A kind of preparation method of pentaerythritol triallyl ether

Abstract

The invention discloses a preparation method of pentaerythritol triallyl ether, wherein the method comprises: providing reaction raw materials and a catalyst, heating to a preset temperature and keeping the temperature for a first preset time, controlling water separation in a first mode and dripping propylene chloride at a first preset speed for 5 hours to obtain a first-stage reaction product; adding alkali solution and a catalyst into the product of the previous reaction step three times and controlling water separation in a second water separation mode, a third water separation mode, and a fourth water separation mode, wherein the water separation in the first mode includes no water separation during all reaction time, the water separation in the second mode includes water separation during part of the reaction time, the water separation in the third mode includes water separation during all reaction time, and the water separation in the fourth mode includes water separation during all reaction time. By controlling different water separation modes, the selectivity of the triether can be effectively improved, the cost of pentaerythritol triallyl ether can be effectively reduced, and its application field is conducive to further expansion.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method for preparing pentaerythritol triallyl ether. Background Art

[0002] Pentaerythritol triallyl ether is an important chemical product, widely used in the organic synthesis of polyol ethers, as a raw material or intermediate for resin synthesis. With the increasing economic development and industrial competition, how to produce high-quality pentaerythritol triallyl ether with good quality and low price has become a problem to be solved in the industry.

[0003] We know that pentaerythritol triallyl ether is usually a mixture of pentaerythritol monoallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether and pentaerythritol tetraallyl ether. Existing processes are different, but the selectivity of pentaerythritol triallyl ether (triether) is usually lower than 75%, and to improve its selectivity, either expensive raw materials are selected, or the purification cost of the reaction product and the processing cost of the reaction by-products are increased, which hinders the further expansion of the application field of pentaerythritol triallyl ether. Summary of the invention

[0004] In order to solve the above technical problems, the present application discloses a method for preparing pentaerythritol triallyl ether, which can solve the problems of low selectivity of the target product and high preparation cost, and is conducive to further expansion of the application field of pentaerythritol triallyl ether.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing pentaerythritol triallyl ether, wherein the method comprises: step S100: putting pentaerythritol, alkali solution, tetrabutylammonium bromide and dimethyl sulfoxide into a reaction kettle, heating to a preset temperature and keeping the temperature for a first preset time, controlling water separation in a first mode and dripping allyl chloride at a first preset speed for 5 hours to obtain a first-stage reaction product; step S200: adding alkali solution and a catalyst to the first-stage reaction product, controlling water separation in a second mode and dripping allyl chloride at a second preset speed for 10 hours to obtain a second-stage product; step S300: adding the second-stage product to the reaction kettle; Adding alkali solution and catalyst, controlling water separation in the third mode and dripping allyl chloride at a third preset speed for no more than 11 hours to obtain a third-stage product; step S400: adding alkali solution and catalyst to the third-stage product, controlling water separation in the fourth mode and dripping allyl chloride at a fourth preset speed for no more than 2 hours to obtain a reaction product; wherein, the water separation in the first mode includes not dividing water during all reaction time, the water separation in the second mode includes dividing water during part of the reaction time, the water separation in the third mode includes dividing water during all reaction time, and the water separation in the fourth mode includes dividing water during all reaction time.

[0007] Wherein, in the step S100, the mass ratio of pentaerythritol, alkali solution, tetrabutylammonium bromide, dimethyl sulfoxide and allyl chloride is 2500:(5000-5500):(100-120):(200-250):(4400-4900).

[0008] Wherein, the preset temperature is 90-110° C., and the preset time is 20-40 minutes.

[0009] Wherein, in the step S200, the water separation during part of the reaction time is specifically: when the dripping amount of the allyl chloride reaches 50%-70% of the total dripping mass, the water separation operation is started.

[0010] Wherein, in the step S200, the mass ratio of liquid alkali: tetrabutylammonium bromide: allyl chloride is (5000-5500):(100-120):(4400-4900).

[0011] Wherein, in the step S300, the mass ratio of liquid alkali:tetrabutylammonium bromide:propylene chloride is (1000-1300):(30-50):(1800-2100).

[0012] Wherein, in the step S400, the mass ratio of liquid alkali:tetrabutylammonium bromide:propylene chloride is (700-800):(15-20):(1200-1400).

[0013] The method further comprises: step S500, checking the quality of the reaction product obtained in step S400, and if the quality does not meet the preset requirement, adding alkali solution and allyl chloride of equal quality to react.

[0014] Wherein, the preset requirement includes that the molar fraction of pentaerythritol triallyl ether in the reaction product is greater than 75%.

[0015] Wherein, the method further includes: the first dripping acceleration < the fourth dripping acceleration < the third dripping acceleration < the second dripping acceleration.

[0016] Different from the prior art, the preparation method of the present application can effectively improve the conversion rate of pentaerythritol triallyl ether and the selectivity of triether under the condition of the same feed cost by dividing the reaction process into multiple steps and controlling the water separation method in each step, thereby effectively reducing the cost of pentaerythritol triallyl ether, which is conducive to further expansion of the application field of pentaerythritol triallyl ether. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a gas chromatographic characterization chart of Example 1 in the preparation method of pentaerythritol triallyl ether of the present application. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the accompanying drawings.

[0019] A method for preparing pentaerythritol triallyl ether, wherein the method comprises: step S100: putting pentaerythritol, alkali solution, tetrabutylammonium bromide and dimethyl sulfoxide into a reaction kettle, heating to a preset temperature and keeping the temperature for a first preset time, controlling water separation in a first mode and dripping allyl chloride at a first preset speed for 5 hours to obtain a first-stage reaction product; step S200: adding alkali solution and a catalyst to the first-stage reaction product, controlling water separation in a second mode and dripping allyl chloride at a second preset speed for 10 hours to obtain a second-stage product; step S300: adding the second-stage product to the reaction kettle; Adding alkali solution and catalyst, controlling water separation in the third mode and dripping allyl chloride at a third preset speed for no more than 11 hours to obtain a third-stage product; step S400: adding alkali solution and catalyst to the third-stage product, controlling water separation in the fourth mode and dripping allyl chloride at a fourth preset speed for no more than 2 hours to obtain a reaction product; wherein, the water separation in the first mode includes not dividing water during all reaction time, the water separation in the second mode includes dividing water during part of the reaction time, the water separation in the third mode includes dividing water during all reaction time, and the water separation in the fourth mode includes dividing water during all reaction time.

[0020] In this embodiment, by dividing the reaction process into multiple steps and controlling the water separation method in each step, the conversion rate of pentaerythritol triallyl ether and the selectivity of triether can be effectively improved under the same feed cost, and the cost of pentaerythritol triallyl ether can be effectively reduced, which is conducive to further expansion of the application field of pentaerythritol triallyl ether.

[0021] Further, the preset temperature is 90-110°C, such as 90. The preset time is 20-40 minutes, such as 20 minutes, 30 minutes or 40 minutes, etc. If it is conducive to obtaining better product selectivity, the preset temperature and preset time of each stage can be adjusted, combined and set according to the actual operation conditions. Further, the reaction temperatures in steps S100, S200, S300, S400 and S500 are controlled to be the same or different, and the reaction temperature range is 95-100°C. In one embodiment, for the convenience of control, the temperature of each stage of the reaction is the same, such as 95°C; of course, in order to obtain a better product conversion rate, etc., the reaction temperature of each reaction stage can be controlled differently according to the actual situation, which will not be repeated here.

[0022] In this embodiment, tetrabutylammonium bromide in step S100 is used as a catalyst. Of course, the catalyst can also be selected from polyether, quaternary ammonium salt, and tertiary amine; similarly, since the reaction principle of subsequent steps S200, S300, S400, and S500 is the same as that of step S100, but the control of the reaction conditions is different, the catalyst in the subsequent reaction steps can be the same or different from the catalyst selected in step S100. In one embodiment, in order to simplify the operation, the catalyst type of each step is the same, and further, the catalyst is tetrabutylammonium bromide.

[0023] Further, the alkali solution can be a common alkali solution such as a sodium hydroxide solution and a potassium hydroxide solution, which is used to provide an alkaline environment for the reaction. The solute and concentration of the alkali solution can be determined according to the actual situation. For example, the alkali solution is a caustic soda solution with a mass fraction of 50%, a caustic soda solution with a mass fraction of 60%, or a caustic soda solution with a mass fraction of 70%. In the actual operation process, the alkali solution with the above concentration range can be obtained by mixing a 99% caustic soda solution with water. In some embodiments, the alkali solution is a caustic soda solution with a mass fraction of 50%.

[0024] In some embodiments, the water separation during part of the reaction time in step S200 is specifically as follows: when the amount of the allyl chloride added reaches 50%-70% of the total added mass, the water separation operation is started. Specifically, the water separation operation is started when the amount of the allyl chloride added reaches 50%, 60% or 70% of the total added mass.

[0025] In some embodiments, the method further comprises: in step S500, checking the quality of the reaction product obtained in step S400, and if it does not meet the preset requirements, continuing to add alkali solution and propylene chloride of equal mass to react. Specifically, the preset requirements include that the molar fraction of pentaerythritol triallyl ether in the reaction product is greater than 75%. That is, in this embodiment, in order to ensure that the selectivity of pentaerythritol triallyl ether in the product meets the requirements, the reactant feed can be appropriately increased.

[0026] In some embodiments, the method further comprises: the first dropping speed < the fourth dropping speed < the third dropping speed < the second dropping speed. According to the characteristics of the reaction system in each reaction stage, by adjusting the dropping speed of allyl chloride in each stage, the conversion rate and selectivity of the product can be improved, thereby reducing production costs and improving product competitiveness.

[0027] In one embodiment, pentaerythritol is added at one time, and the remaining raw materials are added in stages. The control of the input amount and reaction conditions in each stage can effectively improve the conversion rate and selectivity of the product. Specifically, the mass ratio of pentaerythritol, alkali solution, tetrabutylammonium bromide, dimethyl sulfoxide and allyl chloride in step S100 is 2500:(5000-5500):(100-120):(200-250):(4400-4900), such as the mass ratio of pentaerythritol, caustic soda solution with a mass fraction of 50%, tetrabutylammonium bromide, dimethyl sulfoxide and allyl chloride in step S100 is 2500:5250:110:225:4649. In the step S200, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (5000-5500): (100-120): (4400-4900), such as, in the step S200, the mass ratio of caustic soda solution with a mass fraction of 50%, tetrabutylammonium bromide, dimethyl sulfoxide and allyl chloride is 5250: 110: 4649. In the step S300, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (1000-1300): (30-50): (1800-2100), such as, in the step S300, the mass ratio of caustic soda solution with a mass fraction of 50%: tetrabutylammonium bromide: allyl chloride is 1165: 37: 1950. In step S400, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (700-800): (15-20): (1200-1400), for example, the mass ratio of caustic soda solution with a mass fraction of 50%: tetrabutylammonium bromide: allyl chloride is 748: 18: 1271. In summary, in the process of splitting the entire reaction process into multiple steps for fine control, due to the different water content in each stage, by gradually increasing the proportion of allyl chloride in different reaction stages, the conversion rate and selectivity can be improved to a certain extent.

[0028] The technical solution of the present application is explained below through embodiments:

[0029] Comparative Example 1:

[0030] 250 kg of pentaerythritol was put into the provided reactor, and then 4284 kg of caustic soda solution with a mass fraction of 50%, 103 kg of tetrabutylammonium bromide catalyst, and 23 kg of dimethyl sulfoxide were put into the reactor, and the temperature was raised to 100 ° C and kept warm for 30 minutes. The temperature of the reaction system was controlled at 95-100 ° C, and 4861 kg of propylene chloride was added dropwise within 28 hours under the condition of continuous water separation. The molar fraction of pentaerythritol triallyl ether in the reaction product was detected to be 73% (less than 75%).

[0031] Embodiment 1:

[0032] 1) First stage: first, 250 kg of pentaerythritol was added to the provided reactor, then 525 kg of 50% caustic soda solution, 11 kg of tetrabutylammonium bromide catalyst, and 23 kg of dimethyl sulfoxide were added to the reactor, and the temperature was raised to 100°C and kept warm for 30 minutes. The temperature of the reaction system was controlled at 95-100°C, and 465 kg of propylene chloride was added dropwise within 7 hours without water separation.

[0033] 2) The second stage: 2403 kg of 50% caustic soda solution and 50 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 95-100° C., 857 kg of allyl chloride was added dropwise, and water separation began, until 1271 kg of allyl chloride was added dropwise. The total time for adding the above allyl chloride dropwise was 7 hours.

[0034] 3) The third stage: 1169 kg of 50% caustic soda solution and 37 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 90-100° C., and 1950 kg of allyl chloride was added dropwise within 7 hours under continuous water separation.

[0035] 4) The fourth stage: 187 kg of 50% caustic soda solution and 5 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 90-100° C., and 318 kg of allyl chloride was added dropwise within 7 hours under continuous water separation. The molar fraction of pentaerythritol triallyl ether in the reaction product was detected to be 80% (greater than 75%).

[0036] Table 1 Comparison of reaction conditions in Example 1

[0037] Stage / Dosage(kg) 50% caustic soda solution Tetrabutylammonium bromide Allyl chloride Dropping speed (kg / h) Phase 1 525 11 465 66.5 Phase II 2403 50 2128 304 Phase 3 1169 37 1950 278.6 Stage 4 187 5 318 45.5

[0038] In summary, by comparing Comparative Example 1 and Example 1, it can be seen that adopting a staged reaction and controlling the water separation method can effectively improve the conversion rate of pentaerythritol triallyl ether and the selectivity of the triether, effectively reduce the cost of pentaerythritol triallyl ether, and is conducive to further expansion of the application field of pentaerythritol triallyl ether.

[0039] Embodiment 2:

[0040] 1) First stage: firstly, 250 kg of pentaerythritol was put into the provided reactor, then 525 kg of 50% caustic soda solution, 11 kg of tetrabutylammonium bromide catalyst, and 23 kg of dimethyl sulfoxide were put into the reactor, and the temperature was raised to 100°C and kept warm for 30 minutes. The temperature of the reaction system was controlled at 95-100°C, and 465 kg of propylene chloride was added dropwise within 5 hours without water separation.

[0041] 2) The second stage: 2403 kg of 50% caustic soda solution and 50 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 95-100° C., 857 kg of allyl chloride was added dropwise, and water separation began until another 1271 kg of allyl chloride was added dropwise. The total time for adding the above allyl chloride dropwise was 10 hours.

[0042] 3) The third stage: 1169 kg of 50% caustic soda solution and 37 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 90-100° C., and 1950 kg of allyl chloride was added dropwise within 11 hours while continuously removing water.

[0043] 4) The fourth stage: 187 kg of 50% caustic soda solution and 5 kg of tetrabutylammonium bromide catalyst were added to the reactor, the temperature of the reaction system was controlled at 90-100°C, and 318 kg of propylene chloride was added dropwise within 2 hours under the condition of continuous water separation. The molar fraction of pentaerythritol triallyl ether in the reaction product was detected to be 82% (greater than 75%). The characterization results are detailed in the attached Figure 1 .

[0044] Table 2 Comparison of reaction conditions in Example 2

[0045] Stage / Dosage(kg) 50% caustic soda solution Tetrabutylammonium bromide Allyl chloride Dropping speed (kg / h) Phase 1 525 11 465 93 Phase II 2403 50 2128 212.8 Phase 3 1169 37 1950 177.2 Stage 4 187 5 318 159

[0046] In summary, by comparing Comparative Example 1 and Example 2, it can be seen that the staged reaction can effectively improve the conversion rate of pentaerythritol triallyl ether and the selectivity of triether by controlling the dripping speed and the water separation method. Further, by comparing Example 1 and Example 2, it can be seen that on the basis of staged reaction and controlling the water separation method, the dripping method can further improve the conversion rate of pentaerythritol triallyl ether and the selectivity of triether. It can be seen that the preparation method of the present application is superior.

[0047] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing pentaerythritol triallyl ether, characterized in that: The method comprises: Step S100: putting pentaerythritol, alkali solution, tetrabutylammonium bromide and dimethyl sulfoxide into a reaction kettle, heating to a preset temperature and keeping the temperature for a first preset time, controlling water separation in a first mode and dripping allyl chloride at a first preset speed for 5 hours to obtain a first stage reaction product; Step S200: adding alkali solution and catalyst to the first stage reaction product, controlling water separation in a second mode and dripping allyl chloride at a second preset speed for 10 hours to obtain a second stage product; Step S300: adding alkali solution and catalyst to the second stage product, controlling water separation in a third mode and dripping allyl chloride at a third preset speed for no more than 11 hours to obtain a third stage product; Step S400: adding alkali solution and catalyst to the product of the third stage, controlling water separation in a fourth mode and dripping allyl chloride at a fourth preset speed for no more than 2 hours to obtain a reaction product; The first mode of water splitting includes not splitting water during all reaction time, the second mode of water splitting includes splitting water during part of the reaction time, the third mode of water splitting includes splitting water during all reaction time, and the fourth mode of water splitting includes splitting water during all reaction time; the catalysts in step S200, step S300 and step S400 are all tetrabutylammonium bromide; The preset temperature is 90-110° C., and the first preset time is 20-40 minutes. In the step S100, the mass ratio of pentaerythritol, alkali solution, tetrabutylammonium bromide, dimethyl sulfoxide and allyl chloride is 2500:(5000-5500):(100-120):(200-250):(4400-4900. In the step S200, the water separation during the partial reaction time is specifically: when the amount of allyl chloride added reaches 50%-70% of the total added mass, the water separation operation is started. In the step S200, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (5000-5500):(100-120):(4400-4900); in the step S300, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (1000-1300):(30-50):(1800-2100); in the step S400, the mass ratio of liquid caustic soda: tetrabutylammonium bromide: allyl chloride is (700-800):(15-20):(1200-1400).

2. The preparation method according to claim 1, characterized in that: The method further comprises: Step S500, checking the quality of the reaction product obtained in step S400, if it does not meet the preset requirements, then continue to add the same mass of alkali solution and allyl chloride to react.

3. The preparation method according to claim 2, characterized in that: The preset requirement includes that the molar fraction of pentaerythritol triallyl ether in the reaction product is greater than 75%.

4. The preparation method according to claim 1, characterized in that: The method also includes: the first dripping acceleration<the fourth dripping acceleration<the third dripping acceleration<the second dripping acceleration.

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