NHPI-GPTMS-CoOX/SiO2 heterogeneous catalyst, applications and recovery method thereof

A heterogeneous catalyst and co-precipitation technology, applied in the field of heterogeneous catalysts, can solve problems such as poor stability and easy loss of NHPI, and achieve the effects of good stability, low equipment requirements, and cost reduction

Inactive Publication Date: 2019-09-03
YANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The impregnation method is simple to operate, and the activity of the prepared heterogeneous catalyst is equivalent to that of homogeneous NHPI, but NHPI is easy to lose during the reaction and has poor stability

Method used

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  • NHPI-GPTMS-CoOX/SiO2 heterogeneous catalyst, applications and recovery method thereof
  • NHPI-GPTMS-CoOX/SiO2 heterogeneous catalyst, applications and recovery method thereof
  • NHPI-GPTMS-CoOX/SiO2 heterogeneous catalyst, applications and recovery method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] first press as figure 1 The procedure shown for the preparation of the heterogeneous catalyst NHPI-GPTMS-CoO X / SiO 2 , the preparation steps are:

[0042] a) Weigh 2.91 g Co(NO 3 ) 2 ·6H 2 O and 2.84 g Na 2 SiO 3 9H 2 O was dissolved in 30 mL of deionized water, and added dropwise to 40 mL of deionized water, and stirred at 363 K for 0.5 h. Placed in a 363 K oven for 24 h. Filter and wash the filter cake repeatedly with deionized water; add 40 mL of n-butanol, mix well with the solid, and evaporate the n-butanol to dryness at 353 K; 3 h, CoO was obtained after grinding X / SiO 2 . like figure 2 CoO shown in A X / SiO 2 Infrared spectrum (A), high-resolution transmission electron microscopy (B) and cobalt element distribution map (C), CoO X / SiO 2 Infrared spectra of cobalt and silica supports form Si—O—Co bonds (1016 cm -1 ), figure 2 The high-resolution TEM image shown in B shows that CoO X / SiO 2 There are no obvious crystal morphology features ...

Embodiment 2

[0048] In this implementation, at first the solid-phase NHPI-GPTMS-CoO obtained after preparing benzaldehyde in Example 1 X / SiO 2 The recovered mixture of heterogeneous catalysts was separated, recovered and purified as follows: wash with a mixed solvent of diethyl ether and chloroform at a volume ratio of 1:1, and dry at 323 K for 24 h to obtain a recycled catalyst NHPI-GPTMS-CoO X / SiO 2 -R 1 .

[0049] The catalyst NHPI-GPTMS-CoO is recovered by this primary cycle X / SiO 2 -R 1 Prepare benzaldehyde by the method of embodiment 1, weigh 0.2 g NHPI-GPTMS-CoO X / SiO 2 -R 1 Place in a 50 mL polytetrafluoroethylene-lined autoclave, add 2 mmol of raw material toluene, and 40 mmol of solvent hexafluoroisopropanol, at a reaction temperature of 363 K, a magnetic stirring speed of 240 r / min and React for 5 h under the condition of oxygen pressure of 2.0 MPa. After the reaction, cool to room temperature and centrifuge to separate the solid and liquid phases. The liquid phase ...

Embodiment 3

[0051] In this example, the solid phase obtained after preparing benzaldehyde in Example 2 is NHPI-GPTMS-CoO X / SiO 2 -R 1 The recovery mixture of heterogeneous catalyst obtains the catalyst NHPI-GPTMS-CoO of secondary recovery by the separation recovery purification method of embodiment 2 X / SiO 2 -R 2 .

[0052] Then by the method of embodiment 2 with NHPI-GPTMS-CoO X / SiO 2 -R 2 To prepare benzaldehyde as a catalyst, the liquid phase reaction product was analyzed for benzaldehyde activity as shown in Table 1. The solid phase recovery mixture is used for the separation, recovery, purification and recycling of the next cycle.

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Abstract

The invention relates to a NHPI-GPTMS-CoOX / SiO2 heterogeneous catalyst, applications and a recovery method thereof, and belongs to the technical field of heterogeneous catalysts, wherein Co<2+>-containing CoOX / SiO2 is prepared by using a co-precipitation method, and then NHPI is immobilized on the CoOX / SiO2 through a covalent bond grafting method to prepare the NHPI-GPTMS-CoOX / SiO2 catalyst. According to the present invention, the cobalt in the NHPI-GPTMS-CoOX / SiO2 has good dispersibility, and forms the Si-O-Co bond with the carrier SiO2, the cobalt content is basically unchanged during the catalyst preparation and the catalytic toluene oxidation reaction, and the leaching phenomenon is not observed; the NHPI is grafted with the silane coupling agent KH-560 (GPTMS) through the C-O-N bond,and the GPTMS is bonded to the carrier through the Si-O-Si bond; when the catalyst is recycled, the graft bond of the NHPI does not break, such that the significant loss of the NHPI cannot be generated; and in the selective oxidation of toluene with hexafluoroisopropanol as solvent, the catalyst has good catalytic activity, good selectivity and good stability.

Description

technical field [0001] The invention relates to the technical field of heterogeneous catalysts, in particular to a kind of NHPI and its initiator Co 2+ Co-immobilized NHPI-GPTMS-CoO X / SiO 2 Heterogeneous catalyst and its application and recovery method in the selective oxidation of toluene to liquid-phase molecular oxygen to benzaldehyde. Background technique [0002] Benzaldehyde is an important intermediate in the fields of spices, dyes, and medicine. There are two main industrial sources of benzaldehyde: as a by-product of the liquid-phase oxidation of toluene to produce benzoic acid and as a by-product of benzyl chloride hydrolysis. The main problem of the former is that the degree of oxidation is difficult to control and the selectivity of benzaldehyde is low; the process of the latter is cumbersome, and the toxic and harmful reagent Cl 2 , Products containing chlorine elements cannot be used in food and pharmaceutical fields. [0003] In recent years, with the in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J31/28C07C45/36C07C47/54
CPCB01J31/28B01J2231/70C07C45/36C07C47/54Y02P20/584
Inventor 石国军徐进杨徐思浩梁雨欣
Owner YANGZHOU UNIV
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