Reaction process for utilizing dynamic tubular reactor at 2-naphtholic acid working section

Abstract

The invention belongs to the field of organic chemical industry, and provides a reaction process for a 2-naphthol acidification section by using a dynamic tubular reactor. Compared with the prior art, the process is mainly characterized in that the process comprises the following steps: respectively storing the alkali fusion material and SO2, simultaneously feeding the alkali fusion material and SO2 into a reactor according to a ratio for reaction, and simultaneously carrying out continuous flow reaction by controlling the feeding flow and the reaction temperature and using a tubular reactor, wherein the reactor uses a circulating pump to carry out forced reaction to finally obtain a qualified product. The process provided by the invention is high in operation continuity, automation and safety coefficient in production of 2-naphthol, the obtained product is high in stability, the mixing efficiency and the thermal conversion efficiency are both improved, and more prominently, the reaction time can be accurately controlled.

Description

Technical Field

[0001] The invention belongs to the field of organic chemical industry, and specifically relates to a 2-naphthol acid chemical process using a dynamic tubular reactor. Background Art

[0002] 2-Naphthol is an important organic raw material and dye intermediate. It is used to manufacture tobiased acid, butyric acid, β-naphthol-3-carboxylic acid, antioxidant DNP and other antioxidants, organic pigments and fungicides. It can also be used as a reagent for the determination of sulfonamides and aromatic amines by thin layer chromatography. It is also used in organic synthesis. It is used to improve cathode polarization, refine crystals and reduce pores in acid tin plating. Because this product is hydrophobic, too high a content will cause gelatin to coagulate and precipitate, and stripes will appear on the coating. It is mainly used in the production of acid orange Z, acid orange II, acid black ATT, acid mordant black T, acid mordant black A, acid mordant black R, acid complex pink B, acid complex red brown BRRW, acid complex black WAN, chromophore AS, chromophore AS-D, chromophore AS-OL, chromophore AS-SW, reactive brilliant orange X-GN, reactive brilliant orange K-GN, reactive red K-1613, neutral violet BL, neutral black BGL, direct cuprate blue 2R, direct fast blue B2PL, direct blue RG, direct blue RW and other dyes.

[0003] 2-Naphthol is prepared from naphthalene by sulfonation and alkali fusion. The sulfonation alkali fusion method is a production method widely used at home and abroad. For example, patent CN105347578A discloses an improved 2-naphthol synthesis process, wherein refined naphthalene is subjected to sulfonation, hydrolysis, neutralization, alkali fusion, acidification, refining and other steps to obtain 2-naphthol products and wastewater, and finally the wastewater is treated: characterized in that the wastewater treatment method comprises the following steps: (1) pretreatment: 2-naphthol wastewater is subjected to pretreatment to remove organic impurities in the wastewater to obtain a salt-containing filtrate; (2) bipolar membrane desalination: the pretreated filtrate is subjected to bipolar membrane electrodialysis treatment to obtain sulfuric acid, sodium hydroxide solution and dilute brine, the dilute brine is concentrated by electrodialysis, and the concentrated brine is subjected to bipolar membrane electrodialysis treatment; (3) acid and alkali reuse: the obtained sulfuric acid and sodium hydroxide solution are reused in the 2-naphthol synthesis process and / or step (1) to achieve process in-process application. This invention not only achieves the discharge of 2-naphthol wastewater in compliance with the standards, but also recovers the effective resources in the wastewater by introducing bipolar membrane technology, thus reducing the production cost of 2-naphthol. However, it has severe corrosion, high cost, and high biological oxygen consumption in the wastewater.

[0004] Another example is CN104016835A, which relates to an optimized production process for sulfonation and alkali fusion of 2-naphthol. The invention uses refined naphthalene as raw material and produces 2-naphthol through 98% sulfuric acid sulfonation, salting out, alkali fusion, acidification, distillation and other processes. It overcomes the deficiencies of sulfonation, hydrolysis and blowing of naphthalene, neutralization, cold analysis, drying, alkali fusion, acidification and distillation in the traditional process, optimizes the process, shortens the process flow, reduces production costs, and does not generate wastewater; it has positive significance for environmental protection and is particularly suitable for the production and use of 2-naphthol. The two patents are very concise in their introduction to the acidification process, and the purpose of acidification is mainly to react the sodium 2-naphthol generated by alkali fusion with SO2 generated by neutralization reaction to generate 2-naphthol; and to neutralize the unreacted sodium hydroxide in the alkali fusion reaction. This step is very important and improper handling will cause pollution to the environment.

[0005] The process of producing beta-naphthol by retrieval of existing alkali fusion method specifically comprises the following steps:

[0006] (1) Alkali fusion: Sodium naphthalenesulfonate reacts with molten NaOH at 330-340°C to generate sodium 2-naphthol. The reaction equation is shown in Formula 1 below.

[0007]

[0008] (2) Dilution: adding the sodium 2-naphthol obtained in step (1) into water for dilution and cooling to prepare for acidification;

[0009] (3) Acidification: After dilution in the dilution pot, use compressed air to send the dilution liquid into the acidification pot. After the acidification pot is fed, close the feed valve and exhaust valve, notify the pump operator to start the vacuum pump, and open the vacuum valve on the pot to create negative pressure in the pot, then open the SO2 pipeline valve leading to the neutralization section for acidification. The SO2 flow time is 40-50 minutes, and then observe the material reaction (the color becomes lighter and brighter). When the neutralization operation is completed, close the SO2 valve of the neutralization pot and the SO2 valve of the acidification pot, stop stirring, take a sample and measure the pH value with pH test paper to 6-7, and send it to the laboratory for testing until the end point is qualified, ensuring that the sodium bisulfite is controlled at 2-4%. If the test fails, the next pot of neutralization must be filled with SO2 until it passes. After passing, close the vacuum valve, turn off the stirring, and notify the boiling station to prepare for receiving the material.

[0010] The above process not only has complicated operation steps and frequent operation, but also requires manual operation and has low safety. Therefore, there is an urgent need for a process with simple operation steps, high automation and high product stability to be applied to the production of 2-naphthol. Summary of the invention

[0011] Based on the deficiencies of the prior art, the present invention provides a 2-naphthol acidification section sulfur dioxide and alkali molten material reaction process using a dynamic tubular reactor, the process steps are simple, the degree of automation is high, and the safety is good.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] Acidification section: The alkali-melted material and SO2 dissolved with solvent are stored separately and fed into the dynamic tubular reactor at the same time according to the ratio for continuous flow reaction.

[0014] Wherein, the alkali melt material is sodium 2-naphthol, and the mass ratio of the sodium 2-naphthol to the SO2 feed is 5.1-5.4:1.

[0015] Preferably, the solvent in the acidification section is n-octadecane, n-tetradecane and n-nonane; n-tetradecane is further preferred.

[0016] Preferably, the mass ratio of the feed is 5.3:1, and further preferably, the mass ratio of the feed is 5.2:1.

[0017] Preferably, the reaction is carried out by controlling the feed flow rate of SO2 and the reaction temperature.

[0018] Preferably, the amount of SO2 in step (3) is 0.37-0.39t, more preferably 0.385t.

[0019] Preferably, the feed flow rate of SO2 in step (3) is 6.4-9.6 Kg / min; more preferably, it is 6.42 Kg / min.

[0020] Preferably, the reaction temperature in step (3) is 70-85°C, more preferably 75°C.

[0021] Preferably, the reaction time of the continuous flow reaction in the tubular reactor in step (3) is 3-6 min, more preferably 5 min.

[0022] Preferably, in step (3), the product is obtained by forced reaction in the reactor using a circulation pump.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The operation is continuous and automated, and the obtained products are highly stable.

[0025] 2. Both mixing efficiency and thermal conversion efficiency are improved, and the reaction time can be accurately controlled. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific embodiments. The embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention is described in detail with reference to the following embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the following embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0027] Basic Example: Preparation of 2-naphthol

[0028] The following steps are involved:

[0029] (1) Alkali melting: Sodium naphthalenesulfonate (2875 g) and molten NaOH (1000 g) were placed in an alkali melting pot and reacted at 330-340°C to generate sodium 2-naphthol.

[0030] (2) Dilution: After the reaction is completed, the sodium 2-naphthol produced in step (1) is discharged into a dilution pot filled with water through a bottom discharge valve to cool down in preparation for acidification.

[0031] (3) Acidification.

[0032] Example 1 A reaction process of 2-naphthol acidification using a dynamic tubular reactor

[0033] The next step of acidification is carried out on the basis of step (2) of the basic embodiment, and the specific operation is as follows:

[0034] Acidification: Store 420g of SO2 in a storage tank, add sodium 2-naphthol dissolved in n-tetradecane and SO2 in a ratio of 5.2:1 into a tubular reactor for continuous flow reaction for acidification. The flow rate of SO2 during feeding is 6.42kg / min, the reaction temperature is 75℃, and the reaction time is 5min.

[0035] Example 2

[0036] The only difference from Example 1 is that in the acidification stage, the solvent is n-octadecane, the reaction temperature is 70° C., and the reaction time is 6 min. The rest is the same as Example 1.

[0037] Example 3

[0038] The only difference from Example 1 is that in the acidification stage, the solvent is n-nonane, the reaction temperature is 85° C., and the reaction time is 3 min. The rest is the same as Example 1.

[0039] Example 4

[0040] The only difference from Example 1 is that in the acidification section, the feed amount of SO2 is 0.37t, and the ratio of sodium dinaphthol and SO2 is 3.9:1. The rest is consistent with Example 1.

[0041] Example 5

[0042] The only difference from Example 1 is that in the acidification section, the feed amount of SO2 is 0.39t, and the ratio of sodium dinaphthol and SO2 is 3.5:1. The rest is consistent with Example 1.

[0043] Example 6

[0044] The only difference from Example 1 is that in the acidification section, the feed flow rate of SO2 is 6.4 Kg / min, and the rest is consistent with Example 1.

[0045] Example 7

[0046] The only difference from Example 1 is that in the acidification section, the feed flow rate of SO2 is 9.6 Kg / min, and the rest is consistent with Example 1.

[0047] Comparative Example 1

[0048] The difference compared with Example 1 is that in the acidification stage, sodium 2-naphthol is fed into a tubular reactor, and then SO2 is introduced separately as a feed at a flow rate of 6.42 kg / min for acidification. The other steps are consistent with Example 1.

[0049] Comparative Example 2

[0050] The difference compared with Example 1 is that in the acidification stage, the reaction temperature is 65° C., and the other steps are consistent with Example 1.

[0051] Comparative Example 3

[0052] The difference compared with Example 1 is that in the acidification section, the feed flow rate of SO2 is 10Kg / min, and the rest is consistent with Example 1.

[0053] Effect experiment:

[0054] Experimental method: The mixing efficiency and thermal conversion efficiency of all embodiments and comparative examples were tested.

[0055] The testing method of mixing efficiency is gas chromatography, which adopts GB / T 9722-2023 standard.

[0056] Test method for thermal conversion efficiency: theoretical calculation method. The theoretical calculation method adopts DB33 / 642-2019 standard, which is the local standard of Zhejiang Province "Cogeneration efficiency, energy consumption limit and calculation method".

[0057] The test results of mixing efficiency and thermal conversion efficiency are shown in Table 1 below.

[0058] Table 1 Mixing efficiency and thermal conversion efficiency of each embodiment and comparative example

[0059] Mixing efficiency Heat conversion efficiency Example 1 98％ 98％ Example 2 98％ 95％ Example 3 98％ 93％ Example 4 97％ 94％ Example 5 96％ 94％ Example 6 94％ 93％ Example 7 94％ 92％ Comparative Example 1 92％ 92％ Comparative Example 2 98％ 89％ Comparative Example 3 97％ 91％

[0060] Test results analysis

[0061] It can be seen from Examples 1-3 that the effect is better when the temperature of SO2 is 75°C.

[0062] It can be seen from Examples 4 and 5 that the best effect is achieved when the feed ratio of sodium dinaphthoate to SO2 is 5.2:1.

[0063] It can be seen from Examples 6 and 7 that the best effect is achieved when the feed flow rate of sodium dinaphthol and SO2 is in the range of 6.4-9.6 Kg / min.

[0064] It can be seen from Comparative Example 1 that in the acidification section, under the condition of consistent feed ratio, by adjusting the order of feed, both the mixing efficiency and the heat conversion efficiency are reduced, which illustrates the necessity of feeding sodium dinaphthol and SO2 at the same time.

[0065] It can be seen from Comparative Example 2 that the reaction temperature needs to be within the temperature range set by the present invention to achieve the best effect.

[0066] It can be seen from Comparative Example 3 that the feed flow rate of SO2 needs to be within the temperature range set by the present invention to achieve the best effect.

[0067] In summary, when the process described in the present invention is used in the acidification process for producing 2-naphthol, not only is the operation continuous and automated, the obtained product has high stability and the mixing efficiency and thermal conversion efficiency are improved, but the reaction time can also be accurately controlled by the residence time of the feed amount in the equipment.

Claims

1. A reaction process using a dynamic tubular reactor in a 2-naphthol acidification stage, characterized in that: The process is as follows: the alkali-melted material and SO2 are stored separately, and are simultaneously fed into a dynamic tubular reactor according to a ratio for continuous flow reaction; wherein the alkali-melted material is sodium 2-naphthol, and the mass ratio of sodium 2-naphthol to SO2 feed is 5.1-5.4:

1.

2. The reaction process according to claim 1, characterized in that: The mass ratio of the sodium 2-naphthol to the SO2 feed is 5.2:

1.

3. The reaction process according to claim 1, characterized in that: The reaction process performs continuous reaction by controlling the feed flow rate of SO2 and the reaction temperature.

4. The reaction process according to claim 1, characterized in that: The feed amount of SO2 is 0.37-0.39t.

5. The reaction process according to claim 3, characterized in that: The feed flow rate of SO2 is 6.4-9.6 Kg / min.

6. The reaction process according to claim 3, characterized in that: The reaction temperature is 70-85°C.

7. The reaction process according to claim 7, characterized in that: The reaction temperature is 74-77°C.

8. The reaction process according to claim 1, characterized in that: The reaction time is 3-6 minutes.

9. The reaction process according to claim 7, characterized in that: The reaction time is 5 min.

10. The reaction process according to claim 1, characterized in that: The reaction needs to be carried out in a solvent, and the solvent is one or more of n-octadecane, n-tetradecane and n-nonane.

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