Preparation method of tert-amyl peroxypivalate and initiator

Abstract

The invention discloses a preparation method of tert-amyl peroxypivalate and an initiator, and belongs to the technical field of preparation of initiators. The preparation method comprises the following steps: by taking water as a solvent, when tert-amyl hydrogen peroxide and caustic soda liquid react to generate tert-amyl peroxide salt, the tert-amyl peroxide salt and pivaloyl chloride are subjected to substitution reaction to obtain the tert-amyl peroxide, and the substitution reaction speed of the pivaloyl chloride is higher than the hydrolysis speed of the pivaloyl chloride. Auxiliary materials are dispersed in an oil phase, shearing and emulsifying are carried out, the peroxide pivalate initiator is obtained, the auxiliary materials comprise an emulsifying agent, a dispersing agent, an anti-freezing agent and water, and the oil phase adopts the peroxide pivalate obtained through the method. The oil-phase raw material residue is low, and the storage stability time of the initiator emulsion prepared from the oil phase is longer than 30 months.

Description

Technical Field

[0001] The invention belongs to the technical field of initiator preparation, and more specifically, relates to a method for preparing pivalic acid peroxide and an initiator. Background Art

[0002] Organic peroxide liquid initiators are mainly divided into two types: solvent-based and emulsion-based. They are used according to different polymerization types. Solvent-based initiators are generally used in bulk polymerization, without dispersion requirements, and have high polymerization efficiency. Emulsion-based initiators are often used in suspension polymerization. The particle size of the dispersed phase of the initiator in the emulsion-based product is small, and the initiation efficiency and the stability of the initiation polymerization process are good. Tri-pentyl peroxide (TAPV) is a colorless, transparent, oily liquid that can be used to prepare emulsion-based initiators. However, the synthesis process of peroxide initiators in the industry is a two-step dropwise production process. In the first step, the base and hydrogen / alkyl peroxide are mixed to react to generate peroxide salts. In the second step, the acyl chloride is added, and the peroxide salts and acyl chlorides react to generate peroxide initiators. The advantage of this method is that a large amount of peroxide salts are generated in the first step, and the forward reaction can be quickly carried out after the acyl chloride is added. The disadvantage is that the two-step dropwise reaction time is long, and the reaction process is highly exothermic, and there are many unfavorable factors such as acyl chloride hydrolysis side reactions.

[0003] For example, the patent application document with Chinese patent application number 202111395631.4 and application publication date January 28, 2022 discloses a low-water emulsion type tri-pentyl peroxy pivalate and its preparation method. The initiator of this patent includes the following components in mass percentage: oil phase: 40% to 60%, emulsifier: 0.5% to 2%, dispersant: 2% to 5%, antifreeze: 10% to 30%, and the balance is deionized water; its preparation process is divided into two steps: synthesis and configuration. The first step is to synthesize the oil phase to make the oil phase; the second step is to mix the oil phase obtained in the first step with the emulsifier, dispersant, and antifreeze deionized water, and then homogenize and emulsify to obtain a stable emulsion product. The oil phase is tri-amyl peroxy pivalate, and the preparation method is to first mix liquid alkali, deionized water and polyoxyethylene polyoxypropylene block copolymer, and stir; then drop tri-amyl hydroperoxide, and stir; finally, drop pivaloyl chloride, stir, and stand to separate water to complete the preparation of the oil phase. However, the preparation of the oil phase is carried out in two steps.

[0004] Therefore, in order to realize the one-step reaction preparation of tri-amyl peroxide pivalate, and the emulsion initiator prepared therefrom has high stability, it is urgent to develop a preparation method of tri-amyl peroxide pivalate and initiator. Summary of the invention

[0005] 1. Problem to be solved

[0006] In view of the problem that the existing preparation of tri-amyl peroxy pivalate needs to be completed in steps, the present invention provides a preparation method of tri-amyl peroxy pivalate, which optimizes the raw material formula and matches a new one-step preparation process to achieve a short synthesis process and a simple production process, and is easy to scale up industrially. A preparation method of a tri-amyl peroxy pivalate emulsion initiator is further provided, wherein the raw material residual value is less than 0.1%, and the initiator emulsion stability can reach more than 30 months.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] As a first aspect of the present application, the present application provides a method for preparing pivaloyl peroxide, which is a one-step method, comprising the following steps: using water as a solvent, while pivaloyl hydrogen peroxide reacts with liquid alkali to generate pivaloyl peroxide salt, the pivaloyl peroxide salt immediately undergoes a substitution reaction with pivaloyl chloride to obtain pivaloyl peroxide, wherein the speed of the substitution reaction of pivaloyl chloride is greater than the hydrolysis speed of pivaloyl chloride, and the two synthesis reactions are required to respond quickly, that is, the pivaloyl peroxide salt immediately reacts with the pivaloyl chloride after being generated.

[0010] Furthermore, the applicant provides a specific operation with rapid response of the above two synthetic reactions, that is, firstly, t-amyl hydroperoxide is mixed with water, and then liquid alkali and pivaloyl chloride are added dropwise at the same time, the dropping speed v1 of the liquid alkali is controlled to be greater than the dropping speed v2 of the pivaloyl chloride, and after the dropping is completed, the product (t-amyl peroxy pivalate oil phase) is packaged after stirring and removing water, wherein v2=(0.492-0.494)*v1.

[0011] Furthermore, the dripping speed v1 of the liquid caustic soda is 2.7 to 3.3 L / min, and the dripping speed v2 of the pivaloyl chloride is 1.33 to 1.63 L / min.

[0012] Furthermore, the matching relationship between the dropping speed v1 of the liquid caustic soda and the dropping speed v2 of the pivaloyl chloride is:

[0013] v1=2.7L / min, v2=1.33L / min; or,

[0014] v1=2.8L / min, v2=1.38L / min; or,

[0015] v1=2.9L / min, v2=1.43L / min; or,

[0016] v1=3.0L / min, v2=1.48L / min.

[0017] Furthermore, the concentration of the liquid alkali is 30%, and the concentration of the pivaloyl chloride is 99%.

[0018] Furthermore, the temperature of the reaction system is maintained below 30° C. during the mixing of tert-amyl hydroperoxide and water; and the temperature of the reaction system is maintained below 35° C. during the dropwise addition of liquid alkali and pivaloyl chloride.

[0019] Furthermore, the mass fractions of liquid alkali, p-amyl hydroperoxide, pivaloyl chloride and deionized water are as follows:

[0020]

[0021] Furthermore, the water is preferably deionized water.

[0022] As the second aspect of the present application, the present application provides a method for preparing a tri-pentyl pivalate peroxide initiator, the steps of which are: dispersing auxiliary materials in an oil phase, shearing and emulsifying, to obtain the tri-pentyl pivalate peroxide initiator, wherein the auxiliary materials include but are not limited to emulsifiers, dispersants, antifreeze agents and water, and the oil phase is the tri-pentyl pivalate peroxide obtained by the above-mentioned preparation method.

[0023] Furthermore, during the process of dispersing the auxiliary materials in the oil phase, the temperature of the system is controlled below 0° C. The auxiliary materials are added to the oil phase and stirred for 10 minutes to be evenly dispersed.

[0024] Furthermore, shear emulsification was performed in an emulsifying kettle, and after stirring for 10 minutes, emulsification was performed for 30 minutes to complete the preparation.

[0025] Furthermore, the emulsifier is stearic acid polyoxyethylene ether (SG-100); the dispersant is polyvinyl alcohol (PVA 4040); and the antifreeze agent is methanol.

[0026] Furthermore, the weight fractions of the oil phase and auxiliary materials are:

[0027]

[0028] Furthermore, the water is preferably deionized water.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention determines the best synthesis and preparation method through the demonstration of the best raw material ratio and production process. The oil phase yield of the tri-amyl peroxy pivalate prepared by the present invention can reach more than 95%, and the oil phase content can reach more than 99.5%; the raw material residual value in the finished initiator product is less than 0.1%, so the initiator emulsion stability of the present invention can reach more than 30 months, and the initiator "induced decomposition" effect caused by the residual tri-amyl hydroperoxide can be greatly reduced during the initiation of polymerization, thereby greatly improving the initiation efficiency and reducing the amount of initiator added and the polymerization reaction time.

[0032] (2) The present invention innovatively develops a one-step dropwise synthesis method in which liquid caustic soda and pivaloyl chloride are added dropwise together. During the dropwise addition, the liquid caustic soda first reacts with pivaloyl hydroperoxide to generate pivaloyl sodium peroxide, and then pivaloyl sodium peroxide reacts with pivaloyl chloride to generate pivaloyl peroxide pivaloyl ester (TAPV). In this process, the dropwise addition rate of the liquid caustic soda and pivaloyl chloride is a key process control point. The molar addition rate of the liquid caustic soda should be slightly higher than the molar addition rate of pivaloyl chloride, otherwise the generation rate of pivaloyl sodium peroxide will be too low, thereby causing a large amount of hydrolysis of the acyl chloride, affecting the product yield and purity. Moreover, only if the molar addition rate of the liquid caustic soda is higher than the molar addition rate of pivaloyl chloride, it is impossible to simultaneously achieve a low residual content of raw materials in the oil phase and a storage stability of the initiator emulsion of 30 months. Therefore, the applicant has found that the matching relationship between the dropwise addition rate v1 of the liquid caustic soda and the dropwise addition rate v2 of the pivaloyl chloride needs to meet the relationship formula v2=(0.492-0.494)*v1 in order to simultaneously achieve the above-mentioned expected effects.

[0033] (3) The preparation method of tri-amyl peroxy pivalate of the present invention is completed in one step, and the synthesis process can be finely controlled during production, which greatly avoids the occurrence of large amounts of heat release in the middle of the reaction and improves the safety of the production process. At the same time, the one-step synthesis method inhibits the occurrence of side reactions such as hydrolysis of acyl chloride, so that the content of the oil phase can reach more than 99.5%, and the residue is reduced to less than 0.1%.

[0034] (4) In the preparation method of tri-amyl peroxy pivalate of the present invention, a synthetic product formula suitable for the present process is developed in conjunction with the one-step dropping method. By adjusting the ratio of the three components of liquid alkali, tri-amyl hydroperoxide, and pivaloyl chloride, a product oil phase synthesis formula suitable for the present process is determined, and the adjustable space of the present formula is very small. Only within the formula range required by the present invention and the one-step dropping process requirements can the effect described in the present invention be achieved. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] The raw materials for synthesizing pivaloyl peroxide in this embodiment are: 15 g of pivaloyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0038] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0039] In this embodiment, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: SG-100 1%, PVA-4040 3%, methanol 20%, oil phase 52%, and deionized water 24%.

[0040] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0041] Example 2

[0042] The raw materials for synthesizing pivaloyl peroxide in this embodiment are: 15 g of pivaloyl hydroperoxide (purity 90%), 27 g of liquid caustic soda (purity 30%), 13 g of pivaloyl chloride (purity 99%), and 45 g of deionized water.

[0043] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0044] In this embodiment, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: SG-100 1%, PVA-4040 3%, methanol 20%, oil phase 52%, and deionized water 24%.

[0045] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0046] Example 3

[0047] The raw materials for synthesizing pivaloyl peroxide in this embodiment are: 15 g of pivaloyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0048] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 2.7 L / min, the pivaloyl chloride addition rate is 1.33 L / min, the temperature is controlled below 30°C, stirring is performed for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0049] In this embodiment, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: SG-100 1%, PVA-4040 3%, methanol 20%, oil phase 52%, and deionized water 24%.

[0050] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0051] Example 4

[0052] The raw materials for synthesizing pivaloyl peroxide in this embodiment are: 15 g of pivaloyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0053] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.3 L / min, the pivaloyl chloride addition rate is 1.63 L / min, the temperature is controlled below 30°C, stirring is performed for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0054] In this embodiment, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: SG-100 1%, PVA-4040 3%, methanol 20%, oil phase 52%, and deionized water 24%.

[0055] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0056] Comparative Example 1

[0057] The difference between Comparative Example 1 and the solution of the present invention is that the dropping rate of the acyl chloride is too slow.

[0058] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0059] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.43 L / min, the temperature is controlled below 30°C, stirring is performed for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0060] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0061] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0062] Comparative Example 2

[0063] The difference between Comparative Example 2 and the solution of the present invention is that the acyl chloride is added dropwise too quickly.

[0064] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0065] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.53 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0066] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0067] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0068] Comparative Example 3

[0069] The difference between Comparative Example 3 and the solution of the present invention is that the liquid alkali dripping acceleration rate is too fast.

[0070] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0071] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 2.8 L / min, the pivaloyl chloride addition rate is 1.33 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0072] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0073] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0074] Comparative Example 4

[0075] The difference between Comparative Example 4 and the solution of the present invention is that the liquid alkali is added too slowly.

[0076] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0077] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 2.6 L / min, the pivaloyl chloride addition rate is 1.33 L / min, the temperature is controlled below 30°C, stirring is performed for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0078] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0079] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0080] Comparative Example 5

[0081] The difference between Comparative Example 5 and the solution of the present invention is that the amount of liquid alkali is lower than the formula amount.

[0082] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 24 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 49 g of deionized water.

[0083] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0084] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0085] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0086] Comparative Example 6

[0087] The difference between Comparative Example 6 and the solution of the present invention is that the liquid alkali exceeds the formula amount.

[0088] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: t-amyl hydroperoxide (purity 90%) 15g, liquid caustic soda (purity 30%) 28g, pivaloyl chloride (purity 99%) 12g, and deionized water 44g.

[0089] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0090] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0091] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0092] Comparative Example 7

[0093] The difference between Comparative Example 7 and the solution of the present invention is that the acyl chloride is lower than the formula amount.

[0094] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 11 g of pivaloyl chloride (purity 99%), and 48 g of deionized water.

[0095] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0096] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0097] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0098] Comparative Example 8

[0099] The difference between Comparative Example 8 and the solution of the present invention is that the acyl chloride exceeds the formula amount.

[0100] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: t-amyl hydroperoxide (purity 90%) 15g, liquid caustic soda (purity 30%) 26g, pivaloyl chloride (purity 99%) 14g, and deionized water 45g.

[0101] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0102] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 3% PVA-4040, 20% methanol, 52% oil phase, and 24% deionized water.

[0103] The preparation method of the initiator emulsion is as follows: add SG-100, PVA-4040, methanol and deionized water into a reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0104] Comparative Example 9

[0105] In Comparative Example 9, no emulsifier was added.

[0106] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0107] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0108] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 3% PVA-4040, 20% methanol, 52% oil phase, and 25% deionized water.

[0109] The preparation method of the initiator emulsion is as follows: PVA-4040, methanol and deionized water are added to the reactor for mixing, stirring is started, the temperature is controlled below 0°C, stirring for 10 minutes and then transferred into the oil phase emulsification reactor, shearing is started after stirring for 10 minutes, and the preparation is completed after shearing for 30 minutes.

[0110] Comparative Example 10

[0111] In Comparative Example 10, no dispersant was added.

[0112] The raw materials for synthesizing t-amyl peroxy pivalate in this comparative example are: 15 g of t-amyl hydroperoxide (purity 90%), 26 g of liquid caustic soda (purity 30%), 12 g of pivaloyl chloride (purity 99%), and 47 g of deionized water.

[0113] The preparation method of tri-amyl peroxy pivalate is as follows: first, deionized water and tri-amyl hydrogen peroxide are added into a reaction kettle, stirring is started, the temperature is controlled below 30°C, and liquid alkali and pivaloyl chloride are added dropwise in a formula amount, the liquid alkali addition rate is 3.0 L / min, the pivaloyl chloride addition rate is 1.48 L / min, the temperature is controlled below 30°C, stirring for 5 minutes after the addition is completed, and the oil phase is prepared by standing to separate the water.

[0114] In this comparative example, the tri-pentyl peroxypivalate prepared as above is used to prepare its initiator emulsion, wherein the raw materials are prepared as follows: 1% SG-100, 20% methanol, 52% oil phase, and 27% deionized water.

[0115] The preparation method of the initiator emulsion is as follows: add SG-100, methanol and deionized water into the reactor and mix, start stirring, control the temperature below 0°C, stir for 10 minutes and then move into the oil phase emulsification reactor, start shearing after stirring for 10 minutes, and complete the preparation after shearing for 30 minutes.

[0116] The product indicators of the embodiments and comparative examples are as follows:

[0117]

[0118] At the same time, the embodiments involved in the present invention are all carried out on a 5L polymerization reactor for small-scale polymerization test verification and evaluation, and an SG-5 type PVC suspension polymerization experiment is carried out to evaluate the polymerization process parameters and PVC index data.

[0119] Product application indicators are as follows:

[0120]

[0121] The above shows and describes the basic principles and main features of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing pivalic acid peroxide, characterized in that: The method comprises the following steps: using water as a solvent, reacting t-amyl hydrogen peroxide with liquid alkali to generate t-amyl peroxide salt, and simultaneously reacting t-amyl peroxide salt with pivaloyl chloride to obtain t-amyl peroxy pivalate, wherein the speed of the substitution reaction of pivaloyl chloride is greater than the hydrolysis speed of pivaloyl chloride.

2. A method for preparing pivalic acid peroxide according to claim 1, characterized in that: First, t-amyl hydroperoxide is mixed with water, and then liquid alkali and pivaloyl chloride are added dropwise at the same time, and the dropping speed v1 of the liquid alkali is controlled to be greater than the dropping speed v2 of the pivaloyl chloride. After the dropping is completed, the t-amyl peroxy pivalate product is packaged after stirring and removing water, wherein v2=(0.492-0.494)*v1.

3. A method for preparing pivalic acid peroxide according to claim 2, characterized in that: The dropping speed v1 of the liquid caustic soda is 2.7 to 3.3 L / min, and the dropping speed v2 of the pivaloyl chloride is 1.33 to 1.63 L / min.

4. A method for preparing pivalic acid peroxide according to claim 3, characterized in that: The matching relationship between the dropping speed v1 of the liquid caustic soda and the dropping speed v2 of pivaloyl chloride is: v1=2.7L / min, v2=1.33L / min; or, v1=2.8L / min, v2=1.38L / min; or, v1=2.9L / min, v2=1.43L / min; or, v1=3.0L / min, v2=1.48L / min.

5. A method for preparing pivalic acid peroxide according to any one of claims 1 to 4, characterized in that: The concentration of the liquid alkali is 30%, and the concentration of the pivaloyl chloride is 99%.

6. A method for preparing pivalic acid peroxide according to claim 5, characterized in that: The temperature of the reaction system is kept below 30° C. during the mixing of tert-amyl hydroperoxide and water; and the temperature of the reaction system is kept below 35° C. during the dropwise addition of liquid alkali and pivaloyl chloride.

7. A method for preparing pivalic acid peroxide according to claim 5, characterized in that: The mass fractions of liquid alkali, p-amyl hydroperoxide, pivaloyl chloride and deionized water are:

8. A method for preparing a pivalic acid peroxy tri-pentyl ester initiator, characterized in that: The method comprises the following steps: dispersing auxiliary materials in an oil phase, and obtaining a tri-pentyl pivalate peroxide initiator after shearing and emulsification, wherein the auxiliary materials include an emulsifier, a dispersant, an antifreeze agent and water, and the oil phase is tri-pentyl pivalate peroxide obtained by any one of the preparation methods of claims 1 to 7.

9. A method for preparing a pivalic acid peroxy tri-pentyl ester initiator according to claim 8, characterized in that: During the process of dispersing the auxiliary materials in the oil phase, the temperature of the system is controlled below 0°C; the auxiliary materials are added to the oil phase and stirred for 10 minutes to be evenly dispersed; shear emulsification is carried out in an emulsifying kettle, and after stirring for 10 minutes, emulsification is carried out for 30 minutes.

10. A method for preparing a pivalate peroxy initiator according to claim 8, characterized in that: The mass fractions of oil phase and auxiliary materials are: The emulsifier is stearic acid polyoxyethylene ether; the dispersant is polyvinyl alcohol; the antifreeze agent is methanol, and the water is deionized water.

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