A kind of preparation method of pentabromobenzyl acrylate

Abstract

The present invention belongs to the technical field of flame retardant materials, and specifically relates to a method for preparing pentabromobenzyl acrylate. The present invention provides a method for preparing pentabromobenzyl acrylate, comprising the following steps: mixing pentabromobenzyl alcohol, acrylate and a catalyst for ester exchange reaction to obtain a reaction liquid containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid; and the reaction liquid is separated into solid and liquid to obtain the pentabromobenzyl acrylate. The present invention uses a heteropoly acid to catalyze the ester exchange reaction between pentabromobenzyl alcohol and acrylate, and has high catalytic efficiency. The heteropoly acid catalyst also acts as an inhibitor, which effectively avoids the polymerization of acrylate in the reaction process, and prepares pentabromobenzyl acrylate. After the reaction is completed, the catalyst is removed by solid-liquid separation, or the excess acrylate is removed by reduced pressure distillation after the catalyst is removed, so that the pentabromobenzyl acrylate product can be obtained. The post-processing is simple, the product purity is high, the yield is high, and it is environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardant materials, and particularly relates to a preparation method of pentabromobenzyl acrylate. Background Art

[0002] Pentabromobenzyl acrylate is a new type of environmentally friendly flame retardant, which is characterized by high thermal stability, good processability, no migration and no blooming in the substrate. It is a necessary substance in the fields of military industry, textile, electronics, electrical, construction, etc. It has a wide range of applications in thermoplastic engineering plastics, especially suitable for manufacturing engineering plastics for complex electronic equipment.

[0003] The currently reported preparation method of pentabromobenzyl acrylate is mainly prepared by reacting acrylic acid and pentabromobenzyl bromide (chloride) in the presence of a phase transfer catalyst. However, this method requires the use of an irritating benzyl bromide (chloride) reagent, and an equivalent amount of salt is generated after the reaction, which needs to be further separated. The post-processing is complicated and the purity of the obtained product is low. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for preparing pentabromobenzyl acrylate. The preparation method provided by the present invention has simple post-processing and the prepared pentabromobenzyl acrylate has high purity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing pentabromobenzyl acrylate, comprising the following steps:

[0007] Pentabromobenzyl alcohol, acrylate and a catalyst are mixed to carry out an ester exchange reaction to obtain a reaction solution containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid;

[0008] The reaction liquid is separated into solid and liquid to obtain the pentabromobenzyl acrylate.

[0009] Preferably, the acrylic acid ester includes one or more of methyl acrylate, ethyl acrylate, isopropyl acrylate and n-propyl acrylate.

[0010] Preferably, the molar ratio of pentabromobenzyl alcohol to acrylate is 1:1-8.

[0011] Preferably, the molar ratio of pentabromobenzyl alcohol to acrylate is 1:4-6.

[0012] Preferably, when the molar ratio of pentabromobenzyl alcohol to acrylate is less than 1, the solid-liquid separation further comprises distilling the obtained liquid phase under reduced pressure.

[0013] Preferably, the conditions for the reduced pressure distillation include: a temperature of 70 to 125° C. and a pressure of 500 mmHg.

[0014] Preferably, the heteropoly acid includes one or more of phosphotungstic acid, silicotungstic acid, vanadotungstic acid and phosphomolybdic acid.

[0015] Preferably, the weight ratio of the heteropoly acid to pentabromobenzyl alcohol is 0.001 to 0.2:1.

[0016] Preferably, the temperature of the transesterification reaction is 75 to 150° C., and the time is 0.5 to 15 hours.

[0017] Preferably, the temperature of the transesterification reaction is 80-100° C. and the time is 2-3 hours.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The invention provides a method for preparing pentabromobenzyl acrylate, comprising the following steps: mixing pentabromobenzyl alcohol, acrylate and a catalyst for ester exchange reaction to obtain a reaction liquid containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid; and the reaction liquid is solid-liquid separated to obtain the pentabromobenzyl acrylate. In the invention, the pentabromobenzyl alcohol and acrylate are catalyzed by heteropoly acid for ester exchange reaction, and the catalytic efficiency is high. The heteropoly acid catalyst also acts as an inhibitor, which effectively avoids the polymerization of acrylate in the reaction process, and pentabromobenzyl acrylate is prepared. After the reaction is completed, the catalyst is removed by solid-liquid separation, or the excess acrylate is removed by reduced pressure distillation after the catalyst is removed, so that the pentabromobenzyl acrylate product can be obtained. The post-processing is simple, the product purity is high, the yield is high, and it is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is the H NMR spectrum of pentabromobenzyl acrylate prepared in Example 1;

[0022] Figure 2 This is the infrared spectrum of pentabromobenzyl acrylate prepared in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing pentabromobenzyl acrylate, comprising the following steps:

[0024] Pentabromobenzyl alcohol, acrylate and a catalyst are mixed to carry out an ester exchange reaction to obtain a reaction solution containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid;

[0025] The reaction liquid is separated into solid and liquid to obtain the pentabromobenzyl acrylate.

[0026] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0027] The invention mixes pentabromobenzyl alcohol, acrylate and a catalyst to carry out an ester exchange reaction to obtain a reaction liquid containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid.

[0028] In the present invention, the acrylic acid ester includes one or more of methyl acrylate, ethyl acrylate, isopropyl acrylate and n-propyl acrylate. The acrylic acid ester is a raw material for the transesterification reaction, and the excess acrylic acid ester can also be used as a solvent for the reaction.

[0029] In the present invention, the molar ratio of pentabromobenzyl alcohol to acrylate is preferably 1:1-8, more preferably 1:4-6. The molar ratio of pentabromobenzyl alcohol to acrylate in the present invention can make the fluidity of the reaction system good and facilitate the recycling of acrylate.

[0030] In the present invention, the heteropoly acid preferably includes one or more of phosphotungstic acid, silicotungstic acid, vanadotungstic acid and phosphomolybdic acid; more preferably, it is a mixture of phosphotungstic acid, silicotungstic acid and vanadotungstic acid, a mixture of phosphotungstic acid, silicotungstic acid and vanadotungstic acid or a mixture of phosphotungstic acid, phosphotungstic acid and vanadotungstic acid, the weight ratio of phosphotungstic acid, silicotungstic acid and vanadotungstic acid in the mixture of phosphotungstic acid, silicotungstic acid and vanadotungstic acid is preferably 1:1:1; the weight ratio of phosphotungstic acid, silicotungstic acid and vanadotungstic acid in the mixture of phosphotungstic acid, phosphotungstic acid and vanadotungstic acid is preferably 1:1:1; the weight ratio of phosphotungstic acid, phosphotungstic acid and vanadotungstic acid in the mixture of phosphotungstic acid, phosphotungstic acid and vanadotungstic acid is preferably 1:1:1. The heteropoly acid catalyst of the present invention can effectively prevent the polymerization of acrylate and can also act as a polymerization inhibitor.

[0031] In the present invention, the weight ratio of the heteropoly acid to pentabromobenzyl alcohol is preferably 0.001 to 0.2:1, more preferably 0.01 to 0.1:1, and even more preferably 0.015:1.

[0032] In the present invention, the transesterification reaction is preferably carried out in a reaction vessel equipped with a thermometer, a water separator and a stirrer.

[0033] In the present invention, the temperature of the transesterification reaction is preferably 75 to 150° C., more preferably 80 to 145° C., and more preferably 95 to 100° C.; the time is preferably 0.5 to 15 hours, more preferably 2 to 7.5 hours, and more preferably 5 to 5.5 hours. The reaction equation of the transesterification reaction is shown in Formula I, where pentabromobenzyl alcohol and acrylate undergo an esterification reaction under the action of a heteropolyacid catalyst to generate pentabromobenzyl acrylate.

[0034]

[0035] Wherein R is methyl, ethyl, n-propyl or isopropyl.

[0036] After obtaining the reaction liquid containing pentabromobenzyl acrylate, the present invention performs solid-liquid separation on the reaction liquid to obtain the pentabromobenzyl acrylate.

[0037] In the present invention, the solid-liquid separation method is preferably filtration, the solid obtained is a catalyst and can be recycled; the liquid obtained contains pentabromobenzyl acrylate. The solid-liquid separation is used to remove the catalyst in the reaction liquid.

[0038] In the present invention, when the molar ratio of pentabromobenzyl alcohol to acrylate is less than 1, that is, when the acrylate is in excess, the solid-liquid separation preferably further comprises distilling the obtained liquid phase under reduced pressure, and the function of the distillation under reduced pressure is to remove the excess acrylate. The conditions of the distillation under reduced pressure include: the temperature is preferably 70 to 125°C, more preferably 75 to 115°C, and the pressure is preferably 500 mmHg.

[0039] The preparation method of pentabromobenzyl acrylate provided by the present invention uses a heteropoly acid to catalyze pentabromobenzyl alcohol and acrylate to carry out an ester exchange reaction, the catalytic efficiency is high, the heteropoly acid catalyst also serves as a polymerization inhibitor, effectively avoiding the polymerization of acrylate in the reaction process, and preparing pentabromobenzyl acrylate. After the reaction is completed, the catalyst is removed, or after the catalyst is removed and the excess substrate acrylate is evaporated, the product can be directly obtained, the post-processing is simple, and the obtained pentabromobenzyl acrylate product has high purity, high yield, and is environmentally friendly.

[0040] In order to further illustrate the present invention, the preparation method of pentabromobenzyl acrylate provided by the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0041] Example 1

[0042] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 300 g of ethyl acrylate, and a catalyst (2.5 g each of phosphotungstic acid, silicotungstic acid, and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 95°C for 5.5 hours. The catalyst was filtered and recovered, and the excess ethyl acrylate was recovered by reduced pressure distillation at 75°C / 500 mm Hg to obtain 554.5 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.65% and a yield of 99.6%.

[0043] The product pentabromobenzyl acrylate was subjected to NMR and IR analysis, and the experimental data are as follows:

[0044] H NMR: (500 MHz, CDCl3) δ 6.45 (d, J = 15.0 Hz, 1H), 6.14 (dd, J = 15.0, 10.0 Hz, 1H), 5.89 (d, J = 10.0 Hz, 1H), 5.69 (s, 2H).

[0045] Infrared spectrum: (wave number, cm -1 )1735,1716,1406,1302,1180,980,802,550.

[0046] Figure 1 is the H NMR spectrum of pentabromobenzyl acrylate obtained in Example 1, Figure 2 This is the infrared spectrum of pentabromobenzyl acrylate prepared in Example 1.

[0047] Example 2

[0048] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 300 g of isopropyl acrylate, and a catalyst (3.5 g each of phosphomolybdic acid, silicotungstic acid, and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 145°C for 5 hours. The catalyst was filtered and recovered, and the excess isopropyl acrylate was recovered by reduced pressure distillation at 115°C / 500 mmHg to obtain 554.0 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.55% and a yield of 99.5%.

[0049] Example 3

[0050] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 688 g of methyl acrylate and a catalyst (100.5 g of vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 75°C for 2.5 hours. The catalyst was filtered and recovered, and the excess methyl acrylate was recovered by reduced pressure distillation at 75°C / 500 mmHg to obtain 540.2 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.57% and a yield of 97.0%.

[0051] Example 4

[0052] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 500 g of ethyl acrylate, and a catalyst (1.5 g each of phosphotungstic acid and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 100°C for 5 hours. The catalyst was filtered and recovered, and the excess ethyl acrylate was recovered by reduced pressure distillation at 85°C / 500 mmHg to obtain 550.5 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.62% and a yield of 98.9%.

[0053] Example 5

[0054] In a reaction vessel, add weighed pentabromobenzyl alcohol 502.6 g, methyl acrylate 86 g, and catalyst (0.25 g each of silicotungstic acid and vanadotungstic acid), install a condenser, a water separator, and a magnetic stirrer for stirring, heat in an oil bath, control the temperature at 150°C to react for 0.5 hour, filter while hot, and obtain the product pentabromobenzyl acrylate 545.6 g, with a liquid phase purity of 99.52% and a yield of 98.0%.

[0055] Example 6

[0056] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 500 g of ethyl acrylate, and a catalyst (6.25 g each of silicotungstic acid and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 115°C for 4 hours. The catalyst was filtered and recovered, and the excess ethyl acrylate was recovered by reduced pressure distillation at 85°C / 500 mmHg to obtain 550.2 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.61% and a yield of 98.8%.

[0057] Example 7

[0058] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 360 g of isopropyl acrylate, and a catalyst (2.0 g each of silicotungstic acid and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 130°C for 12 hours. The catalyst was filtered and recovered, and the excess isopropyl acrylate was recovered by reduced pressure distillation at 115°C / 500 mmHg to obtain 548.8 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.64% and a yield of 98.6%.

[0059] Example 8.

[0060] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 150 g of ethyl acrylate, and a catalyst (12 g each of phosphotungstic acid, phosphomolybdic acid, and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 130°C for 7.5 hours. The catalyst was filtered and recovered, and the excess ethyl acrylate was recovered by reduced pressure distillation at 85°C / 500 mmHg to obtain 553.0 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.69% and a yield of 99.3%.

[0061] Example 9

[0062] In a reaction vessel, 502.6 g of pentabromobenzyl alcohol, 400 g of n-propyl acrylate, and a catalyst (3.0 g each of silicotungstic acid and vanadotungstic acid) were added, a condenser and a water separator were installed, the mixture was stirred with an agitator, heated in an oil bath, and the temperature was controlled to react at 135°C for 10 hours. The catalyst was filtered and recovered, and the excess n-propyl acrylate was recovered by reduced pressure distillation at 120°C / 500 mmHg to obtain 545.6 g of pentabromobenzyl acrylate as a product, with a liquid phase purity of 99.55% and a yield of 98.0%.

[0063] Comparative Example 1

[0064] In a reaction vessel, add weighed pentabromobenzyl alcohol 502.6 g, ethyl acrylate 500 g, molybdenum vanadium phosphate (CAS No.: 56188-77-3) 12.5 g, install a condenser and a water separator, stir with a stirrer, heat in an oil bath, control the temperature at 110 ° C to react for 6 hours, filter and recover the catalyst, filter at 85 ° C / 500 mmHg, and remove excess ethyl acrylate by reduced pressure distillation to obtain 520.3 g of product pentabromobenzyl acrylate with a liquid phase purity of 93.87% and a yield of 93.4%.

[0065] Comparative Example 2

[0066] In a reaction vessel, add weighed pentabromobenzyl alcohol 502.6 g, ethyl acrylate 500 g, and molybdenum vanadium phosphate 3.0 g, install a condenser and a water separator, stir with an agitator, heat in an oil bath, control the temperature at 100 ° C to react for 5 hours, filter and recover the catalyst, and recover the excess ethyl acrylate by reduced pressure distillation at 85 ° C / 500 mmHg to obtain 508.9 g of product pentabromobenzyl acrylate with a liquid phase purity of 91.66% and a yield of 91.4%.

[0067] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing pentabromobenzyl acrylate, characterized in that: For the following steps: Pentabromobenzyl alcohol, acrylic acid ester and a catalyst are mixed for ester exchange reaction to obtain a reaction solution containing pentabromobenzyl acrylate; the catalyst is a heteropoly acid; the heteropoly acid includes one or more of phosphotungstic acid, silicotungstic acid, vanadotungstic acid and phosphomolybdic acid; the molar ratio of pentabromobenzyl alcohol to acrylic acid ester is 1:1-8; The reaction liquid is separated into solid and liquid to obtain the pentabromobenzyl acrylate; when the molar ratio of the pentabromobenzyl alcohol to the acrylate is less than 1, the solid-liquid separation further comprises distilling the obtained liquid phase under reduced pressure.

2. The preparation method according to claim 1, characterized in that: The acrylic acid ester includes one or more of methyl acrylate, ethyl acrylate, isopropyl acrylate and n-propyl acrylate.

3. The preparation method according to claim 1, characterized in that: The molar ratio of pentabromobenzyl alcohol to acrylate is 1:4-6.

4. The preparation method according to claim 1, characterized in that: The conditions of the reduced pressure distillation include: a temperature of 70 to 125° C. and a pressure of 500 mmHg.

5. The preparation method according to claim 1, characterized in that: The weight ratio of the heteropoly acid to pentabromobenzyl alcohol is 0.001 to 0.2:

1.

6. The preparation method according to claim 1, characterized in that: The temperature of the transesterification reaction is 75 to 150° C., and the time is 0.5 to 15 hours.

7. The preparation method according to claim 6, characterized in that: The temperature of the transesterification reaction is 80-100° C. and the time is 2-3 hours.

Images