Preparation method of chlorinated paraffin 70 with high softening point

Abstract

The invention provides a preparation method of chlorinated paraffin 70 with a high softening point, and belongs to the technical field of chlorinated paraffins.The preparation method comprises the steps that S1, mixed wax is provided, and raw materials of the mixed wax are Fischer-Tropsch wax and petrochemical wax; s2, feeding the mixed wax into a reactor, then turning on an ultraviolet lamp in the reactor for irradiation, after liquid chlorine is gasified to form chlorine, feeding chlorine into the reactor, heating and carrying out segmented control reaction; s3, after the reaction is finished, blowing air into the reactor, then washing a reaction product with water, and then adding a compound stabilizer into a crude product obtained by washing with water, so as to obtain chlorinated paraffin 70; the chlorine content of the chlorinated paraffin 70 is not less than 69.5%, the softening point is not less than 98 DEG C, and the acid value is not more than 0.1 mgKOH / g. According to the method, hot chlorination and photo-initiation are combined, so that the chlorine content and the softening point of the product are controllable, the production efficiency is high, the reaction speed is high, the reaction temperature is reduced, the production period is shortened, and the product quality is stable.

Description

Technical Field

[0001] This invention relates to the field of chlorinated paraffin technology, and more particularly to a method for preparing chlorinated paraffin 70 with a high softening point. Background Technology

[0002] Chlorinated paraffin 70 (RCl-70), also known as chlorinated paraffin 70, is an additive flame retardant with the chemical formula C. 25 H 30 Cl 22 The CAS number is 106232-86-4. It has a chlorine content of 68-72%, is a white powder, odorless, insoluble in water and lower alcohols, but soluble in mineral oil, aromatics, chloroalkanes, ether, acetone, esters, and other organic solvents. This substance exhibits flame retardant durability, good chemical stability, and also possesses moisture-proof, antistatic, and compression-resistant properties. It is mainly used as an additive flame retardant in the production and processing of polyvinyl chloride, polyethylene, and other resins and rubber products (such as conveyor belts and materials), and is also applied in fire-retardant coatings, wood preservation and insect prevention, and paper sizing processes. In existing technologies, it has been found that achieving both high chlorine content and a high softening point simultaneously is difficult, resulting in a generally low softening point for the product (chlorine content is typically 68-69.5%, softening point is generally 90-95℃), limiting its application in high-temperature environments, such as its tendency to soften, volatilize, and migrate. If traditional limitations can be overcome through process optimization or molecular structure design to increase its softening point (e.g., >95℃), its heat resistance, stability, and operating temperature range can be improved, enabling it to maintain structural stability at high temperatures. This makes it suitable for fields requiring high-temperature processing (such as cable sheaths, engineering plastics, high-temperature coatings, and sealants for new energy battery packs), achieving product differentiation and high-end positioning, and providing a broad market space for chlorinated paraffin 70.

[0003] There are three main methods for preparing chlorinated paraffin 70 in China: One is the "carbon tetrachloride solvent method," which is a relatively mature process. The reaction occurs at room temperature and pressure, is relatively fast, and easily meets the technical requirements for chlorine content and softening point. However, it requires a large amount of carbon tetrachloride as a solvent. Because carbon tetrachloride has a low boiling point, is highly volatile, and is highly toxic to humans, it is also an ozone-depleting substance and is banned worldwide. This method is now largely prohibited. Furthermore, this method is very complex, with excessively high equipment investment, high production costs, severe equipment corrosion, and harsh working conditions for workers. Another method is the "aqueous phase method," which has a fast reaction rate and a softening point reaching 100℃. However, it requires higher investment and has more stringent chlorination conditions. Additionally, the hot dilute acid generated during chlorination is difficult to recover and corrodes chlorination and separation equipment, thus placing high demands on key equipment such as chlorination reactors and separators. Moreover, the semi-finished product after washing with dilute acid is difficult to dry. Another method is thermal chlorination, which aims to produce RCl-70 by increasing the reaction temperature, activation energy, and reducing material viscosity. However, products obtained through this method generally suffer from poor color, low softening point, easy decomposition, and instability. Furthermore, the chlorination process is slow, making it quite difficult to achieve the specified chlorine content. Additionally, the product exhibits poor thermal stability and limited performance, restricting its application. Therefore, the commonly used methods for preparing chlorinated paraffin 70 all have their own drawbacks, making the preparation of chlorinated paraffin 70 with a high softening point quite challenging. Summary of the Invention

[0004] This invention provides a method for preparing high-softening-point chlorinated paraffin 70, which features controllable chlorine content and softening point, high production efficiency, fast reaction speed, reduced reaction temperature, shortened production cycle, and stable product quality, thereby solving the aforementioned problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides a method for preparing chlorinated paraffin 70 with a high softening point, comprising: S1: Provides blended waxes, the raw materials of which are Fischer-Tropsch wax and petrochemical wax; S2: The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised and the reaction is carried out in stages. S3: After the reaction is complete, air is blown into the reactor, and then the reaction product is washed with water. Then, a composite stabilizer is added to the crude product obtained by water washing to obtain chlorinated paraffin 70. The chlorine content of the above chlorinated paraffin 70 is not less than 69.5%, the softening point is ≥98℃, and the acid value is ≤0.1mgKOH / g.

[0006] The preparation method of this invention combines thermal chlorination and photoinitiation, which accelerates the reaction rate, reduces the reaction temperature, shortens the production cycle, and saves production costs. By introducing high-melting-point coal-based Fischer-Tropsch wax into the raw materials and optimizing the ratio of coal-based Fischer-Tropsch wax to refined petrochemical wax, and by using gradient-limited chlorination flow rate combined with staged chlorination and temperature and pressure gradient control, the balance point between the chlorination depth and molecular structure of the reaction product is found. This makes the chlorine content and softening point of the product controllable, combining high chlorine content and high softening point, ensuring the chemical stability, temperature resistance, and performance of the product. It also features simple preparation process, high production efficiency, fast reaction speed, thorough reaction, stable product quality, and safety, environmental protection, and no pollution.

[0007] The setting is further configured such that the mass ratio of Fischer-Tropsch wax to petrochemical wax is 1:(0.6-3). The mass ratio of Fischer-Tropsch wax to petrochemical wax mentioned above includes, but is not limited to, 1:3, 1:1.5, 1:1, 1:0.7, etc.

[0008] Further configured, the Fischer-Tropsch wax is a coal-based Fischer-Tropsch wax with a straight-chain alkane content of not less than 95% and a carbon chain length of C20-C30; the petrochemical wax is a refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C18-C30. Preferably, the carbon chain length of the refined petrochemical wax is C20-25. More preferably, the Fischer-Tropsch wax and the petrochemical wax are mixed in a molten state to obtain a liquid mixed wax.

[0009] High-melting-point coal-based Fischer-Tropsch wax is introduced into the raw materials. Coal-based Fischer-Tropsch wax and refined petrochemical wax are selected as raw materials and mixed together. The ratio of raw materials is optimized to produce chlorinated paraffin 70 that meets the requirements of high softening point, thereby significantly improving the product performance. In particular, both Fischer-Tropsch wax and petrochemical wax are selected from raw materials with high content of straight-chain alkanes and long carbon chain length. Their molecular structure is regular, and after chlorination, there are fewer branches, stronger molecular weight and intermolecular forces, and higher softening point, thereby enhancing the softening point and stability of the product.

[0010] The mixture is further configured with a mass ratio of mixed wax to chlorine of 1:(4.5-5). When chlorine is introduced into the mixed wax, it decomposes into active chlorine atoms under ultraviolet irradiation and thermal conditions. Through the combined action of thermal chlorination and photoinitiation, these active chlorine atoms replace hydrogen in the paraffin wax, generating hydrogen chloride and alkyl free radicals. The free radical-containing alkanes and chlorine molecules further react to generate new active chlorine atoms and chloroalkanes. These active chlorine atoms and chloroalkanes then react again to generate free radical-containing chloroalkanes and hydrogen chloride. This is a chain reaction, and the reaction terminates when the free radicals disappear, forming stable molecules. Combining thermal chlorination and photoinitiation allows for rapid initiation of the chlorine free radical substitution reaction, releasing a large amount of heat. This enables the chlorination reaction to begin and complete quickly, shortening the production cycle and saving production costs. The reaction endpoint can be determined by measuring the chlorine content of the product. When the chlorine content reaches 69.5% or higher, the target product has been obtained, and the reaction can be stopped. Timely termination of the reaction also avoids excessively high molecular weight products that could affect processability.

[0011] The reaction is further configured as follows: In the initial stage, the reaction temperature is controlled at 80-100℃, the reaction time at 19-20 hours, and the reaction pressure at atmospheric pressure; in the middle stage, the reaction temperature is controlled at 100-110℃, the reaction time at 1-2 hours, and the reaction pressure at 0.1-0.2 MPa; in the later stage, the reaction temperature is controlled at 105-125℃, the reaction time at 4-6 hours, and the reaction pressure at 0.25-0.35 MPa. The chlorination reaction employs staged chlorination and temperature and pressure gradient control. The lower temperature and pressure in the initial stage primarily promote the initial reaction and increase the softening point, avoiding localized overheating and controlling thermal degradation and free radical polymerization during chlorination. The gradually increasing reaction temperature and pressure in the middle and later stages are intended to reduce degradation and branching content, preventing excessively low molecular weight products that would lower the softening point, further improving the softening point and stability of the product, thereby enhancing product quality and overall performance stability.

[0012] The chlorine flow rate during the reaction is further set to 60-100 m³ / h. 3 The chlorine flow rate was controlled in stages, with the initial flow rate > intermediate flow rate > later flow rate. Chlorine was continuously introduced into the reactor throughout the reaction. The initial flow rate was slightly higher because the amount of chlorinated paraffin was small and its viscosity was low, which facilitated chlorine diffusion and reaction. The flow rate decreased in the intermediate and later stages to prevent incomplete chlorine reaction, waste, and side reactions. By controlling the chlorination reaction conditions and utilizing a gradient-limited chlorine flow rate combined with staged reaction control, optimal reaction conditions for high chlorine content (e.g., above 70%) and high softening point were determined. This reduced degradation, decreased branched content in the products, improved molecular regularity, and found a balance between the chlorination depth (high chlorine content) and molecular structure (reduced degradation, maintained high softening point) of the reaction products.

[0013] Further, the reaction is controlled in stages, with ultraviolet (UV) irradiation throughout, using a wavelength of 350-400 nm. The UV lamps are placed in the reactor, with a structure consistent with existing technologies, without specific limitations, as long as uniform irradiation and heating are ensured. Irradiation with specific wavelength UV lamps facilitates the conversion of chlorine gas into active chlorine atoms, resulting in high initiation efficiency, accelerated reaction rate, shortened reaction time, lower reaction temperature, and reduced energy costs. Combining thermal chlorination with photoinitiation, compared to traditional thermal chlorination, lowers the reaction temperature, reduces the corrosive effect of the medium on equipment, lowers the material requirements for equipment pipelines, and reduces the formation of by-products through low-temperature reaction. The softening point of the product is also increased, avoiding the darkening of color caused by material decomposition at high temperatures, thereby improving product quality.

[0014] Further, the amount of composite stabilizer added is 0.1-0.3% of the weight of the crude product.

[0015] The composite stabilizer is further configured as ethylene glycol diglycidyl ether and 2-hydroxy-4-methoxybenzophenone in a weight ratio of 1:1. After the reaction is complete, the tail gas from the reactor is sent to a tail gas treatment system via dry air to recover hydrogen chloride and chlorine. Then, it is washed with water to achieve deacidification and decolorization, preventing residual impurities from affecting product stability. Finally, a polymerization inhibitor or stabilizer is introduced to suppress side reactions and further improve the product's stability and flame retardancy.

[0016] The present invention provides a method for preparing high-softening-point chlorinated paraffin 70. First, high-melting-point coal-based Fischer-Tropsch wax is introduced into the raw materials. The coal-based Fischer-Tropsch wax is mixed with refined petrochemical wax, and the optimal raw material ratio is optimized to produce chlorinated paraffin 70 that meets the high softening-point requirement. After chlorination, it has fewer branches, stronger molecular weight and intermolecular forces, and a higher softening point. Second, during the chlorination reaction, thermal chlorination and photoinitiation are combined to accelerate the reaction rate, shorten the reaction time, lower the reaction temperature, and save energy costs. The low-temperature reaction also reduces the formation of by-products. Furthermore, by utilizing gradient-limited chlorination flow rate combined with staged chlorination and temperature and pressure gradient control, a balance point between the chlorination depth and molecular structure of the reaction product is found. This allows for controllable chlorine content and softening point, reducing degradation and branching content, avoiding excessively low molecular weight leading to a lower softening point, and preventing excessively high molecular weight from affecting processability. This comprehensively improves the softening point and overall performance stability of the product. Finally, the product is purified by air blowing and water washing, and a composite stabilizer is added to improve the product's stability and flame retardancy. This results in a product with good stability, maintaining a more stable state during processing. It can be widely used in the production of cable materials, flooring materials, hoses, artificial leather, rubber products, and as an additive in coatings, lubricants, and other fields. Furthermore, it is not prone to clumping due to high temperatures during transportation, thus improving product quality and transportation reliability. It has broad prospects for promotion and significant social and economic benefits. Detailed Implementation

[0017] 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. Obviously, the described embodiments are only some embodiments of the present invention, and 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 also within the scope of protection of the present invention.

[0018] The following examples use conventional instruments and equipment in the art. Unless otherwise specified, the experimental materials and reagents used in the following examples are commercially available and conform to conventional specifications in the art. Any techniques or conditions not specifically described in the following examples can be performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0019] It should be noted that, in this invention and the following embodiments, unless otherwise specified, concentration, ratio, etc. are all weight concentration, weight ratio, etc., "%" all represent weight percentage, and "parts" all represent weight parts. These are common writing habits used by those skilled in the art, and therefore will not be repeated in this invention.

[0020] As a preferred embodiment, the present invention provides a method for preparing chlorinated paraffin 70 with a high softening point, specifically including the following steps: S1: Mix Fischer-Tropsch wax and petrochemical wax in a certain proportion to obtain a mixed wax.

[0021] S2: The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised, and the reaction is carried out in stages.

[0022] S3: After the reaction is complete, dry air is introduced into the reactor to purge and exhaust the tail gas. Then, the reaction product is washed with water, and a composite stabilizer is added to the crude product obtained by water washing. After stirring evenly and cooling, chlorinated paraffin 70 is obtained.

[0023] As an improvement to the aforementioned implementation, during the segmented control of the reaction, ultrasonic-assisted chlorination is used throughout the process. The specific operation is as follows: the ultrasonic oscillator is turned on, supplying the material in the reactor with a frequency of 165-230 kHz and a power of 3.0-3.6 W / cm². 2 Ultrasonic waves are used to oscillate the materials in the reactor, creating a cavitation effect that accelerates the breaking of CH bonds and the substitution reaction rate of active chlorine atoms. This makes the reaction more complete, increases the conversion rate of chlorine gas, and thus improves chlorination efficiency and the controllability of product structure. Under high chlorine content, it further enhances the softening point and heat resistance of the product.

[0024] The present invention will be further described in detail below with reference to embodiments. However, it should be understood that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Example 1

[0025] A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) In the molten state, Fischer-Tropsch wax and petrochemical wax are mixed at a mass ratio of 1:0.7 to obtain a mixed wax. The Fischer-Tropsch wax is a coal-based Fischer-Tropsch wax with a straight-chain alkane content of not less than 95% and a carbon chain length of C20-C30; the petrochemical wax is a refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C18-C30.

[0026] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised, and the reaction is carried out in stages under controlled conditions. The mass ratio of mixed wax to chlorine gas is 1:4.5.

[0027] The specific operation of the staged reaction control is as follows: In the initial stage, the reaction temperature is controlled at 80℃, the reaction time at 20 hours, and the reaction pressure at atmospheric pressure; in the middle stage, the reaction temperature is controlled at 100℃, the reaction time at 2 hours, and the reaction pressure at 0.2 MPa; in the later stage, the reaction temperature is controlled at 105℃, the reaction time at 6 hours, and the reaction pressure at 0.25 MPa. The chlorine flow rate during the reaction is 100 m³ / h. 3 / h, and the chlorine flow rate during the staged reaction is controlled in the order of early stage > middle stage > late stage.

[0028] 3) After the reaction is complete, dry air is introduced into the reactor to purge and exhaust the tail gas. Then, the reaction product is washed with water, and 0.1% by weight of the composite stabilizer is added to the crude product obtained by water washing. The mixture is stirred evenly and cooled to obtain chlorinated paraffin 70. The composite stabilizer is ethylene glycol diglycidyl ether and 2-hydroxy-4-methoxybenzophenone in a weight ratio of 1:1. Example 2

[0029] A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) In the molten state, Fischer-Tropsch wax and petrochemical wax are mixed in a mass ratio of 1:3 to obtain a mixed wax. The Fischer-Tropsch wax is a coal-based Fischer-Tropsch wax with a straight-chain alkane content of not less than 95% and a carbon chain length of C20-C30; the petrochemical wax is a refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C20-25.

[0030] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised, and the reaction is carried out in stages under controlled conditions. The mass ratio of mixed wax to chlorine gas is 1:5.

[0031] The specific operation of the staged reaction control is as follows: In the initial stage, the reaction temperature is controlled at 100℃, the reaction time is 19 hours, and the reaction pressure is atmospheric pressure; in the middle stage, the reaction temperature is controlled at 110℃, the reaction time is 1 hour, and the reaction pressure is 0.15 MPa; in the later stage, the reaction temperature is controlled at 125℃, the reaction time is 4 hours, and the reaction pressure is 0.35 MPa. The chlorine flow rate during the reaction is 70 m³ / h. 3 / h, and the chlorine flow rate during the staged reaction is controlled in the order of early stage > middle stage > late stage.

[0032] 3) After the reaction is complete, dry air is introduced into the reactor to purge and exhaust the tail gas. Then, the reaction product is washed with water, and 0.3% by weight of the composite stabilizer is added to the crude product obtained by water washing. The mixture is stirred evenly and cooled to obtain chlorinated paraffin 70. The composite stabilizer is ethylene glycol diglycidyl ether and 2-hydroxy-4-methoxybenzophenone in a weight ratio of 1:1. Example 3

[0033] A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) In the molten state, Fischer-Tropsch wax and petrochemical wax are mixed in a mass ratio of 1:1 to obtain a mixed wax. The Fischer-Tropsch wax is a coal-based Fischer-Tropsch wax with a straight-chain alkane content of not less than 95% and a carbon chain length of C20-C30; the petrochemical wax is a refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C20-25.

[0034] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised, and the reaction is carried out in stages under controlled conditions. The mass ratio of mixed wax to chlorine gas is 1:4.5.

[0035] The specific operation of the staged reaction control is as follows: In the initial stage, the reaction temperature is controlled at 90℃, the reaction time at 20 hours, and the reaction pressure at atmospheric pressure; in the middle stage, the reaction temperature is controlled at 105℃, the reaction time at 2 hours, and the reaction pressure at 0.2 MPa; in the later stage, the reaction temperature is controlled at 120℃, the reaction time at 5 hours, and the reaction pressure at 0.3 MPa. The chlorine flow rate during the reaction is 90 m³ / h. 3 / h, and the chlorine flow rate during the staged reaction is controlled in the order of early stage > middle stage > late stage.

[0036] 3) After the reaction is complete, dry air is introduced into the reactor to purge and exhaust the tail gas. Then, the reaction product is washed with water, and 0.2% by weight of the composite stabilizer is added to the crude product obtained by water washing. The mixture is stirred evenly and cooled to obtain chlorinated paraffin 70. The composite stabilizer is ethylene glycol diglycidyl ether and 2-hydroxy-4-methoxybenzophenone in a weight ratio of 1:1. Example 4

[0037] A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Consistent with step 1) in Example 3.

[0038] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. At the same time, the ultrasonic oscillator is turned on to supply the material in the reactor with a frequency of 200KHz and a power of 3.5w / cm. 2 The liquid chlorine is vaporized using ultrasound to form chlorine gas, which is then fed into the reactor, heated, and subjected to a staged controlled reaction. The mass ratio of the mixed wax to chlorine gas is 1:4.5.

[0039] The specific operation of the staged reaction control is as follows: In the initial stage, the reaction temperature is controlled at 90℃, the reaction time at 20 hours, and the reaction pressure at atmospheric pressure; in the middle stage, the reaction temperature is controlled at 105℃, the reaction time at 2 hours, and the reaction pressure at 0.2 MPa; in the later stage, the reaction temperature is controlled at 120℃, the reaction time at 5 hours, and the reaction pressure at 0.3 MPa. The chlorine flow rate during the reaction is 90 m³ / h. 3 / h, and the chlorine flow rate during the staged reaction is controlled in the order of early stage > middle stage > late stage.

[0040] 3) Consistent with step 3) in Example 3.

[0041] Comparative Example 1: A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C20-25 is heated to a molten state to obtain liquid raw material wax. That is, the wax source is entirely refined petrochemical wax, and coal-based Fischer-Tropsch wax is not used.

[0042] 2) Same as step 2) in Example 3, except that the liquid raw material wax in step 1) is replaced with mixed wax and fed into the reactor.

[0043] 3) Consistent with step 3) in Example 3.

[0044] Comparative Example 2: A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Consistent with step 1) in Example 3.

[0045] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, and the reaction is carried out for 27 hours at a reaction temperature of 90℃ and a reaction pressure of atmospheric pressure. The mass ratio of mixed wax to chlorine gas is 1:4.5. The chlorine flow rate control during the reaction is the same as in step 2) of Example 3.

[0046] 3) Consistent with step 3) in Example 3.

[0047] Comparative Example 3: A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Consistent with step 1) in Example 3.

[0048] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, and the reaction is carried out at a reaction temperature of 120℃ and a reaction pressure of 0.3MPa for 27 hours. The mass ratio of mixed wax to chlorine gas is 1:4.5. The chlorine flow rate control during the reaction is the same as in step 2) of Example 3.

[0049] 3) Consistent with step 3) in Example 3.

[0050] Comparative Example 4: A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Consistent with step 1) in Example 3.

[0051] 2) The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised, and the reaction is carried out in stages under controlled conditions. The mass ratio of mixed wax to chlorine gas is 1:4.5.

[0052] The specific operation of the staged reaction control is as follows: In the initial stage, the reaction temperature is controlled at 90℃, the reaction time at 20 hours, and the reaction pressure at atmospheric pressure; in the middle stage, the reaction temperature is controlled at 105℃, the reaction time at 2 hours, and the reaction pressure at 0.2 MPa; in the later stage, the reaction temperature is controlled at 120℃, the reaction time at 5 hours, and the reaction pressure at 0.3 MPa. The chlorine flow rate is kept constant at 90 m³ / s during the initial, middle, and later stages of the reaction. 3 / h.

[0053] 3) Consistent with step 3) in Example 3.

[0054] Comparative Example 5: A method for preparing chlorinated paraffin 70 with a high softening point includes the following steps: 1) Refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C20-25 is heated to a molten state to obtain liquid raw material wax. That is, the wax source is entirely refined petrochemical wax, and coal-based Fischer-Tropsch wax is not used.

[0055] 2) Liquid raw material wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. The ultraviolet wavelength is 350-400nm. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, and the reaction is carried out at a reaction temperature of 110℃ and a reaction pressure of 0.2MPa for 27 hours. The mass ratio of mixed wax to chlorine gas is 1:4.5. The chlorine flow rate is kept constant at 90m³ during the reaction. 3 / h.

[0056] 3) Consistent with step 3) in Example 3.

[0057] The chlorinated paraffin 70 products prepared in each example and comparative example were tested using the method in industry standard HG / T3643-1999. Each test sample group had 3 replicates, and the average value was taken. The results are shown in Table 1.

[0058] Table 1

[0059] As shown in the table above, the chlorinated paraffin 70 products prepared in each embodiment have a chlorine content of no less than 69.5%, a softening point ≥98℃, an acid value ≤0.1mgKOH / g, and a thermal stability index of less than 0.15%. The preparation method in Example 4 was optimized to achieve a chlorine content of over 72% and a softening point of over 110℃. The test data of each embodiment meet or even exceed the standards for superior products specified in the standard. In Comparative Example 5, the product prepared using only refined petrochemical wax as raw material and employing existing technology for the chlorination reaction only meets the standards for qualified products, limiting the application range of the product. The data from Comparative Examples 1-4 were all worse than those from the Example, with only some indicators meeting the superior product standard. This indicates that the preparation method in this invention achieves its optimal results by comprehensively considering the following conditions: ① Introducing high-melting-point coal-based Fischer-Tropsch wax into the raw materials, selecting coal-based Fischer-Tropsch wax and refined petrochemical wax as mixed raw materials, and optimizing the ratio to the best; ② Combining thermal chlorination and photoinitiation during the chlorination reaction; ③ Utilizing gradient-limited chlorine flow rate in conjunction with segmented chlorination and temperature and pressure gradient control to find the balance between the chlorination depth and molecular structure of the reaction product. This allows the chlorine content and softening point of the product to be controllable, possessing both high chlorine content and a high softening point, thus ensuring the product's chemical stability, temperature resistance, and performance.

[0060] It should be noted that some detailed steps of the operation are not described in this invention, but are prior art known to those skilled in the art, and therefore will not be repeated here. Furthermore, in this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0061] It should be noted that the detailed structure of some devices is not described in this invention, but is prior art known to those skilled in the art, and therefore will not be elaborated here. In this invention, structures and devices not specifically limited can be purchased commercially, and those skilled in the art only need to install and operate them according to the accompanying instruction manual, without requiring any creative effort from those skilled in the art.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. In this invention, not all possible combinations of the various technical features in each embodiment or implementation are described. As long as the combinations of these technical features do not contradict each other, the various technical features in each embodiment or implementation can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification. 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing chlorinated paraffin 70 with a high softening point, characterized in that, include: S1: Provide a mixed wax, the raw materials of which are Fischer-Tropsch wax and petrochemical wax; S2: The mixed wax is fed into the reactor, and then the ultraviolet lamp in the reactor is turned on for irradiation. After the liquid chlorine is vaporized to form chlorine gas, the chlorine gas is fed into the reactor, the temperature is raised and the reaction is carried out in stages. S3: After the reaction is complete, air is blown into the reactor, and then the reaction product is washed with water. A composite stabilizer is then added to the crude product obtained from the water washing to obtain chlorinated paraffin 70. The chlorinated paraffin 70 has a chlorine content of not less than 69.5%, a softening point of ≥98℃, and an acid value of ≤0.1mgKOH / g.

2. The method for preparing high softening point chlorinated paraffin 70 according to claim 1, characterized in that, The mass ratio of the Fischer-Tropsch wax to the petrochemical wax is 1:(0.6-3).

3. The method for preparing high softening point chlorinated paraffin 70 according to claim 1 or 2, characterized in that, The Fischer-Tropsch wax is a coal-based Fischer-Tropsch wax with a straight-chain alkane content of not less than 95% and a carbon chain length of C20-C30; the petrochemical wax is a refined petrochemical wax with a straight-chain alkane content of not less than 90% and a carbon chain length of C18-C30.

4. The method for preparing high softening point chlorinated paraffin 70 according to claim 1, characterized in that, The mass ratio of the mixed wax to chlorine is 1:(4.5-5).

5. The method for preparing high softening point chlorinated paraffin 70 according to claim 1, characterized in that, The specific operation of the segmented controlled reaction is as follows: In the early stage, the reaction temperature is controlled at 80-100℃, the reaction time is 19-20h, and the reaction pressure is atmospheric pressure; in the middle stage, the reaction temperature is controlled at 100-110℃, the reaction time is 1-2h, and the reaction pressure is 0.1-0.2MPa; in the later stage, the reaction temperature is controlled at 105-125℃, the reaction time is 4-6h, and the reaction pressure is 0.25-0.35MPa.

6. The method for preparing high softening point chlorinated paraffin 70 according to claim 1 or 5, characterized in that, The chlorine flow rate during the reaction is 60-100 m³ / h. 3 / h, and the chlorine flow rate during the staged reaction is controlled in the order of early stage > middle stage > late stage.

7. The method for preparing high softening point chlorinated paraffin 70 according to claim 1 or 5, characterized in that, During the segmented controlled reaction, ultraviolet irradiation is used throughout the process, with an ultraviolet wavelength of 350-400nm.

8. The method for preparing high softening point chlorinated paraffin 70 according to claim 1, characterized in that, The amount of the composite stabilizer added is 0.1-0.3% of the weight of the crude product.

9. The method for preparing high softening point chlorinated paraffin 70 according to claim 1 or 8, characterized in that, The composite stabilizer is ethylene glycol diglycidyl ether and 2-hydroxy-4-methoxybenzophenone in a weight ratio of 1:1.

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