CN111701619A

CN111701619A - Immobilized catalyst for synthesizing KH-560 silane coupling agent and preparation method thereof

Info

Publication number: CN111701619A
Application number: CN202010182730.3A
Authority: CN
Inventors: 陈超; 梁秋鸿; 史顺利; 赵丹; 汪淑华; 张宁
Original assignee: Nanchang University
Current assignee: Nanchang University
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-09-25
Anticipated expiration: 2040-03-16
Also published as: CN111701619B

Abstract

The invention discloses an immobilized catalyst for synthesizing a KH-560 silane coupling agent and a preparation method thereof, wherein the immobilized catalyst comprises the following steps: s1, modifying a multidentate N/O hybrid ligand in an MOFs pore channel by taking amino-functionalized MOFs as a substrate through Schiff base reaction or amidation reaction to obtain the MOFs modified by the ligand with the bidentate function; s2, immersing the post-modified MOFs powder into a specific solvent, adding an auxiliary ligand and an acid-binding agent, and stirring and refluxing; slowly dripping a certain amount of chloroplatinic acid methanol solution, continuously refluxing, centrifuging the product obtained after refluxing, and drying in vacuum to obtain the Pt/MOFs catalyst. The immobilized Pt/MOFs catalyst has high catalytic activity, can be recycled repeatedly, and solves the problems of difficult separation of the catalyst and environmental protection brought by reaction waste liquid in the existing preparation method.

Description

Immobilized catalyst for synthesizing KH-560 silane coupling agent and preparation method thereof

Technical Field

The invention relates to the technical field of catalyst preparation, in particular to an immobilized catalyst for synthesizing a KH-560 silane coupling agent and a preparation method thereof.

Background

KH-560 is one of the main species of silane coupling agents (chemical name: gamma-glycidoxypropyltrimethylsilane, corresponding to the trade name: KH-560 (Zhongkojic) or A-187 (United states Co., Ltd.)) due to the epoxy group and hydrolyzable-OCH₃The group makes it have special crosslinking performance, and is widely applied to the bonding modification of organic high molecular materials or inorganic fillers and the mechanical strength enhancement of composite materials so as to improve the wet electrical insulation performance of integrated circuit materials and printed circuit boards.

KH-560 is synthesized by hydrosilylation with allyl glycidyl ether and trimethoxy silane as raw materials under the action of catalyst. For example, in the synthesis of KH-560 by using chloroplatinic acid-isopropanol as a catalyst and methanol as a solvent, the yield reaches 90%, as disclosed in U.S. Pat. No. 4,983,981; the Chinese patent 201811616847.7 takes rhodium complex as catalyst and target product as solvent to prepare KH-560, the yield can reach 95% at most; the Chinese patent 201410372177.4 takes ruthenium trichloride complex as a catalyst and toluene as a solvent, and the yield reaches 92-96 percent. Although many schemes in the current industrial production can effectively synthesize KH-560, a catalytic system mainly adopts a homogeneous precious metal catalyst, and although the effect of the homogeneous catalyst is good, the problems that the catalyst is difficult to separate, cannot be recycled, and the pollution of reaction waste liquid is serious exist, so that the further application of the industrial production is severely restricted. Therefore, heterogenization of homogeneous catalysts, i.e., preparation of supported noble metal catalysts, has been receiving increasing attention. For example, the document doi:10.1002/aoc.4874 reports that a platinum metal Schiff base complex is anchored on a mesoporous molecular sieve SBA-15 for catalytic synthesis of KH-560, and the conversion rate reaches 86%; 10.1016/j.jorganchem.2011.02.021, with aminomethoxysilane, the catalyst showed only a 7% (94% to 87%) drop in yield after five cycles with platinum metal anchored on the silica foam; the document doi 10.4028/www.scientific.net/AMR.233-235.1544 uses a platinum/carbon catalyst as a catalyst, although the conversion rate is as high as 97%, the recycling performance is poor.

It can be seen that, although the heterogeneous catalysis can well reduce the usage amount and recovery difficulty of the noble metal catalyst, there are various problems to be solved, such as disordered activated carbon, mesoporous silica or alumina with a small specific surface as the carrier, low catalytic efficiency, low catalytic selectivity, etc.

Disclosure of Invention

The invention aims to provide an immobilized catalyst for synthesizing a KH-560 silane coupling agent and a preparation method thereof, and effectively solves the technical problems of low catalytic efficiency, low circulation efficiency and the like of the existing catalyst.

The technical scheme provided by the invention is as follows:

a preparation method of an immobilized catalyst for synthesizing a KH-560 silane coupling agent comprises the following steps:

s1, modifying a multidentate N/O hybrid ligand in an MOFs pore channel by taking amino-functionalized MOFs as a substrate through Schiff base reaction or amidation reaction to obtain the MOFs modified by the ligand with the bidentate function;

s2, immersing the post-modified MOFs powder into a specific solvent, adding an auxiliary ligand and an acid-binding agent, and stirring and refluxing; slowly dripping a certain amount of chloroplatinic acid methanol solution, continuously refluxing, centrifuging the product obtained after refluxing, and drying in vacuum to obtain the Pt/MOFs catalyst.

In the technical scheme, the MOFs is a crystalline ordered pore channel structure material formed by self-assembling inorganic metal ions and organic functional groups through covalent bonds, the crystalline ordered pore channel structure material not only has a crystal structure similar to a zeolite molecular sieve, but also has a larger specific surface area compared with the molecular sieve, and a pore channel has designability and cuttability, and the material is easier to functionalize, so that the amino functionalized MOFs are selected as a solid substrate or a carrier for efficient selective catalytic reaction.

The invention also provides a preparation method of KH-560, which comprises the following steps:

KH-560 is prepared by using allyl glycidyl ether and trimethoxysilane as raw materials, using Pt/MOFs catalyst prepared by the method for preparing the supported catalyst according to any one of claims 1 to 6 as a catalyst, and simultaneously dropwise adding and stirring the allyl glycidyl ether and the trimethoxysilane.

The invention also provides an immobilized catalyst for synthesizing the KH-560 silane coupling agent, which comprises MOFs and a Pt complex anchored in the pore channels of the MOFs, and the specific structure is as follows:

the immobilized catalyst for synthesizing the KH-560 silane coupling agent and the preparation method thereof provided by the invention are prepared by taking amino functionalized MOFs as a substrate and anchoring a Pt metal complex in a pore channel of the substrate through a chemical bond, and the immobilized Pt/MOFs catalyst has high catalytic activity and can be recycled for multiple times, thereby solving the problems of difficult separation of the catalyst and environmental protection brought by reaction waste liquid in the existing preparation method; meanwhile, the shape selection capability of the MOFs pore canal greatly reduces the isomeric byproducts, thereby greatly improving the production efficiency. In addition, the process route has simple process, can prepare the KH-560 silane coupling agent with stable quality, high yield and relatively low cost, and has larger industrial production potential.

Drawings

The foregoing features, technical features, advantages and embodiments are further described in the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings.

FIG. 1 is a schematic flow chart of the preparation method of the supported catalyst for synthesizing KH-560 silane coupling agent in the invention.

Detailed Description

The essence of the invention is further illustrated below with reference to the figures and examples, but the invention is not limited thereto.

Aiming at the technical problems of low catalytic efficiency, low cycle efficiency and the like of the existing catalyst, the invention provides a brand-new preparation method of an immobilized catalyst for synthesizing a KH-560 silane coupling agent, as shown in figure 1, and in one embodiment, the preparation method comprises the following steps:

s1 takes amino-functionalized MOFs as a substrate, and modifies the multidentate N/O hybrid ligand in the MOFs pore channel through Schiff base reaction or amidation reaction to obtain the MOFs modified by the ligand with bidentate function. Specifically, the amino-functionalized MOFs is MiL-101-NH₂、UiO-66-NH₂Or IRMOF-3; the N/O hybrid ligand is salicylaldehyde or piperazine anhydride.

S2, immersing the post-modified MOFs powder into a specific solvent, adding an auxiliary ligand and an acid-binding agent, and stirring and refluxing; slowly dripping a certain amount of chloroplatinic acid methanol solution, continuously refluxing, centrifuging the product obtained after refluxing, and drying in vacuum to obtain the Pt/MOFs catalyst, wherein the structure is as follows:

specifically, the specific solvent is toluene, THF or methanol; the auxiliary ligand is one or more of acetylacetone, n-butanol or isobutanol; the acid-binding agent is triethanolamine, and the molar ratio of the modified MOFs powder, the chloroplatinic acid, the auxiliary ligand and the acid-binding agent is 1: 0.1-1.0: 0.5-2.0.

Before the schiff base reaction or amidation reaction in step S1, the method further comprises the step of activating the MOFs: soaking MOFs powder in a specific solvent for a certain time, periodically replacing the specific solvent, centrifuging and drying a product obtained after soaking to obtain activated MOFs; particular solvents are toluene, THF or methanol. Specifically, activated MOFs powder and an N/O hybrid ligand are added into a specific solvent, heating and refluxing are carried out for 12 hours to obtain MOFs modified by the ligand with a bidentate function, wherein the feeding molar ratio of the MOFs powder to the N/O hybrid ligand is 1: 1-10, and the molar mass of the MOFs powder is-NH₂And (4) counting groups.

Based on the Pt/MOFs catalyst prepared by the embodiment, the invention also provides a KH-560 preparation method, which comprises the following steps: the method takes allyl glycidyl ether and trimethoxy silane as raw materials, takes the Pt/MOFs catalyst prepared by the method as a catalyst, and synchronously dropwise adds and stirs allylKH-560 is prepared by reacting a glycidylether with trimethoxysilane. In the process, 2bar of nitrogen is filled, the reaction temperature is 80-90 ℃, the reaction time is 2-6h, the molar ratio of allyl glycidyl ether, trimethoxy silane and Pt/MOFs catalyst is 1:1: 0.001-0.005, wherein the molar mass of the MOFs powder is-NH₂And (4) counting groups.

The invention is described in further detail below by way of examples:

example 1:

synthesis of catalyst 1. (1) Weighing MiL-101-NH₂Powder 1mmol (in-NH)₂Radical meter), immersing in 10mL of methanol solution, standing at room temperature for 1d (1 day) after ultrasonic oscillation, centrifuging, pouring off the upper solution, adding fresh methanol solvent, and repeating the process for 3 times (immersing for 3 days, and changing fresh methanol solution every day). Then placing the centrifuged solid powder in a vacuum drying oven for drying for 4 hours to obtain activated MiL-101-NH₂. (2) Activated MIL-101-NH₂Adding the mixture into 20mL of methanol, dropwise adding 2mmol of salicylaldehyde under strong stirring, heating and refluxing for 12h, and then centrifuging and drying the product to obtain the salicylaldehyde-modified MiL-101. (3) Adding the salicylaldehyde modified MiL-101 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, and heating to reflux; slowly dripping 2ml of chloroplatinic acid methanol solution containing 1mmol, refluxing for 4h, and finally, centrifugally drying the obtained solid product to obtain the catalyst 1.

Example 2:

synthesis of catalyst 2. (1) The synthesis procedure was the same as in (1) of example 1. (2) Activated MIL-101-NH₂Adding the mixture into 20mL of methanol, dropwise adding 1mmol of salicylaldehyde under strong stirring, heating and refluxing for 12h, and centrifugally drying a product to obtain the salicylaldehyde-modified MiL-101. (3) The synthesis procedure was the same as in (3) of example 1, to obtain catalyst 2.

Example 3:

synthesis of catalyst 3. (1) The synthesis procedure was the same as in (1) of example 1. (2) Activated MIL-101-NH₂Adding into 20mL methanol, adding dropwise 10mmol salicylaldehyde under strong stirring, heating and refluxing for 12hAnd centrifuging and drying the product to obtain the salicylaldehyde modified MiL-101. (3) The synthesis procedure was the same as in (3) of example 1, to obtain catalyst 3.

Example 4:

synthesis of catalyst 4. (1) The synthesis procedure was the same as in (1) of example 1. (2) The synthesis procedure was the same as in (2) of example 1. (3) Adding the salicylaldehyde modified MiL-101 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of methanol solution containing 0.1mmol of chloroplatinic acid, refluxing for 4h, and finally, centrifugally drying the obtained solid product to obtain a catalyst 4.

Example 5:

synthesis of catalyst 5. (1) The synthesis procedure was the same as in (1) of example 1. (2) The synthesis procedure was the same as in (2) of example 1. (3) Adding the salicylaldehyde modified MiL-101 into 20mL of methanol solvent, adding 2.0mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of chloroplatinic acid methanol solution containing 0.1mmol, refluxing for 4h, and finally, centrifugally drying the obtained solid product to obtain the catalyst 5.

Example 6:

synthesis of catalyst 6. (1) The synthesis procedure was the same as in (1) of example 1. (2) The synthesis procedure was the same as in (2) of example 1. (3) Adding the salicylaldehyde modified MiL-101 into 20mL of methanol solvent, adding 1.0mmol of isobutanol and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of chloroplatinic acid methanol solution containing 0.1mmol, refluxing for 4h, and finally centrifuging and drying the obtained solid product to obtain the catalyst 6.

Example 7:

synthesis of catalyst 7. (1) The synthesis procedure was the same as in (1) of example 1. (2) Activated MIL-101-NH₂Adding the mixture into 20mL of methanol, dropwise adding 2mmol of piperazine anhydride under strong stirring, heating and refluxing for 12h, and centrifugally drying the product to obtain the piperazine carboxylic acid modified MiL-101. (3) Adding piperazine carboxylic acid modified MiL-101 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, and slowly adding dropwiseAnd refluxing 2ml of a 1mmol methanol solution containing chloroplatinic acid for 4 hours, and finally, centrifugally drying the obtained solid product to obtain the catalyst 7.

Example 8:

synthesis of catalyst 8. (1) Weighing UiO-66-NH₂Powder 1mmol (in-NH)₂Radical meter), immersing in 10mL of methanol solution, standing at room temperature for 1d after ultrasonic oscillation, centrifuging, pouring out the upper layer solution, adding fresh methanol solvent, and repeating the process for 3 times. Drying the centrifuged solid powder in a vacuum drying oven for 4h to obtain activated UiO-66-NH₂. (2) Activated UiO-66-NH₂Adding the mixture into 20mL of methanol, dropwise adding 2mmol of salicylaldehyde under strong stirring, heating and refluxing for 12h, and centrifugally drying a product to obtain salicylaldehyde modified UiO-66. (3) Adding salicylaldehyde modified UiO-66 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of methanol solution containing 1mmol of chloroplatinic acid, refluxing for 4h, and finally, centrifugally drying the obtained solid product to obtain the catalyst 8.

Example 9:

synthesis of catalyst 9. (1) The synthesis procedure was the same as in (1) of example 8. (2) Activated UiO-66-NH₂Adding the mixture into 20mL of methanol, dropwise adding 2mmol of piperazine anhydride under strong stirring, heating and refluxing for 12h, and centrifugally drying the product to obtain piperazine carboxylic acid modified UiO-66. (3) Adding piperazine carboxylic acid modified UiO-66 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of methanol solution containing 1mmol of chloroplatinic acid, refluxing for 4h, and finally, centrifugally drying the obtained solid product to obtain a catalyst 9.

Example 10

Synthesis of catalyst 10. (1) Weighing 1mmol (as-NH) of IRMOF-3 crystals₂Radical meter), immersing in 10mL of methanol solution, standing at room temperature for 1d after ultrasonic oscillation, centrifuging, pouring out the upper layer solution, adding fresh methanol solvent, and repeating the process for 3 times. And (3) placing the centrifuged solid powder in a vacuum drying oven for drying for 4h to obtain activated IRMOF-3. (2) Adding activated IRMOF-3 to 20mL of methanol with vigorous stirringDropwise adding 2mmol of salicylaldehyde under stirring, heating and refluxing for 12h, and centrifugally drying the product to obtain salicylaldehyde modified IRMOF-3. (3) Adding salicylaldehyde modified IRMOF-3 into 20mL of methanol solvent, adding 1mmol of acetylacetone and 1mmol of triethanolamine, heating to reflux, slowly dropwise adding 2mL of methanol solution containing 1mmol of chloroplatinic acid, refluxing for 4h, and finally centrifuging and drying the obtained solid product to obtain the catalyst 10.

Example 11

The catalyst catalyzes the synthesis KH-560 test.

8.6L of trimethoxysilane and 7.8 mL of allyl glycidyl ether were added to the autoclave via a pipette, 5 mL of internal dodecane was added, and the mixture was mixed well. Then adding solid catalyst, and sealing. Introducing nitrogen, discharging and discharging air for 3 times, evacuating the air in the reaction kettle, keeping the pressure of the reaction kettle at 2bar, mechanically stirring for 360r/min, setting the temperature at 80-90 ℃, and continuously reacting for 2-6 h. GC qualitative analysis of main reaction product and side product, then distillation under reduced pressure to separate the product, and calculation of KH-560 yield (Table 1).

Example 12

Recovery of catalyst the catalytic test was cycled. The catalyst after the reaction was recovered by centrifugation and recycled for the second and third cycles without washing, and the reaction conditions were the same as those in example 11, and the yield was calculated again (table 1).

TABLE 1 yield of KH-560 catalytically synthesized by different catalysts

Catalyst and process for preparing same	Catalyst 1	Catalyst 2	Catalyst 3	Catalyst 4	Catalyst 5	Catalyst 6	Catalyst 7	Catalyst 8	Catalyst 9	Catalyst 10
											KH-560 yield	85%	74%	78%	56%	68%	55%	82%	75%	74%	86%
KH-560 yielda	83%	74%	78%	54%	66%	54%	81%	73%	74%	45%
											KH-560 yieldb	82%	73%	77%	50%	65%	53%	74%	72%	74%	11%

Wherein the content of the first and second substances,athe recovery rate of the catalyst used for the second time,bthe catalyst was recovered in a third use yield.

As can be seen from the table, even if the catalyst 1 to the catalyst 10 are recycled for the third use, the yield is better.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of an immobilized catalyst for synthesizing a KH-560 silane coupling agent is characterized by comprising the following steps:

2. The method of claim 1, wherein in step S1, the MOFs with amino functionalization is MiL-101-NH₂、UiO-66-NH₂Or IRMOF-3; the N/O hybrid ligand is salicylaldehyde or piperazine anhydride.

3. The production method according to claim 1, wherein in step S2, the specific solvent is toluene, THF, or methanol; the auxiliary ligand is one or more of acetylacetone, n-butanol or isobutanol; the acid-binding agent is triethanolamine.

4. The method of claim 3, wherein in step S2, the molar ratio of the modified MOFs powder to the chloroplatinic acid to the ancillary ligand to the acid-binding agent is 1: 0.1-1.0: 0.5-2.0.

5. The method of claim 1 or 2 or 3 or 4, wherein the schiff base reaction or amidation reaction of step S1 is preceded by the step of activating MOFs:

soaking MOFs powder in a specific solvent for a certain time, periodically replacing the specific solvent, centrifuging and drying a product obtained after soaking to obtain activated MOFs; the specific solvent is toluene, THF or methanol.

6. The production method according to claim 5, characterized by comprising, in step S1:

adding activated MOFs powder and an N/O hybrid ligand into a specific solvent, heating and refluxing for 12h to obtain the MOFs modified by the ligand with the bidentate function, wherein the feeding molar ratio of the MOFs powder to the N/O hybrid ligand is 1: 1-10, and the molar mass of the MOFs powder is-NH₂And (4) counting groups.

7. A preparation method of KH-560, which is characterized by comprising the following steps:

8. The KH-560 preparation method of claim 7, wherein the molar ratio of allyl glycidyl ether, trimethoxysilane and Pt/MOFs catalyst is 1:1: 0.001-0.005, wherein the molar mass of MOFs powder is-NH₂And (4) counting groups.

9. The process of claim 7 or 8, wherein the KH-560 is prepared by introducing 2bar of nitrogen at 80-90 ℃ for 2-6 hours during the catalytic reaction for preparing KH-560.

10. The immobilized catalyst for synthesizing the KH-560 silane coupling agent is characterized by comprising MOFs and a Pt complex anchored in the MOFs pore channels, and the specific structure is as follows: