阅读说明：本技术 一种双（1-辛氧基-2,2,6,6-四甲基-4-哌啶基）癸二酸酯的制备方法 (Preparation method of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate ) 是由 王梓 范小鹏 孙春光 张会京 李海平 于 2019-11-13 设计创作，主要内容包括：本发明提供一种光稳定剂双(1-辛氧基-2,2,6,6-四甲基-4-哌啶基)癸二酸酯的制备方法,该方法是在负载型钼催化剂和氧化剂作用下,使双(2,2,6,6-四甲基-4-哌啶基)癸二酸酯与正辛烷反应。本发明的有益效果是减少反应液中影响产品品质的氧化性物质残留,避免了以往工艺中后处理复杂的情况,同时,催化剂可回收重复利用,解决了催化剂寿命问题,利于工业生产。(The invention provides a preparation method of light stabilizer bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, which comprises the step of reacting bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate with n-octane under the action of a supported molybdenum catalyst and an oxidant. The method has the advantages of reducing the residue of oxidizing substances which influence the product quality in the reaction liquid, avoiding the situation of complex post-treatment in the prior art, simultaneously recycling the catalyst, solving the problem of the service life of the catalyst and being beneficial to industrial production.)

1. A preparation method of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate is characterized by comprising the following steps: under the action of a supported molybdenum catalyst and an oxidant, bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate reacts with n-octane, and the reaction formula is as follows:

2. the method of claim 1, wherein: the supported molybdenum catalyst is prepared by adopting an impregnation method, the carrier is selected from activated carbon or diatomite, and the molybdenum source is molybdate or organic molybdenum;

preferably, the molybdate is selected from at least one of ammonium molybdate, sodium molybdate, potassium molybdate, magnesium molybdate, cobalt molybdate, nickel molybdate, manganese molybdate and iron molybdate; the organic molybdenum is selected from at least one of molybdenum hexacarbonyl, molybdenum alkyl acid and molybdenum alkyl salicylate.

3. The method according to claim 1 or 2, characterized in that: the supported molybdenum catalyst is prepared by the following method:

1) dispersing a support and a molybdenum source in a solvent;

2) filtering the solution obtained in the step 1), taking a filter cake, putting the filter cake into a pyrolysis device, and pyrolyzing the filter cake under the protection of inert gas to obtain the filter cake;

preferably, when the molybdenum source is molybdate, water is used as a solvent in the step 1), and when the molybdenum source is organic molybdenum, an organic solvent is used as a solvent in the step 1); further, the organic solvent is at least one selected from toluene and xylene.

4. The method of claim 3, wherein: in the step 2), the pyrolysis temperature is 200-800 ℃, and preferably 400-600 ℃.

5. The method according to claim 3 or 4, characterized in that: the mass ratio of the carrier to the molybdenum source is 1: 0.01-10, preferably 1: 0.1-1.

6. The method of claim 1, wherein: the oxidant is at least one selected from tert-butyl hydroperoxide and hydrogen peroxide, and is preferably tert-butyl hydroperoxide.

7. The method according to claim 1 or 2, characterized in that: the molar ratio of bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate to n-octane is 1: 10-40, preferably 1: 15-30; and/or

The molar ratio of the bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate to the oxidant is 1: 5-9, and preferably 1: 6-7.

8. The method according to claim 1 or 2, characterized in that: the reaction temperature of the bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate and the normal octane is 90-125 ℃.

9. A method according to claim 1 or 2 or 3, characterized in that: the dosage of the supported molybdenum catalyst is 0.1-5%, preferably 2-4% of that of bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate.

10. A method according to claim 1 or 2 or 3, characterized in that: the catalyst can be recycled.

Technical Field

The invention relates to the field of high polymer material functional additives, in particular to a hindered amine light stabilizer, and more particularly relates to a preparation method of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate.

Background

The bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate belongs to alkoxy hindered amine light stabilizers, and the chemical structure is shown as follows.

The hindered amine light stabilizer is a high-efficiency anti-aging auxiliary agent with 2,2,6, 6-tetramethyl piperidine group. The earliest industrialized variety of the light stabilizer is LS-744 developed by Mitsubishi company in 1973, and Ciba-Geigy company in Switzerland also synthesizes the same product in 1974. In recent years, research and development of such light stabilizers and research on application techniques have been rapidly advanced. The varieties which are mainly applied in the market at present are 770, 944, 622 and the like. The light stabilizer 770 is bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, which has better synergistic effect after being used together with an antioxidant and an ultraviolet absorbent. However, the tetramethyl piperidine group in the structure belongs to a secondary amine structure and has stronger alkalinity, so that the hindered amine light stabilizer cannot be applied to an acidic environment and cannot be compounded with an acidic auxiliary agent for use. Based on this, Ciba-Geigy modified 770 structure, which is greatly reduced in basicity by modification of alkoxylation, to about one ten-thousandth of its parent light stabilizer 770. The improved product has obvious application effect, is suitable for polypropylene, high-density polyethylene, polyurethane, polystyrene, ABS resin and the like, and is especially effective in alkyd resin coatings.

Patent CN1823042B from Ciba company reports a process for preparing bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate by using bis (1-oxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate and n-octane as raw materials, aqueous hydrogen peroxide as an oxidant, supplementing ferric chloride hexahydrate and glacial acetic acid for many times for catalysis, and using acetonitrile as a cosolvent, and finally destroying excess peroxide under the action of aqueous sodium sulfite. The method needs to add ferric trichloride and glacial acetic acid for three times, and needs a reducing agent for post-treatment, so that the method has the problems of inconvenient operation and unfavorable industrial production.

Patent CN101570507A reports a process using bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate as a raw material instead of an intermediate containing an oxygen group, wherein the raw material is a commercial light stabilizer 770, which is easy to obtain, and the process route is simplified. However, the patent does not report which catalyst is used, and because the catalyst is not high in efficiency, a higher limit condition is provided for the molar ratio of the raw materials (preferably, the molar ratio of tert-butyl hydroperoxide to the light stabilizer 770 is 7-10: 1), and in addition, in order to ensure the product quality in the production process, a decolorant is added for assistance, so that the solid waste emission is increased.

Patent CN107573280A reports that bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate and n-nonanal are used as raw materials, hydrogen peroxide is used as an oxidant, copper salt or copper oxide is used as a catalyst to react, after the reaction is finished, a reducing reagent and an alkaline substance are added to react, then deionized water is used for washing, and after the washing is finished, the product is obtained by several times of reduced pressure distillation. The product of the patent has high purity, but reducing substances and alkaline substances are used in the post-treatment, if the alkaline substances are not completely removed, the application performance of the product is affected (the product is used in an acidic environment), and a large amount of wastewater is generated when the alkaline substances in the product are completely washed away. Furthermore, the patent lacks corresponding data support for the description of multiple utilization of catalyst recovery.

Patent CN106699639A reports a "two-step" method for preparing bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, the two steps of reaction respectively use different oxidants, step 1) under the catalysis of magnesium hydroxide or magnesium chloride hexahydrate, bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate is made to generate bis (2, 2,6, 6-tetramethyl-piperidyl) sebacate nitroxide radical; step 2) reacting bis (2, 2,6, 6-tetramethylpiperidyl) sebacate nitroxide free radical with n-octane under the catalysis of molybdenum trioxide to synthesize bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, but in the method, a large amount of oxidizing substances remain, an aqueous solution of sodium sulfite needs to be added to destroy the remaining oxidizing substances, and the product yield is only 64.1%.

In conclusion, the existing preparation method of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate has few research reports, the service life of the catalyst used in the reaction is short, the catalyst cannot be recycled, and in addition, the product quality is low due to oxidizing residues, and the post-treatment process is complex. Therefore, it is necessary to provide a novel process for preparing bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a preparation method of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, which comprises the following steps of reacting bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate with n-octane under the action of a supported molybdenum catalyst and an oxidant, wherein the reaction formula is as follows:

the supported molybdenum catalyst is prepared by adopting an impregnation method, the carrier is selected from activated carbon or diatomite, and the molybdenum source is molybdate or organic molybdenum.

The invention also provides a preparation method of the supported molybdenum catalyst, which comprises the following steps:

1) dispersing a support and a molybdenum source in a solvent;

2) filtering the solution obtained in the step 1), taking a filter cake, putting the filter cake into a pyrolysis device, and pyrolyzing under the protection of inert gas to obtain the catalyst.

Compared with the prior art, the invention mainly has the following positive effects:

1. the invention adopts the supported molybdenum as the catalyst, and the catalyst can promote the decomposition of the residual oxidant (even under the condition of very low oxidant concentration), thereby avoiding the problem of residual or accumulated peroxide in the prior art;

2. the method has convenient post-treatment, the reaction solution is filtered to recover the catalyst, and the target product can be obtained by reduced pressure distillation, thereby avoiding using reducing substances and alkaline substances to treat peroxide and avoiding the generation of three wastes; researches show that the average yield of the finished product of the method can reach 95.4 percent, the average purity of bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate is 95.5 percent, and the Gardner color of the product is as low as 0.9;

3. after the catalyst is separated by filtration, the catalyst is directly recycled and reused for at least 9 times, thereby solving the problem of service life of the reaction catalyst and being beneficial to industrial production.

Detailed Description

In the present invention, anything or matters not mentioned is directly applicable to those known in the art without any change except those explicitly described. Moreover, any embodiment described herein may be freely combined with one or more other embodiments described herein, and the technical solutions or ideas thus formed are considered part of the original disclosure or original description of the present invention, and should not be considered as new matters not disclosed or contemplated herein, unless a person skilled in the art would consider such combination to be clearly unreasonable.

All features disclosed in this invention may be combined in any combination and such combinations are understood to be disclosed or described herein unless a person skilled in the art would consider such combinations to be clearly unreasonable.

The numerical points disclosed in the present specification include not only the numerical points specifically disclosed in the examples but also the endpoints of each numerical range in the specification, and ranges in which any combination of the numerical points is disclosed or recited should be considered as ranges of the present invention.

Technical and scientific terms used herein are to be defined only in accordance with their definitions, and are to be understood as having ordinary meanings in the art without any definitions.

In the present invention, the inert gas means a gas having no adverse effect on the performance of the catalyst.

A method for preparing bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, which comprises the following step of reacting bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate with n-octane under the action of a supported molybdenum catalyst and an oxidant, wherein the reaction formula is as follows:

the supported molybdenum catalyst is adopted to prepare the bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, the catalyst can promote the decomposition of residual oxidant, even under the condition of very low oxidant concentration, the decomposition of the residual oxidant can be promoted, further, the residue of oxidizing substances influencing the product quality in a reaction liquid is reduced, the condition of complex post-treatment in the prior art is avoided, the product purity is high, and the yield is high.

The supported molybdenum catalyst is prepared by adopting an impregnation method, and specifically, the supported molybdenum catalyst is prepared by dispersing and mixing a carrier and a molybdenum source and then pyrolyzing the mixture at a high temperature under the protection of inert gas.

Preferably, the support is selected from activated carbon or diatomaceous earth. More preferably, the specification of the activated carbon or the diatomite is 100-400 meshes, and still more preferably, the specification of the activated carbon or the diatomite is 200 meshes.

Preferably, the molybdenum source is a molybdate or an organo-molybdenum. Further preferably, the molybdate is at least one selected from ammonium molybdate, sodium molybdate, potassium molybdate, magnesium molybdate, cobalt molybdate, nickel molybdate, manganese molybdate and iron molybdate; the organic molybdenum is selected from at least one of molybdenum hexacarbonyl, molybdenum alkyl acid and molybdenum alkyl salicylate.

The invention provides a preparation method of the supported molybdenum catalyst, which comprises the following steps:

1) dispersing a support and a molybdenum source in a solvent;

2) filtering the solution obtained in the step 1), taking a filter cake, putting the filter cake into a pyrolysis device, and pyrolyzing under the protection of inert gas to obtain the catalyst.

When the molybdenum source is molybdate, the water is used as a solvent in the step 1), and when the molybdenum source is organic molybdenum, the organic solvent is used as a solvent in the step 1). Preferably, the organic solvent is selected from at least one of toluene and xylene.

Preferably, the mass ratio of the carrier to the molybdenum source is 1 to (0.01-10), and preferably 1 to (0.1-1).

Preferably, the mass-volume ratio of the carrier to the solvent is 1 to (25-35) (g/mL).

It has been found that the presence of oxygen during pyrolysis tends to cause pyrolysis of the support, and therefore, the pyrolysis according to the invention is carried out under inert gas. In a particular embodiment, the oxygen in the muffle furnace is replaced with an inert gas (preferably nitrogen) prior to pyrolysis. Further research shows that the carrier attachment is not easy to decompose and attach due to too low pyrolysis temperature, but the decomposition and attachment of the attachment are not accelerated due to too high pyrolysis temperature and/or longer pyrolysis time. The pyrolysis temperature is preferably 200-800 ℃ (more preferably 400-600 ℃), and the pyrolysis time is preferably 3-6 h.

The purpose of using an oxidizing agent in this reaction is to oxidize bis (2, 2,6,6, -tetramethyl-4-piperidyl) sebacate into bis (2, 2,6,6, -tetramethylpiperidyl) sebacate nitroxide radicals and also to oxidize n-octane into octane radicals, thereby facilitating the reaction. The oxidant is selected from one of tert-butyl hydroperoxide and hydrogen peroxide. Tert-butyl hydroperoxide is more preferable. More preferably an aqueous solution of t-butyl hydroperoxide. In one embodiment, a 60-80% strength aqueous solution of t-butyl hydroperoxide may be used.

Preferably, the oxidant is added dropwise in the invention.

Preferably, the molar ratio of the bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate to the oxidant is 1: 5-9. More preferably 1: 6 to 7.

The research shows that the synthesis reaction can be carried out under normal pressure or under pressure, the reaction temperature under normal pressure is preferably 90-125 ℃, and the temperature of the pressure reaction is 125-150 ℃. The normal pressure reaction is convenient to operate and has low cost. Although the high-temperature pressurization reaction is helpful for improving the reaction efficiency, oxygen is generated in the reaction process, and meanwhile, the pressurization reaction has great potential safety hazard and is not beneficial to industrial production. Therefore, the present application preferably employs a normal pressure method.

Preferably, the molar ratio of the bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate to the n-octane is 1: 10-40. More preferably, 1: (15-30).

Preferably, the dosage of the supported molybdenum catalyst is 0.1-5%, preferably 2-4% of that of bis (2, 2,6, 6-tetramethyl-4-piperidyl) sebacate.

After the reaction is finished, the catalyst can be directly filtered for recycling.

The present invention is described in detail below with reference to specific embodiments, but it should be understood that the scope of the present invention is not limited by these specific embodiments, but is defined by the claims.