter and wash with deionized water until no Cl is present. — The product was tested with silver nitrate and a solid product was obtained. S3. Drying and calcination: The solid product is dried at 100~120℃ for 12~24 hours and calcined in a muffle furnace at 500~700℃ for 3~5 hours with a heating rate of 5℃ / min to obtain a solid base catalyst. The prepared supported solid base catalyst was applied to alkyl glycosides. Under the action of the solid base catalyst, the polyhydroxyl groups on the glycosyl backbone of alkyl glycoside APG0810 underwent a ring-opening addition reaction with epoxide to generate alkyl glycoside polyoxybutylene ether, as shown in the following reaction formula: The addition number of epoxide is 1 to 4.

2. The application of the supported solid base catalyst according to claim 1 in alkyl glycosides, characterized in that: The alkaline earth metal oxide in step S1 is one of MgO and CaO, the rare earth metal oxide is one of La2O3 and CeO2, and the metal nitrate corresponding to the active component is Mg(NO3)2, Ca(NO3)2, La(NO3)3 and Ce(NO3)3.

3. The application of the supported solid base catalyst according to claim 1 in alkyl glycosides, characterized in that: The supported solid base catalyst is a particulate solid with a basic site density ≥2.0 mmol / g and an average particle size of 20~50 μm.

4. The application of the supported solid base catalyst according to claim 1 in alkyl glycosides, characterized in that: The supported solid base catalyst is used in the synthesis of alkyl glycoside polyoxybutylene ethers, including the following steps: a. In the reactor, the crude alkyl glycoside product APG0810 and the solid base catalyst are melt-mixed at a mass ratio of (50-200):1, purged three times with high-purity nitrogen, and heated to 130°C under oxygen-free conditions to carry out the dehydration reaction. b. Then, epoxide is introduced and reacted at a temperature of 130~180℃ until the end of the reaction, with a reaction time of 3~5 hours. After aging and cooling to 80℃, the solid base catalyst is filtered out and recycled. c. Finally, adjust the pH of the system to 6.5-7.0 with an acidic neutralizing agent, and the filtered product is alkyl glycoside polyoxybutylene ether.

5. The application of the supported solid base catalyst according to claim 4 in alkyl glycosides, characterized in that: The solid base catalyst can be recycled 5 to 8 times.

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