阅读说明：本技术 一种季戊四醇烯丙基醚的制备方法 (Preparation method of pentaerythritol allyl ether ) 是由 张善炯 金一丰 张美军 马夏坤 王马济世 张静 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种季戊四醇烯丙基醚的制备方法,属于有机合成技术领域。该制备方法是以PEP型聚醚为相转移催化剂,将季戊四醇、醇盐化试剂和相转移催化剂投入反应釜中搅拌并缓慢升温,再向反应混合物中缓慢滴加封端剂烯丙基卤化物,保温反应得到季戊四醇烯丙基醚粗品,经水洗并分离水层和有机层,对有机层常压蒸馏除去轻沸物,再减压蒸馏得到季戊四醇烯丙基醚产品。本发明以PEP型聚醚为相转移催化剂,成本低、毒性低,可以抑制副反应的发生,产品收率高,对季戊四醇三烯丙基醚的选择性可达90％以上,操作简单、反应条件温和、生产成本低、易于工业化生产。(The invention discloses a preparation method of pentaerythritol allyl ether, belonging to the technical field of organic synthesis. The preparation method comprises the steps of taking PEP type polyether as a phase transfer catalyst, putting pentaerythritol, an alcohol alkylating agent and the phase transfer catalyst into a reaction kettle, stirring and slowly heating, slowly dropwise adding an end-capping agent allyl halide into a reaction mixture, carrying out heat preservation reaction to obtain a pentaerythritol allyl ether crude product, washing with water, separating a water layer and an organic layer, removing light-boiling substances from the organic layer by atmospheric distillation, and carrying out reduced pressure distillation to obtain the pentaerythritol allyl ether product. The invention takes PEP type polyether as a phase transfer catalyst, has low cost and low toxicity, can inhibit side reaction, has high product yield, has selectivity to pentaerythritol triallyl ether of more than 90 percent, is simple to operate, has mild reaction condition and low production cost, and is easy for industrial production.)

1. A preparation method of pentaerythritol allyl ether is characterized by comprising the following steps: the method comprises the following steps:

s1, adding pentaerythritol, an alcohol salinization reagent and a phase transfer catalyst into a reaction kettle, stirring under normal pressure, and heating to 60-120 ℃; wherein, the phase transfer catalyst is PEP type polyether;

s2, adding an end-capping reagent allyl halide, controlling the reaction temperature in the dropping process, and preserving the temperature after the reaction is finished to obtain a pentaerythritol allyl ether crude product;

s3, washing the pentaerythritol allyl ether crude product obtained in the step S2 with water, distilling at normal pressure and distilling under reduced pressure to obtain the pentaerythritol allyl ether.

2. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the structural formula of the phase transfer catalyst is as follows: R-EOn-POm-EOn-R; wherein R is methyl, ethyl or butyl, and n: m is 1: 1.5-3.

3. The process for producing pentaerythritol allyl ether according to claim 2, characterized in that: the molecular weight of the phase transfer catalyst is 500-2000.

4. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the alcoholization reagent is an alkali metal hydroxide aqueous solution with the mass fraction of 35-55%; wherein the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

5. The method of claim 4, wherein the allyl ether of pentaerythritol is: the molar ratio of the pentaerythritol to the alkali metal hydroxide is 1: 3.2-3.8.

6. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the mass ratio of the pentaerythritol to the phase transfer catalyst is 1: 0.02-0.2.

7. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the allyl halide is methyl chloropropene or methyl bromopropylene.

8. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the molar ratio of the pentaerythritol to the allyl halide is 1: 3.5-4.2.

9. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the reaction temperature in the step S2 is 60-120 ℃, the reaction time is 2-8 h, and the heat preservation time is 2-6 h.

10. The process for producing pentaerythritol allyl ether according to claim 1, characterized in that: the temperature for removing light components by normal pressure distillation in the step S3 is 100-130 ℃; the temperature of the product collected by reduced pressure distillation is 130-160 ℃, and the vacuum degree is less than 20 mbar.

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a preparation method of pentaerythritol allyl ether.

Background

Pentaerythritol allyl ether has active groups such as ether group, olefinic bond and hydroxyl group, and is commonly used as a chain extender for synthesizing polymers such as super absorbent resin, thickening agent, unsaturated polyester, polyurethane resin, epoxy resin and the like, so that the polymers have self-drying property. The industrially commonly used pentaerythritol allyl ether mixture is mainly pentaerythritol triallyl ether, and the mass fraction of the mixture is 70-90%.

The existing method for preparing pentaerythritol allyl ether is mainly based on Williamson synthesis, and in order to ensure that the reaction can be smoothly and rapidly carried out, a phase transfer catalyst is generally added in the reaction process. For example, chinese patent CN100410304C discloses a method for preparing pentaerythritol allyl ether, which comprises feeding allyl chloride, an alkali catalyst and pentaerythritol at a certain molar ratio to react under the action of a phase transfer catalyst, but nitrogen is charged to 0.2MPa during the etherification reaction, and a pressurizing device is used for reaction, so that the method has the disadvantages of large equipment investment, low reaction conversion rate and the like, and is not suitable for industrial production of pentaerythritol allyl ether; in addition, the method takes PEG 200-PEG 1000 as a phase transfer catalyst, and the phase transfer catalyst can participate in the reaction process, and is blocked on the raw material, so that a byproduct is easily generated. Patent publication No. CN101712597A discloses that tetrabutylammonium bromide is used as a phase transfer catalyst, and p-hydroxyanisole is added as a polymerization inhibitor to prepare pentaerythritol allyl ether, but salt washing, alkali washing and water washing steps are required to be respectively carried out after etherification reaction, so that a large amount of waste water is generated, and the requirements of green chemistry are not met. Patent CN101200413B selects several quaternary ammonium salts (tetrabutyl ammonium bromide, tetrabutyl ammonium chloride, hexadecyl tributyl ammonium bromide, benzyl triethyl ammonium chloride and trioctylmethyl ammonium chloride) as phase transfer catalysts, and the catalysts have high cost, can cause pollution to water and are not easy to recover.

Therefore, it is necessary to develop a new method for preparing pentaerythritol allyl ether, which has the advantages of simple operation, mild reaction conditions, low production cost and easy recovery of phase transfer catalyst.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the preparation method of pentaerythritol allyl ether, which takes PEP type end-capped polyether as a phase transfer catalyst, can inhibit side reactions, has high product yield, has selectivity on pentaerythritol triallyl ether of more than 90 percent, is simple to operate, has mild reaction conditions and low production cost, and is easy for industrial production.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a preparation method of pentaerythritol allyl ether comprises the following steps:

s1, adding pentaerythritol, an alcohol salinization reagent and a phase transfer catalyst into a reaction kettle, stirring under normal pressure, and heating to 60-120 ℃; wherein, the phase transfer catalyst is PEP type polyether;

s2, adding an end-capping reagent allyl halide, controlling the reaction temperature in the dropping process, and preserving the temperature after the reaction is finished to obtain a pentaerythritol allyl ether crude product;

s3, washing the pentaerythritol allyl ether crude product obtained in the step S2 with water to dissolve salt generated in the reaction, unreacted alkali metal hydroxide and a phase transfer catalyst, separating a water layer and an organic layer, repeating twice, distilling the organic layer at normal pressure to remove light boiling point substances, and distilling under reduced pressure to obtain the pentaerythritol allyl ether.

The invention adopts PEP type polyether as a phase transfer catalyst, both ends of the PEP type block copolyether are terminated by alkyl, and the PEP type block copolyether as the phase transfer catalyst can not participate in the reaction, thereby not causing the generation of byproducts. In addition, the decomposition temperature of the phase transfer catalyst is far higher than the distillation temperature of the product, the decomposition and inactivation cannot occur in the reaction, and the recovered phase transfer catalyst can be continuously recycled, so the phase transfer catalyst is an ideal phase transfer catalyst for preparing pentaerythritol allyl ether.

The principle of the phase transfer catalytic reaction of the invention is as follows:

1. pentaerythritol reacts with the alcohol alkylating agent to form an intermediate soluble in water:

2. under the action of a phase transfer catalyst, the intermediate enters an organic phase and reacts with allyl halide to generate pentaerythritol triallyl ether:

3. during the reaction, water and the alcoholizing agent undergo side reactions with the allyl halide to yield the allyl alcohol and the allyl ether:

CH₂＝CH₂-CH₂Cl+MOH→CH₂＝CH₂-CH₂OH+MCl

CH₂＝CH₂-CH₂Cl+H₂O→CH₂＝CH₂-CH₂OH+MCl

CH₂＝CH₂-CH₂Cl+CH₂＝CH₂-CH₂OH→CH₂＝CH₂-CH₂OCH₂-CH₂＝CH₂+HCl

therefore, the phase transfer catalyst added during the reaction can transfer the intermediate and allyl chloride to the organic phase, and can greatly inhibit the occurrence of side reactions.

The structural formula of pentaerythritol triallyl ether is as follows:

in addition, since monohydroxy substituents of polyhydric alcohols are easily formed, when a product containing a large amount of pentaerythritol triallyl ether is produced, the reaction may be carried out by using an excess amount of allyl halide and an alkoxide.

As a preferred embodiment of the present invention, the structural formula of the phase transfer catalyst is: R-EOn-POm-EOn-R; wherein R is methyl (-CH)₃) Ethyl (-CH)₂CH₃) Or butyl (- (CH) - (CH))₂)₃CH₃) And n is 1: 1.5-3.

In a preferred embodiment of the present invention, the molecular weight of the phase transfer catalyst is 500 to 2000.

In a preferred embodiment of the invention, the alcoholizing agent is an aqueous solution of alkali metal hydroxide with a mass fraction of 35% to 55%; among them, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide, and sodium hydroxide is preferable.

In a preferred embodiment of the present invention, the molar ratio of pentaerythritol to alkali metal hydroxide is 1:3.2 to 3.8.

In a preferred embodiment of the present invention, the mass ratio of pentaerythritol to the phase transfer catalyst is 1:0.02 to 0.2.

As a preferred embodiment of the present invention, the allyl halide is methyl chloropropene or methyl bromopropylene.

In a preferred embodiment of the present invention, the molar ratio of pentaerythritol to allyl halide is 1:3.5 to 4.2.

In a preferred embodiment of the present invention, the reaction temperature in step S2 is 60 to 120 ℃, the reaction time is 2 to 8 hours, and the heat-preserving time is 2 to 6 hours.

In a preferred embodiment of the present invention, the temperature for removing light components by atmospheric distillation in step S3 is 100 to 130 ℃; the temperature of the product collected by reduced pressure distillation is 130-160 ℃, and the vacuum degree is less than 20 mbar.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method of the invention takes PEP type polyether (R-Eon-POm-EOn-R) as a phase transfer catalyst. Both ends of the PEP type block copolyether are capped by alkyl, and the PEP type block copolyether can not participate in the reaction as a phase transfer catalyst, so that the generation of a byproduct can not be caused, the generation of a side reaction can be inhibited, the product yield is high, and the selectivity to pentaerythritol triallyl ether can reach more than 90%. In addition, the decomposition temperature of the phase transfer catalyst is far higher than the distillation temperature of the product, the decomposition and inactivation cannot occur in the reaction, and the phase transfer catalyst can be recycled, so that the phase transfer catalyst is an ideal phase transfer catalyst for preparing pentaerythritol allyl ether. Meanwhile, the PEP type polyether has low production cost and low toxicity, and the production cost of the product is reduced. The etherification reaction of the invention can be completed only under normal temperature and pressure, the operation process is simple, and the industrial production is easy. In conclusion, the invention effectively solves the problems that the phase transfer catalyst in the prior art is easy to participate in the reaction, has high cost, is difficult to recover and the like, has mild reaction conditions and low production cost, and accords with the green chemical concept.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

A preparation method of pentaerythritol allyl ether comprises the following steps:

s1, adding pentaerythritol, an alcohol salinization reagent and a phase transfer catalyst into a reaction kettle, stirring under normal pressure, and heating to 60-120 ℃; wherein, the phase transfer catalyst is PEP type polyether, and the structural formula is as follows: R-EOn-POm-EOn-R; wherein R is methyl (-CH)₃) Ethyl (-CH)₂CH₃) Or butyl (- (CH) - (CH))₂)₃CH₃) And n is 1: 1.5-3, and the molecular weight is 500-2000; the alcoholization reagent is an alkali metal hydroxide aqueous solution with the mass fraction of 35-55%; among them, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide, and sodium hydroxide is preferable. The molar ratio of the pentaerythritol to the alkali metal hydroxide is 1: 3.2-3.8; the mass ratio of the pentaerythritol to the phase transfer catalyst is 1: 0.02-0.2.

S2, adding an end capping agent allyl halide according to the molar ratio of pentaerythritol to allyl halide of 1: 3.5-4.2, controlling the reaction temperature to be 60-120 ℃ in the dropwise adding process and the reaction time to be 2-8 h, and preserving heat for 2-6 h after the reaction is finished to obtain a pentaerythritol allyl ether crude product; wherein the allyl halide is methyl chloropropene or methyl bromopropylene.

S3, washing the pentaerythritol allyl ether crude product obtained in the step S2 with water to dissolve salt generated in the reaction, unreacted alkali metal hydroxide and a phase transfer catalyst, separating a water layer and an organic layer, repeating twice, distilling the organic layer at 100-130 ℃ under normal pressure to remove light boiling substances, and distilling under reduced pressure at 130-160 ℃ under the vacuum degree of less than 20mbar to obtain the pentaerythritol allyl ether.

The PEP type end-capped polyether (R-Eon-POm-EOn-R) used in the invention is a block copolymer of Ethylene Oxide (EO) and Propylene Oxide (PO). In the present invention, a PEP type polyether is formed by continuously adding PO monomer to both ends of PEG (polyethylene glycol), and then capped with methyl or ethyl. By adjusting the molecular mass of PEG, the number of PO monomers and the difference of the capped alkyl, a series of PEP type capped polyethers with different alkyl end caps, different EO and PO block lengths and contents, are obtained.

The HLB value is defined as a ratio of the mass of EO groups to the total mass of EO and PO groups, i.e., HLB (mass of EO groups)/(mass of EO groups + mass of PO groups) × 100/5.

In the following examples of the present invention,

PEP730 is a PEP type terminated polyether with methyl terminated n-4 and m-6, and the molecular weight is 730;

PEP1078 is a PEP-type capped polyether with n-4 and m-12, which is methyl capped, and has a molecular weight of 1078;

the PEP758 is ethyl terminated PEP type terminated polyether with n being 4 and m being 6, and the molecular weight is 758;

PEP814 is a butyl terminated PEP-type capped polyether with n-4 and m-12, and has a molecular weight of 814.