阅读说明：本技术 一种阻聚剂701的制备方法 (Preparation method of polymerization inhibitor 701 ) 是由 李嫚嫚 蒋小惠 毕景峰 郭颖 王尹卓 于 2020-12-28 设计创作，主要内容包括：本发明公开了一种聚剂701的制备方法,其步骤为：将四甲基哌啶醇和载体催化剂加入到极性溶液中,然后加入过氧化氢,纯化处理得到阻聚剂701。使用该制备方法。本发明中使用的改性载体催化剂,是固体不溶物,易分离,得到的产物产率高；本发明中使用的改性载体催化剂可重复利用,重复利用3次得到的产率均高于97％。(The invention discloses a preparation method of a polymerization agent 701, which comprises the following steps: adding tetramethyl piperidinol and a carrier catalyst into the polar solution, then adding hydrogen peroxide, and purifying to obtain the polymerization inhibitor 701. The preparation method is used. The modified carrier catalyst used in the invention is solid insoluble substance, is easy to separate, and the yield of the obtained product is high; the modified carrier catalyst used in the invention can be recycled, and the yield obtained by recycling 3 times is higher than 97%.)

1. A preparation method of a polymerization inhibitor 701 is characterized by comprising the following steps: adding the tetramethylpiperidinol and the modified carrier catalyst into the polar solution, then adding hydrogen peroxide, and purifying to obtain the polymerization inhibitor 701.

2. The method according to claim 1, wherein the polymerization inhibitor 701 is prepared by: the modified carrier catalyst is prepared by loading phosphotungstic acid on a modified carrier; the modified carrier is prepared by oxidizing a multi-wall carbon nano tube.

3. The method for preparing the polymerization inhibitor 701 according to claim 2, wherein the oxidation step of the modified carrier comprises: and adding the multi-wall carbon nano tube into a ferrous sulfate solution, oxidizing under the condition of hydrogen peroxide, filtering and drying to obtain the modified carrier.

4. The method for preparing a polymerization inhibitor 701 according to claim 2 or 3, wherein the modified supported catalyst is loaded by: and dissolving the phosphotungstic acid in deionized water, then adding the modified carrier, heating and stirring, filtering and drying to obtain the modified carrier catalyst.

5. The preparation method of the polymerization inhibitor 701 according to claim 1, wherein the polymerization inhibitor 701 is synthesized by the following steps: adding tetramethylpiperidinol and a modified carrier catalyst into deionized water, slowly adding hydrogen peroxide, stirring for 0.5-2 hours at 20-40 ℃, filtering, and distilling the obtained filtrate under reduced pressure to obtain the polymerization inhibitor 701.

6. The preparation method of the polymerization inhibitor 701 according to claim 1, wherein the mass ratio of the tetramethylpiperidinol to the modified supported catalyst is 1:0.01 to 0.1; the molar ratio of the tetramethylpiperidinol to the hydrogen peroxide is 1: 1.1-1.5.

Technical Field

The invention relates to the technical field of polymerization inhibitor synthesis, and particularly relates to a preparation method of a polymerization inhibitor 701.

Background

The polymerization inhibitor 701 is also called nitroxide radical piperidinol, has a chemical name of 2,2,6, 6-tetramethyl-4-hydroxypiperidine nitroxide radical (TMHP0), and is a novel and efficient polymerization inhibitor for unsaturated compounds such as olefin monomers, acrylates, methacrylates, acrylic acid, acrylonitrile, styrene, butadiene, vinyl chloride, unsaturated polyesters and the like and pesticides. Its polymerization inhibiting performance is superior to that of polymerization inhibitors of phenols, arylamines, ethers, quinones and nitro compounds, etc., and it can replace hydroquinone with greater environmental pollution, and its polymerization inhibiting effect is about 4 times that of hydroquinone. The method is suitable for preventing olefin and unsaturated monomers from self-polymerization in the processes of production, separation, refining, storage and transportation, and controlling and adjusting the polymerization degree of olefin and derivatives thereof in organic synthesis reaction, and has wide market prospect.

In the traditional process, sodium tungstate or phosphotungstic acid is mainly used as a catalyst, hydrogen peroxide is used as an oxidant, methanol, water and methanol-acetonitrile are used as solvents, and nitroxide radical piperidinol is obtained through oxidation and oxidation of hydrogen. The disadvantages of this method are: the method has the advantages of low yield, long reaction time, severe local heat release, easy generation of by-products, incapability of meeting the requirement on product quality, large catalyst consumption, incapability of effectively separating and recycling, and capability of obtaining products only by adopting a crystallization method, so that a large amount of waste liquid is generated to pollute the environment.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a preparation method of a polymerization inhibitor 701, which has the advantages of easy catalyst separation and high product yield.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention provides a preparation method of a polymerization inhibitor 701, which comprises the following synthetic steps: adding tetramethyl piperidinol and a carrier catalyst into the polar solution, then adding hydrogen peroxide, and purifying to obtain the polymerization inhibitor 701.

The synthetic route of the above reaction is as follows:

further, the modified carrier catalyst is prepared by loading phosphotungstic acid on a modified carrier; the modified carrier is prepared by oxidizing a multi-wall carbon nano tube.

Preferably, the polar solvent is one of deionized water, methanol and ethanol.

Further, the oxidation step of the modified support is: and adding the multi-wall carbon nano tube into a ferrous sulfate solution, oxidizing under the condition of hydrogen peroxide, filtering and drying to obtain the modified carrier.

Further, the modified supported catalyst is loaded by the following steps: and dissolving the phosphotungstic acid in deionized water, then adding the modified carrier, heating and stirring, filtering and drying to obtain the modified carrier catalyst.

Further, the polymerization inhibitor 701 comprises the following specific synthesis steps: adding tetramethylpiperidinol and a modified carrier catalyst into deionized water, slowly adding hydrogen peroxide, stirring for 0.5-2 hours at 20-40 ℃, filtering, and distilling the obtained filtrate under reduced pressure to obtain the polymerization inhibitor 701.

Further, the mass ratio of the tetramethylpiperidinol to the modified supported catalyst is 1: 0.01-0.1; the molar ratio of the tetramethylpiperidinol to the hydrogen peroxide is 1: 1.1-1.5.

Preferably, the mass ratio of the tetramethylpiperidinol to the modified supported catalyst is 1: 0.02.

Compared with the prior art, the invention has the following technical effects:

(1) the method has the advantages of short reaction time, mild reaction conditions, less side reactions and simple operation.

(2) The modified carrier catalyst used in the invention is a solid insoluble catalyst, can be separated by a simple filtration mode and can be recycled, and the catalytic performance of the catalyst is basically unchanged; and the yield of the obtained product is high, and the yield obtained by recycling for 3 times is higher than 97 percent.

Detailed Description

It should be understood that the preferred embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present invention.

Example 1

Preparation of modified Supported catalysts

(1) Preparation of modified carrier: weighing multi-wall carbon nano tubes (10g) and adding the multi-wall carbon nano tubes into a 0.2mol/L ferrous sulfate (100mL) solution, then adding 0.2mol/L dilute sulfuric acid to adjust the pH value of the solution to be 3, then slowly adding 30% hydrogen peroxide (4g) by mass fraction, and stirring for 8 hours at 25 ℃. The reaction solution was filtered, and the resulting solid was washed with deionized water 3 times, and then the solid was placed in an oven and baked at 50 ℃ for 4 hours to obtain oxidized multiwall carbon nanotubes containing hydroxyl groups (9.8 g).

(2) Preparation of modified supported catalyst: phosphotungstic acid (0.2g) was weighed out and dissolved in deionized water (40mL), and the oxidized multiwalled carbon nanotubes (2g) above were added and stirred at 50 ℃ for 5 hours. The reaction solution was filtered, and the obtained solid was washed with deionized water 3 times, and then the solid was placed in an oven and baked at 50 ℃ for 4 hours to obtain a supported catalyst (2 g).

(3) The phosphotungstic acid is colorless, off-white powdery solid or light yellow fine crystal, is easy to dissolve in water, can be loaded into a cavity of the modified carrier, namely the oxidized multi-walled carbon nanotube in the loading process, and can also form a stable hydrogen bond structure with a hydroxyl structure, so that the loading amount of the phosphotungstic acid in the modified carrier is increased, and the stable modified carrier catalyst is formed.

Example 2

(1) Preparation of polymerization inhibitor 701

Tetramethylpiperidinol (50g, 0.318mol) and a modified supported catalyst (1g) were added to deionized water (20g), followed by slowly adding 30% by mass hydrogen peroxide (45g, 0.397mol), and stirring at 25 ℃ for 1 hour. Filtration gave a cake and a filtrate, and the obtained filtrate was distilled under reduced pressure to give polymerization inhibitor 701(53.7g,0.312mol, molar yield 98.0%).

(2) Purification of the modified supported catalyst: the filter cake obtained in example 2 was washed 3 times with deionized water, and then placed in an oven and baked at 50 ℃ for 4 hours to obtain a modified supported catalyst (0.97g) used 1 time.

Examples 3 to 5

The modified supported catalyst used 1 time in example 2 was reused 3 times, and the rest of the reaction conditions were the same as in example 2, to obtain the reaction results of examples 3 to 5, as shown in table 1 below:

TABLE 1 catalyst usage and product yield in examples 3-5

	Number of times of catalyst use	Amount of catalyst (g)	Product yield (g)	Product yield (%)
					Example 3	2	0.97	53.6	97.9
Example 4	3	0.95	53.6	97.9
					Example 5	4	0.94	53.2	97.1

As can be seen from Table 1, the catalyst was used 3 times again, and there was slight loss during the use, but it still had catalytic performance, and the catalytic performance was basically unchanged. The obtained product yield is not very different and is over 97 percent.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.