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Organic-inorganic hybrid hydrotalcite-like heteropoly acid-supported catalyst

A technology for supporting heteropolyacids and heteropolyacid salts, applied in organic compound/hydride/coordination complex catalysts, physical/chemical process catalysts, organic chemistry, etc. Hydrotalcite, catalyst activity and selectivity are not high, ion exchange is difficult to complete, etc., to achieve the effect of improving lipophilic performance, low cost, and no decrease in selectivity

Inactive Publication Date: 2011-05-04
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are only a few examples of the direct co-precipitation method, because most of the heteropolyacids and their salts are only stable under acidic pH conditions, and the alkaline precipitant required for co-precipitation will decompose the heteropolyacids, resulting in a large amount of amorphous The formation of substances, and the loaded heteropolyacid is not completely the original heteropolyacid
The roasting recovery method is to use the "memory effect" of hydrotalcite, first calcining Mg-Al hydrotalcite into mixed metal oxides, and then compounding with pure water to form interlayer OH - meixnerite, and then perform ion exchange with heteropolyacid salt solution. This method is suitable for the intercalation assembly of various heteropolyacid salts. The common disadvantage is that heteropolyacids and laminate cations will generate Amorphous substance, thus blocking interlayer channels
The ion exchange method is divided into two types, one is to use simple inorganic anions (NO 3 - , Cl - ) pillar-supported hydrotalcite as the exchange precursor, this ion exchange is difficult to complete, and will also generate amorphous heteropolyacid salts; the other is based on organic anions (adipate, terephthalate, P-toluenesulfonate, dodecyl sulfate, etc.) pillared hydrotalcites are exchange precursors, and the interlayer channels of this pre-supported precursor are relatively large (>1nm), which is conducive to the ion exchange of heteropolyacid salts , but it is usually not possible to obtain fully exchanged heteropolyacid pillared hydrotalcites
[0010] Hydrotalcite-like supported heteropolyacids have been used in many organic reactions as solid acid catalysts and redox catalysts, but not many applications in the hydrogen peroxide epoxidation of olefins [Appl.Catal.A 167 (1998) 65 ; J.Mol.Catal.A 145(1999) 281], the effect is also very unsatisfactory, mainly because the heteropolyacid of Keggin structure is unstable to hydrogen peroxide, easily degrades, and the activity and selectivity of catalyst are not high in addition
[0011] In summary, no breakthrough has been made in the liquid-phase epoxidation of olefins with hydrotalcite-supported heteropolyacid catalysts. The low activity, selectivity and poor stability of the catalysts are the biggest disadvantages that limit its industrial application.

Method used

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preparation example Construction

[0046] The preparation method of organic-inorganic hybrid hydrotalcite-like loaded heteropolyacid salt comprises the following steps:

[0047] A. According to the molar ratio of divalent metal ions to trivalent metal ions is 2 to 4:1, weigh a certain amount of nitrate or chloride salt of divalent and trivalent metal ions, and make it with freshly boiled deionized water 1~5mol / L mixed salt solution; prepare solid NaOH into 1~10mol / L alkali solution, fill the mixed salt solution and alkali solution into the dropping funnel and place them on the three-necked flask; The molar ratio is 2-5:1, put a certain amount of organic acid salt in the three-necked flask, then add an appropriate amount of freshly boiled deionized water, and keep stirring fully; drop the mixed salt solution and alkali solution into the three-necked flask respectively, Control the drop rate of the salt solution to 1-5ml / min, control the drop rate of the alkali solution to maintain a constant pH, keep the pH cons...

Embodiment 1

[0066] Preparation of Organic-Inorganic Hybrid Hydrotalcites (I)

[0067] 0.03mol Zn(NO 3 ) 2 ·6H 2 O(8.9g) and 0.01mol Al(NO 3 ) 3 9H 2 O (3.75g) is made into 2mol / L mixed salt solution with freshly boiled deionized water; 0.08mol NaOH (3.2g) is made into 4mol / L alkali solution, and the mixed salt solution and alkali solution are respectively filled into the dropping funnel Place on the three-necked flask; put 0.02mol sodium dodecylsulfonate (5.45g) in the three-necked flask, then add 40ml of freshly boiled deionized water, keep stirring fully; drop the mixed salt solution and alkali solution respectively Add into a three-necked flask, control the dropping rate of the salt solution to 2ml / min, and control the dropping rate of the alkali solution to keep the pH constant at 7 until the addition of the mixed salt solution is completed; crystallize the obtained slurry at 90°C for 24 hours, and then pump Filter, wash repeatedly with hot water, take 4.8g of wet filter cake an...

Embodiment 2

[0069] Preparation of Organic-Inorganic Hybrid Hydrotalcites (II)

[0070] 0.015mol Mg(NO 3 ) 2 ·6H 2 O(3.85g), 0.015mol Zn(NO 3 ) 2 ·6H 2 O (4.47g) and 0.01mol Al (NO 3 ) 3 9H 2 O (3.75g) is made into 2mol / L mixed salt solution with freshly boiled deionized water; 0.08mol NaOH (3.2g) is made into 4mol / L alkali solution, and the mixed salt solution and alkali solution are respectively filled into the dropping funnel Place on the three-necked flask; put 0.03mol sodium stearate (9.2g) in the three-necked flask, then add 40ml of freshly boiled deionized water, and keep fully stirring; drop the mixed salt solution and alkali solution into the three-necked flask respectively , the rate of addition of the salt solution is controlled to be 2ml / min, and the rate of addition of the alkaline solution is controlled to keep the pH constant at 9 until the addition of the mixed salt solution is complete; After repeated washing with hot water, 4.5 g of the wet filter cake was dried ...

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Abstract

The invention involves preparation method of organic-inorganic hybridization hydrotalcite load heteropoly acid slat catalyst and its application in hydrogen dioxide epoxidation reaction of liquid phase olefin. The preparation method of catalyst is: synthesizing organic-inorganic hybridization hydrotalcite which interlaminar is organic acid anion, dispersing it with water into slurry again, anion exchanging right amount of slurry and sandwich-type heteropoly acid salt, the amount of heteropoly acid salt is 0.1-2 times of similar hydrotalcite anion exchange capacity; the condition of ion exchange is: stirring 5-120 minutes under 50-100 DEG C and the protect of N2, filtering, washing and drying, then preparing the organic-inorganic hybridization hydrotalcite load heteropoly acid slat catalyst. The catalyst is used for hydrogen dioxide epoxidation reaction of liquid phase olefin, has high catalysis activity and selectivity and can be used cyclically and repeatedly.

Description

technical field [0001] The invention relates to an organic-inorganic hybrid hydrotalcite-like supported heteropolyacid salt catalyst. [0002] The present invention also relates to a method for preparing the above-mentioned catalyst. [0003] The present invention also relates to the application of the above-mentioned catalyst in liquid-phase olefin epoxidation. Background technique [0004] The epoxidation of liquid-phase olefins is an important class of organic reactions, and its epoxy products are very useful synthetic intermediates, widely used in the synthesis of epoxy resins, drugs, natural products, etc. The traditional liquid-phase olefin epoxidation mainly uses organic peroxides and peracids as oxidants, which not only have high cost and many by-products, but also cause a series of problems such as environmental pollution. Therefore, it is inevitable to develop an environmentally friendly green epoxidation system . [0005] Aqueous hydrogen peroxide has received ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J31/02B01J23/00B01J37/02C07D301/12
Inventor 李灿刘鹏
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI