CN1175934C - A kind of tungsten-containing mesoporous molecular sieve catalyst for synthesizing glutaraldehyde and its manufacturing method - Google Patents

Abstract

The invention belongs to the technical field of chemical industry, and relates to a novel heterogeneous tungsten-containing catalyst for selectively oxidizing cyclopentene to prepare glutaraldehyde by using hydrogen peroxide aqueous solution as an oxidant and a manufacturing method thereof. The tungsten-containing catalyst is prepared by introducing tungsten oxide components in situ during the synthesis of SBA-15 type all-silicon mesoporous molecular sieves. The catalyst is characterized by highly dispersed active components and ultra-high loading of tungsten oxide. The heterogeneous catalyst obtained in the present invention is applied in the catalytic selective oxidation reaction of cyclopentene, which greatly improves the selectivity of glutaraldehyde, and its value is much higher than that of the reported homogeneous catalytic level or other heterogeneous solid-supported The level of tungstic acid catalyst has important industrial application value.

Description

A kind of tungsten-containing mesoporous molecular sieve catalyst for synthesizing glutaraldehyde and its manufacturing method

technical field

The invention belongs to the technical field of chemical industry, and relates to a tungsten-containing mesoporous molecular sieve catalyst used for heterogeneous catalytic oxidation of cyclopentene to synthesize glutaraldehyde and a manufacturing method thereof.

Background technique

Glutaraldehyde is a very important chemical product, which is widely used as a disinfectant, a leather tanning agent, a fixative for optical and electron microscope tissue sections, a cross-linking agent for proteins and polyhydroxy compounds, and a micromicelle curing agent, etc. . It is estimated that the total domestic demand for pure glutaraldehyde will reach 20,000 tons/year. Most of the glutaraldehyde currently used in China is imported, and only a few units such as Wuhan Organic Chemical Factory use acrolein to produce it, with a total production capacity of less than 500 tons per year. All adopt acrolein two-step method synthetic glutaraldehyde (patent open clear 59-108734) on the industry now, because this method exists the raw material source expensive, operating conditions is harsh, the shortcoming such as equipment investment is big and pollution is serious, so scientists are devoted to always for the development of novel synthetic routes to glutaraldehyde. The preparation of glutaraldehyde by oxidative ring-opening of cyclopentene is considered to be a promising route, because the main raw material cyclopentene comes from the by-product of petroleum refining, which has abundant sources and low price. Since the 1980s, existing patent reports include molybdenum cycloacetylacetonate (or molybdenum carbonyl)-dimethyl phosphite system (JP-A-62-29546), copper acetylacetonate/B ₂ O ₃ -phosphoric acid Tributyl ester system (JP-A-62-19548), tungsten trioxide/B ₂ O ₃ -butyl acetate system (Chem.Lett., 1988, 877), phosphomolybdic acid/arsenous acid-tributyl phosphate system (JP-A-57-07434), phosphomolybdenum-tungsten mixed heteropolyacid-phosphoester tributyl ester system (Chem. Lett., 1982, 1951). These catalysts are very sensitive to water, need to be operated in anhydrous system, and the yield of glutaraldehyde is not high (below 50%). And because it involves anhydrous hydrogen peroxide, the operation is extremely dangerous and basically has no industrial value. The homogeneous tungstic acid catalyst reported by Jiang Anren et al. obtained the results of cyclopentene conversion rate of 100% and glutaraldehyde yield > 70% (ZL 89 1 09401.6), but due to the difficulty in separating the catalyst from the product, there is still A certain difficulty. SBA-15 (J.Am.Chem.Soc., 1998 (120), 6024) is a new type of mesoporous SiO ₂ material, which has a larger pore size and thicker pore wall than general mesoporous molecular sieves, showing Better stability makes it have great application potential in heterogeneous fields such as heterogeneous catalysis, adsorption separation and material science.

Contents of the invention

The object of the present invention is to propose a tungsten-containing mesoporous molecular sieve catalyst for the heterogeneous catalytic oxidation of cyclopentene to synthesize glutaraldehyde, which has high catalytic activity, good selectivity to glutaraldehyde, and is convenient for production control, and a preparation method thereof.

The tungsten-containing mesoporous molecular sieve catalyst proposed by the present invention for the heterogeneous catalytic oxidation of cyclopentene to synthesize glutaraldehyde is prepared by introducing _WO3 active components in situ during the synthesis of mesoporous molecular sieve SBA-15, denoted as W - SBA-15, wherein the molar ratio of SiO ₂ and WO ₃ is generally in the range of 5.8 to 73.4.

The above-mentioned tungsten-containing mesoporous molecular sieve catalyst is prepared by an in-situ synthesis method. The specific steps are as follows: dissolve template triblock polymer P123 (ie EO ₂₀ PO ₇₀ EO ₂₀ , referred to as P123) in hydrochloric acid aqueous solution, stir, then add ethyl orthosilicate, and continue stirring to make ethyl orthosilicate Partially hydrolyze the ester, drop into the aqueous solution containing tungsten source, continue to stir for 20-30 hours to make it gel, move the obtained colloid into a high-pressure reactor, and crystallize at 80-200°C for 24-108 hours; take it out, Filtration, washing, calcination to remove the template agent, granulation to obtain the finished catalyst.

In the above-mentioned preparation method, the consumption of template agent P123 is 1-5% of the weight of ethyl orthosilicate, preferably 1-3%; the consumption of above-mentioned hydrolysis agent hydrochloric acid is 1-5 times of the weight of ethyl orthosilicate, Preferably 1-3 times; the amount of water added to the hydrochloric acid is 5-20 times, preferably 8-16 times, the weight of tetraethyl orthosilicate.

In the above preparation method, the tungsten source can be one of phosphotungstic acid, sodium tungstate, and ammonium tungstate, and the preferred tungsten source is sodium tungstate. According to the dosage, it can be prepared into dilute aqueous solution for use. The time for adding the aqueous solution of sodium tungstate is generally 1 to 12 hours after the hydrolysis of ethyl orthosilicate begins, and the better time is 3 to 6 hours. The gelling temperature of the system is 10-100°C, and the preferred gelling temperature is 30-80°C. The gelling process requires stirring (electromagnetic stirring or mechanical stirring); the crystallization temperature is generally 80-200°C, the better crystallization temperature is 90-140°C, and the crystallization time is generally 24-108 hours, and the better time is 50-90 hours. The drying temperature for solids is generally 80-120°C, and the better drying temperature is 90-100°C. After drying, the residual moisture and templating agent need to be further removed. The removal method adopts temperature-programmed roasting. The atmosphere for firing is generally air, oxygen, nitrogen or argon, preferably air or oxygen. The calcination temperature is generally 300-1200°C, and the better temperature range is 400-1000°C. The calcined catalyst can be ground into particles of various sizes as required and activated for later use. The preferred range of particle size is 20-60 mesh, and the preferred range of activation temperature is 300-800°C.

Electron micrographs of typical W-SBA-15 catalysts are shown in Figures 1 and 2.

The activity of the catalyst proposed by the present invention can be tested as follows:

The cyclopentene catalytic oxidation reaction in the present invention is carried out in a sealed round-bottomed flask, using electromagnetic stirring. The reaction conditions are: 30～45℃ oil bath, add 50% or 30% hydrogen peroxide aqueous solution containing 0.5～0.8mol H ₂ O ₂ into 140mL tert-butanol solvent, then add 2.3g catalyst and 0.2～0.4mol ring Pentene, stirred and reacted for 12~60h. After the reaction, the conversion rate of cyclopentene and the selectivity of glutaraldehyde were measured by gas chromatography, and the components were identified by chromatography-mass spectrometry.

The present invention introduces tungsten into the molecular sieve skeleton by adopting the method of in-situ synthesis, which greatly improves the dispersing ability of the molecular sieve to tungstic acid, and improves the effect of the tungsten source and the molecular sieve skeleton. It shows excellent catalytic performance in the reaction of aldehydes, and its selectivity to glutaraldehyde is much higher than that of all catalysts that have been disclosed. The new tungsten-containing SBA-15 mesoporous molecular sieve catalyst shows a good application prospect for the catalytic oxidation of cyclopentene to glutaraldehyde.

The advantage of catalyst provided by the invention is specifically as follows:

1. The catalyst well maintains the unique bamboo-shaped morphology and mesoporous properties of mesoporous molecular sieve SBA-15 while introducing tungsten source.

2. The tungsten species of the catalyst are uniformly dispersed and the dispersion amount is large.

3. The catalyst has high activity, the conversion rate to cyclopentene is over 94%, the selectivity to glutaraldehyde is over 84%, and the yield of glutaraldehyde reaches 80%, showing excellent catalytic performance.

4. The catalyst is insensitive to reaction parameters, has a wide operating range and high flexibility, and is convenient for production control.

5. The tungsten on the catalyst is firmly combined with the carrier, and it has not been found to fall off the surface of the carrier after dozens of experimental cycles.

6. The catalyst is simple to prepare, high in strength, wear-resistant, reusable, and has good catalytic performance after regeneration.

Description of drawings

Figure 1 is a scanning electron micrograph of the W-SBA-15 catalyst.

Figure 2 is a transmission electron micrograph of the W-SBA-15 catalyst.

Detailed ways

The present invention is further described below by way of examples.

Example 1: 40°C oil bath, electromagnetic stirring, 60 mL of concentrated hydrochloric acid was added into 312 mL of deionized water containing 0.3 g of template agent P123 (molecular weight: 5800), and stirred for 4 hours. Add 25.6 g of ethyl orthosilicate, stir for 1 hour, add 10 mL of aqueous solution containing 0.495 g of phosphotungstic acid, and continue stirring for 24 hours. Transfer the obtained colloid into a 1000mL autoclave and seal it, and take it out after crystallization at 100°C for 72 hours; filter, wash with water, and bake at 100°C for 24 hours. Calcined in an oxygen atmosphere at 700°C for more than 6 hours, granulated, sieved with 40-60 meshes, and activated at 800°C for 3 hours to obtain catalyst #1.

Example 2: In an oil bath at 35°C, with mechanical stirring, 90 mL of concentrated hydrochloric acid was added into 468 mL of deionized water containing 0.5 g of template agent P123 (molecular weight: 5800), and stirred for 6 hours. Add 25.6g ethyl orthosilicate, stir for 2 hours, add 10mL aqueous solution containing 1.05g ammonium tungstate, and continue stirring for 36 hours. Transfer the obtained colloid into a 1000mL autoclave and seal it, and take it out after crystallization at 100°C for 48 hours; the remainder is the same as in Example 1 to obtain 2# catalyst.

Example 3: 50° C. oil bath, electromagnetic stirring, 45 mL of concentrated hydrochloric acid was added into 208 mL of deionized water containing 0.4 g of template agent P123 (molecular weight: 5800), and stirred for 3 hours. Add 25.6g ethyl orthosilicate, stir for 1.5 hours, add 10mL aqueous solution containing 2.15g sodium tungstate, and continue stirring for 48 hours. Transfer the obtained colloid into a 500mL autoclave and seal it, and take it out after crystallization at 100°C for 96 hours; the remainder is the same as in Example 1 to obtain 3# catalyst.

Example 4: In an oil bath at 30°C, with mechanical stirring, 60 mL of concentrated hydrochloric acid was added into 624 mL of deionized water containing 1.0 g of template agent P123 (molecular weight: 5800), and stirred for 5 hours. Add 25.6g ethyl orthosilicate, stir for 3 hours, add 10mL aqueous solution containing 3.25g sodium tungstate, and continue stirring for 32 hours. Transfer the obtained colloid into a 1000mL autoclave and seal it, and take it out after crystallization at 100°C for 108 hours; the remainder is the same as in Example 1 to obtain 4# catalyst.

Example 5: 60° C. oil bath, electromagnetic stirring, 100 mL of concentrated hydrochloric acid was added into 780 mL of deionized water containing 0.8 g of template agent P123 (molecular weight: 5800), and stirred for 3 hours. Add 25.6g ethyl orthosilicate, stir for 2 hours, add 10mL aqueous solution containing 4.35g sodium tungstate, and continue stirring for 48 hours. Transfer the obtained colloid into a 2000mL autoclave and seal it, and take it out after crystallization at 130°C for 96 hours; the remainder is the same as in Example 1 to obtain 5# catalyst.

The five catalysts of Examples 1 to 5 were tested for activity, and the results are listed in Attached Table 1.

Attached Table 1. Activity Test Results of Mesoporous Molecular Sieve Catalysts Containing Tungstic Acid catalyst Cyclopentene conversion (wt%) Glutaraldehyde selectivity (wt%) Glutaraldehyde yield (wt%) 1# 80 80.6 64.5 2# 86 82.5 70.9 3# 94 83.9 78.9 4# 70 77.6 54.3 5# 65 72.3 47.0

Claims (9)

1. A tungsten-containing mesoporous molecular sieve catalyst for the heterogeneous catalytic oxidation of cyclopentene to synthesize glutaraldehyde, which is characterized in that it is prepared after in-situ introduction of _WO3 active components during the synthesis of SBA-15 mesoporous molecular sieves, Wherein, the molar ratio of SiO ₂ to WO ₃ is 5.8-73.4. 2. A method for preparing a catalyst as claimed in claim 1, characterized in that the specific steps are: dissolving template agent tri-block polymer P123 in hydrochloric acid aqueous solution, stirring, then adding ethyl orthosilicate, and continuing to stir , so that tetraethyl orthosilicate is partially hydrolyzed, drop into the aqueous solution containing tungsten source, continue to stir for 20-30 hours to make it into a gel, move the obtained colloid into a high-pressure reactor, and crystallize at a temperature of 80-200 ° C for 24 ~108 hours; take out, filter, wash, roast to remove the template agent, and granulate to obtain the finished catalyst. 3. The preparation method of the catalyst according to claim 2, characterized in that the amount of template agent P123 used in the synthesis process is 1-5% of the weight of ethyl orthosilicate. 4. The preparation method of the catalyst according to claim 2, characterized in that the amount of hydrolysis agent hydrochloric acid used in the synthesis process is 1 to 5 times the weight of ethyl orthosilicate. 5. The preparation method of the catalyst according to claim 2, characterized in that the amount of water used to dilute the hydrochloric acid in the synthesis process is 5-20 times the weight of tetraethyl orthosilicate. 6. The catalyst preparation method according to claim 2, characterized in that the tungsten source is one of phosphotungstic acid, sodium tungstate, and ammonium tungstate. 7. The preparation method of the catalyst according to claim 2, characterized in that the hydrolysis time of ethyl orthosilicate is 1-12 hours. 8. The preparation method of the catalyst according to claim 2, characterized in that the gelling temperature of the catalyst is 10-100°C. 9. The preparation method of the catalyst according to claim 2, characterized in that the calcination temperature of the template removal agent for the catalyst is 300-1200°C.