A poly(terphenyl) and its preparation method

Abstract

The present invention discloses a polyterphenyl and its preparation method, belonging to the technical field of polyterphenyl synthesis methods. The method includes: adding di-tert-butyl peroxide to diisopropylbenzene at a temperature of 130°C to 135°C for reaction until the weight-average molecular weight of the reaction solution obtained from the reaction is not less than 1850 and then stopping the reaction; precipitating the reaction solution after the reaction is stopped to obtain solid polyterphenyl. This method has simple operation, does not use highly active tert-butyl perbenzoate as an initiating promoter, has a low reaction temperature, no waste water or waste materials, and can be used for industrial production. The prepared polyterphenyl finished product has no variegated color, no peculiar smell, good state, and a relatively high molecular weight.

Description

Technical Field

[0001] The present invention relates to the technical field of the synthesis method of polycumene, and in particular, to a polycumene and a preparation method thereof. Background Art

[0002] Diisopropylbenzene oligomer, also known as polycumene, is an oligomer formed by sequentially connecting 4 to 7 diisopropylbenzene molecules. The carbon-carbon bond between quaternary carbon atoms in the polycumene molecule is not highly stable and is prone to dissociation to form free radicals. Based on this property, polycumene is widely used in cross-linking copolymerization catalysts and flame retardant synergists.

[0003] Compared with general free radical small molecule initiators, the structure of polycumene is more stable, the way of generating free radicals is more controllable, and it is safer to use. As a flame retardant synergist, it is widely used in bromine-based flame retardant systems and can be used to replace antimony trioxide to increase the flame retardant effect. The addition amount of polycumene is generally 2% - 3% of the flame retardant masterbatch. While reducing the amount of flame retardant used during use, it can also increase the mechanical properties of plastics.

[0004] Currently, the synthesis method of polycumene mainly uses peroxides to initiate diisopropylbenzene to form free radicals, and then the free radicals bond with each other to form polycumene molecules. In general synthesis, in order to increase the molecular weight of polycumene molecules, a small amount of highly active peroxides with a lower decomposition temperature (the most common is tert-butyl peroxybenzoate) is added to increase the reaction selectivity. Although the addition of highly active initiators can shorten the reaction time and reduce the reaction temperature, it will also make the obtained polycumene product yellowish and dull in color, affecting the appearance of the finished product; at the same time, the residual by-products such as benzoic acid generated during the reaction will also make the finished product have a strong odor and show softening and stickiness; the stability of the peroxybenzoyl group is also very poor, greatly increasing the safety hazards in the production process.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a polycumene and a preparation method thereof to solve or improve the above technical problems.

[0007] The present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a preparation method of polycumene, which includes the following steps: adding di-tert-butyl peroxide to diisopropylbenzene at a temperature of 130°C - 135°C and reacting until the weight average molecular weight of the reaction solution obtained from the reaction is not less than 1850 to stop the reaction; precipitating the reaction solution after the reaction stops to obtain solid polycumene.

[0009] In an alternative embodiment, the diisopropylbenzene is heated to 130°C - 135°C by an oil bath method.

[0010] In an alternative embodiment, adding di - tert - butyl peroxide to diisopropylbenzene at a temperature of 130 °C to 135 °C includes: first, dropping di - tert - butyl peroxide into diisopropylbenzene at a rate of 1 drop / s to 2 drops / s. When distillate starts to distill out, control the distillation rate of the distillate to be 10 drops / s to 20 drops / s by adjusting the dropping rate of di - tert - butyl peroxide and the oil bath temperature of diisopropylbenzene.

[0011] In an alternative embodiment, the actual reaction temperature during the reaction process does not exceed 125 °C.

[0012] In an alternative embodiment, after adding all of the di - tert - butyl peroxide, control the reaction temperature to be 118 °C to 123 °C.

[0013] In an alternative embodiment, the molar ratio of diisopropylbenzene to di - tert - butyl peroxide is from 1:1 to 1:2.

[0014] In an alternative embodiment, the precipitant used for precipitation includes at least one of ethanol and methanol.

[0015] In a second aspect, the present invention provides a polybiphenyl - terphenyl which is prepared by the preparation method according to any one of the foregoing embodiments;

[0016] The number - average molecular weight of the polybiphenyl - terphenyl is not less than 850;

[0017] The weight - average molecular weight of the polybiphenyl - terphenyl is not less than 1850;

[0018] The melting range of the polybiphenyl - terphenyl is 53 °C to 205 °C;

[0019] The polybiphenyl - terphenyl is a white solid powder.

[0020] The beneficial effects of the present invention include:

[0021] The present invention provides a new preparation method for polybiphenyl - terphenyl. This method is simple to operate, does not use highly active tert - butyl peroxybenzoate as an initiation promoter, has a low reaction temperature, a relatively high yield, no waste water or waste materials, and can be used for industrial production. The prepared polybiphenyl - terphenyl product has no variegated color, no peculiar smell, good state, and a relatively high molecular weight, and can be used for further preparing cross - linked copolymerization catalysts or flame - retardant synergists. Detailed Embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0023] The following is a detailed description of the polyol provided by the present invention and its preparation method.

[0024] The present invention provides a method for preparing polydioxane, which comprises the following steps: adding di-tert-butyl peroxide to diisopropylbenzene at a temperature of 130° C. to 135° C., reacting until the weight-average molecular weight of the reaction liquid obtained by the reaction is not less than 1850, and then stopping the reaction; and precipitating the reaction liquid after the reaction is stopped to obtain solid polydioxane.

[0025] The reaction principle is as follows: di-tert-butyl peroxide acts as a free radical initiator, which decomposes into tert-butyl radicals when heated; the tert-butyl radicals will attack diisopropylbenzene, seize the hydrogen of diisopropylbenzene, and turn diisopropylbenzene into diisopropylbenzene radicals. The diisopropylbenzene radicals bond with each other to form oligomer molecules with a degree of polymerization of 7 to 10, namely polyisopropylbenzene.

[0026] In the present invention, the molar ratio of diisopropylbenzene to di-tert-butyl peroxide can be 1:1 to 1:2, such as 1:1, 1:1.5 or 1:2, or other values within the range of 1:1 to 1:2.

[0027] In some embodiments, before adding di-tert-butyl peroxide, diisopropylbenzene may be heated to 130° C. to 135° C. to remove water.

[0028] The water removal time can be 2 hours, for example but not limited thereto.

[0029] By removing water from diisopropylbenzene, the effect of water on the decomposition of di-tert-butyl peroxide free radicals can be avoided.

[0030] In some embodiments, diisopropylbenzene may be heated to 130° C. to 135° C. in an oil bath. Specifically, the diisopropylbenzene oil bath temperature may be 130° C., 131° C., 132° C., 133° C., 134° C., or 135° C., or other values within the range of 130° C. to 135° C.

[0031] In some preferred embodiments, the reaction of adding di-tert-butyl peroxide to diisopropylbenzene at a temperature of 130° C. to 135° C. includes: first adding di-tert-butyl peroxide to diisopropylbenzene at a rate of 1 s / drop to 2 s / drop (such as 1 s / drop, 1.5 s / drop or 2 s / drop, etc.); when distillate begins to distillate, adjusting the dropping rate of di-tert-butyl peroxide and the oil bath temperature of diisopropylbenzene to control the distillation rate of the distillate to 10 s / drop to 20 s / drop (such as 10 s / drop, 12 s / drop, 14 s / drop, 16 s / drop, 18 s / drop or 20 s / drop, etc.).

[0032] The above diisopropylbenzene is in a stirring state.

[0033] By controlling the order of adding di-tert-butyl peroxide in stages, it is possible to ensure a moderate reaction rate while also avoiding raw material waste. If the addition of di-tert-butyl peroxide is accelerated too quickly, the reaction system temperature will drop rapidly, reducing the reaction rate. Furthermore, a large amount of di-tert-butyl peroxide will accumulate in the reaction vessel, posing a risk of implosion and a significant safety hazard. If the addition of di-tert-butyl peroxide is accelerated too slowly, the temperature in the reaction vessel will be too high, causing a large amount of di-tert-butyl peroxide to evaporate without participating in the reaction, resulting in raw material waste.

[0034] In the present invention, the actual reaction temperature of the reaction of diisopropylbenzene and di-tert-butyl peroxide does not exceed 125° C. In some preferred embodiments, after the addition of di-tert-butyl peroxide is completed, the reaction temperature is controlled to be 118° C. to 123° C., such as 118° C., 119° C., 120° C., 121° C., 122° C., or 123° C., or any other value within the range of 118° C. to 123° C.

[0035] The reaction time can be, for example, 15 to 22 hours, such as 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours or 22 hours, etc., depending on the actual situation.

[0036] The reaction can be stopped when the weight-average molecular weight of the resulting reaction solution is no less than 1850. Under these conditions, the reaction solution is as viscous as honey, and the mass fraction of di-tert-butyl peroxide in the distillate is less than 1 / 3. If the reaction solution has a low viscosity and the weight-average molecular weight of the reaction solution is less than 1850, or the di-tert-butyl peroxide content in the distillate exceeds one-third, additional di-tert-butyl peroxide can be added to continue the reaction until the weight-average molecular weight of the reaction solution reaches no less than 1850.

[0037] After the reaction stops, the reaction solution can be poured into a precipitant while hot to precipitate to obtain white solid particles, which are then filtered and dried at room temperature to obtain the polycondensate product.

[0038] Alternatively, the precipitant may illustratively but not limitatively include at least one of ethanol and methanol.

[0039] In some preferred embodiments, the yield of the preparation method of polydimethylsilane provided by the present invention is not less than 90%.

[0040] As mentioned above, the preparation method of poly-bis(cyclopentyl)ol provided by the present invention is simple to operate. It does not use highly active tert-butyl perbenzoate as an initiator and accelerator. Instead, it achieves a stable increase in the molecular weight of the poly-bis(cyclopentyl)ol by precisely controlling the material dropwise addition rate and temperature during the reaction. The process has a low reaction temperature, a high yield, and no wastewater or waste, and can be used for industrial production.

[0041] Correspondingly, the present invention also provides a polyol, which is prepared by the above preparation method.

[0042] The resulting poly(terphenyl) product has a relatively high molecular weight, is white in color, does not turn yellow or darken, and has no variegated colors; moreover, the poly(terphenyl) has no peculiar smell, is in solid state, in good condition, and does not show the phenomenon of softening and sticking.

[0043] In some embodiments, the number-average molecular weight of the poly(terphenyl) provided by the present invention is not less than 850, and can be, for example, 810, 890, 940, 1100, 1610, etc.

[0044] In some embodiments, the weight-average molecular weight of the poly(terphenyl) provided by the present invention is not less than 1850, and can be, for example, 1850, 2070, 2100, 3200, 4540, etc.

[0045] In some embodiments, the melting range of the poly(terphenyl) provided by the present invention can be 53°C to 205°C, and can be, for example, 53.7°C to 196.0°C, 57.8°C to 199.6°C, 60.1°C to 201.1°C, 61.1°C to 188.2°C, 70.4°C to 204.0°C, etc.

[0046] In addition, the present invention also provides an application of the above poly(terphenyl), for example, the poly(terphenyl) can be used to prepare a crosslinked copolymerization catalyst or a flame retardant synergist.

[0047] The features and properties of the present invention will be further described in detail below in conjunction with examples.

[0048] Example 1

[0049] This example provides a method for preparing poly(terphenyl), which includes the following steps:

[0050] S1: Add 81.2 g of diisopropylbenzene into the reaction flask, insert a thermometer, start mechanical stirring, set the oil bath temperature to 133°C, and remove water for 2 h.

[0051] S2: After the water removal is completed, slowly drop di-tert-butyl peroxide using a constant pressure dropping funnel at a dropping rate of about 1 drop / s. When distillate starts to distill out, control the oil bath temperature and the dropping rate so that the distillate distills out at a rate of 10 drops / s, and the actual temperature of the reaction solution is 123°C.

[0052] S3: After all the di-tert-butyl peroxide (the molar ratio of diisopropylbenzene to di-tert-butyl peroxide is 1:2) is dropped, keep the internal temperature at 123°C for a holding reaction, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction process.

[0053] S4: After reacting for 15 h, the reaction solution is viscous like honey. At this time, the weight-average molecular weight of the reaction solution is 2070, and stop the reaction. While it is hot, pour the reaction solution into ethanol for precipitation to obtain white solid particles, filter by suction, and dry at room temperature to obtain the poly(terphenyl) product.

[0054] Example 2

[0055] This example provides a preparation method of polybiphenyl, which includes the following steps:

[0056] S1: Add 81.7 g of diisopropylbenzene into the reaction flask, insert a thermometer, turn on the mechanical stirrer, set the oil bath temperature to 134 °C, and remove water for 2 h.

[0057] S2: After the water removal is completed, slowly dropwise add di-tert-butyl peroxide using a constant pressure dropping funnel at a dropping rate of about 1 drop / s. When the distillate starts to distill out, control the oil bath temperature and the dropping rate so that the distillate distills out at a rate of 10 drops / s, and the actual temperature of the reaction solution is 121 °C.

[0058] S3: Wait until all the di-tert-butyl peroxide (the molar ratio of diisopropylbenzene to di-tert-butyl peroxide is 1:1.5) is completely dropped, control the internal temperature to keep the reaction at 121 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0059] S4: After reacting for 21 h, the reaction solution is viscous like honey. At this time, the weight average molecular weight of the reaction solution is 3200, and stop the reaction. Pour the reaction solution into ethanol while it is hot for precipitation to obtain white solid particles, filter by suction, and dry at room temperature to obtain the polybiphenyl product.

[0060] Example 3

[0061] This example provides a preparation method of polybiphenyl, which includes the following steps:

[0062] S1: Add 83.7 g of diisopropylbenzene into the reaction flask, insert a thermometer, turn on the mechanical stirrer, set the oil bath temperature to 131 °C, and remove water for 2 h.

[0063] S2: After the water removal is completed, slowly dropwise add di-tert-butyl peroxide using a constant pressure dropping funnel at a dropping rate of about 1 drop / s. When the distillate starts to distill out, control the oil bath temperature and the dropping rate so that the distillate distills out at a rate of 10 drops / s, and the actual temperature of the reaction solution is 121 °C.

[0064] S3: Wait until all the di-tert-butyl peroxide (the molar ratio of diisopropylbenzene to di-tert-butyl peroxide is 1:1.8) is completely dropped, control the internal temperature to keep the reaction at 119 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0065] S4: After reacting for 21 h, the reaction solution is viscous like honey. At this time, the weight average molecular weight of the reaction solution is 1850, and stop the reaction. Pour the reaction solution into ethanol while it is hot for precipitation to obtain white solid particles, filter by suction, and dry at room temperature to obtain the polybiphenyl product.

[0066] Example 4

[0067] This embodiment provides a preparation method of polybenzylidene, including the following steps:

[0068] S1: Add 80.6 g of diisopropylbenzene into the reaction flask, insert a thermometer, turn on the mechanical stirrer, set the oil bath temperature to 132 °C, and remove water for 2 h.

[0069] S2: After the water removal is completed, slowly drip di-tert-butyl peroxide using a constant pressure dropping funnel at a dropping rate of about 2 s / drop. When distillate starts to distill out, control the oil bath temperature and dropping rate so that the distillate distills out at a rate of 15 s / drop, and the actual temperature of the reaction liquid is 124 °C.

[0070] S3: Wait until all of the di-tert-butyl peroxide (the molar ratio of diisopropylbenzene to di-tert-butyl peroxide is 1:1.3) is dropped, control the internal temperature to keep the reaction at 121 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0071] S4: After reacting for 19 h, the reaction liquid is viscous like honey. At this time, the weight average molecular weight of the reaction liquid is 2100, and stop the reaction. While it is hot, pour the reaction liquid into ethanol for precipitation to obtain white solid particles, perform suction filtration, and dry at room temperature to obtain the polybenzylidene product.

[0072] Example 5

[0073] This embodiment provides a preparation method of polybenzylidene, including the following steps:

[0074] S1: Add 83.2 g of diisopropylbenzene into the reaction flask, insert a thermometer, turn on the mechanical stirrer, set the oil bath temperature to 134 °C, and remove water for 2 h.

[0075] S2: After the water removal is completed, slowly drip di-tert-butyl peroxide using a constant pressure dropping funnel at a dropping rate of about 2 s / drop. When distillate starts to distill out, control the oil bath temperature and dropping rate so that the distillate distills out at a rate of 16 s / drop, and the actual temperature of the reaction liquid is 125 °C.

[0076] S3: Wait until all of the di-tert-butyl peroxide (the molar ratio of diisopropylbenzene to di-tert-butyl peroxide is 1:1.7) is dropped, control the internal temperature to keep the reaction at 119 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0077] S4: After reacting for 19 h, the reaction liquid is viscous like honey. At this time, the weight average molecular weight of the reaction liquid is 4540, and stop the reaction. While it is hot, pour the reaction liquid into ethanol for precipitation to obtain white solid particles, perform suction filtration, and dry at room temperature to obtain the polybenzylidene product.

[0078] Comparative Example 1

[0079] This comparative example provides a preparation method of polybenzylidene, including the following steps:

[0080] S1: Add 85.1 g of diisopropylbenzene into the reaction flask, insert the thermometer, start the mechanical stirring, set the oil bath temperature at 133 °C, and remove water for 2 h.

[0081] S2: After the water removal is completed, slowly add dropwise the peroxide mixture composed of di-tert-butyl peroxide and tert-butyl perbenzoate (in the peroxide mixture, the amount of tert-butyl perbenzoate is 38.9 wt%) using a constant pressure dropping funnel at a dropping rate of about 2 drops / s. When the distillate starts to distill out, control the oil bath temperature and the dropping rate so that the distillate distills out at a rate of 15 drops / s, and the actual reaction solution temperature is 125 °C.

[0082] S3: Wait until the peroxide mixture (the molar ratio of diisopropylbenzene to the peroxide mixture is 1:1.5) is completely added dropwise, control the internal temperature to keep the reaction at 119 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0083] S4: After reacting for 15 h, at this time the weight average molecular weight of the reaction solution is 2670, stop the reaction. While it is hot, pour the reaction solution into ethanol for precipitation to obtain yellow solid particles with a benzoic acid smell, filter by suction, and dry at room temperature to obtain the polybiphenylene product.

[0084] Comparative Example 2

[0085] This comparative example provides a preparation method of polybiphenylene, including the following steps:

[0086] S1: Add 83.7 g of diisopropylbenzene into the reaction flask, insert the thermometer, start the mechanical stirring, set the oil bath temperature at 135 °C, and remove water for 2 h.

[0087] S2: After the water removal is completed, slowly add dropwise the peroxide mixture composed of di-tert-butyl peroxide and tert-butyl perbenzoate (in the peroxide mixture, the amount of tert-butyl perbenzoate is 19.9 wt%) using a constant pressure dropping funnel at a dropping rate of about 2 drops / s. When the distillate starts to distill out, control the oil bath temperature and the dropping rate so that the distillate distills out at a rate of 12 drops / s, and the actual reaction solution temperature is 124 °C.

[0088] S3: Wait until the peroxide mixture (the molar ratio of diisopropylbenzene to the peroxide mixture is 1:1.8) is completely added dropwise, control the internal temperature to keep the reaction at 120 °C, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction progress.

[0089] S4: After reacting for 17 h, at this time the weight average molecular weight of the reaction solution is 980, stop the reaction. While it is hot, pour the reaction solution into ethanol for precipitation to obtain yellow waxy solid particles with a benzoic acid smell, filter by suction, and dry at room temperature to obtain the polybiphenylene product.

[0090] Comparative Example 3

[0091] This comparative example provides a method for preparing polyphenylenes, comprising the following steps:

[0092] S1: Add 81.0 g of diisopropylbenzene into a reaction flask, insert a thermometer, start mechanical stirring, set the oil bath temperature at 133 °C, and remove water for 2 h.

[0093] S2: After water removal, slowly drip a peroxide mixture composed of di-tert-butyl peroxide and tert-butyl perbenzoate (in the peroxide mixture, the amount of tert-butyl perbenzoate is 30.3 wt%) using a constant pressure dropping funnel at a dropping rate of about 1 drop / s. When distillate starts to distill out, control the oil bath temperature and dropping rate so that the distillate distills out at a rate of 13 drops / s, and the actual temperature of the reaction solution is 123 °C.

[0094] S3: After all the peroxide mixture (the molar ratio of diisopropylbenzene to the peroxide mixture is 1:2) is dripped, keep the internal temperature at 123 °C for heat preservation reaction, and take samples every 2 h to measure gas chromatography and GPC to monitor the reaction process.

[0095] S4: After reacting for 20 h, at this time the weight average molecular weight of the reaction solution is 1160, stop the reaction. While it is hot, pour the reaction solution into ethanol for precipitation to obtain yellow waxy solid particles with a benzoic acid smell, filter by suction, and dry at room temperature to obtain the polyphenylene product.

[0096] Comparative Example 4

[0097] The difference between this comparative example and Example 1 is that in S2, when distillate starts to distill out, by adjusting the dropping rate of di-tert-butyl peroxide and the oil bath temperature of diisopropylbenzene, control the distillate distilling rate at 5 drops / s.

[0098] Comparative Example 5

[0099] The difference between this comparative example and Example 1 is that in S2, when distillate starts to distill out, by adjusting the dropping rate of di-tert-butyl peroxide and the oil bath temperature of diisopropylbenzene, control the distillate distilling rate at 25 drops / s.

[0100] Comparative Example 6

[0101] The difference between this comparative example and Example 1 is that in S2, the actual reaction temperature during the reaction process is 130 °C.

[0102] Comparative Example 7

[0103] The difference between this comparative example and Example 1 is that in S3, keep the internal temperature at 127 °C for heat preservation reaction.

[0104] Comparative Example 8

[0105] The difference between this comparative example and Example 1 is that in S4, the reaction time is 10 h.

[0106] Test Example

[0107] Examples 1-5 and Comparative Examples 1-8 were each repeated 3 times, and the polywithered branches prepared in Examples 1-5 and Comparative Examples 1-8 were compared. The results are shown in Table 1, and the data in Table 1 are the average results of 3 times.

[0108] Table 1 Comparison Results

[0109]

[0110] It can be seen from Table 1 that the polybiphenyl withered prepared in the examples of the present invention can have better color and product state and higher yield compared with the polybiphenyl withered prepared in Comparative Examples 1-8.

[0111] In summary, by strictly controlling the reaction temperature and dropping rate during the reaction process, the present invention avoids the waste of raw materials caused by excessive evaporation of di-tert-butyl peroxide above its boiling point without adding an initiator promoter. The reaction conversion rate of this method is relatively high, and the yield can reach more than 90%. Compared with the reaction using tert-butyl peroxybenzoate as the reaction selection promoter, the product has a clean color without variegation, no peculiar smell, and good state.

[0112] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of polybiphenyl, characterized in that, Comprising the following steps: Heat diisopropylbenzene to 130°C - 135°C by means of an oil bath, add di-tert-butyl peroxide to the diisopropylbenzene at a temperature of 130°C - 135°C and react until the weight-average molecular weight of the reaction solution obtained from the reaction is not less than 1850 to stop the reaction; precipitate the reaction solution after the reaction stops to obtain solid poly(diisopropylbenzene); Adding di-tert-butyl peroxide to the diisopropylbenzene at a temperature of 130°C - 135°C for reaction includes: first, dropwise add the di-tert-butyl peroxide to the diisopropylbenzene at a rate of 1 drop / s - 2 drops / s. When distillate starts to distill out, control the distillation rate of the distillate to be 10 drops / s - 20 drops / s by adjusting the dropping rate of the di-tert-butyl peroxide and the oil bath temperature of the diisopropylbenzene; The actual reaction temperature during the reaction process does not exceed 125°C; After adding all of the di-tert-butyl peroxide, control the reaction temperature to be 118°C - 123°C; The molar ratio of the diisopropylbenzene to the di-tert-butyl peroxide is 1:1 to 1:2; The precipitating agent used for precipitation includes at least one of ethanol and methanol.

Images