Three-stage continuous production method of 4, 6-dinitro-o-sec-butylphenol

Abstract

The invention discloses a three-stage continuous production method of 4, 6-dinitro-o-sec-butylphenol, which is carried out in a static continuous tubular reactor, and the static continuous tubular reactor comprises a sulfonation unit, a sulfonation unit, a reaction unit and a reaction unit, the sulfonation unit comprises a first static reaction pipe, a first mixer connected with a feeding hole of the first static reaction pipe, a first feeding pump communicated with the first mixer through a first pipeline, and a second feeding pump communicated with the first mixer through a second pipeline; the first nitration unit comprises a second static reaction pipe, a second mixer and a third feeding pump; the second mixer is connected with a feeding hole of the second static reaction pipe and is communicated with a discharging hole of the first mixer through a third pipeline; the third feeding pump is communicated with the second mixer through a fourth pipeline; and a second nitration unit. The disproportionation reaction is less, the product selectivity is high, and the yield can reach 92% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of continuous production and relates to a production method of 4,6-dinitro-o-sec-butylphenol, and specifically relates to a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol. Background Art

[0002] 4,6-Dinitro-2-sec-butylphenol is mainly used as a high-temperature inhibitor for the distillation of vinyl aromatic compounds such as styrene and methyl styrene. It is also an intermediate for the manufacture of fine chemicals such as dyes, pesticides and fungicides. At present, the conventional production method of 4,6-Dinitro-2-sec-butylphenol (DNBP) is to use 2-sec-butylphenol and sulfuric acid as raw materials for sulfonation reaction to generate sulfonation liquid, add the sulfonation liquid to the prepared pure nitric acid aqueous solution for primary nitration to generate primary nitration liquid, and then add the prepared pure nitric acid aqueous solution to the primary nitration liquid for secondary nitration, and finally separate the waste liquid from the obtained nitration liquid, and wash and dehydrate it to obtain 4,6-Dinitro-2-sec-butylphenol. This method has a large one-time investment, high maintenance cost, and occupies a large area. In addition, since the existing acid solutions used for nitration are all pure nitric acid aqueous solutions, there are many disproportionation reactions (low conversion rate), resulting in a low yield of 4,6-dinitro-o-sec-butylphenol product (87-88%) and a large amount of heat release; since the heat exchange and heat transfer capacity of the jacket of the kettle reaction is low, the product quality is poor.

[0003] The Chinese invention patent with application number 200810151230.2 discloses a method for continuous production of 4,6-dinitro-o-sec-butylphenol polymerization inhibitor, which includes the following steps: connecting multiple reactors in series by using a potential difference, adding the reaction materials o-sec-butylphenol, sulfuric acid, and nitric acid in order and continuously by metering flow rate according to the molar ratio of sulfuric acid to o-sec-butylphenol of 1:1.2-1.4 and the molar ratio of nitric acid to o-sec-butylphenol of 1:2.2-3.2 to the reactor equipment, controlling the temperature by ice-salt water vapor, and obtaining the product by a continuous stratifier; the dilute sulfuric acid produced in the reaction is subjected to high vacuum distillation by an efficient enamel kettle to obtain 70-90% sulfuric acid for reuse, and the product yield is more than 92%. This application requires the use of ice-salt water vapor to control the temperature and the process is strict; and connecting multiple reactors in series by using a potential difference requires a large space in the height direction. Summary of the invention

[0004] The purpose of the present invention is to provide a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol in order to overcome the shortcomings of the prior art, so as to improve the yield and purity of 4,6-dinitro-o-sec-butylphenol.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol, which is carried out in a static continuous tubular reactor, wherein the static continuous tubular reactor comprises:

[0006] A sulfonation unit, the sulfonation unit comprising a first static reaction tube, a first mixer connected to a feed inlet of the first static reaction tube, a first feed pump connected to the first mixer via a first pipeline, and a second feed pump connected to the first mixer via a second pipeline;

[0007] A first nitration unit, the first nitration unit comprising a second static reaction tube, a second mixer connected to a feed inlet of the second static reaction tube and connected to a feed outlet of the first mixer through a third pipeline, and a third feed pump connected to the second mixer through a fourth pipeline;

[0008] The second nitration unit includes a third static reaction tube, a third mixer connected to the feed inlet of the third static reaction tube and connected to the discharge outlet of the second mixer through a fifth pipeline, and a fourth feed pump connected to the third mixer through a sixth pipeline.

[0009] Optimally, the following steps are included:

[0010] (a) using o-sec-butylphenol and sulfuric acid as raw materials to carry out a sulfonation reaction in the first static reaction tube to generate a sulfonated liquid; the molar ratio of the o-sec-butylphenol to the sulfuric acid is 1:1.2-1.4;

[0011] (b) using the sulfonated liquid and nitric acid as raw materials to carry out a nitration reaction in the second static reaction tube to generate a nitro product; the molar ratio of the o-sec-butylphenol to the nitric acid is 1:1 to 1.4;

[0012] (c) using the mononitrate product and nitric acid as raw materials to carry out a nitration reaction in the third static reaction tube to generate the 4,6-dinitro-o-sec-butylphenol; the molar ratio of the o-sec-butylphenol to the nitric acid is 1:1 to 1.4.

[0013] Furthermore, in step (a), the reaction temperature of the sulfonation reaction is 100-120° C. and the time is 0.5-1 h.

[0014] Furthermore, the mass concentration of the sulfuric acid is 90%-98%.

[0015] Furthermore, in step (b), the reaction temperature of the nitration reaction is 30-50° C. and the time is 1-3 min.

[0016] Furthermore, in step (b), the mass concentration of the nitric acid is 20%-30%.

[0017] Furthermore, in step (c), the reaction temperature of the nitration reaction is 80-100° C. and the time is 5-10 min.

[0018] Furthermore, in step (c), the mass concentration of the nitric acid is 60%-80%.

[0019] Optimally, the materials of the first static reaction tube, the second static reaction tube and the third static reaction tube are independently Hastelloy, PTFE or PFA, and the inner diameters thereof are 2 to 10 mm.

[0020] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol of the present invention adopts a tubular reactor capable of continuous production, so that the disproportionation reaction is less, the product selectivity is high, and the yield can reach 92% or more; the static tubular reactor has a high heat exchange effect, can quickly remove a large amount of heat generated by the reaction, and has a high temperature control ability; continuous and uninterrupted production, the production capacity value of a single device is large, and the comprehensive production capacity is effectively improved; the reaction equipment is small, the floor space is small, and a larger space can be allocated to other processes, and heat loss is reduced, and energy consumption is lower. The reactor replaces the dynamic equipment and is changed to a static equipment, with a small probability of damage, low maintenance cost, safer and neater production, and no noise pollution; it can greatly improve the degree of automation, reduce the input of operators, and reduce human factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the static continuous tubular reactor of the present invention. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention will be described in detail below.

[0023] Example 1

[0024] This embodiment provides a static continuous tubular reactor, such as Figure 1 As shown, it comprises a sulfonation unit 1, a first nitration unit 2 and a second nitration unit 3.

[0025] The sulfonation unit 1 includes a first static reaction tube 11, a first mixer 12, a first feed pump 13 and a second feed pump 14. The first mixer 12 is connected to the feed port of the first static reaction tube 11, and is used to mix the first feed (o-sec-butylphenol) and the second feed (concentrated sulfuric acid); the first mixer 12 can be manual, and more preferably automatic, which is conducive to improving the automation of the static continuous tubular reactor. The first feed pump 13 is connected to the first mixer 12 through a first pipeline, and is used to transport o-sec-butylphenol to the first mixer 12. The second feed pump is connected to the first mixer 12 through a second pipeline, and is used to transport concentrated sulfuric acid to the first mixer 12.

[0026] The first nitration unit 2 includes a second static reaction tube 21, a second mixer 22 and a third feed pump 23. The second mixer 22 is connected to the feed port of the second static reaction tube 21, and is connected to the discharge port of the first mixer 12 through a third pipeline, so as to mix the discharge of the first mixer 12 with the feed (nitric acid) of the third feed pump 23; the second mixer 22 can be manual, more preferably automatic, which is conducive to improving the automation degree of the static continuous tubular reactor. The third feed pump 23 is connected to the second mixer 22 through a fourth pipeline, so as to transport nitric acid to the second mixer 22.

[0027] The second nitration unit 3 includes a third static reaction tube 31, a third mixer 32 and a fourth feed pump 33. The third mixer 32 is connected to the feed port of the third static reaction tube 31, and is connected to the discharge port of the second mixer 22 through the fifth pipeline, so as to mix the discharge of the second mixer 22 with the feed (nitric acid) of the fourth feed pump 33; the third mixer 32 can be manual, more preferably automatic, which is conducive to improving the automation degree of the static continuous tubular reactor. The fourth feed pump 33 is connected to the third mixer 32 through the sixth pipeline, and is used to transport nitric acid to the third mixer 32; it should be noted that the concentration of nitric acid input by the fourth feed pump 33 is different from the concentration of nitric acid input by the aforementioned third feed pump 23.

[0028] In this embodiment, the materials of the first static reaction tube 11, the second static reaction tube 21 and the third static reaction tube 31 are independently Hastelloy, PTFE or PFA (or at least their inner walls are made of PTFE or PFA), and their inner diameters are independently 2 to 10 mm.

[0029] Example 2

[0030] The present embodiment provides a method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol, which uses the static continuous tubular reactor in Example 1 (the lengths of the first static reaction tube 11, the second static reaction tube 21 and the third static reaction tube 31 are 60m, 50m and 50m respectively, and the inner diameter is 5mm), and comprises the following steps:

[0031] (a) using o-sec-butylphenol and sulfuric acid as raw materials (the molar ratio of o-sec-butylphenol to sulfuric acid (concentration of 98%) is 1:1.4, the flow rate of o-sec-butylphenol is 3 g / min, and the molar ratio of sulfuric acid can be adjusted accordingly) to carry out a sulfonation reaction in a first static reaction tube 11 to generate a sulfonated liquid (the sulfonation reaction temperature is 100-120° C. and the time is 0.5-1 h. Within this range, the quality of the sulfonated liquid is not much different; the same below);

[0032] (b) using the above sulfonated liquid and nitric acid (the molar ratio of o-sec-butylphenol to nitric acid is 1:1.2, and the mass concentration of nitric acid is 30%) as raw materials to carry out a nitration reaction (reaction temperature is 30-50° C., time is 1-3 min) to generate a nitrate product;

[0033] (c) The mononitrate product and nitric acid (the molar ratio of o-sec-butylphenol to nitric acid is 1:1.2, and the mass concentration of nitric acid is 80%) are used as raw materials for nitration reaction to obtain output liquid; after the output liquid is allowed to stand for stratification in a separatory funnel, the lower organic phase (90.81 g) is taken; the organic phase is transferred into a three-necked flask containing 0.91 g of soda ash and 45.41 g of water for neutralization, and then allowed to stand for stratification and the organic phase is taken for further water washing, and finally the obtained organic phase is vacuum dried (temperature 80-100° C.) and dehydrated to obtain the product 4,6-dinitro o-sec-butylphenol. After testing, the purity of 4,6-dinitro o-sec-butylphenol is 98%, and the calculated yield is 92%.

[0034] Example 3

[0035] This embodiment provides a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that: in step (a), the molar ratio of o-sec-butylphenol to sulfuric acid (concentration of 98%) is 1:1.2;

[0036] In step (b), the molar ratio of o-sec-butylphenol to nitric acid (concentration of 30%) is 1:1;

[0037] In step (c), the molar ratio of o-sec-butylphenol to nitric acid (concentration of 80%) is 1:1.

[0038] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 94% and the calculated yield was 86%.

[0039] Example 4

[0040] This embodiment provides a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that: in step (a), the molar ratio of o-sec-butylphenol to sulfuric acid (concentration of 98%) is 1:1.3;

[0041] In step (b), the molar ratio of o-sec-butylphenol to nitric acid (concentration of 30%) is 1:1.1;

[0042] In step (c), the molar ratio of o-sec-butylphenol to nitric acid (concentration of 80%) is 1:1.1.

[0043] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 96% and the calculated yield was 90%.

[0044] Example 5

[0045] This embodiment provides a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that: in step (b), the concentration of nitric acid is 20%; in step (c), the concentration of nitric acid is 60%.

[0046] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 97% and the calculated yield was 90%.

[0047] Example 6

[0048] This embodiment provides a three-stage continuous production method of 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that: in step (b), the concentration of nitric acid is 25%; in step (c), the concentration of nitric acid is 70%.

[0049] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 98% and the calculated yield was 91%.

[0050] Comparative Example 1

[0051] This example provides a three-stage continuous production method for 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that the concentration of nitric acid in step (b) and step (c) is 50%.

[0052] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 40% and the calculated yield was 33%.

[0053] Comparative Example 2

[0054] This example provides a three-stage continuous production method for 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that: in step (b), the concentration of nitric acid is 10%; in step (c), the concentration of nitric acid is 90%.

[0055] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 72% and the calculated yield was 68%.

[0056] Comparative Example 3

[0057] This example provides a three-stage continuous production method for 4,6-dinitro-o-sec-butylphenol, which is basically the same as that in Example 2, except that in step (a), the concentration of sulfuric acid is 50%.

[0058] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 38% and the calculated yield was 31%.

[0059] Comparative Example 4

[0060] This example provides an intermittent reaction method of 4,6-dinitro-o-sec-butylphenol, which is as follows:

[0061] (1) Sulfonation reaction of o-sec-butylphenol

[0062] Add 66.7g of o-sec-butylphenol to the reaction kettle; start stirring, heat to 58°C, slowly drop 66.7g of sulfuric acid (93%); the sulfuric acid drop time is controlled to be about 3 hours; after the sulfuric acid is added dropwise, heat to 100°C and keep warm for 2 hours. After the insulation is completed, cool to 80°C, slowly drop 26.7g of water into the sulfonation kettle, continue to cool to 60-70°C, and stop stirring.

[0063] (2) Primary nitrification reaction

[0064] Put water into the kettle; start stirring, and put 140g of 28.7% nitric acid into the reactor. When the reaction temperature is 35-38°C, start to drop 180g of sulfonate (the product of the previous step), and control the drop temperature to ≤39°C. The drop time is controlled to be 7-8 hours. After the drop addition of the sulfonate is completed, keep the temperature at 38±2°C for 1.5 hours, stop stirring, and the material is ready for secondary nitration.

[0065] (3) Secondary nitrification reaction

[0066] Prepare 70% nitric acid. Add the mononitrosulfonate (the product of step (a)) to the secondary nitration kettle. Heat to about 50°C, wait for the temperature to slowly rise to about 58°C, start to drip 57.4g of 70% nitric acid, and control the dripping temperature at 62±2°C. The dripping time is controlled to be about 3 to 4 hours. After the 70% nitric acid is dripped, heat to 100±2°C and keep the reaction warm for 2 hours. The heating process is controlled to be about 3 to 4 hours. Let it stand for 30 minutes. After the materials are layered, take out the organic phase for neutralization and washing, and the aqueous phase goes to the waste liquid tank.

[0067] (4) Neutralization and water washing

[0068] Add the organic phase to a three-necked flask, add alkali solution (1g of soda ash in 45g of water) to neutralize and wash. Stand at 80℃ for 30 minutes. After the material is separated, take out the organic phase and wash it with water. Add 45g of clean water to the three-necked flask to wash the organic phase. Stand at 80℃ for 30 minutes. After the material is separated, take out the organic phase and dry it.

[0069] (5) Dehydration

[0070] Vacuum drying and dehydration, the temperature is controlled at 80-100℃. Cool down to about 50-60℃, weigh and measure the DNBP, and take samples for analysis.

[0071] After testing, the purity of 4,6-dinitro-o-sec-butylphenol was 92% and the calculated yield was 84%.

[0072] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol, characterized in that: It is carried out in a static continuous tubular reactor, which comprises: A sulfonation unit (1), the sulfonation unit (1) comprising a first static reaction tube (11), a first mixer (12) connected to a feed inlet of the first static reaction tube (11), a first feed pump (13) connected to the first mixer (12) via a first pipeline, and a second feed pump (14) connected to the first mixer (12) via a second pipeline; A first nitration unit (2), the first nitration unit (2) comprising a second static reaction tube (21), a second mixer (22) connected to a feed inlet of the second static reaction tube (21) and connected to a feed outlet of the first mixer (12) via a third pipeline, and a third feed pump (23) connected to the second mixer (22) via a fourth pipeline; A second nitration unit (3), the second nitration unit (3) comprising a third static reaction tube (31), a third mixer (32) connected to the feed inlet of the third static reaction tube (31) and connected to the feed outlet of the second mixer (22) via a fifth pipeline, and a fourth feed pump (33) connected to the third mixer (32) via a sixth pipeline.

2. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 1, characterized in that: The following steps are involved: (a) using o-sec-butylphenol and sulfuric acid as raw materials to carry out a sulfonation reaction in the first static reaction tube (11) to generate a sulfonated liquid; the molar ratio of the o-sec-butylphenol to the sulfuric acid is 1:1.2-1.4; (b) using the sulfonated liquid and nitric acid as raw materials to carry out a nitration reaction in the second static reaction tube (21) to generate a nitro product; the molar ratio of the o-sec-butylphenol to the nitric acid is 1:1-1.4; (c) using the mononitrate product and nitric acid as raw materials to carry out a nitration reaction in the third static reaction tube (31) to generate the 4,6-dinitro-o-sec-butylphenol; the molar ratio of the o-sec-butylphenol to the nitric acid is 1:1-1.

4.

3. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 2, characterized in that: In step (a), the reaction temperature of the sulfonation reaction is 100-120° C. and the time is 0.5-1 h.

4. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 3, characterized in that: The mass concentration of the sulfuric acid is 90%-98%.

5. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 2, characterized in that: In step (b), the reaction temperature of the nitration reaction is 30-50° C. and the reaction time is 1-3 min.

6. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 5, characterized in that: In step (b), the mass concentration of the nitric acid is 20%-30%.

7. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 2, characterized in that: In step (c), the reaction temperature of the nitration reaction is 80-100° C. and the time is 5-10 min.

8. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 7, characterized in that: In step (c), the mass concentration of the nitric acid is 60%-80%.

9. The method for three-stage continuous production of 4,6-dinitro-o-sec-butylphenol according to claim 1, characterized in that: The materials of the first static reaction tube (11), the second static reaction tube (21) and the third static reaction tube (31) are independently Hastelloy, PTFE or PFA, and their inner diameters are 2 to 10 mm.

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