A method for preparing a single-structure p-chloromethylstyrene

Abstract

This invention relates to the field of fine chemical intermediates, specifically to a method for preparing a single-structure p-chloromethylstyrene, comprising the following steps: S1: 1-(1-chloroethyl)-4-(chloromethyl)benzene is dissolved in tert-butanol under an inert gas atmosphere, cooled to 10-15 °C, and then alkali is added in batches under vigorous stirring, maintaining the reaction system temperature between 10-15 °C; S2: After the alkali is added, the reaction is continued to be vigorously stirred at 10-15 °C for 1-4 h, with ultrasonic treatment every 7-15 s followed by standing for 20-30 s; after the reaction is completed, p-chloromethylstyrene is obtained through post-processing. This invention, based on the substrate structure, achieves precise and specific localization of the chloromethyl group at the para-position of the vinyl group, resulting in a product free of ortho-isomers and with a high overall yield.

Description

Technical Field

[0001] This invention relates to the field of fine chemical intermediates technology, specifically to a method for preparing a single-structure p-chloromethylstyrene. Background Technology

[0002] p-Chloromethylstyrene is an important organic synthesis intermediate widely used in functional polymer materials (such as ion exchange resins and adsorbents), drug synthesis, pesticide intermediates, and the preparation of high-end fine chemicals such as semiconductors and photoresists. The chloromethyl group in its structure exhibits high reactivity and can be further functionalized, thus holding significant value in polymer modification and molecular construction.

[0003] Currently, there are several methods for synthesizing chloromethylstyrene: 1) Styrene is obtained by chloromethylation with chloromethyl ether under Lewis acid catalysis (Polymer, 1973, 14(7): 330-332.); 2) Ethylbenzene is chloromethylated with chloromethyl ether, followed by halogenation and dehydrohalogenation to obtain the product (US, 2780604[P]. 1957-02-05.); 3) p-Methylbenzocyanine is successively chlorinated, reduced twice, and dehydrated to generate the target product (Journal of the Chemical Society, 1962: 1515-1516.); 4) 2-Phenylacetane is synthesized by chloromethylation with chloromethyl ether or blanc reaction and dehydrobromination (Synthetic Communications, 1974, 4(4): 193-197.; Journal of Molecular Catalysis A: Chemical, 2007, 277: 113-118.);5)Toluene and ethylbenzene are obtained by high-temperature chlorination and dehydrogenation reaction (Chemical Industry Times, 2001, 15(2): 25-26.).

[0004] However, traditional methods suffer from the following significant problems: Poor regioselectivity: Conventional chloromethylation reactions often result in the formation of a mixture of ortho and para-chloromethyl groups, making it difficult to achieve high selectivity in the preparation of the para-product. Commercially available p-chloromethylstyrene is usually an ortho-para mixture, severely impacting its application in precision synthesis. Purification of ortho-para mixtures is difficult: Due to the similar physicochemical properties of the ortho and para isomers, separation and purification are challenging and costly, resulting in product purity that fails to meet the demands of high-end applications. Furthermore, the synthesis of p-chloromethylstyrene requires harsh reaction conditions: Some methods involve highly toxic reagents (such as chloromethyl ether), highly corrosive media, or high-temperature and high-pressure conditions, posing safety and environmental risks. Summary of the Invention

[0005] This invention addresses the problems of poor regioselectivity and low product purity in the synthesis of p-chloromethylstyrene in the prior art by providing a method for preparing p-chloromethylstyrene with a single structure. The method of this invention is based on the substrate structure and achieves precise and specific positioning of chloromethyl at the para position of vinyl groups. The product does not contain ortho isomers and has a high overall yield.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a single-structure p-chloromethylstyrene, characterized by comprising the following steps: S1: Dissolve 1-(1-chloroethyl)-4-(chloromethyl)benzene in tert-butanol under inert gas protection, cool to 10~15 ℃, and then add alkali in batches under vigorous stirring, maintaining the temperature of the reaction system between 10~15 ℃; S2: After the alkali is added, the reaction is continued to be vigorously stirred at 10~15 ℃ for 1~4 h. During vigorous stirring, the mixture is sonicated for 7~15 s and then allowed to stand for 20~30 s. After the reaction is completed, p-chloromethylstyrene is obtained through post-treatment.

[0007] Its chemical reaction formula is shown in formula (1).

[0008] Equation (1) Preferably, the alkali is at least one selected from potassium tert-butoxide, sodium tert-butoxide, sodium methoxide, and sodium ethoxide.

[0009] Preferably, the alkali is at least one of potassium tert-butoxide and sodium tert-butoxide.

[0010] Preferably, the molar ratio of the base to 1-(1-chloroethyl)-4-(chloromethyl)benzene is 1.05 to 1.7:1.

[0011] Preferably, the speed of the vigorous stirring is 700~1500 rpm.

[0012] Preferably, the power of the ultrasonic treatment is 100~200 W.

[0013] Preferably, the mass-to-volume ratio of 1-(1-chloroethyl)-4-(chloromethyl)benzene to tert-butanol is 1 mol: 800~1200 ml.

[0014] Preferably, the post-processing includes the following steps: pouring the reaction solution into ice water, then extracting it multiple times with n-hexane, combining the organic phases, washing with deionized water, drying the washed organic phase with anhydrous magnesium sulfate, filtering, recovering n-hexane by vacuum distillation of the filtrate using a water pump, and then collecting the fraction at 70-80 °C by vacuum distillation using an oil pump to obtain the colorless and transparent liquid product p-chloromethylstyrene.

[0015] Preferably, the inert gas is one of nitrogen or argon.

[0016] The beneficial effects of this invention are: This invention uses 1-(1-chloroethyl)-4-(chloromethyl)benzene as the starting material. By controlling the reaction temperature at 10-15°C, the thermally induced polymerization of p-chloromethylstyrene is significantly suppressed, byproducts are reduced, and product purity and yield are improved. Furthermore, the cavitation and mechanical effects of ultrasonic treatment are utilized to enhance mass transfer and promote the elimination reaction. Simultaneously, a low-temperature environment is maintained by preventing continuous heat accumulation during the settling period. Vigorous stirring and intermittent ultrasonic treatment synergistically achieve highly efficient reactions at low temperatures. The use of tert-butanol as a solvent, with its high steric hindrance, allows for more effective guidance of the elimination pathway at low temperatures.

[0017] The method of this invention is based on the substrate structure and achieves precise and specific localization of chloromethyl at the para position of vinyl groups. The product does not contain ortho isomers, which perfectly solves the fundamental problem that the product of traditional methods is a mixture. High-purity products can be obtained by simple distillation. The prepared p-chloromethylstyrene has high yield and high purity, avoids complicated chromatographic separation, and reduces production costs. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: It was determined that, at the mass-to-volume ratio of 1-(1-chloroethyl)-4-(chloromethyl)benzene to tert-butanol (1 mol : 800~1200 ml), the freezing point of the mixed solution was below 5°C. Therefore, at a reaction temperature of 10~15°C, the reaction system remained in a homogeneous liquid state and could be subjected to vigorous stirring and ultrasonic treatment normally.

[0020] In a 250 mL three-necked flask equipped with a stirrer and thermometer, 30.6 g (0.162 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of anhydrous tert-butanol under nitrogen protection. The reaction solution was cooled to 15 °C, and potassium tert-butoxide (20.2 g, 0.18 mol) solid was added in portions with vigorous stirring (1000 rpm), controlling the addition rate to maintain the temperature of the reaction system between 10 and 15 °C.

[0021] After potassium tert-butoxide was added, the mixture was stirred vigorously at 10-15 °C (1000 rpm) for 1.5 h, with ultrasonic treatment every 12 s followed by 25 s. The ultrasonic power was 150 W. After the reaction was complete, the reaction solution was poured into 200 mL of ice water and extracted with n-hexane (80 mL × 3). The organic phases were combined and washed with deionized water (100 mL × 2). The obtained organic phase was dried over anhydrous magnesium sulfate, filtered, and the filtrate was first distilled under reduced pressure using a water pump in a 40 °C water bath to recover n-hexane. Then, the fraction was collected under reduced pressure using an oil pump at 70-80 °C to obtain 22.25 g of a colorless, transparent liquid product, p-chloromethylstyrene, with a yield of 90.1% and a purity of 99.5%. 1 H NMR (CDCl3, 400 MHz, δ ppm), 7.39-7.32 (m, 4H), 6.72 (dd, 1H), 5.79 (d, 1H), 5.29 (d, 1H), 4.48 (s, 2H); 13 C NMR (100 MHz, CDCl3, δ ppm) 137.7, 137.2, 136.2, 129.3, 126.6, 114.6, 33.5. GC-MS: m / z[M] + 152.1, theoretical value: 152.04. Example 2: In a 250 mL three-necked flask equipped with a stirrer and a thermometer, 29.5 g (0.156 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of anhydrous tert-butanol under nitrogen protection. The reaction solution was cooled to 12 °C, and sodium tert-butoxide (23.07 g, 0.24 mol) solid was added in portions under vigorous stirring (1000 rpm). The addition rate was controlled to maintain the temperature of the reaction system between 10 and 15 °C.

[0022] After sodium tert-butoxide was added, the mixture was stirred vigorously at 10-15 °C (1000 rpm) for 3 hours, with ultrasonic treatment every 8 seconds followed by 25 seconds. The ultrasonic power was 150W. After the reaction was complete, the reaction solution was poured into 200 mL of ice water and extracted with n-hexane (80 mL × 3). The organic phases were combined and washed with deionized water (100 mL × 2). The obtained organic phase was dried over anhydrous magnesium sulfate, filtered, and the filtrate was first distilled under reduced pressure using a water pump in a 40 °C water bath to recover n-hexane. Then, the fraction was collected under reduced pressure using an oil pump at 70-80 °C to obtain 21.5 g of a colorless, transparent liquid product, p-chloromethylstyrene, with a yield of 90.3% and a purity of 99.3%.

[0023] Example 3: In a 250 mL three-necked flask equipped with a stirrer and a thermometer, 30.6 g (0.162 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of anhydrous tert-butanol under nitrogen protection. The reaction solution was cooled to 12 °C, and sodium methoxide (9.72 g, 0.18 mol) solid was added in portions under vigorous stirring (1000 rpm). The addition rate was controlled to maintain the temperature of the reaction system between 10 and 15 °C.

[0024] After sodium methoxide was added, the mixture was stirred vigorously at 10-15 °C (1000 rpm) for 2 h. During vigorous stirring, the mixture was sonicated for 10 s, followed by a 20 s settling period. The sonication power was 150 W. After the reaction, post-treatment was performed as in Example 1, yielding 21.9 g of p-chloromethylstyrene, with a yield of 88.7% and a purity of 99.1%.

[0025] Example 4: In a 250 mL three-necked flask equipped with a stirrer and thermometer, 30.6 g (0.162 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of anhydrous tert-butanol under nitrogen protection. The reaction solution was cooled to 10 °C, and sodium ethoxide (12.3 g, 0.18 mol) was added in portions with vigorous stirring (1200 rpm), controlling the addition rate to maintain the temperature of the reaction system between 10 and 15 °C.

[0026] After sodium ethoxide was added, the mixture was stirred vigorously at 10-15 °C (1200 rpm) for 2.5 h. During vigorous stirring, the mixture was sonicated for 15 s followed by a 30 s settling period. The sonication power was 120 W. After the reaction, post-processing was performed as in Example 1, yielding 21.6 g of p-chloromethylstyrene, with a yield of 87.5% and a purity of 98.9%.

[0027] Example 5: In a 250 mL three-necked flask equipped with a stirrer and thermometer, 30.6 g (0.162 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of tert-butanol under nitrogen protection. The reaction solution was cooled to 10 °C, and potassium tert-butoxide (19.1 g, 0.17 mol) was added in portions with vigorous stirring (1000 rpm), controlling the addition rate to maintain the temperature of the reaction system between 10 and 15 °C.

[0028] After potassium tert-butoxide was added, the mixture was stirred vigorously at 10-15 °C (1000 rpm) for 1.5 h, with ultrasonic treatment every 12 s followed by a 25 s settling period. The ultrasonic power was 150 W. After the reaction, post-treatment was performed as in Example 1, yielding 20.8 g of p-chloromethylstyrene, with a yield of 84.2% and a purity of 99.3%.

[0029] Example 6: In a 250 mL three-necked flask equipped with a stirrer and thermometer, 30.6 g (0.162 mol) of 1-(1-chloroethyl)-4-(chloromethyl)benzene was dissolved in 150 mL of tert-butanol under nitrogen protection. The reaction solution was cooled to 10 °C, and potassium tert-butoxide (30.9 g, 0.275 mol) was added in portions with vigorous stirring (1000 rpm), controlling the addition rate to maintain the temperature of the reaction system between 10 and 15 °C.

[0030] After potassium tert-butoxide was added, the mixture was stirred vigorously at 10-15 °C (1000 rpm) for 1.5 h, with ultrasonic treatment every 12 s followed by a 25 s settling period. The ultrasonic power was 150 W. After the reaction, post-treatment was performed as in Example 1, yielding 22.1 g of p-chloromethylstyrene with a yield of 89.5% and a purity of 99.0%.

[0031] Example 7: Other conditions were the same as in Example 1, except that the stirring speed was adjusted to 700 rpm. 21.5 g of p-chloromethylstyrene was obtained, with a yield of 87.1% and a purity of 98.8%.

[0032] Example 8: Other conditions were the same as in Example 1, except that the stirring speed was adjusted to 1500 rpm. 22.4 g of p-chloromethylstyrene was obtained, with a yield of 90.7% and a purity of 99.4%.

[0033] Example 9: Other conditions were the same as in Example 1, except that the ultrasonic power was adjusted to 100 W. 21.7 g of the product p-chloromethylstyrene was obtained, with a yield of 87.9% and a purity of 98.7%.

[0034] Example 10: Other conditions were the same as in Example 1, except that the ultrasonic power was adjusted to 200 W. 22.3 g of the product p-chloromethylstyrene was obtained, with a yield of 90.3% and a purity of 99.2%.

[0035] Example 11: 1-(1-chloroethyl)-4-(chloromethyl)benzene (30.6 g, 0.162 mol) was dissolved in 130 mL of anhydrous tert-butanol under the same conditions as in Example 1. 21.9 g of the product p-chloromethylstyrene was obtained, with a yield of 88.7% and a purity of 99.0%.

[0036] Example 12: 1-(1-chloroethyl)-4-(chloromethyl)benzene (30.6 g, 0.162 mol) was dissolved in 195 mL of anhydrous tert-butanol under the same conditions as in Example 1. 22.0 g of the product p-chloromethylstyrene was obtained, with a yield of 89.1% and a purity of 99.2%.

[0037] Example 13: Other conditions were the same as in Example 1, except that nitrogen was replaced with argon. 22.3 g of the product p-chloromethylstyrene was obtained, with a yield of 90.3% and a purity of 99.5%.

[0038] Comparative Example 1: Unlike Example 1, when adding potassium tert-butoxide solid, the addition rate was controlled to maintain the reaction system temperature between 20 and 25 °C; after the potassium tert-butoxide was added, the reaction was continued to be vigorously stirred (at a speed of 1000 rpm) at 20 to 25 °C for 1.5 h.

[0039] The final product was a colorless and transparent liquid product, p-chloromethylstyrene, weighing 21.80 g, with a yield of 88.3% and a purity of 96.7%.

[0040] Comparative Example 2: Unlike Example 1, when adding potassium tert-butoxide solid, the addition rate was controlled to maintain the reaction system temperature between 4 and 8°C; after the potassium tert-butoxide was added, the reaction was continued to be vigorously stirred (at a speed of 1000 rpm) at 4 to 8°C for 1.5 h.

[0041] The final product was a colorless and transparent liquid p-chloromethylstyrene, weighing 18.98 g, with a yield of 76.8% and a purity of 98.3%.

[0042] Comparative Example 3: Unlike Example 1, ultrasonic treatment was not performed during vigorous stirring after potassium tert-butoxide was added.

[0043] The final product was a colorless and transparent liquid p-chloromethylstyrene, weighing 19.88 g, with a yield of 80.4% and a purity of 98.2%.

[0044] Comparative Example 4: Unlike Example 1, after potassium tert-butoxide was added, the mixture was vigorously stirred and ultrasonically treated for 25 seconds, followed by a 25-second settling period. The final product was a colorless and transparent liquid product, p-chloromethylstyrene, weighing 22.05 g, with a yield of 89.3% and a purity of 96.8%.

[0045] Comparative Example 5: Unlike Example 1, vigorous stirring was replaced with normal stirring at a speed of 300 rpm.

[0046] The final product was a colorless and transparent liquid p-chloromethylstyrene, weighing 21.38 g, with a yield of 86.6% and a purity of 97.5%.

[0047] Comparative Example 6: Other conditions were the same as in Example 3, but the reaction temperature was maintained at 25-30 °C. 19.8 g of the product p-chloromethylstyrene was obtained, with a yield of 80.2% and a purity of 94.5%.

[0048] Comparative Example 7: Other conditions were the same as in Example 4, but the amount of alkali used was 0.324 mol. 20.5 g of the product p-chloromethylstyrene was obtained, with a yield of 83.0% and a purity of 95.2%.

[0049] Comparative Example 8: Other conditions were the same as in Example 1, but the stirring speed was 180 rpm. 20.2 g of p-chloromethylstyrene was obtained, with a yield of 81.8% and a purity of 96.0%.

[0050] Comparative Example 9: Other conditions were the same as in Example 1, but the ultrasonic power was 300 W. 21.0 g of the product p-chloromethylstyrene was obtained, with a yield of 85.0% and a purity of 94.8%.

[0051] Comparative Example 10: Other conditions were the same as in Example 1, except that 1-(1-chloroethyl)-4-(chloromethyl)benzene (30.6 g, 0.162 mol) was dissolved in 81 mL of anhydrous tert-butanol. The product, p-chloromethylstyrene, was obtained in 19.5 g, with a yield of 79.0% and a purity of 95.5%.

[0052] The comparison of the conditions and results between the examples and the comparative examples is shown in Table 1.

[0053] Table 1:

[0054] Comparison Result Analysis: Comparing Example 1 with Comparative Examples 1 and 2, it can be seen that when the reaction temperature is too high (20~25℃), the purity decreases significantly (96.7%), and the yield decreases slightly (88.3%). When the temperature is too low (4~8℃), the yield decreases sharply (76.8%), and the purity also decreases slightly. Therefore, the optimal temperature range is 10~15℃, which can balance high yield (>90%) and high purity (>99%).

[0055] Comparing Example 1 with Comparative Examples 3 and 4, it can be seen that without ultrasonic treatment, the yield drops to 80.4% and the purity to 98.2%, indicating that ultrasonication significantly promotes the reaction. However, if the single ultrasonic treatment time is too long (25s), the purity drops to 96.8%, which may lead to side reactions due to local overheating. Therefore, the preferred ultrasonic mode is: after every 7-15s of ultrasonication, allow it to stand for 20-30s, as shown in Example 1 (12s / 25s) and Example 2 (8s / 25s).

[0056] Comparing Examples 1, 7, and 8 with Comparative Examples 5 and 8, it can be seen that at excessively low rotation speeds (300 rpm and 180 rpm), the yields decreased to 86.6% and 81.8%, respectively, and the purity also decreased. Good results can be obtained at rotation speeds of 700–1500 rpm, with the best results achieved at 1000–1500 rpm.

[0057] Comparing Examples 1-6 with Comparative Examples 6 and 7, the alkali activity is as follows: potassium tert-butoxide ≈ sodium tert-butoxide > sodium methoxide > sodium ethoxide (yield decreases in that order). Molar ratios of alkali to 1-(1-chloroethyl)-4-(chloromethyl)benzene ranging from 1.05 to 1.7:1 are all effective, but the yield is low (84.2%) at 1.05:1, and while the yield is 89.5% at 1.7:1, the purity decreases slightly. Therefore, the optimal molar ratio is 1.1-1.55:1, with 1.11:1 in Example 1 being the best overall. Excessive alkali (Comparative Example 7, 2.0:1) or increased temperature (Comparative Example 6) both lead to a significant decrease in purity.

[0058] Comparing Examples 1, 9, and 10 with Comparative Example 9, it can be seen that the yield is 87.9% at 100W and 90.3% at 200W, but the purity drops to 94.8% at 300W. Therefore, the optimal power is 100~200W in the examples, with 150W being the optimal power in Example 1.

[0059] As can be seen from the comparison of Examples 1, 11, 12 and Comparative Example 10, if the solvent is too small (500 ml / mol), the yield will be only 79.0% and the purity will be 95.5%. Therefore, the optimal ratio is 800~1200 ml / mol as in the examples, of which 926 ml / mol (Example 1) has the best effect.

[0060] A comparison of Examples 1 and 13 shows that nitrogen and argon are equally effective and both can be used.

[0061] After comprehensive analysis, the optimal solution is represented by Example 1, which uses potassium tert-butoxide (base:substrate = 1.11:1), vigorously stirred at 1000 rpm at 10~15℃, intermittently sonicated (12s / 25s, 150W), with a solvent ratio of about 926 ml / mol, under nitrogen protection, to obtain p-chloromethylstyrene with a yield of 90.1% and a purity of 99.5%, and with almost no ortho-isomers.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a single-structure p-chloromethylstyrene, characterized in that, Includes the following steps: S1: Dissolve 1-(1-chloroethyl)-4-(chloromethyl)benzene in tert-butanol under inert gas protection, cool to 10~15 ℃, and then add alkali in batches under vigorous stirring, maintaining the temperature of the reaction system between 10~15 ℃; S2: After the alkali is added, the reaction is continued to be vigorously stirred at 10~15 ℃ for 1~4 h. During vigorous stirring, the mixture is sonicated for 7~15 s and then allowed to stand for 20~30 s. After the reaction is completed, p-chloromethylstyrene is obtained through post-treatment.

2. The method for preparing a single-structure p-chloromethylstyrene according to claim 1, characterized in that, The alkali is at least one of potassium tert-butoxide, sodium tert-butoxide, sodium methoxide, and sodium ethoxide.

3. The method for preparing a single-structure p-chloromethylstyrene according to claim 2, characterized in that, The alkali is at least one of potassium tert-butoxide and sodium tert-butoxide.

4. The method for preparing a single-structure p-chloromethylstyrene according to claim 1, characterized in that, The molar ratio of the base to 1-(1-chloroethyl)-4-(chloromethyl)benzene is 1.05~1.7:

1.

5. The method for preparing a single-structure p-chloromethylstyrene according to claim 1, characterized in that, The speed of the vigorous stirring is 700~1500 rpm.

6. The method for preparing a single-structure p-chloromethylstyrene according to claim 1, characterized in that, The power of the ultrasonic treatment is 100~200 W.

7. The method for preparing a single-structure p-chloromethylstyrene according to claim 1, characterized in that, The mass-to-volume ratio of 1-(1-chloroethyl)-4-(chloromethyl)benzene to tert-butanol is 1 mol: 800~1200 ml.

8. The method for preparing a single-structure p-chloromethylstyrene according to any one of claims 1 to 7, characterized in that, The post-processing includes the following steps: the reaction solution is poured into ice water, then extracted multiple times with n-hexane, the organic phases are combined and washed with deionized water, the washed organic phase is dried with anhydrous magnesium sulfate, filtered, the filtrate is distilled under reduced pressure by a water pump to recover n-hexane, and then the fraction at 70-80 °C is collected by distillation under reduced pressure by an oil pump to obtain the colorless and transparent liquid product p-chloromethylstyrene.

9. The method for preparing a single-structure p-chloromethylstyrene according to any one of claims 1 to 7, characterized in that, The inert gas is either nitrogen or argon.

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